Advanced treatment technologies for removal of contaminants of emerging concern

Abstract

In the last few decades, pharmaceutical and personal care products, endocrine-disrupting compounds, nanomaterials, and their intermediates have emerged as a new class of environmental contaminants. Collectively these compounds are designated as contaminants of emerging concern (CECs). Concentration of CECs in aquatic systems typically varies from ng/L to μg/L. The presence of CECs even at such low level may render both chronic and acute harmful effects on human health as well as on the ecosystem. The potential adverse health effects associated with these contaminants (CECs) have intrigued development and implementation of a range of technologies for treatment and removal of CECs based on physical, chemical, thermal, and biological methods. Unfortunately, many CECs have poor susceptibility toward the available treatment options. Moreover, technoeconomic feasibility of many of these technologies is limited due to excessive and toxic sludge generation, incomplete removal, high capital and operating costs, and the need for skilled operating and maintenance personnel. For developing effective treatment technologies, it is therefore necessary to understand the mechanisms of various removal technologies and properties of contaminants that influence the removal efficiencies. The objective of this chapter is to summarize the importance, drawbacks, and feasibility of a range of methods that have been used for the remediation of CECs from aqueous systems. This chapter aims to discuss the applications of traditional treatment technologies (physical, chemical, and biological), advanced oxidation processes including membrane filtration, adsorption, electrochemical oxidation, ozonation, Fenton and photo-Fenton processes, catalytic oxidation and photocatalysis, combined processes, and heterogeneous photocatalysis including combined utilization of advanced oxidation processes on mitigation of the CECs from aquatic environment. This chapter also provides a comprehensive assessment of various treatment technologies and their future perspectives for CECs’ removal.