Advanced treatment of antibiotic wastewater by ionizing radiation combined with peroxymonosulfate/H2O2 oxidation

The advanced treatment of secondary effluent from an antibiotic wastewater treatment plant was investigated using ionizing radiation alone and combined with peroxymonosulfate (PMS)/H2O2 oxidation. In the effluent, 3 antibiotics, including erythromycin (ERY), tetracycline (TC), sulfamethoxazole (SMX), and 7 groups of antimicrobial resistance genes (ARGs) and 12 bacterial classes were detected. Results showed that the content of antibiotics and ARGs could be reduced greatly by radiation. The removal of ERY, TC and SMX reached 87%, 80% and 48% respectively, while the abatement of ARGs, including ermB, ermT, ermF, maA/mel, sul2, blaOXA, floR and mefA reached 63-91%. The COD removal was only 16.8% at 25 kGy. The enhancement with PMS addition was better than with H2O2 addition during radiation. With 10 mM PMS addition, the removal efficiency of antibiotics and COD increased to 70-98% and 57.6%, compared to 55-97% and 45.1% with 10 mM of H2O2 addition at 25 kGy. The PICRUSt analysis suggested that radiation at a dose of higher than 25 kGy could stimulate the bacterial activity for metabolism of amino acid, carbohydrate and energy, etc, but damage the genes coding for cellular and genetic information processing. The major ecological risk is derived from ERY (high level) and TC (medium level) in the effluent. The ecological risk of ERY and TC could be declined to medium level and low level, respectively after radiation with 10 mM PMS/H2O2 addition at 25 kGy. However, the operating cost of EB/PMS processes was more than twice higher than that of EB/H2O2 processes. Based on the tech-economic evaluation, ionizing radiation combined with H2O2 was a promising technology for the advanced treatment of pharmaceutical wastewater.

Automated summary

The study investigated the advanced treatment of secondary effluent from an antibiotic wastewater treatment plant using ionizing radiation alone and combined with peroxymonosulfate (PMS)/H2O2 oxidation. Results showed that radiation could greatly reduce the content of antibiotics and antimicrobial resistance genes (ARGs), while the addition of PMS was better than H2O2 in enhancing the removal efficiency. Higher doses of radiation stimulated bacterial activity but damaged genes coding for cellular and genetic information processing. The ecological risk mainly came from erythromycin (ERY) and tetracycline (TC), which could be reduced to medium and low levels, respectively, after radiation.