This Technical Report specifies a procedure for the chemical conditioning in laboratory of sludges.This Technical Report is applicable to sludges and sludge suspensions from:- storm water handling;- urban wastewater collecting systems;- urban wastewater treatment plants;- treating industrial wastewater similar to urban wastewater (as defined in Directive 91/271/EEC);- water supply treatment plants.This method is applicable to sludge and sludge suspensions of other origin