BROOKHAVEN TOWNSHIP

MUNICIPAL LEAF COMPOSTKNG REPORT

Sponsored by:

Highway Dcpartment, Brookhaven Township, New York

Harold H. Malkmes, Superintendent

Prepared by:

Ken Schwindt, Ecology Project Supervisor, Holtsville Ecology Center Timmi Nalepa, Education Coordinator, Holtsville Ecology Center

Glenn W. Munson, Project Consultant and Author

Abstract

Biodegradable paper refuse sacks are a cost-effective altcrnative to plastic bags for use in the municipal collection and composting of leaves, providing unique environmental advantages. Municipal employees engaged in collection and disposal and homeowner users report practical hands-on advantages.

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INTRODUCTJON

In thc fall ol 19S7, the Dcpartmcnl ol I-IighH'ityS ol Brookhavcn Township, New Yorl:, cslablislicd a pilot profrani to evaluate thc merits of using biodcgradable paper refuse si\Cks for municipal collection and composting ol leaves.

Thc purposcs were twofold. First, to compare thc clkctivencss ol leal composting in windrows nlildc of (a) loose leaves, (b) Icaves in plastic bags, and (c) leaves in rcc~cli\ble papcr bags. Sccond, to assess the trxleofh in using recycl~tblc paper bags ralhcr than plastic bags for municipal leaf disposal. What advantages or disadvantages would there be for homeowners? For collection and disposd crews?

This report sums up the data and obsewalions colleclcd during the ycarlong test project.

I BACKGROUND

A. BROOKHAVEN TOWNSHIP

Its 326 square miles make Brookhaven geographically the largest township in New York State. Locatcd 65 miles east of Manhattan, in Suffolk County, Brookhaven straddles Long Island from Long Island Sound on the north to the Atlantic Ocean o n the south. The central and southcrn two-thirds of Brookhaven a r c sandy pine barren, having oncc been a washout or flood plain lor a glacial moraine. T h e North Shore has good clay and topsoil, arid supports hardwood growth. Fall leaf and brush collection is mostly m a d c up ol oak with some maple jciives, and pine needles.

Brookl~aven's population was listed as 245.000 in the 1970 census. Growth incrcased steadily during the 70's and SO'S, and by the end of 1987 there were 415,000 pcrsons living in Brookhavcn, according to Long Island Lighting Company estimates.

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B. WASTE DEPOSAL

According to the town's Was te ManaEcni cn t Department, Brookhavcn genera t cs ninc pounds of solid waste per person pcr day. This figure is above the U.S. average of six to sevcn pounds (Europe is four and Japan, two), but includcs discarded appliances, furniture, land clcaring and construction materials, some of which are rccyclcd. Based on a 1986-87 solid waste analysis, an estimated 200,000 cubic yards (approximately 35,000 tons) of leaves arc collccted in Brookhaven every year.

Eight incorporated towns and villages within Brookhaven Township collcct their own solid wastc, including leaves, through municipal dcpartments o r private contractors. The Highway Department collects leaves and brush along the remaining 1,600 miles of roads. In the past, a substantial amount of leaves were collectcd loose using vacuum pickup or payloaders and dumptrucks, but loose collection is being discouraged for reasons given later in this report. The majority of leaves are put in 30-gallon plastic bags by homeowncrs who pile them a t curbside for pickup.

Brookhaven Township has four solid waste sites. The principal site is an 80-acre double-lined sanitary landfill which disposes all solid waste other than leaves, brush and recyclable materials. A smaller site accepts recyclable materials, brush, and leaves collected in plastic bags. Here, brush and woody materials a r e chipped for mulching use. Bagged leaves are composted in windrows for 18 to 24 months, then shredded before being used. Shreds and pieces of the nondegradable plastic make this process highly inefficient.

A third disposal site, the Holtsville Ecology Site, accepts only loose leaves or leaves collected in recyclable paper bags. These are also made into windrows for composting, with finished compost being used for highway and municipal landscaping. Compost is also available herc for use by Brookhaven residents in their yards, gardens and indoor plantings. The composting test reported here was conducted a t the Holtsville Ecology Site.

