Quasar, wastewater authority partner on anaerobic digestion project

Quasar Energy Group, Independence, Ohio, has recently completed a design project at the Eastern Ohio Regional Wastewater Authority (EORWA) to provide technology and equipment to establish an energy neutral facility by harvesting residual energy in  wastewater processed at the wastewater treatment plant and organics from the region, which will help to stabilize the rate structure for its customers.

Biosolids generated at the plant will be designated as “Class A/EQ Quality” product, which will be used for beneficial reuse as a replacement for commercial fertilizer used by Ohio Valley farmers. These improvements support EORWA’s environmental responsibility and sustainability goals, according to a news release.

In order to become an energy neutral facility, EORWA introduced co-digestion to their plant. Traditionally, food scraps and expired beverages generated in the Ohio Valley are sent to landfills. Today, these energy dense materials can be accepted with EORWA’s new liquids and solids receiving equipment, and then mixed with sludge from the plant to be processed in anaerobic digesters to produce biogas for renewable energy. The biogas is converted to electricity with a microturbine that has enough capacity to offset 100 percent of the electrical use at the wastewater plant.

EORWA and quasar entered into a biomass supply agreement where quasar will manage the incoming biomass to the plant to provide consistent operations, which has the capacity to accept 27,000 wet tons per year. Tip fees from material delivered, energy savings and lower biosolids disposal costs will help offset the capital costs for the project, the release says. EORWA is accepting various organic waste streams and can provide the services needed to process them.

Quasar has also been working with EORWA on the marketing of their newly constructed grit pad and increasing the volume of industrial wastes, including landfill leachate, which is received directly into the plant.  These industrial customers bring in additional sources of revenue to offset EORWA’s capital and operating expenses at treatment plant.

Class A biosolids benefits EORWA by providing more flexibility in its beneficial use. Class A biosolids, which are primarily used for agronomic benefit on area farms as natural fertilizer for crops, help area farmers offset the need for commercial fertilizers, which are derived in part by burning fossil fuels or mining of minerals. The Class A thermal treatment process is achieved through a series of heat exchanges and into a thermal treatment tank where it is held to satisfy a time and temperature formula per the United States Environmental Protection Agency (EPA) requirements.