Wastewater TreatmentBackground Information
The community sewage system serving the Westminster area is owned and operated by the City of Westminster. Some of the sewer lines and pumping stations in the unincorporated area were planned, designed, and constructed by the Carroll County Sanitary Commission and then turned over to the City for operation and maintenance. The existing and planned service area is located centrally in Carroll County and contains approximately 7,780 acres. The original system has been in existence since 1935. In 1973, a new plant was constructed along Little Pipe Creek, about three miles downstream from the old plant, which is no longer in service.
The wastewater Treatment Plant is located near the intersection of Old New Windsor Pike and Route 31. In 1991, a project was completed to upgrade and expand the capacity of the plant from 3 million gallons per day (MGD) to 5 MGD. The modifications were recommended in the 201 facilities plan. Improvements include an automated bar screen, a grease and grit removal system, flow equalization tanks, two additional aeration tanks, chemical phosphorous removal, an expansion of the existing laboratory, a sludge dewatering facility, additional sludge digesters, improved secondary clarifiers and a disinfection tanks. The modifications improved the operating efficiency of the plant and as well as the quality of the final discharge effluent. Also included in the treatment plant improvements was construction of a separate septage receiving facility.
Because the City is committed to preserving the environment, in 1996, the City entered into a voluntary agreement with the State of Maryland to construct a Biological Nutrient Removal system (BNR) with 50 percent State funding. Construction of the BNR system was completed in 2000. The BNR system allows the plant to biologically reduce Nitrogen and Phosphorous in the final effluent without the addition of costly chemicals.
Sludge from the treatment plant is presently hauled from the treatment plant and land applied to farm fields as a source of fertilizer. Wastewater plant personnel haul and apply the sludge to state permitted farms based on field availability and weather. The City has a contract with Integrated Agronomics Inc. of Emmitsburg, Maryland to haul sludge on an as needed basis.
The sewage collection system includes 11 sewage pumping stations and approximately 160 miles of sewer mains. Infiltration and inflow problems have been evaluated through a Sewer System Evaluation Survey (SSES). Correction of these problems has reduced or stabilized the average daily flow at the plant. Additional work is anticipated to further reduce infiltration and inflow into the sewage system.
Current Facts and Figures
The City of Westminster Wastewater Plant is an activated sludge facility with a design capacity of 5 million gallons per day (MGD). Presently the plant is treating 4.51 MGD and achieving a high percentage reduction in Environmental Protection Agency (EPA) mandated effluent parameters over influent characteristics. In 1993, the wastewater plant received an award from the EPA for maintenance management excellence.
In 2004 the City completed an upgrade to the chemical disinfection system for the plant effluent. The upgrade replaced the gas chlorine and sulfur dioxide system with a liquid sodium hypochlorite and bysulfite feed system. The City recently completed the study phase for upgrading the plant to meet the new Enhanced Nutrient Removal goals established by the State of Maryland, design is expected to begin in 2009. The Environmental Protection Agency and the State of Maryland regulate Westminster’s wastewater plant effluent. See the chart of the plant's discharge permit, influent characteristics, and final effluent levels of the permitted parameters.
Read Water Environment & Technology (WE&T) Magazine's article about the Westminster Wastewater Plant