Research On Pretreatment Techology For ADC Ammonia-Nitrogen Wastewater

Water pollution is regarded as one of the most serious problems, for the reason that a lot of waste water and solid waste are generated with the rapid development of industry in recent years. Ammonia-nitrogen wastewater can cause very severe harm to the natural environment. It contributes to the eutrophication, damaging the balance of eco-system of water environment. Ammonia-nitrogen in water mainly comes from the exerements of people and animals, the loss of chemical fertilizer in farm, gas production, coking process, metallurgy industry and lanfill leachate. Ammonia-nitrogen wastewater at high concentration can be generated during the production process of ADC (azobisformamide) foaming agent, which is very complicated for treatment. Therefore, research on the treatment of ammonia-nitrogen wastewater, especially the organic contaminants, is still a challenge in wastewater treatment research field. This work investigated the pretreatment process of the organic nitrogen wastewater in the production of ADC with potassium monopersulfate and chlorine dioxide. Main tasks are as follows:1) Biurea were prepared by hydrazine and urea under acidic conditions. Synthesis conditions were optimized to promote the utilization of hydrazine hydrate and enhance the production rate. The experimental data was analyzed and discussed, and the optimum reaction conditions were determined.2) Factors of influencing chlorine dioxide(ClO2) treatment of organic nitrogen wastewater were studied. Experiments showed that chlorine dioxide can remove the organic nitrogen in ADC wastewater efficiently, and chlorine dioxide only reacts with organic ammonia in the entire treatment process. For 100 mL ADC wastewater with CODCr of 667.6 mg/L,78.7% CODCr removal could be achieved in 30 min at 60℃, with 10 mL chlorine dioxide.3) The pretreatment process of the organic nitrogen wastewater by potassium monopersulfate was studied as well. Effects of the adding amount of potassium monopersulfate, reaction temperature, reacting time and pH on the pretreatment process have been explored. It showed that potassium monopersulfate can remove the organic nitrogen in ADC wastewater efficiently. For 100 mL ADC wastewater with CODCr of 702.99 mg/L,95.3% CODCr removal could be achieved in 10 min at 60℃, with 2.5 g potassium monopersulfate.