JIFei,BIANYong-huan,ZHAOFeng,et al.Effect of Different Upflow Velocity Promotion Strategy on the Performance of Denitrifiying Granular Sludge Reactor[J].China Water & Wastewater,2022,38(23):7-16.
Effect of Different Upflow Velocity Promotion Strategy on the Performance of Denitrifiying Granular Sludge Reactor
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第38卷
Number:
第23期
Page:
7-16
Column:
Date of publication:
2022-12-01
- Keywords:
- upflow velocity; denitrification granular sludge; extracellular polymeric substance; microbial community
- Abstract:
- In order to explore the influence of different upflow velocity amplitudes on the denitrification granular sludge (DGS) reactor, both rapid rise reactor (increasing the upflow velocity with a high rate, denoted as RH) and slow rise reactor (increasing the upflow velocity with a low rate, denoted as RL) was constructed. The impact of different upflow velocity promotion strategies on the performance of the reactor was investigated, and the characteristics of the DGS and the bacterial flora was analyzed. The results showed that when the upflow velocity of the RH and RL reactors was increased from 0.25 m/h to 0.41 m/h, the average removal rates of NO3--N and COD were over 92%, the average accumulation of NO2--N was about 1.5 mg/L; when the upflow velocity of the RH and RL reactors was further increased to 0.49 m/h, the sludge in RH ran off, the COD removal rate dropped to about 73.1% in the first 5 days of operation, the average accumulation of NO2--N reached 16.3 mg/L, and the diameter of particles less than 1.4 mm increased from 34% to 51.8%; the average removal rate of NO3--N and COD and the average accumulation of NO2--N in the RL had little change. Meanwhile, the TB-EPS of granular sludge in the two reactors had different variation trend at this stage, the TB-EPS content of the sludge in the RL reactor increased from (32.4±0.8) mg/g to (56.2±0.4) mg/g, while that in RH decreased from (47.1±0.8) mg/g to (28.9±0.9) mg/g. TB?EPS played an important role in maintaining a relatively stable structure of DGS. High-throughput sequencing showed that Firmicutes and Planctomycetes, which were conducive to denitrification at the phylum level, were enriched in the RL reactor, but decreased in the RH reactor; the proportion of Hyphomicrobium, which was mainly involved in denitrification at the genus level, decreased significantly in the RH. The different variation of the microbial community in the two reactors caused the difference in the stability of the denitrification performance. Therefore, within the range of upflow velocity investigated in this study, the upflow velocity increase strategy of the RL is more conducive to the denitrification granular sludge withstanding higher upflow velocity and maintaining the stable operation of the reactor.
Last Update:
2022-12-01