Recycle: A Computerized Planning Tool to Improve Municipal Solid

The Ohio State University

1986-12

Recycle: A Computerized Planning Tool to

Improve Municipal Solid Waste Management

Clapham, W. B., Jr. The Ohio Journal of Science. v86, n5 (December, 1986), 189-199http://hdl.handle.net/1811/23161

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Ohio Journal of Science (Ohio Academy of Science) Ohio Journal of Science: Volume 86, Issue 5 (December, 1986)

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Ohio J. Science AMMONIUM PRODUCTION BY B1P0LARIS MAYDIS 189

RECYCLE: A Computerized Planning Tool to Improve Municipal Solid WasteManagement1

W. B. CLAPHAM, J R . , Department of Geological Sciences, Cleveland State University, Cleveland, OH 44115

ABSTRACT. RECYCLE is a simulation model designed to assist municipal decision-makers in beginning theplanning process to determine what options in municipal recycling are appropriate for their communities. Itsstructure can be adapted to the vast array of municipal solid waste handling systems found around the country.It simulates a large number of options suitable for each type of municipal system and chooses the ones mostappropriate for community officials to examine in greater detail. It reflects the kinds of questions addressedin municipal solid waste management and is also appropriate for communities picking up their own refuse,contracting with specific private trash haulers, and having strictly private trash pickup. Model runs havealready influenced the structure of recycling programs in northeast Ohio, and the model has generated interestin several other areas.

OHIOJ. SCI. 86(4): 189-199, 1986

INTRODUCTIONSolid waste management is one of the largest items in

a municipal budget. An American family discards overtwo tons of refuse each year; a typical city of 50,000 canexpect to spend on the order of $2.5 million annually topick up, haul, and dispose of this refuse (CuyahogaCounty Regional Planning Commission 1980). About20-25% of this refuse is potentially recyclable (Table 1),indicating a significant possible savings for communitiesthat undertake serious recycling programs (Office of SolidWastes 1977). But every community is different. Recy-cling has so many site-specific aspects that it is neverobvious a priori what kind of program is most appropriatefor a particular city. Thus, a community will seldom beable to adopt a program identical to one that has workedfor a neighbor (Clapham 1983). In addition, some of themost important factors that enter municipal decision-making are "soft" variables like municipal image, natureof work rules with the service workers' union, personalpreferences of the municipal government, and so on.

RECYCLE is a generalized tool that clarifies the poten-tial roles for recycling in municipal solid waste (MSW)management programs and facilitates the early stages ofthe planning process. It allows planners to consider a vastrange of potential options for recycling without over-whelming them with vast amounts of information thatthey do not need to know about options which are in-feasible for the community. It provides a rapid, efficientmechanism for considering a broad range of possible op-tions in the context of individual communities and foridentifying a tractable number of feasible alternatives forfurther and detailed consideration. It is a fairly simplemodel whose assumptions and calculations can be verified

by planners normally inclined to distrust computer an-alyses. It can also provide sufficiently accurate informa-tion to be useful as a point of departure for detailedplanning.

STRUCTURE OF RECYCLE'The model is summarized mathematically in the ap-

pendix. It consists of several blocks that perform fourfunctions sequentially (Fig. 1). The first "describes" theMSW system of the community. It works interactivelywith the user to gain information about the site-specificfeatures of the city and then avails itself of other dataneeded to describe MSW management in more generalterms. Finally, it characterizes the potentially recyclablecomponents of the MSW stream.

The second block examines 24 different optionsin which the primary responsibility for recycling restson the shoulders of the householder. Twelve of theseare dropoff-donation centers (i.e., what are generally

TABLE 1

Makeup of typical municipal solid waste(MSW) in the United States, 1971-1975

'Manuscript received 25 November 1986 and in revised form20 June 1986 (#85-57).

Commodity

PaperGlassFerrous MetalsAluminumOther MetalsPlasticsRubber and LeatherTextilesWoodFood Wastes

Percentage

3 4 . 6 -12 .0 -10.2 -0 . 8 -0.44 . 2 -3 . 3 -1.7 -4 . 5 -

2 0 . 8 -

inMSW

43.013.310.8

1.0—

4.63.82.14.9

22.7

Ease of recyclingfrom MSW

HighHighHighHighLowLowLowLowLowNil

190 W. B. CLAPHAM, JR. Vol. 86

INPUT BLOCKInput Community DataRead Data Files

Tonnage of PotentiallyRecyclable Wastes

CENTERS BLOCKDescribe Operations of:* 12 Dropoff Centers* 12 Buyback Centers

End:Display of Best Options

Summary Report

For Each Option:Tonnages Recycled

Labor, Capital, & Space NeedsNet Savings

RANKING BLOCKPick Out Best OptionsSave Summary Data

PICKUP BLOCKDescribe Operations of:* 16 Curbside Collection Programs* 16 Pickup + Int. Processing Programs* 8 Licensee Pickup Programs

For Each Option:Tonnages Recycled

Labor, Capital, & Space NeedsNet Savings

FIGURE 1. Simplified flow chart showing functions of blocks within the recycling computer model.

termed "recycling centers"); the other 12 are buybackcenters in which recyclable materials are purchased fromhouseholders.

