Microbial activity in stockpiled bagasse was investigated using: (1) acidity levels within the stockpile and (2) detected amounts of flammable volatile organic compounds (VOCs) above the stockpile, as potential factors to identify their impacts on spontaneous combustion. Temperature, moisture content, microbial activity (estimated by the number of spores obtained from plate counting), pH value, amount of acetic acid at different depths (0.5, 1.0, 1.5, 2.0 and 2.5 m from the stockpile surface) and the flammable VOCs above the stockpile surface after different storage periods (100, 150, 200 and 250 days from the first stockpiled day) were investigated. The temperature and moisture content of the stockpile were in the ranges 50–65 °C and 50–65%, respectively. A decrease in the pH value (pH 4 to 3) after longer storage periods was observed, which was related to the decreases in mesophile spores (1 order of magnitude) and thermophiles spores (1 order of magnitude) within the stockpile. Increases were observed in the temperature (5–10 °C), in the production of acid (3.6% m/m on dried bagasse) and of flammable VOCs, such as ethanol in the range 118–130 µg per cubic meter of air and others above the stockpile. Acid production increased the flammable VOCs, the temperature and the moisture content, suggesting that these parameters have the potential to be used for monitoring the stockpile characteristics. The acidity level is particularly useful since it is easy to measure.

中文翻译：

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甘蔗渣库存中的自燃趋势：生物和非生物反应关系

使用以下方法研究了储存的甘蔗渣中的微生物活性：（1）储存物中的酸度水平和（2）检测到储存上方的易燃挥发性有机化合物（VOC）的量，作为识别其对自燃的影响的潜在因素。温度，水分含量，微生物活性（通过平板计数获得的孢子数量估算），pH值，不同深度（距储存表面0.5、1.0、1.5、2.0和2.5 m）的乙酸量和易燃的VOC在不同的储存期（从第一次储存之日起100、150、200和250天）之后，对堆料表面上方的水分进行了调查。储存的温度和含水量分别在50-65°C和50-65％的范围内。长期保存后，pH值降低（pH 4至3），这与库存中嗜温菌孢子（1个数量级）和嗜热菌孢子（1个数量级）的减少有关。观察到温度（5–10°C），酸的产生（干蔗渣的3.6％m / m）和易燃VOC的增加，例如乙醇的浓度范围为每立方米空气118–130 µg。其他高于库存的。产酸增加了易燃的挥发性有机化合物，温度和水分含量，表明这些参数具有用于监测储存特性的潜力。酸度水平因为易于测量而特别有用。在干燥的甘蔗渣上为6％m / m）和易燃的VOC，例如每立方米空气中118-130 µg的乙醇和其他高于储存的VOC。产酸增加了易燃的挥发性有机化合物，温度和水分含量，表明这些参数具有用于监测储存特性的潜力。酸度水平因为易于测量而特别有用。在干燥的甘蔗渣上为6％m / m）和易燃的VOC，例如每立方米空气中118-130 µg的乙醇和其他高于储存的VOC。产酸增加了易燃的挥发性有机化合物，温度和水分含量，表明这些参数具有用于监测储存特性的潜力。酸度水平因为易于测量而特别有用。