| Co-Investigator(Kenkyū-buntansha) |
MAEDA Takeki Iwate University, Dept. of Environmental Sciences Associate Professor, 農学部, 助手 (40333760)
SATTA Naoya Iwate University, Dept. of Environmental Sciences Associate Professor, 農学部, 助教授 (20196207)
NISHIYAMA Yoshio Iwate University, Dept. of Environmental Sciences Professor, 農学部, 教授 (90003764)
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| Budget Amount *help |
¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Research Abstract |
In this study, the feasibility to concentrate L-ascorbic acid (Vitamin C, AsA) from wastewater coming from the immersion process at a potato processing plant by electrodialysis was evaluated. It was found that dissolved AsA could be concentrated electrically, by use of electrodialysis. The characteristics of the raw wastewater, the filtrated solution, and the electrodialyzed solutions were also assessed quantitatively. In the diluted solution after electrodialysis, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total solids (TS) and volatile solids (VS) were reduced by 71.0%, 73.7%, 81.0% and 75.2%, respectively, compared to the raw wastewater. In this study, variation of dissolved AsA concentration in the concentrated solution during electrodialysis under several current densities was analyzed using a mathematical model. The calculated values by the model fit the measured values well.
Next, electrodialysis separation of electrolytes (NO_3^-, PO_4^<3->, SO_4^<2->, NH_4^+
… More
, Na^+, K^+, Ca^<2+> and Mg^<2+>) in a drainage nutrient solution from a greenhouse was carried out using two types of ion-exchange membranes. The influences of the ion-exchange membranes as well as the pH of the drainage nutrient solution on the separation performances of the electrolytes were also investigated. The experimental results indicated that ion-exchange membranes for deacidification (AC-220) separated both monovalent and divalent ions from the drainage nutrient solution, while, ion-exchange membranes for desalination (AC-110) indicated monovalent ion selectivity. Regarding the relative energies and current efficiencies, the ion-exchange membranes for deacidification AC-220 indicated better results than for those of the AC-110 membranes for desalination. The separation performances were not significantly influenced by the pH of the drainage nutrient solution for either of the ion-exchange membranes.
Although, the data presented here may not be sufficient to recycle the wastewater, the understanding of separation performances discussed will act as a feasibility study. Less
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