The third block considers 40 different configurationsof pickup programs in which primary responsibility re-mains with the city, and recycling is integrated into thesolid waste management program of the city. Sixteeninvolve simplified municipal pickup, in which the mu-nicipality collects the recyclables and sells them. Sixteeninvolve some "intermediate processing", in which themunicipality collects the materials and processes them tosome degree prior to sale to increase the sale value of therecyclable materials. The last eight options explore theimplications of the arrangement of a city with a non-profit licensee to collect recyclables independently of rou-tine municipal pickup.

The final block ranks the different options on the basisof the "bottom line," or net savings to the community,and picks from each of the five basic categories two thatpromise the greatest net savings to the community, andthat are most likely to be suitable for further consid-eration. Results presented to the user include net savingsfrom adopting a recycling program, as well as the consti-tutent costs and credits which make up this net saving.It then stores the basic data for all 64 options in a refer-ence file and prepares a summary report of 15 to 17 pagescontaining the implications of each of the options inlanguage that a municipal decision-maker can under-stand and work with.

BLOCK I: INPUT. The input block initializes themodel. It allows city-specific data to be entered into themodel, enables the user to change certain numerical dataso that they are more appropriate for his or her com-munity, and reads in basic parameters. After initializingthe model, it displays the assumptions used during themodel run, while the calculations and sorting operationsare being performed.

The block begins with an interactive section in whichthe computer asks the user for the community-specificinformation that adapts the structure of the model tolocal circumstances. The questions asked by the modelare summarized in Table 2. More details on the informa-tion required by the model are contained in the technicaldocumentation of the model (Clapham 1984a). In its

final step, the input block calculates the tonnage of theeasily recyclable commodities.

BLOCK II: CENTERS. The "centers" block analyzes24 typical options available at recycling or buyback

TABLE 2

Questions asked by the interactive section of RECYCLE

1. How many residents live in your municipality?2. What is the community's educational level?3. How many households do you collect refuse from?4. How many households are not collected (e.g. apartments)?5. How many tons of Municipal Solid Waste do you collect

annually?6. How many miles of city streets does your city have?7. How many daily routes does your city have for garbage pickup?8. What size crew do you use in garbage trucks in your muni-

cipality?9. What size garbage trucks, in cubic yards, do you use?

10. Are your garbage truck crews paid by the hour or by the route?11. Are there streets in your city along which garbage trucks must

routinely back up or turn around in extremely restricted areas?12. Do you use standard rear-loading garbage trucks?13. What is the composition of your municipal solid waste?14. What market prices are available for your recyclable

commodities?15. What is the typical HOURLY wage of your service workers?16. How many hours per week does a typical service worker work?17. Do you have a transfer station for municipal solid wastes?18. What is the average cost per ton of municipal solid waste pickup

and transport to your transfer station, if you have one, or directlyto your landfill, if you do not have a transfer station?

19- What is the average cost per ton of hauling minicipal solid wastesfrom your transfer station (if you have one) to your landfill?

20. What is the average tipping fee per ton for your refuse.21. Do you believe that you will be able to get facilities to store

recyclables in your recycling program free, either by donation orby agreement with your market? These include Gaylords, dump-sters, roll-off containers, etc.

22. Do you believe that you will be able to obtain free basic process-ing machinery to handle recyclables in a recycling center, eitherby donation or by agreement with your market?

23. Do you believe that you will be able to get free space to locatea recycling or buyback center?

24. Do you believe that you will be able to get free space to locatethe storage and transfer facilities needed for a curbside pickupprogram?

25. Do you believe that you will be able to get free space for trucksor trailers needed for certain options involving curbside pickup?These would likely be at your service center or transfer station.

26. Are you satisfied that all data you have entered are correct?

Start

Ohio J. Science RECYCLE: COMPUTER PLANNING MODEL 191

centers. It establishes a three-dimensional "optionsmatrix" defining the set of options available at differentkinds of centers. The dimensions are center types (i.e.,standard dropoff-donation or buyback center), hours ofcenter availability, and commodities accepted (Table 3).

This block first calculates the anticipated collections ofrecyclable wastes for each commodity collected via eachof the 24 options considered, based on total tonnage ofpotentially recyclable MSW and the appropriate par-ticipation rate. The participation rate is typically a func-tion of the educational level of the community (SCSEngineers 1974a, 1974b). The total tonnage recycled viaeach option is calculated by summing the collections ofall commodities. Sales for each commodity are deter-mined by multiplying the tonnage collected by its salevalue. For buyback centers, the model also calculates thepayout by the center to purchase recyclables. This isequal to the tonnage collected times the prices paid foreach commodity in a buyback center; these prices areassumed to be a proportion of the market value of eachcommodity. Total sales income and buyback expenses arecalculated by summing sales over all commodities foreach option within the matrix.

Next, the model calculates savings in MSW handlingcosts to the community in which centers are located.Recycled wastes do not have to be processed through theusual service functions of the community. The resultingsavings are credited to the calculated "income" stream ofthe recycling program. Collection expenses declineslightly, since service workers can complete their roundshaving spent less time picking up refuse. Likewise, recy-cled wastes never appear at the transfer station of themunicipality. They do not have to be loaded into special-ized packer trucks and hauled to a landfill; therefore, theydo not contribute to the wear and tear on the transferstation or its trucks. These expenses are reduced directlyin proportion to the amount of MSW removed from thewaste stream. Finally, recycled wastes do not have to belandfilled. The tipping fee that would have been paid todispose of the recycled wastes is credited to the incomestream as a savings.

