Sludge Pre-thickener and Automatic Sludge Thickener “AZK”
Produced excess sludge in wastewater treatment plants is stored and it is desirable to have minimum water content. Sludge pre-thickener is used for sludge dewatering to ca. 2 – 3 weight percentage, automatic sludge thickener AZK dewaters sludge to ca. 10 – 20 weight percentage.
Sludge pre-thickener is a plastic and/or rust-resistant steel tank emerged in the aeration zone and fitted inside with a pump. Automatic sludge thickener AZK is made of stainless steel.
Plastic or rust-resistant steel tank of sludge pre-thickener is fitted on its top and middle part with slide gates controlling the flow of thickened sludge suspension. A pump is installed in the tank bottom part and is controlled with a time switch and pumps the thickened sludge suspension out to a container.
Sludge suspension pumped to an automatic sludge thickener AZK is mixed with a solution of auxiliary organic flocculant. When suspension becomes filterable it passes on to automatic sludge thickener AZK where sludge water is separated and it returns back to treatment process. Separated sludge when thickened reasonably is pumped out with a screw pump to a container for storage and further thickening.
Based on laboratory analyses the thickened sludge from a container is disposed of either with dumping, composting or burning.