Now that a context of industrial considerations and the projected supply in Berkeley has been set, finances and collection mechanics can be considered. Adding plastic containers to the curbside collection program in Berkeley would necessarily add costs in operations and in other areas, including a public education program to tell residents about the change. Operational costs may be incurred for new collection equipment, expanding processing facilities and storage capacity, added labor, and other increased operating expenses.

Possible benefits could include income, diverting more material from landfill, conserving more resources and energy, providing an opportunity for local economic development, and increasing customer service and satisfaction.

The balance of costs and benefits is the subject of the following analysis, which examines the question of beginning curbside recycling collection of plastic bottles made of PET (soda and custom), and natural HDPE (milk and water jugs) in Berkeley.

Estimated amounts available for collection in Berkeley

To assess costs and benefits, we must project how much material curbside collection could divert from landfill. As previously noted, research conducted for a 1991 study showed that Berkeley landfilled more than 650 tons of PET and HDPE. This figure provides only a point of reference because plastic packaging use and disposal has increased significantly since 1991. Also, the study gives no information on the sources of the material or the types of articles included in the categories. For example, the common five-gallon plastic pail used for commercial quantities of food and construction products would be included in the composition study as HDPE, but is not a target material in this analysis.

To respond to the Berkeley City Council’s January 1995 request for a plastics recycling plan, staff of the City’s Refuse and Recycling Division, the Ecology Center, and Community Conservation Centers developed estimates of the quantities of plastic bottles that could be collected for recycling. The organizations used several sources of information, including a 1995 report from the American Plastic Council, the Plastics Recycling Plan for San Diego County, and information from other cities. The tonnage projections the three groups developed varied only slightly and can be fairly represented as follows:

Table 4: First Estimate of Plastic Bottles Available in Berkeley

Program PET (tons/year) HDPE (tons/yr.)
Dropoff 6 32
BuyBack 12  
Curbside 26 134
Commercial 6 34
Totals 50 200

The estimated quantity of plastic bottles that could reasonably be captured for reprocessing represents less than one-half of 1% of the municipal waste stream.

How we projected the costs of adding plastic containers to the curbside program

The costs for adding any material to the recycling system in Berkeley should be considered in terms of both incremental and allocated costs. Incremental costs are all the extra expenses necessary to collect, process, and market the new material. Examples of incremental costs are special equipment such as compactors, additional collection trucks and crews, new educational materials, and publicity. Analyzing incremental costs is helpful in deciding what the budgetary effect will be of adding a new material to the collection service.

Allocated costs are the ongoing operational costs of collection, sorting, baling, etc., assigned to each material handled by the program. Allocated costs are usually expressed in dollars per ton, even though allocations may be based on various complicated factors such as time required for collection or percent of volume occupied in the collection truck. Allocated-cost analysis provides a basis for comparing the costs of collecting plastic containers with the costs of collecting other materials.

The difference between incremental and allocated costs can be illustrated this way: if adding a material requires buying a new baler and adding one person to the payroll, the purchase and added staff are incremental costs. But when the baler is up and running, if it processes three existing materials in addition to the new one, allocating the costs would divide the operating costs among both new and existing materials according to how much cost they incurred in baler time and maintenance. Similarly, adding a new staff person may be an incremental cost. But once he or she is on the payroll, the total staffing costs can be allocated among the new and existing materials according to the labor they require.

Incremental and allocated costs of adding plastic bottles to Berkeley recycling programs

Community Conservation Centers (CCC) accepts PET and natural HDPE bottles at both its recycling centers and purchases California redemption value PET at The BuyBack. Although some capital costs must be incurred to increase storage capacity and security, CCC found that market prices in early 1995 were high enough to cover the costs of processing and marketing the bottles.

