The Municipal Authority of the City of Sunbury (the Authority) owns and operates a Wastewater Treatment Facility. The treatment facility serves approximately 9,905 residents of the city and the Hamilton and Oaklyn areas of Upper Augusta Township. The WWTP is designed for a “dry weather” hydraulic loading of 4.2 MGD and an Influent BOD5 loading of 14,011 lbs/day.
The treatment plant employs physical and biological treatment processes to attain treatment goals. The plant discharges treated effluent to Shamokin Creek and operates under NPDES Permit No. PA 0026557. It is designed to handle a flow of 4.2 million gallons per day (MGD) and a permitted average monthly organic effluent concentration of 25 milligrams per liter (mg/l) of biochemical oxygen demand (cBOD5) per day.
The treatment process begins with preliminary treatment that consists of fully automated Cog Screens to remove gross solids and floatable material. Grit removal is accomplished using a vortex type grit removal system. After preliminary treatment, flow enters the wet well and is pumped to the aeration basins where it is mixed with return activated sludge (RAS) to create mixed liquor. The mixed liquor flows to the clarifiers where it settles and is constantly returned to the aeration basins.
During wet weather events (rain and/or snow melt) flows in the collection system increase dramatically creating a situation for by-pass events. A 1.5 million gallon equalization basin allows for the capture of the “first flush” which typically is made up of the highest strength wastes. This first flush is then held in the equalization basin until flows return to normal at which time the equalization basin is allowed to drain into the process for treatment.
The treatment process also incorporates a Biological Nutrient Removal (BNR) component. The BNR component consists of a tank 58ft x 116ft x15ft. Recycled RAS and raw flow are mixed in this reactor by floating mixers, with no additional O2 added, in an attempt to create an anoxic zone.
Disinfection is accomplished by Ultra Violet Light (UV).
Wasted sludge (WAS) is thickened by a gravity belt thickener and then pumped to one of two aerobic digesters. After digestion, sludge is transferred to a 500,000 gallon aerated holding tank where it is stored. All sludge produced is dewatered using a belt filter press and disposed of at the Wayne Township Landfill