Study On The Wastewater Treatment And Its Agricultural Reuse Of Shihezi City

According to the present conditions of the water resousce and water environment in Shehezi City, Xingjian, the thesis analyzes the feasibility and necessity of the wasterwater reuse in agriculture (including forestry and grassland ) irrigation. In the light of the high water contaminant level and the practical situation that after the wasterwater treatment, the agriculture reuse and the discharge into the reservoir should be considered, the sequencing batch reacater (SBR) technics is used in the wastewater treatment after comparison. The experiment indicates that the SBR technics functions effectively in the treatment of the heavy concentration wastewater. The reduction rate of chemical oxygen demanded (COD) and total phosphate (TP) could up to 90%, and that of total nitrogen (TN) and ammonial nitrogen (NH4-N) could reach 70% under experiment. In addition, the SBR technics can adjust the operation patterns on the basis of the different drainage ways of the wastewater, and so the treated water can meet the grade one of Integrate Wastewater Discharge Standard and the Standards for Irrigation Water Quality. The operational parameter, which is used when the wastewater reused in agriculture irrigation or discharged into reservoir, is also worked out there.The greastest obstacle to the wastewater's reuse in agriculture irrigation is the heavy metal pollution and etc. But till now, there havan't any report about the reduction rate experiment of the activated sludge process used to eliminate the heavy metal. Thus, this experiment also reasearched that the SBR technics functions to eliminate the heavy metal. The research states that the SBR technics can work well in the elimination of these heavy metal, such as mercury (Hg), cdmium (Cd) and lead (Pb), when the inflow concentration meets the standards for municipal wastewater discharge into sewer drainage, after treatment, mercury's and lead's outlet water concentration could reach the agriculture irrigation standards; But cdmium's can't, and it needs to be treated further. And so does the hexavalent chromium (Cr6+) and total chromium (Tr); even if their reduction rate are not so hige, their outlet water concentration still could reach the agriculture irrigation standards.