The U.S. Environmental Protection Agency (EPA), Water Environment Federation (WEF)
and Association of Metropolitan Sewerage Agencies all promote biosolids recycling
as an environmentally safe and cost-effective solution for managing wastewater
residuals. When conducted in accordance with strict state and federal regulations,
the practice benefits communities and supports environmental protection efforts
with an excellent source of safe, organic nutrients.
The benefits of responsible and safe biosolids recycling are many. EPA supports
biosolids recycling and encourages composting and land application of biosolids,
including advanced alkaline-stabilized, heat-treated, and pelletized biosolids,
as well as less highly processed liquid biosolids and biosolids cake. Among their
benefits, the use of biosolids can:
Improve crop production
Reduce soil erosion and protect
topsoil for recreational uses
Reclaim strip-mined lands
Improve crop production
of biosolids that meet strict quality criteria and application rates is a beneficial
use. It helps improve, replenish and maintain healthy soil by adding important
nutrients, boosting soil water-holding capacity and reducing topsoil runoff, all
of which serve to increase crop yields. According to EPA, about half of the biosolids
generated in the United States is beneficially recycled. Biosolids provide farmers
with about $100 per acre worth of organic fertilizer that includes many essential
nutrients not typically found in chemical fertilizers. Farmers use biosolids primarily
to reduce their dependency on chemical fertilizers.
in nitrogen and phosphorus, two elements essential for crop growth, biosolids
also contain micronutrients such as copper, boron, molybdenum, zinc and iron.
Lime-amended biosolids supply valuable lime to the fields. Replenishing farm topsoil
with biosolids promotes long-term productivity.
largest component of biosolids is organic matter. It works as a soil conditioner
to promote necessary bacterial activity, loosening clay and improving the consistency
of sandy soils. The improved texture of these treated soils promotes dense, healthy
root growth, allowing plants to take up nutrients better. This leads, in turn,
to higher crop productivity than is possible with equivalent amounts of chemical
Reducing Erosion, Protecting Water Quality
to EPA, both biosolids land application and composting can reduce soil erosion
and improve water quality. The organic matter in biosolids assists with binding
soil particles. The result is improved soil properties, including texture and
water-holding capacity, which enhances root growth and increases the drought resistance
Adding biosolids to soil also supplies organic nutrients that are released slowly to growing plants.
These organic forms of nutrients are less water-soluble and, therefore, less likely
to leach into groundwater or be carried away by streams and other surface waters.
Surface-applied biosolids are less likely to pollute than are animal manures or
Providing Topsoil for Recreational Uses
organic fertilizer, biosolids that meet EPA's Part 503 requirements (see "A
Plain English Guide to the EPA Part 503 Biosolids Rule") also provide nutrient-rich
materials for use on golf courses, sports fields, public parks and other recreational
areas. Biosolids composted with wood chips, sawdust or yard clippings provide
slow-release nitrogen and phosphorus and abundant organic matter. Biosolids compost
is commonly used by landscape designers, nurseries and soil blenders for building
lawns and turf, mulching plant beds, establishing new vegetation and general gardening.
have been used successfully to help reclaim disturbed land such as coal strip
mines, gravel pits, quarries, construction sites and landfills. Heavy equipment
can strip away topsoil and compact underlying soils. These and other industrial
activities can leave rock and subsoil exposed, contributing to runoff and water
pollution. Once soil is robbed of nutrients and organic matter, plant life cannot
replaces lost topsoil and improves soil fertility and stability, decreasing erosion.
Land reclamation projects typically use one-time or infrequent applications of
large quantities of biosolids to spur plant growth and provide a long-term supply
provide a balance of quick- and slow-release nutrients and organic matter, they
are preferable to chemical fertilizers for establishing vegetation. Quick-release
nutrients assure rapid, reliable seedling establishment. Slow-release nutrients
sustain vigorous plant growth that leads to a permanent plant community. The organic
matter helps to retain soil moisture, increase soil porosity and replace lost
or compacted soil.
increase forest productivity for certain tree species, promoting, for example,
the growth of hybrid poplars and enhancing the aesthetic value of Christmas trees.
Biosolids used on forestland can shorten pulpwood and lumber production cycles,
particularly in marginally productive soils. Because biosolids enhance vegetation
growth, wildlife populations benefit from more abundant under story vegetation
that give rise to more nutritious food supplies.
Conserving Landfill Space
to EPA, recycling biosolids can help to conserve landfill space, freeing up disposal
capacity for a community's solid wastes. Regulations adopted a decade ago have
increased the cost of developing and operating solid waste landfills and have
resulted in larger and more expensive regional facilities. This and often-frequent
community opposition based on land-use concerns have made siting new landfills
a more difficult process. Many communities prohibit the disposal of yard wastes
to conserve space. As an alternative, regulatory agencies encourage the beneficial
use of biosolids.
EPA estimates that beneficial use of biosolids will increase from 60 percent in 1998 to 66 percent
in 2005 and 70 percent in 2010. Of the biosolids sent for disposal in 1998, 17
percent went to surface disposal/landfills. EPA expects that percentage to decrease
to 13 percent in 2005 and 10 percent in 2010, with corresponding increases in
land application, advanced treatment and other beneficial uses.
recycling of biosolids through land application and other methods offers an environmentally
sound alternative to disposal and can conserve landfill space. In communities
where disposal costs have risen because of diminishing landfill capacity, biosolids
recycling can lower a community's waste disposal costs. These savings can be passed
on to communities in reduced taxes and lower utility bills. Some communities also
generate revenue from the sale of biosolids-derived compost, fertilizers and other