Advanced treatment of microplastics and antibiotic-containing wastewater using integrated modified dissolved air flotation and pulsed cavitation-impinging stream processes

Livestock and poultry breeding wastewater is a major reservoir of antibiotic resistance genes (ARGs) and antibiotics residues, and it is also a potential reservoir of microplastics (MPs). In this work, a novel system consisting of modified dissolved air flotation (MDAF) and self-excited oscillating pulsed cavitation-impinging (SOPC) processes was established to explore the removal performance of ARGs, antibiotics and MPs. Polydimethyldiallyl ammonium chloride (PDAC) showed better performance than cetyltrimethylammonium bromide (CTAB) in MDAF. At a saturation pressure of 0.4 MPa and 0.8 mg/L of PDAC, 88.3% of MPs was removed by MDAF. More than 97% of antibiotics and 100% ARGs were removed during the SOPC treatment, and 99.2% of antibiotics were removed by the combined system. The SOPC can stably generate hydroxyl radicals (•OH) in wide pH ranges without additional chemicals. This study demonstrates that the hybrid system has the potential to be applied for the advanced treatment of wastewater containing ARGs and MPs.