Singapore standardized on the Series 5400 control pinch valve for use on waste-activated sludge.Click here to enlarge imageThe plant’s design incorporated an enclosed egg digester, a revolutionary trend in solid-waste treatment that improves sanitation, controls odor and allows for more accurate temperature manipulation. Egg digesters allow for complete sludge mixing. They eliminate dead spots and reduce solids accumulation. Mixing occurs throughout the entire tank, preventing settling and stratification.
To match this efficiency with the best available process equipment, designers of the egg digester made Red Valve pinch valves a standard specification for the egg digester. Many of the hundreds of such valves installed are involved in the circulation process of the plant’s enormous egg digesters, where sludge is highly solidified and abrasive.
As word spread of the egg digester’s many advantages, wastewater treatment plants in Los Angeles, Boston Harbor, Salt Lake City, Gwinnett County, Georgia, in the USA are also employing this design. Each plant, ranging in capacity from 20 to 200 mgd, is equipped with Red Valve pinch valves for throttling and isolation.
The Seletar plant in Singapore went online in the latter part of 2000. From the point at which the raw sewage enters the facility, across the headwork section, during all sludge-processing phases and onward through effluent discharge, Red Valve manual and control pinch valves are in use. Applications at Seletar include influent flow, primary sludge, primary scum, grit valves, digested sludge, blended scum, drain water, sampling lines and waste-activated sludge.
By employing a total-system approach, Red Valve ensured that the entire plant would reap the benefits of superior pinch valve technology, including excellent throttling characteristics for control applications and positive, drop-tight shutoff for isolation. It made use of its own expertise and worked closely with Kinhill Tan and the Ministry of Environment to provide Seletar with the best product selection for its myriad of needs. Elastomers for the rugged pinch sleeves were hand selected for compatibility in each individual process.