| Nitrogen pollution seriously threatens the ecological balance and human health,and sewage denitrification has become a top priority.However,the traditional N-removal technology simultaneously has the disadvantages of increasing greenhouse gas emissions and high energy consumption during reducing pollutants,developing new low-carbon and high-efficiency technologies becomes extremely urgent.In recent years,anaerobic ammonium oxidation(Anammox)technology has demonstrated attractive potential.However,the current research is mainly aimed at high-concentration nitrogenous wastewater.There are few reports on the research and application of Anammox in urban sewage.In the aspects of rapid enrichment of functional bacteria,enhancement of efficiency and stable operation at low temperature and low concentration have yet to be broken.This study focuses on the two types of sewage involved in urban sewage treatment,and explores the rapid enrichment of anammox bacteria as the starting point.The main research contents are efficiency enhancement,process operation.The N-removal performance and operation of Anammox granular sludge process were explored under different conditions.At the same time,Scanning Electron Microscopy,Transmission Electron Microscopy,MiSep High-throughput Sequencing and In-situ Fluorescence Hybridization were used to analyze the characteristics and microbial community structure of granular sludge,and to explore the Key factors which influence the N-removal efficiency of granular sludge.This study will provide basic data and theoretical guidance for the rapid enrichment,efficiency enhancement and process operation of Anammox in urban sewage treatment.In order to accelerate the process of enrichment for functional bacteria,an enrichment strategy was developed and the characteristics of the process and microbial community structure were investigated.Showing that the N-removal rate of 359.44 mgTN/(L·d)was obtained on the 97 th day of the control group,and the Anammox genus Candidatus Kuenenia was cultivated on the 121 st day,accounting for 30.20%,indicating that the enrichment strategy was successful.On the 42 nd day of the experimental group,the Nremoval rate of 455.36 mg TN/(L·d)was obtained.On the 60 th day,Candidatus Kuenenia was also cultivated,accounting for 37.25%,which was significantly higher than the reported level,further demonstrated the success of the enrichment strategy.At the same time,it was confirmed that the addition of trace(1/1000)functional bacteria can significantly accelerate the enrichment process,showing excellent engineering value.In order to enhance the denitrification efficiency Anammox,this paper cultivated Anammox granular sludge under high concentration conditions.The results showed that after 270 days and 372 days of operation,the P-1 and P-2 reactors successfully cultivated granular sludge with particle size of 1.0-1.6mm,and the degree of granulation was as high as 99.56% and 99.68%,achieving the performance.The enhanced denitrification rate was as high as 8427.61 mg TN/(L·d)and 10055.11 mg TN/(L·d),and the HRT was as short as 2.4 h and 2.16 h,showing excellent engineering significance.It reveals the importance of the proportion of influent matrix,confirms the reliability of the traditional ratio(1:1.32),achieves efficient and stable operation of ultra-high concentration(1700 mg/L)nitrogenous wastewater,and has a TN removal rate of 88.32%.The rate is as high as 12,0 68.74 mg TN/(L·d).Revealing the excellent properties and th microbial community structure of Anammox granular sludge The density was 1.027-1.048 g/mL,the average sedimentation rate was 107.53 m/h,VSS was as high as 51418.57-70000.00 mg/L wet sludge;"cluster" shape;the total EPS is 529.13 mg/gVSS,mainly protein;the proportion of Planctomycetes and Kuenenia are as high as 57.38% and 54.04% respectively;the FISH results show the Anammox bacterias are distributed throughout the whole particle.Above all,the essences of high-efficiency N-removal performance of granular sludge are revealed.The low-temperature and low-concentration(LT-LC)reaction system was constructed,and the performance of the Anammox granular sludge process in treating urban mainstream sewage was further studied.The results show that the TN removal rate is as high as 89.90%-90.27% and the effluent TN is as low as 5mg/L for 141 days' operation,which is far lower than the first-class A standard,solving the problem of effluent discharge.The N-removal rate exceeds 900 mg TN/(L·d),which is close to 2 times of the conventional process,and the HRT is 1.19 h.The characteristics and microbial community structure of the Anammox granular sludge at LT-LC were revealed.The particle size remained stable at about 0.89 mm,the density was 1.017-1.027 g/mL,the average sedimentation rate was 32.92 m/h,and the VSS value was 38000.00-43000.00 mg/L wet sludge,the functional bacteria maintain the clustering characteristics,the stability is weakened,the total EPS reach 255.52 mg/gVSS,mainly protein,the proportion of Planctomycetes and Kuenenia is 26.58% and 21.41%,and the Anammox bacteria are distributed throughout the whole particle.revealing the adaptability of granular sludge in low temperature,proving the feasibility of treating LT-LC urban sewage from different angles,showing broad engineering application prospects. |
PDF Full Text Request