Study On Rapid Granulation Of Aerobic Sludge Promoted By Mycelium Pellets

Aerobic granular sludge has many advantages,such as good sedimentation performance,high treatment efficiency,simultaneous nitrogen and phosphorus removal and so on.It is considered to be a promising waste biological treatment technology in the future.However,the technology still has problems such as slow particle formation speed,easy instability during operation,and unclear formation mechanism,which restricts its practical engineering application and promotion.To this end,this study aims to achieve rapid granulation of aerobic sludge and improve its stability,it is proposed that adding mycelium pellets into SBAR reactor as a new method to induce condensation nucleus and promote rapid granulation of aerobic sludge.Adding mycelium pellets into SBAR reactor of conventional activated sludge,the effects of 20g,50g and 80g wet weight mycelium pellets on aerobic sludge granulation were investigated respectively.The results showed that the addition of 50g of hyphae particles was more favorable for the formation of aerobic sludge particles.Taking the conventional SBAR reactor and the SBAR reactor with carbon nanotubes as the control system,the technical advantages of the hyphae ball to promote the granulation of aerobic sludge were discussed.The research contents and main achievements are as follows:???The hyphae ball promoted the characteristics of aerobic sludge granulation,and investigated the advantages of adding the hyphae ball to the SBAR reactor to promote the granulation of aerobic sludge.The changes of MLSS,SVI,particle size distribution and SOUR in each reactor were compared.The study showed that the SBAR reactor with mycelium pellets was operated for 12 days,and the aerobic granular sludge with particle diameter greater than 0.2mm accounted for 78.86%of the total volume.Compared with the other two groups,aerobic sludge granulation was successful.The granulation time of aerobic sludge was shortened by 5d and 2d respectively.In the stable period of aerobic granular sludge,MLSS and SVI were4090mg·L^-11 and 58.68mL·g^-1,respectively,and SOUR was 49.17O₂/?gMLVSS·h?.???Study on the mechanism of mycelium pellets promoting aerobic sludge granulation,to clarify the mechanism of mycelium pellets promoting aerobic sludge granulation.The relationship between the morphological changes of aerobic granular sludge,the content of EPS components,and the hydrophobicity of PN on the cell surface of each reactor was compared.The results showed that the aerobic granular sludge colloidal aggregates formed in SBAR reactor with mycelium pellets had a high degree of aggregation and little surrounding flocculation adhesion,and the color was yellowish brown;Scanning electron microscopy showed that the appearance of aerobic granular sludge was regular,and the surface was rich in flora structure,The bacilli and cocci were arranged in a staggered manner;At the initial stage of reactor start-up,mycelium pellets could secrete more EPS,and EPS content was always higher than other reactors;PN/PS increased from 0.22 to 0.88,which was conducive to the expression of hydrophobicity on the cell surface,and the correlation between PN and hydrophobicity on the cell surface reached 96.93%.???Study on the stability of aerobic granular sludge promoted by mycelium pellets,to evaluate the long-term operation stability of aerobic sludge granulation system promoted by mycelium pellets.By comparing the integrity coefficient,microstructure and pollutant removal ability of aerobic granular sludge in each reactor.The results showed that the integrity coefficient of aerobic sludge in SBAR reactor with mycelium pellets was always higher than that in other reactors,and the integrity coefficient of aerobic sludge particles after maturity was more than 75%.The structure of granular sludge was compact and stable,and the reactor ran steadily for 116d;When COD and NH₄⁺-N in inlet water increased to 1500mg·L^-11 and 75mg·L^-1,the effluent quality of conventional SBAR reactor deteriorated rapidly,the removal rate of pollutants decreased,and the system became seriously unstable;The removal rates of COD and NH₄⁺-N in SBAR wastewater by adding carbon nanotubes respectively were 90%and80%.The SBAR reactor with the addition of mycelial spheres has strong impact load resistance,and the COD and NH₄⁺-N removal rates are always maintained at around95%and 85%,and the pollutant removal efficiency is high.