Treatment Of High Concentration Ammonia Nitrogen Wastewater By Stripping Plus MAP Combination Process

As a kind of common sewage that is difficult to treat,high-concentration ammonia-nitrogen wastewater has been the focus of research in environmental engineering at home and abroad.With the improvement of China's requirements for wastewater discharge standards,traditional treatment processes are increasingly difficult to meet the needs of ammonia nitrogen wastewater treatment.As a high-efficiency ammonia nitrogen pretreatment process,the stripping method has been widely studied and applied in the field of industrial wastewater treatment.However,the relevant research directions in China mainly focus on the optimization of relevant process conditions and parameters in the stripping process,and no blowing equipment.The structural design and the influence of relevant parameters on the removal rate of ammonia nitrogen were further explored,and the post-treatment process of ammonia nitrogen wastewater after stripping was not discussed.Based on the discussion of the mechanism of gas-liquid mass transfer in the process of stripping,the calculation formula of the relevant structural parameters of the stripping tower is deduced,and the treatment effect of the high-concentration ammonia-nitrogen wastewater by the stripping plus MAP combination process is studied experimentally.The effects of several main factors on the stripping experiment and the MAP experiment were investigated.The main conclusions were as follows:?1?Based on the investigation of the mass transfer mechanism between gas-liquid two-phase in the mass transfer process between gas-liquid two phases in the stripping tower,the calculation of the volumetric mass transfer coefficient of the ammonia-nitrogen stripping tower was carried out,and the blow-off was derived therefrom.The calculation formula of the height of the tower packing layer calculates the pressure drop of the stripping packed tower.?2?In the laboratory self-priming stripping device,the ammonia nitrogen in the high concentration ammonia nitrogen wastewater was removed by the stripping method.The influencing factors such as air flow rate,influent flow rate,wastewater pH value,wastewater temperature and initial ammonia nitrogen concentration of wastewater were successively tested by single factor experiment.The mass transfer volume coefficient of the stripping process under various conditions was calculated,and the influence law of each factor on the mass transfer volume coefficient was obtained.The mechanism of removing ammonia nitrogen by stripping method was further discussed,which provided the design of the stripping equipment.A certain amount of data support.In the experiment,the suitable process conditions for removing high-concentration ammonia-nitrogen wastewater by stripping method were determined.The air flow rate was 40m3/h,the influent flow rate was 25 L/h,the wastewater pH value was 11,the wastewater temperature was 60°C,and the packing layer height was 1.2m.The pumping efficiency of the Pall ring stripping tower is superior,which is 86.83%.?3?The factors affecting the effluent of ammonia nitrogen after stripping were investigated by single factor experiment under laboratory conditions,including the pH value of wastewater,the proportion of chemical precipitant,the stirring time and the precipitation time.The influence law of ammonia nitrogen removal rate of wastewater is obtained,and the suitable operating parameters in the experiment of MAP precipitation method are obtained:The pH of the wastewater was 10.5,c(Mg²⁺):c?NH₄⁺?:c(PO₃^4-)=1.15:1.0:1.15,the stirring rate was 200r/min,the stirring time was30 min,and the precipitation time was 30 min.The ammonia nitrogen removal rate of the effluent after stripping under this operating condition can reach 91.50%.