A fourth site, the Pine Road Holding Yard, is a 10-acre site used to hold leaf windrows until they can b e transferred to I-Ioltsville. It is strategically located in the north half of the township to cut down on travcl t imc to Holtsville during the busy leal collection season.

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C. HOLTSVILLE ECOLOGY SITE

The 145-acrc Holtsville Ecology Site was oncc iI town dump, thcn a Statc-opcratcd opcn-pit burning dump, thcn a sanitary Inndfill until i t rcachcd its limits and was covered with a final Iaycr of sand and soil, ilnd formed into hills and plateaus. New York Statc abandoned plans to operalc it as a park in 1975 and the Brookhaven Highway Dcpartmcnt took it over in 1979 for its growing Ecology Division.

Opcratcd by the Highway Dcpartmcnt, Harold H. Malkmes, Superintcndent, the Holtsvillc Ecology Site has been transformcd in a dcc;idc from an old d u m p into a rich community rcsourcc. Methane cxtrectcd from dccp within the old 1;indfiIl is burned to generatc elcctricity which is fcd into powcr company lincs, carning moncy for thc town. Grecnhouses on thc site are used Cor starting bedding plants for roadsidc and municipal plantings. I-Ioltsvillc also has an cxpanding native and barnyard animal preserve.

Once the site began to stabilize, public jogging and hiking trails, a fitness course, and picnic areas were established. An area adjacent to the animal prc-serve and a public compost pickup station is jointly opcratcd by thc Highway and Parks Departments and includes a n Olympic swimming pool, diving and wading pools, playgrounds, picnic and parking facilities.

Holtsville offers a variety of environmental education programs and provides environmentally-oriented guided tours to over 15,000 students a year, pre-school through college.

D. COMPOSTING

Brookhaven began composting leaves in 1970 and today uses a windrow com- posting technique developed during the early 70's. Payloaders build windrows approximately 20' a t the base and 10' high. The length of the windrows depends on the available space, but is commonly as long as 300'.

Windrows are made throughout fall and early winter, since residents rake yards from October into December, and road maintenance and repair take precedence. It's often January before the last windrons are h i s h e d . Even so, decomposition begins and the interior of the piles begin heating up immediately. Decomposition is well advanced by the following spring, and

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windro\vs are "turned" two or thrce tinics during summer and fall to mix coniposted mntcrials at the bottom core of the pilcs with the outer Iiryers of leaves which haven't broken do\$*n over the wintcr. If possible, windrows a re turncd during rain in order to add moislure as well as air throughout the rebuilt piles.

During the second summcr, after windrows have completely decomposed, the finished compost is put through a two-stoq Royer shredder before i t is used. Compost which bcgan as loose leaves shreds easily. Compost made from plastic- bagged lcavcs, however, is problematic. Although the bags have torn and rippcd apart, picccs and shreds of nondcgradablc plastic remain mixed throughout the pilcs. This requires the use of extra personncl to manually removc the pieces of plastic from the compost as i t exits the shrcdder. An additional downside is that largcr pieccs twine around axles in the shredding box causing the machine to jam, and the shredder must be run a t half speed to help overcomc this problem. Shredding plastic bag windrows is five to six: times more costly than windrows m a d e of loose leaves.

A study m a d e in 1985 by the Department of Agricultural Economics and Marketing at Rutgers University calculatcd thc retail value of leaf compost to be $7.40 per ton1 of original leaf volume, based on a Icaf-to-compost yield ratio of 5:l. At this rate, Brookhaven's annual compost production would b e worth over $259,000 as a cash crop. Although n o in-dcpth economic analysis, is available, we believe this evaluation would represent upwards o l 75% of the composting costs.

E. COMPOST USE

Whcreas Icaves buried in a landfill a re a wasted resource, Brookhaven reaps approximately 40,000 cubic yards (7,000 tons) of organic compost annually, calculated on the basis of 20% original volume (weight). With our 20th "harvest" in 1991, Brookhaven will have generated approximately 140,000 tons OF leaf compost.

