[Effects of Temperature on the Characteristics of Nitrogen and Phosphorus Removal and Microbial Community in SCSC-S/Fe].

In order to investigate the effect of temperature on the cellulose-degrading bacteria and denitrifying bacteria, the denitrification and phosphorus removal of solid carbon source of cellulose corncob+sulfur/sponge iron nitrogen and phosphorus removal composite system, abbreviated as SCSC-S/Fe, was analyzed under different temperature conditions, and the surface structure and microbial properties of corncob before and after reaction were analyzed by scanning electron microscope (SEM) and MiSeq high-throughput sequencing technologies. The results indicated that when temperature increased from 15, 20, 25 to 30℃, the average TN removal rate of the system increased from 78.88% to 92.70%, the average removal rate of TP increased from 82.58% to 89.15%;microbial properties showed that the surface reaction after corncob was dominated by spherical and rod-shaped microorganisms; the proportion of cellulose-degrading bacteria was 11.01% higher at 30℃ than 20℃, and the proportion of denitrifying bacteria decreased by 21.26%. It can be seen that the cellulose -degrading bacteria were more sensitive to the temperature than the denitrification bacteria, and more obviously affected by the temperature.

[Phosphorus Removal Mechanism of Sulfur/Sponge Iron Composite Fillers Based on Denitrification].

In order to improve the phosphorus removal effect in the denitrification and phosphorus synchronous removal process by sulfur/sponge iron composite fillers, the phosphorus removal effect by different fillers with the coupling microorganisms was studied to analyze the denitrifying phosphorus removal mechanism of the microbial coupling sulfur/sponge iron composite fillers. The research result showed that the phosphorus removal ratio of sponge iron/sulfur composite fillers was over 95%, which was increased by 30% as compared to only sponge iron filler. In addition, the effluent TP concentration was reduced to less than 0.1 mg·L-1. The analysis of X-ray diffraction(XRD)and total iron concentration indicated that the main phosphorus removal system products which were produced in the corrosion and phosphorus removal process of sponge iron were FeOOH, FeS and Fe4 (PO4)3 (OH)3 deposits and dissolved iron ions; FeS and FeOOH which were the hydrolysis products of Fe2+ and Fe3+ converted PO43- to Fe4(PO4)3(OH)3 by adsorption and deposition so that phosphorus removal could be achieved. After the reactor of microbial coupling sulfur/sponge iron carbon composite fillers became stable, the removal efficiency of TN and TP could reach 90% and more than 83%, respectively; Corrosion of sponge iron and phosphorus removal process could also be promoted by biological iron and H+ that was produced in the sulfur autotrophic denitrification process, the system could realize the combination of "heterotrophic synergy autotrophic" composite denitrification and chemical phosphorus removal, and efficient denitrifying denitrification synchronous phosphorus removal process could be achieved in the urban sewage treatment plant.