Solid Waste Engineering & Management

SOLID WASTE MANGEMENT

Human activities generate waste materials that are often discarded because they are considered useless. These wastes are normally solid, and the word waste suggests that the material is useless and unwanted. However, many of these waste materials can be reused, and thus they can become a resource for industrial production or energy generation, if managed properly.

Sources of Solid Wastes in a Community

Functional Elements of a Solid Waste Management System

Waste generation Waste generation encompasses those activities in which materials are identifiedAs no longer being of value and are either thrown away or gathered together for disposal. What is important in waste generation is to note that there is anIdentification step and that this step varies with each individual. Waste generationis, at present, an activity that is not very controllable.

Waste handling and separation, storage, and processing at the source

Waste handling and separation involve the activities associated with managingwastes until they are placed in storage containers for collection. Handlingalso encompasses the movement of loaded containers to the point of collection.Separation of waste components is an important step in the handlingand storage of solid waste at the source. On-site storage is of primary importancebecause of public health concerns and aesthetic considerations.

CollectionCollection includes both the gathering of solid wastes and recyclable materialsand the transport of these materials, after collection, to the location wherethe collection vehicle is emptied, such as a materials-processing facility, atransfer station, or a landfill.

Transfer and transport The functional element of transfer and transport involves two steps: (1) thetransfer of wastes from the smaller collection vehicle to the larger transportequipment, and (2) the subsequent transport of the wastes, usually over longdistances, to a processing or disposal site.The transfer usually takes place at atransfer station. Although motor vehicle transport is most common, rail carsand barges are also used to transport wastes.

Separation, processing, and transformation of solid waste

The means and facilities that are now used for the recovery of waste materialsthat have been separated at the source include curbside collection and drop offand buyback centers.The separation and processing of wastes that havebeen separated at the source and the separation of commingled wastes usuallyoccurs at materials recovery facilities, transfer stations, combustion facilities,and disposal sites.Transformation processes are used to reduce the volume and weight of wasterequiring disposal and to recover conversion products and energy.Theorganic fraction of MSW can be transformed by a variety of chemical andbiological processes.The most commonly used chemical transformation processis combustion, used in conjunction with the recovery of energy.The mostcommonly used biological transformation process is aerobic composting.

Disposal

Today, disposal by landfilling or landspreading is the ultimate fate of all solidwastes, whether they are residential wastes collected and transported directlyto a landfill site, residue from the combustion of solid waste, compost, or other substances from various solid waste processing facilities. A modern sanitary landfill is not a dump. It is a method of disposing of solid wastes on land or within the earths mantel without creating public health hazards or nuisances

Types of Solid Wasteswith Physical, Chemical & Biological Properties

Types of Solid Wastes Paper Category Plastic Category Glass Category Metal Category Yard Waste Category Organic Category Other Waste Category Special Waste Category

Paper Category Mixed Paper Newspaper High Grade Ledger Paper Non Recyclable PaperPlastic Category Polyethylene tri-phthalate containers (PET no. 1) High density polyethylene containers (HDPE no. 2) Polyvinyl chloride containers (PVC no. 3) Low density polyethylene (LDPE no. 4) Poly propylene (PP no. 5) Polystyrene (PS no. 6) Other plastics (other no. 7)Glass Category Recyclable Glass Non Recyclable GlassMetal Category Aluminum Cans Ferrous Metals Non Ferrous Metals White GoodsYard Waste Category Yard WasteOrganic Category Organic Compactable Organic Non Compactable Tires & Rubber Wood Waste

Other Waste Category Inert Slides (Inert Wastes) Household Hazardous WastesSpecial Waste Category Sewerage Sludge Other Special Wastes

Physical Properties Composition Of MSW Moisture Content Generation Of Solid Waste Density Of Solid Waste Particle Size Distribution Field Capacity Permeability Of Compacted Waste

Composition of MSW By composition we mean components of solid waste by % wt. Varies with location, season, economic conditions Food waste, largest component in low income countries, being not trimmed & absence of grinder. Percentage of plastic waste and paper waste is increasing with the passage of time.

