The BWPCF is a Grade V Facility which utilizes the Conventional Activated Sludge Method of treatment to remove conventional and nonconventional contaminants from the wastewater. The BWPCF is one of the very few Facility's in the world that treats a combination of sanitary wastewater and paper mill process wastewater in the same Facility.

The BWPCF is required by its NPDES Discharge Permit issued by the Federal Environmental Protection Agency (EPA) and the State of Maine Department of Environmental Protection (DEP) to treat 5.19 MGD through Secondary Treatment. Peak design capacity, which results from stormwater run-off in areas with combined sewer systems will be 13 MGD. Whatever combined wastewater flow from the City which does not receive secondary treatment will receive at a minimum preliminary treatment, primary treatment and disinfecting before it will be discharged to the Penobscot River. Because of the nature of the waste all process wastewater from Eastern Paper will always receive primary and secondary treatment.

All secondary treated flow from the BWPCF must meet the EPA and DEP permitted limits for BOD, TSS, and % Removal. Even though the BWPCF has a Significant Industrial User on-line with them, the Facility still must meet sanitary wastewater discharge limits. The facility must meet limits for BOD and TSS of 50 mg/L Daily Max., 45 mg/L Weekly Aver., and 30 mg/L Mthly Aver. Percent Removal must be 85% or higher. Currently the Facility has demonstrated it is capable of discharging secondary treated wastewater with BOD and TSS levels of no higher than 10 mg/L, and a Mthly Aver. of 4 mg/L on a consistent basis. Percent removal of BOD and TSS for 1998 was 98%.