Nitrogen Removal With Sequencing Batch Biofilm Reactor (SBBR) From Domestic Wastewater

In recent years, although there were a lot of municipal wastewater treatment plants built in China, the wastewater treatment rate was 58% in urban and 4% in country by the end of 2007. According to the China Environmental State Bulletin, surface water pollution was still serious, the seven water systems in China were moderately pollutted, and water eutrophication was the biggest problem. The water body which affected by nitrogen and phosphorus had expanded year by year. Thus, developing simple, high efficiency and low energy consumption wastewater treatment technique was the necessary to solve the problem of water pollution and shortage, and wastewater treatment techniques aimed at middle-small point pollution is the key research issue.Sequencing Batch Biofilm Reactor (SBBR) was studied. Soft fiber stuffing was selected as the bacteria carrier, and novel SBBR was operated with intelligent control system, the influence of initial COD and DO concentration on NH3-N and TN was studied. It was showed that, DO=4 mg/L is the best condition for nitrogen removal, TN removal efficiency was more than 95%. Optimum aeration and anaeration time of SBBR without intelligent control was determinted by sampling COD, NH₃-N, NO₃^--N, NO₂^--N and TN every 1 hour. Compared with continuously operating mode of SBBR, sequencing batch mode has better performance.The primary nitrogen removal mechanism of intelligent SBBR was researched based on COD, NH₃-N and TN removal efficiency, optimum low-limited DO value was 1 mg/L. For ordinary municipal wastewater, NH3-N was lower than 15 mg/L after 3-hour reaction, and it could be totally removed after 4 hours; TN in effluent was less than 5 mg/L, removal efficiency was 88%, the effluent quality was fit to the primary Urban Sewage Treatment Plant Pollutant Discharge Standards (GB18918-2002). Behavior of NO_x^--N and pH during the reaction was analyzed. Compared with the other treatment processes and SBBR without intelligent control, intelligent SBBR had better performance, less react time and low energy consumption, and it can be used in practical engineering.