Moisture Content Expressed in two ways Wet weight measurement (% wet weight of material) Dry weight method (% dry weight of material) Wet weight commonly used in SWM Moisture content of samples analyzed in lab.m = w d x 100WWhere,M = moisture contentW = initial wt of sample, (kg)D = weight of sample drying at 105oc (kg)

For food & yard waste, various 15-40%, Plastic & inorganic, 3%

Generation of Solid Waste Expressed in per capita. 0.65 kg/c/day in 2002. (for RawalpindiCity) Assumed to be continue for next ten years. Total generation, 713 tons per day. (For RawalpindiCity)Physical Composition of Solid Waste of RawalpindiCity by Random Sampling Techniques

Sample LocPandora ChongiBlock-EBlock-EChungiNo.8BnyChowk6th RoadCollageRoadS.S RdV.N CollageAvgas

AreaPoor CommunityRich CommunityRich CommunityPoor CommunityPoor CommunityRich CommunityMiddle IncomeMiddle IncomeMiddle Income

Food Waste58.960.558.353.355.757.856.459.455.557

Plastic6.25.66.25.58.35.75.56.66.66

Card/ Paper3.65.33.33.95.35.33.92.82.74

Rags3.34.24.44.44.84.76.83.94.24

Wood6.02.22.26.34.21.61.61.62.83

Total Organic7877.874.473.478.375.174.274.371.874

Metal15.214.113.814.716.913.212.712.214.314

Other6.88.111.611.74.811.713.113.513.912

Total In-Organic2222.225.626.621.724.925.825.728.226

GrandTotal100100100100100100100100100100

Density of SW Specific wt, expressed in material per unit volume, lb/yd3 Data needed to assess total mass & volume of solid waste Vary with location, season & length of time in storage

Particle Size Distribution Important consideration in recovery (recycling & reuse) of material, especially with mechanical means such as magnetic separators. Relevant to incineration & biological transformation methods. Largest dimension is up for sizing facilities like conveyor belts & grinders etc. Shredders & separators are used to reduce to desirable sizes for treatment of composting etc.

MSW Generation Rate for RawalpindiCity for the Years (2003-2013)

YearPopulationGeneration Rate

Kg/Capita/DayDaily (tons)Yearly (tons)

200311,34,2120.65737.242,28,544

200411,75,0440.65763.772,36,768

200512,17,3460.65791,272,45,294

200612,61,1700.65819.762,54,125

200713,06,5720.65849.272,63,273

200813,53,6090.65879.842,72,750

200914,02,3390.65911.522,82,571

201014,52,8230.65944.332,92,742

201115,05,1250.65978.333,03,282

201215,59,3090.651013.553,14,200

201316,13,8840.651049.033,25,197

Field Capacity Total amount of moisture that can be retained in a waste sample subject to downward pull of gravity. Water in excess of field capacity will be released as leachate Field capacity varies with the degree of applied pressure & state of decomposition of the waste. Field capacity of un-compacted commingled wastes from residential & commercial sources, 50-60%.

Permeability of Compacted Waste Hydraulic conductivity governs the movement of liquids & gases in landfill. Sludge in landfills tends to resist the movement of water down through then due to low hydraulic conductivity by virtue of very high moisture content. Instead, rainfall is converted to surface runoff & sludge material is transported to surface streams. Paper & packaging has no resistance to rain in filtration Hydraulic conductivity of soil governs the transport rate of leachate within the solid waste fill.

Chemical Composition of MSWChemical composition is important in evaluating alternative processing & recovery options.If solid wastes to be used as fuel, four most important properties to be known are: Proximate analysis Fusing point of ash Ultimate analysis (major elements) Energy content

Where organic fraction of MSW to be composted or to be used a feedstock for the production of other biological conversion products, not only will information on the major elements (ultimate analysis) that compose the waste be important, but also information will be required on the trace elements in the waste.

Proximate Analysis Proximate analysis for combustible components of MSW included following tests: Moisture content by % wt (loss of moisture when heated to 1050c for 1 hr) Volatile combustible matter (loss of wt on ignition at 9500c in a covered crucible) Fixed carbon (combustible residue left after volatile matter is removed) Ash (wt of residue after combustion in an open crucible)

Fusion Point of Ash Temperature at which ash resulting from the burning of waste will form a solid (clinker) by fusion & agglomeration. Typical fusion temp ranges from 2000-2200F (1100-1200 C)

Ultimate Analysis of SW Components Determination of percent of C, H, O, N, S & Ash Used to characterize the chemical composition of the organic matter in MSW Use to define proper mix of waste materials to achieve suitable C/N ratios for biological conversion processes

Energy Contents of SW Components Can be determined by using a full scale boiler as a calorimeter By using a lab bomb colorimeter. By calculation, if elemental compose is known

Potentially critical element in incineration can be measured or calculated usingDuLong Formula:

Btu/lb = 145C +610(H -1/8 O) + 40S +10N

Btu per lb on a dry ash-free basis is btu/lb (dry ash-free) = btu/lb (as discarded) Approximate btu values for indle waste material can be determined by using modified dulong formula. Btu/lb = 145c+610 (h2-1/8 o2)+40s+10n Constituents are % by weight.

