Phosphine production in anaerobic wastewater treatment under tetracycline antibiotic pressure

The influence of tetracycline (TC) antibiotics on phosphine (PH₃) production in the anaerobic wastewater treatment was studied. A lab-scale anaerobic baffled reactor with three compartments was employed to simulate this process. The reactor was operated in a TC-absence wastewater and 250μg/L TC-presence wastewater for three months after a start-up period, respectively. The responses of pH, oxidation-reduction potential (ORP), chemical oxygen demand (COD), total phosphorus (TP), enzymes activity (dehydrogenase and acid phosphatase), and microbial community were investigated to reveal the effect of TC on PH₃ production. Results suggested that the dehydrogenase (DH) activity, acid phosphatase (ACP) activity and COD have positive relationship with PH₃ production, while pH, ORP level and the TP in liquid phase have negative relationship with PH₃ production. With prolonged TC exposure, decrease in pH and increase in DH activity are beneficial to PH₃ production, while decrease in COD and ACP activity are not the limiting factors for PH₃ production.