SEWAGE AND WASTEWATER TREATMENT SYSTEM AND METHOD USING SBR (SEQUENCING BATCH REACTOR) AND SLUDGE STORAGE-THICKENER

摘要

PURPOSE: Provided are a wastewater treatment system and a wastewater treatment method being capable of effectively and simultaneously removing nitrogen and phosphorous and obtaining stable water quality at short hydraulic retention time. CONSTITUTION: The system comprises a first and a second sequencing batch reactors(40',40'') and a first and a second sludge storage-thickeners(50',50''). The method comprises the steps of (a) settling sludge in a first sequencing batch reactor in which reaction has finished while anoxic and aerobic reactions of sludge drawn from a second sludge storage-thickener are performed in a second sequencing batch reactor, and discharging 50-60% of decant water, (b) discarding a portion of sludge settled in the first sequencing batch reactor, transferring the remainder of the sludge and the remainder of the decant water to the second sludge storage-thickener which is empty, and thickening the sludge in the second sludge storage-thickener, (c) returning the decant water of the second sludge storage-thickener to the first sequencing batch reactor, transferring the thickened sludge of the second sludge storage-thickener to the first sludge storage-thickener and causing anaerobic reaction in the second sludge storage-thickener to release phosphorous from the sludge, (d) after completion of the anaerobic reaction, transferring the settled sludge and raw wastewater to the first sequencing batch reactor to cause anoxic and aerobic reaction, and (e) repeating the steps (a)-(d) by switching the first and second sequencing batch reactor to each other and switching the first and second sludge storage-thickeners to each other.