The compost is used as a soil additive and mulch for highway, park and other municipal landscaping projects, and has been highly beneficial in revegetating and developing the Holtsville Site. Compost is mhcd with peat moss in the potting soil mixture used in the Noltsville greenhouses. T h e majority of this compost, however, has been made available f ree to homeowners for use in

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their flower and vegetable gardens, and indoor use, and tens of thousands of residents have taken advantage of this rcsource over the years.

Although leaf compost contains small nmounls of 16 essential elements requircd for plant growth, its principal value is as a soil conditioner. Organic mat tcr increases the soil’s ability to hold moisture, acts as a buffer against excessive acidity, alkalinity, and over-fcrtilization and increases the soil’s ability to hold plant nutrients for a longer period. By improving the tilth of the soil i t makes cultivation easier. A recent study shows tha t the presence of organic material in garden soil is an important factor in prevcnting the uptake of lead and other heavy metals by vegetables grown in the soil2. It should be noted, however, that extraordinary concentrations of lead must be present in the soil to pose a health threat, regardless oE its organic content. Further-more, although lead can be absorbed by plant roots and leaves, i t is largely excluded from the fruiting parts of plants such as corn, beans, peppers, etc.

Increasingly, homeowners call o r visit Holtsvillc to inquire about the pH and chemical makeup of our leaf compost. To answer these questions, we sent samples to the Pomology Analytical Laboratory, Cornell University, for analysis. The results a re presented in Appendix AB, together with EPA permissible safe levels for the elements by way of comparison.

I1 PROJECT DESCRIPTION

A. SCOPE

There are no practical alternatives to leaf composting. It is already illegal to landfill leaves anywhere in the s ta te of New Jerscy. New York has not m a d e landfill disposal of leaves illegal, but it has mandated that municipalities must recycle 50% of their solid waste by 1997. Leaves make up a n estimated 1520% of Brookhaven’s total solid waste, and are currently the most easily recycled portion.

Our goal of making leaf composting as efficient and inexpensive as possible is what prompted us to test paper bags for leaf collection and composting. Biodegradablc paper bags offered the promise of reducing the time required to shred compost collected in plastic bags.

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In tlic fall of 19S7, thc Highway Dcpartnient purchascd 400,000 biodegradable papcr Ecolobags from Dano Enterpriscs, in Plainview, New York. Through public information channels we offercd free Ecolobags to residents who would pick them up from a hdf-dozen Highway Deparlment yards tliroughout thc town. Municipal and private haulers were asked LO delivcr lhe filled paper bags to the I-Iollsville Site.

B. ECOLOBAGS

Although p;ipcr refusc bags have bcen availablc for at lcast two dccades, drawing somc public attention in the early 70's during the inilial cnvironmental movement, their major usc has bccn for industrial purposcs. Thc public is not familiar with these bags and they arc not generally available in supermarkets, gardcn centers and other retail outlels as yet.

T h e Ecolobag used in this project is a heavy-duty, weather-resistant folded paper bag made of two plies of 50# kraft paper, using a waterproof, nontoxic adhesive throughout. It can be printed with the town name or other information, using nontoxic ink which has been approved by the FDA for food packaging. It has a 16" x 12" square bottom and stands a waist-high 35". It is self-standing. It has a 30-gallon capacity, equal to t h e standard home trash can plastic lincr.

Although both a re rated a t a 30-gallon capacity, the Ecolobag holds 1% to 2 limes the leaves of a 30-gallon plastic bag. Holtsville personnel found they could usually empty the leaf contents of two plastic bags into one Ecolobag with energetic compacting. The paper bag's greater capacity in this application is d u e to its comparative strength. Plastic bags puncture and tear easily, whereas the paper bags are puncture-resistant. We put broken window glass, jagged cans and twigs in a paper bag, loosely filled i t with leaves, and threw i t around, letting jl fall t o earth. It did not puncture or tear with this ginger treatment. We submerged another in w-ater for 16 hours, then repeated this test. Evcn though waterlogged, i t stood upright without sagging, and did not tcar when we repeated the above test. (We subsequently lcarned that t h e Parks and Rccreation Departmcnt of Union, New York, uses the bags for litter deposit and collection throughout 14 parks and recreation areas because they withstand wcather, including freezing, for several weeks before weakening, and resist animal penetration.)