Costs considered for recycling and buyback centersinclude capital, labor, and maintenance. Capital includesstorage facilities and machinery, and is proportional tothe tonnage collected. The annual costs of capital are

TABLE 3

Dimensions of the options matrix for centers

Type of Center

1. Recycling center (dropoff-donation)2. Buyback center (consumer is paid for recyclables)

Access to Center

1. Center is open all week (6 days per week, 8 hours per day)2. Center is open weekends only (2 days per week, hours per day)3. Center is open once per month (2 days per month, 10 hours per

day)

Commodities Handled by Center

1. Newspaper only2. Newspaper, mixed-color glass, mixed metals3. Newspaper, separated-color glass, separated metals4. Complex mixture of commodities

allocated to the balance sheet on a straight-line basis overan estimated lifetime. Labor and space needs are alsorelated to tonnage handled, subject to a minimum of oneworker and minimal space in order to allow the centerto function.

Finally, the model calculates net total income and thetotal costs of the center. Total income is equal to the sumof the savings in tipping, pickup, and hauling, as well asthe income from sales. The cost to the center is buybackexpenses incurred (if any), the depreciation of storage andmachinery, and the costs of labor and space. The netsavings due to the recycling program are equal to thegross income less the gross costs.

BLOCK III: PICKUP. The pickup block considersthose recycling options for which municipalities retainresponsibility for handling recyclable commodities byincorporating recycling into their municipal service pro-gram, whether by simple curbside pickup and immediatesale, curbside pickup followed by some intermediate pro-cessing, or by licensing pickup of recyclables to anotherparty. As with the centers block, the pickup block de-fines a three-dimensional options matrix (Table 4).

The operation of the pickup block parallels that of thecenters block. The model first calculates the anticipatedcollection of each commodity in each option in the ma-trix, based on the potentially recyclable tonnage andexpected participation rate. The tonnage of material di-verted from the waste stream via each option is thendetermined by summing over the range of commoditiescollected. Sales of materials are equal to the recyclablematerials actually collected times the sale value of thosematerials. Total sales for each option are calculated bysumming over all commodities.

Savings in pickup, hauling, and tipping are calculatedas in the centers block, except that no collection credit isgiven when truck-mounted racks or trailers are used. Inthese cases, all MSW that would normally have beenpicked up as refuse is picked up by the same crew on thesame truck, but separated into nonrecyclable and recy-clable components. Recycling systems using separate

TABLE 4

Dimensions of the options matrix for pickup program

Type of Pickup Program

1. Municipal curbside pickup without further processing2. Municipal curbside pickup with intermediate processing3. Curbside pickup by outside party licensed by municipality*

Technique of Pickup

1. Same truck as refuse pickup, using racks mounted on the trucks2. Same truck as refuse pickup, using trailers pulled behind trucks3. Different truck than refuse pickup, but collection on the same day4. Different truck than refuse pickup, with collection on different

day

Commodities Handled by Program

1. Newspaper only2. Newspaper, mixed glass and metals (i.e., collection as two com-

modities)3. Newspaper mixed with glass and metals (i.e., collection as one

commodity)4. Newspaper, mixed-color glass, mixed metals

*The third party licensee is limited, of course, to pickup optionsinvolving separate trucks different from those used by the muni-cipality for routine refuse pickup.


trucks are credited for collection savings by the refusetruck and then billed for the explicit cost of pickup by theseparate truck.

Capital costs are also handled as in the centers block,with the addition of equipment related to the actualpickup of recyclables. This includes racks or trailersmounted on existing garbage trucks or separate trucks forrecyclables pickup. For recycling systems using separatetrucks, the number of trucks required must first be cal-culated; this is done on the basis of street mileage inthe city, subject to a minimum of one truck. Recycledmaterials collected by municipalities are typically soldimmediately. However, some communities may wish tobeneficiate (e.g., separating paper from containers, glassfrom cans, aluminum from steel) materials to improvequality and market price. The capital costs of the equip-ment needed to do this "intermediate processing" arethen calculated, and the corresponding annual costsincluded in the figures for those options involving inter-mediate processing.

Labor and space needs are quite different from those ofthe centers block, since the structure of the recyclingsystems depends on whether existing labor and trucks areused. The marginal cost of both in pickup programsusing existing trucks is calculated by adjusting the basiclabor cost of operating and garaging a garbage truck. Thecost of pickup using separate trucks is based on theannual cost of operating one truck and the number oftrucks needed for the program. Space needs are propor-tional to tonnage recycled and include space for inter-mediate processing equipment and garaging additionaltrailers and trucks needed for the actual pickup, as wellas space to store materials.

