CN103787526A - Method for removing blue-green algae by using microbubble hydrodynamic cavitation enhanced coagulation - Google Patents

Abstract

Translated fromChinese

本发明涉及一种利用微气泡水力空化强化混凝去除蓝藻的方法，包括如下步骤：（1）选用通用的微气泡水力空化发生装置；（2）将藻液放入所述微气泡水力空化发生装置的水箱中，开启水泵，开始水力空化作用，基于水力空化的机械效应和热效应，破坏细胞壁，杀灭藻体，同时超强氧化降解水中胞内及胞外分泌物，实现对水质的净化；（3）经过水力空化预处理后，再进行混凝过程，水力空化强化混凝效果。本发明首次公开利用微气泡水力空化技术去除藻类，相对其他除藻法如化学药剂法，更加高效、清洁，并且将水力空化技术与混凝沉淀相结合，提高除藻效率，降低混凝剂投加量。

The invention relates to a method for using micro-bubble hydraulic cavitation to strengthen coagulation to remove cyanobacteria, comprising the following steps: (1) selecting a general-purpose micro-bubble hydraulic cavitation generating device; (2) putting algae liquid into the micro-bubble hydraulic cavitation In the water tank of the cavitation generating device, turn on the water pump and start the hydraulic cavitation. Based on the mechanical and thermal effects of the hydraulic cavitation, the cell wall is destroyed, the algae are killed, and the intracellular and extracellular secretions in the water are degraded by super-strong oxidation to achieve Purification of water quality; (3) After hydraulic cavitation pretreatment, the coagulation process is carried out, and hydraulic cavitation strengthens the coagulation effect. The present invention discloses for the first time the use of micro-bubble hydraulic cavitation technology to remove algae, which is more efficient and cleaner than other algae removal methods such as chemical agent methods, and combines hydraulic cavitation technology with coagulation sedimentation to improve algae removal efficiency and reduce coagulation dose dosage.

Description

Translated fromChinese

利用微气泡水力空化强化混凝去除蓝藻的方法Method for removing cyanobacteria by using microbubble hydraulic cavitation to enhance coagulation

技术领域：Technical field:

本发明属于水处理技术领域，涉及利用水力空化过程中产生的机械效应、热效应、自由基效应等去除富营养化水体中蓝藻的方法。The invention belongs to the technical field of water treatment, and relates to a method for removing blue-green algae in eutrophic water bodies by utilizing mechanical effects, thermal effects, free radical effects and the like generated in a hydraulic cavitation process.

背景技术Background technique

水力空化现象是由流体流过一个收缩装置（如几何孔板）时产生的一种物理现象[1]。当液体流过孔板或其他空化器时，由于受到节流作用，流速剧增，压力骤减，当压力降至空化初生压（一般为相应温度下的饱和蒸汽压）时就会产生大量的空化微气泡[2]。微气泡在随液体流动过程中，遇到周围压力增大时，体积将急剧缩小或溃灭，溃灭过程发生于瞬间（微秒级），空化微气泡溃灭时将产生瞬时的局部高温（5000°C）、高压（50MPa以上），即形成所谓的“热点”，并能形成强烈的冲击波和速度大于400km/h的微射流[3]。此外，在空化过程中产生的微气泡爆破时，气液界面消失，周围环境剧烈改变产生的化学能促使大量羟基自由基生成[4]，羟基自由基具有超高的氧化还原电位。Hydrodynamic cavitation is a physical phenomenon that occurs when fluid flows through a constriction device such as a geometric orifice [1]. When the liquid flows through the orifice plate or other cavitators, due to throttling, the flow rate increases sharply and the pressure drops sharply. When the pressure drops to the cavitation incipient pressure (generally the saturated vapor pressure at the corresponding temperature), it will A large number of cavitation microbubbles [2]. When the microbubbles flow with the liquid, when the surrounding pressure increases, the volume will shrink or collapse sharply. The collapse process occurs in an instant (microsecond level). When the cavitation microbubbles collapse, instantaneous local high temperature will be generated. (5000°C) and high pressure (above 50MPa), the so-called "hot spots" are formed, and can form strong shock waves and micro jets with a speed greater than 400km/h[3]. In addition, when the microbubbles generated in the cavitation process explode, the gas-liquid interface disappears, and the chemical energy generated by the drastic change in the surrounding environment promotes the generation of a large number of hydroxyl radicals [4], which have an ultra-high redox potential.

