A biofilm reactor based on slow-release carbon source effectively improved the continuous denitrification capacity of slightly polluted surface water at low carbon to nitrogen ratio

A biofilm reactor was exploited using Burkholderia sp. CF6. Polymers were attached to alkali-modified corn stover (CS) to prepare a novel slow-release carbon source. The slow-release carbon source not only released carbon into the nutrient-poor water in a stable manner to ensure denitrification, but also the microporous structure of the slow-release carbon source promoted the degradation of cellulose. Box-Behnken design was used to study the effects of hydraulic retention time (HRT), pH, and carbon to nitrogen ratio (C/N) on the nitrate removal efficiency. Under the HRT of 4 h, pH of 7.0, and C/N of 1.0, the nitrate removal efficiency reached 98.03%. Three-dimensional excitation emission matrix (3D-EEM) results showed that soluble microbial products (SMP) play a dominant role in denitrification. The PCR amplification technique showed that Burkholderia sp. CF6 assumed the main denitrification role in the reactor. This study provides a theoretical basis for the effective management of micro-polluted water bodies.

Automated summary

A biofilm reactor using Burkholderia sp. CF6 was developed, and polymers were attached to alkali-modified corn stover to create a novel slow-release carbon source. This carbon source released carbon steadily to support denitrification while promoting cellulose degradation. The effects of hydraulic retention time, pH, and carbon to nitrogen ratio on nitrate removal efficiency were studied, and optimal conditions yielded a removal efficiency of 98.03%. Soluble microbial products were found to play a dominant role in denitrification, and Burkholderia sp. CF6 was identified as the main denitrifying agent. This study provides a theoretical basis for effective management of micro-polluted water bodies.