铁锰固废促进污泥堆肥进程及其腐殖化特性

Effect of Iron-Manganese Industrial Wastes on Composting Process of Wastewater Sludge and Analysis for Humification Characteristics

利用铁锰类工业固废提升污泥堆肥腐殖化程度,可实现污泥与工业固废的协同处理与资源化利用。文章以污水厂脱水污泥为对象,添加铁锰冶炼渣或铁锰尾矿开展15 d堆肥试验,探究了污泥堆肥的腐殖化进程及特性。将铁锰固废添加至污泥类有机质固体废物中,堆体升温速率更快,50℃以上高温期可达96 h;堆肥处理15 d后,HA/FA均不低于1.0,种子发芽指数GI达到100%以上。堆肥产物除As外,其他重金属含量均低于《农用污泥污染物控制标准》(GB 4284-2018)A级标准限值,堆肥产物适于园地、牧草地、不种植食用农作物耕地使用。添加铁锰冶炼渣的堆肥产物多酚氧化酶、脱氢酶活性最高分别达到2.2μmol/(h·g)、13.5 mg/(d·g),水溶性有机碳含量明显上升,铁锰冶炼渣有利于有机质中间组分向胡敏酸类大分子物质转化,在保留碳素、氮素的同时,提高堆肥稳定性和腐熟度。

Iron-manganese industrial wastes are used to improve the humification degree of sludge composting and realize the synergetic treatment and resource utilization.After iron-manganese smelting residuals or iron-manganese tailings were added to sludge compost mixture,the process and characteristics of sludge humification were studied by composting exper⁃iments for 15 days.Adding iron-manganese slags increased the heating rate of the sludge pile,and the period of thermo⁃philic composting(≥50℃)reached 96 h.After 15 days,the ratio of HA/FA was not less than 1.0,and the seed germina⁃tion index GI were more than 100%.Except for As,the contents of other metals such as Cr and Ni were lower than the limits of the Grade A stipulated by the Agricultural Sludge Pollutant Control Standard(GB 4284-2018),and then the obtained compost products were suitable for garden,pasture,and cultivated land where crops are not planted.The highest activities of polyphenol oxidase and dehydrogenase in the compost products with the addition of iron-manganese smelting slags were 2.2μmol/(h·g)and 13.5 mg/(d·g),respectively,and water-soluble organic carbon increased significantly.Iron-manganese smelting slags was more conducive to the conversion of soluble organic carbon into macromolecular sub⁃stances such as humic acid,and it improved compost stability and maturity while retaining carbon and nitrogen.