Key Problems and Novel Strategy of Controlling Emerging Trace Organic Contaminants During Municipal Wastewater Reclamation

Abstract

Emerging trace organic contaminants (TOrCs) have been ubiquitously detected in municipal wastewater. TOrCs show low concentrations but are usually harmful to aquatic biota and recalcitrant to treatments. The advanced treatment of TOrCs is challenged by four main aspects. First, it is hard to qualify the chemical structure and concentrations of TOrCs, which are typically very low. Second, risk assessment results vary with the selection of target-species and toxicity-endpoints, which makes it hard to regulate priority lists and concentration limits. Third, TOrCs account for less than 0.01% of the total organics in wastewater. Thus, TOrCs cannot be selectively and efficiently removed by conventional treatments. Fourth, it is hard to optimize and manage the treatment trains of TOrCs. In this manuscript, a new strategy combing non-targeting TOrC screening and TOrC "fingerprinting" are proposed to overcome the difficulties of quantification and treatment optimization. Based on this, the standards and regulations to control the TOrCs in reclaimed water should be developed on the basis of elimination efficiency rather than concentration.