Sludge and gas line Tobl
The sludge from the pre-clarification (primary sludge)  is statically dewatered in the pre-thickeners . The excess sludge is removed from the final clarifier  and dynamically dewatered via the screening belt. It is then heated to 40°C and digested in an airtight digester . The sludge stabilized in this way is then dewatered with screw presses .