Study On Modified A~2/O-Ozone For The Co-treatment Of Pharmaceutical Tail Water And Domestic Wastewater

In recent years,pharmaceutical industry has maintained a rapid growth trend,and its environmental pollution problems cannot be ignored.Pharmaceutical wastewater is common in water quality and water quantity variations,complex composition,and poor biodegradability and so on,and the traditional biological treatment cannot meet the discharge standards.Therefore,various physcochemical and biochemical coupling technologies have showed advantages and achieved good results in pharmaceutical wastewater treatment.In this paper,based on the previous analysis of wastewater,Sulfadiazine(SD)was chosen as the typical pharmaceutical pollutant and bench scale treatment experiments were carried out,and then the pharmaceutical tail water and domestic wastewater were mixed with different ratios,and improved A2/O-ozone was adopted to treat the mixed wastewater,the changes of microbial population in biochemical reaction stage were also analyzed.The conclusions were as follows:(1)Ozone was used to carry out experiments on SD degradation.It shows that the solution pH,ozone concentration and anion HCO3-affect the degradation process of SD.The removal rate increases with the increase of the solution pH value,and the increase of the ozone concentration can effectively improve the degradation rate of SD.The HCO3-in water has a certain effect on the degradation of ozone.The SD degradation process was basically in accordance with the pseudo-first-order kinetics model.When the SD concentration was 30mg/L,the initial pH was 9.14,the ozone concentration was 10mg/L and the HCO3-dosage was 100mg/L,the SD was almost completely degraded.And the mineralization rate was 39.44% after 120 min.C6H7NO3S was one of the degradation products proved by LC-MS analysis.C6H7NO3 S was further mineralized into carbon dioxide under ozone.(2)Pilot test was carried out to treat the mixture of pharmaceutical tail water and domestic wastewater in different ratios,which achieved certain effects by taken ozonation as pretreatment and enhanced treatment.Under the two conditions,the two kinds of water were mixed in different ratios;the effluent could meet the level A discharge standards of the national urban wastewater in terms of ammonia nitrogen,total nitrogen and phosphate after treatment;therefore the biological stage has showed good performance.Taking ozonation as pretreatment unit,relatively good COD removal effect was attained with 30% pharmaceutical tail water in the mixture;while taking ozonation as post-treatment unit,the best COD removal effect was accomplished with 20mg/L ozone concentration and 37 min contact time.With a pharmaceutical ratio of 50% and ozonation as the pretreatment unit,the reduction efficiency of aromatic protein Ⅰ was the largest,reaching 45.33%;when taking ozonation as the post-treatment unit,the humic reduction was the largest,reaching 87.09%.(3)The microbial community structure of the modified A2/O system was detected by high-throughput macro-genome sequencing technique.Taking ozonation as the pretreatment unit,the microbial community diversity was higher in the system and the species uniformity was higher than that of the ozone of the species uniformity;however in general,the total number of species in the ozonation post-treatment was more than that of the ozonation pretreatment.The effective sequences in each sample of the ozonation pretreatment or the ozonation post-treatment were classified from the phylum,the class,the order,the family and the genus.A total of 344 genera,135 families,67 orders,45 classes and 29 phylums were detected in the ozonation pretreatment while correspondingly 363,143,51 and 34 were classified in the ozonation post-treatment.Based on the analysis of the dependence level,Thauera and Methyloversatilis were the dominant species in the ozonation pretreatment,which played a key role in the removal of phenol and COD from wastewater.Parasegetibacter bacteria were the dominant species in the ozonation post-treatment.In this paper,through the bench scale and pilot tests,the treatment of pharmaceutical tail water achieved good results,and the effluent could meet the discharge standards,which provides us some references for pharmaceutical and other industrial wastewater treatment.