施用辐照处理的污泥对环境影响的研究

Effects of Utilization of Irradiated Sewage Sludge on Environment

采用田间试验及土柱试验方法,研究了液态污泥辐照后直接施用于菜地对环境的影响,结果表明,土壤有机质、全氮、全磷、速效氮、速效磷的含量皆随着污泥施用量的增加而增加,辐照处理还能增加速效氮的含量。田间持水量随着污泥施用量的增加而增加,而容重、pH值则下降。污泥施用对土壤盐分的增加最明显,田间试验污泥用量为80t·hm-2的土壤电导率比对照增加3倍,盆栽试验则增加24倍。施用污泥使土壤pH降低,土壤重金属的积累量增加,污泥用量为80t·hm-2时,土壤中Cu、Zn、Cd的含量皆超过二级环境质量标准。淋溶模拟试验表明,当污泥用量为80t·hm-2时,淋溶液的NO-3-N、P含量超过Ⅰ、Ⅱ类地面水标准,但用量达120t·hm-2时并未超过Ⅲ类地面水标准。施用辐照处理污泥能加剧上述趋势。

Both field trial and pot experiment were conducted for 3 years to study the effects of irradiated sewage sludge on some soil properties. The results obtained from the field trial showed that contents of soil organic matters, total N, total P, available N and available P increased with the increment of the irradiated sewage sludge added to field, and the contents of available N in swage sludge also increased after irritation. The water holding capacity for the soil increased with the increment of sewage sludge applied, but it was adverse for the bulk density and pH of the soil. The amount of sewage sludge applied had a markedly influence on salt contents of the soil, while the electronic conductivity of the soil with sewage sludge applied at 80t·hm^-2 were three times in field trial and 24 times in pot experiment higher than that for the control treatment （without sewage sludge）. It has also been found that application of sewage sludge could decrease soil pH and increase the concentrations of heavy metals in soil, as the concentrations of Cu, Zn and Cd in soil were discovered to exceed the second category of the environment quality standard. Another eluviated experiment was conducted in PVC tubes for 12 weeks to simulate the effect of swage sludge on the quality of underground water, the results gained indicated that contents of NO3^--N and P in percolate exceeded the first and second categories of surface water quality standard when sewage sludge was applied at 80t·hm^-2, but it did not exceed the third category when the amount of sewage sludge was raised to 120t·hm^-2. Application of irradiated swage sludge could amplify this trend.