To remove organic contaminants from wastewater using cost-efficient and currently existing methods, our study investigated char-fortified filter beds for on-site sewage treatment facilities (OSSFs) in a long-term field setting. OSSFs are commonly used in rural and semi-urban areas worldwide to treat wastewater when municipal wastewater treatment is not economically feasible. First, we screened for organic contaminants with gas chromatography and liquid chromatography mass spectrometry-based targeted and untargeted analysis and then we developed quantitative structure-property relationship models to search for key molecular features responsible for the removal of organic contaminants. We identified 74 compounds (24 confirmed by reference standards) including plasticizers, UV stabilizers, fragrances, pesticides, surfactant and polymer impurities, pharmaceuticals and their metabolites, and many biogenic compounds. Sand filters that are used as a secondary step after the septic tank in OSSFs could remove hydrophobic contaminants. The addition of biochar significantly increased the removal of these and a few hydrophilic compounds (Wilcoxon signed-rank test, α = 0.05). Besides hydrophobicity-driven sorption, biodegradation was suggested to be the most important removal pathway in this long-term field application. However, further improvements are necessary to remove very hydrophilic contaminants as they were not removed with sand and biochar-fortified sand.

中文翻译：

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炭强化滤床从现场污水处理设施废水中去除有机污染物的综合评估。

为了使用经济高效的方法和现有方法从废水中去除有机污染物，我们的研究在长期的现场环境中研究了用于现场污水处理设施（OSSF）的炭强化滤床。当市政废水处理在经济上不可行时，OSSF通常在世界范围的农村和半城市地区用于处理废水。首先，我们通过基于气相色谱和液相色谱质谱的目标和非目标分析来筛选有机污染物，然后我们开发了定量的结构-性质关系模型，以寻找负责去除有机污染物的关键分子特征。我们确定了74种化合物（参考标准已确认的24种化合物），包括增塑剂，紫外线稳定剂，香料，农药，表面活性剂和聚合物杂质，药物及其代谢物，以及许多生物化合物。在OSSF化粪池中用作第二步骤的砂滤器可以去除疏水性污染物。生物炭的加入显着增加了对这些和一些亲水性化合物的去除（Wilcoxon符号秩检验，α= 0.05）。除了疏水性驱动的吸附以外，在长期的现场应用中，生物降解被认为是最重要的去除途径。但是，要去除亲水性很强的污染物，还需要进一步的改进，因为它们不能用沙子和生物炭强化的沙子去除。添加生物炭显着提高了对这些亲水性化合物和一些亲水性化合物的去除（Wilcoxon符号秩检验，α= 0.05）。除了疏水性驱动的吸附以外，在长期的现场应用中，生物降解被认为是最重要的去除途径。但是，要去除亲水性很强的污染物，还需要进一步的改进，因为它们不能用沙子和生物炭强化的沙子去除。添加生物炭显着提高了对这些亲水性化合物和一些亲水性化合物的去除（Wilcoxon符号秩检验，α= 0.05）。除了疏水性驱动的吸附以外，在长期的现场应用中，生物降解被认为是最重要的去除途径。但是，要去除亲水性很强的污染物，还需要进一步的改进，因为它们不能用沙子和生物炭强化的沙子去除。