What are biosolids?
Biosolids are mostly organic solids resulting from the treatment of wastewater that have undergone additional treatment to kill pathogens. During treatment, bacteria and other tiny organisms break sewage down into simpler, harmless organic matter. The organic matter combined with bacterial cell masses, settles out to form biosolids. This organic matter is rich in such nutrients as nitrogen and phosphorus and contain other supplementary nutrients, including potassium, sulfur, magnesium, calcium, copper and zinc. Biosolids have been approved by the U.S. Environmental Protection Agency (EPA) for land application as a fertilizer and soil amendment and for composted products.
Biosolids are recycled on farms and forests in all 50 states, and in most developed countries around the world.
What are the different kinds of biosolids?
The federal Clean Water Act Part 503 regulations identify two classes of pathogen reduction for biosolids:
Class B biosolids undergo a “Process to Significantly Reduce Pathogens” (PSRP). Digesters and other forms of treatment kill from 90 to 99.5 percent of the pathogens originally found in wastewater solids. This means that pathogens are reduced to levels that are well below those found in animal manures. As an added layer of public protection, additional best management practices (BMPs) are required at the site where biosolids are applied, such as buffers and restrictions on access immediately after application. The natural environment of sunlight and existing organisms in the soil break down remaining pathogens.
In Virginia, Class B biosolids are used as a soil amendment in agriculture and forestry and to reclaim barren or disturbed lands. Site permits from the Virginia Department of Environmental Quality (DEQ) are required for Class B biosolids use.
Class A biosolids undergo a “Process to Further Reduce Pathogens (PFRP).” Pathogens are reduced to basically non-detectable levels. Class A biosolids products can be used on home lawns and gardens, parks and golf courses, and other places where public contact is likely, without further regulation or site permits. Class A biosolids products include composted biosolids, lime pasteurized biosolids and fertilizer pellets. Class A biosolids products are sometimes ingredients in soil amendments, potting soils, and slow-release fertilizers available at lawn and garden centers.
Are there heavy metals in biosolids?
Biosolids contain trace amounts of heavy metals, or “trace elements,” as do natural soils, manures and commercial fertilizers. These trace elements enter the wastewater treatment plant from several sources. The EPA thoroughly studied the potential risks from these trace elements and set strict maximum levels in biosolids to protect public health and the environment. Because of required industrial pretreatment and the risk-based standards for biosolids recycling, the risks posed by trace elements in biosolids are minimal.
Many of the regulated elements in biosolids are beneficial in correct amounts. Chromium, copper, iron, manganese, selenium and zinc are micronutrients for plants, animals and humans (look at the contents of a multi-vitamin tablet). It is the presence of these micronutrients that accounts for the greater effectiveness of biosolids as fertilizer when compared to traditional chemical fertilizers.
Extensive studies to determine whether liquid biosolids could spread disease through the air were recently reported by researchers at the University of Arizona’s Department of Microbiology and Immunology, and supported by the National Science Foundation Water Quality Center. Their conclusion: “…aerosolized microorganisms were not detectable during land application of liquid class B biosolids…” Click here for a PDF Fact Sheet on this question.
Is Staph aureus transmitted by biosolids?
The latest research says no.
A study reported in 2003 by scientists at the University of Arizona in Tucson produced convincing evidence that Staph aureus is not present in biosolids. The report appeared in the October 2003 issue of the Journal Environmental Science and Technology. Click here for a PDF Fact Sheet on this question.
Can biosolids harm our streams and groundwater?
Federal and state regulations, agricultural best management practices and nature provide multiple layers of protection for our streams and groundwater. Studies also show that biosolids can help reduce runoff into our streams and leaching into groundwater.
Virginia regulates how biosolids are applied in order to prevent runoff into streams or leaching into groundwater. Studies have demonstrated that biosolids applied according to current EPA and Virginia standards pose no risk to the Commonwealth’s water. Click here for a PDF Fact Sheet on this question.
Who regulates the generation and land application of biosolids in Virginia and how can I be sure they protect my health and the environment?
The EPA and the Virginia Department of Environmental Quality (DEQ) enforce clearly defined regulations that are designed to protect human health and the environment. Virginia’s regulations also involve the Department of Conservation and Recreation (DCR), among others.
The comprehensive regulatory program that exists today, which includes federal, state and local components, is based on decades of research and is designed to protect public health and the environment. Click here for a PDF Fact Sheet on this question.
How do biosolids help soils and crops?
Biosolids enrich the soil with essential nutrients and add needed organic matter to the soil.
Biosolids contain many essential plant nutrients, including the primary macronutrients nitrogen, phosphorus, and to a lesser extent, potassium. Biosolids supply these needed elements to plants much like commercial fertilizer. Click here for a PDF Fact Sheet on this question.
