1,4-二恶烷的存在和释放到现场废水处理系统(OWTS)的地下水中,占美国废水处理总量的25%,到目前为止还没有研究过。在这项研究中,我们监测了六个化粪池流出物(STE)中的1,4-二恶烷,并接收了长岛(LI)住宅中安装的OWTS,NY,为期15个月。我们特别评估了除氮生物过滤器(NRBs)作为创新/替代OWTS的性能,由顶部砂层和底部木片/砂层组成,同时除去氮和1,4-二恶烷。STE中的1,4-二恶烷含量(平均值:1.49μgL-1;范围:0.07-8.45μgL-1;n=37)平均比这些住宅的自来水高>15倍,证明1,4-二恶烷主要来自家用产品的使用。NRB可有效去除1,4-二恶烷和总氮,总去除效率为56±20%和88±12%,分别。大部分1,4-二恶烷去除(~80%)发生在NRB的顶部含氧层中。功能基因的检测(dxmB,prmA,和thmA),编码代谢和共代谢1,4-二恶烷降解,在NRBs中提供了废水系统中发生的1,4-二恶烷的好氧微生物降解的第一个现场证据。鉴于LI上有约500,000个常规OWTS,从住宅废水中排放到地下水的1,4-二恶烷估计为195±205kgyr-1,表明污染浅层含水层的风险很高。结果还表明,NRB的安装可以将1,4-二恶烷降低到甚至低于纽约州饮用水标准1μgL-1的水平。
The presence and release of 1,4-dioxane to groundwater from onsite-wastewater treatment systems (OWTS), which represent 25% of the total wastewater treatment in the U.S., has not been studied to date. In this study we monitored 1,4-dioxane in six septic tank effluents (STE) and receiving OWTS installed at residences on Long Island (LI), NY, for a period of 15 months. We specifically evaluated the performance of Nitrogen Removing Biofilters (NRBs) as an innovative/alternative-OWTS, consisting of a top sand layer and a bottom woodchip/sand layer, to simultaneously remove nitrogen and 1,4-dioxane. 1,4-Dioxane levels in STE (mean: 1.49 μg L-1; range: 0.07-8.45 μg L-1; n = 37) were on average > 15 times higher than tap water from these residences, demonstrating that 1,4-dioxane primarily originated from the use of household products. NRBs were effective in removing both 1,4-dioxane and total nitrogen with an overall removal efficiency of 56 ± 20% and 88 ± 12%, respectively. The majority of 1,4-dioxane removal (~80%) occurred in the top oxic layer of the NRBs. The detection of functional genes (dxmB, prmA, and thmA), which encode for metabolic and co-metabolic 1,4-dioxane degradation, in NRBs provides the first field evidence of aerobic microbial degradation of 1,4-dioxane occurring in a wastewater system. Given that there are ~500,000 conventional OWTS on LI, the 1,4-dioxane discharge to groundwater from residential wastewater was estimated at 195 ± 205 kg yr -1, suggesting high risk of contamination to shallow aquifers. The results also demonstrate that installation of NRBs can reduce 1,4-dioxane to levels even lower than the NY State drinking water standard of 1 μg L-1.