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Sa UNIVERSITY OF
Institute of Food and Agricultural Sciences
DEC 05 199
University of Florida
Municipal Solid Waste
Issues Facing Communities
MUNICIPAL SOLID WASTE COMPOSTING:
ISSUES FACING COMMUNITIES
Rebecca D. Dunning, Robert L. Degner, and P.J. van Blokland'
Increasing waste disposal costs and the growing need to satisfy state-mandated recycling and landfill
diversion goals have helped place waste management nearer the top of the community agenda. While landfills
remain the least expensive disposal option in almost all communities, they are becoming more costly due to
environmental regulations and more difficult to site due to public opposition. Municipal solid waste composting
is one waste management alternative that is being considered. Composting has the potential to reduce the
volume of wastes landfilled. If processed to user standards, composting can recover for recycling substantial
amounts of organic materials that would otherwise be landfilled. Clarification of waste management goals and a
consideration of the technological, economic, political and social issues of composting that face communities can
guide decision-makers as they consider the MSW composting option.
key words: compost, landfill, recycling, municipal solid waste, waste management
Preparation of this publication and a companion 35 mm slide set with the same title was supported by the
Extension Service, U.S. Department of Agriculture, and the Florida Cooperative Extension Service, University of
Florida under special project number 91-ESNP-1-5168. To obtain additional copies of this booklet and to borrow
the slide set, contact your local county cooperative extension service office.
'Ms. Dunning is a Research Assistant and Drs. Degner and van Blokland are Professors in the Food and Resource
Department, Institute of Food and Agricultural Sciences, University of Florida. Dr. Degner is also Director of the
Florida Agricultural Market Research Center.
uI!TivrITY OF FLORIDA LUBMr i
Municipal solid waste (MSW) is that portion of the waste stream that consists largely of household and
commercial waste that we typically term "garbage." Municipal solid waste composting is the controlled biologi-
cal decomposition of the organic material in MSW into a soil-like substance called compost.
When only construction and operating costs are considered, landfilling is the least expensive waste manage-
ment option in almost all communities. However, other options like MSW composting are becoming more
attractive for several reasons: (1) environmental regulations that are closing a number of landfills and making
new landfills much more costly to construct and operate (2) state recycling goals that require communities to
recycle a certain percentage of waste, or regulations that ban yard waste from landfills and (3) public recognition
of the "external" costs imposed by landfills such as threats to public health and environmental degradation.
Composting can reduce the volume of MSW organic by 25% to 50%. Since 55% to 70% of MSW is organic,
composting has the potential for substantial volume reduction of waste going to the landfill.
The raw materials or "feedstock" for the composting process are the biodegradable organic contained in
MSW. Feedstock composition varies by area and season, and this results in variability in the content of the
compost. This inconsistency, combined with a lack of defined quality guidelines for both producers and users of
compost, has been a major impediment to use of compost off-site from the landfill.
Compost can be used at the landfill for volume reduction of wastes going into the landfill, and as a substi-
tute for daily soil cover that can use up to 25% of landfill volume. Compost can be used away from the landfill as
a soil-amendment by government public works departments, farmers, landscapers, and homeowners. It is
estimated that in 1993 ten percent of compost produced was sold, and another 60% was given away.
Users and producers of compost have concern over the possible presence of trace metals, foreign matter (i.e.,
pieces of plastic, glass, and metal), pathogens, weed seeds, and pesticides in the compost. Other concerns relate
to the immaturity of compost that would be detrimental to plants, the potential long-term negative effects of
using compost for extended periods on lands, the potential liability of compost producers for crop failure or
detriments to public health, and the lack of standardized and regulated classifications for maturity and quality.
Definition of community waste management goals is an important first step in the evaluation of any waste
management alternative. MSW composting cannot eliminate the need for landfills and is but one potential part of
a community's integrated waste management plan. Consideration of the technological, economic, and social
and political issues related to MSW composting can guide decision-makers as they weigh the costs and benefits of
this waste management alternative.
The type and amount of MSW dictate what materials are collected, the size of the composting plant,
the type of processing technology windowo, vessel, etc.), and the type of output.
The method of collection and separation of MSW feedstock depends upon the type and sources of
feedstock, the costs of each alternative, the level of public cooperation (for example, if separation of
organic is made at the household), each state's regulations regarding the quantity and size of foreign
matter and level of trace metals permissible in finished compost, and the desired quality of the com-
post for potential uses.
The type of processing system chosen depends upon the composition and quantity of feedstock, costs
of each type of system, the end product desired, and state regulations that may govern production
techniques. Because MSW composting does not have a long, successful history, risk is an important
consideration. In recent years, several large and costly composting facilities have closed due to design,
management, and public relations problems.
MSW composting facilities are costly to construct and operate. Capital costs of the plants in operation
range from half-a-million to over forty million dollars. A sufficient supply of MSW feedstock should be
available to keep per unit (per ton) processing costs at a minimum.
The choice of processing technology will also be based on the infrastructure and methods of waste
management that already exist in the community. To accurately compare different technologies, the
change in costs and benefits should be calculated for the entire waste management system when differ-
ing compost technologies are included.
While high-quality compost has the potential to be sold, communities should assume zero revenue
from the sale of compost when making cost-benefit calculations.
The positive and negative effects on the local economy, such as on local employment and on producers
of compost substitutes, should be considered in the economic analysis.
Financial feasibility, the ability of the community to undertake debt financing to plan and construct the
compost facility, is also an important economic consideration.
Political and Social Issues:
MSW composting is more likely to be adopted in states that have high recycling goals, promote
composting with government procurement programs, and are actively developing compost quality
standards. Without political backing, MSW composting may be too costly and risky an option for
elected local officials.
Public support of a composting facility is a prerequisite for successful operation. Citizens are not likely
to support a costly political initiative unless they are convinced that adequate social benefits will be
realized. Composting faces much of the same public opposition received by landfills, plus additional
objections concerning possible dangers of long-term use of compost on public and private lands.
In 1993, there were 19 operating MSW compost plants in the U.S. In the early 1990's several large
compost operations were closed primarily due to odor problems, but facilities that remain open appear
to be controlling the conditions that result in odor.
In 1993, approximately sixty percent of the compost produced was given away, and ten percent was sold for
between $4.50 and $20.00 per cubic yard to farmers, landscapers, homeowners, and potting soil mixers. The remain-
ing 30% was landfilled, used as landfill cover, or stockpiled.
While all currently operating MSW composting facilities cannot be termed successful, composting is being
used successfully in some communities. MSW composting has helped communities achieve various waste manage-
ment goals, with the most often stated goal being that of extending the life of the landfill.
Table of Contents
Introduction ............................................ ..................................... I
Waste Management Alternatives: Municipal Solid Waste Composting .................................. I
What is M SW Composting ........................................... ........................... I
Composting as a Waste Management Alternative ........................................... 2
MSW Composting and the Landfill "Crisis"................................................... 2
Higher Costs of Landfills ............................................................... 2
Public Opposition ....................................................................... 3
State R regulation ................................................. ........................ 4
Summary: Integrated Waste Management and the Community................................ 4
Recycling Realities and Lessons for MSW Composting .......................................... 4
Some Myths and Realities of Recycling ..................................................... 4
Costs and Benefits of Recycling and Composting: Externalities and Avoided Costs ............ 6
Sources and Uses of M SW Compost ........................................................... 7
Composting Resources: What is the Feedstock?............................................. 7
Com post Quality .......................................................................... 7
Compost Uses......................................... ...................... . 8
Landfill Uses .................................................................... ... ....... 8
Public and Commercial Uses .................... .......................... ...... ...... 8
Objections to Use ..................................................................... 9
Issues in M SW Com posting .......................... .. ................................... .... ....... 10
Technological Issues .......................................... ............ ................... I10
Recovery of Material ............................................... ....................... 10
Processing of Material .................................................................. II
Expense and Efficiency ...................................................................... 13
State R regulations ......................................................................... 14
R isk ............................... ............... ................................. ........ 14
Technology and Economics ......................................................... ......... 14
Econom ic Issues ............................................ ................................. 14
Quantity of Feedstock ............ ..................... ................................... 14
Efficiency of Technology................................................... ................ 15
Value of the Finished Product ............................................................ 16
Effect on the Local Economy ....................................................... 17
F financial Feasibility .......................................... ............................... 17
Summary: Is it Right for Our Community? ................................................... 17
Political and Social Issues ............................................... 17
Need for Political Support............................................................................... 17
Form of Ownership ...................................... ................... 18
Public Opposition ........................................................... ... 18
Changing Public Perceptions ..................................... ....... 18
M SW Com posting Facilities ................................................................... 21
Characteristics of Facilities ................................................ .............. .... 21
Conclusions ..................................................... ......................... 22
Glossary for Composting .................................................................. 24
R eferences ........................................... .......................................... 2 25
For most of the past 50 years, communities
disposed of their municipal solid waste (that portion
of the waste stream that consists largely of house-
hold and commercial waste that we typically term
"garbage") in unlined excavations or "dumps"
owned by the city or county. A new term, "landfill,"
came into being as guidelines were specified as to
the construction and operation of these waste
disposal sites. The required use of a daily soil cover
of approximately 6 inches was one of the regulations
designed to reduce odors, dust, insects, the risk of
fire, and other perceived health hazards.
Much more stringent federal regulations for
landfill construction and operation were formulated
in 1988. These restrictions required that most
landfills be lined and comply with monitoring
programs continuing past closure of the landfill.
These more stringent, and more costly, regulations
have resulted in a term that would have once
been considered an oxymoron: the "state of the
This transformation from small city or county
dump to generally larger, much more expensive to
construct and operate modern landfill has generated
greater community interest in municipal solid waste
(MSW) management and alternatives to landfill use.
As cities, counties, and states grapple with the
growing costs of MSW management and landfill
siting difficulties, they seek alternatives
that are cost-effective and acceptable to citizens.
The composting of municipal solid waste is one
alternative to landfilling that is increasingly
SRegulations, cost, and height-
jfened social and political awareness
are leading to greater community
interest in waste management op-
tions like municipal solid waste
Cost minimization is likely not the only goal of
waste management. If this were the case, the search
for alternatives would probably end with landfills:
they still provide the cheapest option for waste
management in almost every circumstance.
Social and political goals can play as great a
role as economics in choice of waste management
methods. Confrontation with the public when
siting new landfills has intensified the search for
landfill alternatives, as have state regulations that
require greater recycling rates and diversion of
wastes from landfills.
This publication discusses the use of municipal
solid waste composting as a way for communities to
meet their waste management goals, and the issues
that communities are likely to face when considering
MSW composting as a part of their comprehensive
waste management plan.
SOLID WASTE COMPOSTING
WHAT IS MSW COMPOSTING?
