【作者】 张静；

【导师】 张代钧；

【作者基本信息】 重庆大学 ， 工程（环境工程）（专业学位）， 2019， 硕士

【摘要】 SO₂是我国主要的大气污染物之一,主要来源于煤等化石燃料的燃烧。工程上采用多种技术减少SO₂的排放,其中湿式氨法烟气脱硫技术被广泛应用。亚硫酸氢铵作为湿式氨法烟气脱硫工艺的主要产物,通常采用氧化法进行回收,但氧化过程中存在氧化效率不高、设备复杂等不足,因此,探索其他途径有效氧化亚硫酸铵或同时脱除吸收液中的铵和亚硫酸盐具有重要意义。本世纪初有研究报道了厌氧氨氧化混合培养物能够催化以硫酸盐作为电子受体的厌氧氨氧化。基于热力学的分析,更有利于发生以亚硫酸盐作为电子受体的厌氧氨氧化反应。论文在膨胀颗粒污泥床（EGSB）反应器中接种亚硝酸盐型厌氧氨氧化污泥,直接以亚硫酸盐作为电子受体启动和驯化亚硫酸盐型厌氧氨氧化;在微生物燃料电池（MFC）中接种亚硝酸盐型厌氧氨氧化污泥,研究证实污泥中存在电活性微生物催化氨氧化;通过改变进水中的Fe（Ⅱ）浓度,研究亚硫酸盐型厌氧氨氧化EGSB反应器脱氮性能的变化;最后,取亚硫酸盐驯化前后的污泥做16S rRNA基因高通量测序,分析细菌群落结构变化,推测体系中可能存在的氮、硫转化途径,为发展湿式氨法烟气脱硫生产（NH₄）₂SO₄的替代技术提供参考。得出的主要成果和结论如下:（1）将亚硝酸盐型厌氧氨氧化反应器进水基质中的NO₂^-直接更换为SO₃^2-后,反应器能实现SO₃^2-和NH₄⁺的同步转化。在更换基质运行的28天里,NH₄⁺基本以N₂的形式脱除,去除速率基本稳定在300mgN/（L·d）,但此后NH₄⁺-N脱除量不再随进水SO₃^2-浓度的升高而提高。大部分SO₃^2-转化为SO₄^2-,有硫化物但无单质硫产生。（2）改变进水中亚铁离子的浓度来提升反应器的运行性能,结果表明,当亚铁离子浓度为6mg/L时脱氮负荷达到最大（400mgN/（L·d））,△NH₄⁺-N/△SO₃^2--S（两者物质的量浓度变化量之比）介于1.02².01之间。利用单室空气阴极MFC反应器实验,证实了厌氧氨氧化污泥中存在电活性微生物经由胞外电子传递途径氧化NH₄⁺,认为提高进水亚铁离子浓度一方面可沉淀硫化物、补充微量元素,另一方面可以强化胞外电子传递过程,提升EGSB反应器的脱氮性能。（3）亚硫酸盐驯化前后的两个污泥样本中检测到两个具有厌氧氨氧化功能的菌属——Candidatus Kuenenia、Candidatus Jettenia,它们的相对丰度在培养前后呈现此消彼长。二者相对丰度之和占比重较大,表明厌氧氨氧化菌在驯化过程中始终保持了较好的活性,但厌氧氨氧化菌能否直接利用SO₃^2-进行厌氧氨氧化还需要进一步验证。经亚硫酸盐驯化后的厌氧氨氧化污泥中出现了Thiobacillus,其在驯化后的污泥样品中的相对丰度达到了2.79%,推测体系中可能存在硫自养反硝化这一过程。此外,两个污泥样品中均未检测到硫酸盐型厌氧氨氧化体系的优势菌Bacillus benzoevorans,表明亚硫酸盐型厌氧氨氧化体系与硫酸盐型厌氧氨氧化体系存在显著差异。更多还原