目前我国70%以上的湖泊呈富营养状态，滇池、太湖和巢湖等都出现蓝藻泛滥的态势。由于藻类密度低，沉降效果差，给以湖泊水库为水源的饮用水处理带来诸多危害[5]，藻类的过度繁殖常常引起滤床堵塞、产生异嗅味，影响净水厂出水水质；当藻类极度繁殖时，即使增大混凝剂、助凝剂和消毒剂等投加量也不能使饮用水水质达标[6]，因此如何采用合理的措施强化饮用水中藻类的去除效率是给水处理面临的一大课题。混凝是水处理的基本单元操作，可以较好地去除藻类，但混凝剂的消耗量大大提高，因此引起费用上升、副产物增加等不利后果。At present, more than 70% of the lakes in my country are in a eutrophic state, and Dianchi Lake, Taihu Lake and Chaohu Lake are all in a state of cyanobacteria flooding. Due to the low density of algae and poor settling effect, it brings many hazards to the drinking water treatment with lakes and reservoirs as the water source [5]. When the algae multiply extremely, even if the dosage of coagulant, coagulant and disinfectant is increased, the drinking water quality cannot meet the standard[6]. a major problem to face. Coagulation is the basic unit operation of water treatment, which can remove algae well, but the consumption of coagulant is greatly increased, which causes adverse consequences such as increased costs and increased by-products.

水力空化技术具有高效、清洁、经济等优点，其必然在除藻领域有着广泛的应用前景，然而目前并未有人专门对水力空化除藻进行研究，也未有将水力空化技术与水厂现有工艺相结合的应用。Hydrodynamic cavitation technology has the advantages of high efficiency, cleanliness, and economy, and it must have broad application prospects in the field of algae removal. The application of the combination of the existing process of the factory.

参考文献references

[1]张晓冬,李志义,武君等.水力空化对化学反应的强化效应[J].化工学报,2005,56(2):262-265. [1] Zhang Xiaodong, Li Zhiyi, Wu Jun, etc. Strengthening Effect of Hydrodynamic Cavitation on Chemical Reaction[J]. Acta Chemical Industry, 2005,56(2):262-265. 

[2]沈壮志,林书玉.声场中水力空化泡的动力学特性[J].物理学报,2011,60(8):379-388. [2] Shen Zhuangzhi, Lin Shuyu. Dynamic characteristics of hydraulic cavitation bubbles in the sound field [J]. Acta Physica Sinica, 2011,60(8):379-388.

[3] 李志义,张晓冬,刘学武等.水力空化及其对化工过程的强化作用[J].化学工程,2004,32(4):27-29. [3] Li Zhiyi, Zhang Xiaodong, Liu Xuewu, etc. Hydrodynamic cavitation and its strengthening effect on chemical process[J]. Chemical Engineering, 2004,32(4):27-29. 

[4]张磊,刘平,刘春,等.微气泡及其在环境污染控制中的应用[J].河北工业科技,2011(1):61-65.[4] Zhang Lei, Liu Ping, Liu Chun, et al. Microbubbles and their application in environmental pollution control [J]. Hebei Industrial Science and Technology, 2011(1):61-65.

