ASSESSING THE CONTRIBUTION OF COAGULATION/UF, PAC/UF, AND UF/GAC COMBINED PROCESSES TO THE ELIMINATION OF EMERGING CONTAMINANTS.

The elimination of 11 selected emerging contaminants (acetaminophen, metoprolol, caffeine, antipyrine, sulfamethoxazole, flumequine, ketorolac, atrazine, isoproturon, 2-hydroxybiphenyl and diclofenac) has been investigated by means of ultrafiltration membranes in a cross-flow equipment that operated in continuous regime. Two different aqueous systems were used for dissolving the selected pollutants: ultrapure water and a secondary effluent generated in a municipal wastewater treatment plant. The influence of the MWCO of the membranes, and the nature of the water matrix on the permeate flux was established, and the rejection coefficients of the selected compounds were determined. Additionally, in the UF of the secondary effluent, rejection coefficients of several quality parameters (turbidity, chemical oxygen demand, total nitrogen and phosphorus, and absorbance at 254 nm) were also evaluated. In order to enhance the efficiency of the single UF process, three different combined processes were also tested: two pre-treatments consisting in coagulation (by using aluminum sulfate) and adsorption (by using powdered active carbon) stages followed by the UP stage; and adsorption post-treatment (by using granular active carbon) that was conducted to the permeate of the UP stage. The improvements in the elimination of the selected compounds and the quality pollutant parameters were established and discussed. [ABSTRACT FROM AUTHOR]