• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.270-275
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• 2013

The aim of this study was to investigate the efficiency of thickness of optical panel (OP) on the growth rate of Chlorella vulgaris. The size of Chlorella vulgaris (FC-16) was $3-8{\mu}m$, having round in shape. The cells of Chlorella vulgaris was cultured in the Jaworski's Medium with deionized water at $22^{\circ}C$ for 15 days. For this experiment, three OP samples were prepared to evaluate the efficiency of thickness of OP on the growth rate of Chlorella vulgaris; 4 mm OP with LED (Light Emitting Diode) (Run 1), 6 mm OP with LED (Run 2) and 8 mm with LED (Run 3). The diffuse rate was reached 86%, 91% and 92% for Run 1, Run 2 and Run 3, respectively. Average biomass of Run 2 and Run 3 were measured 11.18% higher than that of Run 1. However, the specific growth rate for all fractions were almost same. In addition, chlorophyll content per cell and cell volume were found to be slice difference between Run 2 and Run 3. Therefore, Run 2 has more effect on growth rate of biomass for Chlorella vulgaris than Run 1 and Run 3.

• Journal of Korean Society on Water Environment
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• v.30 no.4
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• pp.386-393
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• 2014

The aim of this study was to investigate the nutrient removal and biomass productivity in the wastewater using MMBR (Microalgae Membrane Bioreactor). MMBR process was combined OPPBR (Optical Panel Photobioreactor) and MBR (Membrane bioreactor). The OPPBR and MBR were operated 3 days and 9h HRT (Hydraulic retention time), respectively, using microalgae as Chlorella vulgaris. The obtained result indicated that the biomass productivity of 0.498 g/L/d with light transmittance of 92% at a 305 mm depth in the OPPBR was achieved. The total consumption of BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) in the MMBR were found to be 97.56% and 96.06%, respectively. Additionally, the removal of TN, $NO_3-N$, TP and $PO_4-P$ were 94.94%, 91.04%, 99.54% and 93.06% in MMBR, respectively. These results indicated that the MMBR process was highly effective for COD, BOD and nutrient removal when compared to the separate OPPBR or MBR process. The MMBR process was effective for nutrient removal and biomass productivity and can be applied to treat wastewater in sewage treatment plant.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.467-472
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• 2012

The aim of this study was to investigate the efficiency of optical panel (OP) on the growth rate of Chlorella vulgaris (C. vulgaris). The size of C. vulgaris (FC-16) was 3~$8{\mu}m$, having round in shape. The cells of C. vulgaris was cultured in the Jaworski's Medium with deionized water at $22^{\circ}C$ for 15 days. For this experiment, three light samples were prepared to evaluate the efficiency of OP on the growth rate of C. vulgaris; OP with LED (Light Emitting Diode) (Run 1), Fluorescent light (Run 2) and LED (Run 3). The specific growth rate of C. vulgaris for Run 1 was found to be 14 times and 5 times faster than Run 2 and Run 3, respectively. In addition, the average biomass of C. vulgaris for Run 1 was measured 11.79 g/L in 11 days. This means that the biomass for Run 1 was reached 30 times and 6.5 times higher than Run 2 and Run 3, respectively. This may be due to the fact the OP was increased the light uniformity and hindered the shading effects in photobioreactor. Therefore, the growth rate of biomass in photobioreactor with OP is compared better than the without OP used other photobioreactor.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.3
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• pp.214-220
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• 2014

