PREFACE

Autumn leaves, heralds of the harvest season, create quite a disposal problem. In the old days, burning leaves as the Fall clean-up was fun, but Halloween bonfires are only a memory. No one thought of air pollution or realized decaying leaves are necessary to continuing soil fertility. We be- lieved our land and i t s natural resources were endless, so we could waste, bury and burn.

The new concept is to conserve, recycle and use. This principle of ecology i s being enforced by legislation of government agencies for en- vironmental protection.

Under these new environmental regualtions open burning is banned, even approved incinerators with their necessary air pollution control de- vices are too costly for leaf disposal. To bury leaves as landfill is to need- lessly use up existing sites. Taxpayers will object to a new landfill area opening near them unless it is in some isolated swamp or marsh. These wet- lands are also protected by law to prevent water pollution, and, more im- portant, wetlands are necessary in the l i fe cycles.

Technology that made spaceships possible gave the astronauts the first vantage point of seeing Earth as it really is . . . the only spaceship with i t s own atmosphere. That atmosphere of air and water together with microbial soil life, reduces earth's wastes via decay, more efficiently than mans' methods of landfill, compaction or mechanical reduction of waste.

A few manufacturers of machinery designed for collecting, grinding, and shredding waste have cecommended using the natural principles of de- cay. The Royer Foundry and Machine Company is a leading manufacturer in this field - recycling waste, such as leaves, into a useful product. I am sure you will find this handbook, "Municipal Leaf Composting", the blue- book on municipal composting.

Stan Bulpitt

Darien, Connecticut July 1973

CONTENTS

PREFACE

INTRODUCTION

SITE SELECTION

Location Size Physical Characteristics

CO L LECTl ON SYSTEM

Equipment Crews and Schedules Policies

COMPOSTING OPERATIONS

Windrow Composting The Colony Aeration Temperature Moisture Acidity/Al kalinity CarbonfNitrogen Ratio Shredding and Turning Finishing Additives and Mixtures

APPLICATIONS FOR LEAF MOLD

COMMUNITY PROGRAMS

REFERENCES

ACKNOWLEDGEMENTS

INTRODUCTION

Municipal leaf composting is a recycling technique which is an important segment of the national program for environmental protection and ecology. It can be operated simply as municipal service, or the composting site can become the center for a total ecology program. In one suburban commu- nity, 34,000 population, the residents brought over 10.000 tons of leaves, grass clippings and other woody debris to the composting site within a ten- month season. About 800 cars per day come to the recycling area on week- ends to deliver these materials or to take away humus, wood chips, and firewood. Westfield, New Jersey has a fully operating Conservation Cen- ter and the entire community has become involved.

Leaf composting should be part of a total ecology program - a program with the support and participation of the community.

Developing this successful program for composting required careful plan- ning in all phases of the operation:

1. site selection, 2. design of a collection system, 3. management of composting materials, 4. utilization of finished materials 5. community involvement.

This guide outlines the major considerations in each phase of a municipal leaf composting program. Each community s t i l l must prepare an individual detailed plan for operations and for development of public support.

SITE SELECTION

A community usually has to select a composting si te from a limited num- ber of available locations. The decision must be based upon the projected traffic, as well as the basic physical requirements. Growth in the volume of leaves collected and, possibly, expansion to a complete ecology center should be anticipated.

Residents and commercial vehicles will bring material to the site. An attendent will be required during "open" hours to ensure other trash is not dumped.

Location The location selected should minimize the distance to be traveled by col- lection vehicles. Accessibility for residents to deliver material also is nec- essary. Traffic may be an important consideration i f several hundred resi- dents will visit the location on a weekend. The leaves will not create an odor or rodent problem, so a section of parkland or an old landfill could be considered a potential site.

Size If the volume of leaves to be collected is known from experience, the area required can be calculated from the size of the windrows. In typical wind- rows, (see Figure 11, one acre will be required for 7000 cubic yards of leaves. The experience of communities with established composting pro- grams can provide some guides for estimating the required areas. One rule i s to allow one acre for each square mile of the community. Another is one acre for each 30 miles of streets, assuming a home density of 800 to 1,000 per square mile. The area can be decreased if home density is lower. Some examples of existing sites are listed in Table 1.

