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污染控制技术及原理

Reductive transformation and biodegradation of 2-chloronitrobenzene with a column of zero-valent iron coupled with a sequencing batch reactor

摘要：研究了零价铁(ZVI)固定床-序批式生物反应器(SBR)耦合工艺对2-氯硝基苯(2-ClNB)转化与降解强化作用.结果表明,ZVI固定床可稳定还原转化2-ClNB为2-氯苯胺(2-ClAn),表面积归一化速率常数(K_sa)为(3.20±0.35)×10^-2L·m^-2·h^-1;ZVI固定床出水作为SBR进水,在HRT为20h、2-ClAn负荷为3.6～111.8g·m^-3·d^-1、COD负荷(外加碳源)为130.9～854.4g·m^-3·d^-1条件下稳定运行SBR,其2-ClAn去除率达99.9%以上,COD去除率达92.3%±5.5%,2-ClAn污泥比降解速率达0.31g·g^-1·d^-1;耦合系统在不添加其它碳源、氮源条件下,TOC去除率达95.4%,总氮去除率为46.1%.而以未经ZVI预处理的2-ClNB为进水的SBR对照实验发现,2-ClNB去除率仅为25.3%±10.2%,主要以挥发形式去除.研究结果揭示,ZVI-SBR耦合工艺可强化氯代硝基苯类污染物的降解与矿化.

Abstract：The feasibility of enhancing 2-chloronitrobenzene(2-ClNB)degradation with a zero-valent iron(ZVI)column coupled with an aerobic sequencing batch reactor(SBR)was investigated in this study.2-ClNB was rapidly transformed into 2-chloroaniline(2-ClAn) in the ZVIcolumn with a surface area-normalized rate constant(k_sa)of(3.20±0.35)×10^-2 L·m^-2·h^-1.The transformed effluent of the ZVI column,diluted with nutrient medium,was fed into the SBR with a 2-Cl An loading of 3.6～111.8 g·m^-3·d^-1 and COD loading of 130.9～854.4 g·m^-3·d^-1 at a hydraulic residence time(HRT)of 20 h.Over 99.9% of 2-ClAn and 92.3%±5.5% of COD was removed once the coupled system ran stably on day 5.The sludge specific degradation rate of 2-ClAn was up to 0.31 g·g^-1·d^-1 for the SBR.The removal rates of TOCand total nitrogen were about 95.4% and 46.1%,respectively,when the coupled system was operated without adding other carbon and nitrogen sources.On the other hand,the removal rate of 2-ClNB in a control SBRwithout iron pretreatment was only 25.3%±10.2%,which was mainly attributed to volatilization of the pollutant.These results demonstrate that a coupled ZVI-SBR system may be a feasible approach to enhance biodegradation and mineralization of chloronitrobenzenes.

Key words：chloronitrobenzene zero-valent iron biodegradation coupling process