Toxicity of Titanium Dioxide Nanoparticles on Growth Kinetics of Activated Biomass

P. Das, N. Bagdiya, A. Kumar
IIT Delhi, IN

Keywords: bacteria, titanium dioxide nanoparticles, toxicity, wastewater

Summary:

The objective of this study was to study the effect of titanium dioxide (TiO2) NPs on growth kinetic parameters of aerobic sludge bacteria. TiO2 NPs (2 mg/L and 20 mg/L concentrations) were exposed to activated biomass, obtained from a wastewater treatment plant (WWTP) in New Delhi (India) during semi-batch kinetic studies (exposure conditions: mixed-liquor suspended solids: 2000 mg/L; temp.: 36-37°C; pH 7-7.4; exposure duration: 7 days). Results showed that high NP concentration was found to impart more toxicity to bacteria than lower NP concentration for all observation periods. The effect of NP concentration on culturability of bacteria was also observed during plating of samples. These findings indicated that the TiO2 NPs posed maximum threat to bacteria during their stationary phase of growth which might affect the flocculation process of sludge bacteria during biological wastewater treatment.