Pre-electrochemical treatment combined with fixed bed biofilm reactor for pyridine wastewater treatment: From performance to microbial community analysis

To overcome the high biotoxicity and poor biodegradability of pyridine and its derivatives, a pre-electrochemical treatment combined with fixed bed biofilm reactor (EC-FBBR) was designed for multi-component stream cluding pyridine (Pyr), 3-cyanopyridine (3-CNPyr), and 3-chloropyridine (3-ClPyr). The EC-FBBR system could simultaneously degrade these pollutants with a mineralization efficiency of 90%, especially for the persistent ClPyr. Specifically, the EC could partially degrade all pollutants, and allow them to be completely destructed FBBR. With EC off, Rhodococcus (35.5%) became the most abundant genus in biofilm, probably due to its tolerance to 3-ClPyr. With EC on, 3-ClPyr was reduced to an acceptable level, thus Paracoccus (21.1%) competed among interspecies competition with Rhodococcus and became the dominant genus. Paracoccus considered to participate in the subsequent degradation for the residual 3-ClPyr, and led to the complete struction for all pollutants. This study proposed promising combination for effective treatment of multi-component pyridine wastewater.

Automated summary

A method combining pre-electrochemical treatment with fixed bed biofilm reactor was designed to effectively degrade multi-component pyridine wastewater, achieving high mineralization efficiency especially for the persistent 3-chloropyridine. During the treatment process, interspecies competition between Rhodococcus and Paracoccus in the biofilm occurred, with Paracoccus eventually becoming the dominant genus to complete the degradation of all pollutants.