Babel Sandhya, Fukushi Kensuke, Sitanrassamee Bunpot
Environmental Technology Program, Sirindhorn International Institute of Technology, Thammasat University, P.O. Box 22, Thammasat Rangsit PO, Pathumthani 12121, Thailand.
Water Res. 2004 May;38(9):2416-22. doi: 10.1016/j.watres.2004.02.005.
Laboratory scale experiments were carried out to evaluate and determine the suitable working conditions for the enhancement of volatile fatty acids (VFAs) production with the stabilization of solid pineapple waste (peel) simultaneously when operating two-phase anaerobic digestion. It was found that acid production, enhanced when the digester was operated at neutral pH. VFAs, could be obtained at about 50 g/kg-waste within 14 days when operating at pH 6.5-7.5 compared to 33 g/kg-waste for digester operated at pH 5.0-6.0 for 32 days. The total volatile solid reduction of 42-48% was obtained with a 51-57% volume reduction at neutral pH. The effect of undissociated acids on the activity of acetogenic bacteria was also studied. The inhibitory level of undissociated acids for acidogenesis was found to be about 2300, 650, and 120 mg/L at pH 5, 6, and 7, respectively. The results revealed that at low pH, undissociated acids are inhibitory. It was found that for efficient operation of two-phase anaerobic digestion, both VFAs concentration and pH should be controlled.
进行了实验室规模的实验，以评估和确定在两相厌氧消化过程中，同时稳定固体菠萝废弃物（果皮）时提高挥发性脂肪酸（VFAs）产量的合适工作条件。结果发现，当消化器在中性pH值下运行时，产酸量会增加。与在pH 5.0 - 6.0下运行32天的消化器产生33 g/kg废弃物的VFAs相比，在pH 6.5 - 7.5下运行时，14天内可获得约50 g/kg废弃物的VFAs。在中性pH值下，总挥发性固体减少了42 - 48%，体积减少了51 - 57%。还研究了解离酸对产乙酸菌活性的影响。发现解离酸对产酸作用的抑制水平在pH 5、6和7时分别约为2300、650和120 mg/L。结果表明，在低pH值下，解离酸具有抑制作用。研究发现，为了使两相厌氧消化高效运行，应同时控制VFAs浓度和pH值。
