School of Civil Engineering, Hefei University of Technology, Hefei 230009, China.
CSIRO Land and Water, Private Bag No. 5, Wembley, Western Australia 6913, Australia.
Environ Sci Technol. 2021 Jan 5;55(1):393-401. doi: 10.1021/acs.est.0c06781. Epub 2020 Dec 10.
Roxarsone (ROX) is widely used in animal farms, thereby producing organoarsenic-bearing manure/wastewater. ROX cannot be completely degraded and nor can its arsenical metabolites be effectively immobilized during anaerobic digestion, potentially causing arsenic contamination upon discharge to the environment. Herein, we designed and tested a sulfate-mediated bioelectrochemical system (BES) to enhance ROX degradation and immobilization of the released inorganic arsenic. Using our BES (0.5 V voltage and 350 μM sulfate), ROX and its metabolite, 4-hydroxy-3-amino-phenylarsonic acid (HAPA), were completely degraded within 13-22 days. In contrast, the degradation efficiency of ROX and HAPA was <85% during 32-day anaerobic digestion. In a sulfate-mediated BES, 75.0-83.2% of the total arsenic was immobilized in the sludge, significantly more compared to the anaerobic digestion (34.1-57.3%). Our results demonstrate that the combination of sulfate amendment and voltage application exerted a synergetic effect on enhancing HAPA degradation and sulfide-driven arsenic precipitation. This finding was further verified using real swine wastewater. A double-cell BES experiment indicated that As(V) and sulfate were transported from the anode to the cathode chamber and coprecipitated as crystalline alacranite in the cathode chamber. These findings suggest that the sulfate-mediated BES is a promising technique for enhanced arsenic decontamination of organoarsenic-bearing manure/wastewater.
罗氧酸（ROX）广泛应用于动物养殖场，从而产生含有机砷的粪便/废水。ROX 不能被完全降解，其砷代谢物也不能在厌氧消化过程中被有效固定，因此在排放到环境中时可能会造成砷污染。在此，我们设计并测试了一种硫酸盐介导的生物电化学系统（BES），以增强 ROX 的降解和释放的无机砷的固定。在我们的 BES（0.5 V 电压和 350 μM 硫酸盐）中，ROX 和其代谢物 4-羟基-3-氨基苯胂酸（HAPA）在 13-22 天内被完全降解。相比之下，ROX 和 HAPA 的厌氧消化降解效率<85%。在硫酸盐介导的 BES 中，75.0-83.2%的总砷被固定在污泥中，与厌氧消化相比显著增加（34.1-57.3%）。我们的结果表明，硫酸盐的添加和电压的施加相结合对增强 HAPA 的降解和硫化物驱动的砷沉淀具有协同作用。这一发现进一步通过实际的猪废水得到了验证。双室 BES 实验表明，As(V)和硫酸盐从阳极室转移到阴极室，并在阴极室中以结晶砷铝矿的形式共沉淀。这些发现表明，硫酸盐介导的 BES 是一种增强含有机砷粪便/废水砷脱除的有前途的技术。
