共消化污泥施用对贫瘠土壤性质和蔬菜品质的影响

将市政污泥、餐厨垃圾和果蔬垃圾的共消化污泥进行农业利用,通过分析土壤和蔬菜中营养元素和重金属含量,研究共消化污泥对土壤营养元素变化、蔬菜养分吸收、土壤重金属累积、蔬菜重金属积累的影响。结果表明,共消化污泥施用显著提高了土壤有机质、总氮、总磷含量,且提高幅度与共消化污泥的施用量呈线性关系,同时促进了蔬菜对氮、磷的吸收和利用,但土壤总钾含量和蔬菜对钾的吸收受共消化污泥施用影响较小。共消化污泥施用后,土壤中Zn、Cu和Cd含量增加,尤其是Cd含量增加较明显,并且在蔬菜中累积,但土壤重金属含量均低于土壤环境质量标准二级标准规定的限值,蔬菜可食部分中Cu、Zn、Cr和Cd含量均低于食品中污染物限量规定的限值。因此,在共消化污泥农业利用过程中,仍需重点关注重金属含量的变化和累积。

Effects of Co-digested Sludge Application on Infertile Soil and Vegetable Quality

The addition of food,fruit and vegetable waste may promote the efficiency of sewage sludge digestion.Agricultural use of co-di-gested sludge is an effective method for sludge disposal and soil improvement.In this study,the co-digested sludge was applied for agricul-tural use via plot experiments.Two vegetable species（radish and Chinese cabbage）were chosen as test plants.Effects of co-digested sludge application on change of soil nutrient and heavy metal contents,and their uptake and accumulation by vegetables were studied.The results showed that content of organic matters,total nitrogen,and total phosphorus in soil significantly increased due to the co-digested sludge application,and a linear relationship was observed between the soil nutrient increase and co-digested sludge dosage.The nitrogen and phosphorus uptake by vegetables were promoted;while the total potassium content in soil and vegetables was little influenced by co-digested sludge ap-plication.After co-digested sludge application,the content of Zn,Cu and Cd in soil increased,especially Cd was accumulated in soil and vegetable,however,all the soil heavy metal contents were lower than the limits of the secondary standards in Environmental Quality Standard for Soils.The heavy metal contents in edible part of vegetables were lower than the maximum levels of contaminants in foods.However,the variation and accumulation of heavy metals needs to be concerned when the co-digested sludge is applied.