Composting is defined as the controlled
biological decomposition and conversion of biode-
gradable organic material into a soil-like substance
called compost. Primarily through the control of
temperature, oxygen supply, and moisture, decom-
position that naturally occurs can be accelerated
several fold. Decomposition turns organic material
into water and carbon dioxide, which are released to
the atmosphere, while the remainder is converted
into a soil-like material. The loss of water and CO2
reduces the volume of organic by 25% to 50%.
Thus, composting of the organic in MSW can
reduce the volume that is landfilled, or virtually
eliminate organic in the landfill if the finished
compost can be used off-site.
fJ a Composting is defined
as the controlled biological
decomposition and conver-
sion of organic material into
a soil-like substance called
Two general categories of waste composting
are the composting of liquid waste, and the
composting of solid waste. There are about 160
liquid, or sludge, composting plants in operation.
The processing procedures and use of the end
product are fairly well-established.
The composting of municipal solid wastes, or
household and commercial organic garbage, is much
more limited. According to the Composting Council
and U.S. Conference of Mayors, only 19 MSW
composting plants were operating in the U.S. in
1993, processing an average of 66 tons per day per
facility. While regulations governing the processing
of waste into compost and the uses of the compost
exist in a few states, guidelines vary and no federal
rules, (such as those that exist for sludge
composting) have yet been adopted.
Food waste, wood, yard trimmings, and
paper-the biodegradable components of MSW that
decompose most readily-represent 55-70% by
weight of a community's waste.
Composting as a Waste
Waste management options include landfilling,
recycling, composting, and incineration. Although
composting is considered a method of recycling,
here we use the term recycling to mean returning
material back to its original use, and composting to
mean converting materials to an alternative use, i.e.,
a soil amendment. In 1992, 72% of MSW generated
in the U.S. was landfilled, 17% recycled, and 11%
incinerated. The 17% recycled includes about 2% of
yard waste composting. The trend for the past few
years has been less landfilling and more recycling
and composting, with incineration retaining about
the same percentage (Steutville & Goldstein, 1993).
Home composting has existed for thousands of
years, as has composting of agricultural wastes by
farmers. Large scale composting of yard trimmings
increased in the past few years as many states
banned the landfilling of this organic waste. By the
end of 1992, 22 states had banned yard trimmings
from landfills. As a result, close to 3,000 yard waste
composting operations were in operation in 1992, a
360% increase from the number in 1988.
While MSW composting received some atten-
tion in the U.S. in the 1960s and 1970s, it could not
compete with lower landfill costs. In Europe, where
a greater population density has created a more
pressing need for landfill alternatives, many coun-
tries have used MSW composting for decades.
SBetween 1988 and 1992, the number
of curbside recycling programs increased
from 1,050 to 5,404, the number of yard
waste composting plants increased from
651 to almost 3,000, and the number of op-
erating MSW composting plants increased
from 10 to 19 (Steutville & Goldstein,
MSW Composting and
the Landfill "Crisis"
Many citizens' first introduction to waste
management as a national public issue came with
the late 1980s national news coverage of the "gar-
bage barge." This garbage without a home plied its
way up and down the east coast of the U.S., unable
Figure 1. Materials Generated in MSW by Weight, 1990
(EPA Waste Characterization Study)
glass (6.7%) -
plostics (8.3%) '
food wastes (6.7-'
yard trimmings (17.9%)
wper od (6.3%)
-poper (31.5 7.A)
to find a landfill or incinerator that was willing to
accept its smelly load. The impression given was
that landfills were overflowing, and the few states
with existing landfill space should guard it lest they
become a dumping ground for other states.
The mental picture of overflowing landfills has
been reinforced by statistics which worriedly
explained that 50% of existing landfills would close
within 5 years.
The reality is that while some sections of the
country have been experiencing a landfill crisis,
others have landfill capacities to last half a century.
It is accurate to state that 50% of current landfills
will run out of capacity in 5 years, but this was also
the case in the 1970s and 1980s: most existing
landfills were designed to be in use for only about
It is also true that more than 1,000 landfills are
scheduled to close in 1994 in order to comply with
federal regulations that require, among other things,
that most landfills be lined to contain leachate.
However, most of the. 'ai scheduled for closure
are small and handle a small percentage of total
MSW. In 1988, approxim nil 'd% of landfills
disposed of less than 5% o'fldfilled MSW, while
larger landfills constituting 8% of the total number
of landfills disposed of 75% of MSW (Rathje, 1992).
Since many of the newer landfills are larger in size,
the number of landfills is dropping, while capacity is
increasing in some sections of the country.
Higher Costs of Landfills
As landfills close due to space limitations or
regulations, the need for new landfills is more
pressing in some areas than in others. A recent
survey of landfill capacity indicates that New
England states have an average capacity to last
just 4 or 5 years. In contrast, landfill capacities in
many western states are 40 to 50 years (Municipal
Table 1. Landfill Tipping Fees by Region of U. S., 1986-1992
Dollars per Tona
1986 1988 1990 1992 percent increase
North 43.97 55.33 61.47 65.83 209 19
Mid- 18.52 30.64 38.68 47.94 210 56
South 4.83 14.9 16.06 22.48 660 51
Mid-West 9.86 16.03 21.97 27.10 289 6
West- 5.21 7.70 10.50 12.62 167 64
South- 6.38 10.21 11.86 12.53 103 23
West 9.31 17.61 24.33 27.92 206 59
Average 9.91 20.59 25.21 31.20 304 52
"In constant 1992 dollars
While the capacity crisis is non-existent in
some areas, the costs of waste management are
increasing in almost every community. Costs of
siting landfills, construction, monitoring during
operation and after closure, disposal of leachate,
and other costs increase "tipping fees," the fee that
landfill operators charge per ton of waste taken in by
the facility. Table 1 documents this increase in
tipping fees by region of the U.S.
In the last decade there has been a greater
recognition of the environmental costs associated
with landfills. Leachatefroq landfills has been
identified as a possible source of ground-water
contamination and methane emissions from landfills
have been identified as a source of greenhouse gases
that contribute to degradation of the ozone layer.
The social unpopularity of landfills, typified by
the NIMBY ("not in my backyard") syndrome
presents as serious a problem as that posed by
higher costs of waste disposal. Due to the public's
perception of health and other risks associated with
landfills, the siting of new landfills has become
extremely costly, time-consuming, and in some
cases, impossible. Thus, although landfill alterna-
tives like recycling and composting programs are
generally more expensive than landfilling, their
social and political values help compensate for their
more expensive price tags.
Some communities are paying to transport
waste to other cities, counties, or even other states.
Avoidance of the attendant social and political costs
of siting a landfill plays a large part in the decision
to export wastes out of the community rather than
deal with them locally.
SThe social and political value
J of recycling and composting can
compensatefor their more expensive
price tags. %
While composting of organic wastes is not new,
most citizens and many community decision-makers
do not fully understand how composting technolo-
gies can be used for waste management. In some
communities, MSW composting might enjoy the
positive reaction that recycling has received in some
areas. Citizens who support recycling as a way to
"go green" and help the environment may equally
support composting as a way to increase the per-
centage of the waste stream that is recycled. In other
communities, however, MSW composting may be
perceived in the same negative light as landfills.
Even in communities that are not eager to
adopt recycling or composting, mandates are
bringing about change. Most states have mandated
that a certain percentage of the waste stream be
diverted from landfills or recycled. Some states have
banned certain materials, like yard trimmings, from
the landfill altogether. The more ambitious these
recycling and diversion goals, and the degree to
which they are tied to carrot and stick funding, the
more likely that a state will seek out alternative
methods of waste management.
State mandated recycling goals were in large
part responsible for the 400% increase in curbside
recycling programs from 1988 to 1992. Mandated
yard waste diversion resulted in a tremendous
increase in yard waste composting plants during the
same period. The fact that eight of the 19 operating
MSW compost plants in the U.S. are in Minnesota is
largely the result of that state's more stringent
recycling and diversion guidelines.
In the future, states like Rhode Island, which
has a 70% diversion goal while banning new incin-
erators, and New Jersey, with a 60% diversion goal,
are likely to spur many of their communities to
consider the composting option.
Summary: Integrated Waste Management
and the Community
Waste management has come a long way since
its humble beginnings at the local dump. Increasing
costs, environmental worries, more stringent regula-
tions, and the viability of a greater variety of waste
management options has resulted in increasingly
complex possible solutions. The community's
challenge is to integrate the array of waste manage-
ment options-landfills, incinerators, recycling
programs, composting-into an economically,
environmentally, socially and politically acceptable
way to deal with waste.
Increasing waste management fees and the
need to satisfy state-mandated recycling and diver-
sion goals have helped place waste management
nearer the top of the community agenda. The
following section addresses some of the possible
misconceptions that the public may have about
two growing areas of waste management-recycling
RECYCLING REALITIES AND
LESSONS FOR. MSW COMPOSTING
From 1988 to 1992, the number of curbside
recycling programs doubled each year. For the
most part, recycling programs have been favorably
received by citizens who believe that this small
investment of their time is a valuable contribution
to the environment. Disadvantages seem few:
what could be bad about turning waste into
something with value that can lower the costs of
While recycling does have many positive
attributes, it is not likely to result in lower garbage
fees. Since state mandates will probably result in
more curbside recycling programs, and more
composting, it is important that citizens be aware of
the realities of recycling. Following is a discussion
of several common misconceptions of recycling that
may also apply to MSW composting.
Some Myths and Realities of Recycling
MYTH #1: Recycling means less waste to the
landfill, and that means lower garbage bills.
REALITY: Greater collection and administra-
tive costs and possibly higher tip fees per ton of
waste mean that the adoption of a recycling program
will almost certainly increase the costs of waste
The costs of garbage collection generally
constitute 70% to 80% of the total cost of waste
management. The additional costs of collecting
recycled materials in their familiar blue or green
bins or from multi-family containers is the greatest
cost of recycling. Higher costs come from the
purchase of different types of garbage trucks, more
frequent pick-ups, and extra handling time. Cost to
administer the program and educate the public also
contribute to higher total costs.
S Given the greater collection and
administrative costs, the adoption of
a recycling or composting program
will almost certainly increase the
costs of waste disposal. on.
Higher collection and administrative costs can
sometimes be offset because there are fewer tons
that must be landfilled. However, when landfills
receive smaller daily quantities of waste, the tipping
fee per ton could actually increase; with a smaller
number of tons, landfills need more dollars per ton
to offset any "fixed" capital costs. These fixed costs
remain the same no matter how many tons of
garbage come into the facility.
It is difficult to obtain precise nationwide cost
comparisons for recycling, landfilling, and
composting. Both recycling and composting,
however, are considered to be more costly alterna-
tives to landfilling in most every circumstance.
While the average landfill tipping fee in the U.S. is
about $30.00, the costs of recycling programs are
reported to be from $120 to $130 per ton, even after
considering the revenues earned from the sale of
recycled materials (Allen, 1992). Since landfill
tipping fees vary greatly by area, however, recycling
and composting may be cost competitive in some
areas, particularly if the current waste management
plan includes costly incineration or transport to
distant landfills. Recycling and composting also
become more attractive as tipping fees increase
when more expensive lined landfills are constructed.
