The DRGWQTC was designed as a 15 million gallon per day preliminary and activated sludge treatment facility. There are no primary sedimentation facilities or sludge processing facilities at the DRGWQTC.
The raw influent wastewater flows through three coarse bar screens to the influent pump station. Four pumps life the raw wastewater to an aerated grit chamber. From the grit chamber, flow through the remainder of the plant is by gravity.
The secondary treatment facilities have the capacity to operate in either a complete mix or contact stabilization activated sludge process. Current operation is with the complete mix mode, utilizing two of the aeration basins. The wastewater flows from the aeration basins to three final settling tanks. Final settling tank effluent flows to chlorine contact basins for disinfection. Following chlorination/dechlorination, final effluent flows to the Ohio River.
Settled secondary sludge is wasted to temporary aerobic digesters. The temporary aerobic digesters are the two additional aeration basins that are not currently in service because of low influent organic loading and flow. Waste activated sludge is pumped to the Morris Forman Water Quality Treatment Center (approximately 12 miles) for further processing about once every week.
MSD recently completed installation of a $2+ Million project to control odors from the treatment plant. The project included installation of a carbon adsorber to treat sewage odors, a biofilter to treat the aeration basin influent channels and installation of fine bubble diffusers to reduce odors from the aeration basins. Provisions were also made to reduce noises from the plant. "Baseline" odor and noise testing (prior to construction of the new project) and follow-up odor and noise testing (after completion of the project) were performed.
In addition, improvements were made to reduce noise levels from the treatment plant. A noise survey conducted in June 2004 indicated the following:
- Noise emissions from individual sources have been reduced by 10-14 decibels (dBA);
- Noise from plant at nearby residences have been reduced by 6 dBA;
- The water quality treatment center is determined to be inaudible relative to all other ambient noises, with the possible exception of a resident adjacent to the transformer; and,
- The noise consultant concluded that the plant is acceptably quiet.
West County Local Limits
|Parameter||Maximum Daily Concentration|
|Total Arsenic||0.57 mg/l|
|Total Cadmium||0.43 mg/l|
|Total Chromium||5.0 mg/l|
|Total Copper||3.8 mg/l|
|Total Lead||1.1 mg/l|
|Total Mercury||0.0015 mg/l|
|Total Nickel||4.1 mg/l|
|Total Silver||1.2 mg/l|
|Total Zinc||5.3 mg/l|
|Cyanide, Amenable||1.2 mg/l|
|Oil & Grease (Hydrocarbon)||100.0 mg/l|