School of Environment, Tsinghua University, Beijing 10084, China.
School of Environment, Tsinghua University, Beijing 10084, China.
J Environ Manage. 2019 Feb 15;232:895-901. doi: 10.1016/j.jenvman.2018.11.129. Epub 2018 Dec 7.
Food waste (FW) is environmentally unfriendly and decays easily under ambient conditions. Vanadium (V) and chromium (Cr) contamination in soils has become an increasing concern due to risks to human health and environmental conservation. Volatile fatty acids (VFAs) derived from FW was applied as soil washing agent to treat V and Cr-contaminated soil collected from a former V smelter site in this work. The Community Bureau of Reference (BCR) three-step sequential extraction procedure was used to identify geochemical fractions of V and Cr influencing their mobility and biological toxicity. Optimal parameters of a single washing procedure were determined to be a 4 h contact time, liquid-solid ratio of 10:1, VFAs concentration of 30 g/L, and reaction temperature of 25 °C, considering for typical soil remediation projects and complete anaerobic fermentation of FW. Under the optimal conditions, butyric acid fermentation VFAs attained removal rates of 57.09 and 23.55% for extractable fractions of V and Cr, respectively. Simultaneously, a multi-washing process under a constant liquid-solid ratio using fresh and recycled VFAs was conducted, which led to an improvement on the total removal efficiency of toxic metals. The washing procedure could reach the pollution thresholds for several plants, such as of S. viridis, K. scoparia, M. sativa, and E. indica. This strategy enhances the utilization of VFAs derived from food waste, has a positive effect on V and Cr-contaminated soil remediation, wastewater control of soil washing and FW disposal.
食物垃圾（FW）对环境不友好，在环境条件下容易腐烂。由于对人类健康和环境保护的风险，土壤中的钒（V）和铬（Cr）污染已成为一个日益关注的问题。本工作中，将 FW 衍生的挥发性脂肪酸（VFAs）用作土壤洗脱剂，处理从前钒冶炼厂场地采集的 V 和 Cr 污染土壤。采用欧洲共同体理事会（BCR）三步连续提取程序来确定影响 V 和 Cr 迁移性和生物毒性的地球化学形态。考虑到典型的土壤修复项目和 FW 的完全厌氧发酵，确定了单一洗脱过程的最佳参数为 4 小时接触时间、液固比为 10:1、VFAs 浓度为 30g/L 和反应温度为 25°C。在最佳条件下，丁酸发酵 VFAs 对 V 和 Cr 的可提取形态的去除率分别达到 57.09%和 23.55%。同时，在恒定液固比下使用新鲜和回收 VFAs 进行多次洗脱，提高了有毒金属的总去除效率。该洗脱程序可以达到几种植物的污染阈值，如 S. viridis、K. scoparia、M. sativa 和 E. indica。该策略提高了源自食物垃圾的 VFAs 的利用率，对 V 和 Cr 污染土壤修复、土壤洗脱废水控制和 FW 处置具有积极影响。
