Biosolids Program
Regulation and Beneficial Use of Biosolids
We are all responsible for generation of biosolids. Pennsylvanians produce an estimated 2.2 million tons of wastewater solids, or sewage sludge and residential septage, each year, nearly a quarter of a ton per household.
This material has proven to be a valuable resource, when controlled and safely applied, as a fertilizer to help rejuvenate farmland, forests and minelands.
In order to ensure safe use of biosolids, Pennsylvania has updated its regulatory program. The regulations focus on setting strict standards for biosolids quality before land application and requiring generators to be more responsible.
This new approach was developed after extensive studies by the U.S. Environmental Protection Agency (EPA) and public review in Pennsylvania found land application is environmentally safe and beneficial to the soil. The regulations have been endorsed by the Solid Waste Advisory Committee, the Pennsylvania Water Environment Association and the Pennsylvania Septage Management Association.
Biosolids that do not meet the new environmental standards must either be incinerated or taken to a landfill for disposal.
What are Biosolids?
Biosolids are nutrient-rich organic material produced from the stabilization of sewage sludge and residential septage that meet specific quality criteria and are suitable for land application. The term comes from the most common method of their production – the biological processing of wastewater solids.
Residential septage is human or household waste in a liquid or solid form removed from septic tanks or cesspools. The nutrient content of residential septage is similar to sewage sludge and, when treated and processed, can also be beneficially land applied as biosolids.
Biosolids meet specific quality criteria and are suitable for land application. Some are land applied as a liquid, while others have water removed from them and are the consistency of wet soil. Other biosolids are in the form of compost material and pellets.
Biosolids are created through the treatment of domestic wastewater generated from public and private treatment facilities. Biosolids treatment can begin before the wastewater reaches the treatment plant.
Regulations require that industrial facilities, in many larger systems, pretreat wastewater to remove many hazardous contaminants before it is sent to a wastewater treatment plant. Wastewater treatment facilities then monitor incoming wastewater streams to ensure the quality of biosolids meet the pretreatment standards.
Federal and state standards for pollution discharge have helped wastewater treatment plants institute effective pre-treatment programs. As a result, the quality of wastewater discharges has been improved, as has biosolids production.
Once wastewater reaches the treatment plant, it goes through physical, chemical and biological processes which clean it and remove the solids. The collected wastewater solids then undergo extensive stabilization treatment. This treatment reduces odors, pathogens, or disease-causing organisms, and vector attraction, or a characteristic of the wastewater that attracts rodents, flies, mosquitoes, etc.
Stabilization treatment includes such processes as digestion, lime stabilization, pasteurization and composting. The treatment changes the temperature, organic matter, moisture content or pH of the sewage sludge solids.
Solids processing equipment at a wastewater treatment plant or other facility is used to change the chemical and physical characteristics of the wastewater solids to a biosolids product that may safely be applied to the land.
There are many examples of biosolids being safely applied in communities. For instance, the Carlisle Water Pollution Control Facility in Carlisle Borough, Cumberland County, is an advanced wastewater treatment facility with a current operational flow average of 4.2 million gallons per day.
Since the activation of the facility in August 1981, the biosolids generated have been beneficially recycled through an extensive land application program.
In its sixteenth year, the program continues to expand. The program initially included five farms with a total of 395 permitted acres and has grown to include 25 permitted farms with approximately 1,845 acres. The borough land applies an average of 1,900 dry tons of lime stabilized biosolids per year, while making sure that every effort to inform the public is taken.
You may tour the Carlisle facility by visiting the DEP website at www.dep.state.pa.us (choose Subjects/Biosolids.) Contact Jim Bridges, Carlisle Borough, 717-240-6993, for additional information.
How are Biosolids Recycled?
Farmers and gardeners have been recycling biosolids for years. Biosolids, meeting strict quality criteria, help promote crop and forest growth. Also, they have helped promote the return of vegetation to mine reclamation sites and abandoned mines. If stringent treatment requirements are met, biosolids may even be sold or distributed for use on lawns and home gardens.
The application of biosolids reduces the need for commercial fertilizers. Recycling biosolids instead of disposing of them saves landfill space and can save communities money.
Agricultural Recycling
Biosolids meeting strict quality criteria and applied at approved rates help improve crop growth and yield, according to studies done by the Pennsylvania State University and others. Nutrients found in biosolids, such as nitrogen, phosphorus and potassium and trace elements such as calcium, copper, iron, magnesium, manganese, sulfur and zinc, are necessary for crop production and growth.
Biosolids reduce the farmers production costs and replenish the organic matter that has been depleted over time. The organic matter improves the soil by increasing its ability to absorb and store moisture.