Biological Composition of MSW Excluding plastic, rubber & leather components organic fraction of most MSW can be categorized as follows: Water soluble constituents-as sugars, starches, amino acid & various organic acids Hemi cellulose-a condensation product of 5 or 6-carbon sugars. Cellulose a condensation product of 6-carbon sugar glucose Fats, oils & waxes, which are esters of alcohols & long-chain fatty acids. Lignina polymeric material containing aromatic rings with methoxyle groups (-OCH3), the exact chemical nature of which is still not known Lignocelluloses-a combination of lignin & cellulose. Proteins-composed of chains of amino acids. Almost all organic fraction of MSW can be converted biologically to gases & relatively inert organic & inorganic solids. Production of orders & generation of flies are related to put risible nature of organic material found in MSW.

Bio Degradability ofOrganic Waste Biodegradation can be aerobic or anaerobic. Volatile slides contents, determined by ignition at 5500C, are often used as a measure of degradability of organic fraction of MSW. Use of VS in describing the biodegradability of organic fraction is misleading as some constituents are highly volatile but low in biodegradability. Alternatively, lignin content of a waste can be used to estimate the biodegradable fraction, as:BF = 0.83 0.028 LCBF = biodegradable fraction expressed on a VS basis0.83 0.028 = Empirical ConstantLC = Lignin content of VS, expressed as a % by wt.

Production of Odor Develop when SW stored for long periods of time on site More significant in warm climates Typically, results from the aerobic decomposition of the organic components found in MSW.

Breeding of Flies In warm climate, it is an important phenomenon. Flies develop in less than two weeks. Maggot (larval) once develop, difficult to remove, & can develop to flies.

Types of Solid Waste Collection System

The Detail Comparison of Haul Container Systemand StationaryContainer System

Collection System After the generation, the solid waste is picked up according to a collection system. In the last decade several systems are used for the collection of solid waste. A variety of equipment used for the solid waste collectionTypes of Collection systemsCollection systems may be classified w.r.t. Mode of operation The equipment used Types of wasteMode of operation According to mode of operation, the collection system classified into two categories viz ; Haul Container System (HCS) Stationary Container System (SCS)

Haul Container System (HCS)

DefinitionThese are collection systems in which the CONTAINERS used for the storage of waste are: Hauled to the disposal site Emptied and Returned to their original location or some other location.Types of Haul Container SystemThere are three main types of Haul Container Systems: Tilt-frame Container Systems Trash-trailer. Hoist-Truck

Stationary Container System (SCS)These are collection systems in which the CONTAINERS used for the storage of waste are: Remain at the point of generation, except for Occasional short trips to the collection vehicle for empty.

Types of Stationary Container SystemThere are two main types of Stationary Container Systems: Systems in which Self loading compactors are used Systems in which Manually loading vehicles are used

Typical Data on Vehicles Used for the Collection of Solid Waste

Labor Requirement HAUL CONTAINER SYSTEM (HCS) Single collector is used For safety (in some cases) driver and helper are deployed For hazardous waste driver and helper always be deployed

Stationary Container System (Mechanically Loaded) Single collector is used For container mounted on roller, driver and helper are brought into play. In congested ,inaccessible locations driver and two helpers are used

Stationary Container System (Manually Loaded) Number of collectors varies from 1 to 3. Single collector for curve and alley service generally used. Multi person crew is used for backyard carry service.

Comparison of HCS & SCS w.r.t. Merits & Demerits

HCS

SCS

Unsightly & unsanitary conditions: Less with use of large container.

Unsightly & unsanitary conditions: More with use of numerous smaller containers.

Utility of driver: Less as spend more time in driving.

Utility of driver: is greater as to collect several containers

Time: Handling time reduced

Time: Accumulative handling time is more but trip to disposal site time is saved.

Suitability:Ideally suitable where SW rate of generation is higher. Suitable for all types of wastes

Suitability: Suitable where SW quantity is less and generation points are more. Suitable for all types of wastesexcept Heavy Industrial Waste & Bulk Rubbish

Container size: Large

Container size: Small

Flexibility: Containers of many different sizes & shapes are available for all types of SW

Flexibility: The use of smaller containers offer greater flexibility in terms of shape, ease of loading & special features available.

