Case Studies
The sewage treatment plant of the borough Deutsch-Wagram is situated in the south west of the settlement on the left shore of the Rußbach and has been in operation since 1969. The drainage area is 350 hectares and the degradation performance is more than 90% based on mechanical, chemical and biological treatment. The waste water entering the sewage work at the supply tank is lifted up with screw pumps to the level of the sewage work and passes through a bar screen. A mechanical scraper removes coarse matter from the waste water. Then, the wastewater flows through the circular degritter where granular components are separated. Through a distributor structure the mechanical pre-cleaned wastewater enters the activated sludge tank with a capacity of 1440m3. The biological treatment is carried out by the activated sludge process. To cover the oxygen demand, air is supplied with cage rotor aerators into the wastewater. In the secondary settling tank, with a capacity of 2.300m3, the sludge settles down and is separated from the wastewater, treated biologically, then discharged to the receiving water (Rußbach). Through a siphon pipe the settled sludge enters the sludge recycling pump station. With screw pumps the sludge is pumped back into the activated sludge tank.
The Bath WWS is a regional facility that covers many small communities over a large area serviced by a network of domestic sewage collection conduits. Total Population Equivalent (PE) of 537.000 is pumped to this central facility on the coast of Southern Zeeland. The facility is a well designed and operated wastewater treatment plant. The basic design brings the domestic sewage to a gross filter and then into a collection diverter that separates the flow into 4 trains. In each of the trains, the first tank is a covered primary (facultative) receiver, covered with thick floating Styrofoam sheets to lower odor emissions. From here it flows into an aeration tank system, and then onto large settling clarifier. After this point, the flow is dewatered and the pressed cake is further processed in anaerobic chambers.
S-10 is a flood mitigation river water holding pond in Penang, Malaysia. Drain water from Georgetown is channeled into this 150M x 85m x 2m deep retention pond before being discharged into the sea. Excess water in the pond is either drained into the sea during low tide by opening the tidal gate or through mechanical pumping when sea level is higher than the pond water level. The retention pond prevents ingress of salty seawater into Georgetown and allows free flow of surface drain water during heavy rain that coincides with high sea water level.