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Table 1 Size of Composting Sites

Street Site Size Pop. Sq. Mi. Miles Acres - - Town -

Wellesley, Mass. 28,000 10 125 10% Westfield, N. J. 15,000 6 1 20 18* Scarsdale, N. Y. 19,000 6.5 90 4% Maplewood, N. J. 25,000 4 60 2 Tenafly, N. J. 15,000 4.5 60 4

* Ecology Center

Physical Characteristics The location selected for composting must drain well. In puddles of stand- ing water, the leaves will begin an anaerobic decompostion which creates an objectionable odor. A hard clay surface is preferred so equipment can be moved on the si te without bogging down in mud. This hard surface is particularly important if residents are invited into the area to dump yard debris. A paved surface may be utilized, but it is not recommended. (see ”Colony”) Experiments have demonstrated that street garbage, manures, sewage sludge and other wastes can be composted, but leachates from these ma- terials are potential pollutants. Sites which drain directly into streams and lakes should be avoided. I f materials other than leaves are to be composted, leachate may become a problem. Extensive engineering studies of drainage are required before these materials are incorporated in the compost. Wind- rows of leaves, grass clippings and woody debris do not create a leachate problem.

COLLECT1 ON SYSTEM

A municipal composting program requires a leaf collection system separate from other solid waste pick-up. Initially, the system probably will be a modification of existing procedures determined by the budget available for specialized equipment and for crews. Whatever system is adopted, the co-operation of residents and private collectors will be necessary.

Equipment Efficient vacuum leaf collectors are available to pick up loose leaves along residential streets. Vacuums are available as complete units and as satellite units to be used with existing trucks. Compared to other equipment, vacuum loaders have the advantage of compacting the loose leaves, reducing the number of trips required to the composting site. A volume reduction of 5-to-1 i s normal. Communities without vacuum equipment have utilized street sweepers and front-end loaders for the leaf collection program. In fact when leaves are wet, these units may be required to complete the pick-up of the leaves. Manufacturers of collection equipment can provide detailed specifications and can assist in planning pick-up schedules.

Crews and Schedules To provide an example of a collection system, Royer compiled data from several communities-in the metropolitan. New York area. Here, the collec- tion period i s 6 to 8 weeks, and, typically, collections are once a week. Five-man crews, with two trucks (16 cu. ft. boxes) and 1 vacuum collector are used in the example: 2 truck drivers, 1 operator for vacuum collector, 2 rakers. With the trucks alternately collecting and delivering to the composting site, the average crew will service 4 to 6 curb miles per day. The total number of crews required will depend upon the frequency of pick-up and total curb miles. The average costs for the communities in this example were $30 to $37 per curb mile for each pick-up - $180 to $222 per curb mile per season. This includes labor, maintenance, and equipment deprecia- tion for an average of 6 pick-ups per season. In another example with three-man crews and one truck per crew, the total costs are approximately the same. Idle time while the truck is enroute off- sets the saving of the smaller crew.

Policies Establishing a successful leaf collection and composting program requires community education, cooperation and possibly some ordinance changes. Residents must be in instructed to rake leaves to the curb, coordinating with published collection schedules. Provision should be made to allow

residents and private collectors a t the compost site. Generally,

to deliver leaves and other woody material a fee is charged for commercial users. such

as landscape contractors. Specific rules must be established and enforced to prevent the composting si te from becoming a dump for all types of solid waste. Plastic bags should not be permitted for curbside collection or direct delivery. Leaves sealed in plastic will putrify instead of decomposing through composting. In addition, the bags are difficult to separate from the finished humus. If bags are necessary for collection, bio-degradeable paper bags are available. These might be distributed by community organi- zations such as scout groups.

COMPOSTING OPERATIONS Even with a large volume of leaves careful management of the composting operation will ensure that decomposition is rapid and the site i s available for the next season's leaves. Composting is a natural process - very l i t t l e mechanical handling is required. The leaves will be converted to a useful humus, leaf mold. 1000 cu. yds. of leaves produce about 165 cu. yds. of finished humus.

Wind row Compost i ng Municipal leaf composting is a natural aerobic decomposition of organic material in specifically designed piles, or windrows. "Aerobic decomposi- tion" simply means that in the presence of air and mositure, natural micro organisms will break down the leaves. Although the biology and chemistry of the process are very complex, composting can be effectively and effi- ciently managed i f a few simple factors are understood. The windrows are designed to maintain the air, moisture and temperature required for com- posting and to minimize space requirements.

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Figure 1 : Windrow Construction. Recommended dimensions are noted. Surface leaves insulate the interior and help to maintain composting temperatures.

