LIHang,DONGLi-chun,LüLi-ping.Enhanced Biological Nitrogen Removal Performance of Low Carbon to Nitrogen Ratio Wastewater[J].China Water & Wastewater,2022,38(7):80-85.
Enhanced Biological Nitrogen Removal Performance of Low Carbon to Nitrogen Ratio Wastewater
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第38卷
Number:
第7期
Page:
80-85
Column:
Date of publication:
2022-04-01
- Keywords:
- low C/N ratio wastewater; biological nitrogen removal; internal reflux ratio; dissolved oxygen（DO）; external carbon source; nitrogen
- Abstract:
- A modified A2/O process was employed to treat municipal wastewater with low carbon to nitrogen ratio (C/N), and the effects of internal reflux ratio and dissolved oxygen (DO) on biological nitrogen removal in an engineering project were investigated. On this basis, addition of carbon source was adopted to enhance nitrogen removal. Appropriately increasing the internal reflux ratio was beneficial to improve the total nitrogen removal efficiency. However, too high internal reflux ratio would increase the DO in the anoxic zone, which was not conducive to denitrification. The decrease of DO was beneficial to the removal of total nitrogen. However, it would inhibit the nitrification reaction in the aerobic zone, which affected the transformation of ammonia nitrogen. Among the five internal reflux ratios and five DO operating conditions, the optimal internal reflux ratio and DO were 275% and 1.2-1.5 mg/L. With the aid of dosing carbon source, the average concentration of total nitrogen in the effluent was reduced to 9.20 mg/L, and the average concentration of ammonia nitrogen was 0.38 mg/L, indicating that the effluent nitrogen indexes were significantly better than the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （GB 18918-2002）. The addition of carbon source did not have a significant impact on the effluent COD, and the contribution of additional carbon source to the cost was only 0.11 yuan/m3. In addition, a more robust control of the effluent index was achieved, which effectively promoted a win-win between cost and water quality.
Last Update:
2022-04-01