Department of Chemical Engineering and Materials, Chemistry Science Faculty, Complutense University of Madrid, 28040 Madrid, Spain.
Department of Forest and Environmental Engineering and Management, E.T.S.I. Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040 Madrid, Spain.
Molecules. 2021 Oct 25;26(21):6425. doi: 10.3390/molecules26216425.
This study focused on the reduction of the treatment cost of mature landfill leachate (LL) by enhancing the coagulation pre-treatment before a UVA-LED photo-Fenton process. A more efficient advanced coagulation pretreatment was designed by combining conventional coagulation (CC) and electro-coagulation (EC). Regardless of the order in which the two coagulations were applied, the combination achieved more than 73% color removal, 80% COD removal, and 27% SUVA removal. However, the coagulation order had a great influence on both final pH and total dissolved iron, which were key parameters for the UVA-LED photo-Fenton post-treatment. CC (pH = 5; 2 g L of FeCl6HO) followed by EC (pH = 5; 10 mA cm) resulted in a pH of 6.4 and 100 mg L of dissolved iron, whereas EC (pH = 4; 10 mA cm) followed by CC (pH = 6; 1 g L FeCl6HO) led to a final pH of 3.4 and 210 mg L dissolved iron. This last combination was therefore considered better for the posterior photo-Fenton treatment. Results at the best cost-efficient [HO]:COD ratio of 1.063 showed a high treatment efficiency, namely the removal of 99% of the color, 89% of the COD, and 60% of the SUVA. Conductivity was reduced by 17%, and biodegradability increased to BOD:COD = 0.40. With this proposed treatment, a final COD of only 453 mg O L was obtained at a treatment cost of EUR 3.42 kg COD.
本研究旨在通过在 UVA-LED 光芬顿工艺前增强混凝预处理来降低成熟垃圾渗滤液（LL）的处理成本。通过将常规混凝（CC）和电混凝（EC）相结合，设计了一种更有效的高级混凝预处理方法。无论两种混凝剂的顺序如何，组合都能达到 73%以上的色度去除率、80%的 COD 去除率和 27%的 SUVA 去除率。然而，混凝顺序对最终 pH 值和总溶解铁有很大影响，这是 UVA-LED 光芬顿后处理的关键参数。CC（pH=5；2 g L 的六水合氯化铁）后接 EC（pH=5；10 mA cm）导致 pH 值为 6.4 和 100 mg L 的溶解铁，而 EC（pH=4；10 mA cm）后接 CC（pH=6；1 g L 的六水合氯化铁）导致最终 pH 值为 3.4 和 210 mg L 的溶解铁。因此，后一种组合更适合后续的光芬顿处理。在最佳成本效益[HO]：COD 比为 1.063 时，结果表明处理效率很高，即去除了 99%的色度、89%的 COD 和 60%的 SUVA。电导率降低了 17%，生物降解性提高到 BOD:COD=0.40。采用该处理方法，在处理成本为 3.42 欧元 kg COD 的情况下，最终 COD 仅为 453 mg O L。
