Role of biofilms in improving microbial quality in rainwater tanks

Abstract

To evaluate the role of biofilms in improving microbial quality in rainwater tanks, the cell number of Pseudomonas aeruginosa was investigated after inoculation in pilot and full-scale rainwater tanks with different surface-to-volume (S/V) ratios. In pilot-scale experiments, the total number of inoculated cells sampled from the tank water, bottom and walls decreased. After 4 and 5 d, 99% of the inoculated cells were removed from the water in pilot tanks 2 and 1, respectively. Cell death due to low-nutrient conditions contributed to the observed cell number decline. The high removal rate in pilot tank 2 was because of the high S/V ratio. Further, the high removal rate of planktonic P. aeruginosa in full-scale experiment was confirmed in the tanks with high S/V ratios. Our observations indicated that biofilms play a significant role in improving the quality of stored rainwater.

Keywords:

• Biofilms
• Microbial quality
• P. aeruginosa
• Rainwater tank
• S/V ratio

Acknowledgement

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No.0415-20110098).