【作者】 邓志华；

【导师】 宁平； 周成；

【作者基本信息】 昆明理工大学 ， 环境工程， 2013， 博士

【摘要】 天然橡胶因为具有较强的弹性,较好的绝缘性和可塑性等性能被广泛地用于工业、农业、国防、交通等领域,在国民经济发展过程中具有举足轻重的地位。天然橡胶生产过程中产生的废气具有恶臭气味,对环境造成臭气污染。因此,控制天然橡胶企业的恶臭气体污染成为实现天然橡胶产业可持续发展的必然选择。论文对天然橡胶厂的臭气成分进行了来源解析；针对两类恶臭成分筛选和驯化降解微生物；在此基础上,以焦炭和磷矿石作为基质固定相应的降解菌对橡胶厂主要恶臭成分进行降解,最后对降解过程和降解机理进行机理分析,主要内容如下：(1)建立了天然橡胶厂废气分析方法。采用GC/MS联用仪、GC仪和紫外-可见分光光度仪等仪器对固体橡胶释放出的臭气和天然橡胶厂大气环境中的臭气污染状况进行了调查和分析。结果表明,天然橡胶厂释放的臭气物质包括羰基化合物、硫类、胺类、芳香烃、醇类等6类,涉及37种物质。其中挥发性脂肪酸(VFAs)、氨气、硫化氢和甲硫醚是天然橡胶厂恶臭气体的特征污染物,是造成恶臭污染的主要来源；(2)构建了生物滴滤床反应器。以甲酸、丙酸和正戊酸(质量比为1：1：1)的混合物天然橡胶厂产生的挥发性脂肪酸臭气,并将混合物作为唯一碳源从天然橡胶厂生产废水处理站的活性污泥中分离、获得降解菌—DA-1。在此基础上,以焦炭和磷矿石作为反应器的基质并固定DA-1菌,分别构建了1#和2#生物滴滤反应器对挥发性脂肪酸臭气进行净化。结果表明,在进气浓度205.80-677.40mg/m3,营养液pH6.0-7.0的条件下,反应器对挥发性脂肪酸的体积去除负荷随运行时间增加而呈逐渐增加的趋势；以甲硫醚为唯一碳源从天然橡胶厂生产废水处理站的活性污泥中分离出3株优势菌,被命名为DJ-1、DJ-2和DJ-3,其中DJ-2菌的菌落最大。DJ-2菌的最佳生长条件为：pH=7、t=30℃、C/N=5。以焦炭和磷矿石为基质固定DJ-2菌,分别构建了3#和4#生物滴滤反应器对甲硫醚臭气进行降解。第45天,3#和4#塔对甲硫醚的体积去除负荷分别达到6.60g/(m3.h)和6.08g/(m3-h)；对4个生物滴滤反应器的净化效果进行综合分析后发现,以焦炭为填料的生物反应器净化效果更好。其原因可能在于焦炭相对于磷矿石具有更大的比表面积、空隙率和更强的持水性。理化性质分析结果表明：焦炭的比表面积、持水率和空隙率分别为312.40m2/g、28%和45.98%,各项参数均优于磷矿石的0.38m2/g、7.5%和43.76%；构建了两套新型生物滴滤反应器,其中一套(5#)反应器的下半层填料以挥发性脂肪酸(VFAs)为唯一碳源驯化和挂膜,上半层填料以甲硫醚为唯一碳源驯化和挂膜。另一套(6#)反应器的填料构成正好与5#反应器相反,即上半层填料以挥发性脂肪酸(VFAs)为唯一碳源驯化和挂膜,下半层填料以甲硫醚为唯一碳源驯化和挂膜。利用这两个复合生物反应器对甲硫醚和VFAs的混合气体进行净化,考察了反应器的运行状况和净化效果。实验结果表明,5#反应器和6#反应器都对甲硫醚和VFAs表现出一定的净化能力,两个反应器都有一定抗负荷冲击能力。尤其是在低浓度阶段,两个反应器都对混合臭气表现出了较好的净化能力。但在高浓度阶段,6#反应器对甲硫醚的净化效果不好,净化率随进气浓度的增加出现急剧下降的趋势。当VFAs和甲硫醚进气负荷分别为2.12g/(m3.h)和5.71g/(m3.h)时,反应器对甲硫醚的净化率降为53.13%。实验结果还表明,在降解甲硫醚的反应器中引入低浓度的VFAs有利于甲硫醚的去除,当VFAs浓度偏高时会抑制甲硫醚的降解。在降解VFAs的反应器中引入甲硫醚对VFAs的净化效果没有明显影响；(3)对VFAs和甲硫醚的降解机理进行了分析。结果认为,氧气是影响VFAs和甲硫醚降解最重要的因素之一。在氧气供应充足的条件下,两类物质所进行的降解反应都以好氧反应为主,VFAs最终降解产生CO2和H2O,甲硫醚最终降解产生H2SO3;在厌氧条件下,两类物质都主要进行厌氧反应,VFAs最终降解产生CO2和CH4,甲硫醚最终降解产生H2S。更多还原

