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题名: Fenton氧化-两相UASB-SBR耦合工艺处理腈纶废水实验研究
作者: 李津
学位类别: 博士
答辩日期: 2011
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 栾兆坤
关键词: 腈纶生产废水 ; acrylic fiber manufacturing wastewater ; Fenton氧化 ; Fenton oxidation ; 两相UASB ; two-stage UASB ; SBR ; SBR ; 颗粒污泥 ; granular sludge ; 胞外聚合物 ; extracellular polymeric substances (EPS) ; 硫酸盐还原菌 ; sulfate-reducing bacteria (SRB) ; 产甲烷菌 ; methane-producing archaea (MPA) ; 短程硝化 ; shortcut nitrification
其他题名: Treatment of Acrylic Fiber Manufacturing Wastewater with a combined process of Fenton Oxidation, Two-stage UASB and SBR
中文摘要:       腈纶纤维是我国最早发展的化纤品种之一,由于其需求旺盛、产量高,因此产生的废水量也大。目前,腈纶工业废水的处理效果普遍不理想,达标排放率也很低,这主要是因其所含有机物浓度高,且具有生物毒性、难降解的特点,影响了生物处理效果。此外,腈纶废水中含有的含氮有机物在经过厌氧生物降解后会生成氨氮,其毒性虽然得以减轻,但是出水中氨氮含量增加。本研究采用Fenton氧化-两相UASB-SBR耦合工艺处理腈纶生产废水,考察了该工艺对腈纶废水的处理效果和运行稳定性。 综合考虑COD的去除和可生化性的提高,采用Fenton工艺预处理腈纶废水的最佳条件为:亚铁投加量300 mg/L,H2O2投加量500 mg/L,pH 3.0,反应时间2 h。在此条件下,COD去除率可达65%,废水可生化性由0.1上升到0.5左右,为后续的生化处理奠定了基础。此外,由于腈纶废水的pH值范围为3.0-3.8,采用Fenton工艺预处理不需要调节废水pH值,可大幅节省酸碱的投加量,具有较好的经济性。 采用两相UASB作为主体工艺,对腈纶废水经Fenton预处理后的出水进一步处理。实验采用中温消化(35 ± 0.5 oC),水力停留时间(HRT)在28到40小时之间波动。有机物和硫酸盐去除率随HRT的增加而显著提高。当HRT为38 h时,硫酸盐还原相和产甲烷相中的COD去除率分别达到了37%和29%,出水COD值为690 mg/L;而硫酸盐还原相中的硫酸盐去除率达到68%,系统总去除率保持在75%左右。在经过5周稳定运行后,成熟的颗粒污泥已经形成,其在硫酸盐还原相和产甲烷相中的最大粒径分别为5 mm和2 mm。与硫酸盐还原相相比,产甲烷相中的微生物种群更加丰富和多样化。就甲烷化而言,在腈纶废水处理过程中发挥重要作用的是Methanomethylovorans hollandica和Methanosphaerula palustris,它们可以较好地耐受腈纶废水中丙烯腈等毒性物质对微生物活性的抑制作用。硫酸盐还原菌的含量从硫酸盐还原相中的35%降低到产甲烷相中的9%;而产甲烷古菌的含量则从硫酸盐还原相中的28%升高到产甲烷相中的72%。 采用SBR工艺对经两相UASB工艺处理后的腈纶废水做进一步处理。由于氨氮的氧化发生在COD降解之后,若要取得较好的氨氮处理效果必须要有足够长的曝气时间。通过温度控制策略可以实现短程硝化。当温度为28 oC时,废水的亚硝化率在80%以上。较高浓度的游离氨对硝酸菌的抑制作用是此温度条件下短程硝化得以实现的主要原因。在常温条件下,通过pH控制策略同样可以实现腈纶废水的短程硝化。在pH 8.5时,最高亚硝化率可达62%。当曝气时间不大于22 h时,亚硝化率随曝气时间的增加而提高直至90%;但当曝气时间增至24 h后,NO2--N积累率回降至70%。过长的曝气时间引起的pH与游离氨含量的下降是造成亚硝化率降低的原因。
英文摘要:       As one of the most popular synthetic fibers, acrylic fiber has gained increasing production  and application. As a result, a large amount of acrylic fiber manufacturing wastewater has been produced. However, treatment of acrylic fiber manufacturing wastewater is difficult because it containes a great many toxic and biorefractory organic pollutants. Besides, organic nitrogen compounds, which are largely present in the wastewater, can be transformed to ammonia due to anaerobic digestion. Eutrophication may also occur if ammonia is not removed. In this work, a combined process of Fenton oxidation, two-stage UASB and SBR was exploited to treat acrylic fiber manufacturing wastewater. In terms of COD removal and biodegradability improvement, the optimal conditions for Fenton oxidation pretreatment were as follows: 300 mg/L Fe2+, 500 mg/L H2O2, pH 3.0, and reaction time 2 h. Under these conditions, the overall COD removal efficiency reached 65% and the value of BOD5/COD increased from 0.1 to 0.5, indicating improved biodegradability for further