The City of Berkeley’s commercial collection program has been collecting plastic bottles from 45 bars and restaurants for several months. The program collects several hundred pounds of plastic each week, mostly HDPE. (Note: most of this report calculates materials in tons, not pounds.) In 1995 City staff estimated that the only additional cost to add plastics to all commercial collection accounts would be one-half fulltime-equivalent (FTE) collection worker. City staff has recently revised estimated tonnage from the commercial program to include service to 9,000 apartment households in large buildings, more than a hundred food service establishments, and 500 other buildings. Estimates for the expanded program are 21 tons of PET and 50 tons of HDPE annually.

Processing costs must also be considered. CCC processes materials from the City and the Ecology Center, and to expand commercial collection or begin residential curbside collection of plastic bottles, CCC’s current sorting system for glass and cans must be improved. CCC estimates the capital costs for these improvements at $64,100. CCC also estimates that one additional sorter will be needed to sort the tonnage projected for both the commercial and curbside programs. Additional costs must be also be considered for handling, perhaps baling, and transporting bales or unbaled containers to local buyers. CCC has estimated the incremental costs for adding sorting personnel, baling time and supplies, shipping, and overhead to be more than $200 per ton. The estimate was based on sorting 194 tons annually of two types of plastic from loads of mixed bottles and cans.

Accurately forecasting the volume of plastic expected to be set out for collection is critically important for the curbside collection program. Enough truck capacity must be provided to handle the new material as well as the increase in participation that normally occurs after a fresh public education program. The anticipated weight and volume depend on a number of factors such as the market share of plastic compared to other container types, whether they have deposit or redemption value, and demographic profiles of the neighborhoods served.

The American Plastics Council (APC) conducted extensive research on plastic-bottle recycling from 1992 to 1994 and published their results in a 1995 report, How to Collect Plastic for Recycling. The APC studied curbside and dropoff programs across the country and collected extensive data on how many plastic bottles were available and set out for recycling. Three of the programs studied were in states with beverage container redemption or deposit legislation (“bottle-bill” states): San Francisco, California; West Linn, Oregon; and Springfield, Massachusetts. This report will use the results from San Francisco and the average for the three bottle-bill states to model a collection program for Berkeley.

The APC study found the following “generation rates,” which include amounts found in household recycling bins and garbage cans but exclude bottles discarded away from home or taken to recycling or redemption centers.

Table 5: Plastic Bottle Generation Rates

San Francisco
Bottle Bill
PET soda 1.3 1.1
PET custom 2.8 2.4
Total PET 4.1 3.5
Natural HDPE* 5.7 12.6
9.8 16.1

*Milk and soda jugs.

San Francisco had significantly less natural HDPE than any other city in the study. The APC suggests that this might be due to the nature of the sampled routes, and that perhaps fewer families had small children.

A rough estimate of the tonnage available for collection can be obtained by applying the following calculation:

tonnage available = (the number of households served by the program) x (the generation rate in lbs/yr) x (the participation rate) x (the capture rate) / (2000 lbs/ton).

The participation rate is the percentage of households that participate in the program at least once a month. The capture rate is the percentage of the materials that are actually set out for curbside recycling and not tossed in the trash or taken to a recycling center. Of course, generation, participation, and capture rates vary due to a great number of factors including family size, education and promotion campaigns, and collection methods.

The APC study recorded an average participation rate of 71% in the six study programs, and capture rates for HDPE and PET were about 65%. The Ecology Center’s curbside recycling program serves about 35,000 households residing in single-family and multi-family buildings up to nine units. Using the generation and participation rates found by the APC study, the calculations are:

San Francisco used as basis
(35,000 households) x (9.8 lbs/yr) x (71% participation) x (65% capture) / 2000 lbs/ton = 79 tons/year capturable in Berkeley

Bottle Bill States Average used as basis
(35,000 households) x (16 lbs/yr) x (71% participation) x (65% capture) / 2000 lbs/ton = 129 tons/year capturable in Berkeley

These calculations can be further refined by using the capture rates for each bottle type. These are: 48% for custom PET, 60% for soda PET, and 70% for natural HDPE. The resulting tonnages are shown in the following chart:

