聚合氯化铝铁高效低破损去除蓝藻细胞

发布时间：2018-03-08 17:09

  本文选题：聚合氯化铝铁　切入点：含藻絮体堆置　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：人类活动使自然水体富营养化日益严重,蓝藻水华暴发频繁且范围扩大,饮用水源也受到蓝藻水华的威胁,饮用水安全问题越来越受到关注。水华期间大量的藻细胞和其产生的有毒代谢产物,使水体水质急剧恶化,威胁着人类的生命健康。铜绿微囊藻是暴发蓝藻水华水体中常见的重要优势藻种,也是毒性最大的微囊藻毒素的主要产毒藻种。大部分的微囊藻毒素集中在细胞内部,因此,饮用水厂在处理高藻水时,把蓝藻细胞完整无破损去除具有重要意义。混凝沉淀是饮用水厂常规生产的核心工艺,能有效的去除水中的蓝藻细胞,但需要关注混凝过程对蓝藻细胞完整性的影响。本文采用聚合氯化铝铁(PAFC)混凝剂去除模拟原水中的高密度蓝藻细胞,考察了混凝的最优条件,及在最优混凝条件下混凝过程和含藻絮体堆置过程对蓝藻细胞完整性的影响。通过扫描电镜和荧光显微镜照片,胞外藻毒素变化和三维荧光矩阵光谱,共同评估蓝藻细胞破损情况。本文还考察了含藻絮体中微囊藻毒素的厌氧降解条件,避免含藻絮体释放微囊藻毒素造成二次污染。主要的研究结果：(1)处理模拟水华状态含藻细胞浓度约为2×106 cells/mL的高藻水,混凝条件优化结果是：PAFC剂量15 mg/L；快搅速度250 r/min,时间1 min慢搅速度40 r/min,时间20 min；静置沉淀时间20 min,蓝藻细胞去除率达99%。(2)混凝剂投加量、快搅速度、慢搅速度和慢搅时间对蓝藻细胞去除率有较大影响,快搅时间在本实验设置的范围内对蓝藻细胞去除率影响不明显。(3)混凝沉淀后,蓝藻细胞被完整的从模拟水样中去除,转移到了絮体之中。机械搅拌和最优剂量PAFC的投加不会造成蓝藻细胞明显的破损。(4)含藻絮体在堆置的12 d内,胞外微囊藻毒素浓度较低,并且从扫描电镜照片可以直观看出蓝藻细胞没有发生明显破损。但是蓝藻细胞正常生长状态被抑制,减少了向胞外释放有机物质。(5)含藻絮体通过厌氧处理,在初始pH=8,温度为35℃时,微囊藻毒素在第6d的降解率达到99%,浓度为1.16μg/L。含藻絮体中微囊藻毒素得到有效降解。
[Abstract]:Human activities make natural water eutrophication more and more serious, cyanobacteria Shui Hua outbreaks frequently and the scope is expanded, drinking water sources are also threatened by cyanobacteria Shui Hua. More and more attention has been paid to the safety of drinking water. During Shui Hua's period, a large number of algae cells and their toxic metabolites caused the water quality to deteriorate sharply. Microcystis aeruginosa is an important dominant algae species in the water body of cyanobacteria Shui Hua, and is also the main toxic algal species of microcystins. Most of the microcystins are concentrated in the cells, so, It is very important for drinking water plant to remove cyanobacteria cells completely and without damage. Coagulation and sedimentation is the core process in drinking water plant, which can effectively remove cyanobacteria cells from drinking water. However, the effect of coagulation process on the cell integrity of cyanobacteria should be concerned. In this paper, polyaluminum ferric chloride coagulant was used to remove high density cyanobacteria cells from simulated raw water, and the optimum conditions of coagulation were investigated. The effects of coagulation process and algal flocs stacking process on the integrity of cyanobacteria cells under optimal coagulation conditions were studied. The changes of extracellular algal toxins and three dimensional fluorescence matrix spectra were obtained by scanning electron microscopy and fluorescence microscopy. The condition of anaerobic degradation of microcystins in algae flocs was also investigated. Microcystins released from algal flocs could not cause secondary pollution. The main research result was: 1) treatment of high algal water with simulated Shui Hua cell concentration of about 2 脳 10 ~ 6 cells/mL. The optimization results of coagulation conditions are: 1: PAFC dosage 15 mg / L; fast stirring speed 250 r / min, time 1 min slow stirring speed 40 r / min, time 20 mins; static sedimentation time 20 mins; removal rate of cyanobacteria cells up to 99.2%) coagulant dosage, fast stirring rate. Slow stirring rate and slow stirring time had a great effect on the removal rate of cyanobacteria cells. The effect of fast stirring time on the removal rate of cyanobacteria cells was not obvious in the range of this experiment. After coagulation and sedimentation, the cyanobacteria cells were completely removed from the simulated water samples. It was transferred to the floc. Mechanical agitation and optimal dosage of PAFC did not cause obvious damage of cyanobacteria cells. (4) the concentration of extracellular microcystins was lower within 12 days after the accumulation of algal flocs. But the normal growth state of cyanobacteria cells was inhibited, which reduced the release of organic matter. 5) the algal flocs were treated by anaerobic treatment. At the initial pH of 8 and temperature of 35 鈩，

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