Usually, dumping the leaves and building the windrows will loosen com- pacted leaves. The recommended windrow dimensions are 10 feet wide a t the base and 8 feet high. (The length may be adjusted to fit the site.) (See Figure 1 .) To maintain adequate temperatures and moisture inside the pile, the width and height should be no less than 6 feet. Windrows should be a t least 6 feet apart so equipment can maneuver. To avoid a dry condition, the top of the windrow can be made concave to collect moisture.

The Colony The micro-organisms involved in composting include bacteria, actino- mycetes, fungi and enzymes. Many types of each of these are naturally present in the leaves and will become active under different conditions. Generally, all of the organisms consume oxygen, water, carbon and ni- trogen and give off carbon dioxide in the conversion of leaves to humus. Observation of the composting leaves will show which factors must be adjusted to sustain the activity of the colony. After a site i s used for several years, the soil will naturally innoculate the new windrows and speed composting. Therefore, a paved surface is not recommended.

Aeration Maintaining an adequate supply of air within the windrow is the most im- portant factor in managing leaf composting. The natural organisms require oxygen to convert the leaves to humus. With properly constructed wind-

Tines fastened to the bucket of a front-end loader make a mechanical pitch fork for turning leaves.

160-

140-- Typical Composting

Temperatures

im-. Thermophile

100 .. OF

80 _.

60--

20 -L

I I

Figure 2: Typical Comporting Temperatures. An adequate supply of air (oxygsn) is required to maintain the elevated temperatures generated by composting.

rows, the breakdown will be completed in about one year. If necessary the composting can be completed within a few months by frequently turning and shredding. Shredding the leaves increases the surface area of the ma- terial and hence, the exposure to available air. Turning the pile also will help to overcome the natural compaction that takes place as the leaves break- down. Shredding and turning also introduce fresh air within the pile. The optimum time for turning the composting windrows can be determined from observation of other factors - temperature and moisture.

Temperature The temperature within a compost pile changes as different types of micro- organisms become active. Initially, a t ambient temperatures, mesophilic organisms begin the breakdown, and this activity increases the tempera- ture. Above 1 10°F. thermophilic organisms become active, and the rate of composting activity increases. As the composting is completed, or if the available air and moisture are consumed, the temperature will return to the mesophilic range. Figure 2 shows a typical temperaturehime relation- ship for composting leaves. To complete composting of leaves as quickly as possible, the windrow internal temperature should be retained in the thermophilic range (1 10°-1600F) until breakdown is nearly complete. The temperature within a windrow can be easily measured. If it falls into the mesophilic range prematurely, aeration probably is required. Temperatures will drop temporarily after the windrows are turned. The recovery is rapid (within days) and themophilic activity resumes.

1 4 t 12

'10

PH 8

6

4

2

Typical Change in pH for Comporting Leaves t

I 1 I 1 I I 1

3 0 6 0 90 120 150 180 210 240 Days

Figure 3: Typical pH Chanqe in Compostina Leaves. Small variations in pH are ax- pected in leaf composting. Extreme acidity and alkalinity can slow decomportion.

Moisture Moisture i s required to dissolve the nutrients utilized by the active micro- organisms and to develop new cell life. The optimum moisture content in composting is 45% by wet weight. When too much water i s present, an- aerobic decomposition will occur. This is easily identified by the putrid odor commonly found in swamps and bogs. If this condition develops, the correction i s frequent aeration until the proper moisture content is obtain- ed. Proper drainage on the composting site is necessary to avoid anaerobic conditions during wet weather. If the windrows become too dry. moisture may be added; however, this should be done very cautiously. Generally, maintaining the proper shape and size of windrows is sufficient to maintain the moisture content above 40%. An observer with some experience can usually judge the moisture content. A measurement can be made simply by weighing a sample before and after drying a t 215'F for eight hours.

% Mositure = Original Weight - Dry Weight Original Weight

AciditylAl kal inity As the composting proceeds, the material will become slightly acidic then return to a near neutral condition which is retained in the finished humus. This change is not large (See Figure 3). Extreme conditions in either direc-

tion may inhibit the decomposition. I f an excessively acid or alkaline con- dition is suspected, samples of the compost should be submitted for a lab- oratory analysis and recommendations. For example, lime might be used to correct an acidic condition. pH correction seldom is necessary in leaf composti ng.

