Estimating organic micro-pollutant removal potential of activated carbons using UV absorption and carbon characteristics

Eight commercially available powdered activated carbons (PAC) were examined regarding organic micro-pollutant (OMP) removal efficiencies in wastewater treatment plant (WWTP) effluent. PAC characteristic numbers such as B.E.T. surface, iodine number and nitrobenzene number were checked for their potential to predict the OMP removal of the PAC products. Furthermore, the PAC-induced removal of UV254 (nm) absorption (UVA(254)) in WWTP effluent was determined and also correlated with OMP removal. None of the PAC characteristic numbers can satisfactorily describe OMP removal and accordingly, these characteristics have little informative value on the reduction of OMP concentrations in WWTP effluent. In contrast, UVA(254) removal and OMP removal correlate well for carbamazepine, diclofenac, and several iodinated x-ray contrast media. Also, UVA(254) removal can roughly describe the average OMP removal of all measured OMP, and can accordingly predict PAC performance in OMP removal. We therefore suggest UVA(254) as a handy indicator for the approximation of OMP removal in practical applications where direct OMP concentration quantification is not always available. In continuous operation of large-scale plants, this approach allows for the efficient adjustment of PAC dosing to UVA(254), in order to ensure reliable OMP removal whilst minimizing PAC consumption. (C) 2014 Elsevier Ltd. All rights reserved.