단축질소제거공정을 이용한 매립지 침출수의 처리

Abstract

A shortcut biological nitrogen removal (SBNR) process was tested to treat an ammonia rich (450~830 mgN/L) landfill leachate using a pilot-scale reactor. The SBNR process was intended to oxidize ammonia to nitrite and, then, to reduce it to nitrogen gas. The reactor consisted of an anoxic tanks (2 ㎡ in total), connected with liquid recycle at 2Q. The aerobic tanks contained suspended sponge media, making the reactors a suspended/attached-growth hybrid system. At HRT = 4~3 days, the aerobic tanks consistently accumulated nitrite, which was denitrified completely in the anoxic tank when recycled. The average ammonia oxidation efficiency was 90% and NO2--N/NOx-N ratio was 0.46. The average free ammonia concentration in the main ammonia oxidation tank was 3.7 mg/L. The CODCr removal efficiency was 88%, giving an quite consistent effluent concentration of 409 mg/L on average. the specific consumption of COD for denitrification, ?CODCr/?NOx-N, was 4.23. The value was higher than the theoretical value, but 33% lower than that observed during a complete nitrification (ammonia to nitrate) period in the same reactor. This implied that a SBNR process can save external carbon source when an internal supply in not sufficient of a post-denitrification is adopted.