北方地下水中铁和2,4,6-三氯苯酚氧化细菌对氧气的竞争

Competition for oxygen by iron and 2,4,6-trichlorophenol oxidizing bacteria in boreal groundwater.

作者信息

Langwaldt Jörg H, Puhakka Jaakko A

机构信息

Institute of Environmental Engineering and Biotechnology, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland.

出版信息

Water Res. 2003 Mar;37(6):1378-84. doi: 10.1016/S0043-1354(02)00480-3.

DOI:10.1016/S0043-1354(02)00480-3

PMID:12598200

Abstract

Kinetics of simultaneous iron and 2,4,6-trichlorophenol (TCP) oxidation by groundwater enriched cultures were studied in order to reveal the competition for oxygen in aerobic in situ bioremediation of boreal groundwater. Chemical iron oxidation at near neutral pH in synthetic groundwater depended by the first order on the concentrations of ferrous iron and dissolved oxygen and by the second order on pH. The chemical iron oxidation rate constant was on average 2.2 x 10(13)mol(-2)L(2)atm(-1)min(-1). Chemical iron oxidation was insignificantly affected by natural organic matter, 2,4,6-tri-, 2,3,4,6-tetra- or pentachlorophenol in groundwater. Biological oxidation of iron followed zero-order kinetics. At pH of 6.3 and dissolved oxygen (DO) concentration of 11.5 mgL(-1), the rate of biological iron oxidation was 3.8 x 10(-4)mmolL(-1)min(-1) and up to one order of magnitude higher than the chemical oxidation rate, 5.2 x 10(-6) mmolL(-1)min(-1). Biological oxidation of iron was completely inhibited by pentachlorophenol at 23 micro mol-1. With a groundwater enriched culture, oxygen was consumed at higher rates by 2,4,6-TCP oxidizers (2.5-7.6 x 10(-5)mmolDOL(-1)min(-1)) than the iron oxidizing bacteria (0.8-3.1 x 10(-5) mmolDOL(-1)min(-1)) at both low and saturated DO-concentrations. The results indicate that in situ iron oxidation is predominantly biogenic in the studied boreal aquifer. 2,4,6-TCP degrading bacteria consumed DO at higher rates than the iron oxidizing bacteria and thereby, favour bioremediation of the polychlorophenol contaminated groundwater.

摘要

为揭示北方地区地下水中好氧原位生物修复过程中氧气的竞争情况，研究了富集培养的地下水中铁与2,4,6 - 三氯苯酚（TCP）同时氧化的动力学。在合成地下水中近中性pH条件下，化学铁氧化反应对亚铁离子和溶解氧浓度呈一级依赖关系，对pH呈二级依赖关系。化学铁氧化速率常数平均为2.2×10¹³mol⁻²L²atm⁻¹min⁻¹。地下水中的天然有机物、2,4,6 - 三氯苯酚、2,3,4,6 - 四氯苯酚或五氯苯酚对化学铁氧化的影响不显著。铁的生物氧化遵循零级动力学。在pH为6.3且溶解氧（DO）浓度为11.5 mgL⁻¹时，生物铁氧化速率为3.8×10⁻⁴mmolL⁻¹min⁻¹，比化学氧化速率5.2×10⁻⁶mmolL⁻¹min⁻¹高一个数量级。五氯苯酚在23 μmol⁻¹时完全抑制铁的生物氧化。对于富集培养的地下水，在低DO浓度和饱和DO浓度下，2,4,6 - TCP氧化菌消耗氧气的速率（2.5 - 7.6×10⁻⁵mmolDOL⁻¹min⁻¹）均高于铁氧化细菌（0.8 - 3.1×10⁻⁵mmolDOL⁻¹min⁻¹）。结果表明，在所研究的北方含水层中，原位铁氧化主要是生物成因的。2,4,6 - TCP降解菌消耗DO的速率高于铁氧化细菌，因此有利于多氯苯酚污染地下水的生物修复。