BIOSOLIDS PRODUCTS ARE USED BY FARMERS, HORTICULTURISTS, LANDSCAPERS AND HOMEOWNERS TO HELP CROPS, FLOWERS, SHRUBS AND GRASS GROW BETTER.

What are biosolids?
Biosolids are the mostly organic solids resulting from the treatment of wastewater. They are rich in nutrients such as nitrogen and phosphorus and contain other supplementary nutrients such as potassium, sulfur, magnesium, calcium, copper, and zinc.

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What is wastewater?
Wastewater comes from home kitchens, bathrooms, and laundries as well as process and washwater from industries and businesses. It is treated in septic systems or at wastewater treatment facilities.

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What is in wastewater?
Wastewater is mostly water (about 99.5%). Less than 1/2% is suspended solids which must be removed so the water can be returned safely to the environment. The suspended solids are either inorganic (sand, grit, nutrients such as nitrogen and phosphorus, salts, and metals) or organic (primarily waste products of animal or vegetable origin). Wastewater also contains living organisms such as bacteria, some of which come from the human digestive system.

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Why do we have wastewater treatment?
Wastewater treatment is necessary to protect the public health and environment. Discharging raw sewage into lakes and streams harms those environments and can spread disease. In lakes and streams, native bacteria, algae, and other microscopic organisms (microbes) use the waste as food. These microbes eat and reproduce using the available oxygen dissolved in the water. If too much waste enters a waterbody, the microbes will use too much of the available oxygen needed by fish and other aquatic life.

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How does wastewater treatment work?
Wastewater treatment plants use the same biological and physical processes by which water is cleaned in nature. The steps to clean water include industrial pre-treatment, preliminary treatment, primary treatment, and secondary treatment.

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What is industrial pre-treatment?
Certain industries create wastewater that contains unacceptable levels of chemicals or metals. These industries must pre-treat their wastewater before sending it to the community wastewater treatment facility. Pretreatment regulations were developed under the Clean Water Act. These regulations ban the discharge of any toxic substance that might...

• hinder the wastewater treatment process
• pass through the wastewater treatment plant and contaminate the plant’s receiving waters, or
• concentrate in the biosolids.
  

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What types of industries are subject to pre-treatment requirements?
The EPA has specific pretreatment regulations for 29 industrial categories ranging from textiles and chemical manufacturing to leather tanning and electronics.

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Who enforces pre-treatment regulations?
State and local governments usually enforce pretreatment programs. Permits are generally required by federal or state regulatory agencies before industrial discharges to the community treatment facility are allowed. Reporting and monitoring requirements are also usually set by state and local regulatory agencies.

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How does pre-treatment work?
Industries use physical, chemical, or biological methods to pretreat their wastewater. Examples of each are as follows:

• Physical: filters, sedimentation tanks, flotation;
• Chemical: bind contaminants to particles which are removed by physical methods, or destroy the contaminants;
• Biological: use microbes to consume organic material or nutrients.

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What is Preliminary Treatment?
Preliminary treatment is the initial physical screening of wastewater at a wastewater treatment facility. This process removes debris such as rags, wood, and plastics.

What is Primary Treatment?
At a wastewater treatment facility, after grit and debris are removed, wastewater flows into a large sedimentation tank or "clarifier." Here wastewater is held relatively motionless for several hours. Solids settle and collect on the bottom; these are called "primary solids" or "primary sludge." Grease and oils float to the top and are removed for either further treatment or disposal at a landfill. Preliminary and Primary Treatment remove about 50-65% of the solids in wastewater.

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What is Secondary Treatment?
Secondary treatment is a biological process which relies on the same microbes that clean natural waterways. After primary treatment, wastewater is held in another large tank in which microbes feed on the suspended and dissolved solids in the wastewater. Treatment plant operators carefully monitor and control the temperature, pH (acidity), and amount of oxygen in the wastewater to ensure the health of the working microbes. Gradually, older microbes, which have eaten their fill, die and settle to the bottom. They take with them the suspended and dissolved solids that they consumed. The nearly pure water flows out of the top of the secondary treatment tank and is disinfected prior to being released into a river, ocean, or groundwater. The collected "secondary solids" are mixed with the "primary solids" and treated and tested for recycling. Secondary Treatment removes about 85% of the remaining suspended solids and nutrients.

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Where do the biosolids come from?
The solids or "sludge" collected from the primary and secondary treatments are mixed together and undergo further treatment. Most often, these combined solids are "dewatered" to make a more manageable, semi-solid material. Dewatering usually involves centrifuges, vacuum filters, drying beds, or presses that remove excess water. The solids are also "stabilized" by some form of digestion (aerobic or anaerobic) and/or composting, or some other treatment. There are stringent federal guidelines (the federal "Part 503" regulations of the Clean Water Act) which identify approved treatment processes. These stabilization processes reduce pathogens (microscopic organisms that can cause disease in humans) and odors. They also make the solids less attractive to "vectors" (animals that can carry pathogens, such as flies). Only once they have been through these treatment and testing procedures can "sludges" be called "biosolids" and used as fertilizers and soil amendments.

