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Changing Paradigms: From Wastewater Treatment to Resource Recovery
Glen T. Daigger, Ph.D., P.E., BCEE, NAE
Senior Vice President and Chief Technology Officer
CH2M HILL
9191 South Jamaica Street
Englewood, CO 80112
303-771-0900
ABSTRACT
In spite of the availability of implementable technologies and approaches, adoption of energy
reduction and energy and nutrient recovery options by the used water profession has been slow.
This occurs for a number of reasons. Among them are the siloed nature of the educational and
regulatory systems, the professional organizations, and the relevant institutions. Codes and
standards also inhibit relevant changes. Economics have not historically encouraged greater
energy and nutrient recovery, but this factor is changing. Procedures for analyzing evolving and
innovative technologies and approaches compared to more conventional options often contain
biases against their adoption. Systematic barriers are also inherent in the innovation process,
including the time required by the technology learning curve and by the adoption process.
Understanding and addressing these barriers can lead to more rapid adoption of new, beneficial
technologies and approaches, creating significant societal benefits.
KEYWORDS
Energy, Nutrients, Recovery, Paradigms, Innovation, Adoption
INTRODUCTION
The municipal used water (also referred to as wastewater) stream contains a number of
constituents which can be extracted for useful purposes (Daigger, 2010, 2009, 2007). Water is
certainly one which is broadly addressed by the topic of water reclamation and reuse (Jimenez
and Asano, 2008). The used water stream also contains organic matter, nutrients, and heat which
can be extracted for a variety of purposes. Organic matter can be converted into biogas through
anaerobic processes, and the biogas can be recovered and used for energy (heat, electricity)
production through combined heat and power (CHP) systems. Microbial fuel cells can convert
the energy value of organic matter into electricity (Logan, et al., 2006). When concentrated
sufficiently, organic matter can be combusted and the heat energy recovered, for example again
for electricity production. Heat can be extracted directly from the used water stream and
upgraded for a variety of uses using heat pump technology. Nutrients can also be extracted.
While the specific technologies to accomplish energy and nutrient recovery are evolving,
practical technologies already exist and are applied in practice, although not in sufficient
magnitude relative to the existing potential.
Alternate approaches also exist which can facilitate greater recovery of energy and nutrients
from the municipal used water stream (Daigger, 2010, 2009, 2003). Source separation represents
one such approach where the relatively uncontaminated water (greywater), organic matter
(blackwater), and nutrients (yellowater) are separately collected. This separation can facilitate
the recovery of resources from the municipal used water stream. The application of
decentralized systems can also facilitate energy and nutrient recovery (Daigger and Crawford,
2007).
In spite of the availability of superior approaches to municipal used water management, their
potential application is often neglected during planning studies, or their potential advantages are
not reasonably assessed. As a result, the full potential of these approaches is not being delivered
to the public by the wastewater management profession (Guest, et al., 2009, 2010).
This paper addresses two topics. First, it provides a brief summary of available and developing
options to recover energy and nutrient from the municipal used water stream. Technologies and
management approaches will be briefly summarized, including a brief description of the
technology, its development status, and its potential contribution to increasing the sustainability
of municipal used water management systems.
Second, existing barriers to the more widespread application of these technologies by the used
water management profession will be addressed, along with approaches to address and reduce
these barriers (Daigger, 2010, 2009; Guest, et al., 2009, 2010). These barriers include factors
such as:
Lack of understanding of the available opportunities by practicing professionals, resulting
from the current structure of the educational system,
Regulatory barriers which resulted in “siloed” approaches to water, used water, and
resource management,
Institutional structures which reinforce the “silos” which restrain the implementation of
new approaches, and
Inappropriate methods of analysis which introduce biases against new approaches and
technologies.
These barriers will be addressed in the context of the existing, well developed, knowledge of the
adoption of innovations. These are factors which the profession can address, thereby allowing
more rapid implementation of alternate approaches which can contribute to greater overall urban
sustainability. The paper will not only identify these barriers but it will also present approaches
for overcoming them.
