Recycling of biodiesel fuel wastewater for use as a liquid fertilizer for hydroponics
Wastewater is discharged during washing processes in the production of biodiesel fuel (BDF) using alkaline catalysts. It can be recycled as a liquid fertilizer for hydroponics by adding essential components for plant growth. The effects of the liquid fertilizer on plant growth were investigated. Liquid fertilizer containing a smaller amount of the BDF wastewater had a similar effect on plant growth as the standard nutrient solutions. This result reveals that BDF wastewater can be recycled for use as a liquid fertilizer for hydroponics. However, fertilizer with a larger amount of the BDF wastewater showed poor and varied plant growth due to the growth of microorganisms in the contaminated wastewater. Hence, when BDF wastewater becomes contaminated during storage, sterilization is necessary to recycle it as a liquid fertilizer. Moreover, contamination during storage should be avoided for successful recycling.
KeywordsBiodiesel fuel Plant factory Hydroponics Liquid fertilizer Recycling
The authors are grateful to all members of the non-profit organization INE OASA in Kitahiroshima-cho, Hiroshima Prefecture, Japan, for their cooperation. We would like to thank Editage (www.editage.jp) for English language editing. This research was supported by grants from the Satake Technical Foundation and Hiroshima City University Grant for Special Academic Research (General Studies).
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