As integrated parts of the waste management
plan, recycling and composting may find their most
beneficial use in extending the life of landfills. Just
dodging the social and political minefields of siting
a new landfill may make recycling and composting
viable options despite their higher costs.
MYTH #2: Recycling means additional
revenue for the community, and that
means lower garbage bills.
Reality: The price received for recycled
materials is not likely to cover the additional costs of
a recycling program, and recycling is more likely to
increase waste management costs than decrease
As discussed above, the costs of recycling can
be four times or more than the current cost of
landfilling, largely due to greater collection costs.
The recyclables that are collected do have some
value; steel and aluminum cans, newsprint, plastic
and glass, are the materials most likely to be re-
manufactured and returned to their original uses.
As the number of curbside programs has
exploded, so have the quantities of bottles and cans,
newspapers and milk jugs available to be recycled.
In the short run, one of the basic principals of
economics is working against recycling: supplies of
recycled materials are greater than the demand for
them, and prices for the materials have fallen.
Mandated recycling programs or sheer community
enthusiasm for recycling has driven down the prices
of recycled materials. This has effectively made
recycling programs more expensive, at least for the
Mandated recycling programs
or sheer community enthusiasm for
recycling has driven down the prices
of many recycled materials by cre-
ating a supply greater than current
According to waste management firms, the
average ton of recyclables from curbside programs
was worth about $100 in 1988; in 1993 a ton was
worth $40. Part of this decrease could be due to
the change in what is being recycled-more plastics
and newspapers that bring a lower price per
pound compared to aluminum and steel that have
longer recycling histories, stronger demand, and
Newsprint provides one recycling price
extreme. In some areas the price of newsprint is
actually negative-the community pays to have it
taken away. Some cities have reportedly paid as
much as $40 per ton to get rid of newspapers
(Anderson & Strasma, 1993). The reason? Market
saturation. There is not enough demand to meet
the increasing supply. Distance from supply sources
to demand is also a problem. Newsprint may be in
demand in one area, but supply may be hundreds
of miles away. The costs of transporting a low
value, bulky material like newsprint will offset any
Marketing infrastructure, the ways to connect
buyers and sellers of recyclables, has also lagged
behind increases in supply. The result: lower
prices for recycled goods, and more costly programs
As supplies of recycled materials increase, the
only way to increase the price paid for recycled
goods is to increase demand. Demand will increase
if the perceived value of recycled materials in-
creases. This will occur if the price of virgin materi-
als increases, if new technology can more cheaply
turn recycled goods into products so that they are
more competitive with goods made from virgin
materials, or if the demand for products made from
recycled materials increases.
Reuse of recycled materials in the form of new
products is termed "closing the loop." It refers to the
fact that a material has only really been recycled
when it has been used again in a product. Stockpil-
ing recycled materials in warehouses does not
Some states and the federal government have
encouraged the use of recycled products, primarily
paper, through procurement legislation. The most
recent federal action was taken in late 1993 when the
federal government set minimum levels of recycled
content in federal government purchased printing
and writing papers to 20% by the end of 1994 and
30% by the year 2000. Government procurement
rules effectively increase the demand for recycled
materials, ultimately increasing the prices paid for
While a few states are adopting compost
procurement rules, most compost facilities struggle
with marketing. In 1993, only about 10% of the
MSW compost that was produced at the 19 operat-
ing facilities was actually sold. Ninety percent of
MSW compost was either landfilled, used as landfill
Table 2. Waste Management Alternatives
baseline = landfills
alternative additional costs avoided costs additional benefits
source reduction public education programs + landfill space + increased public
+ capital and operating costs of awareness
garbage pickup and disposal
+ environmental impact on
recycling to public education programs + landfill space + revenue from sale of
original use costs of disposal if cannot be sold +IF material is recycled to materials
additional costs for collection, original use: energy required + public awareness if
separation, and sale of materials to create product source separated
costs of pollution generated in collection +enviommental impact on
costs of marketing materials virgin resources
composting public education programs if source-separated + landfill space + revenue from sale
additional costs for collection, separation, + IF material is recycled of compost
processing, and sale of materials to soil use: + public awareness if
costs of pollution generated in energy required to source separated
collection and processing create product
costs of marketing materials + environmental impact on
costs of landfilling or incineration virgin resources
if cannot be sold or given away
incineration capital and operating costs + landfill space + revenue from sale
for processing of energy produced
costs of pollution from processing
cover, stockpiled, or given away. MSW compost has
a hard time competing with virgin substitutes-soil,
peat, and mulch-that are inexpensive and readily
available in most areas. Like newsprint, compost is a
low value, bulky item that is costly to transport.
MYTH #3: If we just recycle enough,
landfills will become obsolete.
REALITY: The combination of recycling and
composting can potentially divert 50-70% of the
MSW waste stream, but there will always remain a
portion that must be landfilled. Even if waste is
reduced to its lowest common denominator through
incineration, some materials like metal can not be
burned, and of the materials that are, 10% remain as
ash for landfilling. Even though recycling and
composting can never eliminate a community's need
for landfills, both can extend the life of the existing
or future landfills.
Costs and Benefits of Recycling
and Composting: Externalities and
If recycling and composting are likely to cost
much more than they could ever bring in as revenue,
what are the benefits to the community of incorpo-
rating them into the waste management plan? An
answer to this question requires consideration of
what economists call "externalities."
An externality is generally a cost, and one that
is usually difficult to quantify. These costs can
frequently be described in words, but perhaps not in
dollar terms. One example of an externality is the
pollution that a factory emits as a byproduct of its
processing. The pollution is a cost that is external to
the plant's operation, because the plant does not pay
anything for the ability to produce with methods
that create pollution. It may be difficult to deter-
mine the exact cost of an externality. In this ex-
ample, external costs include damage to the environ-
ment and public health.
If businesses or households did not pay for the
costs of disposing of their garbage, garbage would
be considered an externality. Some people argue that
the fees charged businesses and households for
garbage disposal do not cover the full costs of waste
management. They may cover the actual capital and
operating costs, but not external costs such as
lowered property values of people living next to
landfills, or the reduced quality of life caused by
noise and dust of garbage trucks.
If we can avoid an external cost-by extending
the life of one landfill so that another doesn't have to
be built, for example-then we have actually
avoided a cost. The cost may not be easily quantifi-
able, but it is real and should be considered with all
other benefits and costs when different waste
management options are discussed.
Table 2 presents the array of waste manage-
ment options open to the community, and the
change in costs and revenues that each could have
on the overall waste management plan. "Avoided
Costs" are just as explained above, and it is in this
column that benefits accrue from the use of recycling
I q All costs and benefits, both
quantifiable and difficult-to-
quantify, must be considered by
decision-makers. M /
When materials are recycled back to their
original use or another use, it is possible to forego
use of the virgin resource. This generates quantifi-
able savings in the form of materials cost and energy
savings, as well as the difficult-to-quantify avoided
costs of negative impacts on the environment. Once
all of the quantifiable and unquantifiable costs are
included, some waste management options that
seemed prohibitively expensive before may appear
SOURCES AND USES
OF MSW COMPOST
The composting of municipal solid waste
(MSW) can be viewed in two different, but not
contradictory, lights: as a means of waste manage-
ment and as a manufacturing process. The diversion
of waste from the landfill gives composting its waste
management function. The procedures used to
transform the resource (garbage) into a product
(compost) constitute the manufacturing process.
Composting Resources: What is the
The raw materials that go into the compost
manufacturing process are termed "feedstock." The
composting of liquid waste, or sludge composting,
was mentioned earlier. Sludge would thus be the
feedstock for this process.
The feedstock for MSW composting comes
from the commercial and residential waste illus-
trated in Figure 1. The MSW feedstock does not
include construction and demolition wastes. The
easily composted organic portion of the stream is
comprised of food waste, yard trimmings, wood,
and paper, totaling 55%-70% of the MSW stream.
About half of the 34% that is paper and paper
products could be recycled; the total organic
waste remaining after recycling is thus about 50%
of total MSW.
The feedstock for a composting operation
could combine both liquid and solid waste. This is
called "co-composting," and can involve the use of
human-derived biosolids or animal manure.
Sludge and manure are richer in nitrogen than
typical MSW, and a compost feedstock with a
greater nitrogen to carbon ratio leads to faster
decomposition. Within MSW, food scraps and
agricultural wastes have higher nitrogen to carbon
ratios, and accelerate the composting process while
providing a finished compost that is of greater value
as a partial fertilizer.
While the composition of MSW in any commu-
nity is made up of basically the same materials, the
percentages may vary widely by community and
season. Urban areas may have a smaller percentage
of yard waste and a larger percentage of food waste.
Yard wastes may equal 10% of MSW during some
months of the year and 40% during others.
S The variability of MSW
feedstock results in variable
quality of the ending compost-
a major impediment to wide-
spread acceptance and use.
Heterogeneity of the MSW feedstock can result
in a final compost of variable quality and consis-
tency. This variability and the dearth of defined
quality guidelines have been major impediments to
user acceptance of MSW compost.
A few states have created quality standards for
MSW compost, but classifications are still lacking in
most states. Federal guidelines have yet to be
established. Since potential users are identified
based on their demands for differing quality, com-
post manufacturers need to be able to classify their
compost into different quality categories. A few
states have specified classes or grades of compost.
For example, a state may specify four grades of
compost-A, B, C & D-with A designating better
quality compost that could be used by homeowners,
and D designating poorer quality compost that
could only be used as a substitute for landfill cover.
While the exact grading systems that do exist
differ by state, compost producers and users gener-
ally agree that higher quality compost has the
General Quality Characteristics
for MSW Compost
optimum moisture content to facilitate
handling or spreading
small number and size of foreign matter
low level of trace metals
greater maturity (biological processes are
soil-like smell and texture
free of pathogens and weed seeds
greater nutrient content depending on end use
In addition to these general quality factors,
certain users will have other requirements affecting
nutrient content, color, and other factors.
In some cases, simple landfilling of the
composted material may fulfill the waste manage-
ment goals of the community. Composting extends
the life of the landfill by reducing the volume of
organic MSW. Volume is reduced by 25%-50%
depending upon the composition of the waste
stream, the length of the composting time, and the
amount of rejected material screened out after
Composting reduces the vol-
ume of organic MSW by 25%-50%
depending upon the composition
of the waste stream, the length of
the composting time, and the
amount of rejected material
screened out after composting. M
Soil used as daily landfill cover uses up 20%-
25% of the volume of the landfill. If compost is
processed sufficiently to reach the quality standard
of landfill cover, this 20%-25% can be reclaimed for
waste, thus extending the life of the landfill while
avoiding the costs of purchased soil. Relatively low
quality compost can be used for this purpose.