ENERGY AND NUTRIENT RECOVERY OPTIONS
Energy use for the urban water management system (drinking water and used water) is on the
order of 15 to 20 Watts/person (Daigger, 2009). This includes the energy needed for drinking
and used water treatment, and also for water conveyance (water distribution and wastewater
collection). While the energy used for treatment is significant, nearly half is used for water
conveyance. This can be compared to the available energy. For instance, the energy available in
the organic matter and nitrogen contained in the used water stream is on the order of 35 to 40
W/person (Daigger, 2009). As illustrated in Figure 1, significant heat energy is also available in
the used water stream. Coupled with reductions in conveyance energy requirements through
more integrated system configurations, the potential exists to create urban water and used water
management systems which are energy-neutral (Daigger, 2009). Table 1 summarizes a range of
currently available energy and nutrient recovery options further described in this section.
Figure 1. Thermal Energy Available in Used Water (From Daigger, 2009).
Anaerobic treatment is well known and developed. Anaerobic treatment of sludge is a well
developed and long-standing process for biologically stabilizing these solids and reducing the
level of pathogens (Grady, et al., 2011, Tchobanoglous, et al., 2002). Other types of organic
matter, including fats, oils, and grease (FOG), food waste, and industrial waste, can be added to
digesters to increase biogas production. Produced biogas can be used, after appropriate cleaning,
in CHP systems or further cleaned to remove CO2, moisture, and impurities to produce natural
gas. Although less common, used water can also be treated directly using anaerobic processes
(Grady, et al., 2011; van Haandel and Lettinga, 1994), reducing the energy required for treatment
along with producing biogas. The stoichiometry, kinetics, and methods for implementing
anaerobic processes are well known and documented (Grady, et al., 2011; WEF, 2009; van
Haandel and Lettinga, 1994).
Organic matter removed from the used water stream or produced through treatment of it can also
be treated in thermal processes, producing excess heat energy which can be used directly or for
0
5
10
15
20
0 100 200 300 400
L/(person-day)
Wa
tts/(
oC
-Pe
rso
n)
electricity production. Energy production from these materials is constrained by their water
content, as some of the heat of combustion of the organic matter must be used to evaporate this
water. Thermal processes can also be used to gasify these solids, with the gas subsequently used
for energy production. Again, these are well known processes (WEF, 2009).
Microbial fuel cells are a developing approach for directly converting the chemical energy
content of the organic matter and nitrogen contained in used water directly into electrical energy
(Logan, et al., 2006). Bacteria extract electrons from organic matter and nitrogen and transfer
them to oxygen, producing water. Extensive laboratory-scale research has been completed with
this technology, and scale-up to practical application is on-going.
Heat can be extracted directly from the flowing used water stream for a variety of purposes, such
as district heating systems. As illustrated in Figure 1, significant energy is available with only a
modest change in water temperature. One may think of this as recovering the heat added by use
of the water. Heat is removed by heat exchange and can be converted into more useful forms
using heat pumps. Although applications are currently limited, use of these technologies is
increasing.
The various biosolids land application methods result in direct recovery and reuse of the
nutrients contained in the biosolids (Daigger, 2009). Nutrient recovery and reuse by these
approaches is limited by the quantity of biosolids reused and their nutrient content. Phosphorus
can be recovered directly by a variety of technologies, for example from incinerator ash using
conventional mining technologies (Sartorius, et al., 2011). It can also be extracted from the
sludge or the recycle streams from solids processing by precipitation as struvite (MgNH4PO4) or
calcium phosphate (Ca3(PO4)2). Struvite is a high quality slow release fertilizer, and calcium
phosphate is similar to phosphate ore. Ammonia-nitrogen can be stripped from these streams
and adsorbed, for example, into sulfuric acid to form ammonium sulfate, which can be used as a
fertilizer.
