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在北卡罗来纳州 Rocky Point 镇附近为了研究含水层内在生物净化作用的标志,识别对生物净化作用的速率和强度有重要影响的一些因素,我们对受汽油污染的含水层进行了详细的调查。结果发现,溶解在地下水中的苯、甲苯、苯乙烯和二甲苯(BTEX)自然降解,其中甲苯、邻-二甲苯降解速率很快,然后是间-二甲苯、对-二甲苯和苯,而在污染水流中心厌氧条件下,苯乙烯降解速率则很慢。生物降解的速度和强度强烈地受含水层中氧化剂类型和数量的影响。在污染水流的上游边界硝酸盐、铁离子和氧气是碳氢化合物降解的最终电子受体。由于40～50mg/L碳氢化合物的降解,导致地下水中二氧化碳含量的升高。紧靠污染源区下游,硫酸根和铁离子是主要的电子受体。在这区域,甲苯和邻-二甲苯很快被氧化。一旦有可利用的氧气,硝酸根和硫酸根被消耗掉,生物降解就受到限制。表现为在污染水流的边部发生需氧和厌氧共存的或需氧的生物降解。
Near Rocky Point, North Carolina In order to study the hallmark of intrinsic biological purification in aquifers and to identify a number of factors that have a significant impact on the rate and strength of biological purification, we conducted a detailed investigation of gasoline-contaminated aquifers. As a result, it was found that benzene, toluene, styrene and xylene (BTEX) dissolved in the groundwater spontaneously degrade, wherein toluene, o-xylene rapidly degrade, and then meta-xylene, para-xylene and benzene, Under anaerobic conditions at the contaminated water stream, styrene degrades slowly. The rate and intensity of biodegradation is strongly influenced by the type and amount of oxidant in the aquifer. Nitrate, iron and oxygen are the ultimate electron acceptors for the degradation of hydrocarbons at the upper boundary of contaminated water. Due to 40 ~ 50mg / L of hydrocarbon degradation, resulting in increased groundwater carbon dioxide levels. Immediately downstream of the source area, sulfate and ferric ions are the major electron acceptors. In this area, toluene and o-xylene are quickly oxidized. Once available oxygen, nitrate and sulfate are consumed, biodegradation is limited. Manifested as aerobic and anaerobic coexistence or aerobic biodegradation at the edge of contaminated water.