This draft European Standard specifies a method for determining the zone settling velocity (ZSV) and the Compression point. This draft European standard is applicable to sludge and sludge suspensions from: storm water handling; urban wastewater collecting systems; urban wastewater treatment plants; plants treating industrial wastewater similar to urban wastewater (as defined in Directive 91/271/EEC); water supply treatment plants. This method is also applicable to sludge and sludge suspensions of other origins.