Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
Water Res. 2019 Mar 15;151:310-317. doi: 10.1016/j.watres.2018.11.089. Epub 2018 Dec 27.
Applications of Fenton's oxidation of landfill leachate is limited by both high reagent requirements and a large amount of sludge generation. To address those issues, forward osmosis (FO) and humic acid (HA) recovery were incorporated with Fenton's treatment. In the FO, leachate was concentrated by 3.2 times in 10 hours using a 5-M NaCl draw solution. The HA recovery increased from 1.86 to 2.45 g L at pH 2 after FO concentration, mainly because of the replacement of O in the HA structure by other inorganics (i.e., Cl, Na, K) with higher molecular weights. Due to the movement of alkalinity causing species (i.e., HCO, CO) to the draw side driven by a concentration gradient, the HSO requirement per g of recovered HA and per g of removed COD decreased by 46.4% and 17.1%, respectively. The HA recovery also decreased sludge generation by 30%. At a dimensionless oxidant dose of 0.5, the proposed system reduced the overall requirement of HSO by 25.2%, NaOH by 34.6%, and both FeSO.7HO and HO by 35%, compared to the standalone Fenton's treatment of raw leachate. Those results have demonstrated that the proposed system could greatly decrease the leachate volume, lower the reagent requirements, and reduce the sludge production towards sustainable leachate treatment.
芬顿氧化法处理垃圾渗滤液的应用受到高试剂需求和大量污泥产生的限制。为了解决这些问题，正向渗透（FO）和腐殖酸（HA）回收与芬顿处理相结合。在 FO 中，渗滤液在 10 小时内使用 5-M NaCl 汲取液浓缩了 3.2 倍。FO 浓缩后，HA 回收率从 2 pH 时的 1.86 增加到 2.45 g/L，主要是因为 HA 结构中的 O 被其他分子量更高的无机物（即 Cl、Na、K）取代。由于碱度迁移物种（HCO、CO）在浓度梯度的驱动下向汲取侧移动，每回收 1 g HA 和每去除 1 g COD 所需的 HSO 分别减少了 46.4%和 17.1%。HA 回收还减少了 30%的污泥生成。在无量纲氧化剂剂量为 0.5 的情况下，与单独的原始渗滤液芬顿处理相比，该系统使 HSO 的总需求量减少了 25.2%，NaOH 的需求量减少了 34.6%，FeSO·7HO 和 HO 的需求量均减少了 35%。这些结果表明，该系统可以大大减少渗滤液的体积，降低试剂的需求，并减少污泥的产生，实现可持续的渗滤液处理。
