Effects of Fe-C co-substrate environment on iron-based denitrification efficiency and microbial community in wastewater
A co-substrate ferrous denitrification system was constructed and the effects and mechanisms of low-concentration organic carbon(0,3,6,9,12mg/L)on iron-based denitrification under different Fe/N(2,3,4)conditions were investigated by gradient experiments,providing theoretical reference for improving the efficiency of iron-based denitrification.The results showed that the optimal concentration of organic carbon source was 9mg/L in this experiment.When Fe/N=3 and 4,the denitrification efficiency increased by 22.7％and 9.1％respectively compared with that without carbon source,and the promotive effect decreased with the increase of carbon source concentration and Fe/N.The addition of organic carbon had little effect on the diversity and evenness of microbial communities.With the increase of concentration,the total node degree of autotrophic bacteria such as Rhodanobacter and mixotrophic bacteria such as Comamonas and Thauera in the ecological network was always higher than that of heterotrophic denitrifying bacteria.When C/Fe=0.140and 0.187(i.e.,carbon source concentrations of 6mg/L and 9mg/L),the synergistic and symbiotic relationship in the ecological network exceeded 65％,and the carbon source achieved the highest gain effect per unit concentration and the highest denitrification efficiency,respectively.The autotrophic process contributed 39.2％and 56.5％,respectively,to the system denitrification,both of which were dominant.The increase in the abundance of functional genes that dominate NO3-,NO2-,and NO reduction in the system is also an important reason for improving the NO3--N removal efficiency of the iron-based co-substrate denitrification system.
万方数据
维普
