Long term effect of tetracycline on the enhanced biological phosphorus removal system
Date of Issue2017-05-22
School of Civil and Environmental Engineering
The impact of prolonged exposure to μg/L and mg/L level Tetracycline on the performance of enhanced biological phosphorus removal system and sludge viability and characteristics was investigated in this study. At trace level, Tetracycline’s impact on phosphorus removal and sludge viability was very small. It did result in larger particle size and relatively better settling ability. When higher concentration of Tetracycline was introduced, sludge without prior exposure experienced greatest drop in phosphate removal efficiency from 89.74 % to 33.27%. Both phosphate release and uptake of PAOs were inhibited by antibiotics, especially the phosphate uptake in aerobic stage. Yet microbes could recover from that in the long run at current antibiotics level. The impact on bacterial viability as indicated by MLVSS was small. However, in Live/Dead Cell Staining photographs, sludge with prior exposure showed smaller presence of dead cells. Prior exposed sludge exhibited weak advantage in retaining viability in response to higher antibiotics concentration. Tetracycline’s removal efficiency, mainly proven to be correlated with biodegradation, decreased significantly at higher level. Sludge with prior exposure performed better in this parameter at higher level. Sludge with prior exposure also had average mean particle size decreased from 491.8907 um to 370.0765 um and average SVI value increased from 81.61mL/g to 114.05 mL/g at higher concentration. The reactor without prior exposure showed great increase in average mean particle size from 291.9697 um to 645.042 um as well as SVI value increment from 93.68 mL/g to 122.50 mL/g.
Final Year Project (FYP)
Nanyang Technological University