Evaluation of antibiotics, antimicrobial resistance genes and pathogens removal in a decentralized wastewater treatment

Abstract

A decentralized wastewater treatment system is an attractive alternative in small communities, agricultural areas or developing residential areas where investing in sewerage to connect to a centralized plant is not technologically or economically feasible. However, the current technologies applied to the segregated wastewater - black and grey water - remains at the primary treatment level. Furthermore, this wastewater is the major source of groundwater contamination, which is a serious concern for the public health. Therefore, we propose implementing a novel anaerobic-aerobic onsite treatment system in such areas under controlled safety conditions for reuse. The system will comprise an upflow anaerobic sludge blanket (UASB) and an anoxic/aerobic moving-bed bioreactor (MBBR) for organic matter and total nitrogen removal, respectively. Additionally, the presence of emerging contaminants in domestic wastewater, including organic micropollutants such as antibiotics, antimicrobial resistant genes (ARGs), and pathogens, poses a threat to public health. As such, the evaluation of treatment strategies has gained global importance. Moreover, the fate of these contaminants is particularly concerning at the primary treatment level of segregated wastewater. Improving wastewater treatment technology and preventing the misuse of antibiotics are crucial to overcome the threat of ARGs proliferation. Redox conditions, hydraulic retention time, and sludge retention time have been recently explored as key factors in removing contaminants of emerging concern (CECs). However, the mechanisms and pathways behind their removal remain unclear. Therefore, this project aims to assess the fate and occurrence of some target CECs removal in the combined anaerobic-aerobic system. This will create new opportunities for an environmentally and economically sustainable technology for decentralized wastewater treatment plants. Furthermore, this internship project will supplement the ongoing doctoral research by enhancing the researcher's knowledge in the field of domestic wastewater treatment.