This study performed the feasibility of reusing of ultrasonically treated waste sludge as carbon source for the biological dentirification process and also, confirmed the possibility of the reducing the sludge production in biological wastewater treatment process by return into the anoxic tank after a ultrasonic solubilization. Comparing the characteristics of effluent at each process in biloigical continuous systems between A series with injection of ultrasonic solubilizatin. Comparing the characteristics of effluent at each process in biological continuous systems between A series with injection of ultrasonic treated sludge to anoxic tank and B series with the conventional process. In spite of ultrasonically treated sewage sludge adding, the characteristics of the effluent were similar to the case of conventional process. The SDR(Specific denitrification rate) were obtained 1.07㎎ NO₂^(-) N/㎎ MLVSS day in A series, and 0.95 ㎎ NO₃^(-) N/㎎ MLVSS·day in B series. And the nitrification rate in aerobic tank was gained 1.53㎎ N/L-hr in A series and 0.94 ㎎ N.L-hr in B series.

본 연구는 하수처리장에서 발생되는 잉여 슬러지를 초음파를 이용하여 가용화한 후 무산소조로 반송시켜 생물학적 탈질 탄소원으로서의 재이용 가능성과 슬러지 감량화 가능성을 조사하였다. 초음파 처리된 슬러지를 주입한 A계열과 기존 처리공정인 B계열의 생물학적 연속공정을 비교ㆍ분석했을 때, 초음파 처리된 슬러지의 첨가에 따른 처리수질의 변동 없이 두 계열 모두 유사한 수질 특성을 나타내었다. 초음파 처리된 슬러지를 주입한 A계열의 비탈질율은 1.07 mg NO₃^(-)-N/mg MLVSSㆍday로 B계열의 0.95 mg NO₃^(-)-N/mg MLVSSㆍday보다 탈질율이 13% 증가하였으며, 폭기조에서의 질산화율도 A계열은 1.53 mg N/L-hr로 B계열의 0.94 mg N/L-hr보다 63% 높게 나타났다.