Study On Formation Of Aerobic Granular Sludge In Sequencing Batch Biofilter Granular Reactor(SBBGR) And Treatment Of Recycled Fiber Paper Wastewater

Aerobic granular sludge technology was a research hotspot in wastewater biological treatment,especially in the treatment of industrial wastewater,because of its high microbial concentration and microbial diversity,strong performance on sedimentation,shock load resistance and simultaneous nitrification and denitrification.However,there are some issues troubling the cultivation of aerobic granular sludge in traditional reactors,such as large excess sludge production and long start-up time,which limited its industrial application.Therefore,this paper studies the application of sequencing batch biofilm granular reactor(SBBGR)technology to the rapid development of aerobic granular sludge and the treatment of on recycled fiber paper wastewater.An SBBGR was operated for about 90 days with the sludge granulation being completed within 50 days.The biomass concentration of granular sludge increased from 5.82 g/L to 42.56 g/L,and the particle size of more than 75%of the granular sludge ranged 1.0-5.0mm.Chemical oxygen demand(COD),total nitrogen(TN)and total phosphorus(TP)of reactor effluent were maintained below 60 mg/L,10 mg/Land1.5 mg/L respectively,with the removal efficiencies reaching 94%,85%and 85%respectively.The mature aerobic granular sludge exhibited dense structure,with massive folds and small pores on the ellipsoidal surface.The abundance and diversity index of microorganisms increased greatly.SBBGR and sequencing batch biofilm reactor(SBBR)were used to treatment the effluent of recycled fiber paper wastewater after coagulation and sedimentation.With influent COD being 5431.9 mg/L,the influent organic load was about 8.1 kg/(m~3·d),the effluent COD of SBBGR and SBBR were 525.3 mg/L and 830.58 mg/L respectively,the removal rates were 90.3%and 84.7%respectively,of TN were 81.9%and 72.8%respectively,of TP were 85.2%and 79.2%respectively,of SS(Suspended Solids)were 73.1%and 78.7%respectively,and of color were 75.1%and 66.7%respectively.FTIR,UV and GC-MS indicated that both reactors were capable of degrading refractory organics such as aromatic compounds.The microbial abundance and diversity of SBBGR biomass were higher than that of SBBR,and more organic compounds could be degraded.SBBGR was applied to the advanced treatment of secondary effluent from paper mill.With influent organic load being 0.66 kg/(m~3·d),effluent COD was 95.32 mg/L,average COD removal efficiency reached 48.63%,effluent SS was 45 mg/L,SS removal efficiency was higher than 80%.The absorption intensity of aromatic compounds,aldehydes,alcohols and phenols of SBBGR effluent was reduced as compared to the influent.UV spectrum analysis showed that SBBGR treatment could promote the degradation of aromatic compounds in wastewater.GC-MS analysis showed that main organic pollutants in wastewater were aromatic compounds derived from lignin and its derivatives,and SBBGR exhibited significant degradation and transformation ability toward them.After the treatment,the biomass in the reactor decreased in quantity,but the microbial diversity increased.The microorganisms that can degrade lignin and its derivative compounds in wastewater became the dominant species.