Perry Township in Fayette County, Pennsylvania is one of the first SBR plants to utilize a surface mounted process aerator/mixer, which is a significant improvement over the traditional diffused air network designs. The new layout offers substantial capital investment savings as well as significant reductions in noise, operations/ maintenance, and energy consumption. KLH Engineers, Inc., headquartered in Pittsburgh, PA was awarded the contract to provide engineering construction services on the project.
KLH has a long history of SBR design, installing one of the first batch reactors in the United States in 1983.
The design of the Perry Township SBR is based on an average daily flow of 100,000 gpd of municipal wastewater. The plant layout consists of three rectangular concrete tanks - two batch reactor tanks measuring 13' wide x 35' long x 20' deep and one sludge holding tank measuring 9' wide x 25' long x 20' deep. Instead of diffused air, one 10 I IP Triton aerator/mixer is installed in each of the reactors. In addition, one 5 HP Triton unit is installed in the 30,000 gallon sludge holding tank to provide aeration and mixing.
Each reactor also contains a decanter. The decanter is a fixed four-sided stainless steel decanter with solids exclusion baffles that is moved up and down via a worm gear driven jack screw to produce a controlled and high quality flow of effluent during the decant phase. The four-sided design allows for a reduction in the overall size of the decanter thereby reducing cost and simplifying installation.
The process aerator/mixers are float mounted units that ride vertically up and down on stainless steel slide pole assemblies as the water level in the tanks change. Polyurethane rollers are integrated into the float assembly and enable the units to move smoothly along the slide poles without binding. This enables the equipment to be easily inspected and maintained from the surface of the tank. In fact, all of the equipment in the SBR is easily accessible from the top without ever needing to drain the basins for inspection or service.