| High organic nitrogen wastewater is one of the most important problems in industrial water treatment due to its complex composition of pollutants and difficulty in biodegradation.The vast majority of organic nitrogen in the wastewater can not be in the form of inorganic nitrogen to eradicate through biological nitrification and denitrification,usually requires a long Hydraulic Retention Time(Hydraulic Retention Time,HRT)anaerobic pretreatment,however pretreatment and could lead to denitrification energy waste a lot of,can’t provide the follow-up denitrification denitrification reaction carbon source,adding the additional carbon source will cause the cost greatly improve the reaction,and the effluent nitrogen emission standard more and more strict,traditional sewage treatment plant process in many times after improvement still can not high organic nitrogen wastewater are stable up to standard.To solve the above problem,two levels of A/O process in the traditional sewage plant organisms based on their packing improvement,produce A new type of denitrification process,two levels of A/O-gets,the compound biological denitrification technology(hybird in reactor,gets)by additive in the reactor aerobic zone biological packing carrier,using the attached growth form A mixture of microorganisms and suspended growth form system composite biological reaction device,effectively combines the advantages of biofilm and activated sludge method,such as chemical fiber wastewater treatment containing organic nitrogen wastewater with high great prospects for development.The main content of this topic is to use two-stage A/O-HBR process to treat N,Ndimethylformamide(N,N-dimehtylformamide,DMF)wastewater containing high organic nitrogen.From optimization of influent carbon source,reasonable distribution of influent carbon source,and strengthen the denitrifying denitrification three aspects from time and space,to adjust the different operating conditions improve process denitrification efficiency,change the influent carbon source and the use of our time,location,extend or enhance denitrification denitrification,and improve the utilization rate of raw water carbon source to reduce the effluent total nitrogen(total nitrogen,TN)concentration,achieve national standards.Specific research contents and results are as follows:(1)In order to solve the problems of insufficient carbon source or high content of organic nitrogen in the effluent caused by excessive or insufficient pretreatment,this paper studies the optimization of carbon source in the raw water.By increasing the effective volume reduced level of anoxic zone partition way,control level of anoxic zone HRT 14 h,12 h and 10 h,respectively,at the same time change the nitrifying liquid reflux ratio(nitrated liquid reflux ratio,R)was 100%,200% and 300%,to conduct a comprehensive test,the level of oxygen in different stages of the research area of raw water quantity of carbon source under different HRT treatment reflux nitrate nitrogen concentration limit and the rest of the use of influent carbon source in the subsequent reaction,provide data support for the actual process.The results show that when the HRT of the first order hypoxia zone is 10 h,the hydrolysis acidification is not complete and has a negative effect on the denitrification of the system,and the effective HRT of the reaction unit is insufficient.When HRT=14 h in the primary anoxic zone,the hydrolysis acidification was sufficient and the carbon source of the primary reaction was sufficient,which only improved the utilization rate of the raw water carbon source in the main denitrification reaction zone.When HRT of the first-level hypoxia zone was12 h,most of the organic nitrogen in the remaining raw water that was not completely reacted remained in the hydrolysis reaction stage,and the raw water carbon source was released step by step in the subsequent reaction,which improved the utilization rate of the raw water carbon source.In the range of HRT=12～14 h and R=100%～200% in the first-level anoxic zone,the removal rate of TN was inversely proportional to HRT in the first-level anoxic zone and directly proportional to the reflux ratio of nitrifying liquid.When HRT=12 h and R=200%,the system denitrification effect was the best,the average TN removal rate was 93.740%,the average effluent nitrate nitrogen concentration was 10.465 mg/L,and the TN concentration was 17.431mg/L.Proteobacteria and Paracoccus were the main functional phylum of microorganisms in the sludge under this working condition.DMF had strong tolerance and TN removal effect was the best.(2)In order to solve the problem of insufficient secondary reaction carbon source and decreased denitrification effect caused by uneven distribution of carbon source,this paper studies the rational distribution of carbon source in raw water.The intake points were respectively set in the first and second level hypoxia zones,and the distribution ratios were 10:0,8:2,7:3,6:4 and 5:5,respectively.The results showed that,starting from the second half of the experiment with a distribution ratio of 8:2,the TN removal rate of the system fluctuated greatly,and the denitrification effect was unstable.When the distribution ratio was 6:4,the denitrification effect was the best,and the average TN removal rate was 89.301%.Under this condition,the main functional bacteria in the reactor was Proteobacteria and Rhodobacter.(3)In order to improve the utilization rate of raw water carbon source in the aerobic zone,the anaerobic denitrification reaction area was increased by adding fillers in the aerobic zone of the reaction unit,and the denitrification reaction area was prolonged in the time.First of all,the performance of high efficiency bio-rope type filler and polyurethane sponge filler in the film hanging stage was tested,and the practicability and stability of the filler were studied.Secondly,the influence of different fillers and different filling rates on the utilization of carbon source of residual raw water and the denitrification effect of the system was studied.The results showed that,for the membrane hanging condition,both kinds of fillers could complete the membrane hanging in about 21 days.Compared with the polyurethane sponge packing,the high efficiency biofilm rope packing had a faster membrane hanging speed,but the impact resistance of organic nitrogen concentration was weaker,and the unit biofilm volume was lower.Through microbial detection,it was found that Proteobacteria was the main bacteria phylum in both the high-efficiency bio-ropetype packing and the polyurethane sponge packing,while Mycobacterium and Denitratisoma were the main bacteria genus,indicating that the two kinds of packing had better degradation effect on the refractory organic nitrogen compounds,and the denitrification and denitrification effect of the polyurethane sponge packing was better.From packing fill rates for denitrification effect,long-term aeration environment,two sets of reactor respectively in efficient biological rope type packing filling rate is 33% and polyurethane sponge filling rate was 18%,achieve the best effect of denitrification,and the latter denitrification effect best,an average of TN removal rate was 93.539%,the average effluent TN concentration is17.817 mg/L. |
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