| At present, the water environmental pollution pressure put forward higher requirements on the treatment efficiency of sewage treatment plant. Sewage treatment plant using conventional activated sludge process, can achieve good treatment effect on BOD5 and COD, but the removal effect of nitrogen and phosphorus is relatively poor. Among them, the nitrogen removal efficiency is 20%-50%, the phosphorus removal efficiency was 20%～30%, the content of total nitrogen and total phosphorus in the water exceeded the critical concentration can cause eutrophication. Therefore, the sewage treatment plant should be implemented on COD, TN, TP and other organic pollutants comprehensive efficient processing. In a process of sewage treatment, energy consumption, sewage treatment pond covers an area of two, sludge disposal problems, restricting the quality and efficiency of sewage treatment plant.Based on the severe water pollution situation at home and abroad and the operation status of wastewater treatment plant, we carried out the following research:First of all, taking a certain area of city sewage as the research object, the treatment effect of the pollutants in wastewater A/O process under low oxygen conditions on. Secondly, using commercially available powder as raw material, the magnetic reagent modification the principle analysis and test research on Preparation and accounting of the magnetic drug production cost. Finally, in the reaction tank and adding magnetic reagent modification, adding modified magnetic agents before and after A/O treatment of various pollutants results, analysis of the modified magnetic medicament effect on sewage treatment efficiency, the effect of magnetic reagent modification on the reduction effect, the reaction pool two sedimentation tank the sludge in the sludge sedimentation performance and inhibit the occurrence of sludge bulking. The main results are as follows:(1) carried out a pilot study on A/O process for treatment of domestic sewage in the low oxygen environment in. After the stage of sludge cultivation, domestication, and completed the preliminary work of the test. During the test, the dissolved oxygen on the reaction tank of low dissolved oxygen area for 24 hours of uninterrupted monitoring, always maintain a low dissolved oxygen reaction pool of dissolved oxygen in the area from 0.5 to 0.8 mg/L. Pilot study on stage in a day on the reactor inlet and outlet sampling, analysis of changes in the sewage COD, NH3-N, TN, TP and other pollutants. The experimental results showed that the content of dissolved oxygen in the reactor of aerobic tank is low, the system of COD, NH3-N, TN and TP average removal rate can reach 68%,55%,51% and 44%. The results showed that under low dissolved oxygen conditions, choose a better process and optimize the process parameters, can achieve better treatment effect on various pollutants.(2) the domestic and foreign related magnetic medicament preparation, modification of the development process with concentrated sulfuric acid, ordinary magnetic powder modified by magnetic agent.Experimental study on physicochemical effect of poly aluminum chloride to remove the pollutants in wastewater using magnetic medicament, modified by. The experimental results show that with the increase of the drug, dosage of two kinds of residual medicament sewage after the COD, TP content decreased. Although the removal effect of COD, TP failed to magnetic reagent with PAC as well, but considering the magnetic reagent modification can be recovered by magnetic drum separator. Therefore, the use of magnetic reagent modification can greatly reduce the use cost of chemicals, reduce sewage treatment investment.Analysis of the effect of magnetic dosage modification on activated sludge microbial populations using denaturing gradient gel electrophoresis. The results show that the change of magnetic drug will affect the microbial abundance, the positive effect on the part of the microorganism, while some microorganisms can restrain.In addition, the magnetic drug production cost was found in the sale of its cost accounting, and PAC flat, has a competitive advantage..(3) remain unchanged test operating conditions, parameters of each reaction tank before the stage, in the reaction tank and adding magnetic chemical modification. The experimental results show that the reaction of COD, NH3-N, TN and TP average removal rate can reach 81%,80%,69% and 70%, compared with the reactor magnetic lmpga was modified before the removal rate increased by 19%,45%,35%,59%. (4) The experimental study on the sludge settling performance shows that the settling property of the sludge is better than that of the modified magnetic medicament. In practical application, good sludge settleability can avoid due to loss of sludge bulking caused by floating mud, sludge reduction, improve the concentration of the sludge in the reactor, greatly improving the activated sludge for each pollutant treatment effect.(4) according to the experimental study on sedimentation performance of activated sludge showed that the addition of magnetic drug after the settlement of the sludge is better than without adding magnetic reagent modified sludge. In practical application, good sludge sedimentation can be avoided because of the sludge expansion brings floating sludge phenomenon, reduce sludge loss, improve the sludge concentration.(5) residual sludge emissions after the chemical reaction of magnetic pool were analyzed. The results show that the magnetic lmpga was modified, compared to magnetic sludge discharge time adding medicament is reduced by 47%, greatly reducing the amount of mud. The analysis results show that the change of magnetic drug can significantly reduce the sludge quantity of residual sludge, reduce sludge disposal costs, greatly reduce the cost of sewage treatment. |
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