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College of Agricultural & Environmental Sciences

Department of Biological & Agricultural Engineering

An Assessment of the Recovery and Potential of Residuals and By-products from the Food Processing and

Institutional Food Sectors in Georgia

Prepared by: Ben Magbunua

Assisted by: Jason Govern0 Brian Kiepper Tom Adams

September 2000

Prepared for:

The Pollution Prevention Assistance Division Department of Natural Resources

Atlanta. Georgia

An Assessment of the Recovery and Potential of Residuals and By-Products from the Food Processing and

Institutional Food Sectors in Georgia

Executive Summary

The ultimate objective of this study was to identify and develop future opportunities and initiatives for the reduction and recovery of wastes generated by the food processing and foodservice sectors in the state. The food processing sector, as defined in the Standard Industrial Classification (SIC) system, represents a major portion of Georgia’s industrial base, and in 1995 employed 58,700 workers, with total payrolls of $1.42 billion, and consumed $9.41 billion of raw materials to produce $16.21 billion of manufactured goods, with $6.80 billion of value added (U.S. Bureau of the Census, 1998). With respect to institutional food waste generators, restaurants employed 253,800 statewide, 139,700 of them in the Atlanta Metropolitan Service Area (Georgia Department of Labor, 2000). Other establishments considered potential generators of institutional food waste include retail food stores, educational institutions, healthcare establishments, correctional institutions, and hotels and lodgings. The potential for waste generation in the food processing and institutional food sectors, given their considerable size and broad scope, was thought to be substantial, hence the development of alternatives and opportunities for the reduction and recovery of these wastes was expected to have major impacts, not only in preserving solid waste disposal (i.e., landfill) capacity, but potentially in the economical operation of these industries as well.

Information on the quantities and characteristics of wastes generated by the food processing industries in the state of Georgia is severely limited, but these were initially estimated using throughput-based and manpower-based waste generation factors. Subsequently, a limited industry survey was conducted to better quantify waste generation rates and to identify waste utilization and recovery patterns. Institutional food waste estimates, on the other hand, were based solely on waste generation factors selected from the literature.

These studies revealed that the quantities of food processing and institutional food Estimated generation rates and typical wastes generated in Georgia are considerable.

dlsposal and utilization methods for these residuals are presented in Table ES.1.

The Meat Products Industry which accounts for the largest employee base within the food processing sector, also generates the largest single by-product stream, 821,200 tons/year of inedible animal parts and meat. Most if not all of these materials, however, is converted by the rendering industry into animal feed. Large portions of this waste stream are generated in the Atlanta Regional Commission (1 27,600 tons/year), Georgia Mountains (1 92,900 tons/year) and Northeast Georgia (1 34,900 tons/year) Regional Development Council (RDC) coverage areas. Brewers’ and distillers’ grain and yeast (297,500 tons/year) and oilseed meals (8 10,000 tons/year) likewise represent substantial by-product streams.

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Table ES.l Estimated generation rates for food processing and institutional food wastes in the state of Georgia.

Waste Stream and Estimated Quantity, tons/year Utilization/Disposal Method Major Constituents

FOOD PROCESSING WASTE

Animal Matter

Offal, meat, bones, blood

Fish/seafood waste

DAF sludge

Eggshells

Grain

Waste flour or other ingredients, dough, or product, including dry cereal or snack chips

Brewer's/distiller's grainlyeast

Unusable feed

Fruit and Vegetable

Trimmings, fruit pomace

Waste sauces, salad dressing

Nut and Oilseed

Nut/seed hulls

2,870,900

1,073,900

821,200

6,800

249,600

30,700

393,300

95,300

297,500

200

235,200

231,100

4,100

1,168,800

358,800

Animal feed

Animal feed

Animal feed

Land application, animal feed

Animal feed

Animal feed

Landfill

Landfill, land application, animal feed in h t e d quantities

Composting/land application, animal feed possible

Animal feed/bedding, composting, land application, filler material, fuel

Oilseed meals 810,000 Animal feed

INSTITUTIONAL FOOD WASTE 474,200 Landfill, limited composting

Commercial Establishments 422,000

Educational Institutions 2,500

Military Installations 8,500

Health Care Establishments 6,400

Correctional Facilities 34.800

TOTAL 3,345,100

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Like inedible meat, these by-products are typically used as animal feed. Bakery wastes are also widely used for animal feed, and undergo a rendering or cooking process prior to feed formulation. On the other hand, fruit and vegetable trimmings (231,100 tons/year) and nut and oilseed hulls (358,800 tonslyear) appear to be underutilized and may represent a resource recovery opportunity.

Estimated wastewater generation rates and typical characteristics for the food processing industry in Georgia are presented in Table ES.2. The total quantity of wastewater was estimated at 18.8 billion gallons annually, with a biochemical oxygen demand (BOD) load exceeding 200,000 tons/year. The organic load of the wastewater not only represents

Table ES.2 Typical Characteristics, Estimated Volume, and Estimated Organic Loading of Wastewater Generated by the Food Processing Industry in Georgia.

Industry Group

Meat and Poultry Products

Dairy Products

Canned, Frozen and Preserved Fruits and Vegetables

Products

Bakery Products

Grain and Grain Mill

Sugar and Confectionery Products

Fats and Oils

Beverages

Miscellaneous Food Preparations and Kindred Products

Estimated Wastewater Volume (million gallons/ year)

10,730

500

2,080

130

530

140

350

3,660

700

Typical Characteristics

1,800 mg/L BOD 1,600 mg/L TSS 1,600 mg/L FOG 60 mg/L TI(N

2,300 g/L BOD 1,500 mg/L TSS 700 mg./L FOG

500 mg/L BOD 1,100 mg/L TSS

700 mg/L BOD 1,000 mg/L TSS

2,000 mg/L BOD 4,000 mg/L TSS

500 mg/L BOD

4,100 g/L BOD 500 mg./L FOG

8,500 mg/L BOD

6,000 mg/L BOD 3,000 mg/L TSS

Estimated Organic Loading (tons/year BOD)

80,600

14,900

4,300

300

4,400

300

7,000

91,000

5,600

TOTAL 18,810 208,600

Abbreviations: BOD, biochemical oxygen demand; TSS, total suspended solids; FOG, fats,

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lost product, but it is also converted into municipal biosolids. This becomes a problematic residual in publicly owned treatment works that receive the wastewater. Consequently, the wastewater represents a sipficant waste reduction opportunity.

Opportunities for the reduction and recovery of food processing residuals and institutional food waste are plentiful. The task is not to simply identify potential opportunities, but to focus on those that are technologically mature, or at least approaching that stage, and that can potentially effect substantial reductions in waste disposal volume and costs and accrue in economic benefits for the citizens of the state. Rather than focusing on specific potential products, technologies and sectors critical to the development food waste recovery processes are identified, and potential strategies to support the development and commercialization of these processes are discussed.

As indicated by Table ES.l, food processing residuals generated by the meat, poultry, seafood, bakery, and grain processing industries are substantially absorbed by the existing industrial infrastructure and converted into animal feed products, but collectively represent the largest waste volume in the food processing industry. Residuals generated by fruit and vegetable processing and by nut and oilseed processing, on the other hand, are substantially unused or underutilized. Waste from commercial and other foodservice operations, with the exception of a major composting enterprise operated by the Georgia Department of Corrections, is for the most part disposed of through municipal waste disposal systems. Potential strategies and initiatives for the reduction and recovery of these different residual materials will be considered. A number of initiatives are grouped together as a broad or overarching strategy, intended to impact a specific area or direction that affects food waste reduction and recovery. The remaining initiatives are grouped by type of activity, i.e., education/ technology transfer, research, and policy.

Water conservation should be aggressively pursued given that a substantial quantity of wastewater, estimated at 18.8 billion gallons/year, is generated. This wastewater is estimated to carry 208,600 tons of organic material (as BOD), hence the treatment of this wastewater in publicly owned treatment works (POTWs) results in the generation of another problematic residual, municipal biosolids. Furthermore, municipal water supplies generally undergo a series of treatment operations, including coagulation, sedimentation, filtration, and disinfection, operations which consume chemicals, energy, and manpower, and generate solid residuals. Therefore, if significant reductions in industrial water usage can successfully be realized, the potential impact is significant. In order to promote and achieve water conservation in the food processing industry, the following strategies should be pursued:

Educational and outreach programs intended to train production and maintenance personnel and superintendents should be widely offered to industrial clients. These programs should be designed to provide as much practical, hands-on information as possible. These programs should be scheduled and located such that they would be accessible to plant personnel, and given typically tight productions schedules this will often mean that the programs will need to be held at the plant site, and that the training materials and equipment be sufficiently portable to permit this. These programs should also be delivered in a medium that permits free communication between the trainer and the target audience, and given the demographics of

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industry production workers this may require fluency in a language other than English.

0 Training on techniques to limit the quantity of organic material carried by the wastewater, such as dry cleaning, spill control, microscreening, and membrane filtration, should be offered and conducted as well.

Research aimed at developing sanitation and food safety practices consistent with HACCP objectives but entailing minimal water usage should be undertaken. This may include the development of alternative disinfection methods and the use of advanced techniques for detecting microbial contamination.

Research and demonstration projects on industrial water reuse should be undertaken. The demonstration phase is critical for this activity to show that food safety goals can be achieved even with water reuse provided that the appropriate technology is used and is implemented in the proper manner.

Research on the development of processing alternatives that minimize water usage should be undertaken. Examples include the use of steam rather than aqueous solutions for peeling operations and of air jets rather than water baths for initial cleaning in fruit and vegetable processing.

0 A critical review of effluent regulations instituted by different local jurisdictions should be undertaken. Because water use reduction may result in increased effluent concentration, plants that undertake water conservation programs could potentially be penalized for their success if effluent regulations are based on concentration limits. Mass-based limits, on the other hand, would permit an operation to reduce the quantity of its wastewater while continuing to discharge the same amount of organic material. Hence, mass-based effluent limits appear more conducive to industrial water conservation, however concentration-based limits may be necessary to ensure reliable treatment plant performance. The development of effluent regulations that would address both of these objectives would require a comprehensive review of the wastewater load, the treatment capacity, and the effluent requirements of the POTW. Such an exercise should be encouraged by the state regulatory agencies, with technical assistance to be provided by the state body or by the GEP technical partners, if needed. Such a review might also be conducted in conjunction with a review of the billing structure for industrial water users, which can also be tailored to promote water conservation.

While the continuing depletion of non-renewable resources provides substantial impetus towards a biobased products manufacturing infrastructure, much of the infrastructure and technology required to achieve such a shift are not currently in place. Even in the case of ethanol production, which is a relatively mature industrial fermentation process, technologies for the production of ethanol from lignocellulosic waste via hydrolysis and fermentation have aroused little commercial interest. A novel technology for

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simultaneous saccharification and fermentation of 5- and 6-carbon sugars is in the early stages of a demonstration process, and could take several years to validate (National Research Council Committee on Biobased Industrial Products, 2000). Particularly with respect to by-product utilization, a collection infrastructure exists only for those residuals with established products and markets, and even then small-scale generators are rarely served by it. Consequently, the large-scale utilization of Georgia's food processing residuals and institutional food waste in industrial-scale by-product recovery operations would require both technological and infrastructure development.

A possible approach is described by the biorefinery concept (National Research Council Committee on Biobased Industrial Products, 2000). Like a petroleum refinery, a biorefinery would be a processing facility which utilizes one or a limited number of feedstocks to manufacture a range of products. A potential biorefinery facility could be based on a wet corn milling plant, which could potentially produce corn starch, corn syrup, dextrose, dextrins, organic acids and biochemicals, ethanol, and feed ingredients. Some lessons from the operation of petroleum refineries, which would also be applicable to biorefineries, include:

Refineries produce more and more products from the same feedstock over time, thereby diversifying outputs.

Refineries are flexible and can shift outputs in response to change.

Processes in refineries improve incrementally over time.

Process improvement invariably makes the cost of raw material the dominant factor in overall system economics.

With respect to waste reduction and recovery, a biorefinery operation would have a substantial incentive to develop alternative products and processes for by-product and waste utilization. Furthermore, a biorefinery would be well organized to pursue such possibilities, especially with respect to ensuring that by-product and residuals are of a quality suitable for recovery as other value-added products. Consequently, the development of biorefineries to undertake food processing activities would lead to the reduction of food processing residuals. For example, biorefineries could be established around two of the state's major crops, soybeans and peanuts. The possibility of soybean-based biorefineries producing oil, protein isolates, food products and supplements, and feed has been suggested (National Research Council Committee on Biobased Industrial Products, 2000), and the possibility of ultimately converting the hulls into chemical products would make such a venture more attractive. A similar biorefinery could conceivably be structured around peanut processing as well, although the current product range for soybeans appears broader, more diverse, and more versatile compared to peanuts. At the same time, nuts and oilseed hulls, estimated at 358,800 tons/year, are a major food processing residual, and are utilized primarily for composting, for animal bedding, and to provide roughage in feeds, although a limited quantity of pecan hulls is ground for use as filler in plastic production. Whether it would be more beneficial to a biorefinery to process the shelled nuts or seed, or shell the raw material on-site and use the shells to manufacture additional products would depend to a great extent on the products that could be derived from the shells. Regardless of whether or not shelling

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is integrated into the refinery operation, however, the lignocellulose represents a potential resource, and initial research efforts would focus on the conversion of the lignocellulosic material into fermentation feedstocks and chemical commodities, with mme specialized chemical products targeted for longer-term development. The establishment of biorefineries based on soybean and peanut processing would also be consistent with the rural development goals enunciated by the state.

The biorefinery concept appears to hold up well for products such as corn,soybeans, and peanuts, which are rather versatile and from which a wide range of products can be manufactured through established technologies. Whether such an approach would be viable for another the state's major agricultural products, poultry, is another matter. In theory a wide array of products could be manufactured in an industrial complex having a poultry slaughter and dressing operation as its front end, including food additives, protein isolates, oil, biofuels, feed ingredients, and insulation. Additional development of many of these technologies is required, however, before such a facility can be realized. Furthermore, the establishment of biorefineries around poultry processing plants would challenge current industry practice of shipping residuals off-site for rendering into animal feed. The refinery could nevertheless be a useful model, due to the economic benefits of having multiple, tightly integrated, symbiotic operations at a single site.

In order to promote the establishment of biorefineries as a vehicle for rural development and more efficient resource utilization, the following initiatives should be undertaken:

0 A committee should be appointed by the state to evaluate the feasibility of and develop an implementing plan for the establishment of biorefineries based on major agricultural products of the state. This could initially be limited to those products for which a wide range of processing options are currently available, i.e. peanut and soybean, and to those produced in an extremely large volume, i.e. poultry. The committee would identify potential research and technology requirements, financial requirements, candidate sites, and potential industry partners, among other things. Note that a committee constituted to evaluate the biorefinery concept would not be restricted to food crops, and would probably evaluate non-food crops (e.g., cotton) as well.

Research that would expand the range of potential products from the candidate biorefinery crops should be undertaken. Examples of such research include the hydrolysis of nut hulls into fermentable carbohydrates, and enhanced oil recovery from poultry processing and subsequent biofuel production.

Regardless of whether the biorefinery concept is pursued, a strategy that would initially focus on established products, technologies, and infrastructure, while investing in the development and expansion of these for an eventual shift into more novel, higher-valued products, appears to be the most reasonable approach for enhancing waste recovery in the food processing and institutional food sectors. This does not necessarily mean that markets currently served by the residuals will be abandoned, but that alternative higher-value markets

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Table ES.3 Current and potential products from different food processing residuals.

Industry/Activity Residual(s) Future Products Current Products/ Disposal Methods Intermediate Long- term

Meat, poultry and Offal, blood, Animal feed Animal feed, including Protein isolates feathers, DAF lactic acid Animal fats, seafood

processing sludge fermentation biofuels Insulation material

Bakery operations Waste doughs, Animal feed Feed ingredients, via Specialty chemicals and grain breads, bakery SCP production or processing ingredients, lactic acid

waste grain, fermentation spent brewer's/ Fermentation distillers' grain/ feedstocks yeast Commodity chemicals

Fruit and Trimmings, culls, Landfill, land Feed ingrechents, via Biofuel(s) vegetable fruit pomace application, SCP production or Commodity and processing animal feed lactic acid specialty

fermentation chemicals Methane/biogas

Nut and oilseed Hulls, meals Compost, animal Fermentation Specialty chemicals processing feed, plastic feedstocks

filler Biofuel(s) Commochty chemicals

Dairy products Whey Food and feed in Commodity and Specialty chemicals limited specialty chemicals quantities

Beverage Waste beverage Municipal sewer Biofuels Specialty chemicals products

will be sought and developed to enhance by-product recovery and to reduce potential constraints imposed by waste and by-product management requirements on future industry growth.

Current products from different food-based residuals are listed in Table ES.3, along with intermediate- and long-term product goals for these residuals. Among the food processing industries, the first four industry groups listed (meat, poultry and seafood processing; bakery operations and grain processing; fruit and vegetable processing; and nut and oilseed processing) produce the largest quantities of residuals and would probably deserve the greatest amount of attention and resources with respect to waste reduction efforts.

For meat, seafood, and poultry processing, the current residual collection and processing infrastructure appears effective in capturing substantially all of the waste material and converting it into animal feed. In addition, research on the conversion of these residuals into alternative, higher-value products has not been pursued as aggressively as research on

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the conversion of lignocellulosic wastes, except possibly in the area of enzymatic conversion, Le., lactic acid fermentation into animal feed ingredients. Consequently, the lead time required for the development of new products from these materials is probably longer compared to other residuals, and the maintenance of the current residual recovery products and infrastructure would constitute the main intermediate-term objective.

Like meat, poultry, and seafood processing residuals, residuals from the bakery and grain processing industries are typically recovered as animal feed, with waste doughs even undergoing a rendering process to produce a dry feed ingredient. In contrast to those proteinaceous wastes, however, bakery and grain processing residuals contain a large amount of or are readily converted enzymatically into reducing sugars that can serve as feedstock for industrial fermentation processes. Since this material is primarily starch rather than cellulose or l i p n , the hydrolysis process is much better established. Also, this material is solid or semisolid and could serve as a good substrate for solid-state fermentation processes. Potential intermediate-term technologies are the production of chemicals and SCP- or lactic acid-enhanced feeds through solid substrate fermentation, and of fermentation feedstocks and/or chemicals through hydrolysis and/or fermentation.

