Investigation On The Factors Effected On Performance Of An Intelligent Controlled Sequencing Batch Biofilm Reactor

With the development of economy and improvement of life conditions, the discharge of municipal wastewater gradually exceeded that of industrial wastewater. On the contrary, the standardized emission rate of municipal wastewater was much lower than that of industrial wastewater, making it the most important sources of pollution.There are many methods used in municipal treatment and the traditional activated sludge process is the most popular one. Recently, a new treatment process, sequencing batch biofilm reactor, is developed based on the conventional activated sludge process and biofilm reactor. For the greater biomass, strength capacity of resisting shock loading and small area, sequencing batch biofilm reactor (SBBR) has been used to treat municipal wastewater and some special industrial wastewaters. As an essential factor, the operation strategy plays an important role during the operation of SBBR. A newly developed intelligent controlling system (ICS) was adopted to control the SBBR in this work. A special kind of biological sponge with high porosity was served as biofilm carrier and the performance factors of the SBBR in treating municipal wastewater was investigated, including operation cycle and influent C/N.After 30 days' operation, the removal efficiencies of NH3-N and COD kept still and reached 97.8% and 97.5%, respectively. The biofilm was formed at the day of 40. In addition, the influence of influent C/N ration on the performance was also observed. After that, the operation cycle was optimized and the result showed that the HRT of 7 hours was most optimal and economical for the pollutants removal. The average removal efficiencies of NH3-N, TN, TP and COD reached 98.9%,86.0%,99.6% and 95.7%, respectively, and all the pollutants concentrations in effluent met the first level A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002).Besides, the effect of influent C/N ratio on performance of the SBBR during normal operation also was investigated. It was demonstrated that the best performance was achieved at the C/N ratio of 12.5. The removal efficiencies of NH3-N, TN and COD reached 90.1%, 87.4% and 94.8%, and the efficiency of simultaneous nitrification and denitrification (SND) up to 97.9%. When compared with conventional SBBR controlled by PLC, the SBBR controlled by the ICS reduced the HRT and total aeration time by 56% and 50%, respectively, and achieved better performance at removing the COD.All above, these findings indicated that the SBBR controlled by the ICS showed promise for the effective treatment of municipal wastewater. The best HRT of the ICS-SBBR was 7 hours the best influent C/N ratio was 12.5 during this study.