Wastewater Treatment
Raw sewage from the communities served by the South Central Wastewater Authority Treatment Plant
enters the facilities from three separate sewer force mains. From that point the wastewater sequentially
flows through various tanks and equipment, each unit designed to remove a specific category of solid
material or other type of pollutant from the flowstream. Some pollutants are dissolved (or soluble)
in the water and require biological conversion to a solid residue for their removal.
Naturally occurring bacteria growing in the aeration tanks use this soluble material for food
and convert it to solid material which is then removed from the wastewater and further treated
by a separate process. The liquid portion is oxidized and nitrified in the aeration tanks
and solids are removed in the clarifiers. The clear effluent is disinfected before being
discharged to Appomattox River.
Click image to enlarge.
Wastewater entering the South Central Wastewater Authority Treatment Plant contains approximately 150 milligrams per liter (mg/l) of suspended solids and 210 mg/l of biochemical oxygen demand (BOD), and in addition, up to 16 mg/l of ammonia and 5 mg/l of phosphorus. The Virginia Department of Environmental Quality has required that the Authority discharge less than 30 mg/l or suspended solids, 16.8 mg/l of BOD, 1.8 mg/l of ammonia and 2.0 mg/l of phosphorus as well as a number of other restrictions to maintain the water quality in the Appomattox River.
Solid residue removed from the wastewater is pumped to thickening and dewatering facilities which concentrate the solids to approximately 20% solids (80% water). The solids are then mixed with lime which raises the pH of the material to provide stabilization. The mixture is further dried on a covered storage pad before being safely spread on land.
