论文部分内容阅读
利用超声波对剩余污泥进行破解预处理,可以提高水解酸化产酸量与产酸速率,发酵温度是另一个影响水解酸化过程的因素.研究了弱超声(0.48 kW·L-1,5 min)、强超声(0.96 kW· L-1,15 min)预处理以及发酵温度(25、37和55℃)对水解酸化产酸量与产酸速率影响,并分析了挥发性脂肪酸(VFA)各组分浓度.研究表明,中温下进行水解酸化,超声预处理后产酸量较未处理时有明显增加.各发酵温度下,弱超声(0.48 kW·L-1,5 min)预处理与未处理相比,产酸速率相差不大,高温下进行水解酸化,各组VFA产量、产酸速率均较常温与中温条件下水解酸化有显著增加.此时,超声波预处理的作用不再明显,发酵温度成为影响VFA产量与产酸速率的主要因素.发酵过程中产生的VFA以乙酸为主.中温条件下各组乙酸百分含量均高于常温和高温条件.并且强超声破解会促进常温和中温酸化过程中2个C以上的有机酸产生,对高温条件该规律不再适用.“,”Ultrasonic disintegration is an efficient pretreatment method to improve volatile fatty acid (VFA) yields and production rates.The fermentation temperature also can have an effect on the hydrolytic acidification process.In this study,the effects of weak ultrasonic disintegration (0.48 kW · L-1,5 min),strong ultrasonic disintegration (0.96 kW · L-1,15 min),and fermentation temperature (25,37 and 55 ℃) on the hydrolytic acidification rate and VFA accumulation rate,as well as the VFA composition were investigated.Experimental results show that the VFA yield improved greatly after ultrasonic pretreatment when the fermentation temperature was 37 ℃.Under all fermentation temperatures,VFA production rates of control and weak ultrasonic disintegration groups differed only slightly.The VFA yield and production rate of each group at 55 ℃ increased much more than ones at 25 ℃ and 37 ℃.The effect of ultrasound was weak and fermentation temperature was the predominant factor influencing the acidification rate.In addition,acetic acid was the major VFA component during fermentation.Acetic acid reached the highest levels at 37 ℃ compared to the 25 ℃ and 55 ℃ treatments.Strong ultrasonic disintegration did promote the production of VFAs with two or more carbons during the acidification process when the fermentation temperature was 25 ℃ or 37 ℃;however,it was ineffective at 55 ℃.