Triclosan in biological wastewater treatment: fate, kinetics and population dynamics aspects /

Koç Orhon, Aybala
Biocides like Triclosan (TCS) have been detected in several surface waters due to common usage and following wastewater discharges. This situation necessitates detailed researches on accumulation of these compounds in environment, their effects and removal in treatment systems. In this study, a detailed investigation on biological treatability of TCS bearing wastewaters (100 ng/L-100 mg/L) was conducted. A laboratory-scale activated sludge unit was operated for TCS-acclimated and non-acclimated cultures. Fate of TCS was also studied by constructing mass balances. Possible by-product formation was monitored, as well. It was observed that COD removal declined with increase in TCS, however, COD removals were higher with acclimated cultures than with non-nacclimated ones. Adsorption of TCS onto biomass was evidenced with increased proportions at higher TCS concentrations. 2,4-dichlorophenol and 2,4-dichloroanisole were detected as by-products of TCS biodegradation and acclimation resulted in lower by-product levels. Batch kinetic analysis demonstrated that TCS did not interfere with utilization of biodegradable substrate as long as it was kept below 20 mg/L. Presence of TCS resulted in microbial metabolism to shift from biosynthesis to energy metabolism. Moreover, effect of TCS on microbial population of sludge was searched through molecular biological techniques. In total, 106 microbial species were detected. Although it could not be possible to draw a concrete conclusion and relate them to biokinetic findings due to having too many common species and no information on their dominancy, it was evident that culture compositions vary with acclimation which appears as an important factor for TCS removal, kinetics and by-product formation.
Citation Formats
A. Koç Orhon, “Triclosan in biological wastewater treatment: fate, kinetics and population dynamics aspects /,” M.S. - Master of Science, Middle East Technical University, 2014.