城市污泥土地利用研究

STUDY ON UTILIZATION OF MUNICIPAL SEWAGE SLUDGE IN FARMLAND AND FOREST LAND

通过培养试验、盆栽试验和田间试验系统地研究了污泥的组分特征、性质及其农地和城市园林绿化地利用对作物或绿化灌木、土壤肥力及其环境的影响，结果表明，污泥富含有机质和氮磷养分，且养分当季有效性介于化肥农家肥之间。施用污泥将明显提高土壤肥力，表现改善土壤物理性质；增加土壤肥机质和氮磷水平，并增加土壤生物活性，因此施用污泥的处理作物产量较高，并有利于后茬作物的稳健生长。但污泥施用也存在重金属。

The composition of municipal sewage sludge and its effect on plant growth,soil fertility and agroenvironments were studied by filed.greenhouse and incubation experiments.The results showed that sewage sludge contained quite a lot of organic matter and plant nutrients such as nitrogen and phosphrous.Bioavailabilities of N and P of sludge origin were higher than those from ordinary farmyard manures.Sewage sludge significantly improved soil physical,chemical and biological properties by increasing soil waterstable aggreates,soil organic matter,humus,nitrogen and phosphrous contents,also enhancing soil respiration and the number of total microorganisms and lowering soil bulk density at the same time.Consequently,higher yield could be obtained owing to application of sludge.However,sewage sludge also contained pollutants such as heavy metals and pathogen.It was found that sludgeborne metals were easily accumulated in soil and plant,especially in vegetable soil and foliar vegetables.Besides,sludge had a pronounced effect in lowering soil pH which might affect the mobilization of heavy metals in soil.Generally speaking,it was feasible for municipal sewage sludge to apply on soil as fertilizer or soil amendent if the pollutant contents in the sludge and pollutant concentration in soil amended with sewage sludge were under the upper limited value.But sewage sludge should be avoided to apply directly on vegetable soil.It was suggested that developing organoinorganic compound fertilizer with sludge was a practical method to dispose sewage sludge on the farmland.