Huntsman Brent E, Staples Charles A, Naylor Carter G, Williams Jim-Bob
Terran Corporation, Dayton, OH 45430-1061, USA.
Water Environ Res. 2006 Nov;78(12):2397-404. doi: 10.2175/106143005x72966.
The fate of nine-mole nonylphenol ethoxylate (NPE9) discharged to an on-site wastewater disposal (septic) system was the focus of a 2-year investigation. Known amounts of NPE9-based detergent were metered daily into the plumbing at a single-family household. The ethoxylate-containing wastewater was discharged to the highly anoxic environment of a 4500-L septic tank before distribution to the oxic subsurface via 100 m of leach line. After 180 days of injecting detergent to the septic system, periodic soil pore water and/or groundwater samples were collected and analyzed for nonylphenol ethoxylates (NPEs), nonylphenol ether carboxylates, and nonylphenol. The NPE9 and degradation intermediates that were measured were reduced by 99.99% on a molar basis. An 18% reduction in molar concentration within the septic tank was observed. This was followed by a further 96.7% reduction of molar concentration within the leach lines. As the pore water migrated through the vadose zone, an additional 99.69% reduction in molar concentration was measured between the bottom of the leach lines (leach line effluent) and the lowest vadose zone monitoring location. The results obtained from these analyses indicate that degradation of the surfactant occurs within the anoxic portion of the disposal system with continued rapid biodegradation in the oxic unsaturated zone. Only trace amounts of degradation residuals were detected in soil pore water. The concentration and distribution of various degradation intermediates with respect to location, time, and ambient physical conditions were evaluated. Rapid and systematic degradation of NPE in on-site wastewater disposal systems was documented.
向现场废水处理（化粪池）系统排放的九摩尔壬基酚乙氧基化物（NPE9）的归宿是一项为期两年调查的重点。已知量的基于NPE9的洗涤剂每天被计量加入到一个单户家庭的管道中。含乙氧基化物的废水在通过100米渗滤管线分配到有氧的地下之前，被排放到一个4500升化粪池的高度缺氧环境中。在向化粪池系统注入洗涤剂180天后，定期采集土壤孔隙水和/或地下水样本，并分析其中的壬基酚乙氧基化物（NPEs）、壬基酚醚羧酸盐和壬基酚。所测量的NPE9及其降解中间体在摩尔基础上减少了99.99%。在化粪池内观察到摩尔浓度降低了18%。随后在渗滤管线内摩尔浓度又进一步降低了96.7%。当孔隙水通过包气带迁移时，在渗滤管线底部（渗滤管线流出物）和最低包气带监测位置之间测量到摩尔浓度又额外降低了99.69%。这些分析得到的结果表明，表面活性剂在处理系统的缺氧部分发生降解，在有氧的不饱和带持续快速生物降解。在土壤孔隙水中仅检测到痕量的降解残余物。评估了各种降解中间体相对于位置、时间和环境物理条件的浓度和分布。记录了现场废水处理系统中NPE的快速和系统降解情况。
