The Treatment Technology Of High Ammonia Nitrogen Wastewater

The high ammonia nitrogen wastewater from pharmaceutical industry has large discharge,high organic content,high salt content,complex impurity composition,and large differences between different batches,which is difficult to be treated by homogenization methods,and it is difficult to reach the discharge standard and cause a large amount of recoverable resources to be wasted in the wastewater by using traditional ion exchange,Folding Point Chlorination;Anaerobic;Aerobic and other treatment methods and combined processes.The use of The Integrated Process of Distillation-Membrane Separation to treat high ammonia nitrogen wastewater can effectively improve the efficiency of wastewater treatment and achieve the reuse standard of industrial cooling water as stipulated by the national standard while effectively recovering ammonia nitrogen and water resources,which has high industrial application value.In this paper,The Integrated Process of Distillation-Membrane Separation was used to treat high ammonia nitrogen pharmaceutical wastewater from the oxime extraction section of azithromycin.This paper researched the effects of the distillation column on the removal rate and ammonia recovery rate of high ammonia nitrogen wastewater,the effects of different pretreatment methods on the removal rate of total impurities in wastewater,the effects of different RO process combinations on the retention effect,membrane flux and effluent rate of pretreated wastewater,and the effects of The Integrated Process of Distillation-Membrane Separation on the total treatment effect and resource recovery of high ammonia nitrogen wastewater.Through the study of total hardness,COD,ammonia nitrogen,pH,conductivity,membrane flux and water yield rate of pharmaceutical wastewater,the feasible application of The Integrated Process of Distillation-Membrane was determined,and the main conclusions are as follows:（1）The content of wastewater with high ammonia nitrogen was reduced from 4 000～6000 mg·L^-1 to 300～400 mg·L^-1 after the distillation operation,and the average removal rate of ammonia nitrogen reached 96.11%,and the ammonia nitrogen content at the top of the tower was 80,000～100,000 mg·L^-1,and the average recovery rate of ammonia nitrogen reached 96.98%.（2）In the pretreatment process,absorbance method was used to characterize the total content of non-aqueous components in wastewater:the highest total impurity removal rate of flocculation precipitation was 43.75%,and the treatment time was shorter,but the salinity removal rate was only 3%～8%;the highest total impurity removal rate of activated carbon adsorption was 35.04%,and the removal effect of activated carbon adsorption on salinity and other removal was better,and removal rate could reach 46.98%;the energy consumption of pretreatment by distillation method was higher,but the treatment effect was much better than the other two pretreatment.The distillation method for pretreatment has higher energy consumption,but the treatment effect is much better than the other two pretreatment methods,with the average removal rate of salinity reaching 89.49%;the distillation obtained from the distillate is clear and transparent,and the removal rate of suspended particulate matter,color,turbidity and other indicators can be considered almost 100%,the average removal rate of COD reaching 93.75%,and the average removal rate of total hardness reaching 99.1%,which can meet the feed water quality requirements of RO process.（3）The secondary two-stage recirculation RO process has more obvious advantages than other types of RO combination process.The average retention rate of ammonia nitrogen and conductivity are 97.36%and 99.39%,respectively,and the total hardness is also in the overall trend of reduction,and all three indicators of the secondary RO effluent meet the reuse standard of industrial cooling water,but the average retention rate of COD is low,only86.83%,and the average effluent COD content is 294.9 mg·L^-1,which still needs post-treatment before it can be reused.The average COD content of the effluent was 294.9 mg·L^-1,which still required post-treatment before reuse.Compared with other RO combination processes,the secondary recirculation process enables the wastewater to be fully recycled,and the average effluent rate of the secondary RO permeate is 38.1%,so that a large amount of water can be recycled.The secondary RO permeate effluent was treated by activated carbon adsorption column,and the COD content was reduced by 83.63%;the conductivity was reduced by 88.41%;the pH was nearly neutral and within the standard range;the total hardness was reduced by 84.21%.（4）After the high ammonia nitrogen wastewater is treated by The Integrated Process of Distillation-Membrane Separation,the main pollutant indexes:total hardness,COD,ammonia nitrogen,pH and conductivity can meet the industrial water standard for municipal wastewater recycling.The concentration of ammonia nitrogen at the top of the distillation tower is 80,000～100,000 mg·L^-1,and the average recovery rate of ammonia nitrogen at the top of the distillation tower is 96.58%,which can basically meet the enterprise’s demand for concentrated ammonia water,and the average value of ammonia nitrogen in the kettle liquid of the tower reduce to 324.85 mg·L^-1,which enters the system for circulation,and most of the ammonia nitrogen in the circulation is discharged through the primary RO process concentrate,this part returned to the distillation tower feed storage tank to continue refining recovery.The average water recovery rate in the RO process is 32.88%,and this part of the effluent is treated by the activated carbon fixed bed and then reused to meet the standard,and the comprehensive water recovery rate of RO-fixed bed is 31.88%.The solid product precipitation rate of inorganic salts and organic crystals obtained from the evaporation tower kettle is about 21.32%,and this part of solid product can be recovered through subsequent analysis to determine the recovery scheme.The Integrated Process of Distillation-Membrane Separation achieves resourcefulness,reduction and harmless treatment of high ammonia nitrogen wastewater,and nearly achieves zero discharge.