Treatment of Municipal Waste Water

International water conservation policy has focused especially on advanced waste water treatment. The inevitable consequence: a worldwide increase in the sewage sludge volume. How can the municipalities dispose of the growing volume in an environmentally acceptable manner and cost-effectively? The solution is highly efficient dewatering leaving as few residuals as possible. Because the higher the solids concentration of the sewage sludge is, the more economical the further processes are.

• Dewatering and thickening of municipal sewage sludge
• Superlative project: 30 decanters for thickening and dewatering sewage sludge
• Advantages of decanters
• Low required space
• Mobile systems

A superlative project is the Changi waste water treatment plant in Singapore. In the presently largest newly built waste water treatment plant in the world, 30 decanters of the CA 1036 series and CA 1035 have been installed for thickening and dewatering sewage sludge. The huge scroll-type centrifuges are additionally equipped with peripheral equipment, pumps, conveyors, flocculent stations and switchgear.

In comparison to other waste water treatment processes, decanters offer the advantage of a continuous operating mode combined with substantially less space requirement, which is crucial in this extraordinarily densely populated city state with around four million inhabitants. The plant is able to handle approximately 800,000 m³ waste water a day. By way of comparison, Berlin manages 650,000 m³ a day with a population of 3.5 million.

GEA Westfalia Separator Group is also a partner for innovative environmental technology in the Ukrainian Kharkiv. The three decanters from the UCB 505 series installed in the local waste water treatment plant in 2004 achieve the very high capacity of 40 m³ per hour with their relatively small bowl diameters. The three decanters replaced four decanters of older design and take up a third less space than the previous models. The dewatering performance in the dry substance is now up to eight times higher so that a substantially lower volume has to be disposed of. This means that the existing landfill space can be used for at least a third longer. With this municipal treatment plant, Kharkiv is already up to EU standard.

A representative example from Germany is the long-established chemical location Bitterfeld. GEA Westfalia Separator Group is making a tremendous contribution to reclaim the contaminated ground water after 100 years of industrial operation. The project scheduled to last for decades works with a sludge dewatering unit in which the decanter type UCD 536 is the core piece of equipment. This continuously operating horizontal centrifuge processes up to 60 m³ sewage sludge per hour for maximum dewatering. It is a self-contained unit installed in a forty feet long container and therefore fulfills all the requirements for unrestricted mobility.