Study On Sewage Treatment And Reuse In Greensward By Underground Land Application

Sewage reuse plays an important role in relieving water resources shortage in China. Based on referring to literature, the characteristic of the sewage was analyzed, getting along with the technique development of the wastewater separating treatment and resource utilizing, linking to the characteristic of the need of greenbelt nutrient, the system of the wastewater separating treatment and utilizing----greensward by underground land application system was designed. Experiment was conducted in Lv Qiao Ecological Garden of Bei Shicao village, Changzhi city, Shanxi province. The content of nitrogen(N), phosphorus(P) and potassium(K) in topsoil and the changing parameter of the bacteria and Escherichia Coli on leaves surface and in top soil was studied by greensward by underground land application system and in top water by sprinkler irrigation system. It was discussed to System performance, and its effect on the surrounding environment of the greensward by underground land application. Some conclusions were as follows:1. Because of using underground complement irrigation sewage with the greensward by underground land application, topsoil and leaves surface were in drying status, and in some degree, microorganism survival circumstance was destroyed. Thus, the content of the bacteria and Escherichia Coli on leaves surface and in top soil was markly reduction. The content of Escherichia Coli using underground complement irrigation usage means with greensward by underground land application system was lower 3.77% than that of tap water by sprinkler irrigation system during the experiment at topsoil (0-30cm). There was no significant difference in total bacteria between using usage by the greensward by underground land application system and tap water by sprinkler irrigation system.2. The content of inorganic nitrogen,available phosphorus,available potassium and organic matter was higher using sewage with the greensward by underground land application system than that using tap water by sprinkler irrigation system. And the inorganic nitrogen, available phosphorus, organic matter is absorbed more at the soil layer of 20 ~ 30 cm for the root.3. After using the system of the supplying virescence nutrient, the amount of the biomass per unit area is raised by 60% and the water is saved 0.44 m~3/m~2 per year and also can save 1.184 yuan per m~2 compared to the system of tap water irrigation.4. After the completion of the test facility, Greensward by underground land application without any odor compared to the system of tap water irrigation. In the whole test, It can be adjusted the irrigation during time, conversion of the manual control and auto control. In addition, wastewater can't be overflowed, and it decreased the possible secondary pollution to its surroundings. Sewages disposed by greensward by underground land application system can be used for irrigation purpose of greensward plant. And through the absorption of nutrient compounded of N, P, K by root systems of the greensward plant, polluted water is decontaminated and utilized locally where it is produced. By the application of this method, not only the difficulties of transportation and high expenditure of thorough purification of sewages is avoided, but also a new and valid method for fertilization and irrigation for greensward plant come into appearance, which subtracted the application of fertilizer and water for greensward plant. According to the analysis and investigation conclusion, the greensward by underground land application system effectively controlled the possible secondary pollution to surroundings.The system breaks the traditional mode of the wastewater treatment and reusing, provides a new way for wastewater reusing as resource.