biological treatment. Besides, the raw manufacturing wastewater had a pH range of 3.0-3.8 that was suitable for Fenton oxidation process. Since pH adjustement was not required, which could greatly reduce the consumption of acid or base, this pretreatment process was cost-effective. In the two-stage up-flow anaerobic sludge bed (UASB) reactor, mesophilic operation (35 ± 0.5 oC) was performed with a hydraulic retention time (HRT) varying between 28 and 40 h. The results showed that the COD and sulfate removal efficiencies significantly increased with the increment of HRT. At the HRT of 38 h, COD removal efficiencies in the sulfate-reducing and methane-producing phases were 37% and 29%, respectively. The COD concentration in effluent was 690 mg/L. Sulfate removal efficiency in the sulfate-reducing phase was 68%, and the overall removal efficiency through the two-stage UASB reactor reached 75%. After 5 weeks’ steady-state operation, granular sludge was well formed in the reactor. The greatest sizes of granular sludge formed in the sulfate-reducing and methane-producing phases were 5 and 2 mm, respectively. Compared to sulfate-reducing phase, the microbial community in methane-producing phase was more diverse. In terms of methanogenesis, Methanomethylovorans hollandica and Methanosphaerula palustris played the most important role, because they showed more resistence to the toxicity of vinyl cyanide in acrylic fiber manufacturing wastewater. Sulfate-reducing bacteria (SRB) accounted for 35% and 9% of the total microorganism population in the sulfate-reducing and methane-producing phases, respectively; while in correspondence methane-producing archaea (MPA) accounted for 28% and 72%, respectively. Sequencing batch reactor (SBR) was used as advanced treatment of the effluent from the two-stage UASB reactor. The results showed that a long aeration time was necessary for ammonia removal since ammonia oxiadtion occurred after the removal of COD. The shortcut nitrification could be achieved by temperature regulation. The ratio of nitrosation was above 80% at 28 oC, because under this condition, the nitrite-oxidizing bacteria (NOB) were inhibited by a higher content of free ammonia (FA). Besides, the shortcut nitrification could also be achieved by pH regulation. The highest ratio of nitrosation, 62%, was achieved at pH 8.5. When the aeration time was no more than 22 h, the ratio of nitrosation kept increasing with aeration time untill 90%. However, as the HRT was furhter extended to 24 h, the nitrosation ratio dropped to 70% due to the decrease of pH and FA concentration after excessive aeration.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35071
Appears in Collections:环境水质学国家重点实验室_学位论文

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Recommended Citation:
李津. Fenton氧化-两相UASB-SBR耦合工艺处理腈纶废水实验研究[D]. 北京. 中国科学院研究生院. 2011.
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