[5] 解军,贾坤. 水源水中藻类的危害及其去除技术[A]. 中国环境科学学会.2011中国环境科学学会学术年会论文集（第一卷）[C].中国环境科学学会:,2011:5.492-496[5] Xie Jun, Jia Kun. The Harm of Algae in Source Water and Its Removal Technology [A]. Chinese Society for Environmental Science. Proceedings of the 2011 Chinese Society for Environmental Science Academic Annual Conference (Volume 1) [C]. Chinese Society for Environmental Science :,2011:5.492-496

[6] 陈泉源,朱凌云,M.SALAS.高气泡表面积通量浮选柱气浮除藻的研究[J].环境污染治理技术与设备,2006(9):75-79。[6] Chen Quanyuan, Zhu Lingyun, M.SALAS. Research on Air Floatation and Algae Removal in High Bubble Surface Area Flux Flotation Column [J]. Environmental Pollution Control Technology and Equipment, 2006(9):75-79.

发明内容Contents of the invention

本发明的目的是提供一种针对富营养化水源的新型除藻技术，该工艺能够通过水力空化过程高效去除水体中藻类，并对藻体分泌物进行降解。通过水力空化预处理，可以强化混凝工艺的除藻效果，并减少化学药剂投加量。本发明通过大量实验确定了该工艺的最佳工况条件。The purpose of the present invention is to provide a novel algae removal technology for eutrophic water sources, which can efficiently remove algae in water bodies through hydraulic cavitation process and degrade algae secretions. Through hydraulic cavitation pretreatment, the algae removal effect of the coagulation process can be enhanced and the dosage of chemicals can be reduced. The present invention determines the optimal working conditions of the process through a large number of experiments.

为了达到以上目的，本发明给出的工艺技术方案是：In order to achieve the above object, the technological scheme provided by the present invention is:

一种利用微气泡水力空化强化混凝去除蓝藻的方法，其特征在于，包括如下步骤：A method for removing cyanobacteria by using micro-bubble hydraulic cavitation to strengthen coagulation, characterized in that it comprises the following steps:

（1）选用通用的能产生10um—200um直径气泡的微气泡水力空化发生装置；(1) Use a general-purpose microbubble hydraulic cavitation generator that can generate bubbles with a diameter of 10um-200um;

所述水力空化发生装置是由水箱、气液混合水泵、微气泡喷头等部件组成，其结构设计和工作原理在本领域属于已有技术，不是本发明技术方案对现有技术的贡献之处。The hydraulic cavitation generating device is composed of a water tank, a gas-liquid mixing pump, a micro-bubble nozzle and other components. Its structural design and working principle belong to the prior art in this field, and are not the contribution of the technical solution of the present invention to the prior art. .

（2）将藻液放入所述微气泡水力空化发生装置的水箱中，开启水泵，开始水力空化作用。基于水力空化的机械效应和热效应，作用在藻细胞上时，可以破坏细胞壁，从而杀灭藻体。同时，微气泡爆破时，气液界面突然消失，周围环境剧烈变化产生的化学能促使羟基自由基的生成，其超强氧化作用可降解水中正常条件下难以氧化分解的胞内及胞外分泌物，实现对水质的净化作用。(2) Put the algae liquid into the water tank of the microbubble hydraulic cavitation generating device, turn on the water pump, and start the hydraulic cavitation. Based on the mechanical and thermal effects of hydrodynamic cavitation, when it acts on algae cells, it can destroy the cell wall and kill the algae. At the same time, when the microbubbles burst, the gas-liquid interface suddenly disappears, and the chemical energy generated by the drastic changes in the surrounding environment promotes the generation of hydroxyl radicals, whose super-strong oxidation can degrade intracellular and extracellular secretions that are difficult to oxidize and decompose under normal conditions in water. Realize the purification effect on water quality.

（3）经过水力空化预处理后，再进行混凝过程，判断水力空化强化混凝的效果。(3) After hydraulic cavitation pretreatment, the coagulation process is carried out to judge the effect of hydraulic cavitation enhanced coagulation.