Can biosolids be applied to forests?
The application of biosolids to forestland is recognized as an effective method of fertilization and soil conditioning. Biosolids enhance tree health, promote growth and can improve wildlife habitat. When best management practices (BMP) are used, research shows that biosolids can help protect water quality.
Pine forests in the Piedmont and upper Coastal Plains areas of Virginia are well suited to land application of biosolids, since most of these forests are located in nutrient deficient soils. Click here for a PDF Fact Sheet on this question.
How do other states and countries handle biosolids?
The recycling of biosolids is a widespread and accepted practice throughout the United States and the world.
According to the EPA, all 50 states have biosolids management programs. According to a United Nations report, the land application of biosolids is continuing to grow in Europe and the agricultural recycling of biosolids is in wide use throughout most western nations, including Canada, Australia and New Zealand. Click here for a PDF Fact Sheet on this question.
How do we know that biosolids are safe?
The management of biosolids to minimize environmental and health risks has been the focus of hundreds of university research studies conducted for many years. The results of this extensive research show that biosolids can be managed so that the risk of adverse effects to the environment or public health from land application of biosolids is extremely low.
In 2008, an Expert Panel created by the Virginia General Assembly concluded that that during its 18-month study it had “uncovered no evidence or literature verifying a causal link between biosolids and illness.” Click here for a PDF Fact Sheet on this question.
How much land is receiving biosolids in Virginia?
According to the Virginia Department of Environmental Quality, during 2006, approximately 263,000 dry tons of biosolids were applied to nearly 56,000 acres of permitted land application sites. There are 8.25 million acres of cropland and pastureland in Virginia, thus biosolids was used as fertilizer on less than seven-tenths of one percent of this area. In comparison, commercial fertilizer was used on more than 2.3 million acres and animal manure on more than 389,000 acres (2007 U.S. Department of Agriculture Census). Click here for a PDF Fact Sheet on this question.
How are biosolids protected from industrial chemicals?
Certain industries create wastewater that contains unacceptable levels of chemicals or other pollutants. By federal law, these industries must pre-treat their wastewater before sending it to the community wastewater treatment facility. Localities set additional local standards for pollutants allowed in industrial discharges to their wastewater treatment facilities. The plants issue permits to certain industries within their service area, require certain industries to treat their wastewater before sending it to sewers, require testing and monitoring of discharges and conduct inspections and enforcement actions.
Why do municipalities land apply biosolids?
A municipality will choose land application when it provides the best option for the environment, public health and the community. Biosolids recycle valuable nutrients to farms and forestlands, which help sustain family farms and conserve green space. Biosolids recycling is a cost-effective, sustainable alternative to land filling, incineration or other management options.
What other options do municipalities have for managing biosolids?
Other options include disposal in sludge incinerators and co-disposal with trash in landfills. Municipalities also have choices in the type of processes used to prepare biosolids for land application—like composting and drying. Biosolids processing and disposal is a major portion of a wastewater utility’s costs, approximately 20-30 percent of total operating cost, so treatment options are carefully examined. An emerging use of biosolids is for energy production. Technologies for this use, however, are embryonic, expensive and not well established.
Who pays for the cost of managing biosolids?
The treatment of wastewater and the production of biosolids are services provided by local government, which are funded by local citizens through user fees and taxes. The cost of the state’s biosolids program is paid by a combination of taxpayer funding and permit fees paid by land application companies.
Are nutrients found in biosolids contributing to the decline in the Chesapeake Bay?
Urban wastewater plants reclaim the nutrients from sewage, thereby preventing their discharge into Virginia streams and rivers. When applied to farmland, the nutrients in biosolids—primarily nitrogen and phosphorus—replace the nutrients from the commercial fertilizer farmers would otherwise use. When managed and applied correctly using best management practices, biosolids pose less risk to the environment than chemical fertilizers.
Are biosolids more harmful to the environment than chemical fertilizers?
There are pros and cons to all forms of plant nutrients used by farmers; the key is how they are managed. Farmers can take advantage of the slow-release properties of biosolids nutrients during the growing season—in step with crop requirements. Additionally, the land application of biosolids is subject to more regulatory oversight than the use of commercial fertilizer, and has specific benefits that are superior to chemical fertilizers.
Are biosolids more harmful to the environment than animal manure?
Most animal manures and biosolids are applied to Virginia farmland using nutrient management plans to minimize nutrient loss to the environment. Again, each have their advantages and disadvantages; the key is how they are managed. Typically, the application of animal manures is not subject to the same amount of regulation as biosolids, such as restrictive buffers for streams or wetlands.
Do we really know what’s in biosolids?
