Emerging contaminant removal by biofiltration: Temperature, concentration, and EBCT impacts

Abstract

This extensive study investigated the ability of rapid biofiltration to remove selected pharmaceuticals and endocrine-disrupting compounds. Two parallel biofilters with different empty bed contact times (EBCTs) treated municipally and agriculturally impacted river water with wide annual temperature variation. Following acclimation, the biofilters were spiked continuously for slightly more than a year with the selected compounds at alternating low (500 ng/L) and high (5,000 ng/L) levels. Carbamazepine and atrazine were refractory to biodegradation, whereas removals of N,N-diethyl-meta-toluamide (DEET), naproxen, and ibuprofen increased in the order listed. Pseudo-firstorder rate constants were estimated, and values for intermediate temperatures showed some influence of the direction of the seasonal temperature trend, indicating that in real systems there is not a unique relationship between temperature and removal rate. Differences in rate constants reported here and those reported previously by others indicate that biodegradation rates are likely site-specific, underscoring the need for further work. 2015