Stimulated by diminishing sludge disposal facilities in agriculture in the Netherlands, an increased interest has developed for improved sludge dewatering techniques. The required changeover to sludge treatment processes like composting, drying and incineration is expensive and costs are considerably influenced by extended mechanical dewatering capabilities. In cooperation with the Dutch Water Authorities and industry, DHV Water BV has been performing full-scale test programmes since 1989. Each test programme involves the treatment of various sludges, simultaneously dewatered using between two and nine different types of full-scale equipment, such as beltpresses, decanters, filterpresses and high pressure equipment. A combination of proper process design and control, together with the latest developments in the design of dewatering equipment, have resulted in dry solids percentages far higher than any reported to date. In this respect, the decanter has been shown to be an attractive alternative in many situations where filterpresses are used for the dewatering of municipal sludges.