Communities choosing to contract out recycling toanother agency will not bear most of the direct expensesincurred by communities that pick up recyclables sepa-rate from refuse. Nor will they receive the income fromsales. Their benefit is the reduction in costs of pickup,hauling, and tipping of recyclables diverted from thesolid waste stream. To assure those savings, communitiesneed to recognize that sales from recycling seldom coverthe entire cost of pickup and management. A licenseeassumes all of the costs of pickup and cannot use racks ortrailers on existing garbage trucks. In return, the licenseereceives only the income from commodity sales and doesnot benefit from savings in tipping fees or hauling costs.For this reason, cities using licensees will generally haveto provide some financial support; the question is howmuch. The model assumes that cities that benefit byhaving a licensee diverting MSW from their landfills willcontribute a portion of the tipping fee saved by therecycling program. In this way, they will continue tobenefit financially from recycling, and the licensee ismore likely to show a positive balance sheet.

Total income is, as before, equal to the savings fromtipping, pickup, and hauling, plus income from sales.Total costs include the costs of capital, labor, space, andany subsidies to non-profit licensees. Net savings is equalto gross income less gross costs.

BLOCK IV: RANKING AND DISPLAY. The rankingmodule ranks the various options on the basis of effective-ness. "Effectiveness" in this context can mean severaldifferent things. The most meaningful (and the one usedhere) is net savings to the solid waste management bill of

the community, although return on investment oramount of material recycled might also be appropriatecriteria for decision making. The function of the rankingblock is to cull the information derived by the previousmodules and present up to 10 different options so that theuser can understand what options are likely to be mostappropriate for the community.

Operations are ranked within the five types of pro-grams considered: recycling centers, buyback centers,curbside pickup without intermediate processing, curb-side pickup with intermediate processing, and pickup bya licensee. The two most effective options for each basic

Communi ty A

:

!!

!i!

j : ;

IDDC BC MCP CP+IP

C o m m u n i t y B

DDC

C o m m u n i t y C

MCP LP

•it

DDC MCP CP+IP LP

FIGURE 2. Graphic summary of the model runs for the three modelcommunities. Income and credits are shown in the left-hand columnfor each option; expenses and net savings to the community are shownin the right-hand column. The five options shown are the preferredoption in each of the five categories considered by the model:DCC, Dropoff/Donation Center; BC, Buyback Center;MCP, Municipal Curbside Pickup; CP + IP, Curbside Pickup plusIntermediate Processing by the Municipality; LP, Pickup of Recy-clables by Licensee.

Tho

usan

d D

olla

rsT

hous

and

D

olla

rs

Net Savings as Result of Recycling ProgramOther Expenses for Recycling ProgramExpenses for Additional LaborCredit for Disposal Fees AvoidedCredit for Pickup and Hauling Expenses AvoidedGross Income from Sales of Recyclables

Tho

usan

d D

olla

rs


category are chosen on the basis of net savings. The keyinformation from each option is displayed at the end ofthe model run. All 10 options and their associated netsavings are shown on the terminal (Fig. 2), enabling theuser to assess whether a different run should be madeimmediately to change some of the assumption used.This kind of "instantaneous feedback" may be a usefulway for carrying out the early stages of the planningprocess interactively with this type of model. At the sametime, this block prepares a report that includes all of thebasic data calculated by the model for each feasible optionchosen by the ranking block and corresponding descrip-tive text designed to assist the user in interpreting thecalculations.

VALIDATION AND USE OF THE MODELRECYCLE is a fairly simple model. It does not have

many decision boxes and does not attempt to simulate thedecision process. The calculations are simple, and theparameter values are fairly well understood. Its strategyis to allow its structure to be adapted to the vast array ofmunicipal solid waste handling systems found around thecountry, to simulate a large number of options suitablefor each type of municipal system, and to choose the onesmost appropriate for community officials to examine ingreater detail. Validation was done for several key optionswith figures from actual recycling programs. Enoughoptions need to be considered in the validation process sothat all different structures and all parameters are verifiedwith the experience of real communities. Several hundredcommunities around the United States have recyclingprograms that can be used to verify the structure andvalidate the numbers used. Justifications for the numbersare given in the detailed technical documentation pre-pared for the Office of Litter Control (Clapham 1984a).

An equally important sort of validation for a modelintended to have a role in the public policy process is itseffectiveness in assisting and improving decisions. Whenthe existence of RECYCLE was announced in the tradeliterature (Clapham 1985b), it generated considerableinterest. Copies of the program and its detailed documen-tation have been made available to individuals, consul-tants, and state or provincial solid waste authorities inover 12 states, four Canadian provinces, and the UnitedKingdom. Discussions with some of the people involvedsuggest that they have found the materials useful. It hasalready affected recycling programs in Cleveland Heightsand Lakewood, Ohio, in very different ways. Both citiesare inner-ring middle to upper-middle class suburbs thathave been willing to make a commitment to recycling.Cleveland Heights has had a city-operated newspaperrecycling program for several years, in which papers arepicked up by city service workers with racks mounted onstandard garbage trucks. An organization of citizens hasbeen pushing the city to expand this program to includeother materials as well; however, the city administrationhas been very resistant to change. The organization ofcitizens and the city both commissioned studies to assessthe suitability of different approaches to multi-materialpickup programs. Lakewood has long been interested inestablishing a recycling center, but had not done so untilfairly recently.

