Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
Bioresour Technol. 2015;187:282-287. doi: 10.1016/j.biortech.2015.03.063. Epub 2015 Mar 19.
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.
为研究碱化问题及其对高负荷反硝化系统的潜在影响，考察了操作模式对高负荷反硝化反应器自碱化的影响。结果表明，基质浓度的增加和水力停留时间（HRT）的缩短均能引起高负荷反硝化反应器（氮负荷（NLR）高于 25kg Nm(-3)d(-1)）显著的自碱化。当进水 pH 值为 7.0±0.1 时，出水 pH 值超过 9.20。反硝化过程的自碱化源于硝酸盐还原，而甲醇氧化可以通过中和 OH(-)和建立 HCO3(-)/CO3(2-)缓冲体系来缓解自碱化。在相同的 NLR 下，由基质浓度增加引起的自碱化作用明显强于由 HRT 缩短引起的自碱化作用。将硝酸盐浓度保持在抑制浓度以下可改善高负荷反应器的性能并缓解自碱化作用。
