【作者】 董永亮；

【导师】 刘广民；

【作者基本信息】 哈尔滨工程大学 ， 环境工程， 2008， 硕士

【摘要】 果蔬废弃物作为固体废弃物的一部分,其含水率大、有机物质及营养元素含量高,非常适于厌氧消化处理,同时能产生生物能沼气,使垃圾减量和能源再生相结合,具有很大的发展潜力和应用前景。本文采用自行设计的小试规模反应装置,在中温35℃条件下两相厌氧消化处理固体果蔬废弃物,通过三个阶段的运行试验,对果蔬废弃物厌氧消化运行特征及效果进行了分析,研究了果蔬废弃物产酸发酵类型、产甲烷相对消化产物的利用顺序、COD去除效果、产气量及果蔬固体减量情况,并考察了果蔬废弃物在不同有机负荷下的厌氧消化运行效果及产能情况。反应启动阶段,将果蔬废弃物切制成块,通过反应液在系统中回流运行,启动反应装置。启动后厌氧消化运行稳定,果蔬废弃物厌氧消化发酵类型为丁酸型发酵;产甲烷相对挥发酸的利用顺序为乙醇＞丁酸＞戊酸＞丙酸＞乙酸,产甲烷阶段体系ORP为-480mV左右,厌氧环境良好;COD去除率达80%以上;同时,果蔬固体物质去除率达到98.6%,果蔬废弃物减量效果明显。但此阶段厌氧消化时间长,单位时间COD去除率低,产气量少,厌氧消化处理效率较低。低负荷运行阶段,通过保持低负荷进水状态,人工调控消化环境来优化第一阶段的厌氧消化体系,提高反应装置处理效率。经过一段时间的调整,反应器内挥发酸含量和钠离子浓度降低,厌氧微生物逐渐适应环境,厌氧消化处理效率逐渐提高。反应体系在低有机负荷进水下运行良好,果蔬固体物质去除率达87%以上,最高产气量为35L/d,单位体积产气量为0.7L/L·d,进水中单位质量COD产气量为0.44L/gCOD,甲烷含量在50%以上;COD去除率为70%～80%,出水COD值可低至70mg/L。高负荷运行及产能阶段,在低负荷运行阶段消化处理效率提高后,反应体系缓冲能力增强、果蔬废弃物预酸化时间减少、COD去除效率增加、产气量提高。通过逐渐提高有机负荷值,得出该反应装置最高有机负荷可达9gCOD/L·d;随着有机负荷的提高,COD去除量及产气量逐渐升高,并于7.2gCOD/L·d以上后趋于稳定;期间,果蔬废弃物厌氧消化反应体系最大产气量为200L/d,最高容积产气量为4L/L·d,最高单位质量COD产气量为0.7L/gCOD,降解单位质量COD时最高产气量为0.56L/gCOD,甲烷含量占70%左右,同时最高单位容积COD去除量为5g/L·d。更多还原

【Abstract】 The fruit and vegetable wastes(FVW),with high content of water,organic matters and nutrient content,are suitable to anaerobic digestion processing extremely;simultaneously the biological energy methane can be produced.The anaerobic digestion of FVW has great development potential and application prospect for combining solid waster’s decrement and energy regeneration together. Using two-phase anaerobic digestion to treat fruit and vegetable wastes under mesophilic conditions(35℃),the fermentation type,use order of digestion product in methane production phase,the removal efficiency of COD,The biogas yield and solid decrement effect of FVW were studied by three stages experiment in a self-designed pilot-scale reactor.Furthermore,the anaerobic digestion process and energy production were evaluated under different organic loading.The results and conclusions were showed as follows.At the start-up stage,the anaerobic digestion was running stably after reactor start-up successfully.The fermentation type was butyric acid type;the use order of VFA in methane production phase showed as follow:ethanol＞butyric acid＞valeric acid＞propionic acid＞acetic acid,the ORP in methane production phase was about -480mV,COD removal was above 80%,solid removal of FVW was 98.6%,the decrement effect of FVW was obvious.However,the anaerobic digestion processing inefficiency caused long digestion time,low removal rate of COD and biogas production.At the low organic loading stage,aiming to improve treatment efficiency,the first stage anaerobic digestion system was optimized by keeping low organic loading and controlling digestion environment.With anaerobic microorganism adapting environment gradually,processing efficiency obtained the enhancement after artificial regulation;anaerobic digestion system was running well on low organic loading,respectively,the solid removal of FVW was above 87%,the largest biogas production and biogas production per influent concentration COD can reach 35L/d and 0.44L/gCOD respectively,percentage of methane was above 50%.The COD removal rate and effluent concentration of COD can reach 70%～80%and 70mg/L.At high organic loading stage and energy production,the buffering capacity was improved,pre-acidification was shorted,and the removal efficiency and biogas yield were increased in digester after enhancing the digestion efficiency in second stage experiment.The maximum organic loading of digester can reached 9gCOD/L·d.With the organic loading being increased,the removal concentration of COD and biogas yield were increasing gradually,and tended to stably after 7.2gCOD/L·d.Meanwhile,the largest biogas production,biogas production per influent COD concentration and biogas production per degradable COD concentration reached 200L/d,0.7L/gCOD and 0.56L/gCOD respectively,with about 70%of methane content and 5g/L·d of removal rate of COD in anaerobic digestion process of FVW.更多还原