하향류식 단층 모래여과 장치를 이용한 접촉산화조 처리수의 중수도 활용 방안에 관한 연구

A Study on the Utilization of Water Recycling System Using Upflow Sand Filter for the Wastewater Treated by Contact Oxidation Process

  본 연구는 날로 심각해져 가는 물 부족에 따른 대안이라고 생각되는 중수도 system에 있어서, 비용절감의 효과가 크다고 예상되는 하향류식 단층 모래여과 장치를 부착하여 중수도 활용 가능성을 연구하였다. 접촉산화조에서 처리된 처리수를 침전조에서 채취하였으며 이를 실험 원수로 사용하였다. 모래여과 단독처리와 모래여과 후 염소소독한 처리수의 BOD 농도와 대장균수 등을 측정 비교하였다. 모래여과 단독처리시 BOD 농도는 14~20 ㎎/L, 대장균수는 80~90% 감소하였고, 모래여과 후 염소소독의 경우 대장균은 염소 농도 0.2㎎/L이상에서는 검출되지 않았으며, 염소 농도 0.1 ㎎/L에서 569 (MPN) cells/100 mL로 검출되었다. 모래여과 후 염소소독한 처리수의 BOD 농도 변화는 염소 농도 1㎎/L당 BOD 농도 1~2 ㎎/L (평균 1.5 ㎎/L) 정도가 감소하였고, 염소농도가 0.4 ㎎/L이상 되도록 염소를 주입할 경우, 잔류염소 농도가 0.2㎎/L이상 존재하고 유리잔류염소 농도도 0.1 ㎎/L이상 존재하였다.

  The water recycling system is an alternative plan of the shortage of water. This study on the utilization of water recycling system using upflow sand filter is expected that the effect of cost-cutting is big, is made. The wastewater treated by contact oxidation process was sampled in settling tank and used as the influent of this experiment. BOD concentration and the number of coliform etc. in effluent after sand filtration process and after process equipped by sand filter and chlorine contact tank, was measured and compared. When the wastewater was treatment by sand filter, BOD concentration was 14~20 ㎎/L, and the number of coliform reduced 80~90%. When the wastewater was treated by sand filtration and chlorine injection, coliform was not detected above 0.2 ㎎/L of chlorine concentration, and it was detected by 569 (MPN) cells/100 mL in 0.1 ㎎/L of chlorine concentration. After sand filtration and disinfection with chlorine, 1~2 ㎎/L (average 1.5 ㎎/L) of BOD concentration per 1 ㎎/L of chlorine concentration was decreased. When above 0.4 ㎎/L of chlorine concentration was injected, the more of 0.2 ㎎/L of residual chlorine concentration and above 0.1 ㎎/L of free residual chlorine concentration existed.