农村生活垃圾厌氧/准好氧生物反应器堆肥产物的安全性分析

Safety assessment of composting products derived from rural domestic waste processed through anaerobic/semi-aerobic bioreactors

为实现农村生活垃圾的资源化利用,评价了农村生活垃圾堆肥产品的品质,探讨了该堆肥产品农林利用的可行性,并基于淋滤实验从生态环境保护角度提出了堆肥的施肥策略。研究表明:发酵1.5年的堆肥产品中有机质质量分数为31.28%,总养分为3.84%,重金属由高到低依次为Cu(1322.02 mg/kg)、Pb(118.39 mg/kg)、Cr(91.61 mg/kg)、Cd(8.81 mg/kg),按照15%(质量分数)的比例施用后,土壤质量符合相关要求,但存在轻微生态风险。在淋滤过程中,淋溶液中总氮和硝酸盐氮浓度呈指数下降趋势,氨氮呈先增加再降低的趋势,相较于发酵1年的堆肥产品,发酵1.5年堆肥产品的淋溶液中氨氮浓度显著降低(P<0.01);模拟春季、雨季、旱季施用发酵1.5年的堆肥产品,10000 m^(2)园林绿地中总氮年溶出累积量介于24534~31783 g,约占初始总氮含量的10%;春季施肥氮释放与作物生长同步,更有利于作物生长。

For the resource utilization of domestic waste in the rural areas,the quality of composting and its feasibility of agricultural and forestry utilization were analyzed and discussed.The fertilization strategy of the composting was proposed by the leaching experiment as well.The results indicated that the mass ratio of organic matter and the total nutrient of the composting were 31.28%and 3.84%,respectively.The heavy metals in descending order was Cu(1322.02 mg/kg),Pb(118.39 mg/kg),Cr(91.61 mg/kg)and Cd(8.81 mg/kg).After fertilizing the composting(one and a half years)with mass ratio of 15%,the soil quality met the relevant requirements but presented a slight ecological risk.During the leaching process,the concentration of total nitrogen and nitrate nitrogen in the leaching decreased exponentially,while ammonia nitrogen showed an increasing trend before decreasing,and its concentration leaching from the composting for one and a half years was significantly lower than that for one year(P<0.01).Fertilizing one and a half years compost product in spring,rainy season and dry season,the total amount of total nitrogen dissolved in 10000 m^(2)landscaping land was 24534-31783 g,which accounted for 10%of the initial total nitrogen content.Moreover,fertilizing in spring,the release amount and time of nitrogen were synchronized with the growth of crops,which was beneficial to the crops growth.