Fruit and vegetable processing residuals would be mainly cellulosic in nature, and although hydrolysis of this type of material is possible it has not been commercially applied to a great extent. Although potentially usable as animal feed, their high moisture content and low nutrient content makes the delivered cost of these residuals prohibitive. It may be possible to enhance the feed value of these materials through SCP production or lactic acid fermentation, but this may be difficult, particularly with vegetable trimmings, due to the limited concentration of fermentable material, unless supplemental substrate is provided, preferably in the form of a waste material with a complementary nutrient profile. An alternate course is to use anaerobic digestion to produce biogas, while the possibility of more desirable products through cellulose hydrolysis and fermentation is explored.

Whey produced by the dairy industry is used in both food and feed production, but in limited quantities only. As noted earlier, the supply of whey far exceeds the demand for products derived from it, and there are no new technological developments that promise to change this situation (Council for Agricultural Science and Technology, 1995). Nevertheless, the range of potential products from whey is large; and provided the necessary markets can be developed, the recovery of this residual should become a viable activity.

Residuals from the production of grain-based fermented beverages are generally utilized for food (brewer's yeast) and feed production, while the grape pomace generated by Georgia's small winemaking industry is returned to the vineyards to fertilize the next crop. Chemicals are potentially recoverable from the grape pomace via biological or chemical means, but the quantity of this residual is small. Waste beverage from soft drinks packaging operations, given its sugar content, is potentially usable as fermentation medium, perhaps requiring no more than pH adjustment prior to inoculation, and is a potential raw material for biofuels and chemicals.

Institutional food wastes are currently disposed of mostly through municipal solid waste management systems, Le., by landfilling. One exception is the Georgia Department of Corrections food waste composting program, which diverts more than 8,500 tons/year of

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waste from landfills. However, this is only a small fraction of the total amount of institutional food waste generated in Georgia, estimated at 474,000 tons per year. Of that amount, an estimated 422,000 tons (89O/0) is generated by commercial establishments, of which restaurants produce the bulk. Consequently, institutional food wastes represent a large pool of material, and their reduction or recovery could potentially have a substantial impact on the quantity of food-based residuals disposed of in landfills. Other than composting, two possible means to recover the value in institutional food wastes are animal feed production and anaerobic digestion. Feed products obtained through the processing of institutional food wastes would be specifically prohibited from inclusion in swine rations, to avoid public and animal health problems, and standards on pathogen destruction, nutrient content and stability would have to be established and maintained. Nevertheless, and despite existing Georgia law, animal feed seems to be a product towards which institutional food wastes could readily be diverted. Anaerobic digestion is another alternative, although biogas is not considered a very desirable product. Over the longer term, the evaluation and development of the food waste as a feedstock in solid or liquid fermentation could be examined. The nutritional profile of the material may permit microbial cultivation with minimal micronutrient augmentation, enhancing the economics of its utilization. On the other hand, sterilization requirements for the waste may be more stringent compared to alternative raw materials. Another issue may be the potential variability in the composition of the waste. Particularly if the fermentation process places stringent requirements on medium composition, it may be necessary to limit the types of waste accepted, to frequently test the medium, to have alternative substrates for blending, or even to avoid use of the waste altogether. Solid substrate fermentations, however, are more flexible in this respect 1

than traditional liquid phase fermentation processes, and could consequently be preferrable.

Application of a system for institutional food wastes recovery could be substantially constrained by the logistics of waste collection, considering that the bulk of the waste is generated by a large number of relatively small establishments that currently do not consider the disposal of their waste a problematic issue. However, when the feeding of these residuals to swine was permitted, these issues were apparently dealt with successfully by the swine farmers who collected and used the waste, so it is clear that these issues can be overcome at some scale. It may be possible to avoid these logistics issues during the technology development and demonstration phase by a undertaking a cooperative project with a large institutional food waste generator, possibly one with an established collection and/or recovery system. Wider-scale implementation of an institutional food waste recovery process, however, would require that these issues eventually be addressed and surmounted. With these concerns in view, the following initiatives are recommended to promote increased recovery of institutional food wastes:

Review current regulations on the use of institutional food wastes for animal feeding, with the end result being the development of a policy structure that maximizes the beneficial reuse of institutional food waste for animal feeding purposes while safeguarding animal and human health.

Assess the logistical issues related to the collection of institutional food wastes, particularly in situations where the waste is produced mostly by multiple small generators (e.g. restaurants) and develop management

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strategies and state-supported incentives that would permit potential processors to undertake this activity more economically.

Research on the processing of institutional food waste into animal feed ingredients should be undertaken. The research would establish the processing methods and techniques required to eliminate or minimize the public and animal health risks associated with feeding institutional food waste to livestock.

0 Research on the incorporation of processed institutional food waste into swine, dairy, beef cattle, broiler, and layer operations should be conducted. The research would also establish the levels at which the processed institutional food waste could be incorporated into feed rations while meeting the nutritional requirements of the animals and obtaining.

0 Research on the use of institutional food for fermentation process feedstock should be conducted. The research would assess the preprocessing operations, e.g. grinding, homogenization, sterilization, nutrient supplementation, etc., required before the waste can be used for fermentation. The research will also investigate specific products for which the institutional food waste may be a particularly suitable raw material.

The need for more information on waste reduction and recovery programs and opportunities was identified earlier, hence education and technology transfer is an important component towards achieving pollution prevention goals. Specific initiatives in this area include:

Technical assistance activities of the GEP partners should be continued and strengthened. Although it appears that relatively few companies are aware of them, these services are generally received quite positively. However, efforts should be made to more broadly promote GEP services to industry. The services provided by the GEP partners include:

o Technical assistance through site assessments for waste reduction and recovery. Personnel from GEP partner organizations assist plant personnel in identifying and exploring waste reduction opportunities, and assist in the implementation of any waste reduction measures adopted.

o Technical assistance in environmental and regulatory compliance. As noted earlier, the need to comply with environmental regulations is the common driving force behind waste reduction and treatment efforts. Personnel from GEP partner organizations have many times been called in initially to assist on environmental compliance issues, and any help provided in this area has in our experience always been greatly valued and appreciated and very well-received by industry. Such contacts provide the opportunity to have the client examine waste reduction measures as a means of achieving environmental

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compliance as well as cost reduction, and as an alternative to more conventional waste treatment or disposal methods. Technical assistance in the area of environmental compliance has proven a particularly effective means of introducing clients to potential waste reduction opportunities in their processing operations. Linkages between the GEP partnership, the Georgia Department of Natural Resources Environmental Protection Division, and local regulatory bodies should be cultivated to identify potential client companies that could benefit from waste reduction and recovery. This should not conflict with the non-regulatory role of the Pollution Prevention Assistance Division, since its services are restricted to technical assistance and technology transfer and it has no role in assessing environmental compliance. This assistance may involve helping clients to respond to a notice of violation from local or state environmental regulators, to identify waste reduction and recovery alternatives that may help achieve environmental compliance, and to decipher and comply with regulatory requirements and permit guidelines pertinent to their operation.

0 Training on the use of full-cost accounting as a decision support tool in the institution of waste reduction measures should be provided to industry and corporate personnel. Very often, the true cost of a waste material is not realized. For process losses, e.g. spills, typically the only cost considered is the price of the material itself. For processing residuals, on the other hand, the costs of treatment and/or disposal are the main cost components considered. To reflect the true cost of the waste, the inputs involved in acquiring, handling, and processing the material prior to its becoming a waste, and the cost collecting, handling, treatment, and disposal of the waste should all be considered. Full-cost accounting techniques would consider all cost factors, and enable managers and manufacturing personnel to justify the cost equipment and operational modifications adopted to achieve waste reduction.

Publish and circulate waste reduction guides targeted to institutional food waste generators. Such documents should contain simple, easily implemented measures for waste reduction explained in readily understandable language.

Research is required to validate the benefits and effectiveness of waste reduction and to develop technologies for resource recovery. Specific research needs include:

Field-based grading and cleaning of the produce could substantially reduce the quantity of residual material generated at the processing plant, and facilitate the return of these materials to the soil. This practice should be strongly encouraged since options for the recovery of fruit and vegetable waste appear limited. Demonstration activities that would validate the benefits of this practice should be conducted, along with research to developed improved mechanical harvesting equipment.

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Research to improve and optimize the enzymatic hydrolysis of cellulosic and lignocellulosic substrates should be undertaken. Hydrolysis is a necessary step preliminary to fermentation for the production of ethanol, however improvements in conversion and yield of cellulosic and lignocellulosic substrates would probably need to be realized before commercial-scale application becomes attractive (National Research Council Committee on Biobased Industrial Products, 2000). Adoption and optimization of the hydrolysis process for different residual materials would therefore be a top research priority, and will be key to broadening the utilization of lignocellulosic material for industrial fermentation.

0 Research on the development of alternative products from meat, poultry, and seafood processing residuals should be undertaken. These products could include lactic acid-enhanced feeds, protein isolates, animal fats, biofuels, and insulation material.

Research on the bioconversion of wastes from bakery and grain processing should be performed. Enzymatic hydrolysis and liquid fermentation could be used to produce chemicals and fermentation feedstocks, while solid state fermentation could produce chemicals and SCP- or lactic acid-enhanced feeds.

Research on the bioconversion of fruit and vegetable trimmings should be undertaken. The feed value of these materials could be enhanced through solid state fermentation, or energy could be derived from them through anaerobic digestion.

Research on the bioconversion of nut and oilseed hulls should be undertaken. Hydrolysis of these lignocellulosic materials would produce fermentation feedstocks, which could subsequently be converted into chemical commodities.

Research to quantify the benefits of composting and land application should be undertaken. The results of this research should be made available on a timely basis to the food processing industry, to institutional food waste generators, and to potential compost producers.

Research on odor control and minimization in the rendering industry should be undertaken to secure this market for food processing by-products.

Research to examine alternatives and/or enhancements to the dissolved air flotation process commonly used for separation of protein and fat from poultry processing wastewater should be undertaken. Alternatives techniques and end products for processing the DAF sludge should also be investigated .

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0 Research and demonstration on techniques that can be used for volume and mass reduction of food wastes prior to further processing and recovery should be conducted. Transport costs are expected to become a major factor affecting the profitability of resource recovery operations utilizing food wastes and techniques that would reduce waste volume and mass while retaining the desirable properties of the waste material could substantially reduce these expenses.

Policies that would promote waste reduction and utilization should be formulated and implemented. Potential policy initiatives include:

0 Policies regulating the composting of food processing and institutional food wastes should be reviewed. For example, Permit-by-Rule provisions in the state solid waste regulations (Georgia Department of Natural Resources, 1997) apply only to operations where 75% or more of the composted material is generated on-site, although it is not clear why composters that obtain more than 25% of their material off-site pose a higher risk. While the need to safeguard public health and environmental quality is recognized, the solid waste regulations do not in general encourage composting, and should be modified to promote resource recovery.

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TABLE OF CONTENTS

Page

PART I11 . WASTE REDUCTION AND RECOVERY OPPORTUNITIES

111.1. Introduction ...................................................................................................................... 111-1

Evaluating Opportunities for Waste Reduction and By-Product Utilization .......... 111-2

Recoverable Values from Food By-Products and Waste ........................... 111-2

111.2.

111.2.1.

111.2.2. Waste Reduction and Recovery Hierarchy ..................................................... 1-2

111.3.

111.4.

Source Reduction Opportunities .. ................................................................................... 1-5

Waste Recovery and Utilization Opportunities ......................................................... 111-10

111.4.1. Biotechnological Opportunities ..................................................................... 1-10

111.4.2. Recovery for Human Uses ........................................................................... 111-18

111.4.3.

111.4.4.

Recovery for Energy ...................................................................................... 111-20

Recovery for Animal Uses ............................................................................ 111-22

111.4.5. Recovery for Soil Conditioners or Fertilizer .............................................. 111-26

111.5. Barriers to Waste Reduction and Recovery ............................................................... .I1 1.29

Techno-Economic and Technology Delivery Issues ................................ 111-29 111.5.1.

111.5.2. Logistical Issues .............................................................................................. 111-35

111.5.3. Environmental and Public Health Issues ................................................... 111-36

111.5.4. Regulatory Issues ............................................................................................ 111-37

111.6. Strategies to Enhance Reduction and Recovery of Food Processing Residuals and Institutional Food Waste ....................................................................................... 111-39

111.6.1 . Water Conservation ....................................................................................... 111-39

111.6.2. Establishment of Biorefineries for Processing Traditional Agricultural Products ..................................................................................... 111-41

111.6.3. Phased Development of Food Waste Utilization and Recovery Technologies and Industries ......................................................................... 111-43

1

111.6.4.

111.6.5.

111.6.6. Research Initiatives .......................................................................................... 1-48

Recovery of Institutional Food Wastes ........................................................ 1-45

Education and Technology Transfer Initiatives ........................................ 111- 46

111.6.7. Policy Initiatives ............................................................................................ .III-49

11

Table

111.4.1

111.4.2

111.4.3

111.4.4

111.4.5

111.4.6

111.5.1

111.5.2

111.5.3

111.5.4

111.6.1

LIST OF TABLES

Page

Selected products manufactured through industrial fermentation processes. .................................................................................................................... 1-12

Carbon sources commonly used in industrial fermentation processes. .......... 111-13

Nitrogen sources commonly used in industrial fermentation processes. ........ 111-1 3

Comparison of enzymatic hydrolysis and acid hydrolysis of cellulosic material into glucose ................................................................................................ 111-14 . .

Possible downstream products derived from cellulose, hemicellulose, and l i p n via biotechnological and industrial fermentation processes. .................. 111-1 5

Potential products from the recovery and processing of whey. ....................... 111-21

Bulk prices of selected chemicals, as of week ending 26 May 2000 ................. 111-31

Bulk prices of products derived from food processing residuals, or competing with such products. ............................................................................. 111-32

Shipments of selected products, nationwide and in Georgia. ........................... 111-33

Size and projected annual growth of selected market segments of the specialty chemicals industry. .................................................................................. 111-34

Current and potential products from different food processing residuals. .... 111-44

... 111

111.1. INTRODUCTION

Whereas Parts I and I1 focus on the quantification and characterization of food waste generated in Georgia and on identifying the patterns by which they were utilized or disposed of, Part I11 focuses on opportunities for waste reduction and recovery. Hence, this part will:

Identify opportunities for waste reduction and pollution prevention in the food processing industry, particularly initiatives that could potentially result in a substantial reduction in the quantity of solid waste being landfilled.

0 Identify barriers and constraints to increasing the quantity of food processing waste that is recovered and beneficially reused.

0 Recommend measures, including research initiatives, that would facilitate the utilization of food processing waste and consequently increase the quantity that is beneficially reused and reduce the quantity being landfilled.

With these aims in view, the project team conducted extensive literature studies to identify technologies and strategies for waste reduction and utilization, particularly those whch would have potential application in the food processing industry under conditions prevalent in the state of Georgia. The literature research and industry surveys revealed that in Georga the greatest quantity of industrial food processing residuals originate from the meat and poultry industry. These residuals, however, are for the most part utilized or converted into animal feed. Sigmficant amounts of residual material are likewise produced by the bakery and grain (including grain-derived beverages) industries, and these are utilized for animal feed. "he greatest quantity of unused or under-utilized waste is in the form of fruit and vegetable trimmings and seed and nut hulls. Wastes from other food processing industries, including beverage and dairy production, were smaller in quantity and predominantly liquid in form. The wastewater generated by the food processing industry, estimated at 18.8 billion gallons annually, and the organic material associated with it, estimated at 208,600 tons/year, represent significant quantities of waste. Institutional sources, i.e. foodservice activities and retail food establishments, are another major source of waste. A limited quantity of this material is currently composted, although there appears to be a growing impetus to establish institutional food waste reduction and utilization programs.

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111.2. EVALUATING OPPORTUNITIES FOR WASTE REDUCTION AND BY-PRODUCT UTILIZATION

111.2.1. RECOVERABLE VALUES FROM FOOD BY-PRODUCTS AND WASTE

Food processing residuals and institutional food waste present an interesting management challenge. On the one hand, such residuals are typically non-hazardous and can be disposed of through conventional means. However, this is typically not the best management strategy for a number of reasons:

Food wastes contain a significant quantity of chemical energy and nutritional value, in the form of organic matter such as carbohydrates, proteins, and lipids, are generally free of metals, pesticides, and other toxic compounds and low in inorganic solids (Kroyer, 1991), and as such represent resources that can be recovered and utilized.

Many food processing activities generate a quantity of waste that is large in proportion to the quantity of product. For example, poultry slaughter operations generate about 0.31 lb of residuals (feathers, heads, viscera, blood) for each pound of dressed poultry produced (National Agricultural Statistics Service, 1998), and up to 10 gallons of wastewater per 4-5 lb bird (Merka, 1998). Consequently, even if the material is non-hazardous and can be disposed of in a conventional landfill, the cost of doing so would be significant.

Most food wastes undergo rapid degradation, which can be accompanied by the generation of unpleasant odors, the proliferation of vermin, vectors, and pathogens, and other events that would be undesirable in a facility handling large quantities of food.

111.2.2. WASTE REDUCTION AND RECOVERY HIERARCHY

In approaching the issue of food processing residual management, Brandt and Martin (1 996) recommend a hierarchical approach. This approach first considers options that provide the highest benefit to both the environment and the processor. In the order of descending benefit, food processing residual management options may be grouped as €allows:

Source reduction and water conservation. This management strategy reduces excessive waste generation. All processing plants practice this technique to some degree, but even more significant reductions can be achieved by a concerted, focused approach. Source reduction can be accomplished by reducing material loss, conserving and reusing water, and preventing spills.

Recoverv for human uses. This management strategy recovers food processing residuals for human ingestion, personal care, home use, or

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commercial/industrial use. Some examples of food processing residuals recovered for human uses include thermally modified whey proteins used as food additives and starch-based biodegradable packaging materials. Use of the waste as a fuel, directly or after further processing, is also considered recovery for human use; this would encompass heat recovery from waste incineration/cogeneration operations.

Recoverv for animal uses. This management strategy uses food processing residuals primarily for animal consumption, as well as for other products such as animal. Examples include pet food and livestock feed from meat, poultry and seafood processing residuals, and broiler litter from peanut hulls.