RECYCLE was applied to both cities. The analysis ofCleveland Heights demonstrated that the current news-

paper operation based on rack-mounted curbside pickupwas the second-best option within the municipal pickupcategory. The figures calculated by the model were essen-tially identical to actual data, so the credibility of themodel was quite high. The first choice was an expandedmulti-material pickup program similar in many ways tothat recommended by the consultant to the citizens'group. As expected, this latter option picked out by themodel had a substantially higher "bottom line." Never-theless, RECYCLE pointed out that the existing recy-cling program was the second choice, and that largersavings to the city promised by multi-material collectionentailed risks that the city was clearly unwilling to take.The group decided to delay pushing the city for changeuntil developments in the recycling market were clearer.

The City of Lakewood was interested in opening a verybasic recycling center accepting minimal materials fromthe public at some time in the future. The results fromRECYCLE convinced Lakewood that there was a marketfor glass at the current time. A glass recycling center wassubsequently established at the Lakewood transfer sta-tion. The experiences from this center were to be used toguide the city in any expanded recycling program. It hassince added newspaper recycling at the transfer stationand glass barrels at its fire stations.

RECYCLE has several characteristics that made it use-ful in these two cases. In Cleveland Heights, severalconsultants presented conflicting data and conclusions.The model was able to compare different approaches torecycling in a relatively straightforward and unbiasedway. Most importantly, it was able to compare the pro-posed multi-material pickup program with the existingprogram virtually on a point-by-point basis, so that thecitizens' group could clarify the benefits and the risks ofchanging the structure of the recycling program. It wassignificant (and unplanned) that RECYCLE picked outprecisely the existing program as a very viable secondchoice. Its role was very different in Lakewood. Here, itbrought together the basic data that needed to be consid-ered so that they were meaningful to the Litter Coordi-nator of Lakewood, and it provided some documentedalternatives that she could present to the Mayor.

MODEL OPERATION AND SAMPLE MODELRUNS

To see how the model works, consider three commu-nities. Community A is a suburb with a greater thanaverage educational level and a population of 50,000.Most of the data are taken from Cleveland Heights,Ohio. Community B is a district in a central city withaverage education and a population of 100,000. It isbased on the Old Brooklyn neighborhood of Cleveland,Ohio. Community C is a suburb with a less than averageeducational level and a population of 25,000. It is basedon East Cleveland, Ohio. Many other types of cities couldbe analyzed, but these three should provide insight intothe range of problems and opportunities facing real com-munities in the United States.

The three communities are assumed to have the samerefuse composition. The MSW consists of 10.4% news-paper, 7.5% glass, 4.0% steel, and 0.3% aluminum.This is the composition of MSW measured at the RidgeRoad transfer station in Cleveland, Ohio, and is a goodestimate for actual MSW composition for an urban area


TABLE 5

Market values of recycled communities assumed for sample model runs

Commodity Value (dollars per ton)

NewspaperColor-separated glassMixed-color glassSteelAluminumMixed cans (steel and aluminum)Mixed containers (cans and bottles)Mixed recyclables (containers and paper)

I 30.0035.0017.5012.00

800.0015.0013.0010.00

in the Great Lakes area in 1980 (Bechtel, Inc. 1980). Itwould be useful to have more precise data for commu-nities of different socioeconomic levels, since some otherkey variables are known to vary by economic or edu-cational level. The data are not available, however. Themarket values of the recyclable commodities used in theanalysis are given in Table 5. These numbers are averagevalues for the Cleveland area in the early 1980's. Likemost market values, these figures are subject to consid-erable fluctuation; they have been both considerablyhigher and lower. Other assumptions made for the modelruns are summarized in Table 6. City-specific assump-tions are derived from the communities for which themodel communities are patterned; other assumptions arejustified in the detailed documentation of the model(Clapham 1984b).

The results of the model runs are summarized inTable 7. Each column of numbers represents the optimaloption for communities A, B, and C, respectively, as

calculated by the model. The five parts of the table showresults for dropoff-donation centers, buyback centers,municipal curbside pickup, municipal curbside pickupwith intermediate processing, and licensee pickup,respectively. In addition to the net savings to thecommunity, the table documents the tonnage of re-cycled materials for each option, proceeds from sales,credits for expenses foregone, and costs for labor, space,and equipment.

The table emphasizes the tremendous benefits of scaleand the usefulness of a minimum community size foradequate support of a recycling program. Community C,with 25,000 residents, has l / 4 the population ofCommunity B. Yet its net savings in dropoff-donationprograms (i.e., the most popular approach) is 18% ofthat of community B. This is due to the lower edu-cational level (and hence to a lower likelihood of par-ticipating in a recycling program) of community C, aswell as the fact that the basic costs of a recycling oper-ation impinge disproportionately on a small programwhen compared to a larger program.

Buyback centers provide a different result. In this case,the net savings to community C are actually a little over25% of that of community B. The reason is that theopportunity to sell recyclables at a buyback center isrelatively more attractive in the poorer community. Italso raises the participation level to that of community C.

