Effect of triclosan on protozoa in wastewater treating bioreactors

摘要

The effect of antimicrobial chemical, triclosan (TCS) on protozoa present in aerobic and anaerobicnbioreactors for wastewater treatment is reported in this study. Bioreactor sludge ciliated protozoansuch as Spirostomum, Cyclidium and Colpoda and flagellated protozoa Mastigella were exposednto TCS at 1 mg/L level in batch cultures. The response of TCS on protozoa was followed bynmicroscopic observation of the sludge at specific time intervals. Among the protozoa in aerobicnsludge, Colpoda exhibited strong sensitivity to triclosan and the cells distorted and burst in 20nminutes period. Mastigella and Spirostomum were resistant to triclosan for first two days, butnafterwards the mobility was found declined and subsequently mortality increased to 100% innfour and five days respectively. Anaerobic sludge ciliate, Cyclidium exhibited morphologicalndistortion and motility decline after 1 hour exposure to triclosan. The sludge flocs werenaffected and pelagic cell count declined by the presence of triclosan at the tested level.