Daigger (2009) described how separate distribution of potable and non-potable water can reduce
water distribution energy requirements, especially if non-potable water is produced in a
distributed fashion by rainwater harvesting and/or water reclamation. Less energy is needed for
water distribution if water is produced close to the point of use. Energy may also be saved for
treatment to non-potable compared to potable water standards. Further energy savings and
significant energy production and nutrient recovery options are created by separation of
relatively uncontaminated greywater from blackwater (toilet and kitchen wastes) and yellowater
(urine). Because it is relatively uncontaminated but represents the bulk of the used water flow,
greywater can be treated to produce significant quantities of non-potable water with relatively
low energy input. Distributed treatment of greywater further allows non-potable water to be
produced close to its use, thereby reducing the energy required for water distribution.
Blackwater contains most of the organic matter and, because it is at a higher concentration due to
greatly reduced used water flow to transport it, blackwater can be treated using anaerobic
processes for direct energy production. Yellowater contains most of the nutrients, which can be
recovered directly. Public health would also be enhanced as a disproportionate proportion of
hormones and pharmaceuticals are contained in the yellowater (Ternes and Joss, 2006).
BARRIERS TO ADOPTING ENERGY AND NUTRIENT RECOVERY OPTIONS
The question that arises from the above is, if we have all these approaches for energy reduction,
and energy and nutrient recovery, why are they not being adopted more quickly? This occurs for
several reasons, a principal one being the “siloed” nature of our educational and regulatory
systems and our institutions. Traditionally, water practitioners are educated and become
specialized in specific elements of the urban water cycle. Drinking water, storm water, used
water, and residuals management are taught separately, and it is possible for professionals to
complete their education without being learning about all elements of the urban water cycle.
This is reinforced by our professional associations which are also not comprehensive. The
regulatory framework is fragmented, with drinking water regulated separately from storm and
used water and components of the storm and used water regulations are separately and
independently implemented. Urban water management utilities are often single-purpose (water,
storm water, used water), or if they are integrated they are often internally siloed. Codes and
standards also institutionalize current practices and restrain the implementation of new practices.
It must be said, however, that these barriers are more significant with regard to water recovery
and recycling and less so with regard to energy and nutrient recovery and recycling. So, why has
progress on energy and nutrient recovery been slow?
Economic Factors
One factor has been economics. Anaerobic digestion of used water sludges with use of the
produced biogas was more widely practiced until the late 1960’s and early 1970’s when low
energy prices coupled with a focus on minimizing capital expenditures during the United States
Environmental Protection Agency (US EPA) construction grants program led to the increased
use of alternate sludge processing technologies. This situation is changing, however, as energy
prices are now increasing much faster than construction costs, making low energy using
processes more economically attractive. The economics of nutrient recovery are still generally
not favorable, although fertilizer costs are increasing more rapidly than construction costs so that
this situation is also changing. As expected, changing economics are making energy and nutrient
recovery options more cost-effective, resulting in increased adoption.
Quantifying Risks and Opportunities
The conservative nature of many engineers, coupled with the procedures used to evaluate
treatment options, constrain the application of newer technologies. The economics of various
options are typically evaluated using present worth (PW) analysis, which considers both the
capital and operation and maintenance (O&M) costs of options on an equivalent basis to select
the economically most attractive one. PW analysis is a deterministic method which assumes that
all of the cost factors are understood well enough so that the PW of each option can be estimated
comparable accuracy. This may not be the case, however for evolving and innovative
technologies and approaches compared to established ones, resulting in an inherent bias. In the
face of uncertainly about cost factors, the conservative engineer will often use conservative
values which understate the economic value of the advantages offered and overstate the
economic costs of the evolving and innovative technology or approach relative to more well
characterized conventional and proven technologies. This can be most easily thought about if
the PW analysis components are displayed as a benefit-cost ratio where the PW value of the
benefits is divided by the PW value of the costs. Understating the benefits and overstating the
costs can significantly and adversely alter the ratio compared to options where this bias is not
introduced.
