Contaminants of Emerging Concern: What Municipalities Need to Know

Contaminants of emerging concern (CECs) are a broad group of substances — pharmaceuticals, personal-care products, hormones, pesticides and industrial chemicals — increasingly detected in water at trace concentrations. They are 'emerging' not because they are new, but because improved analytics now reveal them, and because evidence of their ecological impact is growing.

Standard secondary treatment is designed to remove organic load and solids, not trace synthetic compounds. Many CECs pass through largely untouched, and chlorination can actually create new, sometimes more harmful, by-products. The result is effluent that meets traditional metrics yet still carries a load of micro-pollutants downstream.

Advanced oxidation processes generate highly reactive species that break down complex molecules into simpler, less harmful compounds. Used as a polishing or disinfection step, a powerful oxidiser can destroy CECs that conventional treatment leaves behind — a capability that is becoming essential as discharge and reuse standards tighten.