Sewage sludge treatment for further processing of components - with pressing of screened sludge for storage, composting or drying

摘要

Process for treatment of sewage sludge is carried out by screening the sludge in a first stage, and conducting the resulting liquid to a conventional clarifying plant. In a second stage, the screened sludge is pressed to render its liquid content so low that it can be stored in a depot or composted or further processed by drying. Screening of the sludge may be performed with filter bags made of high-strength plastics e.g. polyamides. The liquid is treated conventionally e.g. flocculants and precipitating agents can be added to separate sludge components from the liquid. The consistency of the pressed sludge from the second stage corresponds to tht of a filter cake so that the residual material can be dried and burnt for disposal.