超声波强化混凝沉淀安全除藻水处理试验研究

发布时间：2018-06-07 23:46

本文选题：藻类 + 超声波　；参考：《扬州大学》2014年硕士论文

【摘要】：水体富营养已成为全球性的水环境问题,湖泊水库等水源地藻类过渡繁殖,严重影响了城市的供水,威胁供水安全。目前水厂中采用的除藻方法,在工艺的经济性、安全性和除藻的效率方面都存在着弊端,已经不能满足城市供水的需求和要求,以及人们对饮用水水质的要求。随着超声波技术和声化学的不断推广和发展,将超声波技术用于除藻抑藻方面日益受到重视,超声除藻抑藻技术具有清洁、反应条件温和、高效和速度快等显著特点,所以在藻类控制领域有着广阔的应用前景。本研究探究超声强化混凝沉淀除藻的效果以及其安全性,找出适当的频率、功率以及超声辐射的时间能够安全有效的去除藻类,保障供水安全。主要结论有以下几点：(1)一定频率一定功率的超声波短时间辐射含藻水样,然后进行混凝沉淀可以去除大量藻类,超声波强化混凝除藻技术除藻效果明显。频率20KHz、强度10档、8档、6档、5档、4档的超声波作用20s；频率40KHz、强度10档和8档的超声波作用15s,强度5档和6档的超声波作用20s,强度3档超声波作用60s；频率68KHz、强度10档、8档和6档的超声波作用10s,强度5档和4档超声波作用15s,强度3档超声波作用50s；频率80KHz、强度10档、8档、6档、5档和4档的超声波作用10s；频率120KHz、强度10档、8档、6档、5档、4档和3档的超声波作用10s后,再进行混凝沉淀都能达到良好的除藻效果,沉淀水浊度小于1NTU,叶绿素a浓度小于1μg·L-1,藻类去除率98%以上。(2)相同输入功率时,超声波频率越高,除藻效果越好。(3)随着水深的增加超声波除藻的效果变差,在15cm水深范围内68KHz和120KHz的10档功率除藻效果受水深的影响较小,其余受水深影响较大。随着水深的增加需要辐射更长的时间才能达到良好的除藻效果。所以超声波强化混凝除藻的效果,不仅和超声波的频率、强度和辐射时间有关,同时也受到水量水深的影响。当水量和水深增加时,增加超声波辐射的时间可以保证较好的除藻效果。(4)超声波辐射后藻毒素有一定量的增加,频率20-120KHz、强度3-10档超声波作用时间10s以内,藻毒素的增长率较小低于5%,并且都远低于WHO(世界卫生组织)推荐的饮用水水源中MC-LR的安全限值是1.0μg/L。短时间超声波作用后,水中DOC净减少,随着超声波作用时间延长,水中DOC浓度增加。频率68-120KHz的超声波作用10s以内,既能取得较好的除藻效果,又具有较高的安全性。(5)短时间的超声波辐射后混凝沉淀除藻效果明显并且安全,是一种经济环保的除藻技术,具有巨大的发展潜力。
[Abstract]:Eutrophication of water body has become a global water environment problem. Algae propagation in lakes and reservoirs has seriously affected urban water supply and threatened the safety of water supply. At present, the algal removal methods used in water plants have some disadvantages in the aspects of process economy, safety and efficiency, which can not meet the demand and requirement of urban water supply and the requirement of drinking water quality. With the popularization and development of ultrasonic technology and sonochemistry, more and more attention has been paid to the application of ultrasonic technology in algae removal and algal inhibition. Ultrasonic algal removal and algal suppression technology has the characteristics of clean, mild reaction conditions, high efficiency and high speed. So it has a broad application prospect in the field of algae control. The purpose of this study was to investigate the effect and safety of ultrasonic enhanced coagulation precipitation in algae removal, to find out the appropriate frequency, power and time of ultrasonic radiation to remove algae safely and effectively, and to ensure the safety of water supply. The main conclusions are as follows: 1) Ultrasonic wave with a certain frequency and a certain power for a short time to radiate algae-containing water, then coagulating and precipitating can remove a large number of algae, and the effect of ultrasonic enhanced coagulation and algal removal technology is obvious. Frequency 20 kHz, intensity 10, 8, 6, 6, 5, 4, 20 s; frequency 40 kHz, intensity 10 and 8 15 s; intensity 5 and 6, 20 s; intensity 3, 60 s; frequency 68 kHz, intensity 10 The ultrasonic action of 8 and 6 is 10s, the intensity of 5 and 4 is 15s, the intensity of 3 is 50 s; the frequency of 80kHz, the intensity of 10, 8, 6, 6, 5 and 4; the frequency of 120 kHz, the intensity of 10 / 8 / 8 / 6 / 6 / 5; the frequency of 80 KHz, the intensity of 10 / 8 / 6 / 6 / 5; the frequency of 120 KHz, the intensity of 10 / 8 / 8 / 6 / 5 After 10 seconds of ultrasonic wave in 4 and 3 stages, The higher the ultrasonic frequency is, the higher the ultrasonic frequency is when the turbidity of precipitated water is less than 1NTU, the concentration of chlorophyll a is less than 1 渭 g / L ~ (-1), and the removal rate of algae is over 98%. The better the algal removal effect is, the worse the effect of ultrasonic wave removal becomes with the increase of water depth. The effect of 10 stage power of 68kHz and 120kHz in the 15cm water depth range is less affected by the water depth, while the others are more affected by the water depth. With the increase of water depth, it takes longer radiation to achieve good algal removal effect. Therefore, the effect of ultrasonic enhanced coagulation is not only related to the frequency, intensity and radiation time of ultrasonic wave, but also affected by water depth. When the amount of water and water depth increases, the time of increasing ultrasonic radiation can guarantee a better algal removal effect. (4) after ultrasonic radiation, the algal toxin has a certain amount of increase, the frequency is 20-120 KHz, and the intensity of 3-10 ultrasonic wave is less than 10 seconds. The growth rate of algal toxin is lower than 5%, and the safety limit of MC-LR in drinking water sources recommended by WHO is 1.0 渭 g 路L ~ (-1) 路L ~ (-1). After a short period of ultrasonic treatment, the net DOC in water decreased, and the concentration of DOC in water increased with the prolongation of ultrasonic time. The ultrasonic wave with frequency of 68-120kHz can not only obtain better algal removal effect, but also have higher safety. 5) the coagulant precipitation after short time ultrasonic radiation has obvious and safe removal effect. It is an economical and environmental protection algal removal technology. There is great potential for development.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU991.2

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