EPA acknowledges that Compost may be hazardous to you Health
United States Environmental Protection Agency Download from EPA site
http://www.epa.gov/owm/mtb/combioman.pdf
Survival and presence of primary pathogens in the product. But first look at the lead exposure hazards your
children are exposed to when you buy unlabelled sludge biosolids composted soil amendments at the
garden store. At some point your yard may be tested for lead and a hazmat crew will have to clean it up
under a permit as they do for leadbased paint flakes in the yard. This compost can not be disposed of in a p
part 503 permitted landfill.
Biosolids Technology Fact Sheet
Deadly Use of Composting for Biosolids Management
compost fact sheet follows abstract
The first part of EPA's biosolids composting fact sheet makes it sound like the perfect safe fertilizer for lawns,
parks, school yards. However, the last part of the fact sheet is a lot of confusing double talk. But it does tell
some of the truth. Except that Recycled Class A compost sold as an unlabelled fertilizer or soil amendment
may have, on average, 300 ppm of lead in it. EPA Office of Water claims 267 pounds of lead per acre is safe.
What you are not told by EPA's Office of Water.
Lead is even more dangerous to children than adults because:
- Babies and young children often put their hands and other objects in their mouths. These
objects can have lead dust on them.
- Children's growing bodies absorb more lead.
- Children's brains and nervous systems are more sensitive to the damaging effects of lead.
If not detected early, children with high levels of lead in their bodies can suffer from:
- Damage to the brain and nervous system
- Behavior and learning problems (such as hyperactivity)
- Slowed growth
- Hearing problems
- Headaches
- Children's brains and nervous systems are more sensitive to the damaging effects of lead.
Federal law requires that contractors provide lead information to residents before renovating a pre-1978
housing: Pre-Renovation Education Program (PRE) RENOVATORS have to give you a pamphlet titled
“Protect Your Family from Lead in Your Home”, before starting work
- A risk assessment tells you if there are any sources of serious lead exposure (such as peeling paint and
lead dust). It also tells you what actions to take to address these hazards.
- Have qualified professionals do the work. There are standards in place for certifying lead-based paint
professionals to ensure the work is done safely, reliably, and effectively.
Residential Lead-Based Paint Disclosure Program
- LANDLORDS have to disclose known information on lead-based paint and lead-based paint hazards
before leases take effect. Leases must include a disclosure form about lead-based paint.
- SELLERS have to disclose known information on lead-based paint and lead-based paint hazards
before selling a house. Sales contracts must include a disclosure form about lead-based paint. Buyers
have up to 10 days to check for lead hazards.
BUT WHAT ABOUT LEAD ON YOUR LAWN AND IN YOUR GARDEN FROM UNLABELED SOIL AMENDMENTS?
EPA statements in the body of the Compost fact sheet.
ADVANTAGES for municipalities
Biosolids composting has grown in popularity for the following reasons (WEF, 1995):
- Lack of availability of landfill space for solids disposal. [not exactly true -- but government does have
264 million acres where sludge - biosolds use is not allowed ]
- Composting economics are more favorable when landfill tipping fees escalate. [true]
- Emphasis on beneficial reuse at federal,state, and local levels. [true - no rules or health protection]
AND DISADVANTAGES for public health and the environment.
- Class A biosolids can be used in home gardens with public contact and no site restrictions.
- Odor production at the composting site.
- In addition to odors, other bioaerosols, such as pathogens, endotoxins, and various volatile organic
compounds, must also be controlled
- Potential environmental impacts may result from both composting operations and use of the compost
product
- Survival and presence of primary pathogens in the product.
- Composting is not a sterilization process and a properly composted product maintains an active
population of beneficial microorganisms that compete against the pathogenic members. Under some
conditions ,explosive regrowth of pathogenic microorganisms is possible.
- Dispersion of secondary pathogens such as Aspergillus fumigatus, particulate matter,other airborne
allergens
- While healthy individuals may not be affected, immunocompromised individuals may be at risk.
- The spores of A. fumigatus counts at composting facilities are high, and-- persons handling
composted biosolids being exposed to these spores is also high (Epstein, 1998).
- These organisms can potentially invade a normal, healthy human being and produce illness or
debilitation
- Lack of consistency in product quality with reference to metals, stability, and maturity.