Recoverv for soil conditioners or fertilizers (land application). This can be accomplished either through composting or through land application. Although ranked relatively low on this hierarchy, composting is typically perceived as the conversion of a waste material into a product of commercial value. Composting can be performed on a wide range of food processing residuals and on institutional food waste. Conversely, land application is often viewed as a disposal option. However, properly managed land application programs strive to replenish soil organic matter and nutrients that have been depleted through cropping, with the objective of replacing conventional soil supplements and chemical fertilizers with food processing residuals. Land application programs should be undertaken with nutrient plans that will prevent accumulation of substances that would inhibit plant growth or otherwise limit the future use of a site. Crop harvest and attention to productivity set land application apart from disposal practices. Land application has been used as a management strategy for wastewater and waste sludges generated by food processing activities.

Disposal via landfill. impoundment. or incineration. This disposal strategy has no benefit to society other than to capture, contain, and control the release of potentially harmful contaminants. As in most businesses, the manager's objective is to find the least expensive, environmentally responsible management method for waste generated. All disposal options involve an extensive evaluation of waste characteristics since the type of facility required for disposal depends on these characteristics. As mentioned above, a food processing residual with a high heating value is considered to have been recovered for human use if it is incinerated and its heat of combustion is captured and put to beneficial use.

Disposal at a hazardous waste management facility. Any material that has been contaminated with a hazardous substance or exhibits hazardous characteristics (ignitability, corrosivity, reactivity, or toxicity) must be handled as a hazardous waste. A food processing residual becomes a hazardous waste only under certain circumstances. An example is a spill of a toxic cleaning agent into a food processing. residual stream: the entire contaminated stream " "

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would then have to be managed as a hazardous waste, unless the hazardous contaminant or quality was removed from the system.

This hierarchy has been considered in evaluating and presenting options for waste reduction and recovery of food processing residuals and institutional food waste.

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111.3. SOURCE REDUCTION OPPORTUNITIES

Vast quantities of water are used as a whole in the food processing industry, of which a small proportion is for consumptive use, and the resulting wastewaters are characterized as dilute streams containing proteins, sugars, starches, and fats (ICroyer, 1991). Hence, the largest single opportunity for source reduction in the food processing industry is water conservation, and the corresponding reduction in wastewater volume that would be realized. Given that food processing plants in Georgia annually discharge an estimated 18.8 billion gallons of wastewater, with an estimated organic loading of 208,600 tons, significant benefits would be realized by the industries and by the local governments that host them. The industries would benefit through reduced water bills and reduced cost of wastewater pretreatment operations, while local governments would benefit through the increased availability of water resources, reduced burden on the water and wastewater systems, and enhanced environmental quality. In addition, it should be recognized that since wastewaters discharged into a municipal undergo further treatment in a public-owned treatment works (POTW), the organic content of food processing wastewaters would to a large extent be converted into municipal biosolids, which represent a sigmficant disposal issue in Georgia.

A number of approaches to achieving water conservation are available. Water leaks of course should be repaired as soon as possible. The use of low flow devices in sanitation operations should be practiced, as equivalent cleaning efficiency can often be realized by using lower flows at higher pressures. Water reuse is another option that should be considered. In operations where the objective is simply the removal of particulate debris; e.g., in washing produce, water may be reusable after grit removal. Countercurrent washing trains can also be used in lieu of a single wash. Reducing fresh water use has an addttional advantage of reducing the nutrients being leached out of produce during the wash process. In poultry processing operations, make-up water for scalding need not be fresh water; relatively clean water from chilling operations can be diverted for this use. The largest constraint to water reuse in food processing operations is the concern over possible food safety issues arising from possible retention of pathogenic microorganisms in the recycled water. This problem can be prevented through disinfection, using chlorine, hypochlorite, ozone, ultraviolet radiation, or a combination of these. However, it must be ensured that the expense of the disinfection process does not negate the savings realized through water reuse.

Much of the water use in the food processing industry is non-consumptive (ICroyer, 1991), i.e., the water emerges from the process as a waste, usually laden with undesirable materials, after use in cleaning or other operations. Hence, measures designed to minimize the inclusion of organic matter and other contaminants with the wastewater should be strongly linked to water conservation efforts. Such measures include dry cleaning of equipment and the process floor, the strategic placement of containers to catch spills, and even the use of sophisticated equipment to physically recover solids from the wastewater stream. Unless the quantity of contaminants entering the wastewater stream is reduced, water conservation may actually make it more difficult for a company to achieve compliance with wastewater regulations. This is because decreasing water use without reducing the mass of organic material lost to the wastewater will result in a waste of higher concentration. In some jurisdictions effluent regulations are based on concentration; reducing water use may actually push a company out of or further from compliance. However, when regulations are

111-5

111.3. SOURCE REDUCTION OPPORTUNITIES

Vast quantities of water are used as a whole in the food processing indusuy, of which a small proportion is for consumptive use, and the resulting wastewaters are characterized as dilute streams containing proteins, sugars, starches, and fats (IGoyer, 1991). Hence, the largest single opportunity for source reduction in the food processing industry is water conservation, and the corresponding reduction in wastewater volume that would be realized. Given that food processing plants in Georgia annually discharge an estimated 18.8 billion gallons of wastewater, with an estimated organic loading of 208,600 tons, sipficant benefits would be realized by the industries and by the local governments that host them. The industries would benefit through reduced water bills and reduced cost of wastewater pretreatment operations, while local governments would benefit through the increased availability of water resources, reduced burden on the water and wastewater systems, and enhanced environmental quality. In addition, it should be recognized that since wastewaters dscharged into a municipal undergo further treatment in a public-owned treatment works (POTW), the organic content of food processing wastewaters would to a large extent be converted into municipal biosolids, which represent a significant disposal issue in Georgia.

A number of approaches to achieving water conservation are available. Water leaks of course should be repaired as soon as possible. The use of low flow devices in sanitation operations should be practiced, as equivalent cleaning efficiency can often be realized by using lower flows at higher pressures. Water reuse is another option that should be considered. In operations where the objective is simply the removal of particulate debris; e.g., in washing produce, water may be reusable after grit removal. Countercurrent washing trains can also be used in lieu of a single wash. Reducing fresh water use has an additional advantage of reducing the nutrients being leached out of produce during the wash process. In poultry processing operations, make-up water for scalding need not be fresh water; relatively clean water from chilling operations can be diverted for this use. The largest constraint to water reuse in food processing operations is the concern over possible food safety issues arising from possible retention of pathogenic microorganisms in the recycled water. This problem can be prevented through disinfection, using chlorine, hypochlorite, ozone, ultraviolet radiation, or a combination of these. However, it must be ensured that the expense of the disinfection process does not negate the savings realized through water reuse.

Much of the water use in the food processing industry is non-consumptive (IQoyer, 1991), Le., the water emerges from the process as a waste, usually laden with undesirable materials, after use in cleaning or other operations. Hence, measures designed to minimize the inclusion of organic matter and other contaminants with the wastewater should be strongly linked to water conservation efforts. Such measures include dry cleaning of equipment and the process floor, the strategic placement of containers to catch spills, and even the use of sophisticated equipment to physically recover solids from the wastewater stream. Unless the quantity of contaminants entering the wastewater stream is reduced, water conservation may actually make it more difficult for a company to achieve compliance with wastewater regulations. This is because decreasing water use without reducing the mass of organic material lost to the wastewater will result in a waste of higher concentration. In some jurisdictions effluent regulations are based on concentration; reducing water use may actually push a company out of or further from compliance. However, when regulations are

111-5

based on the mass loading (the product of concentration and flow), this penalty does not occur. Hence, it would appear that mass-based effluent limits would be more effective in encouraging water conservation programs. Nevertheless, it is desirable to encourage the reduction of soluble and particulate matter in the waste stream. As pointed out earlier, material that is conveyed by the sewer system to the municipal wastewater treatment system is converted into another waste material, municipal biosolids, that must be disposed or managed. Furthermore, materials that are not combined with the wastewater can more readily be collected, segregated, and recovered.

Poultry processing operations provide a good example of this concept. Wastewater generated in a poultry plant typically reaches as much as 10 gallons/bird, and about 27% of a bird's live weight is lost as inedible by-product. The different residual components, i.e. offal (viscera), feathers, heads, and blood, if separated and handled properly, can be converted into a high-quality pet food. However, material lost to the wastewater goes through the dissolved air flotation (DAF) process, which is designed to remove fats and proteins from the wastewater prior to discharge. The fats and proteins are recovered in a sludge which typically contains 70% moisture, 15% protein, and 15% fat. Chemical inputs are required to float the material in the DAF system. The DAF sludge is more difficult and costly to handle and process than the segregated wastes, and the resulting product typically is suitable only as livestock or poultry feed, with a much lower value than pet food. Hence, efforts to maximize the recovery of by-products prior to DAF treatment, even with the use of sophistical physical separation devices for solids recovery, should be economically justifiable. Addltional benefits of reducing the amount of by-product lost with the wastewater stream is that a corresponding reduction in the operating costs of the DAF system and other pretreatment units as well as a reduction in the volume of DAF sludge.

Due to its high moisture content and the resulting cost of handling and processing, DAF sludge is considered a problematic material, even though essentially all of it is converted into feeds. In fact, as effluent regulations become more stringent and processing plants have to meet lower limits on wastewater-borne solids, DAF pretreatment units are being operated to achieve higher solids capture efficiencies, resulting in higher sludge generation rates. Furthermore, with the increasing focus of renderers on higher-value products, i s . pet-food grade rather than livestock feed grade, the already miniscule value of DAF sludge has degraded even further, as the metals that are sometimes used to effect flotation are unacceptable in a pet food product. Hence alternatives to the dissolved air flotation process should be considered. For example, given the rapid and recent developments in microscreen and membrane separation technology, it is possible that these would now be economical alternatives to the DAF process. The material recovered through a microscreen or membrane process would be more concentrated and less bulky (without the entrained air) compared to DAF sludge, and could be more readily utilized in downstream recovery processes. In fact, membrane processes could eventually prove an important tool for water reuse, wastewater treatment, and solids recovery, and could be used to pre-concentrate the wastewater solids prior to drying, bioconversion, or other processing operations to obtain a final product. Another possibility would be on-site rendering of the DAF sludge, a process that is currently in the early stages of commercialization. Although such an approach does not necessarily reduce the quantity of DAF sludge that is produced, overall handling and transportation costs are reduced because the rendered product, has a better value than the DAF sludge, contains little or no moisture and is much lower in mass

111-6

and volume than the sludge. The product might still be suitable only for livestock or poultry feed, but could be more profitable due to reduced costs.

In food processing operations concerned with the processing of fruits and vegetables, a major waste stream consists of culls and debris separated from the raw material. While mechanical harvesting has obvious economic benefits due to the reduced need for manual harvesters, it also has a number of disadvantages, including (York and Bogardus, 1995):

Mechanical harvesting can cause more damage to the usable fruit or vegetable, such as bruising or breaking, or to fruit and nut trees.

Significant quantities of soil (and soil microbes) are harvested with the planted crop, which increases the amount of washing required.

Yields may be lower and in-plant waste may increase because immature or unripe fruits or vegetables are harvested along with usable crops.

Consequently, while the quantity of culls and debris can be significant, it can be substantially reduced if grading and cleaning of the produce is done on the field prior to transport to the processor. For example, devices that remove stems, sticks, leaves, and soil from the produce can be used. The produce can be graded on the field prior to transport. In some cases, a limited amount of in-field processing can even be done, e.g., shelling of peas. In this way, the culls, soil, and other debris are retained for reintroduction into the field soil or for other beneficial reuse at the point of origin. At the same time, the quantity of waste that is sent to the plant is reduced, in effect increasing transportation efficiency.

In the area of institutional food waste, a number of simple source reduction strategies are available. Due to the diversity of the operations that generate these wastes, however, not all may be effective or even practicable in a particular setting.

Retail food stores and foodservice operations should observe strict inventory control and proper storage conditions to ensure that any perishable stocks do not spoil or exceed their useful shelf lives. When possible, raw materials should be purchased in bulk to minimize packaging waste: however, products that might spoil should not be purchased in excessive quantities. Excess edible or unsaleable food can be donated to food banks or other charitable organizations. A reduction in food waste generated by elementary school children has been observed when lunch is preceded by recess (Getlinger e t aL, 1996). Cafeteria managers in public schools have reported that adopting an offer versus serve approach can be effective in reducing plate waste (US General Accounting Office, 1996). Essentially, this means that students are offered a number of food options, any of which they may decline, rather than being served a uniform fixed menu. Presumably this reduces plate waste by permitting students to select only the foods they like in quantities that they know they will be able to consume.

Foodservice operations should review their use of disposable materials such as food containers, utensils, napkins, and single-serving condiment packages. When feasible, disposable materials should be replaced with their reusable counterparts. The disposable

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materials generally become a component, and possibly a signlficant fraction, of the food waste stream, and their elimination would result in a corresponding reduction of that waste. The decision to eliminate the use of disposable materials, however, should take into account the cost of washing and laundering the reusable materials. If the use of disposable materials cannot be eliminated economically, then the selection of those made from recycled/recyclable materials should be considered. This selection is not always straightforward, as demonstrated by a study commissioned by McDonald's and conducted by the Stanford Research Institute (Hume, 1991), which showed that polystyrene was environmentally superior to paper for use in food containers: paper and paperboard used with food have to be coated, making them mixed materials that are nearly unrecyclable, while polystyrene consumes less energy than paper for its production, represents less weight and volume in landfills, and is recyclable. A preference should also be given to materials that are readily degradable or compostable, (e.g., cardboard or degradable plastic) so as not to limit recovery options for the waste stream. Other management approaches may also reduce the consumption of disposables. For example, the usage of paper napkins can be reduced by placing the dispensers on a central counter rather than on the individual dining tables; many drinks are available on tap which reduces the usage and handling of recyclable cans and bottles.

Institutional food waste also includes food preparation (lutchen) waste. An approach to minimizing this stream is to purchase and use more processed materials in bulk, rather than purchasing fresh produce. Examples of this approach include: the use of frozen, peeled, cut potatoes rather than fresh potatoes; chicken parts rather than whole dressed birds; or skinned, deboned chicken breasts rather than whole chicken breasts. This technique was used by the U.S. Antarctic Program to essentially eliminate waste vegetable material generated at McMurdo Station, Antarctica (National Science Foundation Office of Polar Programs, 1994). It might be argued that this approach merely allows the waste to be generated at another location, i.e. at the processing plant. However, a large integrated manufacturing plant would be more likely have an established waste collection and recovery system than a restaurant or even many large institutional food waste generators; hence, it is probably more efficient overall to allow the waste to be generated at the plant. "he institutional user must, of course, assess whether or not purchasing preprocessed material is economically justified. The preprocessed foods could be more expensive than their fresh or less processed counterparts, but would require less labor for preparation and cooking. However, quality and flavor may also be important considerations, especially at high-end foodservice establishments such as gourmet or upscale restaurants and hotels, and these factors could rule out the use of preprocessed foods.

Another possible opportunity for waste reduction/minimization concerns oil-water separation, both in food processing and in foodservice activities. While many food processing plants employ DAF systems to 'remove oily wastes from their wastewater, a number also use gravity-based separators, i.e., oil or grease traps. These traps are also used universally in the foodservice industry. Performance of these oil and grease capture devices, however, is impaired when the oil and water are emulsified. Many cleaning chemicals are precisely formulated to degrease surfaces and remove soils by their emulsifying action. The use of non-persistent emulsifiers may improve the performance of oil and grease traps in such establishments, particularly those when the trap has sufficient capacity to hold the wastewater for the amount of time required for the emulsifier to break down. The Naval

111-8

Civil Engineering Laboratory has recommended a number of formulations incorporating non-persistent emulsifiers for cleaning bilges, holding tanks, and other oil-soiled structures onboard ships or onshore. Selection of non-persistent emulsifying degreasers makes oil- water separation more effective, reducing the volume of petroleum-contaminated hazardous waste that must be disposed of (Torres, 1991). A similar examination of industrial cleaners used in food processing and institutional food operations could be conducted, and may result in improved oil-water separation, better oil recovery, higher quality of recovered oil (potentially usable for biofuel production), and improved quality of the grease trap effluent.

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111.4. WASTE RECOVERY AND UTILIZATION OPPORTUNITIES

Waste recovery and utilization opportunities are enumerated and discussed here based on the hierarchy listed in Section I11 2.2. In this manner, technologies and opportunities that would provide the greatest potential benefit are presented first. Conversely, those technologies and opportunities are also the most likely to require the greatest amount of research and development work prior to implementation. This suggests a phased approach to a comprehensive, statewide food waste recovery program. The initial phases of such a program would focus on capturing the maximum amount of waste and utilizing it for low-end products. In the meantime, research and development on the utilization of these wastes for more desirable products would be undertaken. As the technologies are developed and made end-user ready, they would be transferred to industry to displace the low-end products or possibly to absorb additional amounts of waste.

In examining the possible uses of food-based residuals and waste, it is useful to consider the principal constituents of these wastes. For example, meat, poultry and seafood processing wastes predominantly contain protein and fats. Wastes from bakery operations contain a combination of simple and complex carbohydrates, while grains left over from alcoholic beverage production are depleted in their carbohydrate content and relatively enriched in fiber and protein. Fruit and vegetable processing wastes contain cellulosic materials, and dairy wastes contain a combination of protein, fats, and carbohydrates. Institutional food waste contains a combination of all the different food components, and may therefore provide a balanced medium for the culture of microorganisms. However, the composition of institutional food waste could be highly variable, which could complicate its use in an industrial fermentation process. An additional problem with institutional food waste is the requirements for sterilization may be more rigorous compared to other waste materials.

111.4.1. BIOTECHNOLOGICAL OPPORTUNITIES

The food industry may be considered in many aspects as the largest, oldest, and most potentially valuable form of biotechnology (IGoyer, 1991). The application of biotechnology to the modification of food components, to new methods for the production of food and food components, as well as to modern methods of food analysis has risen in importance in the food industry. It is not surprising, therefore, that biotechnology has found application and exhibits great potential in the recovery of food processing residuals and institutional food wastes. In this way, food wastes could be utilized by modifying them into upgraded materials of higher value than the waste itself, or into entirely new products, via microbially- or enzyme-mediated processes. In particular, the production of completely different products from the waste through the application of biotechnology has gained great attention.

