Effect of Digestate from Methane Fermentation using Ulva sp. and Food Waste for Cultivation of Decolored Pyropia yezoensis (Edible Laver Seaweed)
Effect of Digestate from Methane Fermentation using Ulva sp. and Food Waste for Cultivation of Decolored Pyropia yezoensis (Edible Laver Seaweed)
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DOI：
10.29333/ejosdr/8209
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发表时间：
2020-04
期刊：
影响因子：
--
通讯作者：
K. Kuroda;R. Nishikawa
中科院分区：
文献类型：
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作者：
K. Kuroda;R. Nishikawa
石莼（绿色海藻）经常爆炸性地增殖并在浅水处堆积。这种现象被称为“绿色潮”，是由流入封闭海域的营养物质增加引起的。虽然绿色潮是沿海地区的环境问题之一，但石莼属（Ulva sp.）可以被视为碳中性的，因此可以作为可再生能源的丰富原料。甲烷发酵是将这种海藻转化为能量的合适技术之一。甲烷发酵产生的沼气通常用作肥料;然而，由于城市地区空间有限，它最终被作为废水处理。本文提出了利用混合生物质（石莼和食物垃圾）进行甲烷发酵的厌氧产物可以应用于最近因营养物质减少而出现脱色现象的条斑紫菜（Pyropia yezoensis）的栽培。通过与人工海水的比较，研究了紫菜在实验室条件下对营养物质的吸收和颜色的恢复。结果表明，由于亚硝酸盐的利用，营养物质的吸收和颜色的恢复发生显着，表明其对脱色紫菜的积极影响。此外，实验发现，不仅NH 4-N，而且其他物质如与石莼有关的微量金属也会影响这种效应。研究结果清楚地表明，亚硝酸盐可以在海洋中使用，而且建议的亚硝酸盐的多种用途将增加亚硝酸盐的价值。
Ulva sp. (green seaweed) often proliferates explosively and piles up in shallows. This phenomenon is called “green tide,” caused by increased nutrient flow into an enclosed sea area. Although green tide is one of the environmental problems in coastal areas, Ulva sp. can be regarded as carbon-neutral and therefore can serve as an abundant feedstock for renewable energy. Methane fermentation is one of the suitable techniques for converting such seaweed into energy. Digestate from methane fermentation is normally used as fertilizer; however, it is ends up being treated as wastewater due to limited spaces in urban areas. This paper proposes that the digestate from methane fermentation using mixed biomass (Ulva sp. and food waste) can be applied to the cultivation of Pyropia yezoensis (edible laver seaweed, nori in Japanese), which has recently suffered from decolored phenomena because of decreasing nutrients. The absorption of nutrients and the color recovery of nori were investigated in laboratory-scale experiments based on comparison with artificial seawater. The results highlight that the significant absorption of nutrients and color recovery occurred because of digestate utilization, indicating its positive effects on decolored nori. In addition, the experiments found that not only NH4-N, but also other substances such as trace metal related to Ulva sp. can influence such effects. The findings clearly indicate that digestate can be used in the sea and that the suggested multiple uses of digestate would increase the value of digestate.