Case Studies

A field study was conducted in cooperation with Dr. R. Armon and Dr. F. Orshansky at the Center of Research in Environmental Engineering in Technion, Haifa 3200, Israel February 23 to May 17, 1994.

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.

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.

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.

Ecological Laboratories Inc. was contacted by Empresas Publicas to determine if bioaugmentation with MICROBE-LIFT®
technology could assist in the operation of their anaerobic digesters.

Zutphen is a medium sized activated sludge system treating an average of 6,600m3 of wastewater per day. The plant comprises two parallel trains with segregated recycle lines so that a side-by-side comparison could be conducted.

The primary influent pond is in a series of seven oxidation and maturation ponds serving the municipality of Drakenstein, S. Africa. This system was designed to allow the final maturation pond to be a polishing pond for nitrification to allow effluent of suitable quality to be discharged to the river. However, due to the high level of incoming organics the initial ponds are not effective enough to allow the system to work as designed. The key to this system is to improve treatment in the initial influent
pond to a level that allows efficacy in the remaining system.

A city of 14,000, Kerman is located 15 miles West of Fresno, CA. As the business and commercial center for Fresno County, this city was cited as one of the fastest growing cities in central California with 150% growth since 1990. Typically, fast population growth puts a strain on local services and the town’s sewer maintenance was no exception.

Busan is the second largest metropolis in South Korea. With a population of 3.6 million, it is second in size only to Seoul. With rapid urban development the city of Busan was continually challenged with increasing wastewater treatment demand.
The city’s anaerobic digester was only functioning at 70% of design efficiency based on volatile suspended solids (VSS) reduction.

Shoal Lake is a small town of less than 1,000 people in western Manitoba. The wastewater generated by the town is treated in a series of three aerated facultative lagoons to lower key pollutant discharge parameters prior to discharge to the lake. The lagoons are in series and referred to as Cell #1, #2, and #3. Cells #1 and #2 are both 49 years old with a surface area of 5 acres and a depth of 6 feet with an approximate volume of 10 million gallons (MG). Cell #3 has been in service for 26 years and is 7 acres by 6 feet deep with an approximate volume of 14 MG. Normal inflow into the series of lagoons is approximately 0.22 million gallons per day (MGD). There is an estimated 2 feet of sludge in each lagoon. This sludge build-up reduces the working volume of the lagoons and the hydraulic retention time (HRT) of the system by about 30%.

A WWTP in Southeast Georgia located on a resort island has a 3 million gallon per day flow. The WWTP was experiencing major odor problems at the head of the plant, as well as poor digestion and settling of bio-solids in the SBR’s and aerobic digesters. The odors were primarily H2S and were the source of numerous complaints from the residents living in the vicinity of the WWTP. The plant was hauling and disposing an average of 125 to 150 tons of bio-solids per month at a cost of approximately $60 per ton, which equates to $7,500 to $9,000 total average hauling/disposal charges per month.