Public and Commercial Uses
Better quality compost can be used away from
landfills by government agencies, farmers, and
homeowners. Following is a description of some of
the beneficial characteristics and uses of better
Compost used as a soil amendment is the
predominant stated potential use. "Amendment"
implies an addition of compost to existing soil. It
does not imply that the compost has any nutrient
value; rather, the addition of compost can potentially
improve the physical properties of soil. For ex-
ample, compost could be used on public roadsides
for establishment of groundcover and erosion
control, or it could be used by farmers to improve
moisture retention of sandy soils.
While MSW compost cannot substitute for
fertilizer, it can contain some low levels of nitrogen,
phosphorus, and potassium that may be released
slowly, and thus could reduce fertilizer use. How-
ever, unlike commercial fertilizers, the nutrient
content in MSW compost is low and highly variable
depending on the feedstock. If the compost feed-
stock contains a great deal of nitrogen-rich food
waste, for example, it will have a greater nutrient
content than a feedstock containing less food waste
and more paper and wood waste.
MSW compost may also contain trace metals,
such as boron, zinc, and copper, and thus could be
valuable for soils deficient in these metals.
While not generally promoted for this purpose,
research indicates that MSW compost can in some
cases act as an anti-pollutant, tying-up trace pollut-
ants and toxic organic compounds in soils, thereby
making them unavailable to plants (Cornell Waste
Management Institute, 1993).
For users in agriculture and horticulture,
research on the use of compost as a soil amendment
and partial fertilizer indicates that mature compost,
(although a standard test for maturity, like that for
quality, has not been defined), has promise to
improve yields for crops ranging from grains,
grasses, and pasture, to vegetable crops and silvicul-
ture (Shiralipour, et. al., 1992). However, in many
cases researchers are not sure of the exact reason for
the positive results, nor of the long-term effect on
the soil and crops. Reactions to compost are crop
and site dependent, and without definitive research
results, it has been difficult to generate commercial
demand for compost.
Objections to Use
User objections to compost have largely
centered on the possible presence of trace metals,
foreign matter, and pathogens.
The possibility that trace metals exist in the
compost and may be taken up by food crops or pose
a risk to humans in physical contact with the com-
post is probably the biggest fear of potential users.
"Heavy metals" is the term often used to refer to
potentially toxic trace metals. Those most feared
include cadmium, mercury, and lead which can be
harmful to human health even at relatively low
concentrations. These and other trace metals are
present in naturally occurring materials like yard
and food wastes, and in man- made materials like
plastic, batteries, and paints. Household items
containing trace metals may be overlooked in the
separation process preceding composting. Ground
up and composted, these metals do not degrade as
the MSW organic matter breaks down. Instead,
they become more concentrated during composting
since the organic matter which dilutes them gradu-
Conversely, metals in compost may be poten-
tially beneficial for soils deficient in them, and it is
possible that composts bind up some metals, making
them unavailable for plants.
These "possibilities," in the form of potential
hazards, worry users. Until users are made to feel
more confident using MSW compost, it will not
come into widespread use. While recent research
indicates that the fears of harmful concentrations of
trace metals in MSW compost are unfounded
(Epstein, et. al., 1992), concerns over cumulative
loading of compost (continued applications of
compost to the land over time) in the form of long-
term effects on the land have yet to be adequately
In addition to hidden dangers, the appearance
of some MSW compost is enough to deter its use.
The presence of foreign materials or "inerts"-small
pieces of plastic, metal, and glass-highlights
deficiencies in the separation process that have yet
to be cost-effectively solved. While inerts may not
be very noticeable when first applied, over time
rains bring the foreign matter to the surface. Com-
post with large amounts of inerts used on farm land
or used for land reclamation could come back to
haunt the community if that land is eventually
developed for residential or recreational use.
S Questions concerning
the effect of long-term use of
MSW compost will take time
Table 3. Compost Users and Applications
User applications primary quality considerations
public works departments Used as a replacement for purchased Better quality is needed
recreation departments top-soil for the following: where human contact is anticipated
city/county/state agencies landfill cover, land reclamation, More mature compost with greater
Soil for public works projects such as: nutrient content required if
highways and airport used for landscaping with
erosion control certain ornamentals
landscaping of new and existing
agriculture/silviculture Used as a replacement for topsoil Should be free of weed seeds, pathogens,
Used as a soil amendment risk of phytotoxicity, and
A partial fertilizer or fungicide high concentrations of heavy metals
Mulch for weed control Nutrient content requirements will
Erosion control vary by user
Maturity and appearance requirements
will vary by user, some states have
stricter guidelines on compost use for
Requires proper texture and moisture
content for ease of spreading
field nurseries Used as a replacement for purchased Nutrient content, maturity and
container plant production topsoil and peat and mulches for appearance requirements will
commercial plant production vary by user
and sale to wholesalers and the public Highest quality if handled by the public
Commercial landscapers Used as a replacement for purchased Must have a smaller quantity of foreign
topsoil and peat and mulches matter and little odor if for residential
in the following uses: or intensive recreational use
athletic fields, golf courses, residential
and commercial lawnsand gardens
The possible presence of pathogens, weed
seeds, and pesticides carried over from the feedstock
is also a potential danger. Sufficiently high tempera-
tures must be reached and maintained throughout
the composting process to destroy pathogens and
weed seeds and to neutralize pesticides.
An additional concern for agriculturalists
involves the danger of using compost that has not
been properly matured. MSW compost may need to
be cured for four to six months until the biological
processes have become stabilized. Immature com-
post can result in phytotoxicity (presence of acids in
the compost which can harm plants) or nitrogen
deficiencies. Nitrogen-poor compost can rob the soil
of existing nitrogen which is essential for plant
The presence of trace metals, inerts, and the
immature state of compost can pose a danger not
only to users, but to compost producers in the form
of product liability. Crop failures and effect on
public health are two potential sources of liability.
ISSUES IN MSW COMPOSTING
If a community is aware of all of the costs and
benefits of composting, it is in a good position to
judge whether or not MSW composting should
become part of the waste management plan. The
first step is to precisely define the goals of the
community. Possible goals could include one or
more of the following:
Possible community waste
(1) to minimize garbage disposal fees
(2) to extend the life of the current landfill
(3) to make the community more self-sufficient
in managing its waste (if currently
transporting for disposal outside of the
(4) to meet state's diversion or recycling goals
(5) to set up a demonstration project to take
advantage of government matching funds
(6) to generate greater public awareness and
responsibility for waste management
With the goals defined, the community is ready
to realistically consider the costs and benefits
associated with MSW composting. The remainder of
this publication discusses issues that communities
face as they consider the integration of MSW
composting into their waste management plan.
The compostable portion of MSW may be
extracted before or after waste collection. Hazard-
ous materials (such as batteries and lightbulbs that
contain trace metals), recyclables, and non-
compostables are separated by machine and hand.
The remaining material may then be shredded
before composting. Water, biosolids (sludge), landfill
leachate, manure, or other materials may be added
for nutrient enrichment or to speed composting.
A period of time passes, from days to months,
during which the compost may be mixed and
additional water, air, or other materials added. As
the biological processes slow, the material goes from
active composting to a slower rate of composting
called "curing." The slowing of biological degrada-
tion is tantamount to maturation of the compost.
When the compost has reached a state of
maturity desired by the end user, the material may
be screened to remove inerts such as pieces of plastic
and glass. Additional moisture or other material
may be added per user specifications. At this point
the compost is ready to be used.
Following is a more detailed discussion of the
processing steps and the issues confronting the
community as it reviews the different compost
Recovery of Material
The type and amount of MSW dictate what
materials are collected, the size of the composting
plant, the type of processing technology, and the
type of output. A "waste audit" should be con-
ducted to ascertain the quantity and quality of the
MSW feedstock. This audit identifies waste sources
and quantities, indicating the appropriate scale of
operations and type of system.
For example, urban areas with a great deal of
restaurant food waste may want to target these
businesses for collection. Since commercial garbage
collection rates are often volume-based and more
expensive than residential rates, businesses may
respond favorably to an offer to collaborate with the
city in composting.
A waste audit can identify
waste sources and quantities, in-
dicating the appropriate scale of
operations and most appropriate
type of processing system.
Rural communities with a great deal of agricul-
tural waste could make the same type of collabora-
tion with local farmers. In some states (such as
Florida, Massachusetts, and New Jersey), farmers
can compost on site, even collecting agricultural
wastes from off-site. In this way, some composting
is carried out without expensive capital investment
on the part of the city or county. (van de Kamp,
1992.) Communities considering this composting
option should carefully review state regulations that
distinguish an on-farm composting operation as an
agricultural enterprise as opposed to a much more
heavily regulated waste management facility.
Feedstock quality can determine the type of
processing and possible end uses. For example, a
community that generates a great deal of paper
waste can expect a slower decomposition rate and
ending product low in nitrogen. If the community
plans to sell the finished compost to nurseries, they
must adjust the feedstock or processing techniques
to fit this market niche.
The goal of collection and separation is to
maximize the amount of captured recyclables and
compostable material, while minimizing the amount
of non-compostables (including hazardous wastes)
that would appear in the finished compost.
Whether materials are separated at the source
(the household or business) or whether materials are
sorted at a centralized materials recovery facility
(MRF, pronounced "murph") helps determine the
type of compost processing technology and ending
Source-separation is a positive sort, with
individuals culling compostable materials like food
and paper waste from their garbage. For example, a
household might have three containers: one for
recyclables, one for compostable organic, and one
for all other garbage. Since successful source-
separation depends on public participation, it
requires public education and incentives.
MRF separation at a centralized facility is a
negative sort, with workers and machinery culling
materials that are not compostable from the total
amount of garbage. The facility may be a "dirty
MRF" which receives all mixed trash, or a "clean
MRF" that receives trash after recyclables have
already been removed by citizens.
It is not clear which separation method is most
effective overall. Source-separation produces a
cleaner compost but generally does not capture as
large a portion of the compostable organic as a
MRF. Compost that is from MRF separated feed-
stock has lower collection and separation costs, but
may contain more non-compostables and require
expensive post-compost screening to make it accept-
able for users.
Because of the problem of trace metals appear-
ing in finished compost, Europeans, who have a
longer history of MSW composting, are currently
moving more to the use of source-separated
programs to produce compost for unrestricted use
It is not clear which collection/
Separation method-source separa-
tion or centralized MRF separa-
tion-is more cost-effective.
Whether the community chooses source-
separation, MRF-separated, or a combination of the
two will depend on the type and sources of feed-
stock, the costs of implementing each alternative, the
level of public cooperation, the state's regulations
regarding the level of contaminants permissible in
finished compost, and the desired quality of the
If the material will only be used for landfill
cover, for example, the community may opt to
separate at a MRF, thus sacrificing "quality," which
is superfluous in this case, and gaining quantity.
Conversely, if the community is sure of a residential
market for high-value bagged compost, source-
separation and additional screening to reduce the
quantity of foreign matter may be required to meet
the highest quality standards.