CarbodNitrogen Ratio The carbon/nitrogen ratio (C/N) is a measure of the nutrients available for the micro-organisms causing decomposition. Carbon is primarily an energy source; nitrogen is utilized in converting cellulose. Of course, leaves have a high cellulose content. Studies with various materials indicate that com- posting i s most efficient a t a C/N ratio of 30 (30 parts carbon for 1 nitro- gen). With leaves, the initial C/N ratio ranges from 60 to 80, and the fin- ished humus has a C/N ratio from 10 to 20. Therefore, the C/N ratio changes continually during the composting process. The C/N ratio could be used to determine that composting is complete, however, laboratory t e s t facilities are required. If composting is not proceeding normally, this test might reveal an unusual condition. Mixtures of materials have been used to lower the initial C/N ratio and speed the composting. For example, grass clippings have C/N ratio of 20, sewage sludge of 6-10, Sludge alone cannot be successfully composted. Before mixtures are utilized, the properties of the finished humus should be carefully checked, to ensure undesireable foreign elements are not in- troduced.

Shredding and Turning If composting windrows are properly constructed on a suitable site, the leaves will decompose naturally. All of the factors discussed above will be maintained near optimum conditions. After ten months, the leaves should be shredded and windrowed again. The volume will be reduced by about 5 t o 1. After the initial shredding, the temperature within the windrow will in- crease as the composting is resumed with a new supply of air. This humus will be fully composted and ready to use in the Spring. To accelerate the composting cycle, the windrows may be turned and shredded more fre- quently. Aeration prolongs the thermophilic composting activity. A Royer Shredder is uniquely suited for shredding, cleaning and aerating the compost. The tumbling action on the cleated belt mechanically breaks the friable compost, and the discharge further aerates the material as it i s piled. In addition, the Royer Shredder separates trash from the leaf mold. Cans, bottles, stones, sticks are removed so the finished humus i s clean.

Finishing When the composting cycle is complete, the leaf mold should receive a

A Royer Shredder will asrate and clean leaves during composting. During the first shredding much of the trash will be removed.

final aeration and cleaning. Most applications will utilize the material in bulk. A Royer Shredder will finish the humus and load it directly into trucks. The leaf mold also may be bagged for distribution to community residents. Commercial users may add nutrients to make a complete plant- ing mix.

Additives and Mixtures Additives may be employed to change the pH of the final product. Sulphur will make a more acid humus; lime a more basic product. However, com- mercial additives are not required to start, or maintain, the composting. With adequate air and mositure, the decomposition can be completed be- tween crops of leaves.

i

i

Finished compost should be aerated and cleaned before application or stockpiling.

Composting mixtures of leaves and other solid wastes is being evaluated by several groups. The initial results have been encouraging. The addition of sewage sludge and some industrial wastes, for example, could lower the initial C/N ratio and speed composting as well as add valuable nutrients. However, these mixtures must be tested very carefully because potentially dangerous materials might be introduced. For example, vegetables should not be grown in soil with high concentrations of the heavy metals that are found in some sludges. The studies with mixtures cannot be generalized, because waste materials vary from area to area. Each combination has to be evaluated individually. The high temperatures developed in composting destroy most, or all, of the potentially dangerous pathogens found in sew- age sludge and industrial wastes. Therefore, composting has appeared attractive for disposal of these materials. Again, each situation must be considered separately. Communities seeking to solve a leaf problem should not jeopardize the composting program by introducing a technically com- plicated and potentially dangerous mixture of materials to be handled. Government, university and industrial research later may demonstrate how the composting program can be safely expanded.

APPLICATIONS FOR LEAF MOLD

Leaf mold is a rich dark humus with a pleasant "earthy" odor. It can be utilized in applications that now require peat. However, leaf mold has the advantage of being a more uniform product. The primary value of humus is to retain moisture in the soil. It prevents erosion, extends fertilizers and generally improves appearance. It can be used to prepare a topsoil by mix- ing two parts of subsoil with one part leaf mold. Some sand may be added. The presence of the leaf mold helps plants utilize available nutrients in the soi I. Some specific applications for the leaf mold are:

1. Top dressing for turf in park land, athletic fields, golf courses, municipal grounds.

2. Erosion prevention and other roadside maintenance. 3. Land reclamation and cover for landfill areas. 4. Ornamental mulch for garden areas. 5. An amendment or buffing agent with fertilizers.

Utilization of the leaf mold in these community applications will result in a cost saving to offset some of the expenses of collecting and composting the leaves. One community has estimated the value of i t s annual yield of mold a t $1 0,000.

If the community cannot utilize all of the leaf mold produced, it may be sold to commercial nurserymen or to the residents. To gain public support for the program, the humus can be distributed to the residents as a part of a community ecology program. Advertising, a colorful package and a mar- ketable name (e.g. "Tenafly Humus") will help to promote the product and the program.