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What about pathogens in biosolids?
Pathogens are microscopic organisms that can cause disease in humans. They are found in wastewater and the solids removed from wastewater. Required biosolids treatment processes reduce the levels of pathogens to make biosolids recycling safe. As noted by the National Research Council of the National Academy of Sciences, there have been no reported outbreaks of infectious disease associated with exposure to properly treated and utilized biosolids.

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Are there differences in the levels of pathogen
reduction?
What is "Class A" and "Class B?"
The federal Clean Water Act Part 503 regulations identify two classes of pathogen reduction:

Class A: Class A biosolids undergo a "Process to Further Reduce Pathogens (PFRP)." Pathogens are reduced to a level similar to the native soil and environment. Class A biosolids products can be used on home lawns and gardens, parks and golf courses, and other places where public contact is likely. Class A biosolids products available in New England 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.

Class B: Class B biosolids undergo a "Process to Significantly Reduce Pathogens (PSRP)." This means that while pathogens are significantly reduced to levels which are often below those found in animal manures, additional best management practices ("BMPs") are required at the site where they are used. In New England, Class B biosolids are used in bulk as fertilizers in agriculture and forestry and to reclaim barren lands. Site permits are required for Class B biosolids use.

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What type of monitoring is undertaken during the wastewater treatment process?
Wastewater treatment facilities constantly monitor incoming wastewater, internal flows, outgoing clean water ("effluent"), and biosolids to properly control the treatment process. Each facility must document compliance with exhaustive requirements of the federal Clean Water Act, including the "Part 503" regulations. Monitoring requirements include...

• what samples must be collected at various locations in the facility,
• the frequency of sampling, and
• the frequency of reporting to regulatory agencies.
  

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What types of testing are undertaken?
There are several types of testing:

• Physical examination: color, odor, turbidity, temperature;
• Biological examination: testing for certain indicator organisms;
• Chemical examination: oxygen levels, pH, total solids, volatile solids, nutrients, and priority pollutants. Depending upon the certification of the treatment plant’s laboratory, testing may be done in-house or by other laboratories.
  

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Is biosolids recycling safe? How do we know?
Yes! Federal and state standards and management practices for biosolids recycling were developed from a detailed scientific risk assessment ever completed by the U.S. Environmental Protection Agency (EPA). Input included research and expertise from the U.S. Department of Agriculture and premier universities including the Universities of Arizona, California, Colorado, Florida, Maine, Michigan, Massachusetts, Minnesota, New Hampshire, Oregon, Vermont, Washington, and Colorado State, Ohio State, Penn State, and Cornell Universities.

The research strongly supports the finding of the U.S. Environmental Protection Agency (EPA) that
"In fact, in all the years that properly treated biosolids have been applied to the land, we have been unable to find one documented case of illness or disease that resulted" (Martha Prothro, former Deputy Assistant Administrator for Water, EPA, statement made September 1, 1992).

The National Research Council of the National Academy of Sciences stated in an exhaustive 1996 review of biosolids recycling:

"While no disposal or reuse option can guarantee complete safety, the use of these materials in the production of crops for human consumption, when practiced in accordance with existing federal guidelines and regulations, presents negligible risk to the consumer, to crop production, and to the environment." (National Research Council, 1996. See www.nap.edu/readingroom/books/sludge/index.html.)

For more about the EPA risk assessment, contact the NEBRA office or EPA at www.epa.gov/owm/ or the Water Environment Federation at www.wef.org.

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What about heavy metals?
Biosolids contain trace amounts of "heavy metals," as do natural soils, manures, and commercial fertilizers. These trace metals come from human wastes, household plumbing systems, household products, businesses and industries. The U.S. Environmental Protection Agency (EPA) thoroughly studied the potential risks from these trace metals and set strict maximum levels in biosolids to ensure protection of public health and the environment. Because of required industrial pretreatment and the risk-based standards for biosolids recycling, the risks posed by trace metals in biosolids are minimal.

Note that many of the regulated metals in biosolids are beneficial in correct amounts. Chromium, copper, iron, manganese, selenium, and zinc are micronutrients for plants, animals, and humans (look what’s in a multi-vitamin and mineral tablet!). It is the presence of these micronutrients that accounts for the greater effectiveness of biosolids as fertilizer when compared to traditional chemical fertilizers.

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What about organic chemical compounds?
There are many chemicals used in society today. Many can be found in small amounts in wastewater. But, because wastewater treatment includes many different physical, chemical, and biological processes that break down chemicals, biosolids contain few chemicals of concern. The 1989 National Sewage Sludge Survey conducted by the U.S. Environmental Protection Agency (EPA) found that chemicals of concern are generally either not present in biosolids or are found only in very low concentrations. The EPA risk assessment included such chemicals and determined that, at the levels found in biosolids, they pose negligible risk to public health and the environment.

