【作者】 毕海；

【导师】 王伟； 张光明；

【作者基本信息】 清华大学 ， 土木工程， 2006， 硕士

【摘要】 本文针对当前水污染问题,特别是富营养化水体中的蓝藻水华问题,系统研究了紫外光抑制藻类生长的效果、规律和影响因素,进行了静态小试,中试及动态中试实验,并初步从机理上研究了紫外光辐照对藻细胞的形态,结构,生长规律所产生的影响。主要完成的内容有:(1)影响紫外抑藻效果的单因素分析,考察因素包括藻的种类,藻液厚度,辐照时间,辐照强度,辐照剂量等。(2)小试基础上的静态中试实验。(3)动态中试实验。(4)紫外辐照对藻的沉降性的影响;对藻细胞内含物的影响,包括辐照引起的叶绿素和藻蓝蛋白的含量及结构的变化。(5)不同技术的抑藻效果比较,包括投加药物和超声波辐照。(6)紫外抑藻技术实际应用的经济性分析。主要得出以下结论:(1)尺寸较小的球状藻类紫外抑制效果要好于尺寸较大的丝状藻类;藻液厚度的增加会引起紫外光传播过程中的快速耗散;随着辐照时间,强度的增加,抑藻效果随之增强并逐渐达到饱和,本实验条件下最优参数为辐照1 min,强度12.5 mW/cm2。(2)规模扩大后的静态及动态中试实验抑藻效果良好,在最优参数下能在7天内将藻的生长速率控制在0附近。而动态实验抑藻效果略好于静态实验。(3)紫外辐照会加强藻种群的沉降性能,而且紫外会对单个藻细胞产生全方位的伤害,经受辐照后,藻细胞断开、破裂,内含物溶出,无法进行正常的生理活动,并且其叶绿素a和藻蓝蛋白含量增加也受到抑制,光合作用色素结构也发生变化。(4)与其它抑藻技术相比,紫外抑藻具有更为长期的抑制效果。(5)紫外抑藻技术制水成本很低,中试实验条件下,正常运行每吨水只需要增加成本0.093元,而且只需在藻类爆发高峰期运行,每次运行后可保证7天内藻类生物量基本不增加,因此实际全年平均每吨水消耗成本要远低于0.093元。更多还原

【Abstract】 To control water pollution, especially cyanobacterial bloom in eutrophic water, the ultraviolet light inhibition of algae was studied including the effect, regularity and influencing factors. A series of static lab experiments and dynamic pilot tests were implemented. And preliminary research on irradiation influence by ultraviolet light to cellular form, structure and growth regularity were carried out. The researches mainly contain the following parts. Single factor analysis was investigated, and the factors included algae species, sample solution depth, exposure time, intensity and dose. Static and dynamic pilot tests were implemented basing on series of static lab experiments. Violet irradiation influence on the settleability of algae, intracellular matter including the chlorophyll and phycocyanin was studied. Difference irradiation effects by several algae inhibition technology including inhibitor releasing and ultrasound inhibition were compared. The cost was evaluated.The experiment results indicate: the spherical algae with smaller body could be inhibited more effectively than filaceous ones. The increase of algae sample solution depth could weaken inhibition effect severely because the energy dissipation of ultraviolet light during its transmission. Along the increase of exposure time and intensity, growth inhibition effect could be enhanced and tending to be saturated. The best conditions were, 2 cm of sample solution depth, 1 min of exposure time and 12.5 mW/cm2 of exposure intensity. The growth rate of algae could be limited to zero for seven days under the best condition in the static and dynamic pilot tests. And the dynamic test was more effective than static test of algae growth inhibition. The settleability of algae population could be enhanced by irradiation. The algae cell could be damaged completely with the disintegration of the cell, dissociation of cellular inclusion. The increase of the chlorophyll a and phycocyanin in algae cell could be inhibited and the structure of photosynthesis pigment could be also changed. Compared with other technology, ultraviolet irradiation could be more effective in longer time in algae inhibition. The cost of algae inhibition by ultraviolet was low, in the pilot test, the cost per ton water was 0.093 yuan when the ultraviolet device was operated regularly. When the algae concentration of water was not high, the device could be desuetuded. Even when the algae concentration is high, after one time irradiation the concentration could be reduced and limited to a low level for the next seven days. So the average cost per ton water was below 0.093 yuan.更多还原