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Denitrification behavior and microbial community spatial distribution inside woodchip-based solid-phase denitrification (W-SPD) bioreactor for nitrate-contaminated water treatment

Zhao, Jiamin, Feng, Chuanping, Tong, Shuang, Chen, Nan, Dong, Shanshan, Peng, Tong, Jin, Shunlong
Bioresource technology 2018 v.249 pp. 869-879
ammonium, bacteria, bioreactors, denitrification, denitrifying microorganisms, enzyme kinetics, high-throughput nucleotide sequencing, logit analysis, microbial communities, models, nitrate reduction, nitrates, water treatment
The NO3− removal pathway and microorganisms change along with the height of an up-flow W-SPD bioreactor was investigated in this study. Modeling and microbial community analysis were used to analyze the denitrification behavior in W-SPD bioreactor. The results showed that NO3− removal rate matched for zero-order (R2 > 0.97) and first-order (R2 > 0.94) combination Michaelis-Menten kinetics, whereas microbial reaction rate suited for modified logistic model (R2 > 0.99). The excellent denitrification performance (92.5%–96.4%) and microorganisms’ quantity occurred in the middle of W-SPD bioreactor. Moreover, high-throughput sequencing analysis revealed that dominant denitrifiers, carbonaceous compound degrading bacteria and fermentative bacteria co-existed in W-SPD system, which was vital for efficiently sustainable NO3− removal. Hence, aerobic degradation, heterotrophic denitrification and dissimilatory nitrate reduction to ammonium (DNRA) occurred successively along the water direction in the bioreactor, offering reasonable references for W-SPD bioreactor study and application.