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C. TEST WINDROW

Early snouslorms divertcd equipmcnt and personnel to road-clearing, and thc six tcst windrows were made over a two-week period in late January and early February at the Holtsville Sile. They measured approximatcly 12' x 8' x 100':

a. loosc leaves on a sand base b. loosc leaves on a 6" base of compost c. paper bags on a sand base d. papcr bags on a 6" base of compost e. paper bags on 6" compost base, with a light

f. plastic bags on a 6'' compost base covering of compost over t h e windrow

Windrows b-d-e4 were built on a G" pad of leaf compost, while a-c wcre built dircctly upon the sandy soil found at Holtsville. This was done to study the eEfccts of inoculating loose, paper and plastic windrows to bctler understand its e fkc t s on the composting cycle. Windrow e, paper bags on a compost base, was also covered with a light layer of compost in order to assess the practical value of this extra step.

Test windrows were composted following our normal procedure. They were turned twice during the reporting period, on May 18th, during a light rain, and again on July 13th, following rain. This helped to add moisture as well as air throughout the reconstructed windrows.

D. DATA COLLECTION

Six thermometers were purchased in order to monitor pile temperatures. Four- foot lengths of PVC pipe were driven at a hcight of four feet, ang!ed down towards the center of each windrow. We purchased six tube thermometers from a scientific supply house to which we a f f i ed four-foot lengths of wire, bent on the end to hook over the outside ends of the plastic pipes. Temperature monitoring began on February 24th. A high-low thermometer was purchased to provide daily ambient tcmperature extremes. We noticed apparent discrepancies in its readings in the spring. The nearby Brookhaven National Laboratories is a National Weather Scmice station, and we have used their official daily ambient readings in this report.

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k t c n s i v e monitoring was not fcasible d u c to a limited Holtsville staff and a heavy workload. W c bcgan taking compost lcn~peratures at 9 a.m. and 1 p.m. Tour demands and other activities made this impractical and we felt thilt a single early afternoon reading would providc sufficient data Cot our purposcs. No cffort was made to take readings o n wcckcnds or holidays. By early spring, whcn school tour activity is greatest, i t was obvious that windrow Lempcrature fluctuations had smoothed out, and that less frcquent readings would be adequatc to track thermal activity. We took frequent rcadings again for brier periods following turning of the piles.

I11 RESULTS

A COMPOSTING

All windrows were built over a two-week period in late January and early February, when average ambient high temperature was 36.1°F, and low was 20.So* and extremes were 53.50 and 3". Typically, windrows show a burst of activity and steady rise in temperature over a two- to three-week period. When we began monitoring 'on February 17, however, windrows c-e wcre still some 40" cooler than the others. Since they had been built a few days later than the others, we bclieved they were still completing their initial warmup. Because of this, the graphs (see Appendix B) present windrow temperature readings from February 24 to Sept- ember 6, 1988. Ambient high-low readings are presented as figures at thc bottom of each chart.

Visual observation

Piles shrank slowly during the first four months. Windrow f , the pile m a d e from plastic bags, shrank noticeably m o r c than the others. We attributed this to denation of excess air in the plastic bags over the period.

When piles were turned o n May 18 we observed that loose leaves, windrows (a- b), were parlially decomposed and had fcw pockets of d~ leaves. The three windrows made from paper bags (c-d-e) were also partially dccomposed but had many dry pockets where paper bags had no1 broken opcn cither during handling or from decomposition. In was difficult to obsenie the dcgrce of decomposition of leaves in the piastic bag windrow (0 sincc very few bags split open during turning.

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There was lcss decomposition of IeiIvCS among tliose we could obscrve.

When the windrows were turncd the sccond time, on July 13, we found that all piles had brokcn down uniformly well, except for the plastic bagged lcaves (4. Remnants of paper bags were evident throughout windrows c-d-e, but homogcnization of decomposed bags and leavcs was well advanced. Many of the plastic bags seemed to rcmain essentially i n t x t , but were torn open during the sccond turning. Because thesc bags had acted as a barrier to decomposition, the lcavcs in thesc bags were only partially brokcn down.

