title: Effects of operation mode on self-alkalization of high-load denitrifying reactor.
abstract: To study the alkalization issue and its potential effects on high-load denitrifying system, the effects of operation mode on self-alkalization of high-load denitrifying reactor were investigated. The results showed that both the increase of substrate concentration and decrease of hydraulic retention time (HRT) can induce notable self-alkalization of high-load denitrification reactor (with the nitrogen loading rate (NLR) higher than 25kg Nm(-3)d(-1)). The effluent pH surpassed the 9.20 when the influent pH value was 7.0±0.1. The self-alkalization of denitrification process originated from the nitrate reduction, while the methanol oxidation could alleviate the self-alkalization by neutralizing OH(-) and setting up a buffering system of HCO3(-)/CO3(2-). At the same NLR, the self-alkalization induced by increase of substrate concentration was remarkably stronger than that induced by decrease of HRT. Keeping the nitrate concentration below inhibition concentration improved the performance of high-load reactor and alleviated the self-alkalization.
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors: Wei
authors: W
authors: Li
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors: Chenxu
authors: C
authors: Li
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors: Xiaoyu
authors: X
authors: Lin
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors: Yan
authors: Y
authors: Liu
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors: Ghulam
authors: G
authors: Abbas
authors: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China. Electronic address: pzheng@zju.edu.cn.
authors: Ping
authors: P
authors: Zheng
mesh_terms: D000468:Alkalies / Q000737:chemistry / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D058440:Denitrification / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D000468:Alkalies; D009566:Nitrates; D009584:Nitrogen
keywords: Denitrification; High-load reactor; Operation mode; Self-alkalization