CDM is assisting the Hampton Roads Sanitation District (HRSD) develop and maintain its regional solids management strategy as part of a plan to increase solids processing capacity and improve overall biosolids quality at the Nansemond wastewater treatment plant, a 30-million-gallon-per-day facility. To guide HRSD in determining the appropriate improvements, CDM evaluated advanced anaerobic digestion, thermal drying, and the marketing of pelletized biosolids for beneficial reuse.
HRSD ultimately decided to proceed with advanced anaerobic digestion, selecting a two- phase acid-gas process. Class A stabilization will be achieved at an off-site composting facility. CDM is also designing a new regional grit and grease facility, improvements to the digesters, and modifications to the centrifuge dewatering facility.
The acid-gas digester system will consist of two acid-phase digesters and three gas-phase digesters, two of which will be converted from the existing digesters. Some of this gas will be used as a heat source for the plant and the excess will be released through a flare, conserving energy and reducing expenses.
CLIENT: Hampton Roads Sanitation District
LOCATION: Suffolk, Virginia