The Research On Dealing With Wastewater That Include Nitrogen And Phosphorus By Light Calcined Powder

The phenomena of water shortage and serious water pollution are existed in our country, and the phenomenon of eutrophication is due to the contents of nitrogen and phosphorus seriously overweight the state standard. Therefore, controlling the nitrogen and phosphorus pollution has become the current problems to be solved. The traditional method of nitrogen and phosphorus removal is effect, but it is likely to cause the secondary pollution. Magnesium ammonium phosphate precipitation method can not only remove the nitrogen and phosphorus in the sewage, but also the nitrogen and phosphorus to be recycled. So, this method can achieve the purpose of "turning waste into treasure". Up to now, the main factors that limit the method to be promoted is the magnesium of high consumption and cost in the process, which is lead to increase the treatment costs. Light buring powder, composed by magnesium oxide(MgO) mainly, is made by magnesite calcined at high temperatures, prolific in Liaoning and other areas. The advantages of dealing wastewater with light buring powder are aboundant raw materials and low cost. This paper adopted the light calcined powder as precipitating agent because of abundant raw materials and low cost. At the same time, the simulated wastewater, which contained the nitrogen and phosphorus was studied using the magnesium ammonium phosphate precipitation method.This experiment adopted the chemical precipitation method, adding the light calcined powder to wastewater which contained the nitrogen and phosphate, and at last, the ammonia nitrogen and phosphorus in the form of magnesium ammonium phosphate (MAP) precipitation.. In the pilot study process, water distribution for the study, through a large number of experiments to determine the process conditions when the nitrogen and phosphorus removal is best. The process conditions included N:P ratio, light burning powder dosage, pH, reaction time and the settling time required after the end of the reaction, and to optimize the test under the optimum process conditions. Second, the same water distribution for the study, using the magnesium ammonium phosphate precipitation method to study the different concentrations of ions was effect on the removal rate of nitrogen and phosphorus. Third, using the magnesium ammonium phosphate precipitation method to deal with the water, which come from a certain building inspection experimental wastewater and record the data. At last, the reaction kinetic analysis to verify the feasibility of this method. The main experimental results can be listed as follows:(1) The rate of nitrogen and phosphorus removal was basically stabilized when adopted the light burning powder as precipitant to deal with the wastewater under the situations of the quality ratio of light burning powder and phosphate was10:1and the ratio of N:P in wastewater was0.6(2) Selecting the proportion of nitrogen and phosphorus in the water to study different values of pH was effect on the light burning powder to deal with the nitrogen and phosphorus in wastewater. The removal rate of nitrogen and phosphorus reached a higher value when the initial pH value was3-5and the reaction equilibrium pH was9-10(3) Study at the impact on the removal rate by different concentrations of anions and cations during removing phosphorus and nitrogen from simulated wastewater. The results show that:the anions almost haven’t effect on the removal rate, while the effect of cations on removal rate is greate.(4) Three parallel groups were done under the optimum condition, which the ratio of nitrogen and phosphorus was0.4. And the experimental data showed that the removal rate of nitrogen and phosphorus was99.32%and94.21%, respectively under the best treatment.(5) Appling light burning powder to deal with the actual wastewater, the removal rate of phosphorus was more than95.41%and the removal rate of nitrogen reached to92.47%.