【Abstract】 SO₂ is one of the major air pollutants in China,which not only directly damages human health,but also causes acid deposition,endangers aquatic ecosystem and affects human production and life.The combustion of coal and other fossil fuels are the main sources of SO₂.A variety of technologies are adopted to reduce the emission of SO₂.Among them,the wet ammonia flue gas desulfurization technology with its superiority of product recycling and high desulfurization efficiency is extensively used.NH₄HSO₃,which is the main products of the wet ammonia flue gas desulfurization process,are exported from absorption system firstly,then neutralized by ammonia to（NH₄）₂SO₃,oxidized to（NH₄）₂SO₄ fertilizer finally.But the oxidation process have some defects,such as the low oxidation efficiency and high requirements for equipment,therefore,to explore effective（NH₄）₂SO₃ oxidation or other ways at the same time removing NH₄⁺and SO₃^2-in absorbing liquid is of great significance.At the beginning of this century,it was reported that the mixed culture of anammox could catalyze the ammonia oxidation under anaerobic conditions with SO₄^2-as the electron acceptor.Based on thermodynamic analysis,the ammonia oxidation with SO₃^2-as electron acceptor is more favorable.In this study,firstly,nitrite-depedent anammox sludge was inoculated in an expanded granular sludge bed（EGSB）reactor,sulfite-depedent anammox reaction was started up and acclimated with sulfite as the only electron acceptor.Secondly,nitrite-depedent anammox sludge was inoculated in the microbial fuel cell（MFC）to confirm the existence of ammonia oxidation catalyzed by electroactive microorganisms in the sludge,and the effect of Fe（Ⅱ）concentration on sulfite-depedent anammox reactor denitrification performance was explored.Finally,16S rRNA gene high-throughput sequencing technology was used to detect the changes of microbial community structure in the EGSB reactor,the potential biology mechanisms on transformation of nitrogen and sulfur was analyzed,so as to provide a reference for the development of an alternative technology of wet ammonia flue gas desulfurization production（NH₄）₂SO₄.The main conclusions are as follows:（1）The NO₂^-in anammox reactor influent was directly replaced by SO₃^2-,synchronous conversion of NH₄⁺and SO₃^2-was achieved.After the substrate was replaced,the ammonium salt was basically removed in the form of N₂,and the removal rate was basically stable at 300mgN/（L·d）,but thereafter the removal amount of NH₄⁺was no longer increased with the increase of the concentration of SO₃^2-in influent.SO₃^2-were converted to SO₄^2-largely,and a small quantity of sulfide,but no sulfur.（2）The concentration of Fe（Ⅱ）was adjusted to explore changes of the reactor performance.Results showed that,the removal rate of total nitrogen could reach more than 400mgN/（L·d）when the concentration of Fe（Ⅱ）was 6mg/L,△NH₄⁺-N/△SO₃^2--S ranged from 1.02 to 2.01.The experiment of single-chamber air cathode MFC reactor proves the existence of denitrification pathway via extracellular electron transfer in the anammox system.It is believed that increasing the concentration of Fe（Ⅱ）not only can precipitate sulfide,supply trace elements,but also strengthen the extracellular electron transfer in the anammox system.（3）Candidatus Kuenenia and Candidatus Jettenia with the function of anammox were detected in two sludge samples,but their relative abundance changed a lot.However,the sum of relative abundance of the two still accounts for a large proportion,indicating that the anammox bacteria always maintain good activity during domestication,but whether the anammox bacteria can use SO₃^2-needs further verification.After the anammox sludge was domesticated by SO₃^2-,the relative abundance of Thiobacillus was up to 2.79%in sample 1-2,suggesting that there might be a process of sulfur autotrophic denitrification in the system.In addition,the dominant bacterium Bacillus benzoevorans of the sulfate anammox system was not detected in two sludge samples,indicating that there were significant differences between the SO₃^2-anammox system and the SO₄^2-anammox system.更多还原