Wastewater sludge as a resource: sludge disposal strategies and corresponding treatment technologies aimed at sustainable handling of wastewater sludge

The paper discusses different strategies for the disposal of wastewater sludge, particularly the "use on land" strategy and the "productification" strategy. In the "use on land" strategy the new regulations in Europe call for stabilization as well as disinfection of sludge to be used on land. The paper discusses the design and operation experiences with stabilization/disinfection methods in Norway where such treatment has been compulsory since 1995. In the "productification" strategy it is differentiated between the production of "bio-soils" and production of specific products (energy, nutrients, coagulants etc) and the "marketability" of these products is evaluated. An example of a sludge treatment concept aimed at recycling - the KREPRO process - is presented.