Effective removal of chlortetracycline and treatment of simulated sewage by Bacillus cereus LZ01 immobilized on erding medicine residues biochar

Contamination of chlortetracycline (CTC) in water is a global problem that needs to be addressed urgently. Biochar immobilization of microorganisms is an effective way to remove CTC contamination from sewage. In this study, the CTC removal effect of free bacteria LZ01 and erding medicine residues biochar immobilized LZ01 was compared by shake flask batch experiments. The results showed that immobilized LZ01 significantly improved the CTC removal rate by 15.27% compared to free LZ01. The immobilization of LZ01 also significantly improved the environmental tolerance and the reusability and storage stability of strain LZ01. The optimal conditions for CTC removal (83.83%) by immobilized LZ01 were determined by response surface methodology: temperature of 33.98 degrees C, pH of 7.84, initial CTC concentration of 73.75 mg/L, and inoculation dose of 0.51% (w/v). The experimental results of treating CTC from simulated sewage showed that the immobilized LZ01 could remove more than 64% of CTC from the sewage. The ion of Cu2+ accelerated the removal of CTC by immobilized LZ01, and the removal rates could reach 81.07%, 85.07%, and 87.50% in three sewages, i.e., river sewage, pond water, and farming wastewater, respectively. This study provides a feasible, effective, and rapid biological removal technique for the treatment of CTC pollution in sewage.