- Dust and airborne particles from a composting operation may affect air quality. The impact to adjacent
areas may need to be mitigated and permitted to protect area ecology and water quality, run-off from
application sites must be controlled. The potential nitrogen and phosphorus rich run-off (or leachate)
can cause algal growth in surface water and render groundwater unfit for human consumption.
- Organic dust (such as pollen) is another nuisance that must be controlled at composting operations.
These contaminants are primarily a concern to workers at the composting facilities and are generally
not present in quantities that would cause reactions in most individuals that are not exposed outside
of the facilities.
- It should be noted that the most plant-available form of nitrogen in biosolids (ammonium ion (NH4 )) is converted
to nitrate (NO3 -) by the composting process.
- Improper use of biosolids can result in the contamination of water resources with leached nitrogen, because
nitrate is more mobile than ammonium, and is taken up less easily by plants
United States Environmental Protection Agency http://www.epa.gov/owm/mtb/combioman.pdf
download pdf forematted document
Biosolids Technology Fact
Sheet Use of Composting for Biosolids Management
DESCRIPTION
Composting is one of several methods for treating biosolids to create a marketable end product that is easy to handle,
store, and use. The end product is usually a Class A, humus-like material without detectable levels of pathogens that
can be applied as a soil conditioner and fertilizer to gardens, food and feed crops, and rangelands. This compost
provides large quantities of organic matter and nutrients (such as nitrogen and potassium) to the soil, improves soil
texture, and elevates soil cation exchange capacity (an indication of the soil’s ability to hold nutrients), all characteristics
of a good organic fertilizer.
Biosolids compost is safe to use and generally has a high degree of acceptability by the public. Thus, it competes well
with other bulk and bagged products available to homeowners, landscapers, farmers, and ranchers.
Three methods of composting wastewater residuals into biosolids are common. Each method involves mixing dewatered
wastewater solids with a bulking agent to provide carbon and increase porosity. The resulting mixture is piled or placed
in a vessel where microbial activity causes the temperature of the mixture to rise during the “active composting”
period. The specific temperatures that must be achieved and maintained for successful composting vary based on the
method and use of the end product. After active composting, the material is cured and distributed. The three commonly
employed composting methods are described in the following paragraphs. A fourth method (static pile) is not
recommended for composting wastewater solids based on a lack of operational control.
Aerated Static Pile - Dewatered cake is mechanically mixed with a bulking agent and stacked into long piles over a bed
of pipes through which air is transferred to the composting material.
After active composting, as the pile is starting to cool down, the material is moved into a curing pile.
Odor Filter
Finished
Compost
Blower
Airflow
Blanket of
Finished Compost
6-12 inches
Yard Trimmings,
Source-separated organics,
or Mixed MSW
Perforated
Aeration Pipe
4-8 Feet
Source: Hickman, 1999.
FIGURE 1 SCHEMATIC OF A STATIC-PILE FORCED-AIR COMPOSTING PROCESS
Source: Parsons, 2002.
FIGURE 2 WINDROW OPERATIONS ARE TURNED TO PROVIDE ADEQUATE AERATION FOR ACTIVE COMPOSTING
Source: Parsons, 2002.
FIGURE 3 TYPICAL COMPOSTING
VESSEL
The bulking agent is often reused in this composting method and may be screened before or after curing
so that it can be reused.
Windrow - Dewatered wastewater solids are mixed with bulking agent and piled in long rows. Because there is no piping
to supply air to the piles, they are mechanically turned to increase the amount of oxygen. This periodic mixing is
essential to move outer surfaces of material inward so they are subjected to the higher temperatures deeper in the
pile. A number of turning devices are available, including:
(1) drums and belts powered by agricultural equipment and pushed or pulled through the composting pile; and
(2) self-propelled models that straddle the composting pile. As with aerated static pile composting, the material is moved
into curing piles after active composting. Several rows may be laced into a larger pile for curing. Figure 2
shows a typical windrow operation.
In-Vessel - A mixture of dewatered wastewater solids and bulking agent is fed into a silo, tunnel, channel, or vessel.