Scientists know a lot about what’s in biosolids and are learning more each year. The EPA conducted an extensive risk analysis of the possible pollutants in biosolids when it established safe limits for land application of biosolids.
Under federal and state regulations, each wastewater treatment plant must test the flow entering the wastewater plant to ensure it meets strict pretreatment limits. Biosolids resulting from wastewater treatment must also be tested to meet EPA standards. Biosolids do contain trace amounts of pollutants, which if they occurred in high concentrations, would be considered a human or environmental danger; however, this is true also for compounds found in our water, air and food. The presence of these compounds in minute quantities does not represent a risk to human health or the environment.
Why aren’t biosolids landfilled?
Many municipalities that are committed to recycling consider landfill disposal of biosolids a waste of valuable nutrients and soil amendments that could benefit farms. While landfilling is one option available to cities and counties, it can be one of the most expensive because of transportation costs and tipping fees for commercial landfills. For municipalities that have their own landfills, there are substantial costs for operating the facilities and acquiring and permitting new sites when the old ones are full.
How are land application contractors selected by municipal treatment plants?
Once a municipal treatment plant decides to land apply its biosolids, it typically proceeds with a competitive bidding process, beginning first with a request for proposal (RFP). Contractors submit applications, which are then reviewed based on characteristics and performance requirements represented in the RFP. Price is only one of the many options reviewed by a municipality before choosing a contractor.
What is sludge and how is it different from biosolids?
Only biosolids that meet federal and state requirements following treatment are land applied. Sludge, a term applied to the solids separated from the liquid portion of wastewater passing through a wastewater treatment plant, is NOT land applied on farms and forestland in Virginia. The term “biosolids” is applied to material that receives additional processing to make it suitable for recycling. During this treatment, bacteria and other tiny organisms break sewage down into simpler, harmless organic matter. The organic matter combined with bacterial cell masses, settles out to form biosolids. This organic matter is rich in such nutrients as nitrogen and phosphorus and contain other supplementary nutrients, including potassium, sulfur, magnesium, calcium, copper and zinc. Federal and state regulations establish the processes that the wastewater plant or other facility must implement to qualify for the production of biosolids.
Can people get sick from biosolids?
Substantial evidence from years of research and the widespread use of biosolids on farms supports the conclusion that humans do not get sick from the land application of biosolids. The National Academy of Sciences, in its 2002 review of current practices, public health concerns and regulatory standards, concluded that the use of biosolids in the production of crops presents “negligible risk” to humans, crop production and the environment.
Stories alleging a connection between biosolids and disease have appeared on the Internet, but the validity of these claims has not withstood scientific analysis. Scientists and public health officials have investigated such claims and, where credible data was available, could identify no verifiable connection between alleged disease and biosolids use.
In 2007 the Virginia Department of Health published a study by three respected epidemiologists, Health Effects of Biosolids Applied to Land: Available Scientific Evidence (Jenkins, Armstrong et al. 2007). This study represented an exhaustive review of the current scientific literature about biosolids and human health. The primary conclusions were as follows: “… there does not seem to be strong evidence of serious health risks when biosolids are managed and monitored appropriately. Human health allegations associated with biosolids usually lack evidence of biological absorption, medically determined human health effects, and/or do not meet the biological plausibility test.”
In 2008, an Expert Panel created by the Virginia General Assembly concluded that that during its 18-month study it had “uncovered no evidence or literature verifying a causal link between biosolids and illness.”
Why do biosolids smell and are the odors harmful?
Biosolids produced by different municipalities have their own distinctive odors due to the types of processing and handling practices. As with many organic materials, biosolids odor is caused by compounds containing sulfur and nitrogen, which are produced when proteins in biosolids break down. The biosolids from one facility may have a stronger odor than another. The odors, while sometimes offensive, are not harmful.
Who is conducting research on biosolids?
Too many organizations to mention—worldwide. Many organizations are conducting biosolids research in this region, including state universities in Virginia, Delaware, Maryland and Pennsylvania. Active research is supported through grants from the federal government and by non-profit groups and associations focused on wastewater treatment.
Will biosolids decrease my property value?
No. Farmers who use biosolids are benefiting from a more cost-effective fertilizer option, helping the productivity and profitability of their operation. The more profitable an operation, the more likely the land will stay green, open and productive, thereby increasing its potential value. Unproductive farms in Virginia are, in most cases, quickly sold off for subdivision development. Keeping farms profitable maintains a locality’s rural character.
How much land is receiving biosolids in Virginia?
According to the Virginia Department of Environmental Quality, during 2006, approximately 263,000 dry tons of biosolids were applied to nearly 56,000 acres of permitted land application sites. Learn more.