Processing of Material
Once the materials are sorted, the compost-
ables are often shredded. Many sources of technical
information on composting encourage shredding
as a way to create more surface area to speed
composting. However, some compost facilities
do not shred because of the costs to purchase and
maintain the machinery and because shredding
reduces the particle size of glass and plastic, making
them harder to remove from the finished compost.
After pre-processing, materials are placed in
one of three basic mediums for composting: static
piles (aerated or not), windows, or vessel reactors.
The static pile ,"static" because it is usually not
turned, requires the least management attention, but
is the least efficient method of composting. Oxygen
and moisture, two important ingredients in
composting, are not evenly distributed throughout
the pile. The material on the outside of the pile is
likely not to compost thoroughly, while the material
on the inside of the pile may "go anaerobic"-
decomposition without oxygen-and this is the
reason for compost odor. None of the currently
operating MSW composting facilities in the U.S. uses
the static pile.
Oxygen deficiency in static piles can be solved
with the use of mechanical aeration which forces air
through the pile. This aerated static pile should
have less odor and faster decomposition than the
unaerated static pile. If the air is sucked from the
pile rather than blown through the pile, odorous
air can be collected and treated before being
released. Aerated static piles normally compost
for 6 to 9 weeks.
vf Static piles, windows, and
vessel systems are the three com-
mon MSW compost technologies
in use today. C M
Windrows are elongated piles with a width
approximately double to their height. Windrows are
placed on concrete pads to protect against leachate
runoff into the ground and to facilitate use of
turning equipment--either front-end loaders or
specialized window turning machines-that keep
the piles mixed and sufficiently aerated. Besides
aeration, mixing allows for moisture distribution
and moves material on the outside of the pile to the
inside where high temperatures accelerate
composting and destroy weed seeds and pathogens.
Turning is generally done several times a week
during the early stages of composting, but the
frequency of turning may decrease as the biological
processes slow and the compost reaches the curing
stage. Most facilities that use windows today are
composting from 8 to 20 weeks. Windrows and
aerated piles may be located outdoors, indoors, or
under open sheds. Enclosure is more expensive but
allows better control over moisture and odor.
The speed of composting is significantly
accelerated with the use of vessel reactors. Material
is placed inside tunnels, silos, or bins, which are
mechanically turned or agitated. Moisture and
oxygen levels can be closely monitored, and this
greater control over composting can speed the initial
stages of composting by as much as 10- fold. Vessel
reactors are often used in conjunction with aerated
static piles or windows: material is put in the
reactor for 3 to 7 days, then moved to piles or
windows for 2 to 6 weeks.
Active composting gives way to the curing
stage as biological processes slow. This is apparent
through a cooling of temperatures in the inner core
of compost piles. The curing portion of the
Table 4. Levels of Processing Technology
minimal: static pile or static windows
materials manipulation and processing characteristics pros and cons of use
little or minimal turning by front-end loaders pros:
little or no addition of moisture + minimal capital and operating costs
little or no monitoring of temperature, oxygen, or moisture levels + minimal technical expertise
minimal post-compost screening cons:
no addition of other materials during composting most odor problems during composting
-some parts of compost may not be mature, posing a danger
requires greatest time for composting (5-8 months or longer)
requires a large area (pad space) for composting
intermediate: aerated static piles, turned windows
more management control in form of monitoring of moisture, pros:
temperature, and oxygen + lower capital and operating costs than vessel systems
frequent manipulation ofwindrows or mechanical aeration + more control over compost quality
of piles or windows + better quality allows wider use of ending product
moisture added + faster composting than low level technology (2-5 months)
post-compost screening appropriate for end use cons:
requires large area for windows and window turning
aeration equipment needed for aerated static piles
manage to optimum levels of temperature, moisture, pros:
and oxygen + more homogenous ending compost quality allows
frequent testing of chemical and nutrient content to meet legal widest use
and end-user needs + fastest of all methods for composting (days to weeks)
may include addition of manure or sludge to speed composting + odors minimized
and increase organic content cons:
post-compost screening appropriate for end use requires greatest capital investment
-requires greatest technical expertise and operating costs
composting process is important--compost that is
not sufficiently cured can rob nutrients from the soil
to which it is added. Provisions should be made at
the facility for an area large enough to contain
compost for the curing period (and for storage if
finished compost cannot be immediately used).
After composting and curing, the material is
readied for use. Post-processing may include
screening, the addition or removal of moisture,
nutrient enrichment, and granulation or pelletiza-
tion to produce a more homogeneous product. The
objective is to make a more visually appealing
product and one that is easier to handle and use.
Table 4 summarizes the processing options
available and the major advantages and disadvan-
tages of each.
Expense and Efficiency
Of the three basic processing options, the
vessel reactor has the highest capital equipment and
operating costs but also provides the most control
over composting conditions while significantly
speeding the transformation from feedstock to
Aerated static piles (or aerated windows) are
generally less expensive than reactors. Mechanical
aeration provides some measure of control, and if air
is sucked through the pile it can be collected and
treated for removal of odors.
Other than the nonaerated static pile, which is
not in widespread use because it has the greatest
odor problems and risk of spontaneous combustion,
the window method is the least expensive process-
ing option. The advantages of lower capital and
operating costs, however, are offset by slower
composting and less control over temperature,
oxygen, and moisture. Windrows also require the
most land area, and this may substantially increase
investment costs for densely populated areas.
Some states regulate the production of com-
post. For example, some regulations specify the
composting temperature and the duration of el-
evated temperatures. Others specify the number of
times that windows must be turned per compost
cycle. Each community should be aware of existing
regulations and how these affect the design and
operation of the proposed facility.
In many cases the technology of composting
looks so promising that decision-makers may lose
sight of their original goals. This enthusiasm
combined with technology that has not been suc-
cessfully used on a large scale for sustained periods
of time creates the potential for costly mistakes.
Communities risk investing in operations that may
be made obsolete with technological advances or
government regulations. Community leaders
should visit operating facilities before making
financial commitments to equipment vendors.
Economic risks of the technology as well as its
feasibility should be considered.
Table 5. Choice of Technology
What materials should be recovered and how should they be recovered?
What is the type and amount of waste generated by the community?
Conduct a waste characterization study to identify the types, quantities, and sources of waste.
What collection and separation methods should be used?
Compare the costs and benefits of implementing source-separation or separation at a central materials
recovery facility (MFR).
How should the materials be processed into compost?
What type of processing technologies should be used?
Compare the costs of low level technologies like windows and static piles with high level technologies
like reactors. Consider the level of management required and expected return for differing qualities of
What are the state regulations on design and operation of the proposed facility?
What level of post-processing should be undertaken?
Compare different post-processing techniques required for different ending products.
Technology and Economics
Technologies are available to produce a high
quality compost with negligible foreign matter and
trace element metals. A combination of public
education programs and incentives to generate a
source-separated supply of clean feedstock, com-
bined with a state of the art MRF and the most
technically advanced processing operation can
produce a compost acceptable for virtually every
use. The question remains: At what cost? Which
technology, if any, is adopted by the community will
depend largely on economic and financial feasibility.
MSW composting is one element of an array of
interrelated waste management options-compost-
ing, recycling, landfilling, incineration-that depend
on a common waste stream. When considering any
new addition to current waste management
practices, the community should gauge cost-benefit
differences based on the impact on the entire waste
management system. When MSW composting is
added to the total waste management plan, do costs
increase or decrease? There are several key issues to
consider when comparing costs and benefits.
Quantity of Feedstock
Composting facilities require costly capital
equipment. Annual capital and operating costs can
vary from thousands to millions of dollars depend-
ing on the plant size and technology used. A small
community may simply not generate enough solid
waste to justify the construction of an MSW
composting plant. It might be possible, however,
for several communities to pool their financial
resources and share a common facility. The greater
amount of incoming feedstock would spread capital
costs over more tons of compost, resulting in a lower
cost per ton.
A larger community may generate a large
quantity of waste, but may already have landfills
and/or incinerators that provide adequate disposal.
For the compost facility to minimize composting
costs per ton, it must have a way to guarantee its
own supply of garbage. More guaranteed feedstock
usually translates into a lower per-unit disposal cost
because of economies of scale.
The guarantee of a supply of MSW is called
"flow control," and is an extremely important issue
for communities in which the composting facility
would be competing with cheaper landfills. Flow
control is normally secured in the following two
ways: economically, by subsidizing processing costs
so that the tipping fees can compete with landfills;
legally, by mandating that the community's waste be
taken to the composer as opposed to other available
means. Mandated flow control, currently legal in 26
states, can keep high-priced incinerators or
composters in business. Without flow control,
facilities could experience a "death spiral" of higher
tipping fees leading to less feedstock, resulting in
even higher tipping fees and the attendant loss of
feedstock. (Bailey, 1993).
While today's feedstock may justify a comp-
osting facility, what about the future? Lower courts
have banned flow control in some areas, and the
legality of flow control will be decided by the
Supreme Court in 1994. Without this legal means
of control, communities will likely need to subsidize
composters to compete with other waste manage-
The community can guaran-
e teeflow control through financial
subsidization or with govern-
ment regulations. R
Competition with recycling is another possible
problem area. Paper is one commonly recycled
material which is also potentially compostable.
With paper included in the waste stream, it may
be justifiable to incorporate composting into the
waste management plan. If the paper must be
recycled, the feedstock may not be sufficient to
support the facility.
Recycling and composting can be comple-
ments: recycling removes non-compostables like
metal and plastics, making MRF separation easier.
Final separation before composting can catch any
recyclables that were not taken out at curbside.
Composting can also utilize soiled paper that is
difficult or impossible to recycle. Even so, recycling
and composting programs can be very expensive,
and the community may simply not be able to
Efficiency of Technology
Based on existing infrastructure, public accep-
tance, and financial resources, each community must
calculate the costs of adopting different separation
methods and processing technologies. Separation
and processing will also depend upon the desired
final uses for the compost. To accurately compare
different technologies, the change in costs and
benefits should be calculated for the entire waste
management system when differing compost
technologies are implemented.
For example, a community may consider
combining an existing curbside recycling program
with source separation of household organic which
would be composted in open windows along with
yard trimmings. The additional costs of public
education, organic collection and transportation,
and compost processing would be added to current
waste management costs. Quantifiable items, such
as lower total landfill fees, as well as items that
would be more difficult to calculate, such as in-
creased public responsibility for waste management,
would also be included in the cost/benefit analysis.
Value of the Finished Product
Compost can be disposed of at the landfill-by
either landfilling directly or use as landfill cover-or
it may be sold or given away for other uses. For
some communities, direct landfilling of the
composted waste may be a desirable end for
composting: it gives the benefits of volume reduc-
tion without the need for costly compost processing
required to meet quality standards. If compost is
processed to landfill cover standards it can substi-
tute for cover material that can use 20% to 25% of
the volume of the landfill.
