The Industrial Study On The Removal Of High Concentration Ammonia Nitrogen From The Vanadium Sesquioxide Wastewater

Air stripping had been studied to remove the high concentration of ammonia-nitrogen (NH3-N) from vanadium sesquioxide (V2O3) wastewater in this project.High concentration of ammonia-nitrogen wastewater was drained off in the production of vanadium sesquioxide (V2O3) in Panzhihua Steel Group Panhong Vanadium Production Ltd. If this wastewater were emitted into Jinsha River directly, the water system would be deeply suffered. Biotechnology and physic-chemical technology can be used to remove ammonia-nitrogen from wastewater. Air stripping had been selected to deal with wastewater after considered feasibility of technology and economy. Air stripping, featured with low capital, low operating cost, simple installation and ease retrofit, was emerged as an available NH3-N control technology, which is suited for the industrial application.In this study, involving mechatiism investigation, the bench-scale experiment, middle experiment and industrial research, the results showed that the value of pH, the temperature and the time of air stripping were three main factors that could effect the efficiency of removing NH3-N. At the temperature of 80 , the PH of 11.5 and the removal time of 90min, the average concentration of NH3-N in outlet water was 8.98mg/l, which was satisfactory for grade- I of Integrated Emission Standard of Wastewater (GB8978-1996). By delaying the removing time, the concentration of NH3-N in the wastewater could be decreased under lmg/1. CODcr and SS had also been removed in this process. The average concentration of CODcr in outlet water was 37.5 mg/1, and the average concentration of SS was 14.5 mg/1. The value of pH in outlet water was higher than grade- I of Emission Standard (6-9), so this water were not permitted to emit. But a certain quantity of the water could be reused in the working procedure of hydrolyzing calcareousness, and the remains could be reused as washing water or emitted directly after neutralization by acid. The volatilized ammonia in removing process had been absorbed completely by using vitriol, which could produce dilute ammonium sulfate that should be reused in washing process in V2O3 production, which could avoid secondary pollution. This studyfocused on the discontinuous experiment. The continuing removing system would be realized if several equipments were operated as asynchronous working.Undoubtedly, this study provided the theoretical guidelines and quantitative basis for the engineering design of removing the high concentration of NH3-N from wastewater by air stripping. If the removing system was set up, it could save 2.965 million Yuan for Panhong Vanadium Production Ltd. every year, and 1555.2 ton NH3-N would be cut down that were not emitted into Jinsha River.