Table 6: Second Estimate of Plastic Bottles Capturable in Berkeley

Basis: San
Basis: Bottle
Bill States Average
PET soda 9.7 8.2
PET custom 16.7 14.3
Total PET 26.4 22.5
Natural HDPE* 49.6 109.6
76.0 132.1

The PET tonnage is lower than the estimate of 50 tons made in 1995 by the Ecology Center, CCC, and City staff. The HDPE tonnage is considerably lower than the 200 annual tons first estimated. Until a better estimate is available, the bottle-bill states’ average of 132.1 tons will be assumed to approximate the tonnage of plastic bottles available for collection in Berkeley.

To gain a fuller understanding for good program planning, however, we need not just an average tonnage, but an anticipated range for both tonnage and volume. For reference, we will set the anticipated HDPE tonnage range at a low of 76 tons per year and a high of 160, with an average of 132. Now the volume of the materials must be found.

The APC study found the average density of materials set out for curbside collection to be 32 pounds per cubic yard for PET (soda and custom) and 20 pounds per cubic yard for natural HDPE. For the anticipated annual tonnage, the collection program would be expected to pick up a low of 25.5 cubic yards, a high of 58 cubic yards, and an average of 47 cubic yards every day, five days a week, 52 weeks per year.

The APC uses another method to calculate truck requirements for bottles and cans. It recommends using data they collected on average set-out volumes and set-out rates. This method results in somewhat higher capacity requirements but is perhaps more accurate since it is derived by measuring actual set-outs in the study areas.

The APC’s data reflects an assumed set-out rate of 48% and 1,000 households per route. In Berkeley, an average of 7,000 households are served per day. With those assumptions, the APC’s calculation can be applied to Berkeley with the following results:

Table 7: Average Daily Volume Capturable in Berkeley Using APC Assumptions

Material Average
Daily Volume
  Cu. yds/route
(1,000 households)
Cu. yds/ day
(7,000 households)
Cans 4.6 32.2
Glass 5.6 39.2
Plastic 8.2 57.4
Total 18.4 128.8

Therefore, average daily volume can be estimated at 129 cubic yards per day for all container types, with plastic bottles accounting for 57.4 cubic yards per day.

The Ecology Center has five high-capacity trucks, each with a capacity of 30 – 35 cubic yards; two 1990 bin trucks at 17 cubic yards; and two older bin trucks for backup. The seven trucks in regular use have a combined capacity for glass and cans of just over 60 cubic yards. Thus, if each truck could make two full trips every day and every route were average, only a few yards of extra capacity would be required and could probably be accommodated with the backup trucks. This calculation also assumes that plastic could be collected commingled with both cans and glass. Commingling adds processing costs but avoids the additional costs associated with supplying and collecting an additional curbside tote box.

In Berkeley, demographics, terrain, and the existing refuse collection days require curbside recycling collection routes that vary widely from the statistical average. The routes with highest participation are often the least efficient to collect because they are far from the recycling yard, the stops are far apart, and narrow and dead-end streets require extra time for maneuvering. Therefore, it is not always possible to collect two full trucks in an eight-hour shift from routes on the eastern side of Berkeley. Also, in high-participation areas, one route cannot serve a thousand houses per day, so more and smaller routes are necessary.

Replacing the two bin trucks with high-capacity trucks would add about 9 cubic yards for glass, cans, and plastics (increasing capacity to 70 cubic yards ) without requiring additional staff. If the bin trucks were also used on heavy days, total capacity would be over 80 cubic yards for one trip, with an additional 40 – 50 cubic yards available for second trips and the remaining 30 – 40 cubic yards available for overtime collection on heavy days.