As a soil amendment, compost has the poten-
tial to be used off-site for many agricultural and
landscaping uses. However, MSW compost is not
yet widely accepted by users and the community
should assume zero revenue from compost when
making cost-benefit calculations. Of the MSW
compost generated at the 19 operating MSW facili-
ties in 1993, only 10% was sold. The real savings
benefit of compost use is the avoided costs of
If the community does plan to market the
material off-site, it will need expertise in determin-
ing the potential uses, producing the quality desired,
and marketing the product. The amount demanded
will depend largely on price and product quality
and consistency. Table 6 gives rough estimates of the
prices of competing products and illustrates that
capital and operating costs and production expertise
increase as desired product quality increases.
f Communities should as-
sume zero revenue from the sale
of compost when making cost-
benefit calculations. ft
The community should consider the existence,
size, and similarity of markets, and the distance
from the facility to these markets. Public agencies
using compost for land reclamation may have far
different quality and price requirements than do
growers of ornamentals for retail sale. Expensive
transport costs for this low-value, bulky material
will deter potential users. The lack of uniform
product standards may make it difficult for the
facility to gain user confidence. Further, existing
state standards for compost may change, perhaps
requiring the facility to make costly alterations in
Despite the uncertainties of compost quality,
one study estimates that the potential demand for
compost is 10 times greater than the potential supply
(Slivka, et. al., 1992). Like the market for recyclables,
however, connections between demand and supply
may be weak or nonexistent, and even producers of
top quality compost may be left without buyers.
Effect on the Local Economy
In some cases, the compost facility may find
itself in competition with existing suppliers of
compost substitutes, like topsoil, peat and mulch.
This potential negative effect on the local economy
must be compared to the positive effects, primarily
employment prospects, if the composting facility
Table 6. Compost Products and Approximate
Prices of Substitutes per Cubic Yard Sold
Possible Price Quality Costs
compost competing standards (plant
uses product (state specific) specific)
Retail $16-$25 T 1
(bulk/bag) t t
Sports $16-$20 + t
turf t t
Garden $8-$16 t t
centers t t
Nurseries & $6-$10 increasing quality increasing capital
landscapes (less foriegn matter and operating costs
Sand greater maturity) to reach quality
agriculture t t
Land $0-$4 t
reclamation t t
Sod $0-$4 t t
production t t
cover t t
Source: Tyler, 1993
Construction of an MSW composting facility
requires a large financial commitment that not all
communities will be willing or able to undertake.
Capital costs of facilities operating in early 1994
ranged from $536,000 to $42 million (U.S. Confer-
ence of Mayors, 1993). Added to the actual construc-
tion costs are financial outlays for waste manage-
ment planning-the creation of a set of waste
management scenarios and costs figures needed to
evaluate options. Further, costly public education
programs and government permitting may be
In addition to construction funds, consider-
ation should be given to future operating contingen-
cies. After construction, the facility may find it has
inadequate composting space or odor problems that
require costly modifications in the physical plant.
Competition from other waste management facilities
may require additional government subsidization.
In sum, even if MSW composting is an economically
viable component of the waste management plan,
the community may not be able to undertake the
additional debt financing required for initial con-
struction and operating contingencies.
Summary: Is it Right for
As with the choice of technology, costs and
benefits are site specific. Some communities may
be able to construct a facility on-site with a landfill
and under an existing permit; others may have to
make large financial and time investments to site
a new facility and build access roads or other
infrastructure. Some communities may find wel-
come public support for composting; others may
spend a great deal of time and money on costly
siting battles with citizens.
A 1993 California study provides an example
of the variation in waste management costs among
communities. Communities were asked to formulate
waste management plans that would meet the states
waste reduction goals. The overall costs for source
reduction and recycling ranged widely, from $6 per
ton to $122 per ton (Clumpner & Denn, 1993). The
estimates illustrate the differences in costs based on
choice of technologies and investments in infrastruc-
ture which vary widely by community.
State regulations on operating procedures and
quality of the final compost will also influence the
technology adopted and thus the final costs of
Table 7. Economic Feasibility
*Does integration of MSW Composting into the community waste plan increase or decrease total waste
Compare the change in costs and benefits of different composting separation and processing technologies
as they are added to the total waste management plan.
Is the feedstock sufficient to support a compost facility?
Does the community or county generate enough garbage to justify an MSW compost plant of sufficient
Who competes with the compost facility for feedstock?
How is feedstock flow assured for the future and how would changes in feedstock flow impact the costs
per ton composted?
What will be done with the finished product?
What markets are available for the different types of compost and for different prices?
Does the community have the expertise to supply existing markets and find new markets?
What are the full costs (production and transportation costs) of supplying markets?
What will be the effect on the local economy?
Will new jobs be created?
Will producers of compost substitutes (peat, mulch, blended topsoil) be impacted?
Is MSW composting a financially feasible alternative?
Can the community afford to finance all stages of planning, construction, and operation?
Is it right for our community?: site specificity
Based on the financial constraints of the community and the original goals, is MSW composting the best
method to integrate into the waste management system?
processing. The fact that state regulations regarding
MSW composting are still evolving adds an addi-
tional measure of risk to the composting option.
POLITICAL AND SOCIAL ISSUES
-i -ql -q -i -1 -q -q -q -1 q R -" -qq --q -"q- -q
Decision-makers at the community level are
being pressured from all directions to devise cost-
effective, environmentally-sound ways to deal with
wastes. Environmentally aware citizens want waste
management facilities that do not pose threats to
their health and quality of life; state and federal
regulations for landfill management and recycling
and diversion goals pressure decision-makers
/^ p Government procurement
programs reduce some of the risk
associated with composting
operations by ensuring a market
for compost. f
Even if a good case can be made for MSW
composting on technical and economic grounds,
without political and citizen support composting is
not likely to make it past the consideration stage.
Need for Political Support
MSW composting is more likely to be adopted
in states that have high recycling goals or promote
composting with government procurement pro-
grams which create markets for compost. Communi-
ties in states that fund research on compost use or in
states that are aggressively developing compost
quality standards can also likely expect greater
support for local initiatives.
Without political backing, MSW composting
may be too costly and risky an option for elected
officials. Facility siting may cause as noisy a
controversy as that of siting a landfill. Lack of
financial resources and time (5-7 years from plan-
ning to processing) may rule out MSW composting
as an option.
Additional considerations for metropolitan
areas are problems that may arise from disruption of
union contracts. Administrative costs which could
rise exponentially with added programs is also a
Form of Ownership
Communities have options for ownership and
operation of the composting facility. Different
combinations provide for differing degrees of
operational control, cost, and risk.
Table 8. Political and Social Feasibility
* Does MSW composting have political support from federal and state agencies and legislators?
Do current and proposed state recycling and diversion goals necessitate the use of composting?
Are there state procurement rules for compost?
Is the state in the process of developing rules on compost processing or quality standards?
* Can MSW composting be easily integrated into the community's administrative bureaucracy?
Will integration require costly new administration?
Will composting disrupt existing union contracts?
* What combination of ownership and operation gives the community the desired mix of operational
control and financial responsibility?
* What are the major points of public opposition, and how can these be addressed?
What are the major sources of public opposition, and how can current and future conflicts be resolved?
A facility that is wholly owned and operated
by the community (city or county), allows the most
control over operations. The drawback is that all
construction and operating costs are assumed by the
community, and this may include more government
administrative involvement than is desirable. With
control the public also assumes all risk: risk in the
form of possible increases in operating costs (due to
loss of feedstock, for example), charges for costly
repairs (as for control of odor problems), and
responsibility for any liability claims by citizens or
A firm that is wholly private leaves the com-
munity with the least control, but this means little or
no responsibility for financing. While zero financing
seems to imply zero risk, it is possible that the
private composting facility may fail, leaving the
community without adequate waste disposal.
Composting facilities can have a combination
of public and private ownership and operation. The
most common combination is public ownership with
private operation. This combination can take
advantage of financing and tax advantages available
for government-owned operations, avoid creation of
much additional government bureaucracy, and
exploit the efficiencies of private-sector operation
(Anderson & Strasma, 1993).
Community decision-makers must first make a
strong case that MSW composting is both technically
and economically a good waste management option
in the community. With strong political backing it
has a greater chance of clearing the final hurdle to
adoption: public acceptance.
Public support of a composting facility is a
prerequisite for successful operation. Citizens are
not likely to support a costly political initiative
unless they are convinced that adequate social
benefits will be realized.
The possibility of groundwater contamination
from compost leachate is one of the greatest public
health concerns. The potential presence of vermin,
birds, dust, and odors on site and near access roads
and the negative effects on surrounding property
values and community image are also of concern
For smaller communities, a waste management
facility may only be economically viable if feedstock
is brought in from other communities. While some
citizens may view this as a positive new business
venture that increases employment, others may react
negatively if they perceive that the facility turns
their community into a dumping ground for others.
These sources of public opposition are identical
to those facing landfills. Composting has an addi-
tional set of concerns, that involve the long-term use
of MSW compost on public and private lands. For
example, there may be concerns that crops grown on
land with MSW compost as a soil amendment may
be contaminated. The public may also fear contact
with the compost itself if it is used in parks or on
athletic fields, especially if large amounts are used
for long periods of time.
S In addition to the same public
ljyopposition received by landfills,
composting faces additional objec-
tions concerning the long-term
use of compost on public and private
Some less obvious concerns are risks to work-
ers exposed to airborne pathogens in the facility, fire
hazards from spontaneous combustion of the
compost piles, and the possible erosion of public
responsibility if an existing curb-side recycling
program is abandoned in favor of MRF-separation.
This latter concern goes back to the choice of
collection/separation technology. Environmentalists
are frequently opposed to dirty MRFs, not only
because these MRFs tend not to maximize the
amount of clean recyclables that curbside programs
do, but also because of the loss of public responsibil-
ity when citizens have no direct participation in the
waste management process. Use of dirty MRFs
could reinforce the public's perception that they
are not responsible for garbage after it leaves the
household, in contrast to recycling or source-
separated organic programs that help instill
public responsibility for the generation and
disposal of waste.
Changing Public Perceptions
A change in the public's attitude toward
composting and waste management in general may
be required to garner the support needed to incorpo-
rate composting into the waste management plan. A
change of lifestyle may also be necessary if the
community wants to base composting on source-
One way to deal with the public's possible
negative perception of composting may be to
promote the facility as a manufacturing plant.
However, compost should not be promoted as a
money-making enterprise-even if the compost
can be sold, it is very unlikely that revenues
from the sale of compost can ever cover the costs
If the community does not see monetary
benefits from composting in the form of lower
garbage bills, it must be convinced that there are
other social benefits. The composting facility could
be presented as a way to extend the life of the
current landfill, thus avoiding the need for siting a
new landfill. Foresight in meeting current and future
recycling goals is another possible justification.
MSW COMPOSTING FACILITIES
Characteristics of Facilities
As of late 1993, there were 19 operating MSW
and MSW/sludge composting facilities in the U.S.
