The extension of Dong Ying (South suburbs) Water Works in Shandong started in December 2009. Dong Ying (South suburbs) Water Works is the first plant in China to use membrane filtration system supplying 100,000 tons of portable water everyday.
There are 12 permeate transfer pumps for this project. The pumps are rotary lobe type supplied by Börger of Germany. With the rotary lobe pumps, the flow rate can be easily controlled by using frequency inverter. The filtered water from the membrane systerm is transferred by the Börger pumps to the pipe.
The filtration system requires backwash for every two hours of operation. During backwash, the pumps are reversed in rotation, sending pressurized water in the reverse direction to clean the filter. Backwash waste is then discharged into a recovery sump.
After a period of 3 to 6 months, backwashing can no longer maintain the filtration flow rate. At that time, the membrane requires chemical cleanning. Börger rotary lobe pumps are also used for the transfer of acidic or alkali chemical cleaning agents.