WHAT IS BIOSOLIDS COMPOST
Most municipal wastewater treatment facilities today utilize “biological wastewater treatment” to treat the wastewater from their communities. When wastewater undergoes biological treatment, the organic compounds (including nitrogen and phosphorus compounds) are broken down biologically by naturally occurring microorganisms that are maintained within the wastewater treat
ment facility. As the microorganism population increases, a portion must be removed from the treatment process each day in order to maintain a proper balance in the wastewater treatment system. The organisms that are removed are referred to as “biosolids”. The removed biosolids require some treatment of their own before they can be properly disposed of in a cost effectively and without creating an environmental nuisance. The USEPA has approved several methods for treating biosolids for disposal. At Seaford, composting is the method which is employed. The composting process begins by first removing excess water from the biosolids to produce a cake which can be handled by a front-end loader. This is accomplished on a machine called a “belt filter press”. An agricultural mixer is then used to blend the biosolids cake with woodchips which provide carbon for the composting process as well as minimize compaction of the mixture so air can flow freely through the compost piles. This mixture is then stacked inside a covered composting bay where the temperature and oxygen inside the pile can be monitored. The initial composting period lasts 14 days, during which the piles are required to meet specific temperature and oxygen requirements in order to improve the quality of the finished compost. Each pile is monitored and recorded twice per day to ensure required parameters are met.
• VAR (Vector Attraction Reduction): VAR refers to the process of breaking down and stabilizing the organic material in the compost pile in order to reduce the nuisance of “vectors” (such as mice or flies) being attracted to the finished product. As the composting organisms responsible for this do their job, they generate heat in proportion to the material they break down. The VAR requirements are achieved by maintaining pile temperatures above 40 deg C, with an average over all temperature of > 45 deg C.
• PFRP (Process to Further Reduce Pathogens): PFRP is an additional set of parameters used to produce a higher quality of finished compost defined as “Class A, Exceptional Quality” by the USEPA. To achieve this, the piles must achieve a peak temperature of 55 deg C or more for at least 3 consecutive days, and maintain an oxygen level above 5%. These increased temperatures greatly reduce the chance of potential pathogenic organisms surviving the composting process. When the 14 day period is complete, and all VAR/PFRP parameters have been met, the pile is broken down. If a pile fails to meet the required parameters, it is re-composted until the parameters are met. The material is then processed through a ¼ screen to remove the woodchips, which are reused, and the finished compost is stockpiled in a holding area. The finished compost is allowed to cure for at least 30 days prior to being distributed. Also prior to distribution, all finished compost is analyzed for nutrient content, specific metals and bacteriological indicators to ensure that the finished product is safe for use. Seaford’s biosolids compost consistently meets the VAR and PFRP requirements as well as the analytical limits established by the USEPA and State of Delaware. Because Seaford Compost meets these stringent criteria, it is considered a “Class A, Exceptional Quality” material according to EPA and State Standards. Seaford Compost is a member of the U.S. Composting Council, and proudly carries the Council's STA (Seal of Testing Assurance) Certification. Biosolids compost is an excellent way to “green up” your landscaping project while recycling valuable nutrients and micro-nutrients into the soil for optimum plant growth. Recycling these nutrients helps maintain and protect our valuable waterways. Biosolids compost can improve the quality of sandy soils by improving water and nutrient retention, making more nutrients available for plant growth. It can also improve the quality of clay soils by reducing compaction and improving soil aeration. Seaford Biosolids Compost is available year round, and may be picked up on Wednesdays and Fridays.
8:15am-4:45pm
7:15am-3:45pm (Summer hours, Memorial Day through Labor Day)
The site is closed from 12:00-1:00 for lunch. The cost is $10 / cubic yard. (A full size pickup bed will hold 2 to 2.5 cubic yards)
Other days/times may be available for bulk or commercial sales. Please contact our office for information. City of Seaford
Biosolids Composting Facility
403 Nanticoke Ave. Seaford, DE 19973
(302) 629-0120
