Research Of MBBR Used In Pilot-Scale And Full-Scale For Treating Municipal Wastewater In Middle And Low Temperature

As the rapid development of industry, the sharp increasing of population and the improvement of the standards of living, the want for water is also rapidly increasing. However, it is serious that the water quality in China is deteriorating, which is in correlation with low removal efficiency of municipal wastewater, low efficiency of meeting the State's discharge standards and exceeding in the total pullutants discharge. So it is necessary to improve the discharge standard and removal efficiency of municipal wastewater, and reclaim water reuse for keeping sustainable development of water resource. But it is difficult to meet the new standard, expecially the standard of denitrification and phosphorus removal for many wastewater treatment plants built in the twentieth century.The effect of operation of the process of MBBR and A/O used in pilot-scale and the practical transforming project in the Yingkou wastewater treatment plant was studied. It was concentrated on the removal of pullutant in middle and low temperatue, which is lower than 15℃.Firstly, the oxygenation capacity of the BioMTM Suspended Carriers was researched in small-scale and it was determinated that the rational holdup was 40% by considering economy. Secondly, Oxygen Demonad (DO) and influent quantity were changed in the two-stage MBBR process in pilot-scale. It was concentrated on the removal of nitrogen in middle and low temperatue. The results shows that COD, NH4+-N, TN in effluent all can meet or approach the 1th A standard in low temperature between 5℃and 12℃, HRT of 7.2h, DO of 3~4mg/L and 1~2mg/L in the two parts of the reator, surface organic loading of 1.76gTN/(m2·d), surface NH4+-N's loading of 1.4gNH4+-N/(m2·d), surface TN's loading of 1.4gTN/(m2·d). It was testified that it was possible to achive stable SND. On the operation of this process, in the process of MBBR and A/O in microblending which made use of the character of ABR, the effect of denitrification and phosphorus removal were studied in small stirring intensity in anaerobic reactor by changing the value of reflux ratio and influent quantity. The results indicated that COD, NH4+-N, TN in effluent all can meet the 1th A standard in low temperature that was lower than 12℃, HRT of 8.7h, reflux ratio of 70%.The effect of operation of the process of MBBR and A/O used in the practical transforming project in the Yingkou wastewater treatment plant was studied. The influence of temperature and holdup on denitrification and phosphorus removal were expecially invested. The results showed that COD, NH4+-N in effluent all can meet the 1th A standard in low temperature that was lower than 12℃, HRT of 7h, reflux ratio of 70%; TN in effluent all can meet the 1th A standard in low temperature with HRT of 8h; the effect of phosphorus removal was well in organic loading of 0.22kgBOD5/(kgMLSS·d), the ratio of BOD5/TP of 48. It indicated that this transforming process was better than the traditional process of activated sludge. Finally, some problems and their solutions of MBBR that was in plug flow were pointed out.