Fate of 15 wastewater originated organic micropollutants in a sand column

The present investigation was on the assessment of the fate of 15 organic micro-pollutants (OMPs) under abiotic (predominantly adsorption) and biotic (predominantly bio-sorption/bio-degradation) conditions in columns packed with the aquifer material. The motivation behind this work was to predict the fate of the OMPs during subsurface flow/riverbank filtration (RBF). Columns were packed with aquifer material that was taken out from the laterals of a RBF well, M-15 during its cleaning operation. OMPs that were selected for the study were frequently detected in the river Yamuna, M-15 and other nearby RBF wells. The list included pharmaceuticals and their raw materials, endocrine disruptors, OMPs found in hospital wastes, steroid and personal care products structurally belonging to acrylates, neutral organics, amines, phenols and fatty acids. Among different OMPs, dimethyl maleate, benzoic acid, guanine and lomustine were found to be more mobile than estriol, decanoic acid, 1-tridecanol, 1- eicosanol, triclosan, stearic acid and cetyl alcohol. The mobility depended on the polarity of the OMPs. The retardation factor of non-polar OMPs was more than the polar ones. However, the mobility of the OMPs was considerably restricted in the biotic column. Retardation factors (R_d) for OMPs varied widely in adsorption column from 3 to 772. In biosorption column, R_d ranged from 6 to 1692 showing better removal except for benzophenone. Although, non-polar OMPs may take several years to travel to wells through the sandy aquifer, however, earlier occurrence of some of the polar OMPs cannot be ruled out. Additional treatment for OMPs is must before public distribution.