Augers, conveyors, rams, or ther devices are used to aerate, mix, and move the product through the vessel to the
discharge point. Air is generally blown into the mixture. After active composting, the finished product is usually
stored in a pile for additional curing prior to distribution. A typical composting vessel is shown in Figure 3. This
technology is discussed in greater detail in the fact sheet entitled In-Vessel
Composting of Biosolids (EPA 832-F-00-061).
All three composting methods require the use of bulking agents, but the type of agent varies. Wood chips, saw dust, and
shredded tires are commonly used, but many other materials are suitable. The U.S Composting Council lists the following
materials as suitable for use as bulking agents:
• Agricultural by-products, such as manure and bedding from various animals, animal mortalities [dead animals], and
crop residues.
• Yard trimmings, including grass clippings, leaves, weeds, stumps, twigs, tree prunings, Christmas trees, and other
vegetative matter from land clearing activities.
• Food by-products, including damaged fruits and vegetables, coffee grounds, peanut hulls, egg shells, and fish
residues.
• Industrial by-products from wood processing, forestry, brewery and pharmaceutical operations. Paper goods,
paper mill residues, and biodegradable packaging materials are also used.
• Municipal solid waste. If municipal solid waste is used in compost, it is put through a mechanical separation process
prior to its use to remove non-biodegradable items such as glass, plastics and certain paper goods (USCC,
2000).
The length of time biosolids are composted at a specific temperature is important in determining the eventual use of the
compost end product. 40 CFR Part 503, Standards for the Use and Disposal of Sewage Sludge (Part 503) defines time
and temperature requirements for both Class A and Class B products (Table 1).
The production of a Class B product is not always economically justified since the product cannot be used without
restrictions and the additional expense to reach Class A requirements can be marginal. If the compost process conforms
with the time and temperature requirements to produce a Class A product and the maximum pollutant levels of Part
503 are met, the material is considered “Exceptional Quality” (EQ) biosolids.
If used in accordance with sound agronomic and horticultural practices, an EQ biosolids product can be sold in bags or
bulk and can be used in household gardens without additional regulatory controls. Class A and EQ biosolids
typically have greater marketing success than Class B biosolids. Control of industrial waste streams to
wastewater treatment plants (through pretreatment programs) greatly reduces the presence of metals in
pre-processed wastewater residuals, enabling compost to meet the stringent EQ standards of Part 503.
If the compost produced is Class B, it can be used at agronomic sites with no public contact, with additional site
restrictions.
Class A biosolids can be used in home gardens with public contact and no site restrictions. Consistent and predictable
product quality is a key factor affecting the marketability of compost (U.S. EPA, 1994).
Successful marketing depends on a consistent product quality.
Stability is an important characteristic of a good quality compost. Stability is defined as the level of biological activity in
the compost and is measured as oxygen uptake or carbon dioxide production.
Oxygen uptake rates of 50 to 80 mg/L are indicative of a stable product with minimal potential for self-heating, malodor
generation, or regrowth of pathogen populations. Stability is also indicated by temperature decline, ammonia
concentrations, chemical oxygen demand (COD), number of insect eggs, change in odor, and change
in redox potential (Haug, 1993).
Stable compost consumes little nitrogen and oxygen and generates little carbon dioxide.
Unstable compost consumes nitrogen and oxygen and generates heat, carbon dioxide, and water vapor. [bioaersols]
Therefore, when unstable compost is applied to soil, it removes nitrogen from the soil, causing a nitrogen deficiency that
can be detrimental to plant growth and survival. In addition, if not aerated and stored properly, unstable compost can
emit nuisance odors (Epstein, 1998, Garcia, 1991).
APPLICABILITY
The physical characteristics of most biosolids allow for their successful composting. However, many characteristics
(including moisture content, volatile solids content, carbon content, nitrogen content, and bulk density) will impact design
decisions for the composting method. Both digested and raw solids can be composted, but
TABLE 1 PART 503 TIME AND
TEMPERATURE REQUIREMENTS FOR
BIOSOLIDS COMPOSTING
Product Regulatory Requirements
Class A Aerated static pile or in-vessel: 55 C for at least 3 days
Windrow: 55 C for at least 15 days with 5 turns
Class B 40 C or higher for five days during which temperature exceed 55 C for at least four hours
Source: 40 CFR Part 503.
some degree of digestion (or similar stabilization) is desirable to reduce the potential for generation of foul odors from
the composting operation. This is particularly important for aerated static pile and windrow operations. Carbon and
nitrogen content of the wastewater solids must be balanced against that of the bulking agent to achieve a suitable
carbon to nitrogen ratio of between 25 and 35 parts carbon to one part nitrogen.
