적조예방을 위한 ASA시스템의 도입 가능성에 관한 연구

A study on the Applicable Possibility of ASA System to repress the accurrence of Red-Tide

  To prevent from algal-bloom and red tide outbreak this study was focussed on Biological Nutrient Removal using the novel BNR system, Advanced Step Aeration(ASA) system, which could cope with not only a low level of municipal wastewater but also a high strength of apartment wastewater. Nutrient removals through ASA system were considerably excelent: at influent levels of T-N 40～80㎎/l, T-P 4.0～8.0㎎/l, respectively, removal efficiencies for T-N and T-P are 70～85% and 90% and effluent level for T-N and T-P are 10～15㎎/l and 0.4～0.6㎎/l. On the basis of 13 ℃, nitrification rate(KN) in aerobic tank was calculated to be 0.892 ㎎N/gMLSSㆍhr. Denitrification rate(KDN) according to C/N ratio from 3.68 to 4.3 and temperature from 13 to 18 ℃ was linearly increased and presented to be from 0.64 to 0.95 ㎎N/gMLSSㆍhr. Step-feeding raw wastewater to anaerobic and anoxic tank and using raw wastewater as external carbon source have brought about the improvement of denitrification capacity. Anoxic sludge tank minimized the nitrite and nitrate inhibition in the return activated sludge and maximized phosphorus release through the stable DO control.