SUNXian-peng,MENGXue,LIUXu-yang,et al.Optimization for Uneven Water Distribution in MBBR with High Width-Length Ratio Based on Practical Engineering[J].China Water & Wastewater,2024,40(9):1-7.
Optimization for Uneven Water Distribution in MBBR with High Width-Length Ratio Based on Practical Engineering
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第40卷
Number:
第9期
Page:
1-7
Column:
Date of publication:
2024-05-01
- Keywords:
- moving bed biofilm reactor (MBBR); hight width-length ratio; short circuit; aeration distribution; tracer
- Abstract:
- The outlet of moving bed biofilm reactor (MBBR) with high width-length ratio is closely located to the inflow distribution channel, which leads to uneven distribution of inflow and outflow, resulting in a short circuit phenomenon, thereby affecting the pollutants removal. To fully utilize the treatment capability of the MBBR, this study focused on a MBBR with width-length ratio of 2.3∶1 in a wastewater treatment plant in Qingdao. Measures such as adjusting the internal reflux ratio, partially blocking the outlet, altering the operating conditions of the aeration system, and lowering the water level to form a waterfall in the distribution channel were implemented. These measures, while ensuring the oxygen transfer efficiency of the system, alleviated the short circuit phenomenon within the MBBR. The effectiveness of these measures was verified through water quality tests and tracer experiments. The results showed that under conventional operating conditions (200% internal reflux, 100% external reflux), the effluent ammonia nitrogen concentration in the MBBR gradually increased. Tracer test results confirmed the presence of a short circuit phenomenon within the system. When the external reflux ratio was kept constant and the internal reflux ratio was adjusted to 100% and 300%, the short circuit phenomenon within the MBBR improved. However,considering factors such as treatment effectiveness and operational energy consumption, neither of these conditions was recommended for use. After implementing the solution of partially blocking the outlet and adjusting the operating conditions of the aeration system, the difference in the oxygen transfer efficiency between the inlet and outlet cross-sections of the MBBR decreased,but that of the inflow increased. Therefore, the measure of further lowering the water level to form a waterfall in the distribution channel was introduced to ensure the uniformity of inflow. Tracer experiments confirmed that the process optimization measures effectively mitigated the short circuit phenomenon of the effluent under conventional operating conditions by addressing the issue of uneven distribution of inflow and outflow.
Last Update:
2024-05-01