Study On Removal Of Ammonia Nitrogen From Black And Odorous Water Treated By Magnetic Separation System

At present,the black and odorous water problem in many cities of China is worsening,inviting urgent solutions.Magnetic separation technology possesses the feature of small area coverage and is capable of quick and efficient treatment of black and odorous water.However,the removal efficiency of ammonia nitrogen is very poor.A method for efficient removal of ammonia nitrogen from black and odorous water treated by magnetic separation system needs to be explored which is of important practical significance for further improving the treatment process of black and odorous water.This paper mainly introduces chlorine oxidation and zeolite adsorption,which can be employed to remove ammonia nitrogen from black and odorous water treated by magnetic separation system.The main research content and conclusions of the study are as follows:?1?This paper studies the effects of magnetic separation technology combined with chlorine oxidation process on the removal of ammonia nitrogen in black and odorous water.Single factor experiments are carried out to change the water's pH,NaClO dosage,reaction time,then the NH₄⁺-N value of supernatant is measured to investigate the effects of various factors on the removal of ammonia nitrogen by sodium hypochlorite and to determine the optimum reaction conditions.The optimum reaction condition is pH,7⁸,reaction time is 20min,and the optimum molar ratio of sodium hypochlorite to ammonia is 1.2:1.In which condition,COD average removal rate is 76.1%,SS 88.55%,TP 90.6%,TN 38.5%,NH₄⁺-N 72%,NO₂^--N 83.2%.Yielding water indicators are stable.?2?This paper studies the effects of magnetic separation technology combined with zeolite adsorption on the removal of ammonia nitrogen in black and odorous water.Comparison,modification and isothermal adsorption experiments show that the effect of artificial zeolite adsorption of ammonia nitrogen is good.The adsorption isotherm can be described by using the Freundlich model,the adsorption isotherm equation is:q_e=1.1275C_e^0.6871.Single factor experiments are carried out to change the water's pH,artificial zeolite dosage,particle size of zeolite,temperature and reaction time,then the NH4⁺-N value of supernatant is measured to investigate the effects of various factors on the removal of ammonia nitrogen by artificial zeolite to determine the optimum reaction conditions.The optimum reaction conditions are as follows:the initial pH is 7⁸;the reaction time is 20min;the optimum dosage of synthetic zeolite is 600g/?gNH4⁺-N?;the optimum particle size is 40⁶0 mesh.In which condition,COD average removal rate is71.93%,SS 88.55%,TP 88.7%,TN 44.33%,NH₄⁺-N 70.5%.Yielding water indicators are stable.?3?The study of the dynamics of the two processes shows that the reaction process of sodium hypochlorite and ammonia nitrogen meets the characteristics of two stage kinetic reaction,in which 78.42%of the ammonia nitrogen is converted to nitrogen;and that the kinetic characteristics of ammonia nitrogen adsorption on artificial zeolite is in accordance with the pseudo-second order kinetic model,the adsorption process mainly depends on ion exchange.?4?The comparison study of the treatment effects and cost estimation of the two combined processes shows that the magnetic separation technology combined with chlorine oxidation combined process is a better choice in treating urban black and odorous water.The project investment cost is lower and its operation is more viable,it is thus more suitable for treatment of urban black and odorous water.