Li Xiang, Wang Shengwei, Zhao Silan, Chang Huiming, Li Yanxia, Zhao Yan
School of Environment, Beijing Normal University, Beijing 100875, China.
School of Environment, Beijing Normal University, Beijing 100875, China.
Sci Total Environ. 2023 Nov 25;901:165909. doi: 10.1016/j.scitotenv.2023.165909. Epub 2023 Jul 29.
Composting is one of main technologies for treating and thus utilizing livestock manure and sludge. However, heavy metals are major concerns in compost utilization due to their potential environmental hazards and health risks. This study aimed to investigate the effects of electric field-assisted composting on the variations of heavy metals and the affecting factors. The results showed that electric field significantly reduced the contents of bioavailable heavy metals including Mn, Zn, Cu, Ni, and Cd, with their bioavailable concentrations decreasing by 61.7, 63.8, 64.9, 83.7, and 63.8 %, respectively. The heavy metals being transformed into stable states were increased, indicating that the electric field also passivated these heavy metals and reduced their biological toxicity and stabilized their forms. Spearman's correlation analysis revealed that the changes in substances, temperature, and organic matter were the dominant environmental factors affecting the forms of heavy metals. Microbial community analysis indicated an increase in the abundance of metal-resistant bacteria such as Pseudomonas and Bacillus during electric field-assisted composting, with their relative abundances being increased to 2.66 % and 15.63 % in the pile of electric field-assisted composting, respectively, compared to the values of 1.88 % and 4.36 % respectively in the conventional composting. The current study suggests that electric field-assisted composting can significantly reduce the availability of heavy metals in the compost, and thus mitigate the health risks associated with its application.
堆肥是处理并因此利用畜禽粪便和污泥的主要技术之一。然而，由于重金属潜在的环境危害和健康风险，其在堆肥利用中备受关注。本研究旨在探究电场辅助堆肥对重金属变化及其影响因素的作用。结果表明，电场显著降低了包括锰、锌、铜、镍和镉在内的生物可利用重金属含量，其生物可利用浓度分别降低了61.7%、63.8%、64.9%、83.7%和63.8%。转化为稳定态的重金属增加，表明电场还钝化了这些重金属，降低了它们的生物毒性并稳定了其形态。斯皮尔曼相关性分析表明，物质、温度和有机质的变化是影响重金属形态的主要环境因素。微生物群落分析表明，在电场辅助堆肥过程中，假单胞菌和芽孢杆菌等耐金属细菌的丰度增加，与传统堆肥中分别为1.88%和4.36%的值相比，在电场辅助堆肥堆中它们的相对丰度分别增加到2.66%和15.63%。当前研究表明，电场辅助堆肥可显著降低堆肥中重金属的有效性，从而降低其应用带来的健康风险。
