Unit loading of sewage sludge

The indicator describes the quantities of sludge used annually in agriculture. The agricultural use of sludge provides organic substance and nutrients. However, sludge can also contain heavy metals that can accumulate in the soil.本指标用于描述农业领域年度污泥使用总量。污泥的农业应用可为土壤提供有机质与营养元素，但污泥中亦可能含有重金属，此类物质会在土壤中累积。