Thickening of surplus or sapropel sludge involves moving sludge past membranes which trap solids but allow water passage

摘要

The sludge passes one or more membranes(2) whose pores allow water to pass through, but prevent passage of sludge. Membranes(2) are in the form of tubes, plates or hollow fiber membranes. Thickening occurs in the sapropel container or in the operating system for the latter. The sapropel container has one or more sludge circulation units(1), each containing membranes and the container is operated continuously by feeding a known quantity of raw sludge into it(3) and extracting(5) a corresponding amount of sapropel sludge. Dry sludge content in the container is not less than5%. In a process for thickening of surplus sludge the thickening stage occurs in one or more circulating units, each with membranes through which water can pass. Independent claims are included for: a) a sludge circulating unit with one or more membranes(2) through which water is extracted from the circulated sapropel or surplus sludge; b) a sapropel sludge container for sewage plants for anaerobic treatment of sapropel sludge which includes one or more circulating units; c) a surplus sludge container connected to one or more circulating units.