Site characteristics make composting more suitable for some wastewater treatment plants than others.
An adequate buffer zone from neighboring residents is desirable to reduce the potential for nuisance complaints. In
urban and suburban settings, invessel technology may be more suitable than other composting technologies because
the in-vessel method allows for containment and treatment of air to remove odors before release. The requirement
for a relatively small amount of land also increases the applicability of in-vessel composting in these settings.
Another important consideration before selecting the technology to be used for composting is the availability of
adequate and suitable manpower. Composting is typically labor-intensive for the following reasons:
• Bulking agents must be added.
• Turning, monitoring, or process control is necessary.
• Feed and finished material(s) must be moved with mechanical equipment.
• Storage piles must be maintained for curing and distribution.
• Bulking agents recovery adds another step.
Finally, proximity to the markets for the resulting compost is desirable, although the usefulness of the final product in
home gardening and commercial operations generally makes the material marketable in urban as well as rural areas.
This is especially true for good quality material that does not emit foul odors.
ADVANTAGES AND DISADVANTAGES
Biosolids composting has grown in popularity for the following reasons (WEF, 1995):
• Lack of availability of landfill space for solids disposal.
• Composting economics are more favorable when landfill tipping fees escalate.
• Emphasis on beneficial reuse at federal, state, and local levels.
• Ease of storage, handling, and use of composted product.
• Addition of biosolids compost to soil increases the soil’s phosphorus, potassium, nitrogen, and organic carbon content.
Composted biosolids can also be used in various land applications. Compost mixed with appropriate additives creates a
material useful in wetland and mine land restoration. The high organic matter content and low nitrogen content
common in compost provides a strong organic substrate that mimics wetland soils, prevents overloading of nitrogen, and
adsorbs ammonium to prevent transport to adjacent surface waters (Peot, 1998). Compost amended strip-mine spoils
produce a sustainable cover of appropriate grasses, in contrast to inorganic-only amendments which seldom provide
such a good or sustainable cover (Sopper, 1993).
Compost-enriched soil can also help suppress diseases and ward off pests. These beneficial uses of compost can help
growers save money, reduce use of pesticides, and conserve natural resources. [according to EPA, biosolids is a
better food for creating lethal bacteria than commercial laboratory grade soy by almost two to one]
Compost also plays a role in bioremediation of hazardous sites and pollution prevention. Compost has proven effective
in degrading or altering many types of contaminants, such as wood-preservatives, solvents, heavy metals, pesticides,
petroleum products, and explosives. Some municipalities are using compost to filter stormwater runoff before it
is discharged to remove hazardous chemicals picked up when stormwater flows over surfaces such as roads, parking
lots, and lawns. Additional Source: Parsons, 2002.
FIGURE 4 ODOR CONTROL EQUIPMENT
CAN BE A SUBSTANTIAL PART OF
CAPITAL INVESTMENT
uses for compost include soil mulch for erosion control, silviculture crop establishment, and sod production media (U.S.
EPA, 1997a).
Limitations of biosolids composting may include:
• Odor production at the composting site.
• Survival and presence of primary pathogens in the product.
• Dispersion of secondary pathogens such as Aspergillus fumigatus, particulate matter,other airborne
allergens.
• Lack of consistency in product quality with reference to metals, stability, and maturity.
Odors from a composting operation can be a nuisance and a potential irritant. Offensive odors from composting sites
are the primary source of public opposition to composting and have led to the closing of several otherwise well-operated
composting facilities. Although research shows that biosolids odors may not pose a health threat, odors from processing
facilities have decreased public support for biosolids recycling programs (Toffey, 1999).
Many experts in the field of biosolids recycling believe that biosolids generating and processing facilities have an
ethical responsibility to control odors and protect nearby residents from exposure to malodor.
