Systems for the biological removal of nitrogen and phosphorus in a process using activated sludges

摘要

Systems for the biological removal of nitrogen and phosphorus in a process using activated sludges. The system, which is suitable for use in a method for the treatment of wastewater using activated sludges and combines an anaerobic process with an aerobic process comprises a primary settler 1, an anaerobic reactor 2, anoxic tanks 3, 4, anaerobic reactor 5, a secondary settler 6 and optionally a hydrolysis tank 7. The system is characterised in that the anoxic tanks (3, 4) are placed in parallel with the said reactors 2 and 5, the outflow from anaerobic reactor 2 is distributed between anoxic tanks 3, 4 and internal recycling is established between aerobic reactor 5 and an anoxic tank 3, together with external recycling between a secondary settler 6 and an anoxic tank 4, and supplementary recycling between an anoxic tank 4 and anaerobic reactor 2. IMAGE