Effects of effluent C/N ratio on pollutant removal performance in sequencing batch membrane bioreactor

By taking a sequencing-batch membrane bioreactor (SBMBR) which operated in anaerobic aerobic (AO) as the research object, the effects of influent C/N ratio on pollutant removal performance in this system have been investigated, when the influent C/N ratio was 17.3 ~ 18.5, the average removal rate of COD, ammonia nitrogen(NH₄⁺-N), total nitrogen(TN) and total phosphorus(TP) were 90.7%, 92.8%, 81.9% and 79.8%, respectively. When the influent C/N decreased to 8.6 ~ 10.3 , the average removal rate of NH₄⁺-N dropped to about 84% and was promoted to 93.5% by improving the aeration rate. At the same time, the average removal efficiency of COD, TN and TP were 90.7%, 81.9% and 79.8%, respectively. A problem worthy to be pointed out was that the average removal rate of TN could be increased to 83.9% by improving influent organic loading based on the influent C/N ratio of 8.6 ~ 10.3, while the removal efficiency of COD, NH₄⁺-N and TP were not impacted. The average removal rate of them were 92.5%, 93.5% and 76.9%, respectively. Results obtained from this study indicate that the C/N ratio of had no obvious effect on the removal of COD and TP in this system. And this system also have shown a better removal ability of nitrogen.