Composting odors are caused by ammonia, amine, sulfur-based compounds, fatty acids, aromatics, and hydrocarbons
(such as terpenes) from the wood products used as bulking agents (Walker, 1992). [and hydrogen sulfide producing
bacteria]
A properly designed composting plant, such as the one shown in Figure 4, operated at a high positive redox
potential (highly aerobic) will reduce, but not necessarily eliminate, odors and odor causing compounds during the first
10 to 14 days of the process (Epstein, 1998). Control of odors is addressed in further detail in the fact sheet entitled
Odor Management in Biosolids Management (EPA 832-F-00-067).
In addition to odors, other bioaerosols, such as pathogens, endotoxins, and various volatile organic
compounds, must also be controlled. Biofilters are often used to control odors, but the biofilters themselves can
give off bioaerosols.
Pathogens, such as bacteria, viruses, and parasites (helminth and protozoa), are present in untreated wastewater
residuals. These organisms can potentially invade a normal, healthy human being and produce illness or debilitation.
Composting reduces bacterial and viral pathogens to non-detectable levels [viable, but non-culturable
(VBNC)] if the temperature of the compost is maintained at greater than 55 C for 15 days or more. Additionally, it has
been demonstrated that viruses and helminth ova do not regrow after thermal inactivation (Hay, 1996). [Reserved for
rehydrated viruses]
[Division of airbone bacteria]
Regrowth of Salmonella sp. in composted biosolids is a concern, although research shows that salmonellae
reach a quick peak during regrowth, then die off.
Composting is not a sterilization process and a properly composted product maintains an active population of beneficial
microorganisms that compete against the pathogenic members. Under some conditions, explosive regrowth of
pathogenic microorganisms is possible.
A stabilized product with strict control of post-composting handling and addition of amendments coupled with four to six
weeks of storage will mitigate Salmonella regrowth (Hay, 1996).
Compost workers may be exposed to a common fungus known as Aspergillus fumigatus, endotoxins,
or other allergens. A. fumigatus is common in decaying organic matter and soil. Inhalation of its
airborne spores causes skin rashes and burning eyes. [part 503 does not cover A. fumigatus fungi which
can infect the lungs, etc.]
While healthy individuals may not be affected, immunocompromised individuals may be at risk. The spores of A.
fumigatus are ubiquitous and the low risk of exposure is not a significant health concern. However, spore counts at
composting facilities are high, and the risk of operators and persons handling composted biosolids being
exposed to these spores is also high (Epstein, 1998).
Inhalation of spores, particulates, and other matter can be reduced or prevented by:
• Wearing masks and other protective devices.
• Equipping front end loaders with filters or air conditioners.
• Thoroughly ventilating composting halls.
• Installing biofilters or other odor scrubbing systems in composting halls (Epstein 1998).
Organic dust (such as pollen) is another nuisance that must be controlled at composting operations.
These contaminants are primarily a concern to workers at the composting facilities and are
generally not present in quantities that would cause reactions in most individuals that are not exposed
outside of the facilities.
Environmental Impact
Potential environmental impacts may result from both composting operations and use of the compost product.
Composting Process
Dust and airborne particles from a composting operation may affect air quality. The impact to adjacent areas may need
to be mitigated and permitted.
To protect area ecology and water quality, run-off from application [beneficial use] sites must be controlled. The
potential nitrogen and phosphorus rich run-off (or leachate) can cause algal growth in surface water and render
groundwater unfit for human consumption. [This restriction is for a 503.24 surface disposal landfill site]
Land Application of Compost Products
Excess nitrogen is detrimental to soil, plants, and water, so care must be taken when choosing application sites,
selecting plant/crop types, and calculating the agronomic rate for biosolids land application. It should be noted that the
most plant-available form of nitrogen in biosolids (ammonium ion (NH4 )) is converted to nitrate (NO3 -) by the
composting process.
Improper use of biosolids can result in the contamination of water resources with leached nitrogen, because nitrate is
more mobile than ammonium, and is taken up less easily by plants. However, applying compost in accordance with the
Part 503 Regulations [its not regulated] poses little risk to the environment or public health (Fermante, 1997).