Utilization of containers: Use of large containers often leads to low volume utilization, unless loading aids (platform, ramps etc.).

Utilization of containers: can be increased by using small, easier to load, containers.

Data for Computing Equipment and Labor Requirement

SCS Source Separation-multicompartment Wheeled Container

SCS Source Separation-multicompartment Wheeled Container

SCS (Mechanically Loaded Truck)

HCS Tilt-frame Container Loading Mechanism

Solid Waste Systems in Pakistan

Masonry Bin

Open Body Truck

Hoist ContainerHoist Truck

Metal Container

Animal Cart

Transfer Stations Alternative to direct haul Justified when cost to transport waste from generation point to disposal site is greater than cost to transport from generation point to transfer station plus haul to the disposal site

Benefits Large trailers replace many collection vehicles Get collection vehicles back to work rapidly Locate disposal site far from population areas Opportunity to inspect waste Opportunity to process waste Use multiple disposal sites

Need Presence of illegal dumps and litter Remote disposal sites Small capacity collection vehicles Low density residential areas

Types Direct discharge waste pushed into open trailers Storage pit tip onto floor, into hoppers to compactor that pushes waste into vehicle.

Transfer Station Tipping FloorCompactor

Surge Pit

Open Top Transfer Trailers

Compactor System

Pre-compactor SystemBalerIntermodal Container System

Composting

IntroductionComposting is an anaerobic process in which the micro-organisms, in an oxygen environment, decompose the organic food waste as a result minerals and humus are obtained as a final product. Key Inorganic Nutrients nitrogen phosphorus sulphur potassium magnesium calcium sodium

Process Requirements Key Inorganic Nutrients Temperature Moisture content Oxygen C/N ratio Microbes pH Biochemical composition and texture

Temperature Psychrophilic15 o to 20o C Mesophilic25 o to 35o C Thermophilic50 o to 60o CMoisture content Compost should be kept moist, but not soggy At the ideal moisture level, 50-60% Oxygen Optimum oxygen levels are 15 to 20 per cent At the ideal moisture level, 50-60% Composting inhibits at oxygen less than 10 per cent (by volume). Turning and ventilating compost are meant to keep the oxygen content at a sufficient level.

C/N Ratio: Nitrogen is required for cell synthesis. Carbon is used as energy source Optimum C/N ratio is 30 Composting operates down to C/N Ratios of 20 Materials that are a good source of nitrogen are called "Greens Materials that are high in carbon are called "Browns"

Carbon/Nitrogen Ratio of some Waste Material

Material% nitrogen (dry)C/N Ratio

Fish Scrap6.5-10-

Farm Yard Manure2.1514-1

Kitchen waste2.025-1

Seaweed1.9219-1

Wheat Straw0.32128-1

Rotted Sawdust0.25200-1

Raw Sawdust0.11510-1

Food Waste2.0-3.015-1

Total Refuse0.5-1.430/80-1

Microbes: Psychrophiles - the low temperature bacteria Mesophiles - the medium temperature bacteria Thermophiles - the high temperature bacteria

pH optimum pH range is 6 to 8Biochemical composition and texture: composition of waste influence the process rate Reducing the particle of the raw material will in crease the rate of composting.

Composting systems Traditional Wind-row. Aerated static pile In-Vessel Composting

Traditional Wind-row. 1~2 meter high. Takes about 3 months

Aerated Static Pile: 1~2 meter high, 3~ 4 meters wide and about 20 meter long laid on floor of ventilation pipe system Covered with stabilized compost Takes about 4~6 weeks.

In-Vessel composting

Environmental Benefits Compost enriches soils Compost helps cleanup contaminated soil Compost helps prevent pollution Using compost offers economic benefits

Problem with Composting Heavy Metals Mercury Cadmium Copper Zinc

Worm CompostingWorm composting is using worms to recycle food scraps and other organic material into a valuable soil amendment called vermicompost, or worm compost. Worms eat food scraps, which become compost as they pass through the worm's body. Compost exits the worm through its' tail end. This compost can then be used to grow plants. To understand why vermicompost is good for plants, remember that the worms are eating nutrient-rich fruit and vegetable scraps, and turning them into nutrient-rich compost.

