【作者】 郑国臣；

【导师】 李建政；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2010， 博士

【摘要】 厌氧发酵技术是解决环境污染及能源需求问题的重要途径。本文针对常见的连续流搅拌槽式反应器(CSTR)和厌氧折流板反应器(ABR)两类反应器在发酵制氢和甲烷发酵中存在的理论和技术问题,开展了发酵产氢产甲烷系统的调控技术研究,并探讨ABR同步产氢产甲烷的的可行性,进一步研究了提高其效能的技术措施。以好氧污泥为启动接种物的CSTR发酵制氢系统的研究表明,通过工程控制技术,可以在系统内定向培育出丙酸型发酵、丁酸型发酵和乙醇型发酵等代谢类型不同的微生物群落,其中乙醇型发酵是厌氧活性污泥系统发酵产氢的最佳类型,其比产氢速率为2.89 mol/kgMLVSS·d,是丁酸型发酵的4倍,是丙酸型发酵的148倍。在CSTR发酵制氢系统中,其产氢机制主要为丙酮酸脱羧产氢和辅酶Ⅰ氧化还原平衡调节产氢,其产氢量对反应器总产氢量的贡献分别为82%和18%,而产氢产乙酸作用未得到发挥。同时发现,较低的污泥负荷率对乙醇型发酵的形成具有显著的促进作用。在相同条件下,CSTR启动污泥负荷为0.99 kgCOD/kgMLVSS·d,达到稳定乙醇型发酵的时间为30 d,而当污泥负荷降低为0.64 kgCOD/kgMLVSS·d时,乙醇型发酵的启动则可在16 d内完成。为解决CSTR发酵制氢系统存在的单位基质氢气转化率低及因搅拌带来的耗能问题,开展了ABR系统发酵产氢研究。结果表明,ABR是一种较为理想的有机废水发酵制氢反应设备,与CSTR相比,具有较高的微生物产氢活性、较低能源消耗等优点。在HRT 13.5 h、35℃和进水COD 5000 mg/L条件下,系统可在26 d达到乙醇型发酵,其比产氢速率为0.13 L/gMLVSS·d,而CSTR在同样条件下的比产氢速率仅为0.06 L/gMLVSS·d。在一定控制条件下,CSTR和ABR两类反应器内均可建立起完整的甲烷发酵微生物体系。CSTR在进水COD浓度为4000 mg/L、HRT为24 h等条件下,可以在73 d形成具有完整甲烷发酵过程的絮状悬浮厌氧活性污泥系统,其COD去除率维持在70%左右。而ABR以厌氧絮状污泥接种时,在进水COD、HRT相同的情况下,其COD去除率在17 d后即可达到74%,在有机负荷为4 kg/m3·d,COD去除率可稳定在90%以上。提出了借助ABR构建发酵联合产氢-产甲烷系统的技术思想,通过前端格室发酵产氢、后端格室发酵产甲烷的生物相功能调控,构建成功ABR发酵联合产氢-产甲烷系统,在进水COD 6000 mg/L、ALK 1900 mg/L条件下,系统的COD去除率提高到62%以上,产氢能力达到0.37 m~3/m~3·d,产甲烷能力达到1.66 m~3/m~3·d。研究表明,碱度调节可有效刺激ABR发酵联合产氢-产甲烷系统中厌氧活性污泥的增殖和产甲烷活性,但对前端格室厌氧活性污泥的发酵产氢所用有所抑制;而微量元素则对所有微生物类群的活性具有很好的提升效果,并可有效增加系统的生物多样性,但对微生物增殖的促进作用不显著。无论是进水COD浓度的改变、碱度的变化,还是微量元素的投加,都会引发ABR发酵联合产氢-产甲烷系统中微生物群落的演替,各格室厌氧活性污泥的群落构成也呈现有规律的更迭。在研究产氢氢化酶活性测定影响因素的基础上,优化并确立了一种具有较高灵敏度的产氢氢化酶活性测定方法,采用该方法检测到的产氢氢化酶活性,与ABR活性污泥的比产氢速率具有高度相关性,可用于评价ABR产氢效能。更多还原

【Abstract】 Anaerobic fermentation technology is an important route to solve environmental pollution and resources problems. In this paper, the theoretical and technical characteristics of CSTR and ABR (anaerobic baffled reactor) during fermentation hydrogen production and methane fermentation were explored, and the adjustment of fermentation hydrogen-methane production was researched. Furthermore, the simultaneous hydrogen-methane production was tested and optimized.The CSTR fermentation hydrogen production system was initialed using aerobic sludge, and different anaerobic microorganisms were cultured to achieve propionic acid type fermentation, butyric acid type fermentation, and ethanol type fermentation. Ethanol type fermentation was the optimum one among all these types; the specific hydrogen production efficiency was 2.89 mol/kgMLVSS·d, 4 times that of butyric acid type fermentation and 148 times that of propionic acid type fermentation. In CSTR, the hydrogen production mechanisms included pyruvate decarboxylation hydrogen production and coenzymeⅠhydrogen redox balance adjustment, and their contributions were 82% and 18% respectively. Hydrogen-producing acetogens did not work. Lower sludge loading rate was beneficial to the formation of ethanol-type fermentation. It took 30 days to achieve stable ethanol-type fermentation when the sludge load was 0.99 kgCOD/kgMLVSS·d during start-up or 16 days when the load was 0.64 kgCOD/kgMLVSS·d.Results showed that ABR was an ideal facility for hydrogen production from organic wastewater fermentation. It had higher efficiency and lower energy consumption comparing with CSTR. ABR achieved stable ethanol type fermentation within 26 d with HRT of 13.5 h, 35℃and initial COD of 5000 mg/L, and the specific hydrogen production rate was 0.13 L/gMLVSS·d while that of CSTR under the same conditions was 0.06 L/gMLVSS·d.Both CSTR and ABR could establish complete methane fermentation microbial systems under certain controlled conditions. With an influent COD concentration of 4000 mg/L and HRT of 24 h, CSTR could form a suspended anaerobic sludge system with complete methane fermentation process within 73 d and the COD removal ratio was around 70%. Under the same conditions, ABR could achieve 74% COD removal within 17 d, and further improved to 90% COD removal with an organic load of 4 kg/m3·d.Based on above findings, simultaneous hydrogen-methane fermentation was proposed and realized in the ABR system. The first two compartments functioned as hydrogen production, while the last ones acted as methane production. When influent COD was 6000 mg/L and ALK was 1900 mg/L, COD removal ratio reached 62%, hydrogen production capacity reached 0.37 m~3/m~3·d, and methane production capacity was 1.66 m~3/m~3·d. Alkalinity adjustment could stimulate the proliferation and methanogenic activity of sludge in the back compartment’but inhibited the hydrogen production in front compartments. Trace element addition, on the other hand, stimulated the activity of all types of microorganisms, enhanced the bio-diversity of ABR, but did not change the amount of biomass. The influent COD change, alkalinity adjustment, and trace element addition caused succession of the microorganism communities in ABR. Accordingly, the microbial communities’formation in each compartment presented a regular variation.A novel method was built to measure the activity of hydrogen production hydrogenase. The hydrogenase activity measured using this method was highly relevant with the specific hydrogen production efficiency of the ABR, and, thus, could be used to evaluate the performance of ABR.更多还原