【Abstract】 Raw material products from natural rubber processing plants provide huge benefits to human beings as they are exploited to manufacture many kinds of important rubber goods. However, a large number of odorous substances have been produce during the production process of natural rubber. The contradictions between the development of rubber production and environmental protection have become increasingly prominent with the expansion of rubber production. Therefore, it is need that using environmental friendly methods to solve the problem of odor pollution.In this paper, the main odor components resulting from the production process of natural rubber were analyzed and the odor-degrading microorganisms have been isolated based on those odor components. Furthermore, six biotrickling filters were designed and made, which were characterized by using coke and phosphate rock as the packing to immobilize the odor-degrading microorganisms and then to degrade the odor components producing the process of natural rubber production, respectively. In addition, the degradation mechanisms were explored. The results were showed as follow:(1) The odor components resulting from the production process of natural rubber were analyzed using UV spectrophotometer, gas chromatography and gas chromatography/mass spectrometry (GC/MS) associated with head space sampling technique. The results showed that the odorous components from the natural rubber plant include amines, ketones, ethers, acids, et al., Of which, volatile fatty acid, ammonia, hydrogen sulphide and methyl sulfide were identified as the typical components;(2) A volatile fatty acids-degrading microorganism, DA-1, was isolated from the sludge from wastewater treatment plant of natural rubber production by using formic acid, propionic acid and n-valeric acid (the quality ratio:1:1:1) as odor and carbon source. Further, DA-1was immobilized on coke (reactor1) and phosphate rock (reactor2), which used to degrade volatile fatty acids in the two biotrickling filters, respectively. The results showed that the elimination capacity of volatile fatty acids always increased during the experiment at the inlet concentration of205.80-677.40mg/m3and pH of6.0-7.0; A methyl sulfide-degrading microorganism, DJ-1, DJ-2and DJ-3were isolated from the sludge of wastewater treatment plant of natural rubber production by using dimethyl sulfide as carbon source. The optimum growth conditions for DJ-2were pH7,30℃, and C/N ratios of5. Further, DJ-2was immobilized on coke (reactor3) and phosphate rock (reactor4), which used to degrade the dimethyl sulfide in the two biotrickling filters, respectively. The results showed that the elimination capacity of dimethyl sulfide reached6.60g/(m3-h) in reactor3and6.08g/(m3·h) in reactor4at odor flow rate of0.50L/min and pH of6.0-7.0on the45th day; The biotrickling filter using coke as the packing was better than that using phosphate rock as the packing. The reason probably lied that coke with respect to the phosphate rock having a larger specific surface area and porosity, greater water holding capacity, and thus demonstrate better purifying capability because coke has a specific surface area of312.40m2/g, the water holdup of28%and the porosity of45.98%, while phosphate rock has a specific surface area of0.38m2/g, the water-holding rate of7.5%and a porosity of43.76%; Two sets of biotrickling filters were built, one (reactor5) packed with volatile fatty acids-degrading microorganism in the lower part and the other (reactor6) packed with methyl sulfide-degrading microorganism in the upper parter. Further, the two biofilters to be used to degrade the mixtures of volatile fatty acids and methyl sulfide from air streams. The results showed that reactor5and6both can withstand shock loading and will maintain stably under relative low concentration of odorous volatile fatty acids and methyl sulfide inlet gas. However, the bioreactor6was ineffective in removing methyl sulfide under the inlet load too high. The purification rate of dimethyl sulfide dropped to53.13%at VFAs mass loadings up to5.71g/m3-h and methyl sulfide loadings up to2.12g/m3-h;(3) In addition, the mechanism about the degradation of volatile fatty acids and dimethyl sulfide were explored. The results showed that oxygen played an important role in the biological degradation process. The VFAs and dimethyl sulfide would be degraded to CO2, H2O and H2SO3provided the oxygen was supplied sufficiently. In contrast, the VFAs and dimethyl sulfide would be degraded to CO2, CH4and H2S respectively.更多还原