Study On Rapid Culture And Characteristics Of Aerobic Granular Sludge For Tomato Paste Processing Wastewater

For the processing of Xinjiang agricultural and sideline products(such as tomato sauce,sugar,jam,etc.),the characteristics of seasonal waste water,short production cycle,large emissions,and good biodegradability,aerobic granular sludge technology was adopted to treat tomato paste processing wastewater.The cultivation period of AGS is usually more than 30 days,this long start-up process is not conducive to the popularization and application of the technology.Many studies have shown that microbes had a catalytic effect on granulation during the formation of AGS.The diagnosis of biological phase in traditional activated sludge has been relatively mature,and AGS has more abundant and complex micro-ecological systems to be studied.Based on the above issues,the paper focused on the rapid culture of AGS and the study of microbial community diversity.In view of the important role of EPS in the formation of biological aggregates,the relevant mechanism of AGS process from the perspective of EPS was discussed.The analysis was carried out to provide technical support for the quick culture of AGS.A sequencing batch reactor(SBR)was operated to investigate the effect of clay augmentation on aerobic granulation,flocculent sludge and clay were fed with synthetic tomato paste processing wastewater in the SBR.The combined bio-analytical techniques of scanning electron microscopy(SEM),confocal laser scanning microscopy(CLSM)and live/dead staining were used to characterize the granulation process of activated sludge.The results suggested that the average particle size of the AGS in the reactor adding clay was about 0.54 mm in 20 days.After granular sludge matured,it had good physicochemical properties and decontamination properties,the average removal rate of COD,NH₄⁺-N,PO₄^3--P reached 90%,85%and 40%,respectively.The SEM showed that the granules had a clear outline and a compacting structure.The CLSM revealed that?-D-glucopyranose polysaccharide,?-D-glucopyranose polysaccharide,and protein were widely distributed throughout the whole granule at the same time.Live/dead bacteria staining images of the clay-added granular sludge showed a higher accumulation of dead bacteria and it was encased by live bacteria on the outer layer.In the first round of experiments,microorganisms were used as the research object in the process of granulation of common activated sludge and clay-added sludge.The microbial community structure and the species diversity of microbial communities were investigated during the reactor operation process.High-throughput sequencing results showed that the microbial diversity increased after the addition of clay,Shannon index increased from 4.50 to 4.79.The relative abundance of the Proteobacteria and Bacteroidetes were 63.63%and 30.09%,respectively.The relative abundance of the Zoogloea and Flavobacterium were37.87%and 8.79%,respectively.The study demonstrated that clay could accelerate the formation of AGS,and the effect of maintaining the stability of the system and degrading organic mainly came from the combined action of microbial communities.