Materials to be Used or Avoided in a Worm Composting Bin. Worms have been hard at work breaking down organic materials and returning nutrients to the soil. Though worms can eat any organic material, certain foods are more palatable for composting purposes. Raw fruits and vegetable scraps are recommended mostly for worm composting at small scales. Stay away from meats, oils and dairy products, which are more complex materials than fruits and vegetables. Thus, they take longer to break down and can attract pests. Cooked foods are often oily or buttery, which can also attract pests.

Setting up a Worm Bin Setting up a worm bin is easy. All you need is a box, moist newspaper strips, and worms. To figure out how to set up a worm bin, first consider what worms need to live. If the bin provides what worms need, then it will be successful. Worms need moisture, air, food, darkness, and warm (but not hot) temperatures. Bedding made of newspaper strips or leaves, will hold moisture and contain air spaces essential to worms. Use red worms or red wigglers in the worm bin. The scientific name for the two commonly used red worms is Eiseniafoetida and Lumbricusrubellus.

Harvesting Harvesting means removing the finished compost from the bin. In a favorable environment worms will work tirelessly to eat the "garbage" and produce compost. As time progresses, bedding will reduce and compost will increase in the bin. After 3-5 months, when bin is filled with compost (and very little bedding), it is time to harvest the bin. To prepare for harvesting, do not add new food to the bin for two weeks. Then remove compost from the bin by using appropriate methods of harvesting.

Using Worm Compost Compost can be used immediately after harvesting or it can be saved for the gardening/farming season. The compost can be directly mixed with soil or garden soil as a soil amendment, which helps make nutrients available to plants. Or, the compost can be used as a top dressing fro the fields or plant pots. Compost Tea can also be made with compost by Simply adding 1-2of compost or in suitable proportions to water. Allow compost and water to "steep" for a day, mixing occasionally. Then water plants/farms. The resulting "tea" helps make nutrients already in the soil available to plants.

A Step By Step Photo Guide to Home worm Composting:

Home worm bin with lid, Strip up the newspaper for bottom tray and air vent bedding and spread it.

Bedding in Bin.Add dry leaves and fluffs up the mixture

Add a handful of sand and soil.Add waters the mix

500 red wriggler worms areRaw veggies and fruit, coffeeplaced on top. grounds, tea bags and egg shells go in.They crawl to the bottom.

Open a hole in the bedding in The fork marks the corner. Feed a d one corner and deposit food.differentcorner every week.

Finished compost can be To harvest, put compost in piles. expected in 3-4 month Under light. Worms move center

Remove worms from compost. Place worms in fresh bedding and start again.

Design of Sanitary Landfill Site

Site PreparationsThe following steps should be taken immediately for the detail design of the proposed site and are essential to develop and start the actual treatment process. Topographic survey of the site. Detail leveling of the site. Contour plan. Cutting of the 150mm top soil of the whole area and saving it for earth cover over the solid waste. Preparing site for proper drainage of rain water by cutting of high level ground and giving it a down slope (1:400) soil obtained from this cutting is used in providing embankment for fencing of the area. Construction of all weather roads of 5m width, to facilitate easy approach of trucks to all points at site. Providing infrastructure with all accessories, a watchman hut with attached toilet, WeightBridge, wash trough (3 x 5 x 10m) and a vehicular as well as a pedestrian entrance gate. Proper fencing on the top of the embankment towards the exterior side.

Parameters Adopted for Design All the calculations will be based on the population of the city and the same can be projected for the land requirements till the end of the design period. It is considered that 30% of the waste generated is land filled, 60% is composted, while the remaining 10% is recycled. Waste will be compacted in four layers, one below the ground level and three above the ground level. Depth of each later will be 2m. Excavated soil will be used as cover material. Cover will be 0.15m for intermediate layers while final layer will be covered by 0.6m (2ft) of cover material. Excavation for one year will be made in advance A bond will be provided in each layer after one year. Waste will be compacted to density of 1000 to 1300 Kg/m3. Embankments will be provided at the periphery, high enough to enclose the site with the fencing mounted on top. One standard size of cell will be adopted considering the width of the compactor and the tractor blade.