目前尚无采用水力空化与现有水处理工艺（包括混凝在内）相结合的研究，本发明技术方案的创新点在于，首次提出采用水力空化技术对“混凝”过程除藻的强化。本发明首次公开利用微气泡水力空化技术去除藻类，相对其他除藻法如化学药剂法，更加高效、清洁，并且将水力空化技术与混凝沉淀相结合，提高除藻效率，降低混凝剂投加量。At present, there is no research on the combination of hydraulic cavitation and existing water treatment processes (including coagulation). The innovation of the technical solution of the present invention is that it is the first time to propose the use of hydraulic cavitation technology to remove algae in the "coagulation" process. strengthen. The present invention discloses for the first time the use of micro-bubble hydraulic cavitation technology to remove algae, which is more efficient and cleaner than other algae removal methods such as chemical agent methods, and combines hydraulic cavitation technology with coagulation sedimentation to improve algae removal efficiency and reduce coagulation dose dosage.

附图说明Description of drawings

图1 为微气泡水力空化作用后，72h内藻密度变化规律；Figure 1 shows the variation of algae density within 72 hours after hydrodynamic cavitation of microbubbles;

图2 为微气泡水力空化作用后，3天内叶绿素变化规律；Figure 2 shows the change of chlorophyll within 3 days after microbubble hydrodynamic cavitation;

图3 为微气泡水力空化强化混凝与直接混凝的除藻效果对比。Figure 3 is a comparison of the algae removal effect of microbubble hydraulic cavitation enhanced coagulation and direct coagulation.

具体实施方式Detailed ways

以下结合附图和实施例对本发明技术方案作进一步说明。实施例1和2中，藻密度检测方法为分光光度法，例2中的混凝剂为聚合氯化铝（PAC），市售，氧化铝含量为46%。The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. In Examples 1 and 2, the algae density detection method is spectrophotometry, and the coagulant in Example 2 is polyaluminum chloride (PAC), commercially available, with an alumina content of 46%.

实施例1 （水力空化直接除藻）Example 1 (hydraulic cavitation directly removes algae)

本实施例实施步骤：The implementation steps of this embodiment:

（1）首先准备利用气液混合水泵产生微气泡的装置。(1) First prepare a device for generating microbubbles using a gas-liquid mixing pump.

（2）在水箱中加入藻密度约为2×109cel/L的藻液，开启装置，作用10min，然后将作用过的藻液与未经水力空化作用的空白对照组藻液一同置于光照培养箱正常培养，每隔12h小时测定藻密度，每天测定一次叶绿素含量。(2) Add algal liquid with an algae density of about 2×109 cel/L into the water tank, turn on the device, and act for 10 minutes, then place the treated algae liquid and the blank control group without hydrodynamic cavitation into light The incubator is normally cultivated, the density of algae is measured every 12 hours, and the chlorophyll content is measured once a day.

经过微气泡水力空化处理过后的藻液，在72h小时的观测时间内，藻密度持续下降，在72h后藻密度仅为原来的7.3%，去除率高达92.7%，而未经水力空化作用的对照样藻液藻密度基本未发生变化。After the microbubble hydraulic cavitation treatment, the algae density continued to decrease during the 72-hour observation period. After 72 hours, the algae density was only 7.3% of the original, and the removal rate was as high as 92.7%. Without hydrocavitation The algae density of the control algae liquid basically did not change.

 the

实施例2 （水力空化强化混凝除藻）Example 2 (hydraulic cavitation enhanced coagulation algae removal)

本实施例实施步骤：The implementation steps of this embodiment:

（1）首先准备利用气液混合水泵产生微气泡的装置。(1) First prepare a device for generating microbubbles using a gas-liquid mixing pump.

