【作者】 杨再荣；

【导师】 张维；

【作者基本信息】 贵州师范大学 ， 环境科学， 2009， 硕士

【摘要】 水体富营养化已成为全球水体的主要病症,蓝藻水华是水体富营养化的主要环境灾害,我国各大湖泊水库已相继检测出了微囊藻毒素（Microcystins,MC）。红枫湖作为贵阳市主要饮用水水源地,自1996年发生水华以来就已经显现出湖库富营养化状况。2000年10月贵州省环科院中日合作研究项目曾对红枫湖微囊藻毒素MC-LR作过初步监测,但至今为止,国内还没有学者对深水湖库微囊藻毒素开展过全面的调查研究,对以深水湖库作为供水水源的自来水厂各工艺段对微囊藻毒素的去除也尚未开展相关研究。本论文在对微囊藻毒素提取、富集、检测方法进行深入探索的基础上,对深水湖库红枫湖和贵阳市西郊水厂常规水处理各个工艺段中微囊藻毒素的变化进行了研究,并对微囊藻毒素的强化去除技术进行了实验探索。研究得出如下主要结论:1.2008年6-12月对红枫湖中微囊藻毒素用高效液相色谱和酶联免疫的方法进行分析研究,结果表明,藻毒素在湖库中变化趋势和藻类生长繁殖的变化趋势有相同之处,均表现为夏、秋季高,但藻毒素含量的峰值比藻类生物量的峰值略有滞后。微囊藻毒素在表层水中以胞内藻毒素为主,在深层水中以胞外藻毒素为主。夏季红枫湖水体分层稳定,阻碍了水体在垂直方向的对流交换,藻和藻毒素在不同的水深有明显的浓度梯度分布。研究结果证实,深层取水可在很大程度上避开蓝藻水华带来的影响。2.自来水厂常规处理工艺对微囊藻毒素的去除能力有限,对总藻毒素的去除率为30%,对胞外藻毒素的去除率为7.9%,对胞内藻毒素的去除率为89.6%。对于胞外藻毒素,水处理工艺中氯化消毒段的去除率最高;对于胞内藻毒素,水处理工艺中混凝过滤段的去除率最高。因此,在自来水厂水处理中,当水中藻毒素以胞外藻毒素为主要形态时,处理措施应以氧化为主;而当水中藻毒素以胞内藻毒素为主要形态时,处理措施应以强化混凝除藻为主。3.高锰酸钾对微囊藻毒素的氧化是准一级反应,藻毒素MC-RR的半降解时间(t_1/2)为7.15 min,藻毒素MC-LR的半降解时间(t_1/2)为12.16min;溶液中COD_Mn为2和4mg/L时对藻毒素的去除速度基本没有影响,但藻毒素的去除率降低7%—11%;高锰酸钾对藻毒素的去除兼有氧化和吸附的共同作用,新生态二氧化锰对藻毒素有很强的去除能力。4.活性炭吸附微囊藻毒素在30min内完成快速吸附,45min之后对藻毒素的吸附速度逐渐变缓;粉末活性炭投加量为100mg/L时,对藻毒素的去除率为40%左右,粉末活性炭投加量为300mg/L时,藻毒素的去除率达71%以上。实验表明:低投加量的粉末活性炭对藻毒素的去除有限。5.对于以溶解性藻毒素为主的水源水,在水中初始胞外藻毒素（EMC）为2、5、10μg/L时,如对应的高锰酸钾投加量分别为0.5、0.8、1mg/L,聚合氯化铝的投加量为10mg/L的条件下,EMC的残留量分别为:0.06、0.12、0.25μg/L,加上自来水厂后加氯的消毒工艺,能保证出水的EMC在0.2μg/L以下,降低了MC长期暴露促肿瘤的风险。对于以胞内藻毒素为主的水源水,化学氧化+活性炭+混凝工艺能在很大程度上提高藻的去除率,强化去除大部分的胞内藻毒素,减少了水中藻毒素的含量。更多还原

【Abstract】 Eutrophication has become the main disease of water body in the world. Cyanobacterial blooms are the major environment disasters. Microcystins （MC） have also been examined in many lakes and reservoirs in China nowadays. Hongfeng Lake as the main drinking water source of Guiyang, it has appeared eutrophication since cyanobacterial blooms was found in 1996. With support of Sino-Japanese Cooperation Project, MC had been investigated primaryly in Hongfeng Lake in 2000. So far, no comprehensive investigation and study on MC in the depth lakes and reservoirs was done, neither did on the removal of MC on the conventional water treatment processes in waterworks which water supply from depth lakes and reservoirs. Based on the study of MC extraction, enrichment and analytical method, the variation and the removal method and it’s strengthen removal technologies of microcystins in water source and waterworks were studied in this paper. The main conclusions achieved as follows:1. From June to December, 2008, the method of high performance liquid chromatography （HPLC） and enzyme-limited immunosorbent assay （Elisa） were used to examine MC in Hongfeng Lake. The results showed that the tendency of MC was the same as that of algaes growth in lake. It displayed higher in summer, then autumn and winter, but the peak content of MC was a little bit latter than the peak of algae biomass. The intracellular microcystins （IMC） was the main morphological characters in surface water and the extracellular microcystins （EMC） was the main in depth water. Water temperature was stratified in summer, which would prevent the convection in vertical. It was obvious that there were concentration gradient distribution of algae and MC in different depth. Water supply from deep lake could avoid the hazard of cyanobacterial blooms greatly.2. It was inefficient to removal MC by conventional water treatment processes. Only 30% of total microcystins （TMC）, 7.9% of EMC and 89.6% of IMC could be removed. The experiment results showed that the EMC was effective removed by chlorination, and the IMC was higherly removed by coagulation sedimentation and filtration. So, when the EMC was the main morphological characters, it could be effectively removed by the main treatment process of oxidation. When the IMC was the main morphological characters, it could be effectively removed by the main treatment process of coagulation sedimentation.3. Comparison of the degradation of MC by potassium permanganate （KMnO₄） in different condition, it was found that the degradation process was with pseud-first-order reaction kinetics. The reaction half lives (t_1/2) for MC-RR and MC-LR were 7.15min and 12.16min, respectively. The removal velocity of MC was not influenced when COD_Mn was 2 or 4mg/L, but removal rata reduced about 7-11%. MC was removed with the cooperative effection of oxidation and adsorption of KMnO₄. Fresh manganese dioxide could remove the MC effectively.4. MC was adsorbed quickly by Powder activated carbon （PAC） within 30min. However, adsorption became slowly after 45min. About 40% of MC was removed when PAC was 100mg/L, and over 71% was removed while PAC was 300mg/L. The results showed that MC could not be removed effectively with low concentration of PAC.5. Results also showed that residual EMC were 0.06, 0.12, 0.25μg/L when EMC initial concentration were 2, 5, 10μg/L and KMnO₄ were 0.5, 0.8, 1.0mg/L, polyaluminium chloride was 10mg/L respectively. With chlorine disinfection in the processes of waterworks, it could ensure that the MC was less than 0.2μg/L in drinking water, this reduce the risk of promoting tumor under continuous exposure to low content MC. When the IMC was the main morphological characters, the combined processes of pre-oxidation of KMnO₄ + PAC adsorption + coagulation sedimentation could enhance the removal effection of algae, it could reduce the MC content in water effectively.更多还原