Laboratory studies to characterize the efficacy of sand capping a coal tar-contaminated sediment
Laboratory studies to characterize the efficacy of sand capping a coal tar-contaminated sediment
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DOI：
10.1016/j.chemosphere.2005.10.025
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发表时间：
2006-06-01
期刊：
影响因子：
8.8
通讯作者：
Rao, P. Suresh C.
中科院分区：
文献类型：
--
作者：
Hyun, Seunghun;Jafvert, Chad T.;Rao, P. Suresh C.
在煤焦油污染的河流沉积物上放置一个微生物活性砂盖已被建议作为一种具有成本效益的修复策略。这一方法假定，来自沉积物的污染物通量与流入沙层的氧气和营养物通量充分平衡，因此微生物活动将降低新的底栖区内的污染物浓度，并减少污染物流入水柱。这样一个系统的动力学进行了评估，使用批和柱的研究与微生物群落焦油污染的沉积物在不同的曝气和营养物质的输入。在一个30天的批处理降解研究煤焦油沉积物的水提取物，氧气和营养物质的浓度被发现是控制多环芳烃（PAHs）的降解速率的关键参数。对于五个多环芳烃监测（萘，芴，菲，蒽，芘），降解率成反比的分子大小。对于柱研究，其中三个柱在5cm沉积物层的顶部填充有20 cm砂层，用（1）充气水、（2）N-2喷射水或（3）HgCl 2灭菌的N-2喷射水建立砂层的流动。稳态条件后，多环芳烃的浓度是最低的曝气柱，除了芘，其浓度与所有的流出物不变。这些实验室规模的研究支持，如果可以通过主动和被动方式在现场实现充分的曝气，所产生的微生物活性砂层可以改善底栖区的水质，并减少许多，但不是全部，多环芳烃的水柱通量。(c)2005爱思唯尔有限公司保留所有权利。
Placement of a microbial active sand cap on a coal tar-contaminated river sediment has been suggested as a cost effective remediation strategy. This approach assumes that the flux of contaminants from the sediment is sufficiently balanced by oxygen and nutrient fluxes into the sand-layer such that microbial activity will reduce contaminant concentrations within the new benthic zone and reduce the contaminant flux to the water column. The dynamics of such a system were evaluated using batch and column studies with microbial communities from tar-contaminated sediment under different aeration and nutrient inputs. In a 30-d batch degradation study on aqueous extracts of coal tar sediment, oxygen and nutrient concentrations were found to be key parameters controlling the degradation rates of polycyclic aromatic hydrocarbons (PAHs). For the five PAHs monitored (naphthalene, fluorene, phenanthrene, anthracene, and pyrene), degradation rates were inversely proportional to molecular size. For the column studies, where three columns were packed with a 20-cm sand layer on the top of a 5 cm of sediment layer, flow was established to sand layers with (1) aerated water, (2) N-2 sparged water, or (3) HgCl2-sterilized N-2 sparged water. After steady-state conditions, PAH concentrations in effluents were the lowest in the aerated column, except for pyrene, whose concentration was invariant with all effluents. These laboratory scale studies support that if sufficient aeration can be achieved in the field through either active and passive means, the resulting microbially active sand layer can improve the water quality of the benthic zone and reduce the flux of many, but not all, PAHs to the water column. (c) 2005 Elsevier Ltd. All rights reserved.