城市污泥对不同质地土壤保水效果研究

Research of the Effects of Urban Sludge on Water Retention in the Soils with Different Textures

利用城市污泥滞水性强的特性可开发污泥作为保水剂的新功能。通过土培实验,在砂土、壤土和粘土中加入不同质量的污泥,研究污泥对不同质地土壤的保水效果。结果表明:在充分供水条件下,添加污泥能显著提高3种质地土壤的持水能力,土壤中添加20%的污泥后,砂土、粘土和壤土初始含水率分别增加11.2%、8.7%和8.8%;在3种质地土壤中添加污泥均可增大土壤的保水性,使水分蒸发减慢,且污泥添加量越多,土壤含水率越大;土壤累积失水量主要受到土壤中含水量的影响,也和不同质地土壤自身的蒸发量有关;在150 g土壤中添加10 g污泥,对砂土保水性提高不大,对壤土保水性提高最大,随着添加污泥量的增多,污泥对砂土的保水效果提高最明显。研究表明:开发污泥做为保水剂是可行的,这为污泥的资源化利用提供了新的途径,也为复合保水剂的研制提供了新的廉价材料,对于污泥治理及农业节水都有重要意义。

Urban sewage sludge may be exploited as a kind of water-retaining agent due to its characteristics of strong water retention. In this paper, on the basis of pot soil experiments, sludge with different mass was added into sand, loam and clay for study of its effects on water retention in the soils with different textures. The results showed that water retention capacity of the soils was obviously improved by addition of sewage sludge under the precondition of sufficient water supply. After the sludge accounted for 20% of the soil, moisture content of the sand, loam and clay increased by 11.2%, 8.7% and 8.8% respectively, compared to their initial moisture content. Moreover, water evaporation was slowed down. The more the sludge was added, the higher the soil moisture content was. Soil moisture content was the main influencing factor for accumulative soil moisture loss and self-evaporation features of the soils with different textures were also related factors. When 10 g of sludge was added into 150 g of sand, loam and clay respectively, water retention in sand was improved slightly, but that in loam was increased quite much. With the increase of sludge addition, the effect on the water retention in sand was improved most obviously. Therefore, it was concluded that it was feasible to develop sewage sludge as a water-retaining agent, which provided a new pathway for reuse of sewage sludge and a new cheap material for development of water-retaining composite, with great significance for sludge treatment and agricultural water conservation.