B R O O K H A V E N 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.
Brookhaven Leaf Composting Report
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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\blepapcr bags. Sccond, to assess the trxleofh in using recycl~tblcpaper 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 t h e 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.
'
B r o o k h a v e n Leaf Composting Report
B.
Page 3
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 timc to Holtsville during the busy
leal collection season.
Brookhaven Leaf Composting Report
C.
Page 4
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 composting 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
o n the available space, but is commonly as long as 300'.
Windrows are m a d e 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 t h e piles begin heating up immediately. Decomposition
is well advanced by the following spring, and
Brookhaven Led Composting Report
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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\$*nover the wintcr. If possible, windrows a r e 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 it is used.
Compost which bcgan as loose leaves shreds easily. Compost made from plasticbagged 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 it 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 are 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 m h c d 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 free to homeowners for use in
’
Brookhaven Leaf Composting Report
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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 mattcr
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 t o hold plant
nutrients for a longer period. By improving the tilth of the soil it makes cultivation
easier. A recent study shows that 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, it is largely excluded from the fruiting parts of plants such
as corn, beans, peppers, etc.
Increasingly, homeowners call or 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
are 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 state 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.
B;ookhavcn Leaf Composting Report
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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 are 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 t o 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 it with leaves, and threw it 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, it 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.)
Brookhaven Leaf Composting Report
C.
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TEST W I N D R O W
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
covering of compost over t h e windrow
f. plastic bags on a 6''compost base
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 f k c 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. Fourfoot 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 e d 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. W e 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.
Bioolihaven Leaf Composting &port
Page 9
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~peraturesat 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, it 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 September 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 (ab), 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 (0sincc very few bags split open during turning.
Page 10
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
(4had 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,
Bbokhaven Leaf Composting Report
Page 11
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 thcmselvcs), 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.
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 m a d e o n a bed of
compost.
4.
Turning windrows shortens the total composting cycle by mixing microbe-rich
compost with leaves which provide new fuel. Temperatures indicate that
plastic bag windrow (0did 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.
5.
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.
6.
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
Brookhaven Leaf Composting Report
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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 o r 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 are 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
Brookhaven Leaf Composting Report
Page 13
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 it
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 are not a common occurrence, they happen olten enough to b e 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.
Brookhaven Leaf‘ Composting Report
Page 14
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 it 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.
IV CONCLUSIONS
This project was designcd to look at collecting, composting and shredding recyclable 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.
Brookhaven Leaf' Composting Report
Page 15
5.
&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.
13.
COLLECTION
1.
Curbside collection of paper bags is somewhat more convcnient and efficient
than collecting plastic bags. Collection crews are favorably disposed towards
paper bags.
2. Homeowners find paper bags convenient to use, but cite closing as less
convenient than plastic bags.
3.
Although we found that paper bags can hold the leaf contents of upwards
of 1% 30-gallon plastic bags il reasonable effort is made to compact lcaves
during filling, homeowners perceive the paper bags to b e smaller than plastic
bags.
4.
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.
C.
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
Brookhaven Leaf Composting Report
Page 16
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 t o 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.
Brookhaven Leaf'Composting Report
Page 17
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
t o 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
Cadmium
Chromium
Copper
Lead
Nickel
Zinc
COMPOST EPA
A251
6.315
11.28
50.11
7.109
52.76
25
1000
1000
1000
200
2500
FEBRUARY
25 26 27
92
40
17
35
20
1
2
3
4
-li-
35
12
MARCH
28 1
18
I
I
1
46
54
16
10
36
38
31
5
6
7
8
9
10
11
57
22
53
23
48
33
47
28
12
13
14
15
39
20
31
AMBIENTTEMP. ("F) HIGHILOW
a. LEAVES ON A SAND BASE
b. PLAIN LEAVES ON A COMPOST BASE
c. LEAVES IN PAPER BAGS O N SAND BASE
d. LEAVES IN PAPER BAGS ON COMPOST BASE
1111111111111111111
--+--
16
17
49.5
27
18
19
20
21
22
23
24
25
32
18
40 46
60
39
61
39
17
11
26
PILE e . LEAVES IN PAPER BAGS ON COMPOST 6 A
AND LIGHT COVERING OF COMPOST ON 1
PILE f. LEAVES IN PLASTIC BAGS O N COMFOST
BASE
140
138
136
134
132
130
128
-tf.
m
126
124
122
U
120
(
I
J
W
n 118
Z
W
5
116
1-14
I-
4 112
a:
g
110
5
108
k
106
104
102
100
98
96
94
92
53
31
59
30
52 64
27 29.5
53
48
69
41
52 44
37 41
32
AMBIENT TEMP.
LEGEND
TW-----K--F~~--~-
PILE a. LEAVES ON A SAND BASE
-1111.1-..111
PILE c. LEAVES IN PAPER BAGS ON SAND BASE
PILE d. LEAVES IN PAPER BAGS ON COMPOST BASE
.*-----.--.--..-PILE b. PLAIN LEAVES ON A COMPOST BASE
(OF)
40
HlGHlLOW
------------------^
*
.
)
X
33
PILE e. LEAVES IN PAPER BAGS ON COMPOST B
AND LIGHT COVERING OF COMPOST ON
PILE f . LEAVES IN PLASTIC BAGS O N COMPOST
BASE
!t
-1
I
-1
t-
$W
W
0
JUNE
1
2
3
a9
55
63
41
67
36
140
4
5
6
7
8
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
138
136
134
132
130
128
126
CI
k
124
v)
122
Ct
120
W
0 118
(
I
J
W
5
t2
z
w
t-
116
114
112
110
108
106
104
102
100
98
96
94
92
AMBIENT TEMP.
(OF)
HIGH/LOW
LEGEND
w------~~--~-fl~-~.
.
.
I
*
_
.
*
.
.
.
.
.
.
-
--------
PILE a.
PILE b.
PILE e.
PILE d.
LEAVES ON A SAND BASE
PLAIN LEAVES ON A COMPOST BASE
LEAVES IN PAPER BAGS ON SAND BASE
LEAVES IN PAPER BAGS ON COMPOST BASE
-=----------------7
.
-
.
-Y
PILE e. LEAVES IN PAPER BAGS ON COMPOST 6 ,
AND LIGHT COVERING OF CCMPOST ON
PILE 1. LEAVES IN PLASTIC BAGS ONCOMPOST
BASE
%
I
:1
ti
2
W
t-
I-
a
z
m
w
2 %=
N W
P W
WCD
nw
I
I
3
I4O
138
4
r
5
6
-
136 __
134
-
132
-jvp
130
128
++
.*I
,--"a>
126 __
h
124
-
UJ 122
-
k
m
W
U
a
120 -
n 118
-
116
-
W
'5
W
I-
Q
0:
112 110 114
2
w 108 I-
106
-
104 -.
102
--
100
-
98
-
96 __
94
-
92
I
87
74
LEGEND
.--wx--~-----"---
---C.--ll-
....-
PILE a. LEAVES ON A SAND BASE
PILE b. PLAIN LEAVES ON A COMPOST BASE
PILE c. LEAVES IN PAPER BAGS ON SAND BASE
PILE d. LEAVES IN PAPER BAGS ON COMPOST BASE
=----=--------.---F-*-,.rr**.c.Jxl
PILE e. LEAVES IN PAPER BAGS ON COMPOST Bi
AND LIGHT COVERING OF CCMPOST ON
PILE f. LEAVES IN PLASTIC BAGS ON COMPOST
BASE