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DOI : ,    Vol.22, No.3, 67 ~ 75, 2014
Title
Trophic State Evaluation and Pretreatment of Lake Water with Fluctuating Runoff from Nonpoint Source
김지연 Ji Yeon Kim , 이형옥 Hyeong Ok Lee , 현길수 Kil Soo Hyun
Abstract
This study was performed to evaluate a trophic state of lake water and the pretreatment characteristics of the lake water with fluctuating runoff from nonpoint source, located at the upper basin of Daecheong Lake. Lab-scale plant used for this study consisted of raw water tank, granular activated carbon (GAC) bed, and treated water storage tank. Applied empty bed contact time (EBCT) and linear velocity (LV) for GAC bed packed to 1m with particle size of 1-3mm were 15 min. and 6. m/d Influent concentration into the lake were 2.1 to 5.0mg/L for COD, 2.054 to 3.159mg/L for T-N, 0.021 to 0.153mg/L for T-P, 1.6 to 12.5mg/m3 for Chl-a and 1.3 to 35.8NTU for turbidity, respectively. Regression analyses of log transformed seasonal Chl-a against T-P and T-N showed that variation of Chl-a was closely related with the variation of T-P(r= 0.224) and T-N(r=0.125) concentrations. The analysis results of Korean trophic state index (TSIko) for the lake water indicated that phosphorus was an influence pollutant on algae growth. The average removal efficiencies of GAC bed for COD, Turbidity, TN and TP were 79.9%, 98.4%, 29.4% and 12.5%, respectively. In particular, GAC bed achieved higher Chl-a removal efficiencies in the range of 75.0 to 95.3%. Compared with powdered activated carbon (PAC) and submerged aeration (SA), the efficient process on Chl-a removal was generally in the order of GAC> PAC> SA.
Key Words
Algae, Lake, Trophic State, Runoff, GAC, PAC, Nonpoint source
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