污泥修复沙化土壤水分蒸发试验研究

On evaporation of moisture of composite media by sludge remediation of desertified soil

通过"泥-沙"复合介质调控沙土水分蒸发,选取污泥与沙土不同的掺混比(0、10%、15%、20%、30%、50%)为影响因子进行沙箱模拟蒸发试验,测定分析不同掺混处理后沙土的含水率、累积蒸发量、蒸发速率等指标随时间变化的规律,并进行单一/复合土壤保水能力评价。结果表明,随蒸发试验进行,复合土壤含水率的降低幅度随泥沙混比例的增加而减小;在累积蒸发量随时间变化过程中,当掺混比为50%时,累积蒸发量最大;当掺混比为20%时,累积蒸发量最小。泥沙不同掺混处理对沙土水分蒸发速率也具有显著影响,前28 h,蒸发速率最大的为50%掺混比,最小的为20%掺混比;28 h以后,蒸发速率最大为沙土,最小为50%掺混比。在单一/复合土壤保水能力评价中,泥沙掺混比例为20%的复合土壤,Δm、η和k 3个参数值均最小。综上所述,泥沙掺混可有效抑制土壤水分蒸发,且泥沙掺混比为20%的复合土壤保水持水效果最好。

This paper is aimed to provide a reference for improving the water-holding capacity of the desertified soil and laying down a reasonable mixing system of the sediment. To achieve the purpose,we have done the experiment on the application of the"mud-sand"composite medium system to control the sandy soil water evaporation. And,in the given paper,we have also carried out the sandbox simulated evaporation test with the sewage sludge in the sand soil different mixed ratios,e. g. 0,10%,15%,20%,30%,and 50%,as the influential factors. And,later,we have also analyzed and determined the changing regularity of the sandy soil water content with the time prolonging,and with the cumulative evaporation,as well as the evaporation rate, etc. through the different sediment mixing treatments.Thus,consequently,the water retention capacity of the single/composite soil has been examined and registered. The results of our experiments prove that,with the evaporation test being carried on,the water content decreasing range in the composite soil may tend to decrease with the increase of the sediment mixed ratio. In the process while the cumulative evaporation varies with time,it can be found that the cumulative evaporation is the maximum when the mixing ratio is 50%,but the cumulative evaporation is the minimum,when the sediment mixing ratio is 20%. At the same time,different mixing treatments of the sediment can also have different remarkable effects on the sandy soil water evaporation rate. For example,during the first 28 hours,when the sediment mixing ratio is 50%,the evaporation rate can be made maximalized,and,when the mixing ratio is 20%,the evaporation rate can be made minimalized. However,28 hours later,the sandy soil evaporation rate can be made maximalized.However,when the mixing ratio is 50%,the evaporation rate can be made minimalized. In addition,when evaluating the single/composite soil water retention capacity,we have made a comparison of the said single/composite soil water retention capacity with some other mixed ratios,and then found that all the 3 parameters Δm、η 和 R_I are at the minimum level when the rate of the sediment mixture is lying at 20%. Therefore,it can be concluded that,sediment mixing can effectively inhibit the soil water evaporation,whereas the composite soil has the best water conserving and holding effect when the proportion of the sediment mixture is kept at a mere 20%.