A review of occurrence of emerging contaminants and the advanced analytical techniques used for detection and removal of these pollutants in wastewater

Abstract This chapter focuses on reviewing the literature that provides reliable and quantitative information on emerging contaminants (ECs) in wastewater, focusing on their occurrence, detection and removal efficiency using advanced analytical techniques. In addition, providing knowledge on areas of ECs that are non-regulated since the environmental legislations and policies are being developed. Some of the classes of ECs include pharmaceuticals, nanomaterials, herbicides, personal care products and microplastics and many more. ECs have been identified as an environmental problem globally and are a result of different compounds ranging from inorganic to organic compounds which are released into the environment. ECs are commonly found in aquatic environments and the main source of ECs are municipal wastewater, domestic discharge, hospital effluents, industrial wastewater and agricultural run-off. The presence of ECs poses health problems and ecological impacts associated with them. The elevated concentration of ECs in wastewater has necessitated a need to research their varying detection techniques and different ways of removal. Water contamination by ECs is also attributed to an increase in urbanization, industrialization and agricultural activities. Current wastewater treatment plants are inefficient in the removal of ECs as they were not initially designed for the treatment and removal of ECs, these may result in the transformation of EC products that are undetected and unregulated. These products exhibit similar toxicity as their parental ECs, while some of the ECs have been recognized as endocrine-disrupting chemicals. Due to new ECs being introduced, there is a gap in knowledge of their detection and treatment techniques for their removal, thus demonstrating a need for integrated analytical approaches that compliments the screening and removal of target and non-targeted ECs with biological assays. Development advancement of analytical techniques has enabled the detection, identification and treatment of ECs in trace concentration (mg to ng/L), and the development and advancement of hybrid treatment systems are emerging promising treatment solutions. The use of nanomaterials and phytoremediation approaches are new approaches widely studied as a good potential process for remediating the ECs in wastewater.