Removal of Trace Organic Compounds in Domestic Wastewater using Recirculating Packed-Bed Media Filters

Pharmaceuticals and personal care products (PPCPs) are commonly detected in the environment resulting from their survival from conventional wastewater treatment systems. More information is needed about the fate and transfer of these trace organic compounds in domestic wastewater and their associated risks so that efficient strategies for their removal can be developed for both large/small scale treatment systems. This study aimed to determine whether onsite wastewater treatment systems were capable of providing PPCP removal, in addition to quantifying different forms of removal (biodegradation/sorption). A column study was constructed to determine the removal efficiencies of 3 target PPCPs, endocrine disrupting compound triclosan (TRI) and non-steroidal anti-inflammatory drugs ibuprofen (IBU) and naproxen (NAP), in a small-scale recirculating media filter. To ensure bioreactor productivity the pH, chemical oxygen demand (COD), total organic carbon (TOC), and total nitrogen (TN) of the influent and effluent were analyzed. All columns showed consistent neutralization of pH, coupled with a large removal of COD (>90%) and TOC (>95%). Nitrifying/denitrifying conditions were attained, presenting removal of TN between 35% and 85% in all columns. Spiked experimental columns (0.1 ppm) with the target PPCPs were compared to one controlled column. Mean total removal of the trace organics were moderately high (>80%). Sorption of the PPCPs onto biofilm was quantified; TRI experienced the highest sorption (2.5±0.2%), followed by IBU and NAP (0.3±.1 and 0.4±0.3%). Therefore, estimated degradation percentages of parent compounds for IBU, NAP, and TRI were 85±8.2%, 88±4.6%, and 86±2.2%, respectively. Negative mass balances of PPCP removal occurred within experimental columns only, suggesting possible desorption or change in degradation kinetics attributed to compound addition.