The criticism here is not about recognizing the uncertainty associated with less well developed
options but the use of a deterministic analysis approaches to compare them to more well
established options. Deterministic analysis of options introduces an inherent bias when
comparing technologies and approaches at much different levels of development and also misses
the key point that the uncertainties inherent in evolving and innovative technologies and
approaches must be managed as they are being implemented. Thus, the level of risk associated
with an evolving or innovative technology or approach needs to be assessed when they are
compared to more well known and defined conventional technologies and approaches, and the
approach to implementing them refined to mitigate those risks while also maximizing the ability
to capture their inherent advantages.
Fortunately, tools are available to do this, principal among them being risk and opportunity
analysis. Risk is classically defined as the probability of occurrence of an event times its impact.
High risk elements are those which occur frequently and have large impacts, while low risk
elements occur infrequently and have small impacts. Risk and opportunity analysis also involves
determination of approaches to mitigate or take advantage of them, which can be used as the
basis for determining their economic value. Some of the key risks and opportunities of evolving
and innovative technologies and approaches are uncertain. Identification of both and
characterizing their likelihood (frequency) and economic impact allows the uncertainties inherent
in these less developed technologies and approaches to be rationally addressed.
Risk and opportunity analysis begins with identifying the most significant inherent risks and
opportunities associated with the evolving or innovative technology or approach and listing them
in a risk register, as illustrated in Table 2. Note that all options actually have important
uncertainties associated with them. If risk and opportunity analysis is to be applied to only the
evolving or innovative technologies or approaches, then only those risks and opportunities
uniquely associated with them or which are greater for them should be identified in the risk and
opportunity register. Risks and opportunities are entered into the register by first assigning a title
or number to the individual element and providing a brief description. The frequency or
likelihood (chance) of occurrence of the item is then estimated, and the impact of its occurrence
is described. Finally, methods for mitigating the resultant impact are identified, along with the
economic cost. It may seem that identifying risks and opportunities and describing them may be
relatively straightforward but that the remainder of the analysis may be difficult to accomplish as
occurrence frequencies and economic impacts are not known. The key here is to use experience
and judgment in assembling the risk and opportunity register. The simple act of assembling the
register provides significant value because the risks and opportunities are explicitly recognized
rather than inherently and implicitly incorporated into a standard PW analysis where they are not
subject to scrutiny and evaluation. Identifying mitigation measures, and their economic value,
helps to frame the importance of the identified item. If a number of items are identified, they
can be analyzed to determine a range of potential economic outcomes as will be described
immediately below. If critical risks as identified which cannot be mitigated, these may represent
fatal flaws which would prevent selection and implementation of the particular technology or
approach at the current time. This, itself, is valuable information as it provides a rational basis
for rejecting it.
Developing a preliminary risk and opportunity register provides an initial assessment of the
uncertainties uniquely associated with the subject technology or approach. The result may be a
qualitative assessment that the risks clearly outweigh the opportunities, which provides a rational
basis for eliminating it at this point. If the qualitative analysis indicates sufficient potential
advantages compared to the risks, the next step can be a Monte Carlo analysis of the economics
of the technology or approach. A Monte Carlo analysis involves using the estimated frequency
of occurrence and economic impacts of the identified items to essentially “build and operate” the
option many (1,000 to 10,000) times, thereby quantifying the inherent uncertainty. When
conducting such an analysis it is important that the PW of the option be computed on an
“expected” basis, that is, with no bias reflecting the inherent uncertainties as these are accounted
for explicitly in the risk and opportunity register. The frequency of occurrence of the various
risks and opportunities and their economic impacts are then added randomly to the “expected”
PW analysis many times, resulting in PW values which are then tabulated and a probably
distribution of the expected PW is developed. Such analyses can be easily conducted these days
with modern spreadsheets and add-ins which allow Monte Carlo analyses to be automated. The
result can then be compare to the more conventional option(s) and a decision made.
The risk and opportunity register can also be used to develop the implementation plan if the
evolving or innovative technology or approach is selected. With the key risks and opportunities
identified, an implementation approach can be developed incorporating the identified mitigation
measures. Identification of the risks and opportunities also provides a rational basis for
assigning them to the party best able to manage them (owner, technology provider, contractor,
engineer), thereby maximizing the likelihood of successful implementation.
