Removal of pharmaceuticals and endocrine disrupting compounds through pilot- and full-scale riverbank filtration

Abstract

Removal of a large suite of pharmaceuticals and endocrine disrupting compounds (EDCs) was measured through both pilot- and full-scale riverbank filtration (RBF) facilities. The pilot-scale RBF effectively reduced low ng/L concentrations of most compounds by greater than 90% following a 36-day experiment. Breakthrough of the conservative tracer occurred after 10 days and reached 90% recovery after 28 days. Only four compounds (diazepam, meprobamate, phenytoin and tris(2-chloroethyl) phosphate (TCEP)) were between 20 and 80% removed, and three compounds (atrazine, carbamazepine, and sulfamethoxazole) were less than 20% removed by the pilot. Removal of compounds through the pilot-scale RBF is consistent with results from two full-scale RBF systems: atrazine, carbamazepine, meprobamate, phenytoin and sulfamethoxazole persisted through infiltration into drinking water, whereas caffeine, DEET, gemfibrozil, ibuprofen, iopromide, TCEP, triclosan and trimethoprim were removed. Removal during RBF was attributed to (1) microbial degradation for compounds which were either negatively charged or were neutrally charged and had low log KOW values (such as acetaminophen, caffeine, and trimethoprim), or (2) adsorption for neutrally-charged compounds with high log KOW values (including estradiol, estrone, ethynylestradiol, fluoxetine, oxybenzone, progesterone, testosterone, and triclosan).