Faculty of Engineering, Hokkaido University, N13, W18, Kita-ku, Sapporo 060-8628, Japan.
Waste Manag. 2016 Feb;48:430-439. doi: 10.1016/j.wasman.2015.10.009. Epub 2015 Oct 17.
The high methane gas production potential of two phase olive milling waste (2POMW) makes its application to biogas plants in business an economical process to increase the productivity of the plants. The objective of this study was to investigate the appropriate conditions for the codigestion of NaOH-pretreated 2POMW with food waste. NaOH pretreatment can increase the methane production by increasing the soluble chemical oxygen demand (sCOD), but it may cause inhibition because of higher levels of alkalinity, sodium ion, volatile fatty acids and long chain fatty acids (LCFAs). Therefore, the first experimental phase of this study aimed to investigate the effect of different mixing ratios of 2POMW to food waste. A continuous stirred tank reactor experiment with different mixing ratios of 3%, 4.3%, 5.7% and 8.3% (2POMW: food waste) was conducted. NaOH pretreatment in the range of 6-20% was used. A mixing ratio up to 4.3%, when 10% NaOH pretreatment was used, caused no inhibition and increased methane production by 445.9mL/g-VS(2POMW). For this mixing ratio an additional experimental phase was conducted with the 20% NaOH pretreatment as the 20% NaOH pretreatment had the highest sCOD. The methane gas production was increased by 503.6mL/g-VS(2POMW). However, pH adjustment was required for applying this concentration of the high alkalinity 20% NaOH-pretreated 2POMW. Therefore, we consider using 10% NaOH pretreatment in a mixing ratio of 4.3% to be more applicable. The increase in methane gas production was correlated to the oleic acid concentration inside the reactors. The high oleic acid concentration of 61.8mg/L for the 8.3% mixing ratio was responsible for the strong inhibition. This study showed that adjusting the appropriate mixing ratio of the NaOH-pretreated 2POMW could increase the electricity production of a reactor that regularly receives food waste.
两相橄榄加工废物（2POMW）具有较高的甲烷气体产生潜力，将其应用于沼气厂是一种经济的工艺，可以提高工厂的生产力。本研究的目的是研究在碱性预处理两相橄榄加工废物（NaOH-Pretreated 2POMW）与食物废物共消化的适宜条件。NaOH 预处理可以通过增加可溶化学需氧量（sCOD）来增加甲烷产量，但由于较高的碱度、钠离子、挥发性脂肪酸和长链脂肪酸（LCFAs）水平，可能会引起抑制。因此，本研究的第一阶段旨在研究不同 2POMW 与食物废物混合比例的影响。进行了不同混合比例为 3%、4.3%、5.7%和 8.3%（2POMW：食物废物）的连续搅拌槽式反应器实验。使用了 6-20%的 NaOH 预处理。当使用 10%NaOH 预处理时，混合比例高达 4.3%不会引起抑制，并且将甲烷产量提高了 445.9mL/g-VS（2POMW）。对于该混合比例，进行了一个额外的实验阶段，使用 20%NaOH 预处理，因为 20%NaOH 预处理具有最高的 sCOD。甲烷气体产量提高了 503.6mL/g-VS（2POMW）。然而，需要进行 pH 调节才能应用这种高碱性 20%NaOH 预处理的 2POMW。因此，我们认为在 4.3%的混合比例下使用 10%NaOH 预处理更适用。甲烷气体产量的增加与反应器内油酸浓度相关。对于 8.3%的混合比例，高油酸浓度为 61.8mg/L，导致强烈的抑制。本研究表明，调整适当的 NaOH 预处理两相橄榄加工废物（NaOH-Pretreated 2POMW）混合比例可以增加定期接收食物废物的反应器的电力产量。
