设施园艺废弃物厌氧消化产沼气特性

    Biogas-producing characteristics of anaerobic digestion of protected horticulture residues

    • 摘要: 为获得典型设施园艺废弃物的产沼气特性,该文分析了5种不同设施园艺废弃物-黄瓜蔓、西红柿茎叶、小白菜、西瓜蔓和青草的物料特性,并在中温条件下研究了5种原料的厌氧发酵产气特性;在38℃条件下,以西瓜蔓为例进行了分离式两相厌氧消化工艺(separated two phase anaerobic digestion,STP)回流方式比较试验,比较分析了西瓜蔓在渗滤液喷淋和浸泡2种回流方式下的产气性能,研究了不同回流方式下的渗滤液pH值、沼气产量、甲烷含量的变化,为设施园艺废弃物的资源化利用提供了有益的参考。试验结果表明:5种设施园艺废弃物的产气潜力由大到小依次为西瓜蔓、小白菜、黄瓜蔓、西红柿茎叶和青草,其中西瓜蔓的单位干物质产气量达到508.85 mL/g(干物质total solid,TS);设施园艺废弃物对分离式两相厌氧消化工艺(STP)具有良好的适应性,渗滤液喷淋回流方式要优于浸泡回流方式,其产气量和甲烷含量更高,其中累计产气量达到506.39 L,比浸泡回流方式高出10.81%,甲烷体积分数基本稳定在53%~56%,系统稳定性更好,研究结果为设施园艺废弃物的处理与利用提供参考。

       

      Abstract: Abstract: With the large-scale popularization of protected horticulture, many protected horticulture residues, which include vegetable stalks and fruit scrap, followed in recent years; and it is imperative to adopt a method of properly handling the residues. Protected horticulture residues have characteristics of high water content, high volatile solids content, and high biodegradability. If the residues are treated simply as general living garbage, it will lead to not only high costs but also a waste of resources. There are many studies abroad using anaerobic digestion processes to dealing with protected horticulture residues, while the domestic relevant reports are fewer. To obtain more detailed data about the biogas production characteristics of typical protected horticulture residues, and to explore the possibility of the application of Separated two phase anaerobic digestion (STP), in this study, five typical different protected horticulture residues are chosen as research subjects. The characteristics of five typical different protected horticulture residues-cucumber vine, tomato stem and leaves, pakchoi, watermelon vine, and grass are analyzed in this paper. Under a warm fermentation condition (38℃), the biogas production characteristics of these five raw materials are tested. In the condition of 38℃, watermelon vine, which has the best gas production performance, is chosen to test its adaptability of Separated two phase anaerobic digestion (STP), the biogas production characteristics of watermelon vine under two different reflux modes of spray and immersion is comparatively analyzed, and the main emphasis is on the pH variation of of leachate, biogas production, and methane concentration under two different reflux modes. All of these studies afford useful reference for the resource utilization of protected horticulture residues. The results show that the five protected horticulture residues have the same gas production tendency, reach a peak of gas production in the 3~4 days, and then the gas production declines and persists at a high level. Twenty days later, the gas production is low and stable; after 42 days, almost no gas is generated. These five protected horticulture residues have good gas production of anaerobic fermentation characteristics under warm temperature conditions, and all of them could be a good source for biogas fermentation. The sequence of the biogas potential in the five protected horticulture residues in watermelon vine, pakchoi, cucumber vine, tomato stem and leaves, and grass, and their unit dry mass gas production is 508.85, 458.93, 442.41, 410.17, and375.03 mL/g. Protected horticulture residues have good adaptability to Separated two phase anaerobic digestion (STP), which is shown as higher biogas production and higher methane concentrations. The spray mode of leachate is better suited than the immersion mode, and it has more biogas and higher methane concentrations. The total biogas production of the spray mode is 506.39L and its unit dry mass gas production is 481.21 L/kg, which is 10.81 percent higher than the immersion mode, and its methane concentration is basically stable between 53-56 percent, which was 6-12 percent higher than the immersion mode. In addition, the spray mode is generally more suitable for STP because of its greater stability.

       

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