Thermal observation

1. As indicated by thc graphs o n pages 00-00, the most efficient composting occurred in the piles of loose leaves (a-b). At first glance it appears that loose leaves on a compost base (b) perform better. They are 10” to 20” warmer during the first month. But from April 1 until the second turning o n July 13, loose leaves piled on the bare ground ( a ) perform as well as those started o n compost, except for the three weeks following the first turning. The h4ay 18 turning almost seems to have been a setback for windrow a. It would be interesting to know how this pile would have fared had it not been turned aiong with the others o n May 18.

Thc higher temperatures of both loose leaves windrows vs. bag windrows demonstrates that both paper and plastic bags act as barriers to decomposition during t h e first four-month period.

2. T h e plastic bag windrow (4 had second highest temperatures for three weeks then fell to the temperature ranges of paper bag piles (cooler than loose leaves) until the first turning on May 18. Its dramatically cooler temperatures than all other windrows during thc entire hlay 18-July 13 period indicates that the plastic bags remained essentially intact and continued to impede composting until most were torn o p e n during the second turning o n July 13.

As noted earlier, windrow f shrank noticeably more than all others during the first four months. There is a simple explanation for this. Plastic trash bags a r e m a d c of PVC, a material commonly used in food packaging as a n oxygen barrier. Whcn the bags a r e filled with leaves and closed, excess air is trappcd inside. T h e bags aren’t totally airtight,

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however,sincc closing docsn’t make a perfect seal and bags often havc small punctures from twigs and handling. This cxcess air is squcezcd from the bags by the weight of the windrow as time passes.

Four elements are required for aerobic composting: the lcaf fecdstock, microbial agcnts which cause decomposition (present on the leaves thcm- selvcs), watcr and air. As plastic bags lose air and compress, t h e plastic’s air barricr property increasingly acts to prcvcni air from circulating around the encloscd leavcs, slowing dccomposition. It was only at the second turning, when most plastic bags broke wide open, that the Ieavcs could decompose efficiently.

3.

4.

5.

6.

Decomposition spreads through the pile like a wave spreading out from the core. The process is faster and the temperatures highcr as thc lour elements (fecdstock, oxygen, water and micro-organisms) rcach optimal proportions. Too little oxygen or too much watcr, for instance, will slow down decomposition.

The effects of building windrows on a pad of compost was observable in two comparisons in this test. Loose leaves on compost (b ) had significantly higher tcmperatures during the first five weeks than loose leaves windrowed o n the ground ( a ) . Paper bags o n compost ( d ) and paper bags o n compost and covered with compost (e) show similar patterns. Both loose leaves and paper bag windrows start decomposing faster when they are made o n a bed of compost.

Turning windrows shortens the total composting cycle by mixing microbe-rich compost with leaves which provide new fuel. Temperatures indicate that plastic bag windrow (0 did not benefit from the mixing process a t the first turning on May 18. This is consistent with visual observations that a higher percentage of plastic bags remained intact after turning than paper bags.

Some plastic bags had split open by the second turning, and the rest appeared to open during the process, so that all piles benefited from mixing. Temperatures in all six piles dropped significantly, but were o n the rise a day later.

We looked at the paper bag windrow built on compost (d) and the paper bag pile on compost and covered with a thin layer of compost (e). The

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lattcr: was cooler for 12 d a y , then a good deal warmer for 23 days, and again cooler for the next 47 days until the windrom were turned on May 16 and, in fact, throughout the entire reporting period.

7. Of the three paper bag windrows ( c - d e ) , the ‘pile made on a sand base (c) had with few exceptions the lowest tcmpcratures. For three weeks, starting on h4arch 11, the paper bags on and covered with compost (e ) had higher temperatures than did paper bags on compost without cover (d). Yct the lattcr pile had highcr temperatures throughout the rest of llic monitoring pcriod.

B. COLLECTION

Homeowners

Nearly all the 400,000 paper bags picked up by rcsidents, found there way back here to Holtsville, mostly from pickup by Highway Department crews, o r by other haulers. Throughout the fall residents brought them to the Ecology Site in thcir cars or pickup trucks, most often taking finished compost back home with them for their own gardening use. Although we did not conduct a writtcn survey, the staff was able to ask two or three dozen residents why they had m a d e an effort to use the Ecolobags and what they thought of them.

