Pavelic Paul, Nicholson Brenton C, Dillon Peter J, Barry Karen E
CSIRO Land and Water, PMB 2, Glen Osmond, SA 5064, Australia.
J Contam Hydrol. 2005 Mar;77(1-2):119-41. doi: 10.1016/j.jconhyd.2004.12.003.
Knowledge on the behaviour of disinfection by-products (DBPs) during aquifer storage and recovery (ASR) is limited even though this can be an important consideration where recovered waters are used for potable purposes. A reclaimed water ASR trial in an anoxic aquifer in South Australia has provided some of the first quantitative information at field-scale on the fate and transport of trihalomethanes (THMs) and haloacetic acids (HAAs). The results revealed that THM half-lives varied from <1 to 65 days, with persistence of chloroform being highest and bromoform lowest. HAA attenuation was rapid (<1 day). Rates of THM attenuation were shown to be highly dependent on the geochemical environment as evidenced by the 2-5 fold reduction in half-lives at the ASR well which became methanogenic during the storage phase of the trial, as compared to an observation well situated 4 m away, which remained nitrate-reducing. These findings agree with previous laboratory-based studies which also show persistence declining with increased bromination of THMs and reducing redox conditions. Modelling suggests that the chlorinated injectant has sufficient residual chlorine and natural organic matter for substantial increases in THMs to occur within the aquifer, however this is masked in some of the field observations due to concurrent attenuation, particularly for the more rapidly attenuated brominated compounds. The model is based on data taken from water distribution systems and may not be representative for ASR since bromide and ammonia concentrations in the injected water and the possible role of organic carbon in the aquifer were not taken into consideration. During the storage phase DBP formation potentials were reduced as a result of the removal of precursor material despite an increase in the THM formation potential per unit weight of total organic carbon. This suggests that water quality improvements with respect to THMs and HAAs can be achieved through ASR in anoxic aquifers.
尽管在回用水用于饮用目的时，消毒副产物（DBPs）在含水层储存与回灌（ASR）过程中的行为是一个重要考量因素，但目前对此的了解仍然有限。在南澳大利亚一个缺氧含水层中进行的再生水ASR试验，首次提供了一些关于三卤甲烷（THMs）和卤乙酸（HAAs）在现场规模下的归宿和迁移的定量信息。结果显示，THM的半衰期从小于1天到65天不等，其中氯仿的持久性最高，溴仿最低。HAA的衰减很快（<1天）。THM的衰减速率高度依赖于地球化学环境，试验储存阶段期间变为产甲烷环境的ASR井处的半衰期降低了2至5倍，相比之下，距离4米远的一口观测井仍处于硝酸盐还原环境，这证明了这一点。这些发现与之前基于实验室的研究一致，这些研究也表明，随着THMs溴化程度的增加和氧化还原条件的降低，其持久性下降。模型表明，氯化注入剂具有足够的余氯和天然有机物，足以使含水层内的THMs大幅增加，然而在一些现场观测中，这种增加被同时发生的衰减所掩盖，特别是对于衰减更快的溴化化合物。该模型基于取自供水系统的数据，可能不适用于ASR，因为未考虑注入水中的溴化物和氨浓度以及含水层中有机碳的可能作用。在储存阶段，尽管单位重量总有机碳的THM生成潜力增加，但由于前驱物质的去除，DBP生成潜力降低。这表明通过在缺氧含水层中进行ASR，可以实现THMs和HAAs方面的水质改善。
