Nitrogen removal from sewage by continuous flow SBR system with intermittent aeration

A continuous-now sequential batch reactor system with intermittant aeration known as the intermittent cycle extended aeration system was used to inves tigate the efficiencies of nitrogen removal for savage. In the conventional intermittent cycle extend aeration system with continuous aeration process to treat the synthetic savage wastewater under 3 cycles per day (cycle tim e = 8 hours), high COD removal efficiencies wee achieved, but high levels o f nitrate (22.3-23.6 mg l(-1)) and decreased pH values were also found in t he effluent In the intermittent aeration, the dissolved oxygen in the react or was reduced from the range of 3.5-5.0 mg l(-1) to 0.5 similar to1.2 mg l (-1), the nitrogen in the influent was partially oxidized to nitrite-nitrog en, although nitrate-nitrogen was also present in the effluent. In detailed cyclic study of the reactor with relatively low D.O. (0.3 similar to1.0 mg l(-1)) and high MLSS (3200 mg l(-1) at half full water level), the experim ental results of intermittent aeration processes showed higher oxidation ra tes of ammonia to nitrite (1.44 similar to3.55 mg N g(-1) MLSS hr(-1)) than the conversion rates of nitrite to nitrate (0.00 similar to1.22 mg N g(-1) MLSS hr(-1)). It was thus, concluded that denitrification rates were not a ffected by the limited supplement of soluble organic carbon in the system. In addition. NOx.-N could be removed with a total nitrogen removal rate up to 94.9 % when the MLSS was controlled in concentrations of 3200 mg l(-1) a t half full water level with tow DL). The process of intermittent aeration of ICEAS could provide an economic and effective means for nitrogen removal in treating sewage.