Many said they had used the paper bags for environmental reasons, not surprising since all were familiar with Holtsville and used its compost or recreation facilities. Some pointed out that the bags had been free. When asked what they liked and disliked about the paper bags, the advantages most oEten cited were:

the bag’s strength bags don’t puncture and tear like plastic bags bags a re self-standing they fill through a top opening, while leaves must be swept or raked into partly filled plastic bags the waist-high opening saves bending over water -res is t a n ce

*

-

*

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Unfavorable commen 1s centered around bag closure and size. Sevcral users said they round thc bag difficult to closc and wished lhere wcrc sonic kind of built-in system for closing the bags easily and securely. hlost users closed the bags HS they would a grocery bag, by creasing in the sidcs and folding the top down two o r three times. This method of closing thc bag works fairly well, cspecially if thc bag isn’t crammed full to the top, but some users said the bag’s thickness made i t difficult to fold shut. A good many uscrs said that stapling the top m a d e closing easy and secure.

Sonic uscrs thought the bag was too snia11, and estimated its capacity lo be lcss than 30-gallon plastic bags. They found it hard to believe that we’d bcen able to dump the leaves from 1Y2 to 2 plastic bags into one Ecolobag.

Department personnel

T h e consensus on paper bags among highway crews was “No Problem.” Some of the crew did notice specific advantages in the paper bags which m a d e handling easier and more efficient.

It’s not uncommon for plastic bags to split open and spill their contents when picked up at the curb. When this happens, the crew has to stop to clean up the spill. IF the bagged leaves were unusually wet and had been left inside the bag for a long enough time, they produced a n especially rotten and unpleasant smell. (A result of anaerobic composting, this odor has been a problem in some municipal composting operations where windrows are too big and/or wet for adequate air t o be present3.)

Curbsidc spills are usually the fault of improper filling or tearing during use. And while they a re not a common occurrence, they happen olten enough to be a noticeable irritant and slowdown in collection. Road crews said thcy hadn’t had this problem with t h e paper bags. Paper bags weren’t always securely closed, and a few residents left filled bags standing opcn at the curb. But even if these had been knocked over, the amount of leaves which spilled from the open top could be quickly scooped up.

O n e other advantage was noticed by the road crews. “You don’t get soaked picking up paper bags aficr a rain, like you d o with plastic,” was the comment of one of the road crew. When partly filled plastic bags are left at thc curb, rain they collect hiddcn puddles in creases and pockets made by the material.

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IV

Hurried crews inevitably get wet over an cight-hour day, especially if plastic bags are collected during or just after a rain. This isn’t a serious problem, but i t doesn’t happen with the paper bags because of their heavier material.

We found no difkrences in handling paper and plastic bags in building and turning compost windrows. It’s clear, however, that the paper bags, which have now completely broken down into compost indistinguishable lrom the leaves, will shred as easily and quickly as composted loose leaves.

CONCLUSIONS

This project was designcd to look at collecting, composting and shredding re- cyclable paper bags, and to investigate their potential as an altcrnative to plastic bags for municipal leaf collection and composting. The project has yielded specific answers to some or our questions and provided a better understanding of factors involved if a switch to paper bags were to be seriously considcred o r eventually required by environmental legislation.

k COMPOSTING

1. Composted paper bags can b e shredded as quickly and inexpensively as composted loose leaves. The shredder does not have to b e run a t half-speed and extra personnel aren’t required to remove bag material, as is the case with plastic bags. This represents an important savings, although a n analysis of the specific savings has not been made.

2. Nothing is gained by covering windrows with a light layer of compost to justifj the added cost.

3. Nothing is gained by composting plastic-bagged leaves on compost.

4. A bed of compost provides an initial boost when composting loose leaves o r leaves in paper bags. Since all six windrows in our test will totally decompose within our two-year cycle, the added expense of a compost base appears unjustified. It could b e worthurhile for municipalities which have to minimize composting time, perhaps lor space reasons.

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13.

1.

2.

3.

4.

C.

