Analysis of Denitrification Efficiency of a Wastewater Treatment Plant in South China Enhanced by MBBR
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第36卷
Number:
7 7
Page:
101-107
Column:
Date of publication:
2020-04-01
- Keywords:
- MBBR; biological denitrification; simultaneous nitrification and denitrification; suspended carrier
- Abstract:
- The design scale of a wastewater treatment plant (WWTP) in Zhejiang Province was 16×104 m3/d. After retrofitted by Bardenpho-MBBR, the effluent COD, NH4+ - N, TN and TP of the WWTP were 17.2 mg/L, 0.37 mg/L, 7.72 mg/L and 0.168 mg/L, respectively. Without carbon addition, the effluent almost achieved class Ⅳ level of Environmental Quality Standards for Surface Water, which indicated that good biological nitrogen and phosphorus removal were obtained. According to the measurement of every functional area of the biochemical tank, 28%-46% of TN was removed in the aerobic area of the MBBR, and the removal efficiency could be maintained between 15% and 22% after the shock of muddy water. The good TN removal efficiency was benefited from simultaneous nitrification and denitrification (SND) in the MBBR zone. Due to the SND phenomenon in the aerobic zone, the carbon source cost could be saved by 0.23 yuan/m3 on average, and the annual carbon source cost could be saved by 13.432 million yuan. Control of biofilm thickness and dissolved oxygen had an important effect on stable performance of SND. Highthroughput sequencing of microorganisms in the system showed that the relative abundances of nitrifying bacteria and denitrifying bacteria on the suspended carrier were 32.19% and 4.86%, respectively. The simultaneous presence of nitrifying bacteria and denitrifying bacteria made SND phenomenon possible to happen. When the temperature was low in winter, nearly 90% of the nitrification load of the system was actually consumed by the suspended carrier.
Last Update:
2020-04-01