Migration And Transformation Of Ammonia Nitrogen In Reclaimed Water In A Circulating Cooling System

With the development of China's modernization process,the contradiction between supply and demand of water resources has become increasingly fierce.While the water demand for explosive growth,and the other side is the depletion of water resources,pollution.At this time,the supply of urban reclaimed water as a circulating cooling system has become one of the important measures to solve the water shortage.However,the quality of urban reclaimed water is complex,and nitrogen is one of the important factors related to the scaling,corrosion and microbial growth of the circulating cooling system.In this paper,urban reclaimed water is used as the research object of ammonia nitrogen in the recharge water.Through the designed circulating cooling experimental device,the effects of conventional conditions on the ammonia nitrogen form transfer in the circulating cooling system and its system on scale corrosion are investigated.The improved extraction method of phosphorus in the sediment of riverbed was used to analyze the different forms of sediment in the sediment scale,and the extraction method of nitrogen in the sediment scale of the circulating cooling system was established.The form and content of nitrogen in the liquid-solid phase of the circulating cooling system were studied.Analytical determination was carried out to summarize the migration and transformation of ammonia nitrogen in the circulating cooling system and the effect on system fouling corrosion.The results show that the nitrogen extraction method can be applied to the extraction of nitrogen in the sediment scale of the circulating cooling system.The recovery rate of nitrogen in the system scale is 96.5%,and the recovery rate is high.The optimized method can effectively recover and determine different forms of nitrogen in the sediment scale.There are two forms of nitrogen in the sediment scale of the circulating cooling system,namely ionic exchange nitrogen and carbonate bound nitrogen.Temperature and concentration ratio are the main factors affecting the migration and transformation of ammonia nitrogen in the circulating cooling system.With the increase of temperature,the proportion of ionic exchange nitrogen in the sediment scale increases slightly from 10.26% to 10.53%.The proportion of nitrogen in sediment scale decreased slightly from 89.76% to 88.56%.With the increase of concentration ratio,the proportion of ionic exchange nitrogen in sediment scale decreased slowly,and the proportion of carbonate-bound nitrogen in sediment scale The ratio increased,the proportion of ion exchanged nitrogen decreased from 10.5% to 7.79%,and the proportion of carbonate bound nitrogen increased from 89.26% to 91.88%.Different conditions have different effects on the system.Under different temperature conditions,the system fouling amount and ammonia nitrogen migration and transformation are highly correlated.The higher the temperature,the higher the ammonia nitrogen transfer rate,the larger the system fouling amount.Under different dosage conditions,the dosage of ammonia nitrogen increased,the consumption of bicarbonate in water,the alkalinity of the system was reduced,and the amount of system fouling decreased.Under the condition of concentration ratio,the higher the concentration ratio,the higher the scale ion concentration,and the larger the system fouling amount.However,the concentration ratio is between 2 and 3,and the ammonia nitrogen concentration in the system is lower than 2 mg/L.The metal corrosion rate does not change significantly,and the corrosion is suppressed.