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&perjence in thc early 70's suggested (and othcr studies have confirmed) that turning windrows not only reduced the time required lor complete decomposition, but also helped prevenl anacrobic (fermentation) conditions which can produce cxtremely ollcnsive odors. Even if therc is no reason to expedite the composting cycle, windrows must be prevented from turning anaerobic and rclcasing odors which could impinge on nearby residents. Our windrows are turned a minimum of thrce times during the cycle.

COLLECTION

Curbside collection of paper bags is somewhat more convcnient and efficient than collecting plastic bags. Collection crews are favorably disposed towards paper bags.

Homeowners find paper bags convenient to use, but cite closing as less convenient than plastic bags.

Although we found that paper bags can hold the leaf contents of upwards of 1% 30-gallon plastic bags i l reasonable effort is made to compact lcaves during filling, homeowners perceive the paper bags to b e smaller than plastic bags.

I t is unreasonable to expect homeowners, especially older residents, to compact leaves so firmly that curbside paper bags will hold the volume ol two plastic bags, evcn though we have proven this capability.

ECONOMICS

Recent bids submitted by bag supplicrs to Brookhaven Township show that recyclable paper bags cost $0.29 apiece, approximately 61 % more than plastic bags, which cost $O.lS each. Based on price comparison alone, few consumers would choose the paper bags at a retail store.

Yet our project has shown this off-the-shelf price discrepancy doesn't take into account othcr important considerations which may not b c apparcnt to the homeowner. For example, if homeowners filled paper bags with leaves equivalent to those held in 1% Dlastic baes. the

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useful value of plastic bags to paper bags would be $0.27 to $0.29. P a p c r bags would be only 7% more expensive than plastic bags.

h o t h c r critical economic factor, o n e not easily discernable by homeowners, is thc savings realized a t the shredding step in our coniposting program. A detailed analysis of the additional cost to shred and remove plastic from composted lcaves has not been made. But clearly the extra time and personnel requircd to shred plastic windrows is not insignificant. Twcnty years of csperience convinces us that our operating savings would morc than equal the 7% "premium" on paper bags described above, making the paper refuse bags lcss expensive than plastic bags.

Residents would not s e e these savings directly at the supermarket, as they d o not "see" the $259,000 market value of the leaf compost produced annually through o u r leaf recycling program. Nevertheless, they would derivc economic benefits from the paper refuse bags beyond the ecological benefits of sound environment management.

Our conclusion is that biodegradable paper refuse sacks are a cost-erkctive and environmentally sound alternative to plastic bags for use in municipal collection and composting OF leaves.

REFERENCES

1. Derr, Donn A. 1985. The economics of leaf composting. New Jersey Agricultural Experiment Station, Publication No. P-02550-2-85.

2. Bassuk, N.L. 1986. Reducing lead uptake in lettuce. HortScience. 21(4):993-995.

3. Judelson, Mark. Crystal Run Environmental Education Center's Leaf Composting Program. 1987. Spring Valley, New York.

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CHEMICAL ANALYSIS OF BROOKHAVEN LEAF COMPOST

Many Brookhaven gardeners who regularly use' municipal leaf compost in home gardens ask about the pH of the compost. A measure of relative acidity-alkalinity, a pH of 7 is considered neutral and the most favorable balance for most common garden vegetables.

Composting leaves are highly acidic, dropping as low as pH 4.5 in the early stages. By the time leaves have completely decomposed, the compost has become neutral, and Brookhaven's compost tests at pH 7.

Users have become increasingly concerned about metals in the soil--and metals which may be present in the compost they pick up at Holtsville, We remarked earlier that researchers are finding that adding organic matter to garden soil can help prevent uptake of metals by garden vegetables.

Because of concerns with metals in organic wastes applied to agricultural soil, especially from sewage sludge, the US. EPA has developed guidelines for the maximum safe addition of certain metals to soil. In conjunction with this project, samples of our compost was analysed by the Pomology Analytical Laboratory a t Cornel1 University. The chart below matches metals present in Brookhaven leaf compost with the EPA guidelines.