Advances in biotechnology have opened a wide horizon for the utilization of organic materials. By engineering microorganisms and biochemical manufacturing processes, it is possible to achieve bioconversion of a wide array of biogenic materials into usable products.

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Institutional food wastes and many food processing residuals can certainly supply the carbon and nutrients converted by microorganisms into useful products; hence, biotechnological applications deserve extensive examination in this report. While it would not be practical to exhaustively enumerate and discuss in detail all potential products that can be derived from industrial fermentation, Table 111.4.1 contains a listing of some widely manufactured products.

Industrial fermentation processes basically proceed by supplying a microbial culture with substrate (i.e., carbon source usually carbohydrate) and nutrients (principally nitrogen) and the environmental conditions required for its growth; then harvesting the culture and recovering the desired product from the culture melum or from the microbial cells. Oftentimes these processes are able to supplant traditional chemical synthesis, frequently displacing raw materials derived from non-renewable resources, at a much reduced cost. For example, production of riboflavin (vitamin BJ by industrial fermentation using a genetically- modified Bacilltls saptdis costs about half compared to conventional synthesis from ribose sugars (Ondrey, 1998). Another biochemical process would reduce the retail price of ethyl lactate, an environmentally benign alternative to chlorinated solvents, from $1.60-$2.00/lb down to $0.85/lb (Parkinson, 1998). Materials commonly used to supply microbial carbon and nitrogen requirements in industrial fermentation processes are presented in Tables 111.4.2 and 111.4.3. Micronutrients and growth factors will have to be added to the growth medium, but the amounts of these are relatively minor compared to the carbon and nitrogen sources. It is interesting to note that a number of the feed materials listed in Tables 111.4.2 and 111.4.3 are in fact food processing by-products (e.g., molasses).

The compounds listed in the left column of Table 111.4.2 are all carbohydrates of relatively simple chemical structure. Indeed, with few exceptions, industrial fermentation processes essentially synthesize complex organic chemicals from simple carbohydrates. In order to broadly utilize food and food processing waste in industrial fermentation, therefore, it is necessary to convert the complex and polymeric carbohydrates that constitute most plant material into the simple carbohydrates needed for fermentation processes. This is accomplished via a process referred to as hydrolysis. Because polysaccharides are probably the most abundant waste materials available for recovery and conversion into useful products, extensive research has been done on their hydrolysis.

Hydrolysis can be achieved enzymatically or chemically (acid hydrolysis); a comparison of these two processes by Kosaric and Veleyudhan (1 991), whose analysis suggests enzyme hydrolysis is the preferable process, is presented in Table 111.4.4. Enzymatic processing of waste starch proceeds through the sequential application of a number of enzymes that ultimately converts it into maltose syrup or glucose syrup, and the use of thermophilic amylases permits thermal disruption of the starch grain and the enzymatic hydrolysis to occur simultaneously. Enzymatic degradation of cellulose, on the other hand, is hampered by its crystahne structure and the inclusion of other components that compose plant cell wall material. Typical agricultural wastes contain 38 - 42% cellulose, 31 - 34% hemicelluIose, 7 - 11% lignin, and 10 - 13% of other components (Gacesa and Hubble, 1991). Therefore cellulosic materials are normally disrupted by a variety of physical or chemical methods prior to enzyme treatmen,t. Hydrolysis of lactose, the major polysaccharide contained in dairy products, into its constituent sugars glucose and galactose

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Table 111.4.1 Selected Products Manufactured through Industrial Fermentation Processes.

Product Application

Antibiotics Treatment of infectious dseases Penicillin Streptomycin Tetracyclines Siderophores

Anticancer agents Cancer treatment

Steroids

Vitamins Food supplements

Treatment of inflammatory and allergic diseases

p-Carotene Riboflavin (Bz) Cyanobalamin @z)

Commodity chemicals Ethanol Acetone Butanol 2,S-Butanediol

Organic acids Acetic acid Citric acid Butyric acid Proprionic acid Lactic acid Gluconic acid Itaconic acid

Amino acids Glutamate Lysine Aspartate

Fuel/fuel additive, solvent Solvent Laquers, rayon, detergent, solvent Synthetic rubber

Food ad&tive/aciddant, plastics/polymers Food additive/aciddant, surfactant Plastics/polymers Plas tics/polymers Pharmaceutical and food additives Food and pharmaceutical additives Plastics/polymers, cosmetics ingredient

Food additive Food/feed additive Food, cosmetic and pharmaceutical additive

Enzymes Protease Lipase Glucose isomerase Xylanase Glucanase Phytase

Polysaccharides Xantham gum Dextran

Bioherbicides and biopesticides

B a d u s tburingiensis Insecticide

Specific chemical conversions Soaps and detergents, leather tanning Soaps and detergents Food processing Pulp bleaching Feed additive Feed additive

Food additives

Mtcrobial Fat Fuel or fuel additives Algal lipids

Single Cell Protein Feed ingredient

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Table 111.4.2 Carbon Sources Commonly Used in Industrial Fermentation Processes. Source: Atkinson, 1991.

Carbohydrate Source

Glucose Pure glucose monohydrate, hydrolyzed starch

Lactose Pure lactose, whey powder

Starch Barley, groundnut meal, oat flour, rye flour, soybean meal

Sucrose Beet molasses, cane molasses, crude brown sugar, pure white sugar

Table 111.4.3 Nitrogen Sources Commonly Used in Industrial Fermentation Processes. Source: Atkinson. 1991.

Nitrogen Source Nitrogen Content YO N by weight

Barley 1.5 - 2.0

Beet molasses 1.5 - 2.0

Cane molasses 1.5 - 2.0

Corn -steep liquor 4.5

Groundnut meal 8.0

Oat flour

Pharmamedia

Rye flour

1.5 - 2.0

8.0

1.5 - 2.0

Soybean meal 8.0

Whev Dowder 4.5

has also been accomplished through the use of galactosidase. Although the use of galactosidase was developed primarily to enhance the digestibility of dairy products for lactose-intolerant individuals, this process should be equally applicable to the processing of waste material derived from the dairy industry.

A strategy for utilizing carbohydrate-based food and food processing waste, therefore, is to hydrolyze them into simple sugars to be used as feedstock for the manufacture of value-added products through the application of downstream

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Table 111.4.4 Comparison of Enzymatic Hydrolysis and Acid Hydrolysis of Cellulosic Material Into Glucose. Source: Bisaria, 1991.

Factor Enzymatic hydrolysis Acid hydrolysis

Specificity Highly specific Nonspecific hydrolysis of cellulose; may also degrade lignin

Rate of hydrolysis

Reaction conditions

Effect on degree of polymerization

Catalyst requirement to achieve same degree of hydrolysis

Cost of catalysts

Side reactions

Yield of glucose

Low

Mild conditions: atmospheric pressure, temperature 40-60 "C, and pH 4.8-7.0 depending on the enzyme source

Slight decrease in degree of polymerization with appreciable weight loss

Very little compared to acid hydrolysis (approximately 1 0-5 time)

Not generally high, catalyst recovery required for costly chemicals

No side reaction, products of hydrolysis can be directly utilized for subsequent fermentation

Overall yield is high provided pretreatment is effective

High

Harsh conditions: high temperature and pressure, corrosion-resistant equipment required

Considerable depolymerization without appreciable weight loss

Extremely higher

High, approximately 50% of total cost, recovery/recycling of catalyst required for economic operation

Generally results in unwanted side products, e.g., furfural from hemicellulose

Overall yield is low due to degradation

biotechnological processes. Table 111.4.5 lists potential products derived from lignocellulosic materials and their applications and/or downstream products. A few of the more important bulk products or potential products will be discussed here. Discussion in succeeding sections will focus on specific considerations for particular applications of these products, other more specialized biotechnologxal products, opportunities applicable to specific waste materials, and non-biological processes.

Glucose is an easily fermentable sugar, and it remains one of the most sought-after products of enzymatic degradation of cellulosic materials. Glucose can serve as feedstock

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Table 111.4.5 Possible Downstream Products Derived From Cellulose, Hemicellulose, and L i p n via Biotechnological and Industrial Fermentation Processes. Source: Bisaria, 1991.

Material Possible Downstream Products

I. From cellulose

1. Glucose Chemicals

Ethanol 2,3,-butanediol Fructose (sweetener) Acetone/ butanol Energy (alcohol, AT") SCP- Protein concentrate

- Yeast glycan - Nucleic acids - Autolyzates

2. Cellobiose/cellodextrins Research chemicals

3. Ethanol

11. From hemicellulose

1. Xylose

Chemicals Solvents Beverages Biological energy (AT")

Ethanol Xylitol (sweetener)

2. Furfural and Chemicals and solvents (e.g., 2,3,-butanediol methyl ethyl ketone)

111. From lignin

1. Polymeric lignins Adhesive Dispersant Complexing agent Stabilizer Antioxidant Precipitant Defloculant Coagulant Pesticide carrier

2. Chemical intermediates Phenols Cresols Vanillin Vanillic acid Syringaldehyde Syringic acid Dimethyl sulfide Dimethyl sulfoxide

Petrochemical synthesis (via

Gasohe dlluent and octane

Food and feed

ethylene)

enhancer

SCP (Single cell protein)

Emulsion stabllizer Soil conditioner Rubber reinforcement Phenol-formaldehyde resin and

extender Urea-formaldehyde resin and

extender Polyurethane foam

Methyl mercaptan Ferulic acid Lignosulfonates (additives in

stabilizer, grindmg aids, and binders)

diesel fuel) Butanol-lignin slurry (furnace and

IV. From lignocellulose (untreated Edible mushrooms Methane (biogas) or pretreated) Animal feed Fertduer

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for the biochemical manufacture of a number of bulk and specialty chemicals, as listed in Table 111.4.5; hence, it is an important product in the hydrolysates of cellulosic materials. Fructose is an isomer of glucose, but is substantially sweeter. It is widely used in the manufacture of foods and beverages. Fructose is mostly manufactured from corn, whose starch content is hydrolyzed into glucose, which is then enzymatically converted into fructose using glucose isomerase. Thus fructose is commonly supplied as high-fructose corn syrup.

Ethanol can be produced from cellulosic residues by one of three major routes pisaria, 1991). In the conventional two-step process, cellulose is enzymatically hydrolyzed to glucose, which can subsequently be fermented into ethanol using yeasts (Succhharomyces) or bacteria (Zymomonus). The technology for fermentation of ethanol from yeast is well developed and can be used for cellulose hydrolysates provided the hydrolysates do not contain material inhibitory to the growth of the yeast. The single step process for conversion of cellulose into ethanol can be of two types depending on whether enzymes or bacteria are used. In the simultaneous saccharification and fermentation process, the saccharification of cellulose into glucose using cellulase enzymes and the subsequent fermentation of glucose into ethanol occur simultaneously in the same vessel. In processes employing bacteria, either a single cellulolytic ethanologen (monoculture fermentation) or two organisms, a cellulolytic organism and an ethanologen (co-culture fermentation) are used. Ethanol is used as fuel, an industrial solvent, with broad application in chemical synthesis, and as an oxygenate in gasoline.

Whereas the most research on the production of solvents through bioconversion of lignocellulosic material has focused on ethanol, other industrially important solvents can be produced from the hydrolysates of lignocellulosic substrates. Acetone and butanol can be produced from a variety of hexose and pentose sugars present in the hydrolysate of lignocellulosic substrates. The fermentative pathway for acetone and butanol production (which is more complicated than that for ethanol) is branched; hence, process conditions, specifically pH and substrate concentration, need to be closely controlled to ensure that a desirable product mix is obtained. 2,3-Butanediol can likewise be produced from a variety of carbohydrates, such as glucose, xylose, and disaccharides, present in the hydrolysates of cellulosic wastes.

Single cell protein (SCP) refers to microbial proteins derived from yeast, bacteria, molds, higher fungi, or algae, for use as animal feedstuffs or for direct inclusion in the human diet (Lee, 1991). The cultivation of microorganisms for food or feed has two main attractions. First, microorganisms grow at a much faster than animals or plants, potentially reducing the time required to grow a given mass of food. Second, a range of materials, including low-grade carbohydrate waste, can be used to produce SCP. However, the consumption of SCP as a &et component imposes particular requirements with respect to product safety and composition (Kroyer, 1991). The nutrient content and value of SCP must be considered in the development of diets that incorporate it. Specifically, the product should have a high protein content, as well as a suitable amino acid profile, ( i.e., contain high concentrations of nutritionally valuable essential amino acids). In general fungal protein compares well with most conventional foods, but is deficient in the sulfur amino acids. Microbial biomass also contains a high concentration of nucleic acids, which can cause gout- like symptoms in humans. The waste used to produce SCP must be free of toxic

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compounds such as metals and pesticides; otherwise, the product biomass would be unsuitable for food or feed use. The product must not be contaminated with other microorganisms, particularly pathogens. In effect, it is necessary to cultivate and harvest a monoculture, which means that sterilization procedures on the waste are necessary. All these steps are expensive; so in order to be economically viable, it is essential that the yields of protein and biomass be optimized. This requires that the substrate have a balanced nutritional profile, so that microbial growth is carbon-limited. Carbon-limited growth also helps prevent the formation of secondary metabolites that may be toxic (e.g., aflatoxins) or otherwise undesirable. The food quality and safety testing and standards requirements may be a limiting practical factor for the general application of a widespread method for the production of SCP from food industry or institutional food waste. Even if these constraints can be overcome, there is still the question of the acceptability of the biomass as food or feed. For food use, the biomass would require further processing to eliminate or modify flavors undesirable to consumers. Animals fed on microbial biomass could develop off- flavors in their meat that would make them unacceptable to consumers, thus limiting the use or requiring prior processing of the biomass for animal feed material.

In the case of proteinaceous waste materials, biotechnological opportunities are also available (Gacesa and Hubble, 1991), but these require further development. Enzymes which mediate the hydrolysis of proteins, i.e. proteolytic enzymes, have the ability to change the structure and hence modify the digestibility of protein materials. Proteolytic enzymes therefore offer the potential for upgrading protein wastes for use as animal feed or human food supplements. For example, alkali/enzyme treatment of hide trimmings has been shown to significantly reduce protein molecular weight and increase digestibility. A possible application of this technology in Georgia is in the poultry processing industry, where enzymes could be used to convert feathers into a high-grade, highly digestible feed product rather than being rendered into feather meal. These enzymes might also be useful in conjunction with SCP production, to modify the proteins contained in the microbial biomass. Proteolytic enzymes can also be used to recover high-grade fat or oil from a mixed waste containing protein and oil.

While industrial fermentation processes have trahtionally been performed in liquid culture, solid substrate fermentation is an alternative that should be examined for the recovery of food waste and food processing residuals. Solid fermentation processes generally produce lower yields and proceed at a slower rate compared to liquid processes, but require less capital and energy inputs and are especially suitable for growing mixed microbial cultures where symbiosis stimulates better growth and productivity. Hence, solid state fermentation has the advantages of high fermenter volumetric productivity and reduced product recovery expenses, pollution problems, and total cost of production. Disadvantages, however, include the limited types of organisms that can grow at reduced water activities (fungi, some yeasts, and some bacteria and streptomycetes), technical problems in controlling heat generated during fermentation, low product yield, slow fermentation rates, and difficulties in reliable process monitoring and control (F'aredes- Lopez and Alpuche-Solis, 1991). Solid substrate fermentation is used in a number of traditional processes for the production of food (mold-ripened cheeses, tempeh), feed (silage), and fertilizor/soil amendment (compost), and can be applied to obtain other products such as ethanol, enzymes, and specialty biochemicals. Vandenberghe et al. (2000),

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for example, have reported on solid-state fermentation of selected agro-industrial residues for the production of citric acid by Aspergills niger.

An alternative biorecovery process for food processing residuals and institutional food waste is anaerobic digestion. The anaerobic digestion process entails the hydrolysis and solubilization of the complex organic material in the waste, followed by fermentation into volatile fatty acids (VFAs) by acidogenic bacteria, and conversion of the VFAs into methane by methanogens. Methane is used as a fuel and is not considered as desirable as ethanol or other products; hence, it is consigned a much lower value. In addition, stabilization of the waste is achieved, and the residual sludge can be used as a fertilizer or compost. Aerobic biotreaunent processes likewise achieve stabilization of the waste and produce biomass. While these generally do not generate usable products, at least on an economic scale, the incorporation into animal feed of waste activated sludge from wastewater pretreatment plants in food processing establishments has been reported (IGoyer, 1991).

111.4.2. RECOVERY FOR HUMAN USES

Food processing wastes can be recovered through a variety of processing techniques to obtain a wide range of products for human use, including food and bulk and specialty chemicals. As discussed above, technologies that utilize microbial and enzymatic techniques to transform the waste, particularly into entirely products entirely different from the original waste, have gained greatly in importance.

Carbohydrate and cellulosic food waste are versatile raw materials, and once hydrolyzed can be used for the production of a broad range of chemicals. No attempt will be made to exhaustively list all potential products, but instead, a number of products that have been obtained by fermentation and/or enzymatic processing of food wastes will be enumerated here briefly. Citric acid, a food additive, acidulant and industrial chemical, can be produced by liquid or solid fungal culture of A@e@hh.r n i p . Gibberelltc acid can likewise be produced by Aspergills niger fermentation of molasses, whey, sugar beet waste, or fruit pomace (Cihangir and Aksoza, 1997). Amino acid production from food wastes using Corynebactem~mglzltamiczlm has in fact been a major research thrust at the UGA Department of Biological and Agricultural Engineering. Production of fat from sweet potato processing wastes and from molasses has been performed by fermentation with microorganisms from the Lipomyces species (IGoyer, 1991). Production of enzymes from cellulosic and lignocellulosic wastes via solid state fermentation has been reported (ICrishna and Chandrasekaran, 1995; Gupte and Madamwar, 1997). The possibility of producing antibiotics from plant-derived food processing wastes has also been described. Another interesting approach is to use semi-solid or submerged fermentation processes to produce microbial biocides. Wastes from the brewing, grain, and bakery industries, have been used to produce Bacillzls thuringzensis endotoxins to obtain bacterial insecticides (ICroyer, 1991), while a hebicidal compound can be produced by growing Saccharothrix sp. ST-888 on vegetable juice medium (Takahashi e t al., 1995).

