Water Quality and Treatment Laboratory, Urban Water Unit, Hydraulics and Environment Department, LNEC - National Civil Engineering Laboratory, 1700-066 Lisbon, Portugal.
Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
Sci Total Environ. 2020 Nov 15;743:140791. doi: 10.1016/j.scitotenv.2020.140791. Epub 2020 Jul 7.
This paper assesses the applicability of a new carob waste-derived powdered activated carbon (PAC) obtained by steam activation for pharmaceutical compounds (PhCs) removal in urban wastewater treatment plants (WWTPs) with activated sludge (AS) secondary treatment. The new carob-derived PAC presents chemical and textural properties similar to a high-performing commercial PAC produced from vegetable source by physical activation. The adsorption isotherms of three target PhCs, carbamazepine, diclofenac and sulfamethoxazole, spiked (at around 100 μg/L) in mixed liquor (ML) and in clarified-ML from the AS-bioreactor of a WWTP show: (i) minor reduction of PAC capacity with real MLs compared to clarified MLs; (ii) the higher the PhC hydrophobicity, the higher the PAC adsorption capacity in both water matrices; (iii) hydrophobic interactions probably overweight electrostatic interactions between the PhCs and the slightly positively charged PAC in these real water matrices with background organics and inorganics. The PhC adsorption results with ML and clarified-ML are used to calibrate the IAST-based tracer model (TRM) and predict the new PAC performance when added to AS-bioreactor vs. in post-secondary treatment, at the PhC naturally-occurring trace concentrations. The modelling projections show (i) one needs higher PAC doses than those reported in the literature, particularly in post-treatment, and (ii) the benefits of PAC dosing to the bioreactor, with only a slightly higher PAC dose being needed when compared to its post-secondary dosing and minimising the capital investment.
本文评估了一种由蒸汽活化获得的新型角豆粉衍生的粉末状活性炭（PAC）在具有活性污泥（AS）二级处理的城市污水处理厂（WWTP）中去除药物化合物（PhCs）的适用性。新型角豆衍生的 PAC 具有与由植物源通过物理活化产生的高性能商业 PAC 相似的化学和结构特性。三种目标 PhCs（卡马西平、双氯芬酸和磺胺甲恶唑）的吸附等温线，在 WWTP 的 AS 生物反应器中的混合液（ML）和澄清 ML 中（约 100μg/L）被添加，结果表明：（i）与澄清 ML 相比，真实 ML 中 PAC 的容量略有降低；（ii）PhC 的疏水性越高，在两种水基质中 PAC 的吸附容量越高；（iii）在这些具有背景有机物和无机物的实际水基质中，PhC 和带少许正电荷的 PAC 之间的疏水相互作用可能超过静电相互作用。使用 ML 和澄清 ML 的 PhC 吸附结果来校准基于 IAST 的示踪剂模型（TRM），并预测在自然痕量浓度下将新 PAC 添加到 AS 生物反应器与后二级处理时的 PAC 性能。建模预测表明：（i）需要比文献中报道的更高的 PAC 剂量，特别是在后处理中；（ii）在生物反应器中投加 PAC 的好处，与后二级投加相比，只需略高的 PAC 剂量，并且最大限度地减少了资本投资。
