ABSTRACT

Combination of ‘green’ coagulation and powdered activated carbon adsorption was tested for removal of benzophenone (BP), benzophenone-3 (BP-3) and caffeine (CF) from treated municipal wastewater at realistic concentration levels (1–2 µg/L). At the same time it was tracked how the process affected effluent organic matter (EfOM) by measuring chemical oxygen demand (COD). Green coagulant was produced from dry common bean seed in laboratory. Combined coagulation-adsorption experiments were performed by applying different dosing sequences of process materials. Removal of hydrophobic BP and BP-3 by separate adsorption (from 79 to 98%) was not significantly hindered by the addition of the coagulant (activated carbon dose of 5 or 20 mg/L). However, in some cases negative effects were observed for hydrophilic caffeine, depending on the carbon dose, dosing sequence and presence of total suspended solids (TSS). Thus, when coagulant was firstly added into water without TSS before low activated carbon dose of 5 mg/L, caffeine removal dropped from 26% to 5%. Conversely, when TSS were present in the water sample, the removal of caffeine was not hindered under the same PAC dose and dosing sequence. The importance of the process optimisation related to removal of organic micropollutans of different hydrophilicity has been shown in this paper. Removal of around 30% of COD regardless of the dosing sequence was achieved.

摘要

测试了“绿色”混凝和粉末活性炭吸附相结合，以从处理过的城市废水中以实际浓度水平 (1–2 µg/L) 去除二苯甲酮 (BP)、二苯甲酮 (BP-3) 和咖啡因 (CF) . 同时，通过测量化学需氧量 (COD) 来跟踪该过程如何影响出水有机物 (EfOM)。绿色凝固剂是在实验室用干燥的普通豆种子制成的。通过应用不同的工艺材料给药顺序进行组合的混凝-吸附实验。通过单独吸附（从 79% 到 98%）去除疏水性 BP 和 BP-3 并没有受到加入混凝剂（活性炭剂量为 5 或 20 mg/L）的显着阻碍。然而，在某些情况下，亲水性咖啡因会产生负面影响，具体取决于碳剂量，给药顺序和总悬浮固体 (TSS) 的存在。因此，当在 5 mg/L 的低活性炭剂量之前首先将混凝剂加入到没有 TSS 的水中时，咖啡因的去除率从 26% 下降到 5%。相反，当水样中存在 TSS 时，在相同的 PAC 剂量和给药顺序下，咖啡因的去除不会受到阻碍。与去除不同亲水性的有机微污染物相关的工艺优化的重要性已在本文中得到体现。无论给药顺序如何，都可去除约 30% 的 COD。在相同的 PAC 剂量和给药顺序下，咖啡因的去除不受阻碍。与去除不同亲水性的有机微污染物相关的工艺优化的重要性已在本文中得到体现。无论给药顺序如何，都可去除约 30% 的 COD。在相同的 PAC 剂量和给药顺序下，咖啡因的去除不受阻碍。与去除不同亲水性的有机微污染物相关的工艺优化的重要性已在本文中得到体现。无论给药顺序如何，都可去除约 30% 的 COD。