A similar case applies to recyclables picked up at curb-side. Community C has a net savings about 16% of thatof community B. As shown in Figure 2, the net savingsto the communities are much more parallel to the vol-umes of materials collected than are the savings fromrecycling centers. The most likely reason is that the labor

TABLE 6

Assumptions made in sample model runs

Assumptions

1. Residents2. Educational Level3. Annual MSW collection (tons)4. Miles of city streets5. Number of daily garbage

truck routes6. Workers on garbage truck crews7. Crews paid by hour or route8. Size of garbage trucks (yards)9. Hourly wage of service workers

10. Side-load or rear-load trucksused for garbage pickup

Assumptions Specific

Community A

50,000Above avg.

25,000125

71

Route12

$10.00

Side

Assumptions Common to

11. Street patterns allow use of trailers if appropriate.12. Work week for service workers is 40 hours.13- All communities have a transfer station.14. Pickup cost of refuse per ton is $70.00.15. Hauling cost of refuse per ton is $20.0016. Tipping fee for refuse per ton is $10.00.17. Storage containers are free for recycling centers.18. Basic processing machinery for centers is available free.19- Space for recycling centers must be rented.20. Space needs for pickup programs is free.21. Space for garaging trucks and trailers is free.

to Communities

Community B

100,000Avg.45,000

275

93

Hour20

$10.00

Rear

All Communities

Community C

25,000Below avg.

12,00075

53

Hour16

$9.00

Rear


TABLE 7

Summary of income and expense streams (in dollars) from most feasible option for each type of recycling mode, based on model runs

Community

Dropoff-Donation Center

(All centers are geared for multi-material intake.)

A B

Scale of operationTonnage collectedSales of recyclablesCredit for reduced pickup expensesCredit for hauling expenses avoidedCredit for tipping expenses avoided

Gross income from sales and creditsNumber of workers (FTE)Labor costs for the center

Gross costsNet saving to community

Daily762.1

29,161.695,334.66

15,241.887,620.94

57,359.171.8

16,918.4816,918.4840,440.69

Buyback Center

Daily1,207.2

46,192.128,450.10

24,143.1312,071.5790,856.92

2.926,789.8826,789.0864,058.04

Weekends219.5

8,398.571,536.384,389.662,194.83

16,519.441.6

4,872.524,872.52

11,646.92

Community

(All centers are geared for multi-material intake, daily operation.)

A B C

Tonnage collectedSales of recyclablesCredit for reduced pickup expensesCredit for hauling expenses avoidedCredit for tipping expenses avoided

Gross income from sales and creditsNumber of workers (FTE)Labor costs for the centerPayouts for buyback of materials


1,270.248,602.818,891-09

25,403.1312,701.5695,598.59

3.128,197.4724,301.4152,498.8843,099.71

2,172.083,110.8115,203.7743,439.3421,719.67

163,473.595.2

48,217.6741,555.4189,773.0873,700.51

560.921,463.00

3,926.3111,218.025,609.01

42,216.341.3

12,452.0010,731.5023,183.5019,032.84

Community

Municipal Curbside Pickup

(All programs collect two commodities: paper and mixed containers.)

A B C

Type of operationTonnage collectedSales of recyclablesCredit for reduced pickup expensesCredit for hauling expenses avoidedCredit for tipping expenses avoided

Gross income from sales and creditsAnnualized cost of equipmentAdditional labor costs


Racks2,132.8

46,732.400.00

42,656.0021,328.00

110,716.40600.00

10,429.0011,029.0099,687.40

Trailers3,455.1

75,706.480.00

69,102.7234,551.36

179,360.561,800.00

10,429.0012,229.00

167,131.56

Trailers819.0

17,945.250.00

16,379.908,189.95

42,515.101,000.009,386.10

10,386.1032,129.00

Community

Municipal Curbside Pickup Plus Intermediate Processing


A B C

Type of operationTonnage collectedSales of recyclablesCredit for reduced pickup expensesCredit for hauling expenses avoidedCredit for tipping expenses avoided

Gross income from sales and creditsAnnualized cost of equipmentAdditional labor costs


Racks2,132.8

75,239.250.00

42,656.0021,328.00

139,223.253,406.86

28,366.2431,773.10

107,450.15

Trailers3,455.1

121,887.600.00

69,102.7234,551.36

225,541.686,735.91

45,953.3152,689.22

172,852.46

Trailers819.0

28,891.880.00

16,379.908,189.95

53,461.732,170.009,803.37

11,973.3741,488.36


TABLE 7 (continued)

Community

Recyclables Pickup Licensed to Outside Contractor


A B C

Tonnage collectedSales of recyclablesCredit for reduced pickup expensesCredit for haulinge expenses avoidedCredit for tipping expenses avoided

Gross income from sales and creditsDirect subsidy to contractor

Gross CostsNet saving to community

1,984.00.00

13,888.0039,680.0019,840.0073,408.0015,872.0015,872.0057,536.00

3,214.10.00

22,498.5664,281.6032,140.80

118,920.9625,712.6425,712.6493,208.32

716.90.00

5,332.9915,237.127,618.56

28,188.676,094.856,094.85

22,093.82

supply for curbside pickup is already working for thecommunity in its service department or in the sanitationcrews of its refuse contractor. The level of recycling withan active pickup program is also typically aboutthree times that of a dropoff-donation program. When itis easy for people to recycle, they will do so.

