COMPOSTING IN SPOTSYLVANIA COUNTY, VIRGINIA

In response to increased pressure to limit land application of biosolids and the need to reduce the quantity of material being landfilled, Spotsylvania County embarked upon an aerated static pile composting program in 2002 to manage undigested dewatered wastewater treatment plant (WWTP) solids cake from their Massaponax WWTP. The primary bulking agent used was ground brush collected through a convenience center and at the Livingston Landfill. The quantity of dewatered solids being composted increased from approximately 400 tons per month in 2002 to in excess of 800 tons per month in 2003. As the amount of material processed increased, odor issues developed because no odor control was included in the initial facility. Process improvements were made including aeration station layout modifications, increased aeration rate delivery and switching from negative aeration to positive aeration mode. These changes in conjunction with performing detailed classroom and field training of operators has resulted in the elimination of odor issues at the facility. Currently, in excess of 900 tons per month of WWTP solids are being composted at this site. This quantity is expected to triple by the year 2015.This paper provides information on the process Spotsylvania County used in developing a pilot compost project into a successful full-scale project. The main philosophy used was to start small, gain knowledge and success, and then grow the facility into a dependable means of solids management. Plans for future expansion of this solids and brush co-composting program will be presented including facility requirements to ensure odors are effectively managed and product markets are enhanced. Information will be presented on the process flow, capital & operating costs, facility (aeration and building) upgrades, odor management, and product marketing strategies currently used by the County in developing this operation. In 2003, actual operating costs including amortized capital and O&M costs amounted to only 40.37 per ton of solids processed. Several markets have been established for the use of compost including soil stabilization of department of transportation highway embankments, acid soil embankment stabilization and other landscaping practices. Coordination with local landscapers to produce various product types has also been a key to selling all the compost produced (10,000 cubic yards annually) at the facility after only one year of actively marketing the product. Data regarding actual revenue generation through the sale of compost product and the net impact on operating and total annualized costs will be presented.