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Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation
Published on: July 13, 2012
Effects of operation mode on self-alkalization of high-load denitrifying reactor
Wei Li1, Chenxu Li1, Xiaoyu Lin1
1Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
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.
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