Biological wastewater treatment process with activated sludge and compact wastewater treatment plant

摘要

Method for biologically cleaning sewage has anaerobic (3), aerobic (9, 10) and clarifier (17) stages, returns some activated sludge to the anaerobic stage (3) and keeps the sludge concn. and oxygen content within predetermined levels. The novelty is that the anaerobic stage (3) has two zones (5, 7). The sludge content is continuously monitored and kept at 5 kg/m3; and the oxygen content in the aerobic stage kept at 1.5 mg/l. The clarifier (17) is small and integral. Also claimed is a compact plant (1) for the above method where the novelty is that the anaerobic stage (3) is in two zones, one above the other. A monitor (15) and an aeration system (11) are used to regulate sludge activity in the aerobic stage (9) and the clarifier (17) has lamellar separators (18).