One option is to add plastic compactors to all seven trucks to increase collection capacity. The APC study did extensive testing of several different makes and models of on-board compactors. They increase loading time on the route but also increase collection capacity somewhat. Overall, however, the study found on-board compaction to be of marginal use in bottle-bill states using commingled collection. Adding compactors in the space behind the cab of the Lodal trucks (two bin trucks and three high-capacity trucks) and under the frame of the other two high-capacity trucks might provide necessary overflow capacity to prevent the container compartments from filling up before the paper sections. This installation would require the collectors to manually sort plastic at the curb, adding considerable time to the collection.

Also, all the compactors tested in the APC study had features that made them either inconvenient or difficult to load and unload. One of the test routes, in West Linn, Oregon, used a compactor for commingled cans and plastic. The test showed that there was no problem with interlocking the materials, which could be routinely processed at the sorting facility. The particular compactor tested in the study is too small to be of use on the Ecology Center’s trucks, but the idea might be expanded into something useful locally. If a compactor could be fed from the overhead troughs and fitted to use the entire can compartment for storage of compacted cans and plastic, collection capacity would be added with very little increase in collection time.

Clearly, the alternatives for collection should be analyzed before investment is made in new equipment. However, a range of costs can be determined for the scenarios suggested above.

  1. Overflow compactors for plastic only, 7 trucks $ 70,000
  2. Overflow (2) and commingled (5) compactors 95,000
  3. One new collection truck 130,000
  4. One new truck, commingled compactors 6 trucks 220,000
  5. One new truck, commingled (6) and overflow (2) compactors 240,000
  6. Two new collection trucks 260,000
  7. Two new trucks, commingled compactors 7 trucks 365,000
  8. Two new trucks, commingled (7) and overflow (2) compactors 385,000

Additional routes would have to be added and more trips made, so there would be an increase in labor and operating expenses, such as fuel and maintenance. Test or pilot routes could be done in various areas of the City to provide data on participation, collection time, and volumes. These data could be used to predict closely the additional operating costs necessary to add plastic bottles to the curbside collection program. In the absence of real data, an example can be modeled on the APC study and knowledge of the local conditions and program.

We have calculated incremental operating costs for adding plastic bottles based on the following assumptions:

  1. Three new routes are required, an increase of 10%.
  2. All routes require two or three trips, for a total of 70 trips per week, an increase of 30%.
  3. An average of 0.6 extra hours per route would needed to collect plastic; half of this increase can be accommodated in the regular shifts, and half results in overtime.

Those assumptions would add these approximate additional costs:

  1. Three driver-days per week = .6 full-time equivalent driver $23,000
  2. Thirty percent increase in fuel and maintenance costs 8,500
  3. Overtime pay for 0.6 hours @ half of 33 routes /week
    @ 1.3 crew per route 14,270

Estimated Annual Incremental Operating Expenses: $45,770

These figures are indicative but not complete. Other factors may increase or decrease incremental expenses. For example, adding a new truck would increase insurance expense, while replacing the bin trucks would eliminate the cost for forklift operation, fuel, and maintenance. A potential savings from re-routing might be used to offset some of the additional operating costs.

Projected revenues

Market prices for plastic bottles in 1996 have dropped dramatically from the high experienced during 1995. In California, however, PET prices are subsidized by the plastics industry and should therefore remain high as long as container redemption legislation is in effect. The following table indicates the revenue expected at today’s market prices.

Table 8: Annual Revenue Expected from Sale of Collected PET and HDPE

Program PET tons Sales PET crv* HDPE tons Sales Total
Dropoff 6 $4,620 $2,520 32 $4,480 38 $11,620
BuyBack 12 $9,240       12 $9,240
Curbside 23 $17,710 $7,820 110 $15,400 133 $40,930
Commercial 21 $16,170 $6,720 50 $7,000 71 $29,890
TOTALS 62 $47,740 $17,060 192 $26,880 254 $91,680

*California redemption value; not included for BuyBack since it is paid to customers.

Summary of costs for adding plastic bottles to Berkeley recycling programs

Adding plastic bottles to the recycling system in Berkeley could be done through some or all of the existing programs. PET and HDPE are already accepted at the dropoffs, and the BuyBack began purchasing PET on April 2, 1996. The cost for these additions is expected to be covered by the revenue from sales. Advertising the program would boost tonnage.

