Experimental Study And Application On Treatment Of High Concentration Ammonia-Nitrogen Wastewater By Air Stripping With Super Gravity Technology

With the rapid development of economy and the acceleration of industrialization, the increasingly serious environmental pollution has become one of the most urgent problems to be solved at present. Due to large amount of discharge, high concentration and complex composition, high concentration ammonia nitrogen wastewater produced in the process of life and industrial production leads to eutrophication and the decline of water dissolved oxygen, and the death of water biological, which seriously affect human health and restrict the development of economy and society.Aiming at the problems of low efficiency of denitrification, secondary pollution and other issues, this paper introduces a new type of combined treatment process- "air stripping +super gravity".In order to reach the first level emission standards of residual ammonia nitrogen concentration under 15 mg/L,the process make full use of characteristics of high nitrogen removal efficiency,convenient operation,low treatment cost of air stripping to pretreat wastewater,then by using the advantage of enhancing mass transfer process of the super gravity, the wastewater is treated in depth.This paper takes the high concentration ammonia nitrogen wastewater generated by a mining enterprise as the research object, the wastewater concentration in 10000~20000mg/L, studies various influencing factors on the removal of ammonia nitrogen and gets the most appropriate condition of the experiment.Under the conditions that pH value is 11, temperature is 40℃, denitrification reagent dosage is in the dosage of 50mg/L, the mixing time of composite denitrification reagent with wastewater is 30 min,stripping time is 1 hour and gas-liquid ratio is 2500, the removal rate of ammonia-nitrogen is almost 99%.The experimental results show that the residual ammonia nitrogen concentration is above 15mg/L, which can not reach the standard of first grade. So the process introduced super gravity technology to treat the wastewater deeply. The pilot study on the treatment of concentration ammonia nitrogen wastewater by super gravity technology shows that under the conditions that pH=13, temperature is 50, gas-liquid ratio is2000, denitrification reagent dosage is in the dosage of 60mg/L, the wastewater concentration declined to 8mg/L from 500mg/L, nitrogen removal rate reached 98.4%, which meet the requirements of the first grade. In addition, the process is also provided with ammonia recovery and recycling system, which can avoid secondary pollution, make waste profitable,and get good economic benefits.So the wastewater treatment cost is greatly reduced, and thegoals of high efficiency, economy and environmental protection reached.Finally, using the combined process of "steam stripping + super gravity" to treat high concentration ammonia nitrogen wastewater produced in Nankang Mining Company Limited,which verifying the feasibility of engineering application and proving that the "air stripping +super" gravity technology has the advantages of high efficiency, economy, environmental protection,which lay the foundation for the application of industrial production demonstration.