Abstract

In this study, it was investigated the effect intermittent aeration and step-feed on nitrogen removal by providing anoxic-aerobic, anoxic-aerobic-anoxic-aerobic and step-feed anoxic-aerobic-anoxic-aerobic working conditions. Chemical oxygen demand (COD) removal efficiency was the same in all three working conditions and was found to be 91%. The NH4+-N removal efficiency is almost the same. The NH4+-N removal efficiencies in the W1, W2 and W3 are 92%, 93% and 95%, respectively. Total inorganic nitrogen (TIN) removal efficiency increased by 4% when intermittent aeration was applied. Increasing the efficiency of TIN removal by 24% was achieved by applying the step-feed intermittent aeration. Experimental results show that the effect of intermittent aeration on TIN removal was limited and that TIN removal performance with step-feed intermittent aeration was significantly increased.