The Pembroke Pines, Florida facility remained
closed as it continued to make renovations that
began in 1992. The New Castle, Delaware plant
closed its doors in 1993 but hopes to make improve-
ments to its odor control system and reopen at some
point in the future.
Table 9 lists some operating characteristics of
the 19 facilities plus Pembroke Pines and New Castle
facilities. Seventeen operators used mixed MSW and
four source-separated. In 1993 Mackinac Island,
Michigan changed to source-separated, because the
quality of compost from mixed MSW was too poor
to be used off-site.
Of the 21 plants, 9 use in-vessel processing in
conjunction with aerated static piles or turned
windows which are used for the latter portion of
composting/curing. Three use only aerated static
piles or aerated windows, eight use only mechani-
cally turned windows, and one uses a combination
of aerated static pile and turned window.
Six facilities are privately owned and operated
and 11 are publicly owned and operated. Four are
publicly owned but privately operated.
The average design capacity in tons per day for
the 19 operating plants ranges from 1.6 to 700, and
the average is 150. Many facilities are operating at
less than their design capacities. In most cases, the
plants were over-built for future increases in waste,
or builders took advantage of minimal cost differ-
ences between smaller and larger facilities. The
range of operating tons per day is from 1.6 to 250,
and the average is 66.
Three operators were receiving substantially
less feedstock than they had in the past. Two opera-
tors blamed court rulings against the legality of
mandated flow control (the Supreme Court will
rule on the legality of flow control for the nation
in 1994). As a result of the rulings, the facilities'
former suppliers of garbage are taking trash to
cheaper landfills, which in some cases are located
across state lines.
One operator had lost feedstock due to manda-
tory curbside recycling programs. This resulted in
less paper waste for composting and less intensive
use of separation equipment in the MRF.
All plants use some sort of screening after
composting, but not all plants shred before
composting. Eight of the 19 either just directly
compost, or only mix materials before composting.
Although many informational sources promote
shredding as a way to increase surface area for
faster composting, these operators mentioned two
reasons for not shredding: (1) to avoid capital and
repairs costs of shredding machinery (2) to keep
non-compostables, particularly plastic, in larger
pieces so that they could be more easily screened out
Despite screening, many operators complain of
inerts in the finished product. Interest was ex-
pressed in finding better methods to take out inerts
and finding a use for the preponderance of plastic
garbage bag film found in the final product. One
operator with no local lined landfill space com-
plained that his facility was still required to put
composted residuals (materials screened out from
finished compost) into expensive lined landfills,
while he felt the material should be put into cheaper
Approximately 10 percent of all
compost produced in 1993 was sold;
the remainder was given away,
landfilled, or stockpiled. 98
Six of the plants have odor control mechanisms
in place, and two of these planned to install addi-
tional odor control mechanisms. The remaining
plants said that they did not have odors or odor
complaints from residents, either because they were
located in rural areas, or were able to keep odors at
a minimum by turning compost piles frequently. In
the last few years, odor problems have caused the
shut-down of several large facilities-one in Port-
land, Oregon, another in Dade County, Florida,
and, most recently, the New Castle, Delaware
facility. However, as the MSW composting track
record lengthens, there seems to be a trend toward
better management control of the conditions that
result in odor.
Four of the 19 either directly landfill the
compost or use it as landfill cover. Two stockpile the
material until it can be cleared by the state for use.
Nine plants give the material away for use by
farmers, homeowners, or for public works projects.
Five sell the material for between $4.50 and $20.00
per cubic yard to farmers, landscapers, homeowners,
and potting soil mixers (one plant sells compost as
well as uses it as landfill cover).
Calculated as a percentage of the total compost
produced, just 10% of finished compost is sold.
Sixty percent is given away, and the remaining 30%
is landfilled, used as landfill cover, or stockpiled.
Communities had different reasons for build-
ing the composting operations. In most cases it was
to extend the life of the current landfill or because
there were no local lined landfills. One county
integrated composting into its landfill operation as a
way to get rid of leachate: leachate is spray irrigated
onto compost windows for faster evaporation while
it provides moisture for composting.
In another case, MSW was only used as a
bulking agent in a primarily sludge-composting
operation. The composting kept the community
from having to transport biosolids long distances.
While most operators are striving to produce a
compost that can be used by the public, the goals of
one facility were attained by simply landfilling the
material. The manager stated that his composting
process was valued for volume reduction and
because it could reduce leachate and methane
emissions of the landfill in the future.
Measuring the success of MSW composting in
the U.S. largely depends on how success is defined.
If it is defined as rapid growth in number of facili-
ties, like that experienced by curbside recycling
programs, MSW composting is not a success: there
were 10 operating MSW compost plants in 1988,
and there are 19 today. This is despite the fact that
compost authorities often point to a large number
of facilities in the "planning" stage: in BioCycle
magazine's annual (1988 to 1992) survey of MSW
compost facilities, it is consistently reported that
50 to 100 compost facilities are in the planning
stage. It is hard to decide whether this is a success
for composting, considering the widespread audi-
ence, or a failure, since so few facilities have actually
MSW compost's "success"
depends on how success is defined.
If success is measured by the revenues earned
from compost sold, MSW composting is not a
success. Ninety percent of all compost produced is
However, if success is defined as the adapta-
tion of developing technologies to a variable feed-
stock to reduce the volume of waste to the landfill,
MSW composting is a success. Depending upon the
technology employed and the characteristics of the
community, MSW composting may achieve the
waste management objectives of some communities
better than other available methods.
Table 9. Municipal Solid Waste Composting Facilities
name/location tipping design operating feedstock removes recyclables?/ shreds odor
start-up date fee tons per tons per day removed prior tor to r to control?
day arrival at facility? composting?
Lakeside, AZ MSW (75%)
8/91 $0 15 10-15 & Sludge (25%) no / no no yes
New Castle, DE 1350
3/84 $58.5 (230) 230 (MSW MSW (50%) yes / no yes yes
compost) for compost) & Sludge (50%
Escambia Co., FL
11/91 $30 400 250 MSW yes / no yes no
Pembroke Pines, FL
10/91 $61 220 0 MSW yes / no yes yes
Sumter Co., FL
3/88 $49.5 100 32-35 MSW yes / no yes no
Buena Vista, IA 70
12/90 $37 (35-40 35-40 MSW yes/ no yes no
Montogomery Co., KS
6/86 $16 300 50 MSW yes / yes no no
3/93 n/a 700 n/a MSW yes / yes no no
Mackinac Is., MI source-seperated
5/92 n/a? 1.6 1.6 MSW (35%) yes/ yes yes no
and other (65%)
Fillmore Co., MI source separated
8/87 $40 11 11 and mixed MSW yes / yes yes no
Lake of the Woods, MN source-separated
3/89 $40 10 5 MSW yes / yes yes no
8/91 $50 100 100 MSW yes / yes yes no
7/91 $87 500 150-170 MSW yes/ yes yes no
Pennington Co., MN $45 40 12 MSW yes / yes no no
St. Cloud Co., MN no (screens
7/88 $89 75 50 MSW no / yes for size) no
Swift Co., MN 40 source-separated
5/90 $80 (permitted 12.5 MSW yes / yes yes no
Wright Co., MN $89 165 110 MSW yes / no no yes
Sevier Co., TN 150 (75 150 MSW (81%)
10/92 $30 sludge) (35 sludge) & sludge (9'%) no / limited no yes
Whatcom Co., WA
12/91 $90 125 100 MSW yes / yes no yes
Columbia Co., WI
1993 $33 80 65 MSW yes / yes no yes
Portage, WI MSW &
9/86 $35 40 16 sludge (% n/a) yes/ yes no no
Sources: U.S. Solid Waste Composting Facility Profiles Vol. II, U.S. Conference of Majors; authors' communication with plant operators.
Table 9. Municipal Solid Waste Composting Facilities, continued
name/location composting and curing ownership/ market use, price % % % contact name
technologies and time operation per cu/yard sold rejected recycled composted and number
Lakeside, AZ in-vessel 3 days, then public/public potting soil 30% 0% 70% Phil Hayes,
11 weeks in aerated piles manufacturer, $6 Facility Manager
New Castle, DE in vessel 5-7 days, 30 public/private 75% for landfill 14% 66% 20% John Neyman
days more in windows cover, 25% land- (63% (302) 577-3457
scaping for $4.50 RDF*)
Escambia Co., windows, turned 1X public/public landfilled, 0% 5% 95% Drew Vanlandingham
FL per week for 3 weeks landfill cover Enviro. Control Coor.
Pembroke Pines, aerated static piles, private/private no production 15% 10% 75% Margie Rosenthal
FL 6 weeks in 1993 Publc Relations
Sumter Co., FL window, turned 2-4X public/public horticulture, 30% 15% 55% Terry Hurst
per week, 8-12 weeks homeowners, Facility Manager
landscapers, $10 (904) 793-3368
Buena Vista windows, turned 1X public/public landfill cover 30% 18% 52% Ellsworth Jeppeson, Jr.
Co., IA per week, 2-4 months (712) 732-7171
Montgomery windows, turned 2-4X private/private stockpiled 25% 10% 65% Mr. Carol Knisley II
Co., KS per week, 8-10 weeks Facility Manager
Baltimore, MD in-vessel tunnel, 18 private/private agriculture and NA NA NA Les Ward
days then aerated horticulture, n/a Facility Manager
piles for 30 days (410) 354-3000
Makinac Is., MI aerated static pile public/public stockpiled 30% 25% 45% Bruce Zimmerman
Public Works Director
Fillmore Co., MN windows, turned 1-2X public/public county, residents, 40% 20% 40% Neil Bremseth
per week, 12 weeks tree farmers & Solid Waste Adminstrator
landscapers, $0 (507) 765-4704
Lake of the Woods, windows, turned public/public landfill final 20% 26% 58% Gary Lockner
MN 1-2X per week cover Zoning Administrator
Martin/Fairbault in-vessel for 28 public/public agriculture, 32% 5% 63% Dennis Hanselman
Cos., MN days and 60 days landscaping, $0 Facility Manager
in aerated piles (507) 776-3232
Mora, MN aerated static pile for public/private forestry & 40% 8-9% 50-51% Dan Revard
6 weeks, then outdoor landscaping, $0 Facility Manager
windows turned 1X (612) 679-3412
per week for 4-5 mos
Pennington Co., windows, turned public/private agriculture 15-20% 50% (fuel 30% Richard Nordhagen
MN 2X per week & land pellets) President, Future Fuels
for 12-16 weeks reclamation, $0 (218) 681-3710
St. Cloud, MN in-vessel 3 days private/private agriculture & 30% 0% 70% Bob Deem
then aerated bed landscaping, $10 Facility Manager
for 39-45 days (612) 253-3668
Swift Co., MN windows, turned public/private agriculture & 20% 35% 45% Scott Collins
2X week public lands, $0 Facility Manager
for 16 weeks (612) 843-2356
Wright Co., MN aerated window, public/public agriculture, 35% 3% 62% Chuck Davis
60 days golf course, (612) 682-7331
Sevier Co., TN in-vessel 3 days public/private agriculture, soil- 30% 5% 70% John DeMoll
then aerated piles mixing, landscaping, Landfill Manager
for 6 weeks residents 10- (615) 453-5676
15% sold for $20,
Whatcom Co., in-vessel / private/private demonstration & 30% 10% 60% Frank Moscone
WA agitated bed research, $0 Pres. Recomp of Wash.