Adding plastic bottles to the residential curbside and commercial collection programs would increase the tonnage collected, but at a net cost per ton. To make the addition, the sorting system must be expanded to process plastic commingled with other containers from either the curbside or commercial programs. So it would make economic sense to add plastics to both household and commercial programs if the expansion is done.

Table 9 shows the costs and revenues for adding plastic bottles to both the commercial and curbside programs. The table includes revenue from 71 tons from commercial collection and 133 from curbside collection. The costs include a good public education program and capital costs from scenario 5 above. The net incremental cost for this scenario is $826 per ton averaged over the first four years of the program.

If the other capital-cost scenarios are substituted in the table, a range of net costs may be obtained. The low end of the range would be $580 per ton for scenario #1 and the high would be $1,033 for scenario #8.

Table 9: Summary of Costs for Adding Plastic Bottles to Commercial and Curbside Collection in Berkeley

1st Year 2nd Year 3rd Year 4th Year Total
Processing Equipment $64,100       $64,100
Commercial Collection

Public education

10,000 10,000 10,000 10,000 40,000
0.5 FTE collector 27,710 27,710 27,710 27,710 110,840
Processing costs
@ $250/ton
17,750 17,750 17,750 17,750 71,000

Curbside Collection

Public education

40,000 20,000 20,000 20,000 100,000
One truck and compactors
($240,000 loan with interest @ 40 months)
84,444 84,444 84,444 28,148 281,480
Operating costs 45,700 45,700 45,700 45,700 183,080
Processing costs @ $200/ton 26,600 26,600 26,600 26,600 106,400
Total Incremental Costs $316,374 $232,274 $232,274 $175,978 $956,900



29,890 29,890 29,890 29,890 119,560
Curbside 40,930 40,930 40,930 40,930 163,720
Total Revenues $70,820 $70,820 $70,820 $70,820 $283,280
Net Incremental Cost $245,554 $161,454 $161,454 $105,158 $673,620
Net Cost per Ton $1,204 $791 $791 $515 $826

Links between plastic reprocessing and landfilling

The calculations above assume that curbside collection would have no impact on plastic packaging use. However, it is likely that establishing plastics collection would increase consumption by making plastic appear more ecologically friendly both to consumers and retailers. By making plastics seem ecologically friendly, collecting plastics at curbside would legitimize the production and marketing of packaging made from virgin plastic. But much of this packaging is in fact unrecyclable, so the effect could be a net increase in the amount of plastic discarded, collected as garbage at City expense, and sent to the landfill.

This is our reasoning: curbside collection would divert only about 8.4% of the available discarded plastic from waste, so even a small increase in plastic packaging sales would increase the plastic landfilled. If consumption of plastic packaging (all resin types) increased by only 9.2%, the amount of discarded plastic going to landfill would increase the total weight of solid waste by 0.3%. This is about the same amount that would be saved by collecting plastics at the curb. Thus, if collecting plastics contributed to any increase more than 9.2% or more in plastic packaging consumption, initiating a curbside pickup program would actually lead to an increase in the amount of plastic sent to the landfill.

The degree of contamination affects the net cost of operation, because of the cost of sorting out unacceptable materials and landfilling the contaminants, and because any impossible-to-remove residual contamination lowers the value of the product. It is reasonable to expect costly rejection of entire loads if exacting specifications are not reached, as recyclers have experienced with other materials. In mixed-plastic collection schemes, the contamination problem is amplified.

Two basic strategies have emerged: one is to accept only certain types of plastic as indicated by the code number on the bottom of each container. While this approach lowers processing costs by providing some degree of separation at the source, the public must be educated and the curbside handlers must be trained. Truck drivers must invest considerable time in sorting at the curb and in providing educational feedback to the residents. The other strategy is to collect all types of plastic bottles and sort them at the processing location.