Systematic Barriers Inherent in the Innovation Process
Systematic barriers exist in the innovation process, as defined by researchers working in a wide
variety of disciplines. The classic work in this area is by Rogers (2003) where the classic S-
curve for the adoption of innovations (or technologies) is documented. As illustrated in Figure 2,
time is required for the adoption of an innovation, with the rate being initially slow, followed by
an acceleration phase and rapid growth, with the rate of adoption slowing as saturation is
approached. Different types of adopters are predominant in various phases of the adoption cycle.
The initial adopters are termed innovators, as they simply like new things and approaches. They
provide advantage to the developer of the innovation as they are more likely to participate in the
technology development process by funding research, pilot studies, and initial installations. Next
are the early adopters, who are key to introducing the innovation to the broader potential group
of adopters. They are continuously seeking advantage and are generally able to identify and
implement innovations which provide it to them. As a consequence, they are closely watched by
their peers and, when they select and successfully implement an innovation, adoption by the
early majority adopters often follows as they are also looking for advantages but generally let the
early adopters do the hard work of searching out and further developing beneficial innovations.
The late majority and laggards follow, but mainly out of necessity. The key point is that this
range of adopters exists in every population, including in the water profession.
Figure 2. The S-Curve for the Adoption of Innovations (Adapted from Rogers, 2003).
Christensen (2003) and Christensen and Raynor (2003) provide further insight into the
innovation process through their study of the adoption of technology in the electronics industry.
As illustrated in Figure 3, both customer expectations for improved functionality of the
technology or innovation and the capabilities of the technology evolve with time. Expectations
are often first dominated by interest in performance, but as performance is established and
becomes expected differentiating factors for the subject technology evolve from reliability to
convenience to price (at which time the subject technology has become a commodity). Early in
the cycle for a sustaining technology or innovation the difference between the functionality
provided and that desired by the user drives (funds) further development. As also illustrated in
Figure 3, not all users are the same and have different desires with regard to performance,
reliability, convenience, and price. This is an important factor which allows different “products”
to co-exist in the marketplace at any given time – different products serve the desires of different
customers. However, the functionality of the product can evolve to where it begins to exceed
that desired by the customer. As this happens, the opportunity to enter the marketplace is created
for an alternative technology or innovation which begins to meet the needs of some of the
customers and establishes itself in this set of applications.
Figure 3. Sustaining and Disruptive Innovations.
The technology development, or learning, curve has been quantified for a number of
technologies, but some of the most consistent data are available for the energy sector. Figures 4
and 5 provide illustrations, using the unit cost of various energy production technologies as the
performance metric. Figure 4 illustrates the classic observation that performance improves
exponentially with increased installed capacity, reflecting the learning which occurs with use of
the technology. The rate is greatest during the initial development phases (described in greater
detail below), and then decreases as the technology proceeds into the commercialization phase.
Figure 4. Decrease in Costs for Gas Turbines with Installed Capacity (From Grübler, et
al., 1999).
As illustrated in Figure 5, competing technologies follow similar learning curves, and that
learning can occur at similar rates for competing technologies. Given the relationships presented
in Figure 5 one may wonder how competing technologies, such as photovoltaics, become
established when their unit costs are systematically higher than competing technologies such as
windmills and gas turbines. The answer is that, initially, the various technologies fill various
niches. Thus, photovoltaics may initially be used in remote installations where their passive
operation is an advantage. More on this later as well.
Figure 6 illustrates that competing technologies may evolve for an extended period, filling
specific niches but not becoming a significant contributor to meet the overall need for some time.
The term that is applied to this phenomenon is materiality – meaning when the contribution of a
particular technology to meeting industry-wide demands becomes material from a quantitative
perspective. That time is needed for a technology (or innovation) to become material results
from a number of factors. One is the fact that time is needed for the technology to evolve
through the learning curve. The second is that, in some industries, the life of the installed
infrastructure is quite long and, unless the new technology is sufficiently superior to existing
technologies to justify its early replacement, existing technology must reach its useful life before
it is replaced by newer approaches. These constraints certainly apply to the water industry.
