Experimental Study On Transportation Characteristics And Influencing Factors Of Pollutants With Waste Water Infiltration In Soil And Groundwater

Based on consulting a great deal of literature from the domestic and foreign and adopted technique way of indoor experiment and theoretical analyses, the paper mainly studies the transport rule of water and pollutants in soil and groundwater under waste water infiltration in various conditions. The main results are as follows:(1) The rise characteristic of capillary water in homogeneous soil under groundwater depth was researched. Capillary water upward process can be divided into two stages of rising and steady infiltration according to capillary upward rate, capillary upward average rate of rise is positively related to groundwater depth in stages of rising, and negatively correlated with groundwater depth in stable stages.(2) The transport rule of water, nitrogen, chloride and sulfate in soil and groundwater under waste water infiltration in different groundwater was researched. Different groundwater depth led to the difference in soil moisture distribution and the migration path of sewage irrigation pollutants. Infiltration capacity increased with the in increased groundwater depth. Infiltration rate decreased with the increased groundwater depth at the time that the infiltration was over. The chloride had a similar distribution rules with the SO42- in the soil and groundwater. Their leaching and washing decreased with the increased groundwater depth after infiltration, The longer the migration path and the more the soil moisture content, the deeper the groundwater depth, chloride are easier to stagnate in soil, by contrast, accrual of chloride in groundwater decreased. Leaching and washing of chloride in soil and accrual in groundwater is greater than SO42-. Although the higher of soil moisture potential energy and denitrification were restricted to tendency of NO3--N in sewage from up to down, but the higher of soil moisture potential energy and shorter migration path stimulate NO3--N of soil matrix from subsoil to groundwater, the pollution risk of groundwater increased with the groundwater depth.(3) The transport rule of water, nitrogen, chloride and sulfate in soil and groundwater under waste water infiltration in different soil texture was researched. Initial soil moisture content with the increased soil texture. Infiltration capacity of soil with the decreased soil texture. The cumulant of chloride and SO42- in soil increased with an increase of soil texture, and their increment decreased. Leaching and washing of chloride in soil and accrual in groundwater is greater than SO42-. The pollution level of groundwater caused by chloride is greater than SO42-.NO3--N transport distance in soil and NO3--N content increased amplitude in groundwater also decreased with the increased soil texture.(4) The transport rule of water, nitrogen and chloride in soil and groundwater under waste water infiltration in different soil particle size of sand layer was researched. Because of sand layer has an obvious inhibitive effect on the height of capillary ascension, anastaticwater not penetrate sand layer. Prevent water action was enhanced with increasing soil particle size of sand layer. The cumulant of chloride and NO3--N in soil is greater than homogeneous soil, by contrast, accrual of chloride and NO3--N in groundwater is less than homogeneous soil. Supply amount of chloride and NO3--N from above layer and sand layer increases as particle size of sand rises, and their increment in groundwater also increases as particle size of sand rises.(5) The transport rule of water, nitrogen and chloride in soil and groundwater under waste water infiltration in different sand layer depth was researched. The smaller the sand layer depth, the inbibitional effect of capillary upward water height more obvious. The process of infiltration With the same irrigation reuirement need time as follow:sand layer depth lie on 80cm> homogeneous soil> sand layer depth lie on 10cm> sand layer depth lie on 45cm. The inbibitional effect of chloride by different layer depth in varying degrees, water distribution is continuous in sand layer depth lie on 10cm and 80cm after infiltration, the chloride ion in the groundwater is more than the latter because of inbibitional effect is less than the latter. Chloride ion increment in groundwater is least in sand layer depth lie on 45cm because soil water distribution is noncontinuous. The sand layer the principles of NO3--N transformation and transport in soil can be influenced by the changes of sand layer depth, the changes of NO3--N in groundwater is similar to chloride ion.