The presence of pharmaceuticals and metabolites in treated wastewater effluents may require additional technologies to prevent probable adverse outcomes upon their discharge into the environment. Wastewater samples were collected from a full-scale wastewater treatment plant with biological nutrient removal. Samples were chlorinated and chloraminated to evaluate the effect of chlorination type, pH, and chlorine concentration. Concentrations of carbamazepine, dihydrohydroxycarbamazepine, epoxycarbamazepine, diclofenac, ibuprofen, naproxen, sulfamethoxazole, and acetylsulfamethoxazole were measured at different time intervals; using 0.35 mM and 2 mM chlorine concentrations. Chlorination was more effective than chloramination for the removal of all micropollutants. When chloramination was conducted at low chlorine concentration, &lt;20% removal was observed for carbamazepine and ibuprofen and an increase in dihydrohydroxycarbamazepine concentration was observed. Nevertheless, chloramination at high concentration resulted in &gt;90% removal in &lt;0.5 hour for some compounds (i.e., carbamazepine, diclofenac and acetylsulfamethoxazole). During chlorination with 0.35 mM chlorine, almost all micropollutants were removed more than 90% in 24h except for ibuprofen which had a removal efficiency of more than 80% in 0.5 hour when chlorine concentration was increased to 2 mM (Figure 1). For some of the metabolites, chlorination significantly increased their concentrations. Increasing the pH to 10 decreased the removal efficiency of most of the compounds during chlorination but did not have a significant effect on the removal of compounds during chloramination. The results suggest that chlorination might be useful for pharmaceutical removal in addition to providing disinfection.

Effect of chlorination and chloramination on the removal of micropollutants in wastewater treatment plants

253rd National Meeting (2017)

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