San Jose Creek Water Quality Control Laboratory, Sanitation Districts of Los Angeles County, 1965 South Workman Mill Road, Whittier, CA 90601, USA.
San Jose Creek Water Quality Control Laboratory, Sanitation Districts of Los Angeles County, 1965 South Workman Mill Road, Whittier, CA 90601, USA.
Water Res. 2016 Mar 15;91:174-82. doi: 10.1016/j.watres.2016.01.002. Epub 2016 Jan 7.
Municipal wastewater treatment plants (WWTPs) are frequently suspected as significant point sources or conduits of microplastics to the environment. To directly investigate these suspicions, effluent discharges from seven tertiary plants and one secondary plant in Southern California were studied. The study also looked at influent loads, particle size/type, conveyance, and removal at these wastewater treatment facilities. Over 0.189 million liters of effluent at each of the seven tertiary plants were filtered using an assembled stack of sieves with mesh sizes between 400 and 45 μm. Additionally, the surface of 28.4 million liters of final effluent at three tertiary plants was skimmed using a 125 μm filtering assembly. The results suggest that tertiary effluent is not a significant source of microplastics and that these plastic pollutants are effectively removed during the skimming and settling treatment processes. However, at a downstream secondary plant, an average of one micro-particle in every 1.14 thousand liters of final effluent was counted. The majority of microplastics identified in this study had a profile (color, shape, and size) similar to the blue polyethylene particles present in toothpaste formulations. Existing treatment processes were determined to be very effective for removal of microplastic contaminants entering typical municipal WWTPs.
城市污水处理厂（WWTP）常被怀疑是向环境中排放微塑料的重要点源或渠道。为了直接调查这些怀疑，研究了南加州的 7 个三级处理厂和 1 个二级处理厂的污水排放情况。该研究还研究了这些污水处理设施的进水负荷、粒径/类型、输送和去除情况。在这 7 个三级处理厂中的每一个处理厂，都使用一个组装的筛子堆栈对超过 0.189 百万升的污水进行过滤，筛子的网眼尺寸在 400 和 45μm 之间。此外，在三个三级处理厂中，对 2840 万升的最终污水进行了表面撇渣，使用的是 125μm 的过滤组件。结果表明，三级处理厂不是微塑料的重要来源，这些塑料污染物在撇渣和沉淀处理过程中被有效去除。然而，在下游的二级处理厂，每 1140 升最终污水中平均有一个微粒子被计数。本研究中鉴定出的大多数微塑料的特征（颜色、形状和大小）与牙膏配方中存在的蓝色聚乙烯颗粒相似。现有的处理工艺被确定对去除进入典型城市 WWTP 的微塑料污染物非常有效。