Waste beverage from soft drinks packaging operations is another potentially fermentable food processing residual. The waste beverage contains a substantial amount of fermentable sugar, and may also be high in inorganic nutrients such as phosphorus. However, the pH of the waste would typically be low, as the beverages are acidulated using

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phosphoric, citric, or other food grade acids as a means of preventing microbial growth. Nevertheless, simple pH adjustment and nutrient supplementation, the waste beverage may be readily usable as a fermentation medium, and as such can serve as raw material for biofuel or chemical production. Research into this subject has likewise been performed at the UGA Department of Biological and Agricultural Engineering.

Cellulosic food and food processing residuals can also be processed by non- biological means to recover usable chemical products. Pecan nut shell flour from a Georgia manufacturer is currently used as a filler in plastic composite product, and studies have been conducted on the use of pecan and peanut shell flour as fillers in polyethylene composites (Raj et al., 1992a, b). Currently, a large amount of peanut shell hulls is used for compost manufacture, and the diversion of some of that waste into plastics production could be investigated.

Activated carbon has been produced from brewery residues (Hayashi et al., 2000), coconut (Tam and Antal, 1999), macadamia nut (Dai and Antal, 1999; Tam and Antal, 1999) and pecan nut (U.S. Department of Agriculture Agricultural Research Service, 1996). shells, and cherry stones (Lussier et al., 1994). Food processing residues of a similar nature are available in Georgia, e.g., pecan nut shells and peach pits, and could likewise be used for activated carbon production.

Chemical recovery of specialty chemicals from specific wastes can also be performed. For example, carotenoids can be extracted from carrot trimmings by traditional solvent extraction and by supercritical fluid extraction (Barth et al., 1995), while tartaric acid can be recovered from fruit juice industry wastes by electrodialysis (Andres et ai, 1997), and the anticancer compounds resveratrol and ellagic acid can be extracted from grape pomace (U.S. Department of Agriculture Agricultural Research Service, 1997). Fruit pomace and peels can also be processed into a source of dtetary fiber (Gourgue e t al., 1992; U.S. Department of Agriculture Agricultural Research Service, 1997). Oils can be extracted from the pits of peaches, apricots, cherries, nectarines, and plums (Kame1 and Kakuda, 1992).

Meat, poultry, and seafood processing residuals, even though they are essentially completely recovered, represent a very large volume of waste, hence the examination of alternative uses for these materials is worthwhile. Typically meat and poultry processing residuals are rendered into animal feed. Alternative uses may be possible, however, with the development and application of the needed technology, and with suitable measures for segregation, handling, and storage of the waste. Blood can be hydrolyzed enzymatically, with the iron-rich heme fraction used as a dietary additive or an animal feed supplement (Kroyer, 1991), and the globin fraction used as an ingredient in processed meat products (Liu e t al., 1996) or as a protein source in bacterial growth media (Hazarika, 1994). Other biotechnological recovery processes include the isolation of chitin from seafood waste (Gagne and Simpson, 1993; Zakaria et al., 1997; Synowiecki and A1 Khateeb, 2000), and of collagen from fish processing wastes (Nagai, 2000). A process to convert poultry feathers into a fiber that can be combined with other natural or synthetic fibers to manufacture new products has been developed by the U.S. Department of Agriculture Agricultural Research Service, and is in the early stages of commercialization (Comis, 1998, 2000). The use of defatted poultry feathers as insulation material has been investigated by the University of Georgia Biological and Agricultural Engineering Department. Other potential physico-

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chemical recovery products from animal processing wastes include collagen from eggshell wastes (IGnney, 1999), and amino acid-based surfactants from a variety of industrial protein wastes @a et al., 1996).

Vegetable oil waste is generated in food processing plants with frying operations, in foodservice establishments, and in vegetable oil mills. Animal fats, on the other hand, are part of the waste from slaughter operations. Disposal of this waste stream has been a particular problem in foodservice operations, as industrial establishments are typically able to arrange for its recovery through a renderer, although the recovery of higher-end products from the industrial streams should be considered also. Although there is a limited number of microorganisms, mostly fungi, which are effective in the conversion of oils into usable products, the possibility of recovery through biotechnology is nevertheless available. One possible product is carotene, which is a widely used pigment and an important nutrient, being a precursor of vitamin A (Atkinson and Mavituna, 1983). Another potential product is omega-3 fatty acids, polyunsaturated fatty acids which are traditionally obtained from fish or marine oils and which provide beneficial health effects (Bajpai et al., 1992). A third possibility is lipase, which is used as an additive in food and detergent formulations (Miranda e t al., 1999). All of these are products can be obtained by fermentation using filamentous fungi in an oil-containing medium.

A non-biological alternative for recovery of waste vegetable oil is its use for rhe production of plastics, including polyurethane foam (Nakamura and Nishimura, 1993; Feil, 1995). The resulting plastics would be biodegradable and possibly compostable. Vegetable oils can also be used as part of a lubricant formulation (Patil et al., 1998).

Recovery of dairy industry waste, particularly whey, has attracted great attention. Table 111.4.6 lists some products recoverable from whey, including some that can be manufactured via biotechnological routes. Nevertheless, the cost of converting whey to a by-product may be unjustifiable economically, as the supply of whey far exceeds the demand for products that are derived from it. Little or no new technology for producing additional whey products has been created in the last several years, although such technology is needed to move whey fractions into the general marketplace (Council for Agricultural Science and Technology, 1995).

111.4.3. RECOVERY FOR ENERGY

The recovery of energy from food processing residuals can be accomplished by processing the material into a commercial-grade fuel, and one potential product that has received much attention is fuel-grade ethanol. The production of ethanol from food processing waste via enzymatic hydrolysis and fermentation may represent a significant opportunity given the current initiative to reduce dependence on fossil fuel and to eliminate the use of methyl tert-butyl ether as a fuel oxygenate. Alternatively, there has also been developed a process that converts cellulosic waste into mixed alcohols (Holtzapple e t al., 1999), which in principle could be used as a fuel or fuel additive in a manner similar to ethanol. Waste materials containing carbohydrates and cellulose would be amenable to recovery via the production of ethanol or mixed alcohols. These materials include bakery and grain processing waste, fruit and vegetable processing residuals, and nut and oilseed

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Table 111.4.6 Potential Products From the Recovery and Processing of Whey. Adopted from Kosaric and Velayudhan, 1991.

Raw Material Process Products Potential Downstream Products

Whey Pasteurization Whey cream Whey butter

Pasteurized sweet Whey drinks whey soups

Cheese

Concentration Whey protein Protein hydrolyzates Cheese Processed cheese, cheese spreads Feed Bakery products

Dried whey soups Processed cheese, cheese spreads Feed Bakery products Candy

Plain condensed soups whey Processed cheese, cheese spreads

Feed Bakery products Candy

Sweetened Bakery products condensed whev Candv

Lactose Candy Infant foods Hydrolyzed lactose syrup Pills Penicillin

Fermentation Riboflavin Feed Riboflavin concentrates Butvl alcohol. acetone

Ethyl alcohol Spirit vinegar

Lactic acid Food acidulant Resins, coatings Tanning Acrylic plastic

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hulls. In a few cases, the residual may be directly fermentable, i.e., without the need for prior hydrolysis, as in the case of soft drinks bottling waste.

Waste vegetable oil is another potential fuel resource. Chemical conversion by transfesterification results in biodiesel, which as its name indicates is a biobased alternative to fossil-based dmel fuel (Reed e t al., 1992; Srivastava and Prasad, 2000). The oil can also be blended directly at controlled levels with diesel fuel, and the blended product used to power diesel engines (Ozaktas, 2000).

Methane production through anaerobic digestion provides an alternative route to energy/fuel production from food waste. A wide variety of food processing residuals have proven treatable via anaerobic digestion, including wastewaters from sugar refining, potato processing, dairy, brewery, distillery, and fruit and vegetable processing operations (ISroyer, 1991). From a biochemical perspective, methane production has a number of advantages over ethanol production. Whereas in ethanol fermentation the substrate carbon is converted into ethanol and carbon dioxide in a 1:l ratio (Gottschalk, 1986), in anaerobic digestion that ratio for methane and carbon dioxide is 3:2 (Kosaric and Velikonja, 1995). Methane has the highest molar heating value of any organic compound, a consequence of its being the most highly reduced organic compound. Furthermore, that heating value is available at a high temperature, i.e., methane has a high combustion temperature, and is consequently suitable for a wide range of applications, e.g. power or steam generation. In effect, the recovery of energy from food waste can potentially be accomplished mere efficiently via methanogenic digestion than by alcohol production. Methane is generally not considered as desirable a product as ethanol; hence, it is much lower in value. In many cases, the biogas obtained from anaerobic digestion is used to supply heat to the dlgester. High temperatures are not needed for this purpose; however, the methane could be better used elsewhere if low temperature waste heat were instead used for digester heating (Iranpour etal., 1999).

Energy can also be derived from food waste by direct firing, Le., incineration with heat recovery. In addltion to producing energy from the waste material, a substantial reduction in waste volume is reallzed, i.e., the quantity of the residual ash is much less than that of the original waste material, so that the material that must undergo final disposal is substantially reduced. For this alternative to be feasible, however, the waste material should have a significant heating value, and the moisture content should be low to minimize the amount of energy lost as latent heat. A candidate material for this approach was encountered by Georgia Environmental Partnership personnel who conducted a site assessment and follow-up studies at a vegetable oil refiner. In the refining process, bleaching clay is used to decolorize and deodorize the oil. The oil-saturated spent clay could potentially be used as boiler fuel, replacing a portion of the plant's natural gas requirement. At the same time, the combustion process would reduce the mass of the spent clay by 50%, and effect a corresponding reduction in waste disposal charges.

111.4.4. RECOVERY FOR ANIMAL USES

Recovery of food-based waste for animal uses is currently practiced for a wide variety of materials. As reported in Part 11, residuals from the meat and poultry industry, from seafoods processing, and from the bakery and grain industries are utilized as animal feed. The potential exists in the meat and poultry industries, however, to divert a larger

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amount of their residuals to the production of high-value pet food rather than less expensive livestock and animal feed, through improved waste collection, segregation, and handling practices. Another potential market is for aquaculture, as Georgia's aquaculture industry appears to be growing and two catfish processing plants are planning to begin operations in the next few years, and rendered meat and poultry by-products have proven viable ingredients for aquaculture diets (El Sayed, 1999; Bureau et al., 2000). The use of alternative processing methods, e.g., enzymatic conversion, could also result in products with higher value compared to traditional processing methods. Hides and feathers, for example, could be converted enzymatically into more digestible feed materials. On the other hand, much of the waste from bakery and grain products operations would be readily amenable to fermentation processes, and so could be diverted to recovery for human uses.

Chicken eggshells are a poultry processing residual that may be under-utilized. Calcium, a principal component of eggshells, is an essential nutrient, so it appears logical to investigate the use of eggshell waste as an animal feed ingredient. The utilization of eggshells as a calcium source was evaluated in piglets by Schaafsma and Beelen (1999). Eggshells contain 38% calcium, whereas calcium carbonate contains 40%. The digestibility of the calcium in the eggshells, however, was superior; eggshell calcium did not interfere with the digestibility of magnesium and crude fat. Hence eggshells were a viable calcium source for piglets. Furthermore, due to the great similarities in gastro-intestinal anatomy, physiology, and metabolism between pigs and humans, these results suggests that chicken eggshells may be a viable calcium source for humans, either as a dietary supplement or as additives in dairy and soy foods. However, due to the low price of industrial lime ($0.03/lb listed in Chemical Market Reporter, 26, May 2000) and the small amounts of calcium required animal diets, the use of eggshells to supply calcium in animal feed rations is not economically attractive.

In addition to meat processing, bakery, and grain processing wastes, other under- utilized food processing residuals could be diverted to animal feed production. Fruit and vegetable waste products could be used in ruminant (cattle, sheep, goats, and other even- toed, hoofed herbivorous mammals with multi-chambered stomachs) and layer (chickens raised for egg production) diets. Gupta et al. (1993) performed nutritional analysis on 24 different vegetable waste products, including cabbage leaves, cabbage stems, carrot leaves, cauliflower leaves, cull beans, dehydrated pea waste, onion husk, pea pods, potato peel, radish leaves, tomato leaves, tomato skin, and tomato pomace. The wastes were generally fairly rich in protein, low in soluble carbohydrates, comparatively rich in soluble fiber, rich in calcium, but ranging from fair to poor in phosphorus. Zia et al. (1994) tested a number of fruit and vegetable residuals, namely orange waste, mango peel, mango stone, and carrot residue, in layer diets. Carrot residue at 80 g/kg diet resulted in improved egg production and size over the control diet, while diets containing orange waste and mango peel were comparable to the control. Mango stone, on the other hand, had an adverse effect on egg production and size. Meals produced from peach, apricot cherry, nectarine, and plum seeds can be used as animal feed, but only in limited amounts or with prior detoxification due to the presence of cyanogenic glycosides (Ihmel and Ibkuda, 1992). While these studies are not necessarily specific to the fruit and vegetable processing wastes generated in Georgia, they demonstrate that these residuals can be beneficially reused as animal feed ingredients provided that they are segregated to allow for recovery of specific components, and that the effect of these residuals on animal performance and quality is thoroughly tested. Since these types of waste are plentiful and under-utilized, and since animal raising is a major agricultural

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activity in the state, research to evaluate different fruit and vegetable residuals as animal feed ingredients should be undertaken.

Institutional food wastes, on the other hand, while potentially a rich and balanced nutritional source, have typically been used for composting. For this purpose, they require the addition of a bulking agent with a high carbon-to-nitrogen (C:N) ratio, such as wood chips, so that the volume of material to be composted would be around five time the volume of the food waste. An alternative would be to convert institutional food waste into animal feed. The use of institutional food waste, and indeed of any waste containing or contaminated with meat or meat-derived products (e.g., bakery products formulated with lard) for swine feed has not been allowed in Georgia since 1973 (Georgia Department of Agriculture, 1992; Selph, 2000). Prior to that, feeding of this waste to swine was permitted provided it was first cooked for one hour at 165 O F . However, some hog farmers used uncooked or improperly cooked waste, and a large outbreak of hog cholera, which ultimately cost the state $16 million, occurred. An additional problem with raising hogs exclusively or extensively on kitchen and table scraps, even if these are properly cooked, is that undesirable odors can develop in the meat due to the high animal fat content of the waste material.

The public and animal health risks involved in feeding uncooked plate waste to swine were evaluated by the U.S. Department of Agriculture (Centers for Epidemiology and Public Health, 1995a, b, c; Corso, 1997). Due to the high degree of similarity between the human and porcine gastro-intestinal systems, mentioned previously, public health risks arising form swine feeding are a particular concern. Plate waste includes various meat products that could be contaminated with the human pathogens Salmonella, Campylobacter, Tndznella, or Toxoplasma, as well as eggs and dairy products that could contain Salmonella or Campylobacter (Centers for Epidemiology and Public Health, 199513). In addition, institutional food waste could contain spoiled food or trimmings from raw meat, and these raw or undercooked items could be contaminated. If swine are fed uncooked food waste, the probability that at least one portion per year would contain Salmonella was essentially 100%; for Toxoplasma, Campylobacter, and T7i;chinella, the corresponding probabilities were 1 OO%, 1 OO%, and 37%, respectively. These risks are substantially reduced or eliminated if the food waste is cooked prior to feeding (Centers for Epidemiology and Public Health, 1995b). In animals other than pigs, which have a gastro-intestinal system that is very similar to that of humans, the public health risk is much lower. With respect to animal health, the risk of exposure of swine fed uncooked food waste to hog cholera virus is 6.7% annually. Hog cholera virus has been eliminated in the U.S., so it would be contained only in pork products from infected countries, but substantial amounts of uncooked pork products enter the U.S. illegally from countries where hog cholera exists. For foot-and-mouth disease, the annual risk is 4.1%. Foot and mouth disease virus can be present in a variety of meat and dairy products because the virus can infect any cloven-hoofed animal. Estimated risk of exposure to African swine fever virus or swine vesicular disease virus in the continental U.S. are 0.5% for each. Both of these dlseases are restricted to swine and are not found in as many countries as hog cholera and foot-and-mouth disease. However, both are hardy and could be present in any uncooked pork product.

Certain wastes may be fed to swine, e.g., dairy products and bakery products not containing lard, but the practice is subject to review on a case-to-case basis by the State Veterinarian at the Georgia Department of Agriculture Animal Industry Division (Selph,

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2000). Also, the feeding of cooked or processed institutional food wastes is not regulated for cattle or poultry, so that avenue for institutional food waste utilization remains open. However, recovered institutional food waste may not be as efficient a feed for these animals as compared to swine because their nutritional requirements and digestive systems differ greatly from the humans for whom the food was prepared.

In addition to preventing public and animal health problems, cooking could also be used to improve the storage and handling characteristics of the waste. However, cooked institutional waste alone would be unlikely to completely supply the nutritional requirements for livestock or poultry raising or for aquaculture, and would require blending with other feed ingredients to provide specific nutritional requirements, depending on the animal to be fed. Even for swine diets, research reported in the technical literature typically uses cooked food waste to substitutes for only a portion of the conventional feed ingredients. Westendorf e t al. (1998) used cooked food waste and in addition to corn and soybean meal as a diet for finishing pigs, and found it suitable for swine diets. In the work of Myer e t al. (1999), the wastes were minced, blended with a feed stock (soy hulls and wheat flour or soy hulls and ground corn) pelletized, and dried. The dried product was then blended with additional minced food waste and dried; this process was then repeated. The resulting products contained approximately 60% dried food waste, and feeding trials and carcass evaluation showed that the material was suitable for finishing pigs. I<elley and Walker (1999) used a dry extrusion process to produce animal feed from food waste, soybean hulls, and ground corn, and evaluated the efficiency of microbial destruction. They found that although the extrusion process is capable of reducing microbial counts, further optimization of the process to achieve this objective was necessary. These studies amply demonstrate that food waste is a suitable animal feed ingredient, provided it is processed prior to feeding to destroy human and animal pathogens that may contaminate the waste.