Top soil can be made for land redamation project by mixing leaf mold with poor rubsoil.

COMMUNITY PROGRAMS A municipal leaf composting program will require the cooperation of com- munity residents. First, land must be committed for the composting site. Then, a budget for equipment and operations is necessary. Residents also will be required to cooperate in the collection of the leaves. As the pro- gram begins, some objections may have to be overcome, but strong public support can be developed. A municipal composting program offers many opportunities for commit- ment in a popular "cause". Composting leaves i s a natural recycling pro- gram. - Ecology requires that organic materials be conserved,and composting eliminates the air pollution caused by burning. The composting site can even be part of an attractive park. The program will help beautify the community rather than create an unsightly dump and the utilization of the leaf mold in community projects will result in a measurable saving in ma- terial, a value which should be announced. Many communities have de- veloped specific programs to involve civic groups such as scouts, horti- cultural societies, womens clubs. These might be beautification, distribu- tion of collection bags, bagging humus for residential use, visitations to the composting site.

Succesrful community composting programs require public support. Distribution of the valuable humus is a direct return to the taxpayer.

The responsible agency should seek publicity for the leaf composting pro- gram. Local newspaper will cooperate and speaking engagements can be arranged. If other ecology programs are underway in the community, the leaf composting site might be part of an ecology center where glass, metal, paper, and other material can be collected. These centers can be- come the focal point of the community involvement. Responsible admin- istrators should not underestimate the importance of this element. The local program can become part of the national campaign for recycling and ecology.

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Tonge, Peter. Garbage into Gold, Boston, Massachusetts, The Christian Science Publishing Society, 1972.

Walter, Richard. "How to Compost Leaves", The American C i t L June, 1971.

"County Turns Plant Waste into Resource: Solves Landfill, Environmental Pressures", Rural and Urban Roads,February, 1973

"Money for Your Old Leaves", Organic Gardening and Farming, September, 1969.

Van Vorst, John R. "Four Leaf-Composting Communities," Compost Science, Vol. 13, No. 3 May-June, 1972

Looney, Nessa. "Brookhaven Tops in Ecology Program", Yankee Trader, December 1972.

Franz, Maurice. "This Town Accepts the Composting Challenge", Organic Gardening and Farming, July, 1971.

Gabaccia, A. J. "Composting Waste Sludge from Pharmaceutical Manufacturing" Compost Science, Vol. 1, No. 2

Wiley, John S., and 0. W. Kochtitzky. "Composting Developments in the United States", presented to Region IV Vector Control Conference, Biloxi, Mississippi, June, 1965.

Breidenbach, Andrew W., e t al., Composting of Municipal Solid Wastes in the United States, (SW-47r). Washington, D. C. U. S. Environmental Protection Agency, 1971.

Reclamation of Municipal Refuse by Composting, Technical Bulletin No. 37-9, Berkeley, Cal., University of California, June, 1970.

U. S. Environmental Protection Agency 1972.

Management, Third Annual Report, SERL No. 70-2, Berkeley, Cal., University of Cal., June, 1970.

Cincinnati, Ohio, U. S. Department of Health, Education and Welfare, 1968.

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McGauhey, P. H. American Composting Concepts, Washington, D. C.

Golueke, Clarence G. Comprehensive Studies of Solid Wastes

Hart, Samuel A. Solid Waste Management/Composting (SW-2c)

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Gaby, Nancy, Lynda L. Creek and W. L. Gary "A Study of the Bacterial Ecology of Composting and the Use of Protcus as an Indicator Organism of Solid Waste", Chapter 3, Volume 13 Developments in Industrial Microbiology, Washington, D. C. American lnstiture of Biological Sciences, 1972.

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Goleuke, Clarence G. Composting, A Study of the Process and I t s Principles, Emanaus, Pa., Rodale Press, 1973.

ACKNOWLEDGEMENTS

Reports of practical experience from communities with leaf composting programs were essential to the preparation of this guide. Royer is grateful to the cooperation of:

Stanley Bulpitt, Consultant Brookside Nurseries Darien, Connecticut

Everett Kennedy, Superintendent of Public Works We1 I esl ey , Massachusetts

Louis F. Mayersky, Director of Conservation Center Westfield, New Jersey

Kenneth Schwindt Highway Maintenance Foreman Brookhaven, New York

Grove Teates, President Leafco Wheaton, Maryland

John R. Van Vorst Superintendent of Parks Tenafly, New Jersey

Richard Walter, Supervisor Park and Shade Trees Maplewood, New Jersey