• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.29-34
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• 2014

This study was conducted to investigate removal characteristics for Synedra sp. and filter run time (FRT) according to the cell length in the Nakdong River. When used alone flocculent, the removal efficiency for Synedra tenera (around $100{\mu}m$) was constant with 90.9~94.4%, while Synedra acus (around $300{\mu}m$) had the lower removal efficiency as 60~70%. $PACS_2$ and PAC showed 5~6% higher removal for S. acus than others (HiB and LAS). When added coagulant aid, loess had no effect and also needed more amount of flocculent. Sodium Silicate increased the removal rate by max 10.6%. On the other hand, 2.5 mg/L of Polyamine showed 96.9% removal efficiency for S. acus increasing up to 25% more than $PACS_2$ alone. In the effect of water temperature, the removal for S. acus at $15^{\circ}C$ were 6% higher than at $4^{\circ}C$. There was no significant correlation between the removal efficiencys of turbidity and S. acus. The results of this study was similar to the actual water treatment process's removal characteristics for Synedra sp. depending on the cell length and temperature. In the actual process, the numbers of Synedra in settled water was established natural logarithm function with the filter run time (FRT), so we can predict FRT as Synedra numbers.