Biotechnological alternatives also exist to the cooking and rendering technologies that have been used to convert food waste into animal feed. Traditionally, ensilage has been used to convert green crops and cellulosic waste into animal feed (Paredes-Lopez and Zapuche-Solis, 1991). Ensilage is a controlled fermentation process, where the raw material, sometimes augmented with molasses to improve palatability and promote fermentation, undergoes partial conversion to lactic, butyric, propionic, and acetic acids. The ensiling process can be applied to a wide range of cellulose-rich food processing waste, e.g. fruit peels and pomaces and vegetable trimmings. Ensilage can also be performed on fish and seafood (Evers and Carroll, 1995; Lassen, 1995; Faid e t al., 1997), and poultry processing wastes (Alwan e t al., 1993; Lassen, 1995; Mahendraker et ul., 1995) to obtain animal feed.

Enzymatic processing of proteinaceous food wastes can also be performed to obtain animal feed products. Hydrolysis of poultry feathers by alkaline protenase followed by spray drying results in a powdered product containing 80% protein (Dalev, 1994). Proteolysis was similarly used to obtain protein hydrolysate from chicken heads (Surowka and Fik, 1992). Proteolytic enzymes can also be used to improve the digestibility of traditional feather meal (Shih, 1993).

Another approach for converting food waste into animal feed is through SCP production. This is possible even for aquaculture feeds, as demonstrated by Martin e t al. (1993), who used extracts of hydrolyzed fish offal and peat compost to culture the yeast

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Candida .utilis and used the biomass to cultivate rainbow trout. For animal feed purposes, however, solid substrate fermentation may be an attractive alternative as it may not always be necessary to separate the SCP from the substrate. SCP could be produced in this manner from cellulosic waste materials, e.g., fruit and vegetable trimmings, and the biomass generated would serve to enrich the protein content of the waste to as much as 20 or 30% while retaining some of its original nutritional components, e.g., crude fiber. The augmented waste could thus become suitable for use as animal feed. The activated sludge process, although traditionally thought of as process for wastewater treatment rather than recovery, essentially produces biomass from the organic constituents of wastewater. Since food processing wastewater typically is relatively free of toxic substances, the biomass produced from the activated sludge process may be suitable for animal feed. The suitability of waste activated sludge from the treatment of wastewaters from the brewing, dairy, citrus fruit and fruit canning, and meat packing industries as feed for different animals has been tested, with positive results (IGoyer, 1991).

Integrated management approaches for wastewater treatment have also been developed that include a combination of anaerobic digestion, aquaculture, or the cultivation of algae or vascular aquatic plants for feed production (J?olprasert, 1996). While this approach has become popular in some other countries, it may not be equally applicable in the U.S. Because food production and food processing may be organizationally integrated, there is often a considerable physical separation between these operations.

In addition to the bulk feed products discussed above, it should be noted that a number of products which are manufactured as human food supplements or medicinal products can also be used for the same purposes in animals. Livestock and poultry growers use antibiotics to control disease, and amino acids and other micronutrients to ensure that the animals receive nutritionally balanced diets; production of amino acids from food waste for animal feeding purposes has been an area of research at the UGA Department of Biological and Agricultural Engineering. Compared to their human-use counterparts, however, animal-use products are typically not purified or refined to the same extent. For example, carotene is typically manufactured by fungal culture. Carotenoids are endocellular products, and for animal feed the mycelia can be used directly after drying. However, for use as a food additive or supplement, the carotene must be extracted from the dried mycelia and deodorized prior to use. The point of this is that many products listed for human use above, particularly biotechnologcal products like antibiotics, food, and nutrients, are not necessarily limited to that market but can be diverted to animal use as well.

111.4.5. RECOVERY FOR SOIL CONDITIONERS OR FERTILIZER

The use of food-based waste as soil conditioners or fertilizers is considered the least desirable recovery option, as it is considered to generate less benefit than products intended for either human or animal use. Further research to quantify the benefits of composting and land application are needed, however, as these do not appear to be fully appreciated in industry and agriculture. Composting and land application nevertheless avoid the environmental cost of waste disposal, and are probably the easiest recovery option to implement, hence they should be practiced when feasible and when other, more beneficial uses are not possible.

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Recovery of fertilizer values in food processing residuals or institutional food waste is accomplished either through composting or through land application. Composting is applied to solid and semi-solid waste, and has the advantage of providing a product that is easily transported and has commercial value. Like any microbial process, composung requires that the nutrient content of the material be suitable for microbial degradation. Consequently, materials with an excess of nutrients, particularly nitrogen, require the addition of a bulking agent that has a high C:N ratio, e.g., wood chips. Conversely, materials lacking in nitrogen need to be augmented with a nitrogen source to allow composting to proceed. The nitrogen source usually supplies moisture to the compost mix as well, since typical bulking agents are relatively dry. The need to achieve a balanced nutritional profile in the pre-compost opens many opportunities for waste complementation in composting. For example, the food waste-composting program operated by the Georgia Department of Corrections utilizes yard waste and ground cardboard from the local community as bulking agent (Allen, 1994; Georgia Department of Community Affairs, 1998). Other than institutional food waste, potential nitrogen/moisture sources generated in food processing operations include dairy waste, waste beverages and juices, and fruit pomace. Another possibility is to use high-strength or pre-concentrated wastewaters to supply moisture and/or nitrogen to the compost mix. ERTH Food, on the other hand, uses peanut hulls as bulking agent to produce commercial compost from municipal wastewater treatment biosolids (Icing, 2000); other nut and seed hulls could be used for the same purpose. Wastes containing large quantities of fats and oils are not recommended for composting, however, due to the potential for attracting vermin.

Vermicomposting, where earthworms are used to achieve bioconversion, is emerging as an alternative to traditional composting. Currently vermicomposting is used in Georgia for the stabilization of a limited quantity of municipal biosolids, but it is potentially usable for a wide range of materials of fruit and vegetable origin, including waste vegetable oil. Products of vermicomposting are the worm castings, which are harvested and used as soil amendment, and the worms themselves, which can be processed into a high-protein feed ingredient or used as bait in sport fishing.

In contrast to composting, land application, is more often used for industrial process wastewater, and often is restricted to a pre-selected site designed to absorb the wastewater and the nutrients it contains, to prevent overland flow into adjoining properties, and to prevent contamination of surface and ground waters. The operation of a land application site requires that a management plan to harvest and remove any crop grown on the site be implemented. Otherwise, the plants which utilize the nutrients will eventually die and decay on the site, and return the nutrients on the soil, limiting the nutrient uptake capacity of the site. Ideally, the crop produced should have some economic value and help recover part of the cost of treatment. It should also be pointed out that the site on which the waste will be applied would have a limited assimilation capacity, depending on the type of soil and on the crop to be planted and harvested. Thus, depending on the quantity and strength of the wastewater, a large land area may be required to handle the waste. Land application has been examined as an alternative for the recovery of oily food wastes (Plante and Voroney, 1998). The oily waste was found to have been 40% mineralized after four weeks under field conditions, and to provide potential agronomic benefits by increasing the soil microbial biomass and improving soil structure through increased aggregate stability.

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A technology that has been gaining use recently is the application of macrophytes (vascular aquatic plants) to wastewater treatment. This process is conducted in an artificial wetland, where aquatic plants and microorganisms are provided the opportunity to utilize the nutrients and organic matter in the wastewater. Again, there is the opportunity to harvest a crop, albeit of considerably less value than that produced in wastewater land application systems, which could potentially used for compost or animal feed.

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111.5. BARRIERS TO WASTE REDUCTION AND RECOVERY

Different issues that might hinder the adoption of waste reduction and recovery technology in industry are discussed in this section, and categorized by the nature of the constraint. Techno-economic and technology delivery issues are concerned with the development, economic feasibility, and transfer of technologies for waste reduction and recovery. Logistic issues are concerned primarily with the practicability of the collection and segregation of specific wastes. The discussion on environmental and public health issues discusses potential impacts and constraints with respect to environmental quality and human health. Finally, regulatory barriers to waste reduction and recovery are discussed.

111.5.1. TECHNO-ECONOMIC AND TECHNOLOGY DELIVERY ISSUES

One of the barriers cited by York and Bogardus (1991) to increased reuse and recycling is the lack of information on potential or ongoing programs and opportunities. An important component of the state's waste reduction initiatives is information dissemination to industry through different media and in different forums. The current technical assistance and technology transfer programs undertaken jointly by the Pollution Prevention Assistance Division, the University of Georgia, and Georgia Tech appear to have been effective tools for disseminating information on waste reduction, utilization, and treatment, and support of these should be continued. The approach of providing on-site services for the assessment of waste reduction, treatment, and utilization opportunities seems to have been particularly effective, and should be continued if not expanded. A related issue is the lack of information on the overall benefits of waste reduction. In many organizations, the true cost of the waste being generated is not realized, hence, from the viewpoint of the managers, there is little incentive to undertake a waste reduction program. Again the approach of providmg on-site technical assistance seems to be the most effective for disseminating such information to manufacturers. Training on full-cost accounting techniques would also be helpful, to allow manufacturers to accurately assess the true cost of a waste stream.

Although great advances have been made in biotechnology in recent years, commercialization of these processes has proceeded at a slower pace. To some extent, critical technologies are not yet fully developed. In particular, the efficiency and yield of the hydrolysis process for lignocelluosic substrates requires further improvement and optimization before it can be commercially attractive (National Research Council Committee on Biobased Industrial Products, 2000). Another reason, particularly for products where alternative petrochemical productior, methods are available, is a political and economic framework which supports extremely low petroleum prices and does not charge manufacturers fully for the environmental cost of their effluents (Bailey, 1995). Regardless of the cause, however, industries may consequently be wary of adopting innovative biotechnologies, and may require strong technical support from the state and from academe, either through consulting, training, or demonstration projects, before they are able to do so. Despite the technological advances, industrial fermentation processes remain relatively complex. Tight process monitoring and control are required, particularly when the desired product is a secondary metabolite, e.g., an antibiotic, io ensure optimal conversion and yield. The product is typically obtained at a dilute concentration in a medlum containing microbial

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cells, metabolic by-products, and residual substrate and nutrients, and separation and purification of the product can entail technologically complex operations that are energy and capital intensive. Consequently, an initiative to broaden the recovery of residuals for chemical production through biotechnologcal processes would require strong support in the form of technical assistance and technology transfer. Nevertheless, the shift to biobased production systems is widely viewed both as desirable and eventually inevitable (Natural Research Council Committee on Biobased Industrial Products, 2000), and it has been suggested that the chemical sector will in the future use ethanol as the two-carbon (C2), lactic acid as the C3, succinic acid as the C4, and citric acid as the C6 feedstocks of the chemical manufacturing sector, in place of their petrochemical counterparts (I+ullo, 1999).

While the residuals generated by the meat and poultry processing industry represent a sizeable volume, these are essentially utilized for animal feed production. This is partly a product of the tight vertical integration in the industry, where the poultry growers, processors, renderers, and feed millers may be owned or very closely affiliated to a single corporation. While this system has enabled the efficient capture and processing of residuals, it also serves as a potential barrier to the introduction of technologies that would divert the residuals to the manufacture of other, higher valued products. Animal feed is a major input to the production of their final product, so the poultry companies may be reluctant to relinquish or reduce their rendering activities because doing so would further reduce the little control they may have over feed prices. These companies also have substantial investments in rendering and feed milling plants, which they would want to safeguard. If a product is of sufficiently higher value and entails little influx of new capital, then it could readily be adopted. For example, high-grade pet food has a higher value than animal feed, and can be produced in the same rendering operation provided proper handling of the raw material is practiced and some modifications are made to the process parameters. Consequently, some rendering plants have shifted their product mix to include or increase the amount of pet food manufactured. However, when substantial new investments may be required, more resistance to the adoption of a new technologies or new products could be encountered.

The marketing and economics of chemical products, particularly industrial fermentation products, is also an issue that must be dealt with. Table 111.5.1 lists prices of selected bulk chemicals that can be manufactured from residual materials, as potential inlcators of the value that can be recovered through chemical manufacture. A number of the items listed are commodity chemicals, such as acetone, ethanol, acetic acid, and butanol. P-Carotene, on the other hand, is obviously a high value, low volume specialty chemical. Potential biobased products from food residuals clearly span a wide range in terms of price/va!ue and market volume. Bulk prices for traditional food processing residual-derived products or products that compete with them, on the other hand, are listed in Table 111.5.2. The hghest values here appear correlated to the protein content (65% for fishmeal). In comparison, chemicals typically fetch much higher unit prices. However, a comparison of unit prices alone is insufficient to gauge the economic potential of chemical production from food residuals vis-a-vis products traditionally obtained from this material. To further examine the potential value of food processing residuals as chemical manufacturing feedstocks, the case of a specific common fermentation product, ethanol is discussed here. Of the 1.6 billion gallons of ethanol production capacity, only 30 million gallons, less than 0.2%, is based on substrates other than corn (Cooper e t ul., 1999). In 1999, corn was relatively expensive, and about two-thirds of the production cost of ethanol was due to the

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Table 111.5.1 Bulk prices of selected chemicals, as of week ending 26 May 2000. Source: Chemical Market Reporter, 2000.

Product unit Price, $

Acetic acid lb 0.25

Acetone lb 0.165

1,4-Butanediol lb 1.16

n-Butanol lb 0.55

P-Carotene, 30% in oil kg 192.00

Citric acid, anhydrous lb 1 .oo D - Gluco s e, anhydrous lb 1 .oo

Glutamic acid, 99.5% kg 5.95

Ethanol, fuel grade gal 1.05

Lactic acid, technical, 88% Ib 0.72

Lactose lb 0.22

Mallic acid lb 0.81

Methanol gal 0.47

Methyl ethyl ketone lb 0.46

Succinic acid. anhvdrous lb 2.72

cost of corn (Cooper et al., 1999). The price of corn has in the past exceeded the price of ethanol, and the process was viable only because of the production of animal feed co- products (Ingram and Doran, 1995). Gallagher and Johnson (2000) estimated that the cost of ethanol production from cellulose sources, excluding the cost of the feedstock, is $0.42/gallon; if the cost of an agricultural residue raw material is included, the total production cost would amount to $0.58/gallon. Considering the current price of ethanol ($1.05/gallon, Table 111.5. l), there appears to be considerable economic potential for ethanol production from cellulose- and carbohydrate-rich food processing residuals. Furthermore, the quantity of lignocellulosic waste in the U.S. is substantial, and can potentialiy supply 10 billion gallons (more than six times the current national capacity) of ethanol for fuel use (Ingram and Doran, 1995). As noted above, the economic viability of producing a wide range of chemicals would to some extent be affected by petroleum prices, and fuel ethanol probably is not an exception to this. However, it should be pointed out that while agricultural commodities, including corn, can fluctuate significantly in price from year to year, these resources are renewable. Petroleum, on the other hand, is a limited, non- renewable resource, and although its price has been kept artificially low it will ultimately be subject to the laws of supply and demand and its price will inevitably increase as reserves are depleted.

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Table 111.5.2 Bulk Prices of Products Derived From Food Processing Residuals, or Competing with Such Products.

Product unit Price, $

Compost" lb 0.03

Meat mealb lb 0.14

Poultry feather mealb lb 0.18

Rendered poultry fat' lb 0.08

Soybean meald lb 0.08

Fishmeald lb 0.18 a Source: U.S. Census Bureau, 1999b.

Source: U.S. Census Bureau, 1999a, e. Source: DeRosa, 2000.

b

' Source: International Monetary Fund, 2000.

Table 111.5.3 lists shipments of selected products which currently or potentially can be manufactured from food processing residuals, as reported by the U.S. Bureau of Census (1999a, b, c, d, e, f, g, h). Among these, ethanol represents a fairly large market, with $2.26 billion of product shipped in 1997, more than half of that in the form of fuel-grade ethanol (U.S. Bureau of Census, 1999a). It should be pointed out that the market for ethanol may be expected to grow, due to increasing pressures to shift to renewable fuel sources after recent realignments in the global petroleum market and due to reasons discussed further below. The market for rendered products, on the other hand, amounts to $3.84 billion annually. Furthermore, the market for specialty chemicals is expected to grow steadily over the next few years (Reilly, 1999), and Table 111.5.4 lists the size and projected growth of selected segments of the specialty chemicals market in which chemicals recovered from food residuals would potentially compete. Competition within the specialty chemicals market as a whole is intense, however, and currently serves to limit prices (Reilly, 2000). In addition, although the overall market may be good, market conditions with respect to specific products may be different. Nevertheless, it appears that chemical production is an area of future growth, and that there would be room for future expansion for companies that enter this market. Taking a broad perspective, the total U.S. market for organic chemicals is about 100 million tons annually, of which only about 10% is manufactured through biobased processes. The remaining 90 million tons of organic chemicals currently derived from fossil fuels could potentially be replaced by renewable resources (National Research Council Committee on Biobased Industrial Products, 2000). Initially, biobased products would compete primarily in the area of oxygenated chemicals and materials, while petroleum would remain a competitive feedstock for liquid fuels and aromatic and alkane chemicals. Over time, adoption of biofuels and biobased aromatics and alkanes could grow significantly given investment in the necessary research and development.

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Table 111.5.3 Shipments of Selected Products, Nationwide and in Georgia. Source: US. Bureau of Census, 1999a, by cy d, e, f, g, h.

Product US . Shipments Georgia Shipments

Quantity Value ($1,000) Value ($1,000)

Agricultural and commercial pesticides 9,233,007 355,803 and chemicals

Biological preparations, including 7.4 million lb 98,988

Dog and cat food 8,261,844

Other Animal foods 17,776,726 1,090,055

bacterial pesticides

Ethyl alcohol 2,263,852

Fuel-grade ethanol 1,577,649

Fertilizer, &g only 2,913,311

Compost 842,500 tons 49,881

Synthetic organic medicinal chemicals, 9,030,635 in bulk, including antibiotics

Rendering or meat byproducts 3,838,961

Rendering and meat byproduct processing

1,209,029 25,941

Animal and marine feed and 2,406,031 67,089 fertilizer byproducts

Urethane and other foam products 6,196,664 other than polystyrene

Packaging polyurethane foam products

356,025 9,643

Furniture and furnishings 2,224,120 23,660 polyurethane foam products

Methanogenic digestion is one of the oldest and most established biochemical processes for waste recovery. Considerable heating value can be recovered in the methane produced by the process. More importantly, that energy can be released at a high temperature, making the methane a suitable fuel for power or steam generation. However, anaerobic digestion has not been widely adopted as a waste treatment process, due perhaps to some operational limitations and issues, both real and perceived. Anaerobic digestion is suitable mainly for high-strength waste, and wastewater treated anaerobically typically requires additional polishing prior to final discharge. The process is commonly perceived to be inherently unstable, but reliable operation can actually be achieved provided sufficient attention is devoted to the process. Odor problems can also arise from digester operation due to the production of hydrogen sulfide, but this can be avoided by the addition of ferric chloride to precipitate the sulfides. In any case, even when anaerobic digestion is used as a

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Table 111.5.4 Size and Projected Annual Growth of Selected Market Segments of the Specialty Chemicals Industry. Source: Reilly, 1999.

