Study On Starvation Period And Regranulation Of Anammox Sludge Storage

Nitrogen pollution in water seriously endangers human health and safety,and has become a focus of concern.Anammox is a new biological denitrification technology with broad prospects.Compared with traditional denitrification technology,it does not need additional organic carbon source and aeration,and has less excess sludge,which greatly saves the treatment cost.However,due to the excessive doubling time of Anammox bacteria,the start-up of Anammox reactor is slow in practical application.Existing studies have shown that direct inoculation of Anammox sludge is the most effective way to start the reactor.Large quantities of seed sludge produced industrially by Anammox process usually goes through starvation during transportation and preservation,which has an important impact on the recovery process of sludge activity,but the related studies are few.Therefore,this paper studies the effects of starvation on Anammox sludge during storage and compares the recovery process of granules and flocculent sludge after starvation.The effect of ferruginous substrates on sludge storage and recovery of sludge activity after starvation was further investigated.Finally,the sludge re-granulation process was investigated to provide reference for the preservation and recovery of Anammox seed sludge.The main conclusions are as following:?1?The granular sludge formed by the filamentous bacteria as a skeleton and EPS bound to the Anammox bacteria disintegrates after a 10-day starvation period.the results of continuous recovery culture experiments showed that the granular sludge was stronger,it mainly showed that it has the higher nitrogen removal effect and the activity per unit biomass compared with the flocculent sludge in the same starvation period.?2?The addition iron ion causes the sludge to enter the hunger phase earlier during the storage of Anammox bacteria.And it do not have promoting effect on the recovery process of Anammox bacteria after starvation.It may be that the precipitation of Fe?OH?₂ or Fe?OH?₃ inhibits the absorption of the substrate by the cells.?3?The inoculation reactor can be started within 80 days by inoculating the reactor with Anammox sludge,it is disintegrated into flocculation after starvation.After the 160days culture,the reactor has been granulated,the total nitrogen volume removal rate was gradually increased from the initial 14.39 gN·m^-3·d^-1to 150.90 gN·m^-3·d^-1.The kinetic analysis of the reactor shows that the potential maximum volume removal rate of the Anammox reactor was 242.35 gN·m^-3·d^-11 by Monod equation.The inoculated sludge was transformed from brown-yellow flocculent sludge into dark red granular sludge and brown granular sludge.The particle size increases from 0.2 mm to about 1 mm,and Anammox granular sludge is formed successfully during the granulation process.