In fact, the use of compost can have a positive impact on the environment in addition to the soil improving characteristics
previously discussed. Reduced dependence on inorganic fertilizers [less plant uptake and more mobile?] can
significantly decrease nitrate contamination of ground and surface waters often associated with use of inorganic
fertilizers.
PERFORMANCE
Composting is a viable, beneficial option in biosolids management. It is a proven method for pathogen reduction and
results in a valuable product. According to a 1998 survey in Biocycle, The Journal of Composting and Recycling, 274
biosolids composting facilities were operating in the United States (Goldstein, 1999). Nearly 50 additional facilities were
in various stages of planning, design, and construction. A large number of these facilities (over 40 percent) use the
aerated static pile composting method.
Since 1984, EPA has encouraged the beneficial use of wastewater residuals through formal policy statements. The
implementation of Part 503 enhanced the acceptance of biosolids as a resource by standardizing metal and pathogen
concentrations.
Moreover, Part 503 officially identifies composting as a method to control pathogens and reduce vector attraction.
Discussions of the specific performance factors of the three primary composting methods are provided below.
Aerated static pile systems are adaptable and flexible to bulking agents and production rates. Aerated static pile is
mechanically simple, thus with lower maintenance than other cost method.
Conversely, this configuration can be labor intensive and may produce nuisance odors and dust. Cover, negative
aeration, chemically scrubbing, or use of a well-maintained biofilter may be required to minimize off-site odor migration.
The popularity of the aerated static pile method is based on the ease of design and operation and lower capital costs
associated with facility construction. Selection of an appropriate method requires an assessment of the physical facility,
process considerations, and operation and maintenance costs (WEF, 1995).
Windrow composting is adaptable, flexible and relatively mechanically simple. However, the windrow configuration
requires a large area and can result in release of malodor, dust, and other airborne particles to the environment during
natural processing, ventilation, and windrow turning.
In-vessel systems are less adaptable and flexible compared with aerated static pile and windrow systems. However, in-
vessel composting requires a smaller area. Because the reactor is completely enclosed, the potential for odor and the
need for controls is increased. Due to the greater complexity of in-vessel mechanical systems, trouble can be
encountered meeting peak flows, breakdowns are more frequent, and repairs are more difficult and costly. Failure of
aeration devices, under- designed aeration systems, or lack of a back-up aeration method may cause large quantities of
product to become anaerobic, and therefore, unacceptable.
Often the compost residence time in in-vessel composting systems is inadequate to produce a stable product,
particularly where the depth of the composting mass is great, (e.g., more than 3 m [10 feet]) and mixing does not occur.
In addition, bridging sometimes occurs within these systems.
Finally, depending upon the configuration and direction of air flow, the worker environment can be very hostile.
However, in-vessel composting requires a smaller area and generates relatively little dust outside the facility.
Table 2 compares the three methods and highlights key features of each.
COSTS
The capital costs of aerated static pile or windrow configuration may be lower than in-vessel composting configurations,
but costs increase markedly when cover is required to control odors. More highly mechanized in-vessel systems are
often more costly to construct, but tend to be less labor intensive. On the other hand, in-vessel systems tend to be less
flexible in their ability to adapt to changing properties of biosolids and bulking agent feedstocks.
Capital costs of in-vessel systems range from
$33,000 to $83,000 per dry metric ton ($30,000 to
$75,000 per dry ton) per day processing capacity.
A typical aerated static pile facility costs
approximately $33,000 per dry metric ton ($30,000
per dry ton) per day of processing capacity
(Harkness, 1994; U.S. EPA, 1989).
Typical operation and maintenance (O&M) costs
for in-vessel systems range from $150 per dry ton
per day to greater than $200 per dry ton per day.
Aerated static pile O&M costs average $150 per
dry ton per day (Harkness, 1994; U.S. EPA, 1989).
Costs for windrow systems fall between the costs
for in-vessel and aerated static pile. The selling
price for compost ranges from $5 to $10 per cubic
yard or $10 to $20 per ton. Some facilities allow
landscapers and homeowners to pick up compost
for little or no charge.