The model also has been used to investigate the impactof a bottle bill on recycling programs, specifically todetermine the degree to which beverage container depositlegislation is "parasitic" on active recycling programs(Clapham 1985a). The results of this study demonstratethat deposit legislation does not reduce the net benefit ofrecycling programs. Indeed, it is unlikely to cause severedamage to a recycling program with an adequate resourcebase, since the economic base of most recycling programsis newspapers rather than beverage containers. The over-all benefit to a community carrying out an active recy-cling program is increased substantially by beverage con-tainer deposit legislation, owing to the greatly increasedparticipation level that characterizes communities withdeposit legislation. The two approaches to recyclingcomplement each other quite well and should be viewedas compatible tools for maximizing the results of ex-penditures for municipal solid waste management and forimproving litter control.

SYSTEM REQUIREMENTSRECYCLE has been implemented on an IBM Personal

Computer in Microsoft Pascal. It requires 192 Kbytes ofmemory to run. It uses 174 Kbytes of disk space to storethe model and its associated data files and an additional34 Kbytes of disk space for files written during a run. Inaddition, RECYCLE requires WordStar and its Mail-Merge option to print the report from a summary filewritten by the model. Thus, the total disk space require-ment for RECYCLE and all ancillary files is somewhatless than a single floppy disk on the IBM Personal Com-puter . A typical working session takes aboutfive minutes.

OBTAINING AND USING RECYCLE'RECYCLE is in the public domain and can be used by

anyone. A complete listing is provided in the documen-tation prepared for the Office of Litter Control, OhioDepartment of Natural Resources (Clapham 1984a,1984b). Readers of this article may obtain a copy of thisdocumentation or a disk containing the model at cost, or

they may arrange to run the model for their communityat their convenience. Interested parties should contactthis author.ACKNOWLEDGMENTS. This model was prepared as part of a researchproject sponsored by the Office of Litter Control, Ohio Departmentof Natural Resources. I would like to thank Ann Crowner of thatoffice for her support and interest throughout this project.

LITERATURE CITEDBechtel, Inc. 1980 Solid Waste Resource Recovery Facility,

Phase II Report. Cleveland: Cuyahoga County Commissioners, Of-fice of the Sanitary Engineer.

Clapham, W. B., Jr. 1983 Recycling and Solid Waste Manage-ment. Resource Paper for Northeastern Ohio Litter and RecyclingSeminar. Columbus: Cooperative Extension Service.

1984a Introduction to the Recycling Computer Model.Prepared for the Office of Litter Control, Ohio Department ofNatural Resources. Available from Department of Geology, Cleve-land State University.

1984b How to Use the Recycling Computer Model. Pre-pared for the Office of Litter Control, Ohio Department of NaturalResources. Available from Department of Geology, Cleveland StateUniversity.

1985a An analysis of the potential effect of beverage con-tainer deposit legislation on municipal recycling programs. J. Env.Systems 14: 241-267.

1985b Computer model helps communities identify recy-cling programs. Resource Recycling March/April 1985: 24-25,36.

Cuyahoga County Regional Planning Commission 1980 SolidWaste Management Report: Final Draft, Phase 1. Cleveland,Cuyahoga County Regional Planning Commission.

Office of Solid Wastes, United States Environmental ProtectionAgency 1977 Fourth Report to Congress: Resource Recoveryand Waste Reduction. Washington: U.S. EPA Publica-tion SW-600.

SCS Engineers 1974a Analysis of Source Separate Collection ofRecyclable Solid Waste — Separate Collection Studies. Washing-ton: U.S. EPA EPA/53O/SW95cl.

1974b Analysis of Source Separate Collection of Recy-clable Solid Waste — Collection Center Studies. Washington: U.S.EPA EPA/53O/SW95c2.

APPENDIX: Mathematical Summary of the ModelBlock I: Input

PTRC — Proportion of recyclable materials in MSWcollectionsTRC — Total tonnage of potentially recyclable MSWTSWC — Total solid waste collections

TRQ = PTRQ * TSWC ,

where /' refers to newspaper, glass, ferrous metals, andaluminum.


Block II: CentersAmounts

CRW — Anticipated collection of recyclable wastes bycommodityPR — Participation rateTC — Total tonnage of collections for each optionTRC — Total tonnage of potentially recyclable MSW

where i is as before and o refers to the particular optionunder consideration.

Sales and Buyback Income and ExpensesBCRW — Total payout for purchase of recyclables in abuyback centerBV — Price paid for each commodity in a buyback centerCRW — Anticipated collection of recyclable wastes bycommodityPMV — Buyback payout price as proportion of the salevalue of each commoditySCRW — Gross income from sales of each commoditySV — Sale value, by commodityTSI—Total income from sales of recyclablesTBE — Total buyback expenditures

Credits

CH — Credit for savings in hauling from the transferstation to landfillCHPT — Cost per ton for hauling refuse from transferstation to landfillCP — Credit for cost reduction in neighborhood pickupCPPT — Cost per ton for refuse pickupCT — Credit for savings in tipping (i.e. disposal) ofwastesCTPT — Cost per ton for tipping wastes at the landfillGI — Gross incomeTC — Total tonnage of collections for each optionTSI — Total income from sales of recyclables

