Study on denitrification with coffee pectin hydrolysate as carbon source

Abstract

Coffee pectin hydrolysate as an additional carbon source, the denitrification performance was explored by analyzing the denitrification effect in denitrifying biofilter(DNBF) reactor under different HRT and m(COD)/m(TN) (C/N) and microbial community characteristics, and compared with the traditional carbon source of sodium acetate. The results showed that the optimal HRT for the coffee pectin hydrolysate system was 1 h, and the optimal C/N was 6. Under these conditions, when the influent TN and NH4+-N were (33.97±2.06) mg/L and (3.09±0.19) mg/L respectively, coffee pectin hydrolysate as carbon source could reduce the effluent TN and NH4+-N to (3.12±0.59) mg/L and(2.19±0.14) mg/L, respectively. The effluent NO3--N was stabilized below 1 mg/L, and the removal rate reached 97.13%. NO2--N had no obvious accumulation. The NO3--N removed by denitrification per unit COD was 0.22 g/g, which was close to that of the control group sodium acetate. The microbial diversity in the system of coffee pectin hydrolysate was better than that of sodium acetate. There were a large quantities of microorganisms with organic degradation function and denitrification function, such as Zoogloea, Ignavibacterium, unclassified_prolixibacitraceae and Longilinea, which ensured the denitrification effect of coffee pectin hydrolysate as a carbon source.

Keywords

• denitrification
• carbon source
• biological denitrification
• coffee pectin