The efficiency of integrated wastewater treatment plant for pollutant removal from industrial-scale lincomycin production

Abstract Currently, antibiotics are widely used in clinics, graziery, and aquaculture. Antibiotics are prescribed to treat infections by bacteria and parasites; therefore, the industry generates significant quantities of antibiotics. However, a large amount of wastewater also gathers simultaneously, which contains high-level chemical oxygen demand (COD) and nitrogen pollutants that must be reduced to permissible standards before disposal. For this purpose, an industrial scale lincomycin production wastewater treatment plant (WWTP) that employs physicochemical and biological processes for neutralization and subsequent removal of concerning pollutants is built. The WWTP consists of three types of bioreactors, including four hydrolysis acidification bioreactors (HAT), eight anaerobic expanded granular sludge bed (EGSB) bioreactors, and four aeration-oxic bioreactors (AOT). This study has been conducted to evaluate the efficiency of the WWTP. The study data revealed removal of 98.9% of 28922.1 kg/d COD and 98.0% of 1557.8 kg/d NH3-N after treatment of wastewater in WWTP, thus matching the effluent criteria. The HAT, EGSB, AOT and physicochemical treatment accounted for 11.1%, 61.9%, 20.2%, and 6.8% of COD removal, respectively. The AOT bioreactors removed major amounts of NH3-N. The analyses of microbiota showed that diverse microbial species were harboring in the bioreactors, which could treat the toxic bacteria in the wastewater. Moreover, dominant microbes in these three types of bioreactors were significantly different and formed three clusters according to the network analyses. Several keystone species, found in the system, participated in the COD and NH3-N removal process, demonstrating the pollutant removal ability at the species-level. In summary, a lincomycin production WWTP exhibited good performance and efficiency for the pollutant removal. Microbiota and keystone species involved in the pollutant removal process were identified, which would help to discover the mechanism of pollutant removal and to improve the removing ability in future designs.