Enhanced treatment of pyridine wastewater by a hybrid membrane biofilm reactor: Simultaneous biodegradation of pyridine and removal of nitrogen

To achieve simultaneous and efficient removal of pyridine and nitrogen during pyridine wastewater treatment, a hybrid membrane biofilm reactor (HMBfR) containing a nonaerated zone and a membrane-aerated zone was constructed. The oxygen mass transfer performance of the membrane module in clean water was investigated via oxygenation experiments using air and pure oxygen as the aeration matrices, and then the performance of the HMBfR for treating pyridine wastewater was studied with air and pure oxygen as the aeration matrices. The overall oxygen mass transfer coefficient when using an oxygen matrix was 3.07~4.02 times greater than that when using an air matrix. Compared with the air-HMBfR, the O2-HMBfR enhanced the treatment effect of high-strength pyridine wastewater, and the pyridine removal load per unit membrane area (3.33±0.07 g/m2·d) and total nitrogen removal rate (86.24±0.01%) significantly improved. A sufficient oxygen supply facilitated synergism among microorganisms in different zones and promoted pyridine oxidation and ammonium nitrification in the membrane-aerated zone, while simultaneous pyridine removal and nitrate denitrification were enhanced in the nonaerated zone. The developed HMBfR provides a green, efficient solution for high-strength pyridine wastewater treatment that enables the simultaneous removal of pyridine and total nitrogen in a single reactor.