【作者】 冯颖；

【导师】 陈旭； 康勇；

【作者基本信息】 天津大学 ， 化工过程机械， 2004， 博士

【摘要】 含重金属离子酸性废水是对环境污染最严重、对人类危害最大的工业废水,利用微生物代谢和硫循环原理处理此类废水是一门新兴技术。为了增强微生物在废水处理中的代谢活性,提高废水处理效率,本文通过对SRB和SRB+Fe⁰两种体系反应效果的比较,分析了各种因素影响反应效果的方式和机理,重点研究了Fe⁰对微生物硫酸盐还原代谢和重金属离子去除的强化作用和强化机理,并考察了利用SRB和Fe⁰协同处理实际矿山废水的效果。首先,通过间歇实验考察了温度、pH值和底物浓度等因素对SRB硫酸盐还原代谢的影响及Fe⁰在各种条件下的强化作用。结果表明,Fe⁰不但可以降低反应的活化能,增强体系对低温的耐受性,同时还可以减小pH值变化对硫酸盐还原速度的影响,加强微生物在高酸性条件下的代谢能力。另外,Fe⁰通过对酶活性的调节作用,增强酶对底物的结合能力,在相同的处理能力下,SRB+Fe⁰体系所需的底物浓度是SRB体系的75%。在此基础上,对SRB和SRB+Fe⁰两种体系的硫酸盐还原动力学进行研究,得到硫酸盐还原反应速度经验公式。其次,研究了重金属离子对SRB代谢的毒害作用、重金属的去除机理及Fe⁰的强化机理。提出了金属离子浓度与硫酸盐还原速度和还原率关系的模型,建立了重金属离子对SRB活性抑制作用的评估指标,即金属毒性系数β和50%活性抑制金属离子浓度Ic。得出了金属离子的毒性强弱顺序,Cr⁶⁺>Cu²⁺>Mⁿ⁺>Mn²⁺>Zn²⁺。金属离子混合后,其毒性比各种金属离子单独作用的效果增强。明确了各种金属离子的去除机理和去除形式,探讨了Fe⁰减小金属离子毒性,强化金属离子去除效果的机理。最后,考察了利用上流式复合填料反应器处理含重金属酸性废水的效果。结果表明,连续反应器中各种金属离子的毒性作用大大减弱,达到相同还原能力时,连续实验能承受的金属离子浓度是间歇实验的2⁶倍。在25℃下利用SRB+Fe⁰体系处理实际酸性矿山废水效果良好,体系SO₄^2-还原率为61%,pH值由进液的2.75上升到6.20,Cu²⁺浓度降至0.2mg·L^-1以下,达到废水排放标准,对Mn²⁺的去除效果不理想,去除率仅为53%。更多还原

【Abstract】 Acid wastewater containing heavy metal is a kind of industrial wastewater,which can induce the most serious environment pollution and do great harm to humanbeings. It is a new technique to treat this kind of wastewater with microbialmetabolism and sulfur cycle principle. In order to intensify the metabolism activitiesof microorganism in wastewater and improve the treatment efficiency, the followingworks have been done in this research. Function and mechanism of different factorson the reaction have been analyzed by comparing the reaction effects of SRB andSRB+Fe~0 system. Intensified function and mechanism of Fe~0 on biological sulfatereducing metabolism and the removing of the heavy metal have been studied onemphasis. On this basis, the treatment effect of mining drainage in SRB+Fe~0 systemwas researched.Firstly, the effect of temperature, pH and substrate concentration on SRBreducing metabolism and intensify function of Fe~0 under different conditions werestudied by intermittent experiments. It is shown that Fe~0 has functions of reducingactivation energy of reaction, enhancing the endurance capability of system to lowtemperature and eliminating the infection of pH variety on sulfate reducing rate, andintensifying the metabolism capability of microorganism under acidity condition. Inaddition, Fe~0 can enhance the appetency of bacteria with substrate by adjusting theactivity of enzymes. Substrate dosage needed in SRB+Fe~0 system is 75% that of SRBsystem under the same treatment capability. On this basis, sulfate reducing kinetics ofSRB and SRB+Fe~0 system were studied, and a series of experiential equations ofsulfate reducing rate were deduced.Secondly, toxicity of heavy metal on SRB metabolism, removing mechanism ofheavy metal and intensified function of Fe~0 in process were studied. Mathematicsmodel describing the relationship of metal concentration with sulfate reducing rateand reducing percent was proposed, in which toxicity coefficientβand metalconcentration Ic that restraining 50% metabolism activities were included as criterionsto evaluate the inhibition of metal to SRB activities. Toxicity order of different metalions is Cr6+>Cu2+>Mn+>Mn2+>Zn2+and toxicity of mixing metal is greater thansum of respective action effect of all metals. Removing mechanism and mode ofdifferent metals were specified. Mechanisms of Fe0 eliminating the toxicity andenhancing the removing effect of heavy metal were studied on emphasis.Lastly, treatment performance of acid wastewater containing heavy metal byup-flow multiple bed bioreactor was studied. It is shown that the toxicity of heavymetal in continuous reactor is weakened greatly and metal concentration standed bycontinuous reactor is 2~6 times that of intermittent reactor under the same treatmentcapability. Acid mining drainage is perfectly treated in SRB+Fe0 system under 25℃.Sulfate reducing percent is 61%, pH rises from 2.75 to 6.20 and concentrate of Cu2+drops to 0.2mg?L-1,which achieve the wastewater discharge standard. The removingof Mn2+ is not satisfied with removing percent is only 53%.更多还原