Study On The Compound Of Saline-Alkali Soil And Sludge Based On Planting Soil

At present,with the rapid development of sewage treatment business,sludge production is also increasing year by year.By the end of 2014,3717 sewage treatment plants have been completed in the country,with sewage treatment capacity of about 157 million cubic meters/day,the cumulative treatment of sewage is 48.06 billion cubic meters,and the operating load rate is 84.1%.However,according to the national urban sewage treatment facilities at the end of 2013 construction and operation of the notification,by the end of 2013,the national sludge treatment and disposal facilities construction scale have only been completed by 43.3%.Sludge has high water content,complex compositions,containing N,P,K and other nutrients,and sludge compost on the one hand can stabilize the organic matter in the sludge,kill pathogens,reduce harmful gases;on the other hand because of its small density,it can increase the soil porosity,reduce soil bulk density,making the sludge after composting can be effectively applied to the land landscaping which.In addition,the increasing problem of desertification in our country has seriously hindered the development of our country's production.Therefore,this paper makes full use of the adhesion of organic matter in the sludge,and cooperates with the sandy soil to increase the water retention and fertilizer fertility of the soil.In this paper,the experimental materials are sandy soil and composting sludge from Zhangguizhuang sewage treatment plant.The weight ratio of sludge/sand soil were 0:10,1:9,2:8,3:7,4:6,5:5,6:4,7:3,8:2,9:1,10:0,that is,the dry weight of sludge is 0,10%,20%,30%,40%,50%,60%,70%,80%,90%,100%.Through the comparative study on the physical and chemical properties of soils,it was found that the optimum ratio of sludge/sand soil was 1:9,that is,the dry weight of sludge was10%.After determining the optimal ratio of sludge/sandy soil,this paper continued to explore the method of rapid formation of soil aggregates.Using dry/wet cycle +pressurized stirring method,the number of dry and wet cycles in the experiment was3,6,9 times,and finally determine the best mixing program: dry and wet cycle 3times,in the mechanical mixer to 250 r/min pressure stirring.In addition,in order to further study the compound soil,the alfalfa and cockscomb were studied in this paper.The root length,stem length and chlorophyll content of alfalfa and cockscomb werecompared.Finally,after a series of indicators of detection and planting experiments,this paper identified the best mix of sludge/sandy soils in the compound soil: the dry weight of sludge in the soil is 10%,the compound soil will be carried out 3 times the wet and dry cycle,and in the mechanical mixer to 250 r / min pressure stirring.