~~ ~~

Product Market Size in 1999 Projected Annual Growth $ 1,000,000 YO

Bulk chemical medicinals 11,573 4.0

Pesticides 7,973 1.3

Specialty polymers 6,392 5.7

Specialty surfactants 4,626 2.5

Food additives 4,319 3.6

Flavors and fragrances 3,896 5.5

Plastics additives 2,311 4.1

Biocides 1,124 2.6

treatment process, the biogas is commonly flared without energy recovery, as the current costs of electrical power and natural gas provide little economic incentive for it beneficial utilization. As pointed out above, these economic conditions result from a system that supports low petroleum prices, a practice that might be impossible to sustain given the non- renewable nature of fossil fuel resources. For this reason, it may be desirable to provide some incentive for industrial processing plants that generate biogas in the course of waste treatment to utilize the gas for power or heat generation, so that the capability to do so would be in place when future developments in the petroleum market make biogas utilization an attractive option.

Composting of food waste is a well-developed technology and is practiced at a number of locations, nevertheless opportunities for food waste composting in urban areas are typically limited work and Bogardus, 1991). Many communities have initiated yard waste composting programs, and these could possibly be expanded to include food waste as well, although there are some regulatory barriers to doing so, discussed below. A problem with compost production is the marketing of the product. For example, the City of Brunswick composts its biosolids, using yard waste as a bulking agent, and basically is unable to sell its product even at an extremely low price (Rhodes, 1999). This problem could possibly be avoided if the compost were produced, for example, by an integrated fruit or vegetable processing operation that had its own production farms. Such an arrangement would also enable the composting operation to undergo a streamlined permitting process, i.e., Permit-by-Rule, discussed below. Unless a market for the compost is secured, excess compost would have to be disposed of in a manner approved by the Georgia Department of Natural Resources (1997).

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111.5.2. LOGISTICAL ISSUES

The establishment of operations for the recovery of food processing residuals would require the consideration of the cost of transporting of these materials to the processing location. Because the materials would typically be higher in volume and lower in value per unit volume compared to the product, and perishable in nature, then the location of the processing operation should be driven by the location of the source of the materials rather than by the location of the markets. The perishable nature of the material raises additional issues on storage and vermin control. If on-site storage is required prior to waste collection or processing, then storage facilities that prevent these problems are required.

While institutional food waste from restaurants appears to be substantial, close to 280,000 tons/year in Georgia, it is generated by a very large number of establishments which would typically rely on municipal services for the disposal of their waste. Institution of a program for the segregation of food waste at the generation point, and the collection of the waste for recovery and processing, would be a considerable challenge. Possibly this can be facilitated through the Georgia Hospitality Environmental Partnership, of which the Georgia Department of Community Affairs is currently a member, and which aims to provide technical support in developing recycling systems for hotels and restaurants, provide education and training for hotel employees, and conduct seminars and workshops for hotel management groups. Nevertheless, it may be more feasible instead to work with a large institution, perhaps with an established waste segregation, collection, and recovery infrastructure, to undertake pilot and demonstration studies for institutional food waste recovery technologies. Such a strategy would help mitigate the cost of, collecting, transporting and storing the waste. For example, the Georgia Department of Corrections currently operates six composting sites and dverts 8,564 tons of waste from landfills (Georgia Department of Community Affairs, 1998). To initiate pilot or demonstration projects on foodservice waste utilization, cooperative arrangements between university researchers and the Department of Corrections could be established to divert a fraction of the food waste to alternative recovery processes. An additional advantage of this approach would be that the Department of Corrections would already have equipment in place to perform preprocessing of the waste, e.g., grinding and mixing, and the preprocessed waste could be fed directly to a downstream process. This approach could also increase the effective waste recovery capacity of the Department of Corrections, and, at least for the life of the project, increase the amount of waste diverted from landfill. Alternatively, a large research university could establish an institutional food waste recovery pilot or demonstration at a campus location, using material from its own foodservice operations. This approach may be logistically simpler and more efficient for the researchers, allowing closer monitoring and control of the project. An additional advantage would be with respect to technology transfer, as the site would be readily available for tours and training of potential end-users of the technology, and a staff that is focused on research, education, and training would be on hand. However, this approach would require more new equipment if preprocessing of the waste is required, although that equipment would presumably be used beyond the life of the project for future research activities. It may also entail higher personnel costs, for staff to undertake the waste collection and preprocessing operations.

Transportation would also be an issue with respect to industrial food processing Because the waste materials are of relatively low value and high in moisture residuals.

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content, hauling costs would be high, although these would be offset if the waste is used to manufacture a product with high value and/or with a high yield from the waste. An alternative approach would be to perform some intermediate processing of the waste to reduce the cost of hauling it, for example moisture reduction through physical means. This is actually being practiced at this time by a vegetable processing plant in the Atlanta region, although their waste material is still mostly landfilled. Using a mechanical expeller, the vegetable processor realized a substantial savings in their disposal cost by reducing the moisture content of the vegetable trimmings from >90°/o down to 35-4Oo/o. Such an approach may not always be feasible, however, for a number of reasons. There is an energy cost associated with the moisture and/or volume reduction, and this will have to be balanced against the savings in transportation costs. The expelled moisture becomes a wastewater, and in some plants this may have important cost implications, but the wastewater could possibly be utilized, particularly if it can be concentrated using membrane or other technology. Nevertheless, this experience underscores the feasibility of using some preprocessing techniques that would reduce waste volume and/or mass while retaining the desirable qualities of the material, to reduce potential transport costs. Potential technologies for this purpose include mechanical or thermal drying for solid materials, and membrane filtration and flash evaporation for liquid wastes.

111.5.3. ENVIRONMENTAL AND PUBLIC HEALTH ISSUES

Rendering operations serve an important function as they provide an outlet for a substantial quantity noxious, readily putrescible material that might otherwise go unused and pose a public health hazard and nuisance. Rendering plants, however, inevitably generate some undesirable odors, and may be perceived as undesirable neighbors by the communities in which they are located. Securing this market for food processing by-products would therefore require research into odor control and minimization techniques in the rendering industry.

Georgia law completely prohibits the feeding of institutional food waste to swine, even if it is cooked or otherwise processed prior to use. This regulation was enacted because past disease outbreaks have occurred as a result of feeding improperly cooked food waste. A number of other states allow this practice, though and some require waste feeders to be licensed and to cook the waste prior to use. The regulation mainly targets meat products as the source of pathogens, hence certain industrial residuals, e.g. bakery products, grain processing wastes, fruit and vegetable waste, can be used directly as feed because they are not considered to harbor potential animal pathogens. In addition, the law is specifically directed to swine feeding, because the similarity between the human and porcine gastro- intestinal systems creates a high probability for the transmission of gastro-intestinal pathogens between these species. By the same token, however, human food waste would be more efficiently utilized, and would probably require less augmentation with other feed ingrelents, by hogs compared to other animals.

Composting operations that utilize food waste are less tightly regulated in comparison to those that utilize municipal wastewater biosolids. The U.S. Environmental Protection Agency’s Part 503 rule stringently regulates the composting methods and pathogen limits for biosolids composts that can be publicly distributed. However, in the solid waste management rules of the Georgia Department of Natural Resources (1 997), only

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composting operations that exclusively use yard trimmings are specifically exempted from regulation as solid waste handling facilities. Consequently, in this state, food waste composting operations are potentially subject to the same regulation as biosolids composting operations, and this may be a reasonable policy due to the potential of food waste to carry pathogens and to attract vermin. However, these facilities can avail of a streamlined permitting process, referred to as Permit-by-Rule, provided 75% of the material composted is generated by the owner of the composting operation. The reasoning for this exception is not clear, however, as the

A potential use of oily food waste, after suitable processing, is as fuel or a fuel component in diesel engines. The material is generally considered unsuitable for conventional automobile (Otto cycle) engines because these use a fuel that is volatilized prior to entering the combustion chamber. The use of the recovered oil as a substitute for diesel fuel would be consistent with resource conservation goals, since it displaces a fossil fuel. However, diesel engines generate small particulate matter, which is linked to respiratory health problems, in quantities larger than other internal combustion engines. For this reason the federal government is taking steps to reduce the potential public health impact of diesel emissions, including the institution of more stringent limits on the allowable sulfur content of the fuel. The initiative is in its early stages, however, and its future implementation is as yet uncertain. An addition consideration is that the Atlanta metropolitan region is currently in substantial non-compliance with respect to air quality, and additional diesel emissions could exacerbate this problem. The recovered oil or the fuel substitutes manufactured from it may consequently have to be shipped out of state, or to a region of the state where the emissions would not cause unacceptable degradation of air quality.

Another air quality issue related to mobile sources has to do with the use of oxygenates in gasoline formulations. Oxygenates are added to gasoline in order to reduce the emission of carbon monoxide and hydrocarbons due to incomplete combustion. The chemicals most commonly used for this purpose are methy tert-butyl ether (MTBE) and ethanol. However, due to its high water solubility and recalcitrance to biodegradation, MTBE has become a major water contaminant. Consequently, the U.S. Environmental Protection Agency has recently announced plans to eliminate or limit the use of MTBE in favor of more environmentally benign oxygenates. Hence the demand for ethanol as oxygenate for gasoline should increase, and this may enhance its market value. The use of ethanol or mixed alcohols as fuel (rather than as fuel additive) in internal combustion engines is possible, and even though there is already available on the market a versatile fuel vehicle that can use up to 85% ethanol in gasoline as fuel (Tullo, 1998), the practice has not gained wide acceptance in this country. The ethanol and mixed alcohol fuels market may prove to be a strategic one, however, if environmental and resource conservation issues force the widespread use of alcohol fuels.

111.5.4. REGULATORY ISSUES

Almost universally, the need to comply with environmental regulations is the principal factor driving manufacturers to undertake waste treatment, reduction, and recovery. A regulatory approach which encourages the examination and implementation of wasFe reduction and recovery alternatives in preference to treatment could increase the implementation of such programs in the state. For example, some companies have recently

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been required to develop and submit pollution prevention plans prior to having their consent orders lifted. The company in effect makes a binding commitment, subject to monitoring by environmental regulators, to reduce waste generation within the plant. This approach could be standardized in order to broaden industrial participation in pollution prevention and waste reduction.

While water use reduction would be expected to provide sigmficant benefits among Georgia food processors and to the communities wherein they are located, implementation of a water conservation program may pose problems to some companies. However, unless commensurate reductions in the organic material carried by the wastewater are achieved, reducing the volume of the wastewater would result in increasing its concentration. Unfortunately, some jurisdictions regulate industrial wastewater generators on the basis of concentration rather than on the total mass of pollutant discharged. Ideally, reductions in water use and organic material would indeed be achieved simultaneously, however the operation may find it more practical to implement changes in a phased manner, or it may simply be impracticable to further reduce the mass of organic material. It is ironic that implementing a water conservation program as a waste reduction measure could cause a food processor to run afoul of environmental regulators. However, this is exactly what would happen unless the regulators concerned consider total pollutant load rather than relying solely on pollutant concentration. Furthermore, it does not seem fair that a processing plant discharging a small quantity of wastewater at high concentration would be penalized, while a large operation generating a high volume of wastewater at low concentration, but effectively discharging an equal or higher mass of pollutant, would not. On the other hand, concentration limits may be necessary in some cases to adequately safeguard the municipal wastewater treatment system. Nevertheless, it seems that a re- examination of concentration-based industrial effluent regulations is called for in light of potential water conservation opportunities. A related concern is that the necessarily fragmented administration of municipal water supply and wastewater treatment services makes the institution of broad incentives for industrial water conservation and wastewater reduction difficult, as each jurisdiction would have to consider its unique circumstances and facilities. Such incentives would be desirable, however, given the potential impact of these waste reduction programs.

A second regulatory issue related to water conservation has to do with food safety. Since the institution of the Hazard Analysis and Critical Control Points (HACCP) system, the frequency of washing and disinfection in the production process has increased substantially, driving up water consumption across the food processing industries, and particularly in poultry processing. Merka (1998) observed that prior to the institution of HACCP, a number of poultry processors had gotten their water use down to 5-6 gal/bird, but that rose to nearly 10 gal/bird after HACCP was put in place. While food safety is a high priority, it can reasonably be achieved while maintaining a stable rate of water consumption through the development of appropriate management strategies. Merka (1 998) considers the high water use an early response to HACCP as the processors become more familiar with the regulation and the process changes that would be required to achieve, and believes that after this adjustment period water use can once again be reduced to their former levels.

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111.6. STRATEGIES TO ENHANCE REDUCTION AND RECOVERY OF FOOD PROCESSING RESIDUALS AND INSTITUTIONAL FOOD WASTE

Opportunities for the reduction and recovery of food processing residuals and institutional food waste are plentiful. The task is not to simply identify potential opportunities, but to focus on those that are technologically mature, or at least approaching that stage, and that can potentially effect substantial reductions in waste disposal volume and costs and accrue in economic benefits for the citizens of the state. Rather than focusing on specific potential products, technologies and sectors critical to the development food waste recovery processes are identified, and potential strategies to support the development and commercialization of these processes are discussed.

Food processing residuals generated by the meat, poultry and seafood, bakery, and grain processing industries are substantially absorbed by the existing industrial infrastructure and converted into animal feed products, but collectively represent the largest waste volume in the food processing industry. Residuals generated by fruit and vegetable processing and by nut and oilseed processing, on the other hand, are substantially unused or underutilized. Waste from commercial and other foodservice operations, with the exception of a major composting enterprise operated by the Georgia Department of Corrections, is for the most part disposed of through municipal waste disposal systems. Potential strategies and initiatives for the reduction and recovery of these different residual materials will be considered. A number of initiatives are grouped together as a broad or overarching strategy, intended to impact a specific area or direction that affects food waste reduction and recovery. The remaining initiatives are grouped by type of activity, i.e., education/ technology transfer, research, and policy.

111.6.1. WATER CONSERVATION

Water conservation should be aggressively pursued given that a substantial quantity of wastewater, estimated at 18.8 billion gallons/year, is generated. This wastewater is estimated to carry 208,600 tons of organic material (as BOD), hence the treatment of this wastewater in publicly owned treatment works (POrWs) results in the generation of another problematic residual, municipal biosolids. Furthermore, municipal water supplies generally undergo a series of treatment operations, including coagulation, sedimentation, filtration, and disinfection, operations which consume chemicals, energy, and manpower, and generate solid residuals. Therefore, if significant reductions in industrial water usage can successfully be realized, the potential impact is significant. In order to promote and achieve water conservation in the food processing industry, the following strategies should be pursued:

Educational and outreach programs intended to train production and maintenance personnel and superintendents should be widely offered to industrial clients. These programs should be designed to provide as much practical, hands-on information as possible. These programs should be scheduled and located such that they would be accessible to plant personnel, and given typically tight productions schedules this will often mean that the

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programs will need to be held at the plant site, and that the training materials and equipment be sufficiently portable to permit this. These programs should also be delivered in a medium that permits free communication between the trainer and the target audience, and given the demographics of industry production workers this may require fluency in a language other than English.

Training on techniques to limit the quantity of organic material carried by the wastewater, such as dry cleaning, spill control, microscreening, and membrane filtration, should be offered and conducted as well.

0 Research aimed at developing sanitation and food safety practices consistent with HACCP objectives but entailing minimal water usage should be undertaken. This may include the development of alternative disinfection methods and the use of advanced techniques for detecting microbial contamination.

Research and demonstration projects on industrial water reuse should be undertaken. The demonstration phase is critical for this activity to show that food safety goals can be achieved even with water reuse provided that the appropriate technology is used and is implemented in the proper manner.

Research on the development of processing alternatives that minimize water usage should be undertaken. Examples include the use of steam rather than aqueous solutions for peeling operations and of air jets rather than water baths for initial cleaning in fruit and vegetable processing.

A critical review of effluent regulations instituted by different local jurisdictions should be undertaken. Because water use reduction may result in increased effluent concentration, plants that undertake water conservation programs could potentially be penalized for their success if effluent regulations are based on concentration limits. Mass-based limits, on the other hand, would permit an operation to reduce the quantity of its wastewater while continuing to discharge the same amount of organic material. Hence, mass-based effluent limits appear more conducive to industrial water conservation, however concentration-based limits may be necessary to ensure reliable treatment plant performance. The development of effluent regulations that would address both of these objectives would require a comprehensive review of the wastewater load, the treatment capacity, and the effluent requirements of the POTW. Such an exercise should be encouraged by the state regulatory agencies, with technical assistance to be provided by the state body or by the GEP technical partners, if needed. Such a review might also be conducted in conjunction with a review of the billing structure for industrial water users, which can also be tailored to promote water conservation.

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111.6.2. ESTABLISHMENT OF BIOREFINERIES FOR PROCESSING TRADITIONAL AGRICULTURAL PRODUCTS

While the continuing depletion of non-renewable resources provides substantial impetus towards a biobased products manufacturing infrastructure, much of the infrastructure and technology required to achieve such a shift are not currently in place. Even in the case of ethanol production, which is a relatively mature industrial fermentation process, technologies for the production of ethanol from lignocellulosic waste via hydrolysis and fermentation have aroused little commercial interest. A novel technology for simultaneous saccharification and fermentation of 5- and 6-carbon sugars is in the early stages of a demonstration process, and could take several years to validate (National Research Council Committee on Biobased Industrial Products, 2000). Particularly with respect to by-product utilization, a collection infrastructure exists only for those residuals with established products and markets, and even then small-scale generators are rarely served by it. Consequently, the large-scale utilization of Georgia's food processing residuals and institutional food waste in industrial-scale by-product recovery operations would require both technological and infrastructure development.

