Abstract
A method for simultaneous removal of nitrogen and phosphate from sewage by elemental sulfur denitrification with membrane bioreactor was proposed, and capacity $10\;m^3$/day of pilot plant was operated for 350 days. This study was investigated to have the effect of denitrification rate and T-P removal with the addition of Alum in Sulfur denitrification Reactor (SDR). The addition of Alum and alkalinity ($NaHCO_3$) in the effluent of MBR was tried to remove simultaneous phosphate and nitrogen in SDR. Characteristics of total nitrogen (T-N) and total phosphate (T-P) removal was compared without and with the addition of Alum as a coagulant. T-N removal without and with the addition of Alum was 92.1% and 87.8%, respectively. And denitrification efficiency was 93.8% and 87.1%, respectively. T-P removal rate was increased to 75.6% in SDR by addition of Alum (2.6~4 mg/L as Al), but T-P removal rate was about 26.7% without the addition of Alum. Therefore, denitrification rate was 6.7% of reduction but T-P removal rate was increased by addition of Alum.
하수의 질소 인 동시 제거를 위해 MBR 공정과 SDR 공정순으로 구성하여 처리용량 $10\;m^3$/일의 pilot plant를 약 350일 동안 운전을 하였다. MBR 유출수에 알칼리도($NaHCO_3$)와 응집제(Alum)를 일정한 농도로 주입하여 황 탈질 공정에서 질소 인을 동시에 제거하기 위해 인 제거와 탈질효율에 대한 영향을 조사하였다. MBR 유출수에 응집제를 주입 여부에 따라 SDR 공정에서의 T-N 제거율은 92.1%와 87.8%로 각각 나타났으며, 탈질율은 93.8%와 87.1%로 각각 나타났다. T-P 제거율은 응집제를 주입하지 않고 실험한 결과 약 26.7%로 나타났지만, Alum 2.6~4 mg/L (as Al)를 연속적으로 주입하여 실험한 결과에서 75.6%의 T-P 제거율이 나타났다. 따라서 응집제를 주입함에 따라 SDR 공정에서 탈질효율은 약 6.7% 정도 감소하였으며, 인 제거율은 증가되는 것으로 나타났다.