LC —Total labor cost to the programMW — Minimum wageRS — Requirements for spaceRW — Requirements for workersSC — Annual cost of space for recycling centerSLD — Straight-line depreciation on capital,SRNT — Space rental per unit areaTBE — Total buyback expendituresWY — Workyear in hours per year

Net SavingsGC — Gross costsGI — Gross incomeNET — Net savings from the center

Block III: PickupAmounts

CRW — Anticipated collection of recyclable wastes bycommodityPR — Participation rateTC — Total tonnage of collections for each optionTRC — Total tonnage of potentially recyclable MSW

where i and o are as in the previous block.Sales Income

CRW — Anticipated collection of recyclable wastes bycommoditySCRW — Gross income from sales of each commoditySV — Sale value, by commodityTSI — Total income from sales of recyclables

CostsCC — Capital costsELC — Estimated lifetime of capital of recyclingprogramGC — Gross costs

CreditsCH — Credit for savings in hauling from the transferstation to landfillCHPT —Cost per ton for hauling refuse from transferstation to landfillCP — Credit for cost reduction in neighborhood pickupCPPT — Cost per ton for refuse pickupCT — Credit for savings in tipping (i.e. disposal) ofwastesCTPT — Cost per ton for tipping wastes at the landfillGI — Gross income


TC — Total tonnage of collections for each optionTSI — Total income from sales of recyclables

CP0 = 0.0 for rack and trailer-based systems;

otherwise CP0 = TC0 * CPPT * 0.1.

CH0 = TQ * CHPT if there is a transfer station:

otherwise CHfl = 0.0.

Costs

AME —Base annual truck maintenance expenseAVN — Average velocity (truck mi/hr) needed to servicethe entire communityAVF —Average velocity possible for a real "cruising"recycling truckAW — Average annual wage paid to sanitation workersCCI —Capi ta l costs for intermediate processingequipmentCCS — Capital costs for storageCCP — Capital related to the actual pickup of recyclablesCG — Per-gallon cost of gasolineCRT — Per-truck cost of racks or trailersCT — Credit for savings in tipping (i.e. disposal) ofwastesCTR — Price of a truck used for separate recyclablespickupDC — Dropoff costELCI — Life expectancies of capital invested in inter-mediate processingELCP — Life expectancies of capital invested in pickupELCS — Life expectancies of capital invested in storageGAS — Gasoline costsGC — Gross costsGT — Number of garbage trucks used in standard MSWpickupLTF — Daily cost of dropping off materials at recyclingtransfer facilityMLC — Marginal labor costs of the recycling operationMPG —Truck's gas consumption in miles per gallonMT — Number of miles to be travelled each weekPTF — Proportion of the tipping fee saved by recyclinggranted as subsidyRS — Requirements for spaceRSC —Basic refuse service costRTR — Number of trucks required for separate-truckrecycling programsRW — Requirements for workersSC —Annual cost of space for storing recyclablesSCE — Cost of space for equipment storageSENT — Cost of space per unit area in equipment storageareaSLD — Total straight-line depreciation on capitalSLDI — Straight-line depreciation on investment inintermediate processingSLDP — Straight-line depreciation on investment inpickup equipmentSLDS — Straight-line depreciation on investment instorage facilitiesSRE — Additional space needed to store equipmentinvolved with collection

SRNT — Space rental per unit area in recyclables storageareaST — Storage requirements per trailerSTK — Storage space needed per truckSUP — Financial support for licensee pickup ofrecyclablesTC — Total tonnage of collections for each optionTCS — Crew size of each truckTOM — Truck operating and maintenance costsTS— Time surcharge to load recyclables into trailers onside-loading trucksTSM — Community's total street mileageWDY — Number of workdays in a yearWW — Working hours in a weekWS — Wage surcharge

For systems based on all methods of pickup

if pickup is licensed to third party;

otherwise SOP9 = 0.0.

For systems based on racks and trailers

if community has no transfer station;

otherwise DC0 = 0.0

WSfl — 0.0 if crews are paid by the route;

otherwise WS0 = 0.02

For rack-based systems

For trailer-based systems

TS0 = 0.0 if garbage trucks load from the rear;

otherwise TS0 = 0.02

For systems based on separate trucks


GAS, = MX * 52 * CG/MPG

TOM0 = GAS0 + (AME0 * RTRj

MLQ = RTR0 * AW

SRE0 = RTR0 * STK

For systems based on all methods of pickup

CCI0 a TC0 for systems with intermediate processing;

otherwise CCI0 = 0.0

SLDS0 = CCS./ELCS

SLDPfl = CCP0/ELCP

SLDI0 = CCI0/ELCI

SLDn = SLDS0 +• SLDPB + SLDI0

SCE0 = SRE0 * SENT

G Q = TOM0 + SLD0 + MLQ

+ SCE,, + DC0 + SUP0

GC -Gross costs-Gross income

Net Savings

SCe

GI — Gross income

NET — Net savings from the center

NET0 = GI0 - GC0

Block IV: Ranking

NET, = max (NET0) ,where o is as before and c refers to the options chosen.The term max refers to the two maximum values for eachtype of operation.

Documents

Recycle: A Computerized Planning Tool to Improve Municipal Solid