Enhanced biodegradation of pyridine using sequencing batch biofilm reactor under intermittent micro-aerobic condition

ABSTRACT

A sequencing batch biofilm reactor under intermittent micro-aerobic or anaerobic conditions was investigated to remove pyridine at various concentrations from synthetic wastewater. The results showed that over 98% of pyridine (influent concentration ≤200 mg L⁻¹) was degraded under intermittent micro-aerobic condition, while about 21% of pyridine was removed under anaerobic condition. Additionally, at least 60% of nitrogen located in the pyridine ring was transformed to ammonium. At the same time, the sulphate reduction was obviously inhibited under intermittent micro-aerobic conditions. The microscopic observation showed that abundant microorganisms were attached on the surface or inside of porous biocarriers under intermittent micro-aerobic conditions after a short-term period of operation. High-throughput sequencing analysis demonstrated that Azotobacter, Rhodobacteraceae and Tolumonas were the dominant species in the intermittent micro-aerobic system. The kinetic study at steady period showed that pyridine degradation was fitted well with the pseudo-first-order model (R² > 0.96). The two possible intermediate products were identified and the possible biodegradation pathway of pyridine was proposed under micro-aerobic condition.

GRAPHICAL ABSTRACT

KEYWORDS:

• Pyridine
• intermittent micro-aerobic condition
• sequencing batch biofilm reactor (SBBR)
• kinetic study
• biodegradation pathway

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Junfeng Wan http://orcid.org/0000-0002-0574-5867

Additional information

Funding

The authors thank the National Natural Science Foundation of China [grant number 21107100], Henan Provincial Science and Technology Development Program [grant number 172102410031], Program of Processing and Efficient Utilization of Biomass Resources of Henan Center for outstanding Overseas Scientists [grant number GZS2018004] and Outstanding Young Talent Research Fund of Zhengzhou University [grant number 1421324067] for the financial support of this study.