There are two groups of organic chemical compounds that are of greatest public concern: PCBs and dioxins. Both are banned from use, but are, unfortunately, present in trace amounts throughout the environment. Surveys of biosolids have shown that while these compounds are sometimes found in biosolids, they are at levels similar to background levels or levels found in other commonly used products. For instance, surveys of New England biosolids products have found that dioxin levels are below the conservative risk-based standard of 27 parts per trillion established by the State of Maine.

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Will the use of biosolids adversely impact nearby surface waters and/or groundwater?
No. Properly treated and properly managed biosolids products do not have a negative impact on surface water or groundwater quality. As with any fertilizer or soil amendment, best management practices must be followed to prevent impacts via surface water runoff or via leaching to groundwater. By law, biosolids recycling programs must follow such best management practices; the same is not true for the use of manures and chemical fertilizers.

The fact is, numerous biosolids recycling programs have caused documented improvements in the quality of surrounding water bodies. How? By enriching soils and helping vegetation grow more vigorously. This results in reduced soil erosion and stabilization of on-site contaminants that had previously contributed to stream and groundwater pollution.

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Will the value of my property be adversely
impacted if biosolids are used in my neighborhood?
No. Studies have shown that biosolids are beneficial. Indeed, by using biosolids, farmers and other landowners are managing the nutrients and processes on their properties more carefully and responsibly than the average landowner. In addition, those who use biosolids may be benefiting from a more efficient fertilizer option, thus helping their farm fields or other open lands be more profitable. The more profitable their operations are, the more likely it is that farmers and other landowners will keep their properties green and open for the neighborhood to enjoy.

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What about odors?
Some biosolids products can create unpleasant odors, but many do not. Most Class A biosolids products (e.g. compost, fertilizer pellets) are basically odor free or have a slight earthy smell. Some bulk Class B biosolids products have odors similar to animal manures used to fertilize farm fields. As with manures, when bulk Class B biosolids are land applied, some odors are possible, but temporary. State biosolids regulations require farmers and biosolids managers to have "good neighbor" policies that reduce the possible impacts of odors associated with biosolids land application programs.

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How can I know that biosolids are being properly
managed?
State regulations allow for public input in Class B biosolids recycling projects. Most wastewater treatment facilities are public and share their testing and process information willingly. You can learn more about biosolids recycling by contacting you local wastewater or biosolids treatment facility. You can visit biosolids recycling operations and get copies of permits and other documents. State regulators and wastewater treatment personnel are glad to share information about biosolids production and recycling--just ask. If you are unsure who to call, contact NEBRA for referrals.

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What other wastewater residuals are recycled in
New England?
Some businesses and industries use large amounts of water during the manufacturing process. Pulp and paper mills are an example. This wastewater is cleaned at the mill’s private wastewater treatment facility using the same processes as a community wastewater treatment facility. The solids removed are mostly pieces of wood fiber too short to become part of paper (thus, they are sometimes called "short paper fibers" or SPF). After testing, these pulp and paper mill residuals can be useful soil amendments. They are rich in organic matter and can have some or little nitrogen and phosphorus. They help build the organic matter in soils, making soils lighter, more water absorbent, and more resistant to erosion.

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What options are available for biosolids and other
residuals?
Recycling, incineration, or landfill disposal. All three options have costs and risks associated with them. Biosolids recycling provides a cost-effective and environmentally sound option and is the option of choice according to the U.S. Environmental Protection Agency (EPA) and state environmental regulators.

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What are some of the costs, benefits, and risks
associated with incineration?
Burning biosolids or other residuals ("incineration") significantly reduces their volume and weight, producing an ash. This ash is generally landfilled because it contains high levels of trace metals. Incinerators require significant capital investment and have relatively high operational costs. Because biosolids are mostly water (70% - 98%), the energy costs to burn them can be significant, although some energy can be recovered from burning the solid portion. Expensive and sophisticated air pollution control systems are needed to remove particulates and gases from incinerator smokestacks. Incineration of biosolids does not take advantage of the nutrients and soil-building qualities in biosolids/residuals. Incineration has been used extensively in southern New England for biosolids disposal where population is dense and agricultural activities are less common. About 50% of New England’s biosolids are incinerated.

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What are some of the costs, benefits, and risks associated with landfilling biosolids?
Modern landfills are complex and costly facilities. They must be carefully engineered and monitored to ensure protection of nearby groundwater and surface water. New England’s long-term landfill capacity is limited. Engineering requirements and siting considerations make the construction of new landfills costly and difficult. Biosolids and other organic wastes in a landfill require special handling and monitoring and may be either beneficial or detrimental. Landfilling of biosolids does not take advantage of the nutrients and soil-building qualities in biosolids/residuals and uses up valuable landfill space. Currently, about 20% of New England’s biosolids are landfilled.

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Is biosolids recycling the right thing to do?
Yes!

• Biosolids recycling returns nutrients and organic matter to soils.
• Biosolids recycling avoids the need for more costly landfill space or incinerators.
• Biosolids products are efficient fertilizers and soil amendments that build soils, restore barren lands, and help keep New England landscapes open and growing.
• Biosolids recycling has been proven safe and beneficial through decades of scientific study and peer review.