The Treatment Technology Of Organic Matter And Ammonia Nitrogen In Micro-polluted Water Source In Northwest Rural Area

In northwest China,there is little rain and drought and drinking water sources are scarce.Slight excess of permanganate index and ammonia nitrogen water quality index occur from time to time in rural water sources,micro-pollution of drinking water sources is quite common.The city commonly used water treatment technology can not meet the actual situation of rural micro-polluted water treatment.In view of the slight over indicators of permanganate index and ammonia nitrogen water quality index of the water source in the northwest rural areas,it is of great practical significance to study the miniaturized,simple and easy to manage treatment process suitable for the use in the northwest rural areas.This project comes from the national key research and development program "integrated technology and application demonstration of water supply and drainage in typical water-deficient areas in western China"--"research and demonstration of key technology of drinking water and sewage treatment in rural areas of HeTao,NingXia(2016YFC0400705)".The main research results are as follows:(1)The effects of different single factors on the removal of permanganate index and ammonia nitrogen in the carrier reactor were investigated.In the experiment,five different suspension carriers were selected for the single factor experiment.According to the comparison of permanganate index and ammonia nitrogen experiment results,the carrier with the best removal effect was finally selected.Study found that the urethane foam carrier in slightly polluted source water in the process of organic matter and ammonia nitrogen treatment showed extremely stable and high efficient degradation ability,therefore the experiment in view of the urethane foam carrier biofilm reactor for the single factor influence research,finally it is concluded that the reaction cycle for 6 h,dissolved oxygen for 3 to 5 mg/L,pH is 8-9,filling rate is 20%,under the running parameters of can be concluded that the removal rate of permanganate index was 89% and ammonia nitrogen removal rate was 85%,potassium permanganate concentration in produced water is 2 mg/L,ammonia nitrogen concentration of 0.09 mg/L,meet the surface water Ⅱ level of water quality standards.(2)Three different chemical oxidants potassium permanganate,sodium hypochlorite and ozone were used to treat organic matter and ammonia nitrogen in slightly polluted water.The application of box-behnken method in response surface software for central combination design has investigated the effect of the interaction of the amount of oxidant,mixing time and pH on the removal of organic matter and ammonia nitrogen in water by chemical preoxidation.The related quadratic polynomial mathematical model was established,and the removal rates of organic matters and ammonia nitrogen were taken as the response values.It was determined that the removal rates of organic matters and ammonia nitrogen were 56.3% and 18.6% respectively under the conditions of potassium permanganate dosage of 9.3mg/L,stirring time of 33 min and pH of 9.0.The effective chlorine dosage of sodium hypochlorite was 5mg/L,the mixing time was 30 min,the mixing rate was 300r/min,and the pH was 4.The optimal intake organic load was 10-16 mg /L.Under this condition,the average removal rate of organic matter and ammonia nitrogen by sodium hypochlorite reached 43.2% and 11.4%,respectively.;Ozone dosing quantity 3.9mg/L,33 min contact time,pH 7.5,under the condition of the organic matter and ammonia nitrogen removal rate was 44.1%,36.6% respectively,the potassium permanganate index,ammonia nitrogen in water meet the surface water Ⅱ level of water quality standards.(3)The removal efficiency of organic matter,ammonia nitrogen,turbidity,UV254 and other water quality indexes in the slightly polluted rainwater with high turbidity by coagulation precipitation method using PAFC as coagulant was investigated.The optimal parameters were determined by the addition of coagulant,mixing time,pH,precipitation time and other single factors.The application of box-behnken central combination design method in response surface software can investigate the influence of the interaction of coagulant dosage,mixing time,pH,precipitation time,precipitation specific surface load and other factors on the removal of pollutants such as permanganate index,ammonia nitrogen,UV254 and turbidity by coagulation precipitation method.The related quadratic polynomial mathematical model was established,and the removal rates of permannate index,ammonia nitrogen,UV254,turbidity and so on were taken as the response values.The addition amount of PAFC was determined to be 1.5ml /L,the pH was 8.5,and the mixing time was 23 min.Under the condition of the reaction,permanganate index,ammonia nitrogen,the removal rate of turbidity,UV254,respectively,69.4%,36.5%,99.9%,70.8%,the potassium permanganate index,ammonia nitrogen in water to fulfill the requirements of the quality of the surface water environment quality standard Ⅱ level.