Figure 5. Evolution of Unit Costs for a Variety of Competing Energy Technologies as a
Function of Installed Capacity (Grübler, et al., 1999).
Table 3 is abstracted from Grübler, et al., 1999 and summarizes and extends the concepts
presented thus far. The processes of invention and innovation are first distinguished. Invention
is the discovery of some unique and fundamental phenomenon that may have no practical value
in and of itself but which forms the basis for value-added practical applications. Invention is a
random and unpredictable process which is often the result of basic research. The cost can be
high, it does not lead directly to a marketable product (or usable result), and little learning occurs
relative to practical applications. In contrast, innovation is the process of applied research,
development, and demonstration (RD&D) which builds on the invention but seeks to develop a
useful product or result. Again, costs are high, and no marketable or useful result is produced.
Innovation leads to the development of prototype products which begin to fill niche applications,
as illustrated in Figure 3. This represents the initial phase of adoption by the innovators, as
illustrated in Figure 2. This phase is characterized by a high rate of learning by doing and close
collaboration between technology suppliers and users. Development costs are still high but are
declining, and revenue from sales begins to help finance some of the development costs. The
practical learning rate is high.
Figure 6. Time is Required for Niche Technologies to Become Material Relative to the
Needs of the Entire Industry (From Kramer and Haight, 2009).
Once niche applications are established, learning by doing progresses, leading to progressive
improvements which expand the available market, as illustrated in Figure 3, and adoption
proceeds as characterized in Figure 2. Costs decline rapidly as market share grows quickly, but
the learning rate declines as the technology matures. The rapid growth phase is followed by
market saturation and finally by senescence as it begins to be replaced by higher performing
technologies.
OVERCOMING BARRIERS TO ADOPTING ENERGY AND NUTRIENT RECOVERY
OPTIONS
As noted, economics are becoming more favorable for the adoption of innovative and evolving
energy reduction and energy and nutrient recovery technologies and approaches. While
systematic barriers restrain the adoption of energy and nutrient recovery options by the water
profession, systematic changes could reduce these barriers, as follows:
1. Revise the educational system so that urban water management is taught in a more
complete and holistic fashion. The recently published Body of Knowledge (BOK) by the
American Academy of Environmental Engineers (AAEE) should help to accelerate this
(AAEE, 2009).
2. Greater collaboration by the relevant professional societies, including the American
Water Works Association (AWWA) and the Water Environment Federation (WEF).
3. Aggressively working through the relevant professional societies to revise codes and
standards to make them less prescriptive and more performance-based.
4. Working with regulators and legislatures to develop more holistic environmental
legislation and translating both existing and revised legislation into more holistic
environmental regulations which encourage innovation. Transitioning from prescriptive
regulations which dictate practices to performance-based regulations which dictate what
must be accomplished illustrate the types of changes that can be made. Incentives would
ideally be incorporated into revised regulations which encourage new, higher performing
technologies and approaches and reward innovators and early adopters.
5. Revise the procedures typically used to evaluate evolving and innovative technologies
and approaches relative to the more well established and defined conventional
technologies to explicitly reflect the greater uncertainty inherent with evolving and
innovative technologies and approaches.
6. Recognize the inherent nature of the innovation process and the steps that are necessary
for new inventions and innovations to become commercially viable. One of the inherent
constraints to innovation in the water industry is the long life for infrastructure and
equipment conventionally used. A higher rate of innovation would occur if it was
recognized that a greater rate of obsolescence would allow beneficial technologies and
approaches to become available more quickly, which in the long-run would improve
performance and lower costs more rapidly.
REFERENCES
American Academy of Environmental Engineers (2009) Environmental Engineering Body of
Knowledge, American Academy of Environmental Engineers, Annapolis, MD.
Christensen, C. M. (2003) The Innovator’s Dilemma: The Revolutionary Book That Will Change
the Way You Do Business, HarperCollins Publishers Inc., NY.
