PVA/WPU/SA凝胶球的制备及其对低温生活污水脱氮性能的影响OA

In order to improve the denitrification performance of activated sludge process at low temper-atures,polyvinyl alcohol(PVA),waterborne polyurethane emulsion(WPU),and sodium alginate(SA)were blended via a heated blending method.Gel beads were subsequently fabricated by chemical crosslinking in a boric acid system to improve nitrogen removal from low-temperature domestic sewage.A comparative investigation was conducted using SBR reactors with in-situ microbial enrichment,evalua-ting three systems:conventional activated sludge system(SBR-R1),commercial K3 carrier-enhanced sys-tem(SBR-R2),and gel bead carrier-enhanced system(SBR-R3)under both ambient temperature(17 to 22℃)and low-temperature conditions(15℃and 12℃).The results show that the pore size distribu-tion of 10%PVA/6%WPU/0.5%SA composite carrier is 10 to 20 μm,and the deformation can be re-stored by 99.908%after 1 mm compression,which has good mass transfer and stability.Under low-tem-perature conditions at 15℃,the total nitrogen(TN)removal efficiencies in the three groups of reactors were 45.79%,52.75%and 62.14%,respectively.The gel bead carrier-enhanced demonstrated superior denitrification performance,exhibiting 2.35-fold greater enhancement efficacy compared to the K3 carrier-enhanced system.Even under the lower-temperature condition of 12℃,SBR-R3 persistently demonstra-ted optimal denitrification performance,achieving a total nitrogen(TN)removal efficiency of 53.83%.Under low-temperature conditions,Proteobacteria,Patescibacteria,and Bacteroidota emerged as the domi-nant bacterial phyla.When the temperature was reduced from 15℃to 12℃,small-celled Patescibacteria and its genus norank_Saccharimonadales exhibited significant enrichment within the gel bead carrier,po-tentially through an avoidance adaptation mechanism.