Research On UV/Chlorine Process For Ammonia Removal And Reduction Of Disinfection By-products

Excessive ammonia is a common problem of drinking water, since it is difficult to be effectively removed, and prone to produce disinfection by-products in the process,it is a problem o f the water treatment. Therefore, the study on efficiently removing ammonia and simultaneously controlling DBPs has important significance.In this study, UV/chlorine coupling process removes ammonia while controlling disinfection by-product formation.This test first determined the breakpoint to the water quality for the present experiment when using breakpoint chlorination method is chlorine to nitrogen ratio 12: 1, and UV/chlorine coupling process has no clear point. Research on the influence of the process parameters such as the amount of chlorine,intensity of ultraviolet light and UV exposure time when using UV/chlorine coupling process methods to remove ammonia and monochloramine in the pilot plant.The results show that the three have a positive effect on the removal of ammonia and monochloramine,which means that increasing the amount of chlorine, ultraviolet light exposure time or the intensity of ultraviolet light are conducive to the removal of ammonia and monochloramine, and when using UV/chlorine coupling process methods,in the case of the ammonia concentration 1.5mg / L of water,only chlorine-nitrogen ratio 5: 1 can remove 75% of the ammonia and achieve the national standard water mark.This experiment studied the impact of p H, dissolved oxygen,natural organic matter on ammonia removal. p H = 7, the ammonia removal is best, partial acid or partial alkaline decreased its removal. Hypoxia or oxygen saturation is not conducive to the removal of ammonia nitrogen. At different concentrations of natural organic matter, at the initial time of the reaction, a lower concentration of natural organic matter removed higher monochloramine,when ultraviolet irradiation time reaching a certain time, monochloramine ’s removal is more or less.For UV/chlorine coupling process, the experiments study on different amount of chlorine,different UV exposure time,different ultraviolet light intensity, different potassium permanganate indexs and different ammonia concentration conditions,the situation of DBPs generation.For UV/chlorine coupling process, the amount of chlorine and ultraviolet light intensity is not important for the generation of DBPs, altering these two parameters, the concentration of disinfection by products is hardly changed;UV exposure time has an impact on the generation of disinfection by-products, to extend the contact time of UV,the amount of disinfection by-products increased.when the influent’s ammonia concentration increases, the amount of disinfection by-products generated a slight increase, but little impact. When the potassium permanganate index concentration increases,the amount of disinfecttion byproducts generated a slight increase.UV/chlorine coupling process can effectively control disinfection by-products, generated very low volume under various experimental conditions, even at high influent ammonia concentrations or high potassium permanganate index,all the indicators’ effluent concentrations were very low, to the indicators which are clearly defined in the relevant standards,effluent co ncentrations are much lower than the relevant national standards.Compare the breakpoint chlorination process and the UV/chlorine coupling process on the removal of ammonia, disinfection and disinfection by-product control, the results show that the disinf ection both are very good;UV/chlorine coupling process may using less chlorine to reach the standards of ammonia and total chlorine than breakpoint chlorination method, the amount of chlorine reduces about 60%.At the same time, UV/chlorine coupling proce ss is signifycantly better than breakpoint chlorination method on the control of DBPs.Ana-lysis the economy of both the two process, UV/chlorine coupling process ’ operating cost is slightly higher than breakpoint chlorination process, but can ensure the safety of the water supply, consider all the factors, UV/chlorine coupling process has advantage in practical applications..Based on the above results of the studies, UV / chlorine coupling process can efficiently remove ammonia, and synchronously control disinfection byproducts,it has good prospects.