ADVANCED METHOD FOR TREATING WASTEWATER USING NITRIFICATION TANK EQUIPPED WITH RID (ROTATION IMMERSION DISKS)

摘要

PURPOSE: Provided is an advanced wastewater treatment method for removing nitrogen and phosphate simultaneously, which is characterized in that a Plug Flow Reactor separator(2) operated under anoxic state is adopted as a bio-adsorption basin, RIDs are installed in a nitrification basin(6), HBC or RID is installed in a stabilization basin(12) causing luxury-uptake of phosphates by microorganisms for shortening HRT and minimizing operation cost. CONSTITUTION: The system consists of: a PFR separator(2) in which return sludge(22) from a final settling basin(14) is adsorbed biologically under anoxic condition; a primary settling basin(4) in which liquid/solid separation of mixed liquor that is pretreated in the PFR separator is carried out; a nitrification basin(6) which supernatant separated in the primary settling tank and return sludge(18) from the final settling tank flow into, and ammonia is oxidized to nitrite by RIDs; a preliminary anoxic basin(8) into which return sludge(20) from the final settling tank and sedimental sludge separated in the primary settling tank flow, so that NOx-N contained in the return sludge is denitrified and microorganisms release excess phosphate from their cell tissues to mixed liquor; an anoxic basin(10) in which nitrified supernatant flowed from the nitrification tank and denitrified mixed liquor flowed from the preliminary anoxic basin are mixed, and then complete denitrification is carried out; a stabilization basin in which remaining organics and ammonia are completely oxidized, and also luxury up-take of phosphates into cell tissues of microorganisms happens; the final settling basin in which microorganism sludge is settled for return sludge(22, 18, 16) and excess sludge is discarded. In this system, PSA(Pressure Swing Adsorption) type oxygen generator is optionally installed in the stabilization basin for increasing oxygen transmission efficiency so that HRT is reduced drastically and deodorizing effect can be accompanied. Further, in front of either the final settling basin or the PFR separator, chemical coagulants such as Al3+, Fe3+ are optionally injected to accelerate flocculation and remove soluble phosphates so that the primary settling basin can be operated stably.