| Biological phosphorus removal granular sludge is a kind of granular sludge with excellent phosphorus removal capacity,which has the advantages of high microbial enrichment,high load resistance and fast settling rate.In this study,four different carbon sources of sodium propionate,sodium acetate,glucose and sucrose were used to configure artificial wastewater to cultivate biological phosphorus removal granular sludge.After 90 days of stable operation of the SBR reactor,the effects of different influent carbon sources on the sludge characteristics and microbial population structure of the biological phosphorus removal granular sludge were investigated.Based on the characteristics of long culture period and high market demand for storage and transportation of granular sludge,sodium propionate biological phosphorus removal granular sludge with the best performance was selected for storage to investigate the best storage conditions for biological phosphorus removal granular sludge.The main research findings are as follows:(1)When the carbon source type is easy to be degraded by microorganisms,the microorganisms metabolize quickly and produce brighter metabolic products,and the granular sludge formed is lighter in color and larger in particle size.When the carbon source was sodium propionate,the particle size of granular sludge was the largest,and the sludge was mainly white granular sludge and coexisted with yellow granular sludge;when the carbon source was sodium acetate,the sludge was mainly yellow granular sludge with a small amount of white granular sludge,and the sludge was full and regular in shape;when the carbon source was glucose and sucrose respectively,the sludge was yellow granular sludge,and the surface of granular sludge was concave and not rounded.(2)The type of carbon source has a greater influence on the effectiveness of biological phosphorus removal granular sludge in removing pollutants from water.Under the conditions of PO43--P,COD,and TN influent concentrations of 22,500,a nd 30 mg/L,respectively,sodium propionate was the best carbon source for remo-vi ng PO43--P and COD,and the removal efficiency could reach 98.5%and 93.3%,a nd the efficiency of removing TN was comparable to the reactor of sodium acet-ate group,and the two groups could reach 71.5%and 73.4%,respectively,and the de nitrification capacity of both groups was higher than that of glucose Both groups ha d higher denitrification capacity than glucose,sucrose and sucrose groups.The re moval ability of sucrose system was the weakest for each pollutant,and the rem-ov al effect of PO43--P,COD and TN was only 45.3%,76.7%and 55.3%.(3)Under certain conditions,the biological phosphorus removal granular sludge can be stored for a long time.The comprehensive settling performance,SOUR,dehydrogenase activity,and pollutant removal effect were compared,and the long-term storage effect was relatively best under the conditions of low temperature and pure water as medium.After resuming operation for 15 days,the removal efficiency can reach 89.8%and 96.1%under the conditions of PO43--P and COD influent concentration of 22 and 450 mg/L,respectively.(4)The influent carbon source had a significant effect on the microbial population structure.The structure of microbial populations in each system was similar at the phylum and order level,but there were large differences at the genus level.The dominant species of phosphorus removal in the sodium propionate system,Accumulibacter,accounted for 30.99%,while Defluviicoccus and Competibacter,belonging to the genus Glycococcus(GAOs),accounted for a larger proportion in the sodium acetate system,with a total of 33.49%.The dominant genus in the glucose system was Defluviicoccus with 11.68%,and the dominant genera in the sucrose system were Amaricoccus and Microbacterium with 17.42%and 17.28%,respectively.(5)The carbon source had a significant screening effect on denitrifying phosphorus-polymerizing bacteria in the biological phosphorus removal granular sludge system.The sodium propionate and sodium acetate systems all contained a high proportion of denitrifying polyphosphorus bacteria,with Pseudomonas spp.with denitrifying effect accounting for 15.60%in the sodium propionate system and Flavobacterium spp.with denitrifying effect accounting for 11.82%in the sodium acetate system.The presence of denitrifying polyphosphorus bacteria was not detected in the dominant genera of glucose and sucrose systems. |
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