Study On Preservation Method Of Dry Powder Agent Of Anammox Mixed-Culture

Compared with conventional denitrification technology,anerobic ammonium oxidation(Anammox)process is no need of external organic carbon source and oxygen demand.It creats low sluge and saves cost.Thus,Anammox process has been gradually applied to the field of wastewater denitrification.However,due to the slow growth rate of Anammox bacteria,with doubling time about 11 days,it results in a slow start-up time for treatment process.Hence,preserving Anammox bacteria and providing sufficient quantity of Anammox biomass become the key to industrial application of Anammox process.The vacuum drying method was been used to prepare the dry powder agent of Anammox bacteria which was preserved at 4? and protected from light and air later in this study.Meanwhile,influence factors that may affect preservation were filtered,optimized and investigated.The main results are as follows:(1)Among alternative dry protective agents of polyving akohol,carboxyl methyl cellulose,deionized water,sodium alginate and trehalose,sodium alginate is the most suitable.After preservation for 30 days,its survival rate and ratio between Anammox bacteria and eubacteria were the highest,respectively achieving 99.8% and 47.5%.Meanwhile,at the batch experiment,its bacteria hydrolysis time was 2 days.And its colour of suspension was the closest to the flesh bacteria suspension which was auburn.(2)Using sodium alginate as the drying protective agent and preserving for 30 days,when the drying temperature was 60?,the drying time was just 6 hours.Meanwhile,the sundry bacteria was less and its survival rate reached 96.4%.The bacteria hydrolysis time was just 1 day.Meanwhile,the averge total nitrogen(TN)removal efficiency was 36.1% in the rejuvenation batch test.Thus,60? was the best optimal.At the process that optimizing the concentration of sodium alginate,3% was the most suitable.The colonial morphology of Anammox bacteria was the least destoryed and its TN removal efficiency of continuous experiment was the highest.Meanwhile,the bacteria activity was recovered to 41%.(3)The dry powder agent of Anammox mixed-culture was better rejuvenated without adding KNO3 solution;and constant low temperature environment was more suitable for preservation,room temperature could easily cause putrefaction of sodium alginate and multiplication of other kinds of bacteria.With the preservation time to extend,the activity recovery of Anammox bacteria was more difficult to realize.