RESUMEN
Pharmaceutical and personal care products (PPCPs) discharged with wastewater treatment effluents are a surface water quality concern. PPCPs are partially removed during wastewater treatment and biological transformation is an important removal mechanism. To investigate the potential for enhanced PPCP removal using bioaugmentation, bacteria were previously isolated from activated sludge capable of degrading PPCPs to ng/L concentrations. This study examined the degradation kinetics of triclosan and bisphenol A by five of these bacteria, both in pure culture and when augmented to activated sludge. Sorption coefficients were determined to account for the influence of partitioning during bioremoval. When the bacteria were added to activated sludge, degradation increased. Experimentally determined kinetic parameters were used to model a full-scale continuous treatment process, showing that low biomass could achieve reduced effluent PPCP concentrations. These results demonstrated that bioaugmentation may improve PPCP removal using established wastewater infrastructure under conditions of high solids partitioning.
Asunto(s)
Cosméticos/metabolismo , Modelos Biológicos , Preparaciones Farmacéuticas/metabolismo , Sphingomonas/metabolismo , Aguas Residuales/química , Contaminantes Químicos del Agua/metabolismo , Purificación del Agua/métodos , Análisis de Varianza , Compuestos de Bencidrilo/metabolismo , Biodegradación Ambiental , Cromatografía Líquida de Alta Presión , Cosméticos/análisis , Cinética , Preparaciones Farmacéuticas/análisis , Fenoles/metabolismo , Análisis de Regresión , Aguas del Alcantarillado/microbiología , Espectrometría de Masas en Tándem , Triclosán/metabolismo , Contaminantes Químicos del Agua/análisisRESUMEN
Pharmaceutical and personal care products (PPCPs) discharged with wastewater treatment plant (WWTP) effluents are an emerging surface water quality concern. Biological transformation has been identified as an important removal mechanism during wastewater treatment. The aim of this research was the identification of bacteria with characteristics for potential bioaugmentation to enhance PPCP removal. We report here the cultivation and characterization of bacteria capable of degrading PPCPs to ng/L concentrations. An isolation approach was developed using serial enrichment in mineral medium containing 1 mg/L of an individual PPCP as the sole organic carbon source available to heterotrophs until the original activated sludge inocula was diluted to ~10(-8) of its initial concentration, followed by colony growth on solid R2A agar. Eleven bacteria were isolated, eight that could remove triclosan, bisphenol A, ibuprofen, or 17ß-estradiol to below 10 ng/L, one that could remove gemfibrozil to below 60 ng/L, and two that could remove triclosan or E2, but not to ng/L concentrations. Most bacterial isolates degraded contaminants during early growth when grown utilizing rich carbon sources and were only able to degrade the PPCPs on which they were isolated. Seven of the bacterial isolates were sphingomonads, including all the triclosan and bisphenol A degraders and the ibuprofen degrader. The study results indicate that the isolated bacteria may have a positive influence on removal in WWTPs if present at sufficient concentrations and may be useful for bioaugmentation.