超声预处理对餐厨垃圾与污泥两级厌氧消化的影响

发布时间：2018-12-22 09:29

【摘要】：餐厨垃圾和污水厂污泥均是城市有机固废的组成部分,随着经济的快速发展,城市化进程的推进,其产生量日益增长,如不妥善处置,会对周围环境带来诸多不良影响。厌氧发酵作为实现有机固废资源化利用的有效途径,成为目前国内外研究的重点。本试验通过对餐厨垃圾的超声预处理,以强化传统餐厨垃圾与污泥混合厌氧消化效能为目的,考察优化条件下餐厨垃圾与污泥混合两级厌氧消化工艺运行效果及经济效益。研究结果表明:(1)餐厨垃圾经超声预处理有助于提高其与污泥混合一级发酵水解产酸程度,促进含氮有机物的降解,对pH值影响不大,在4.2~5.0左右,能够实现产酸相和产甲烷相的分离;超声预处理能够适当的提高一级发酵产气量和产气率,但对产气成分的影响不大,H2含量都在80%以上。(2)通过VFAs、pH及氨氮浓度等指标变化情况可知,超声预处理对餐厨垃圾与污泥混合的二级发酵系统稳定运行影响不大,但能够将系统运行达稳定的时间缩短约7~10d。(3)不同的二级发酵投配率对超声预处理的效果产生一定的影响。当二级发酵投配率在较低的8%时,超声预处理的优势并不明显,此条件下有机物去除效果和产气效果与对照组差异不大,与对照组相比降解每克VS需要投入更多的能量;当二级发酵投配率提高到10%和12%时,超声组SCOD、TS和VS去除率均高于对照组,系统运行稳定超声组甲烷产率分别比对照组提高12.5%和13%,降解每克VS的能耗均低于对照组。(4)本试验的最佳工况为:餐厨垃圾经声能密度1.2W/mL、超声时间10min预处理后与污泥混合两级动态发酵,在二级投配率12%条件下,系统运行达稳定所需时间约为40d,总VS去除率为63.0%,产气率为801.46(mL/(gVS·d)),甲烷产率可达641.84(mLCH4/(gVS·d)),降解每克VS所投入的能量最少,经济效益最高。
[Abstract]:Kitchen garbage and sewage sludge are both components of organic solid waste in cities. With the rapid development of economy and the advancement of urbanization, the amount of waste produced is increasing day by day. If not disposed properly, it will bring many adverse effects to the surrounding environment. As an effective way to realize the utilization of organic solid waste, anaerobic fermentation has become the focus of research at home and abroad. The purpose of this experiment was to enhance the efficiency of mixed anaerobic digestion of traditional kitchen waste and sludge through ultrasonic pretreatment of kitchen waste. The effect and economic benefit of the two-stage anaerobic digestion process of mixed kitchen waste and sludge under optimized conditions were investigated. The results showed that: (1) Ultrasonic pretreatment of kitchen waste could improve the degree of hydrolysis and acid production, promote the degradation of nitrogen-containing organic matter, and have little effect on the pH value, which was about 4.20.0.The results showed that: (1) Ultrasonic pretreatment could improve the degree of acid production and promote the degradation of nitrogen-containing organic matter. The separation of acidogenic phase and methanogenic phase can be realized. Ultrasonic pretreatment could increase gas production and gas production rate of primary fermentation properly, but had little effect on gas components, and H _ 2 content was above 80%. (2) the changes of VFAs,pH and ammonia nitrogen concentration were analyzed. Ultrasonic pretreatment had little effect on the stable operation of the secondary fermentation system mixed with kitchen garbage and sludge. However, it can shorten the operation time of the system to about 7 ~ 10 days. (3) different secondary fermentation dosages have a certain effect on the effect of ultrasonic pretreatment. The advantages of ultrasonic pretreatment were not obvious when the rate of secondary fermentation was lower than that of the control group. The removal effect of organic matter and the effect of gas production under this condition were not different from those of the control group. Compared with the control group, more energy was needed for each gram of VS degradation. The removal rates of SCOD,TS and VS in the ultrasound group were higher than those in the control group, and the methane production rate of the stable ultrasound group was 12.5% and 13% higher than that of the control group, respectively, when the rate of secondary fermentation was increased to 10% and 12%, respectively. The energy consumption of each gram of VS degradation was lower than that of the control group. (4) the optimal conditions of this experiment were as follows: the noise energy density was 1.2 W / mL, the ultrasonic time was 10min pretreatment and the sludge was mixed with two stages of dynamic fermentation, under the condition of the two-stage mixing ratio of 12%. The operation time of the system is about 40 days, the total VS removal rate is 63.0, the gas production rate is 801.46 (mL/ (gVS d), methane production rate can be up to 641.84 (mLCH4/ (gVS d), degrades per gram of VS) the energy input is the least. The economic benefit is the highest.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703;X705

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