REFERENCES
Other Related Fact Sheets
In-Vessel Composting of Biosolids
EPA 832-F-00-061
September 2000
Odor Management in Biosolids Management
EPA 832-F-00-067
September 2000
Centrifuge Thickening and Dewatering
EPA 832-F-00-053
September 2000
Belt Filter Press
EPA 832-F-00-057
September 2000
Other EPA Fact Sheets can be found at the
following web address:
http://www.epa.gov/owm/mtb/mtbfact.htm
1. 40 Code of Federal Regulations, Part 503,
Standards for the Use and Disposal of
Sewage Sludge.
2. Benedict, A.H., E. Epstein, and J. Alpert,
1987. Composting Municipal Sludge: A
T e c h n o l o g y E v a l u a t i o n .
EPA/600/2-87/021, Water Engineering
Research Laboratory, Office of Research
and Development, U.S. Environmental
Protection Agency, Cincinnati, Ohio.
3. Burkhardt, J.W., W.M. Miller, and M.
Azad, 1993. “Biosolids Application to
TABLE 2 COMPARISON OF COMPOSTING METHODS
Aerated Static Pile Windrow In-Vessel
Highly affected by weather (can
be lessened by covering, but at
increased cost)
Highly affected by weather (can
be lessened by covering, but at
increased cost)
Only slightly affected by weather
Extensive operating history both
small and large scale
Proven technology on small scale Relatively short operating history
compared to other methods
Large volume of bulking agent
required, leading to large volume
of material to handle at each
stage (including final distribution)
Large volume of bulking agent
required, leading to large volume
of material to handle at each
stage (including final distribution)
High biosolids to bulking agent
ratio so less volume of material to
handle at each stage
Adaptable to changes in biosolids
and bulking agent characteristics
Adaptable to changes in biosolids
and bulking agent characteristics
Sensitive to changes in
characteristics of biosolids and
bulking agents
Wide-ranging capital cost Low capital costs High capital costs
Moderate labor requirements Labor intensive Not labor intensive
Large land area required Large land area required Small land area adequate
Large volumes of air to be treated
for odor control
High potential for odor generation
during turning; difficult to
capture/contain air for treatment
Small volume of process air that is
more easily captured for treatment
Moderately dependent on
mechanical equipment
Minimally dependent on
mechanical equipment
Highly dependent on mechanical
equipment
Moderate energy requirement Low energy requirements Moderate energy requirement
Source: Parsons, 2002.
Rangelands.” Water Environment and
Technology, 5(5):68-71.
4. Epstein, E., 1998. Design and Operations
of Composting Facilities: Public Health
Aspect. http://www.rdptech.com/tch15.htm,
accessed 2002.
5. Fermante, Jon V. and Meggan Janes, 1997.
“Managing Biosolids Through
Composting.” Pollution Engineering,
29(13):40-44.
6. Garcia, C., T. Hernandez, and F. Costa,
1991. “The Influence of Composting on the
Fertilizing Value of an Aerobic Sewage
Sludge.” Plant and Soil, 136:269-272.
7. Harkness, G.E, C.C. Reed, C.J. Voss, C.I.
Kunihiro, 1994. “Composting in the Magic
Kingdom.” Water Environment and
Technology, 6(8):64-67.
8. Haug, R. T., 1993. The Practical Handbook
of Compost Engineering. Lewis Publishers,
Boca Raton, FL
9. Hay, J.C., 1996. “Pathogen Destruction and
Biosolids Composting.” BioCycle, Journal
of Waste Recycling, 37(6):67-72.
10. Hickman Jr., H. Lanier, 1999. The
Principles of Integrated Solid Waste
Management. American Academy of
Environmental Engineers, Annapolis, MD.
11. Millner, P.D., et al., 1994. "Bioaerosols
Associated with Composting Facilities.”
Compost Science and Utilization 2:No.4,
Autumn 1994.
14. Nevada Division of Environmental
Protection, 1995. Program Statement:
Biosolids Reuse and Domestic Sewage
Sludge Disposal. Bureau of Water Pollution
Control. Ver. 2.1.
15. Parsons, 2002. Various materials.
16. Peot, C., 1998. “Compost Use in Wetland
Restoration: Design for Success.”
published in proceedings of The 12th
Annual Residuals and Biosolids
Management Conference. Water
Environment Federation, Alexandria,
Virginia.
17. Roe, N.E., P.J. Stoffella, and D. Graetz,
1997. “Composts from Various Municipal
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