The aim of this study is to optimize the efficiency of a photobiorector on the growth rate of Chlorella vulgaris (C. vulgaris) by varying distance of optical panel (OP). The round shaped C. vulgaris (FC-16) having the size of $3-8{\mu}m$ is employed in this study. The cells of C. vulgaris are cultured in the Jaworski's Medium with deionized water at $22^{\circ}C$ for 15 days. The OP is placed at four different distances i.e., at 225 mm distance (Run 1), 150 mm distance (Run 2), 112.5 mm distance (Run 3) and 90 mm distance (Run 4) having a LED (Light Emitting Diode) source. The diffuse rate is achieved to 86%, 90%, 92% and 94% for Run 1, Run 2 Run 3 and Run 4, respectively. A narrower distance of OP caused to effectively to increase the efficiency of diffuse light rate. For mass cultivation of this biomass, medium is changed according to distance of OP after attaining a maximum biomass concentration; Run 1 in 8 days, Run 2 in 6 days, Run 3 in 4 days and Run 4 in 3 days. In addition, the amount of maximum biomass rate for Run 4 was reached 3 times higher than that of Run1. However, growth rate, chlorophyll per cell, cell volume and doubling time are found to be Run 3 and Run 4 higher than that of Run 1 and Run 2 samples. However, Run 3 and Run 4 are having a slight difference in all these measurements. These findings suggest that in terms of economic consideration and efficiency towards simultaneous mass cultivation of biomass, Run 3 was found to be more effective than other samples.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.134-141
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• 2015

The focus of this study was to observe the growth of Chlorella vulgaris and Botryococcus braunii under mixotrophic conditions (i.e., added acorn) with the aim of increasing biomass and triacylglycerols (TAGs) content. The result of investigation indicated that the acorn contains a lot of carbonate (87.29%) and glucose (97.99 mg%). A significant growth of biomass was obtained when grown in acorn rich environment comparing to autotrophic conditions. 3 g/L acorn yielded the highest biomass concentration for these strains. Thus, the biomass productivity with 3 g/L acorn was obtained 2.31 times and 2.10 times higher than that of authotrophic conditions for Chlorella vulgaris and Botryococcus braunii, respectively. The maximum amount of TAGs was reached 14.35% and 18.41% for Chlorella vulgaris and Botryococcus braunii, respectively, in the growth medium with 5 g/L acorn. The effect of acorn could enhance the investigated microalgae growth, biomass productivity and TAGs content. This provides a feasible way to reduce the cost of bioenergy production from microalgae.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.647-652
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• 2014

The aim of this study was to investigate the heavy metal removal and biomass productivity in the Acid Mine Drainage (AMD) using eggshell and microalgae. The experiment was operated 6 days in the eggshell and microalgae hybrid system, and using eggshell powder and microalgae as Chlorella vulgaris. The obtained result indicated that the biomass productivity of 2.82 g/L/d from 1.12 g/L initial concentration in 6 days was reached with light transmittance of 97% at a 305 mm depth in the optical panel photobioreactor (OPPBR). The total removal efficiency of Fe, Cu, Zn, Mn and Cd was found to be 98.92%, 99.91%, 98.78%, 88.99% and 98.00% in the AMD using eggshell and Chlorella vulgaris hybrid system, respectively. Additionally, there were significant relationships between biomass and concentration of each heavy metal ($R^2$ = 0.8771, 0.8643, 0.8669, 0.9134 and 0.6277 for Fe, Cu, Zn, Mn and Cd). These results indicated that the eggshell and microalgae hybrid system was highly effective for heavy metal removal when compared to the conventional biological process in the AMD. Therefore, the eggshell and microalgae hybrid system was effective for heavy metal removal and biomass productivity and can be applied to treat AMD in treatment plant.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.469-476
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• 2014

The focus of this study was to observe the growth of Chlorella sp., Nannochloris sp., and Botryococcus braunii under mixotrophic conditions (i.e., added glycerol) with the aim of increasing the growth of biomass and algae oil content. A significant growth of biomass was obtained when grown in glycerol rich environment comparing to autotrophic conditions. 5 g/L glycerol yielded the highest biomass concentration for these strains. Mixotrophic conditions improved both the growth of the microalgae and the accumulation of triacylglycerols (TAGs). The maximum amount of TAG in Botryococcus braunii was reached in the growth medium with 10 g/L glycerol and Chlorella sp., Nannochloris sp. with 2 g/L glycerol. The content of saturated fatty acids of Chlorella sp., Nannochloris sp., and Botryococcus braunii was found to be 34.94, 14.23 and 13.39%, and the amount of unsaturated fatty acids was 65.06, 85.78 and 86.61% of total fatty acids, respectively. The fatty acid profiles of the oil for the culture possibility met the necessary requirements and are, therefore, promising resource for biofuel production.