Cong wins CAPPES Founding President Best Paper Award
Human urine accounts for approximately 1% of domestic wastewater by volume, yet urine contributes a disproportionate mass load to wastewater—greater than 80% of N, 50% of P, and 60% of pharmaceuticals. As such, the destruction of pharmaceutical excreted in urine can be not only beneficial and complementary to current drive for nutrients recovery in source-separated urine, but also an efficient approach to minimize the environmental pollution of these compounds in wastewater, surface water, and drinking water.
Unlike the strong scavenging effects of chloride, ammonium and bicarbonate in synthetic hydrolyzed urine (SHU) on ●OH and SO4●--based AOPs and ozonation from previous studies, Fe(VI) application in degrading pharmaceuticals in SHU was proposed and found to show a mild inhibitory effect from chloride, and enhancement effect from ammonium (when [Fe(VI)]:[ammonium] ratio is higher than 1:167) and bicarbonate. Moreover, this paper is among the first to identify and analyze the enhanced effect of bicarbonate on Fe(VI) oxidation of
sulfonamides (SA). The stoichiometry study between Fe(VI), ABTS, and ABTS●+ revealed distinctively different reactivities between bicarbonate-complexed Fe(V) and phosphate-complexed Fe(V), which sheds light on active iron intermediate species (Fe(V)) using bicarbonate to achieve unexpected enhanced oxidation rate. In-depth investigation indicated that bicarbonate not only changed the Fe(VI):SA complexation ratio from 1:2 to 1:1, but provided stabilizing effect for Fe(V) intermediate formed in situ, enabling its degradation of SAs.
Overall, the effective destruction of pharmaceuticals in urine at the source using Fe(VI) could be an attractive option to minimize energy-intensive treatment required at centralized wastewater facilities to remove these micropollutants, and reduce their potential ecological harm in environmental waters and drinking water. Moreover, the results of this paper provided feasible and effective technology that allows combining resource recovery and destruction of contaminants of emerging concern holistically. The knowledge gained not only can help contaminant cleanup in urine but also is useful across many fields involving various waste streams.
Source: Chinese-American Professors in Environmental Engineering and Science (CAPEES)