A possible approach is described by the biorefinery concept (National Research Council Committee on Biobased Industrial Products, 2000). Like a petroleum refinery, a biorefinery would be a processing facility which utilizes one or a limited number of feedstocks to manufacture a range of products. A potential biorefinery facility could be based on a wet corn milling plant, which could potentially produce corn starch, corn syrup, dextrose, dextrins, organic acids and biochemicals, ethanol, and feed ingredients. Some lessons from the operation of petroleum refineries, which would also be applicable to biorefineries, include:

Refineries produce more and more products from the same feedstock over time, thereby diversifjmg outputs.

Refineries are flexible and can shift outputs in response to change.

0 Processes in refineries improve incrementally over time.

Process improvement invariably makes the cost of raw material the dominant factor in overall system economics.

With respect to waste reduction and recovery, a biorefinery operation would have a substantial incentive to develop alternative products and processes for by-product and waste utilization. Furthermore, a biorefinery would be well organized to pursue such possibilities, especially with respect to ensuring that by-product and residuals are of a quality suitable for recovery as other value-added products. Consequently, the development of biorefineries to undertake food processing activities would lead to the reduction of food processing residuals. For example, biorefineries could be established around two of the state's major crops, soybeans and peanuts. The possibility of soybean-based biorefineries producing oil, protein isolates, food products and supplements, and feed has been suggested (National Research Council Committee on Biobased Industrial Products, 2000), and the possibility of ultimately converting the hulls into chemical products would make such a venture more

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attractive. A similar biorefinery could conceivably be structured around peanut processing as well, although the current product range for soybeans appears broader, more diverse, and more versatile compared to peanuts. At the same time, nuts and oilseed hulls, estimated at 358,800 tons/year, are a major food processing residual, and are utilized primarily for composting, for animal bedding, and to provide roughage in feeds, although a limited quantity of pecan hulls is ground for use as filler in plastic production. Whether it would be more beneficial to a biorefinery to process the shelled nuts or seed, or shell the raw material on-site and use the shells to manufacture additional products would depend to a great extent on the products that could be derived from the shells. Regardless of whether or not shelling is integrated into the refinery operation, however, the lignocellulose represents a potential resource, and initial research efforts would focus on the conversion of the lignocellulosic material into fermentation feedstocks and chemical commodities, with more specialized chemical products targeted for longer-term development. The establishment of biorefineries based on soybean and peanut processing would also be consistent with the rural development goals enunciated by the state.

The biorefinery concept appears to hold up well for products such as corn, soybeans, and peanuts, which are rather versatile and from which a wide range of products can be manufactured through established technologies. Whether such an approach would be viable for another the state's major agricultural products, poultry, is another matter. In theory a wide array of products could be manufactured in an industrial complex having a poultry slaughter and dressing operation as its front end, including food additives, protein isolates, oil, biofuels, feed ingredients, and insulation. Additional development of many of these technologies is required, however, before such a facility can be realized. Furthermore, the establishment of biorefineries around poultry processing plants would challenge current industry practice of shipping residuals off-site for rendering into animal feed. The refinery could nevertheless be a useful model, due to the economic benefits of having multiple, tightly integrated, symbiotic operations at a single site.

In order to promote the establishment of biorefineries as a vehicle for rural development and more efficient resource utilization, the following initiatives should be undertaken:

A committee should be appointed by the state to evaluate the feasibility of and develop an implementing plan for the establishment of biorefineries based on major agricultural products of the state. This could initially be limited to those products for which a wide range of processing options are currently available, i.e. peanut and soybean, and to those produced in an extremely large volume, i.e. poultry. The committee would identify potential research and technology requirements, financial requirements, candidate sites, and potential industry partners, among other things. Note that a committee constituted to evaluate the biorefinery concept would not be restricted to food crops, and would probably evaluate non-food crops (e.g., cotton) as well.

Research that would expand the range of potential products from the candidate biorefinery crops should be undertaken. Examples of such research include the hydrolysis of nut hulls into fermentable carbohydrates,

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and enhanced oil recovery from poultry processing and subsequent biofuel production.

111.6.3. PHASED DEVELOPMENT OF FOOD WASTE UTILIZATION AND RECOVERY TECHNOLOGIES AND INDUSTRIES

Regardless of whether the biorefinery concept is pursued, a strategy that would initially focus on established products, technologies, and infrastructure, while investing in the development and expansion of these for an eventual shift into more novel, higher-valued products, appears to be the most reasonable approach for enhancing waste recovery in the food processing and institutional food sectors. This does not necessarily mean that markets currently served by the residuals will be abandoned, but that alternative higher-value markets will be sought and developed to enhance by-product recovery and to reduce potential constraints imposed by waste and by-product management requirements on future industry growth.

Current products from different food-based residuals are listed in Table 111.6.1 , along with intermediate- and long-term product goals for these residuals. Among the food processing industries, the first four industry groups listed (meat, poultry and seafood processing; bakery operations and grain processing; fruit and vegetable processing; and nut and oilseed processing) produce the largest quantities of residuals and would probably deserve the greatest amount of attention and resources with respect to waste reduction efforts.

For meat, seafood, and poultry processing, the current residual collection and processing infrastructure appears effective in capturing substantially all of the waste material and converting it into animal feed. In addition, research on the conversion these residuals into alternative, higher-value products has not been pursued as aggressively as research on the conversion of lignocellulosic wastes, except possibly in the area of enzymatic conversion, i.e., lactic acid fermentation into animal feed ingredients. Consequently, the lead-time required for the development of new products from these materials is probably longer compared to other residuals, and the maintenance of the current residual recovery products and infrastructure would constitute the main intermediate-term objective.

Like meat, poultry, and seafood processing residuals, residuals from the bakery and grain processing industries are typically recovered as animal feed, with waste doughs even undergoing a rendering process to produce a dry feed ingredient. In contrast to those proteinaceous wastes, however, bakery and grain processing residuals contain a large amount of or are readlly converted enzymatically into reducing sugars that can serve as feedstock for industrial fermentation processes. Since this material is primarily starch rather than cellulose or lignin, the hydrolysis process is much better established. Also, this material is solid or semisolid and could serve as a good substrate for solid-state fermentation processes. Potential intermedate-term technologies are the production of chemicals and SCP- or lactic acid-enhanced feeds through solid substrate fermentation, and of fermentation feedstocks and/or chemicals through hydrolysis and/or fermentation.

Fruit and vegetable processing residuals would be mainly cellulosic in nature, and although hydrolysis of this type of material is possible it has not been commercially applied

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Table 111.6.1 Current and Potential Products from Different Food Processing Residuals.

Future Products Industry/Activity Residual(s) Current Products/ -

Disposal Methods Intermediate Long- term

Meat, poultry and seafood processing

Bakery operations and grain processing

Fruit and vegetable processing

Nut and oilseed processing

Dairy products

Beverage Droducts

Offal, blood, feathers, DAF sludge

Waste doughs, breads, bakery hgredients, waste grain, spent brewer's/ distillers' grain/ yeast

Trimmings, culls, fruit pomace

Hulls, meals

Waste beverage

Animal feed

Animal feed

Landfill, land application, animal feed

Compost, animal feed, plastic filler

Food and feed in limited quantities

Municipal sewer

Animal feed, includulg lactic acid fermentation

Feed ingredtents, via SCP production or lactic acid fermentation

Fermentation feedstocks

Commodity chemicals

Feed ingredients, via SCP production or lactic acid fermenta tion

Methane / biogas

Fermentation feedstocks

Biofuel(s) Commodity chemicals

Commodity and specialty chemicals

Biofuels

Protein isolates Animal fats,

biofuels Insulation material

Specialty chemicals

Biofuel(s) Commodtty and

specialty chemicals

Specialty chemicals

Specialty chemicals

Specialty chemicals

to a great extent. Although potentially usable as animal feed, their high moisture content and low nutrient content makes the delivered cost of these residuals prohibitive. It may be possible to enhance the feed value of these materials through SCP production or lactic acid fermentation, but this may be difficult, particularly with vegetable trimmings, due to the limited concentration of fermentable material, unless supplemental substrate is provided, preferably in the form of a waste material with a complementary nutrient profile. An alternate course is to use anaerobic digestion to produce biogas, while the possibility of more desirable products through cellulose hydrolysis and fermentation is explored.

Whey produced by the dairy industry is used in both food and feed production, but in limited quantities only. As noted earlier, the supply of whey far exceeds the demand for products derived from it, and there are no new technological developments that promise to change this situation (Council for Agricultural Science and Technology, 1995). Nevertheless, the range of potential products from whey is large (Table III.4.6), and provided the necessary markets can be developed the recovery of this residual should become a viable activity.

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Residuals from the production of grain-based fermented beverages are generally utilized for food (brewer's yeast) and feed production, while the grape pomace generated by Georgia's small winemaking industry is returned to the vineyards to fertilize the next crop. Chemicals are potentially recoverable from the grape pomace via biological or chemical means, but the quantity of this residual is small. Waste beverage from soft drinks packaging operations, given its sugar content, is potentially usable as fermentation medium, perhaps requiring no more than pH adjustment prior to inoculation, and is a potential raw material for biofuels and chemicals.

111.6.4. RECOVERY OF INSTITUTIONAL FOOD WASTES

Institutional food wastes are currently disposed of mostly through municipal solid waste management systems, i.e., by landfilling. One exception is the Georgia Department of Corrections food waste-composting program, which diverts more than 8,500 tons/year of waste from landfills. However, this is only a small fraction of the total amount of institutional food waste generated in Georgia, estimated at 474,000 tons per year. Of that amount, an estimated 422,000 tons (SSO/o) is generated by commercial establishments, of which restaurants produce the bulk. Consequently, institutional food wastes represent a large pool of material, and their reduction or recovery could potentially have a substantial impact on the quantity of food-based residuals disposed of in landfills. Other than composting, two possible means to recover the value in institutional food wastes are animal feed production and anaerobic digestion. Feed products obtained through the processing of institutional food wastes would be specifically prohibited from inclusion in swine rations, to avoid public and animal health problems, and standards on pathogen destruction, nutrient content and stability would have to be established and maintained. Nevertheless, and despite existing Georgia law, animal feed seems to be a product towards which institutional food wastes could readily be diverted. Anaerobic digestion is another alternative, although biogas is not considered a very desirable product. Over the longer term, the evaluation and development of the food waste as a feedstock in solid or liquid fermentation could be examined. The nutritional profile of the material may permit microbial cultivation with minimal micronutrient augmentation, enhancing the economics of its utilization. On the other hand, sterilization requirements for the waste may be more stringent compared to alternative raw materials. Another issue may be the potential variability in the composition of the waste. Particularly if the fermentation process places stringent requirements on medium composition, it may be necessary to limit the types of waste accepted, to frequently test the medium, to have alternative substrates for blending, or even to avoid use of the waste altogether. Solid substrate fermentations, however, are more flexible in this respect than traditional liquid phase fermentation processes, and could consequently be preferable.

Application of a system for institutional food wastes recovery could be substantially constrained by the logistics of waste collection, considering that the bulk of the waste is generated by a large number of relatively small establishments that currently do not consider the disposal of their waste a problematic issue. However, when the feeding of these residuals to swine was permitted, these issues were apparently dealt with successfully by the swine farmers who collected and used the waste, so it is clear that these issues can be overcome at some scale. It may be possible to avoid these logistics issues during the technology development and demonstration phase by a undertaking a cooperative project with a large institutional food waste generator, possibly one with an established collection

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and/or recovery system. Wider-scale implementation of an institutional food waste recovery process, however, would require that these issues eventually be addressed and surmounted.

With these concerns in view, the following initiatives are recommended to promote increased recovery of institutional food wastes:

0 Review current regulations on the use of institutional food wastes for animal feeding, with the end in view of developing a policy structure that maximizes the beneficial reuse of institutional food waste for animal feedlng purposes while safeguardmg animal and human health.

0 Assess the logistical issues related to the collection of institutional food wastes, particularly in situations where the waste is produced mostly by multiple small generators (e.g. restaurants) and develop management strategies and state-supported incentives that would permit potential processors to undertake this activity more economically.

0 Research on the processing of institutional food waste into animal feed ingredients should be undertaken. The research would establish the processing methods and techniques required to eliminate or minimize the public and animal health risks associated with feeding institutional food waste to livestock.

0 Research on the incorporation of processed institutional food waste into swine, dairy, beef cattle, broiler, and layer operations should be conducted. The research would also establish the levels at which the processed institutional food waste could be incorporated into feed rations while meeting the nutritional requirements of the animals and obtaining

Research on the use of institutional food for fermentation process feedstock should be conducted. The research would assess the preprocessing operations, e.g. grinding, homogenization, sterilization, nutrient supplementation, etc., required before the waste can be used for fermentation. The research will also investigate specific products for which the institutional food waste may be a particularly suitable raw material.

111.6.5. EDUCATION AND TECHNOLOGY TRANSFER INITIATIVES

The need for more information on waste reduction and recovery programs and opportunities was identified earlier, hence education and technology transfer is an important component towards achieving pollution prevention goals. Specific initiatives in this area include:

Technical assistance activities of the GEP partners should be continued and strengthened. Although it appears that relatively few companies are aware of them, these services are generally received quite positively. However, efforts

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should be made to more broadly promote GEP services to industry. The services provided by the GEP partners include:

o Technical assistance through site assessments for waste reduction and recovery. Personnel from GEP partner organizations assist plant personnel in identifying and exploring waste reduction opportunities, and assist in the implementation of any waste reduction measures adopted.

o Technical assistance in environmental and regulatory compliance. As noted earlier, the need to comply with environmental regulations is the common driving force behind waste reduction and treatment efforts. Personnel from GEP partner organizations have many times been called in initially to assist on environmental compliance issues, and any help provided in this area has in our experience always been greatly valued and appreciated and very well-received by industry. Such contacts provide the opportunity to have the client examine waste reduction measures as a means of achieving environmental compliance as well as cost reduction, and as an alternative to more conventional waste treatment or disposal methods. Technical assistance in the area of environmental compliance has proven a particularly effective means of introducing clients to potential waste reduction opportunities in their processing operations. Linkages between the GEP partnership, the Georgia Department of Natural Resources Environmental Protection Division, and local regulatory bodies should be cultivated to identify potential client companies that could benefit from waste reduction and recovery. This should not confict with the non-regulatory role of the Pollution Prevention Assistance Division, since its services are restricted to technical assistance and technology transfer and it has no role in assessing environmental compliance. This assistance may involve helping clients to respond to a notice of violation from local or state environmental regulators, to identify waste reduction and recovery alternatives that may help achieve environmental compliance, and to decipher and comply with regulatory requirements and permit guidelines pertinent to their operation.

Training on the use of full-cost accounting as a decision support tool in the institution of waste reduction measures should be provided to industry and corporate personnel. Very often, the true cost of a waste material is not realized. For process losses, e.g. spills, typically the only cost considered is the price of the material itself. For processing residuals, on the other hand, the costs of treatment and/or disposal are the main cost components considered. To reflect the true cost of the waste, the inputs involved in acquiring, handling, and processing the material prior to its becoming a waste, and the cost collecting, handling, treatment, and disposal of the waste should all be considered. Full-cost accounting techniques would consider all cost factors, and enable managers and manufacturing personnel to justify the

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cost equipment and operational modifications adopted to achieve waste reduction.

Publish and circulate waste reduction guides targeted to institutional food waste generators. Such documents should contain simple, easily implemented measures for waste reduction explained in readily understandable language.

111.6.6. RESEARCH INITIATIVES

Research is required to validate the benefits and effectiveness of waste reduction and to develop technologies for resource recovery. Specific research needs include:

0 Field-based grading and cleaning of the produce could substantially reduce the quantity of residual material generated at the processing plant, and facilitate the return of these materials to the soil. This practice should be strongly encouraged since options for the recovery of fruit and vegetable waste appear limited. Demonstration activities that would validate the benefits of this practice should be conducted, along with research to developed improved mechanical harvesting equipment.

0 Research to improve and optimize the enzymatic hydrolysis of cellulosic and lignocellulosic substrates should be undertaken. Hydrolysis is a necessary step preliminary to fermentation for the production of ethanol, however improvements in conversion and yield of cellulosic and lignocellulosic substrates would probably need to be realized before commercial-scale application becomes attractive (National Research Council Committee on Biobased Industrial Products, 2000). Adoption and optimization of the hydrolysis process for different residual materials would therefore be a top research priority, and will be key to broadening the utilization of lignocellulosic material for industrial fermentation.

Research on the development of alternative products from meat, poultry, and seafood processing residuals should be undertaken. These products could include lactic acid-enhanced feeds, protein isolates, animal fats, biofuels, and insulation material.

0 Research on the bioconversion of wastes from bakery and grain processing should be performed. Enzymatic hydrolysis and liquid fermentation could be used to produce chemicals and fermentation feedstocks, while solid state fermentation could produce chemicals and SCP- or lactic acid-enhanced feeds.

Research on the bioconversion of fruit and vegetable trimmings should be undertaken. The feed value of these materials could be enhanced through solid state fermentation, or energy could be derived from them through anaerobic digestion.

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Research on the bioconversion of nut and oilseed hulls should be undertaken. Hydrolysis of these lignocellulosic materials would produce fermentation feedstocks, which could subsequently be converted into chemical commodities.

Research to quantify the benefits of composting and land application should be undertaken. The results of this research should be made available on a timely basis to the food processing industry, to institutional food waste generators, and to potential compost producers.

Research on odor control and minimization in the rendering industry should be undertaken, to secure this market for food processing by-products.

Research to examine alternatives and/or enhancements to the dissolved air flotation process commonly used for separation of protein and fat from poultry processing wastewater should be undertaken. Alternatives techniques and end products for processing the DAF sludge should also be investigated.

Research and demonstration on techniques that can be used for volume and mass reduction of food wastes prior to further processing and recovery should be conducted. Transport costs are expected to become a major factor affecting the profitability of resource recovery operations utilizing food wastes, and techniques that would reduce waste volume and mass while retaining the desirable properties of the waste material could substantially reduce these expenses.

111.6.7. POLICY INITIATIVES

Policies that would promote waste reduction and utilization should be formulated and implemented.

Policies regulating the composting of food processing and institutional food wastes should be reviewed. For example, Permit-by-Rule provisions in the state solid waste regulations (Georgia Department of Natural Resources, 1997) apply only to operations where 75% or more of the composted material is generated on-site, although it is not clear why composters that obtain more than 25% of their material off-site pose a higher risk. While the need to safeguard public health and environmental quality is recognized, the solid waste regulations do not in general encourage composting, and should be modified to promote resource recovery.

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