Christensen, C. M. and R. E. Raynor (2003), The Innovator’s Solution: Creating and Sustaining
Successful Growth), Harvard Business School Publishing, Boston.
Daigger, G. (2010) Integrating Water and Resource Management for Improved Sustainability In
Water Infrastructure for Sustainable Communities, Hao, X., V. Novotny, V. Nelson, Ed., IWA
Press, London.
Daigger, G. T. (2009) State-of-the-Art Review: Evolving Urban Water and Residuals
Management Paradigms: Water Reclamation and Reuse, Decentralization, Resource Recovery.
Water Environment Research, 81(8), 809-823.
Daigger, G.T. (2007) Wastewater Management in the 21st Century. Journal of Environmental
Engineering, 133(7), 671-680.
Daigger, G. T. and Crawford, G. V. (2007) Enhanced Water System Security and Sustainability
by Incorporating Centralized and Decentralized Water Reclamation and Reuse Into Urban Water
Management Systems. J. Environ. Eng. Manage., 17(1), 1-10.
Daigger, G. T. (2003) Tools for Success Wat. Environ. Tech., 15(12), 38-45.
Guest, J. S., S. J. Skerlos, G. T. Daigger, J. R. E. Corbett, and N. G. Love (2010) The Use of
Qualitative System Dynamics to Identify Sustainability Characteristics of Decentralized
Wastewater Management Alternatives. Water Science and Technology, 61(6), 1637-1644.
Grady, C. P. L., Jr., G. T. Daigger, N. G. Love, and C. D. M. Filipe (2011) Biological
Wastewater Treatment, CRC Press, Boca Raton, FL.
Guest, J. S.; Skerlos, S. J.; Barnard, J. L.; Beck, M. B.; Daigger, G. T.; Hilger, H.; Jackson, S. J.;
Karvazy, K.; Kelly, L.; Macpherson, L.; Mihelcic, J. R.; Pramanik, A.; Raskin, L.; van
Loosdrecht, M. C. M.; Yeh, D.; Love, N. G. (2009) A New Planning and Design Paradigm to
Achieve Sustainable Resource Recovery From Wastewater. Environmental Science &
Technology. 2009, 43(16).
Grübler, A. N. Nakićenović, D. “G. Victor (1999) Dynamics of Energy Technologies and Global
Change, Energy Policy, 27, 247-280.
Jimenez, B. and T. Asano (2008) Water Reuse: An International Survey of Current Practice,
Issues and Needs, IWA Publishing, London.
Kramer, G. J. and M. Haight (2009) No Quick Switch to Low-Carbon Energy, Nature, 462(3),
568-569.
Logan, B. E., Hamelers, B., Rozendal, R., Schroder, U., Keller, J., Freguia, S., Aelterman, P.,
Verstraete, W., and Rabaey, K. (2006) Microbial Fuel Cells: Methodology and Technology
Envir. Sci. Tech., 40(17), 5181-5192.
Rogers, E. M. (2003) Diffusion of Innovation, 5th
Edition, Free Press, NY.
Sartorius, C., J. van Horn, and F. Tettenborn (2011) Phosphorus Recovery From Wastewater –
State-of-the-Art and Future Potential Proceedings of Nutrient Recovery and Management 2011,
January 9-12, 2011, Miami, FL., CD-ROM, Water Environment Federation, Alexandria, VA.
Tchobanoglous, G. F. L. Burton, and H. D. Stensel (2002) Wastewater Engineering: Treatment
and Reuse, McGraw Hill, Boston.
Ternes, T. A. and A. Joss (2006) Human Pharmaceuticals, Hormones and Fragrances: The
Challenge of Micropollutants in Urban Water Management, IWA Publishing, London.
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Ltd., London.
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Manual of Practice No. 8, 5th
Edition, Alexandria, VA.
Table 1. Summary of Select Energy and Nutrient Recovery Options.
Technology Description Development Status Contribution to Sustainability
Anaerobic Treatment
Wastewater Raw municipal used water or a
component of it is treated directly in a
high-rate anaerobic process.