All figures are given in parts per million

METAL COMPOST EPA

Cadmium A251 25 Chromium 6.315 1000 Copper 11.28 1000 Lead 50.11 1000 Nickel 7.109 200 Zinc 52.76 2500

F E B R U A R Y 25 26 27 28

92 40 35 35 17 20 12 18

-li-

MARCH 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

I I

1 46 54 38 57 53 16 10 36 31 22 23 28 33 20 31 27 18 17 11 39 39

AMBIENTTEMP. ("F) HIGHILOW

a. LEAVES ON A SAND BASE b. PLAIN LEAVES ON A COMPOST BASE c. LEAVES IN PAPER BAGS ON SAND BASE ---+---- PILE f. LEAVES IN PLASTIC BAGS ON COMFOST d. LEAVES IN PAPER BAGS ON COMPOST BASE BASE

1111111111111111111 PILE e . LEAVES IN PAPER BAGS ON COMPOST 6 A AND LIGHT COVERING OF COMPOST ON 1

48 47 39 49.5 32 40 46 60 61

140

138

136

134

132

130

128

126

tf. 124

122

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U

W

Z - 116 W

I- a:

(IJ 120

n 118

5 1-14

g 110

5 108

4 112

k 106

104

102

100

98

96

94

92 53 59 52 64 53 69 52 44 31 30 27 29.5 48 41 37 41 32 40

AMBIENT TEMP. (OF) HlGHlLOW 33

LEGEND TW-----K--F~~--~- PILE a. LEAVES ON A SAND BASE ------------------- PILE e. LEAVES IN PAPER BAGS ON COMPOST B .*-----.--.--..- PILE b. PLAIN LEAVES ON A COMPOST BASE AND LIGHT COVERING OF COMPOST ON

PILE c. LEAVES IN PAPER BAGS ON SAND BASE ---̂.-*)-X PILE f . LEAVES IN PLASTIC BAGS O N COMPOST -1111.1-..111 PILE d. LEAVES IN PAPER BAGS ON COMPOST BASE BASE

!t -1

-1 I

W

0

$ W

t-

140

138

136

134

132

130

128

126

k 124 v)

122 Ct

W 0 118

116 W 5 114 t-

CI

(IJ 120

2 112

110 z w 108 t-

106

104

102

100

98

96

94

92

1 2 3 4 5

a9 63 67 55 41 36

LEGEND

6 7 8 JUNE

9 10 11 12 13 14 15 16 ' ' 18 19 20 21 22 23 24 25 26 27 28 29 30 I 1 2 3 . 4

AMBIENT TEMP. (OF) HIGH/LOW

w------~~--~-fl~-~- PILE a. LEAVES ON A SAND BASE -=----------------- PILE e. LEAVES IN PAPER BAGS ON COMPOST 6, -...-I*--_-.*-......- PILE b. PLAIN LEAVES ON A COMPOST BASE AND LIGHT COVERING OF CCMPOST ON

PILE e. LEAVES IN PAPER BAGS ON SAND BASE 7.- . -Y PILE 1. LEAVES IN PLASTIC BAGS ONCOMPOST PILE d. LEAVES IN PAPER BAGS ON COMPOST BASE BASE --------

% :1 I

ti 2

W

t- I-

2%

= w m z

a N

W

PW

WC

D

nw

I I

3 4 5 6

I4O r 138

136

134

132

130

128

126

k 124 m UJ 122 W U

W

' 116 W

I- Q 112 0:

110 2 w 108 I-

106

104

102

100

98

96

94

h

a 120

n 118

5 114

- __

-

- j v p

- .*I ++

,--"- a>

__

- - - - - - - - - - .-

-- - - __

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87 74

92 I

LEGEND .--wx--~-----"--- PILE a. LEAVES ON A SAND BASE =----=--------.---- PILE e. LEAVES IN PAPER BAGS ON COMPOST Bi .... - PILE b. PLAIN LEAVES ON A COMPOST BASE AND LIGHT COVERING OF CCMPOST ON

PILE f. LEAVES IN PLASTIC BAGS ON COMPOST PILE c. LEAVES IN PAPER BAGS ON SAND BASE F-*-,.rr**.c.Jxl

PILE d. LEAVES IN PAPER BAGS ON COMPOST BASE BASE ---C.--ll-