The organic nitrogen found in biosolids is used very efficiently by crops because it is released slowly throughout the growing season. This enables crops to absorb the nutrient as they grow. This efficiency lessens the likelihood of nitrogen pollution in groundwater.
Mine Reclamation Recycling
Biosolids have also been used successfully at mining sites to help reestablish vegetation. The organic matter and plant nutrients in biosolids regenerate the soil layer. Biosolids are especially helpful in restarting plant growth at abandoned mine sites where there is very little or no topsoil.
For example, at the Lobb Mining Companiess Halfway Operation in Snow Shoe Township, Centre County, the objective was to revegetate the site. Several conventional plantings failed over a period of two to three years. As a result of the land application of biosolids to the site, the company now has a productive soil structure and an abundance of vegetation. As a result of the project, more than 200 acres of barren strip-mined land was reclaimed. In doing so, they have controlled runoff, and eliminated sedimentation to the receiving streams, thus improving the water quality.
For additional information about this project contact Douglas Saylor, Hawk Run District Mining Operations, at 814-342-8200.
Forestry Recycling
Biosolids have been found to help timber grow. In the same manner that biosolids help crops to grow, they also provide nutrients to our forests. Biosolids help forests grow more quickly and more efficiently.
Home Recycling
If treatment requirements are met to produce exceptional quality biosolids, they are considered landscape grade and may be sold or distributed for use on lawns and home gardens.
Landscape-grade biosolids must meet the most stringent standards for metal concentrations, pathogen reduction treatment and vector attraction reduction. This ensures the greatest level of protection to public health and the environment. Landscape-grade biosolids must also be non-liquid and cannot be recognizable as human waste.
Many homeowners and commercial appliers use composted, heat-dried or other forms of landscape-grade biosolids on gardens, flowerbeds, golf courses and city parks.
How are Biosolids Safely Land Applied?
Most experts agree that when properly managed, biosolids application is a safe practice that will not harm people or the environment. The organic matter in biosolids improves soil tilth – suitability for crop growth – and water-holding capacity. When biosolids are applied to soil with a minimum pH of 6, the risk imposed by the movement of metals into groundwater or uptake by crops is insignificant.
Before being used, biosolids are analyzed to ensure they meet DEP and EPA standards. They are analyzed for pathogens, nutrients, PCBs (polychlorinated biphenyl) and metals.
Unless they meet landscape-grade standards, biosolids applied to a particular site first must be evaluated by the biosolids generator for proximity to water supplies, soil characteristics, slopes, vegetation, crop needs and the distances to surface and groundwater.
Then the agronomic rate, or rate necessary to meet the nitrogen requirement for crops to grow, must be determined to ensure the appropriate quantity of biosolids are applied to the land. The biosolids application rate is specifically calculated to match how much nutrients the particular crop requires. The agronomic rate cannot be exceeded. Nutrient management technicians work with farmers to assure proper land application and nutrient control.
Site operations are monitored by both DEP and the permittee, or the person permitted to prepare biosolids. The permittee is required to maintain records that include a background soil analysis and annual cumulative soil metal loadings, as well as nutrient, chemical and pathogen analyses of the biosolids used for land application.
Biosolids, other than landscape-grade, may not be applied to farmland, forests or mine reclamation sites that are within 100 feet of a stream; within 300 feet of an occupied dwelling or water source; within 11 inches of a seasonal high water table; or within 3.3 feet of the regional groundwater table.
What is the Impact on Human Health and the Environment?
DEP's regulations and standards are based on more than 25 years of scientific research and an EPA risk assessment of processed biosolids use. Also, before finalizing the regulations DEP independently evaluated data on organic chemicals, viruses and parasites that might be found in biosolids. Both DEP and EPA have examined how the biosolids could directly or indirectly affect human health and the environment, including groundwater, air and soil quality, and surface water runoff, and established minimum safe concentrations for biosolids to be land-applied.
During the past 20 years, DEP has permitted more than 1,500 sites for the application of biosolids. This number, representing both active and closed sites, has not resulted in any water quality impacts on surface or groundwater. This shows that when properly managed, biosolids do not pose a threat to human health and the environment.
DEP's regulations require biosolids to meet very stringent standards for the elimination of disease causing organisms; the reduction of conditions that may attract vectors, flies and other disease carrying organisms or cause odor problems; and the control of maximum metals concentration.
How are Biosolids Regulated?
DEP's regulations for biosolids have been revised to make sure that biosolids meet strict quality standards and can be safely applied to the land. Anyone who generates biosolids, including wastewater treatment plants and septage haulers, must get a permit from DEP before biosolids can