Technology developed and
applied in warm climates but not
in colder climates
Energy for treatment reduced and
collected biogas usable for energy
production
Sludge Sludges from conventional used water
treatment stabilized in anaerobic
digesters
Conventional mesophilic
digestion well established;
advanced digestion processes
evolving
Biogas production from treatment
residuals
Thermal
Treatment
Residuals from conventional used water
treatment treated in thermal processes
with excess heat captured for direct use
and/or energy production
Thermal destruction technology
well established; gasification
technology established but
evolving
Thermal energy used directly and/or
for energy production
Microbial
Fuel Cells
Chemical energy in used water directly
converted to electricity by combined
biological and electrochemical
processes
Science well developed; scale-up
to pilot and eventually to
commercial scale on-going
Energy for treatment avoided and
electrical energy produced directly
Heat
Recovery
Heat exchangers used to collect heat
from used water and heat pumps used,
when necessary, to produce usable
heated source
System components well proven;
limited but growing number of
full-scale applications
Heat energy removed from used water
provides direct domestic, commercial,
and industrial functions
Biosolids
Land
Application
Residuals from conventional used water
treatment processed into wide variety of
products which are applied to land as
fertilizer and/or soil conditioner
Wide variety of well developed
and widely used processes such
as land application of digested
biosolids, composting, thermal
drying
Nutrients contained in applied
biosolids provide nutrients for plant
growth and off-set use of conventional
fertilizer
Phosphate
Recovery
Phosphate recovered from used water,
sludge, or solids handling recycle stream
in reusable form
Evolving set of technologies
generally applied to sludge or
solids handling recycle streams
Use of recovered phosphate replaces
use of phosphate produced from
mined phosphate ore
Nitrogen
Recovery
Ammonia-nitrogen is removed from
liquid stream by air stripping and
subsequently adsorbed into sulfuric acid
Well established process which is
little applied today due to
unfavorable economics
Produced ammonium sulfate usable
directly or as component of
commercial fertilizer
Dual
Distribution
Potable and non-potable water
separately produced and distributed to
the customer
Well developed approach which
is widely used in water short
locations
Less energy required to produce non-
potable water from compromised
sources
Source
Separation
Greywater, blackwater, and yellowater
separately collected and processed
Evolving approach which is being
applied in increasing number of
locations
Water, energy, and nutrients in used
water separately collected and
recovered
Decentralized
Systems
Used water treated locally for
reclamation and reuse
Evolving approach which is
increasingly being applied
Energy for reclaimed water
distribution reduced
Table 2. Example Risk and Opportunity Register.
Item
Description
Frequency or Chance
of Occurrence
Impact Mitigation Method Economic Impact of
Mitigation
#1 Item #1 Description Chances for Item #1 Impact of Item #1 Item #1 Mitigation Cost to Mitigate Item #1
#2 Item #2 Description Chances for Item #2 Impact of Item #2 Item #2 Mitigation Cost to Mitigate Item #2
#3 Item #3 Description Chances for Item #3 Impact of Item #3 Item #3 Mitigation Cost to Mitigate Item #3
#4 Item #4 Description Chances for Item #4 Impact of Item #4 Item #4 Mitigation Cost to Mitigate Item #4
Table 3. Stages of the Innovation Process (Abstracted from Grübler, et al., 1999)
Stage Mechanism Cost Market
Share
Learning
Rate
Invention Random Breakthroughs and Basic Research High 0 % -
Innovation Applied Research, Development, and Demonstration (RD&D) High 0% -
Niche
Market
Niche Applications, Learning by Doing, Suppliers and Users Have
Close Relationship
High But
Declining
0-5% 20-40%
Pervasive
Diffusion
Standardization, Mass Production, Economies of Scale, Network
Effects
Rapidly Declining 5-50% 10-30%
Saturation Commodity, Intense Competition Low and Declining Up to 100 % 0-5%
Senescence Few Improvements Possible Low and Declining Declining 0-5%