Columbia Co., in-vessel 1 week public/public agriculture, $0 30% 37% 33% William Casey
WI then covered window Dir., Waste Mgmt. Dept.
turned 4-5X per week (608) 742-6651
for 10-12 weeks
Portage, WI in-vessel 5 days to public/public landfilled NA NA NA Tom Pinnion
2 weeks then open Public Works Director
window turned as (608) 742-2595
needed for 8-12 weeks
Sources: U.S. Solid Waste Composting Facility Profiles Vol.
* RDF = refuse derived fuel
II, U.S. Conference of Majors; authors' communication with plant operators.
The following organizations conduct research,
publish and/or distribute information free or for a
fee, and provide training programs.
The Composting Council
114 S. Pitt Street
Alexandria, VA 22314
(703) 739-2401 FAX (703) 739-2407
Cornell Waste Management Institute
Center for Environmental Research
468 Hollister Hall
Ithaca, NY 14853-3501
1794 Columbia Road, NW
Washington, DC 20009
Environmental Protection Agency
The EPA in your state has a variety of publications
and you may be able to reference these through a
Institute For Local Self-Reliance
2425 18th Street NW
Washington, DC 20009
(202) 232-4108 FAX (202) 332-0463
381 Park Avenue South
New York, NY 20009
Institute for Sound Environmental
19 Girard Place
Maplewood, New Jersey 07040-3107
Publishes Composting Frontiers
(201) 762-4912 FAX (201) 761-5415
National Composting Program
U.S. Conference of Mayors
1620 Eye Street NW
Washington, D.C. 20006
National Solid Waste Management Association
1730 Road Island Avenue
Washington, DC 20036
Publishes Waste Age magazine
1-800-424-2069 FAX (202) 775-5917
The Solid Waste Association of North America
P.O. Box 7219
Silver Spring, Maryland 20910
(301) 585-2898 FAX (301) 589-7068
Your local or state cooperative extension office can
also refer you to different sources of information.
Waste management institutes or agencies are in all
states. Check with your state university.
Trade Magazines and Journals
18 South 7th Street
Emmaus, PA 18049
1730 Rhode Island Avenue, N.W.
Washington, D.C. 20036
1640 5th Street
Santa Monica, CA 90401
P.O. Box 10540
Portland, OR 97210
Articles on the use of compost also appear in
trade magazines for specific users, such as Lawn and
Landscape Maintenance, American Nurseryman, and
Articles on compost also appear in scientific
journals such as Biomass and Bioenergy, Journal of
Environmental Quality, Soil Science and Plant Nutri-
tion, and many others.
Glossary for Composting
The following glossary is adapted from defini-
tions used by the U.S. Conference of Mayor's
National Composting Program, the Composting
Council, and the U.S. EPA.
Aerated static pile A composting system that uses
a series of perforated pipes (or equivalent) as an air
distribution system running underneath a compost
pile and connected to a blower that either draws or
blows air through the pipes. Little or no pile turning
Aeration (for composting) The process of exposing
bulk material,such as compost, to air.
Aerobic A biochemical process or condition
occurring in the presence of oxygen.
Anaerobic A biochemical process or condition
occurring in the absence of oxygen.
Biodegradable A product that can be broken down
by microorganisms into natural elements such as
water and carbon dioxide.
Co-composting Simultaneous composting of
two or more diverse waste streams, one of which
is often sludge.
Compost The relatively stable decomposed organic
material resulting from the composting process.
Also referred to as humus.
Compostable Organic material that can biologi-
cally decomposed under aerobic conditions.
Composting The controlled Biological decomposi-
tion of organic waste under aerobic conditions.
Curing The last stage of composting that occurs
after much of the readily metabolized material has
Decomposition The break down of a material into
component parts or basic elements.
Flow control A legal or economic means by which
waste is directed to particular destinations.
Ground water Water beneath the earths's surface
that fills underground pockets and moves between
soil particles and rock, supplying wells and springs.
Inerts: Non-biodegradable products contained
Integrated Solid Waste Management A practice of
using several alternative waste management tech-
niques to manage and dispose of specific compo-
nents of the municipal solid waste stream.
In-vessel Composting A composting method in
which the compost is continuously and mechani-
cally mixed and aerated in a contained area.
Leachate Liquid which has percolated through, or
condensed out of, mixed municipal solid wastes and
has extracted, dissolved, or suspended materials
from the waste.
Materials Recovery Facility (MRF) A facility to
recover recyclable materials from the waste stream.
Methane An odorless, colorless, flammable, and
explosive gas produced by municipal solid waste
undergoing anaerobic decomposition.
Municipal Solid Waste (MSW) Includes non-
hazardous waste generated in households, commer-
cial and business establishments, and institutions.
Organic waste Waste material containing carbon.
Pathogen An organism capable of causing disease.
Phytotoxic Something which is detrimental to
Recycling The process by which materials other-
wise destined for disposal are collected, reprocessed
or remanufactured, and reused.
Source-separation The segregation of specific
portions of the waste stream at the source of genera-
tion (usually the home or business) to facilitate
recycling and collection, remove hazardous wastes,
and remove inorganics unsuitable for composting.
Tipping fee A fee, usually dollars per ton, for the
unloading or dumping of waste at a landfill, transfer
station, recycling center, or waste-to-energy facility.
Toxin Compounds that cause a reduction of
viability or functionality in living organisms.
Trace element metals (heavy metals) Trace ele-
ments whose concentrations are regulated because
of the potential for toxicity to humans, animals, or
plants. Includes copper, nickel, cadmium, lead,
mercury and zinc if present in excessive amounts.
Vessel Composting A composting method in
which the compost is continuously and mechani-
cally mixed and aerated in a contained area.
Waste stream A term describing the total flow of
solid waste from homes, businesses, institutions and
manufacturing plants that must be recycled,
composted, burned, or disposed of in landfills.
Windrow A large, elongated pile of composting
Yard trimmings, yard waste Leaves, grass clip-
pings, prunings, and other natural organic matter
discarded from yards and gardens.
Allen, Frank Edward. "As Recycling Surges, Market
for Materials is Slow to Develop." Wall Street
Journal January 17, 1993.
Apotheker, Steve. "Processing Mixed Wastes:
Relearning the Lessons of the Past." Resource
Recycling. (September 1993): 49-56.
Anderson, Peter, and John Strasma. "Owning and
Operating a MRF: Inherent Public and Private
Economic Issues." MSW Management. (May/June
Bailey, Jeff. "Fading Crisis Leaves Incinerators
Competing for Trash." Wall Street Journal August
Bemheisel, J. Frank, and Warren Shuros. "How to
Plan and Implement Successful Municipal Solid
Waste (MSW) Composting Projects." Composting
Frontiers. (Summer 1993): 18-26.
de Bertoldi, Marco. "MSW Composting Challenges
in Europe." BioCycle. (October 1993): 75-76.
Clumpner, Greg, and Starr Dehn. "The 'Non-
Economics' of Mandated Source Reduction and
Recycling Programs." MSW Management. (October
Cornell Waste Management Institute. MSW
Composting Fact Sheet Series, 1-7. 1993.
Epstein, E., R.L. Chaney, C. Henry, et.al. "Trace
elements in Municipal solid waste compost."
Biomass and Bioenergy. Vol. 3, Nos. 3-4, pp. 227-238,
Gillett, James W., "Issues in risk assessment of
compost from Municipal solid waste: occupational
health and safety, publichealth, and environmental
concerns." Biomass and Bioenergy. Vol. 3, Nos. 3-4,
Goldstein, Nora. "Adding Paper to the Mix."
BioCycle. (August 1992): 54-58.
Harrison, Ellen Z., and Tom L. Richard. "Municipal
solid waste composting: policy and regulation."
Biomass and Bioenergy, Vol. 3, Nos. 3-4, pp. 127-143,
van de Kamp, Maarten. "Farm Composters Play
Significant Management Role." BioCycle. (Novem-
ber 1992): 67-69.
Kashmanian, Richard M., and Alison C. Taylor.
"Costs of Composting Yard Wastes vs. Landfilling."
BioCycle. (October 1992): 60-63.
Minnesota Extension Service, University of Minne-
sota. MSW Composting, is it Right for Your Com-
The Municipal Waste Management Association and
The U.S. Conference of Mayors. "A Report to the
Nation on Recycling in America's Cities." 1992.
Rathje, William, and Cullen Murphy. Rubbish!: The
Archaeology of Garbage. HarperCollins. 1992.
Repa, Ed. "Landfill Tipping Fees 1992." Waste Age.
(November 1993) 35-38.
Richards, Bill. "Recycling in Seattle Sets National
Standard but is Hitting Snags." Wall Street Journal
August 3, 1993.
Schall, John. "Does the Hierarchy Make Sense?"
MSW Management. (Jan/Feb 193): 25-33.
Segall, Lori. "Source-Separated Organics Programs
in Europe." Resource Recycling. (July 1993): 27-35.
Shiralipour, Aziz, Dennis B. McConnell, and Wayne
H. Smith. "Usesand benefits of MSW compost: a
review and an assessment." Biomass and Bioenergy.
Vol. 3, Nos. 3-4, pp. 267-279, 1992.
Slivka, Donald C., Thomas A. McClure, Ann R. Buhr,
et.al. "Compost:United States supply and demand
potential." Biomass and Bioenergy. Vol. 3, Nos. 3-4,
Steuteville, Robert. "Recycling: the Price is Right."
BioCycle. (September 1993): 54-59.
Steuteville, Robert and Nora Goldstein. "The State of
Garbage in America." BioCycle. (May 1993) 42-50.
Steuteville, Nora Goldstein, and Kurt Crotz.
"The State of Garbage in America: Solid Waste
Legislation." (June 1993): 32-37
Tyler, Rod. "Diversification at the Compost Factory."
BioCycle. (August 1993): 50-51.
Williams, John F. "An Options Crisis in MSW." MSW
Management, (July/Aug 1993): 78-83.
The U.S. Conference of Mayors. U.S. Solid Waste
Facility Profiles: Volume II. National Composting
United States Environmental Protection Agency.
Characterization of municipal solid waste in the
United States: 1992 update. EPA/530-R-92-019.
United States Environmental Protection Agency.
Decision-Makers Guide to Solid Waste Management.
EPA/530-SW-89-072. November 1989.
Printed on recycled paper
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