Screening Of Seeding Sludge For Enrichment Of Anammox And The Start-up Characteristics Of Its Related Technologies

Anaerobic ammonium oxidation process becomes research hotspot in the field of wastewater biological nitrogen removal for its outstanding advantages.However,the full-scale application of the Anammox bacteria is currently hindered by long enrichment time of Anammox bacteria for its low growth rate.Given this,screening of seeding sludge for enrichment of Anammox was carried out,and the start-up characteristics of its related technologies were also conducted.Firstly,the effects of five different kinds of seeding sludge on Anammoxenrichment were investigated,and the relatively more suitable seeding sludge was selected.Sequentially,the influence ofselection pressure caused by the shortening of hydraulic retention time on the start-up performance of Anammox reactor underdifferent influent nitrogen concentration was also carried out.Based on these results,the establishment of the couplednitrogen removal process based on Anammox was explored,and its start-up characteristics were investigated as this process was used for the actual wastewater treatment.The results from the thesis aimed to provide theoretic basis and data support forthe engineering application of Anammox process.The main research contents and results are shown as follows:(1)The sludges for anaerobic treating the wastewater with low C/N are more conducive to the Anammox bacteria enrichment.Different seed sludges have different cell lysis period,activation laged period,activity enhanced period and activity stabilized period during the enrichment of Anammox bacteria.The cell lysis period and activation laged period are longer than the activity enhanced period.Anammox bacteria activity improved fast during the activation enhanced period.The time-consuming of activation enhanced period can be cut down by increasing the total nitrogen loading gradually as soon as possible.(2)Anammox enrichment could be completed in 60 days by virtue of the selection pressure caused by the shortening of hydraulic retention time as SBBR was used as the testing apparatus.The removal load rates of NH4+-N and NO2--N were respective 0.364 and 0.388kgN/(m3·d)as the system was operated under certain conditions(HRT=6h,and NLR=0.8kgN/(m3·d)).As the system was operated under the steady working conditions,the ratiobetween the consumption of NH4+-N,NO2--N and the production of NO3--N was approximately1:1.10:0.36.The activities of SAA and HZO increased with the enrichment of Anammox,and positive correlation was shown obviously between NLR and each of them mentioned.Besides,the results of the related molecular biology also proved that Anammoxdid enrich in the system.(3)A laboratory-scale Anammox reactor was applied to remove nitrogen and organic carbon from swine digester liquor for 150 d.A stable nitrogen removal rate was reached after a three-week adaptation period.The nitrogen loading rate of influent were 0.20±0.04,0.26±0.04,0.26±0.07 kgN/(m3·d)in period I,II and III,respectively.Nitrogen removal rates reached 0.096,0.133 and 0.104 kgN/(m3·d)when the C/N ratios of liquor were maintained at 0.81,0.65,and 1.24,respectively.The Canon process was better than the denitrification process for nitrogen elimination when the C/N ratio of the influent was controlled below 0.8.PCR-DGGE analysis showed a decrease in microbial diversity of Planctomycetes during long-term operation.In contrast,the aerobic ammonium-oxidizing bacteria species were resistant to the changes due to replacement of synthetic wastewater with swine digester liquor.