7.2.1 Screen filter presses, travelling screen presses
7.2.6 Conditioning systems
7.2.8 Mechanical surplus sludge thickeners
7.2.15 Augers
7.2.19 Other sludge thickeners, sludge containers
7.2.20 Other sludge dewatering systems
7.2.21 Other systems for the optimisation of sludge dewatering
7.3.1 Belt dryers
7.3.19 Other drying processes
11.1.9 Iron and steel production
11.1.47 Sludge liquors
12.3.7 Drying plants
21.1.1 Desludging of surface waters