ProblemsProblemThe Town of Waytogo, population 56,789, has decided to burn its as collected MSW which amounts to about 6 lb/capita.day. Find how many barrels of oil they save on a daily basis. Energy of as collected MSW is 4600 Btu/lb.1bbl oil = 5.8x106BTUSolutionEnergy in the MSW = 4600 Btu/lb x 56,789 cap x 6 lb/capita.dayEnergy in the MSW = 1.57 x 109 BtuOil Barrel saved = 1.57 x 109 Btu / 5.8x106BTUOil Barrel saved = 270 barrels/day

Problem (Home separation and curbside collection of recyclables)A community is purchasing specialized vehicles for the curbside collection of source-separated wastes. Three recycling containers are to be provided to each residence and residents will be asked to separate newspapers and cardboard, plastics and glass, and aluminum and tin c ans. the homeowner is to place the separate materials in the appropriate containers and then move the recycling containers to curbside once per week for collection by special recycling vehicles. Estimate the relative volumetric capacity required for each material in recycling collection vehicles. Assume 80% of the recyclable material will be separated and that newsprint represents 20% of the total paper waste. The number of homes that will participate in the separation program is estimated to be 60%. if the separated wastes are to b e collected from a subdivision of 1200 homes, determine the number of trips that will be required if the size of the collection vehicle is 15 cubic yard. Assume 3.5 residents per home.

ComponentsTotal solid wastelbsSpecific weightlbd/ft3

Food Waste8.018.0

Paper35.85.6

Cardboard6.43.1

Plastics6.94.1

Textiles1.84.1

Rubber0.48.1

Leather0.410.0

Yard Waste17.36.3

Wood1.814.8

Glass9.112.2

Tin cans5.85.6

Aluminum0.610.0

Other metals3.020.0

Dirt, Ash, etc2.730.0

Total100.00

SolutionFirst of all rearrange the table to calculate the relevant volume of recycled material. By the given statement that 80% recycled material will be recovered but in the case of news prints the %age given is 20 % of that 80% recovered material. Thus we use 80% in all other cases but we will take 20% of that 80% in the case of newsprints. Now calculate the relative volume of the recycled materials: Newspaper + cardboard = 1.02 + 1.65 = 2.67 ft3 Plastics + glass = 1.34 + 0.60 = 1.94 ft3 Aluminum + tin cans = 0.82 + 0.05 = 0.87 ft3Now we will calculate the volume of required components in 15 yd3 vehicle. Volume of newspapers + cardboard = (2.67/5.48) x 15 = 7.3 yd3Volume of Plastics + glass = (1.94/5.48) x 15 = 5.3 yd3Volume of Aluminum + tin cans = (0.87/5.48) x 15 = 2.4 yd3

ComponentsTotal solid wastelbsSpecific weightlbs/ft3Waste materials separatedLbsVolumeft3

Food Waste8.018.0

Paper35.85.6=35.8x0.8x0.2= 5.71.02

Cardboard6.43.15.11.65

Plastics6.94.15.51.34

Textiles1.84.1

Rubber0.48.1

Leather0.410.0

Yard Waste17.36.3

Wood1.814.8

Glass9.112.27.30.60

Tin cans5.85.64.60.82

Aluminum0.610.00.50.05

Other metals3.020.0

Dirt, Ash, etc2.730.0

Total100.005.48

Numbers of trip required to collect separate wasteAssume that waste generation= 3.82 lbs/capitaSolid waste production per home= 3.5 persons x 7 day/week x 3.82 lbs/capita.day= 93.6 lbs/week

Separated quantity of separated newspapers and cardboardsQuantity of newspapers in total production (home) = (5.7/100) x 93.6= 5.3 lbs/weekQuantity of cardboard in total production (home) = (5.1/100) x 93.6 = 4.8 lbs/week

Weekly volume of separated newspapers and cardboardSeparated newspapers = (5.3 lbs/week)/ (5.6 lb/ft3)= 0.946 ft3/weekSeparated cardboards = (4.8 lbs/week)/ (3.1 lb/ft3)= 1.54 ft3/week

Number of trips per week = [{(0.946 + 1.54) ft3/week .home} x 1200 homes x 0.6]/ (27 x 7.3)= 9.081= say 9 trips/week

Sheet1Collection vehicles Typical overall collection vehicle dimensionsTypeAvailable container or truck body capacities yd3No. of axlesWith indicated container or truck body capacity yd3Width inHeight mLength inUnloading methodHauled container systemHoist truck6-122109480-100110-150GravityTilt-frame12-503309680-90220-300GravityTrash-trailer15-403409690-150220-450GravityStationary container systemCompacter(mechanically loaded)Front loading20-4533096140-150240-290HydraulicSide loading10-3633096132-150220-260HydraulicRear loading10-3022096125-135210-230HydraulicCompacter(manually loaded)Side loading10-3733796132-150240-300HydraulicRear loading10-3022096125-135210-330Hydraulic

Sheet2

Sheet3