（2）在水箱中加入藻密度约为2×109cel/L的藻液，开启装置，作用一定时间，然后将作用过的藻液与空白对照样藻液分别进行混凝沉淀实验，混凝剂选用聚合氯化铝（PAC），投加量分别为0mg/L，1mg/l，2mg/L，3mg/L，5mg/L。混凝条件：150r·min-1快速搅拌2min，50 r·min-1慢速搅拌10min，在静沉30min后，于液面下2cm处取样并进行藻密度的测定。(2) Add algae liquid with an algae density of about 2×109 cel/L into the water tank, turn on the device, and act for a certain period of time, and then conduct coagulation and sedimentation experiments on the treated algae liquid and the blank control algae liquid respectively. Polyaluminum chloride (PAC) is selected, and the dosage is 0mg/L, 1mg/l, 2mg/L, 3mg/L, 5mg/L respectively. Coagulation conditions: rapid stirring at 150r·min-1 for 2min, slow stirring at 50r·min-1 for 10min, after static settling for 30min, sampling at 2cm below the liquid surface and determination of algae density.

为得到水力空化强化混凝的最佳工况，采取单因素变量法，依次考查水力空化作用时间、装置中水泵的真空度与出水压力、空气流量、pH值等因素对水力空化强化混凝效果的影响。In order to obtain the best working condition of hydraulic cavitation enhanced coagulation, the single factor variable method was adopted to examine the effects of hydraulic cavitation action time, vacuum degree of water pump in the device and water outlet pressure, air flow, pH value and other factors on hydraulic cavitation enhanced coagulation. Influence of coagulation effect.

混凝剂投加量相同时，水力空化预处理后的藻类去除率明显高于空白对照样。当混凝剂投加量为1mg/L时，空白样中只有36%的藻被去除，而经过水力空化5min后，去除率就达到49%，如果水力空化作用1h，去除率可达到65%。同样，要达到相同的藻类去除率，水力空化处理过的藻液所需混凝剂量要小于空白样。藻类去除率同为65%时，经1h空化作用样的混凝剂投加量仅为空白样的50%。When the dosage of coagulant is the same, the algae removal rate after hydraulic cavitation pretreatment is significantly higher than that of the blank control. When the dosage of coagulant is 1mg/L, only 36% of the algae in the blank sample are removed, and after 5 minutes of hydrodynamic cavitation, the removal rate reaches 49%. If the hydrodynamic cavitation is 1 hour, the removal rate can reach 65%. Similarly, to achieve the same algae removal rate, the amount of coagulant required for the hydrocavitation-treated algae liquid is smaller than that of the blank sample. When the algae removal rate is the same as 65%, the coagulant dosage of the sample after 1h cavitation is only 50% of the blank sample.

综合考虑藻类的去除效果、经济性和管理简便等因素，微气泡水力空化强化混凝除藻的最优工况为：水力空化时间为10min，水泵真空度为0.03MPa，水泵出口压力为0.4MPa ,空气流量为0.5~0.8 L·min-1，最适pH为8。Considering the algae removal effect, economy, and easy management, the optimal working conditions for microbubble hydraulic cavitation enhanced coagulation algae removal are as follows: the hydraulic cavitation time is 10 minutes, the vacuum degree of the water pump is 0.03 MPa, and the outlet pressure of the water pump is 0.4MPa, the air flow rate is 0.5~0.8 L·min-1, and the optimum pH is 8.

图1 为本实施例2微气泡水力空化作用后，72h内藻密度变化规律。Fig. 1 is the changing law of algae density within 72 hours after microbubble hydrodynamic cavitation in Example 2.

图2 为本实施例2微气泡水力空化作用后，3天内叶绿素变化规律。Fig. 2 is after the hydraulic cavitation of the microbubbles of thepresent embodiment 2, the change rule of chlorophyll in 3 days.

图3 为本实施例2微气泡水力空化强化混凝与直接混凝的除藻效果对比。Figure 3 is a comparison of the algae removal effect between microbubble hydraulic cavitation enhanced coagulation and direct coagulation in Example 2.

Claims (1)

Translated fromChinese

1.一种利用微气泡水力空化强化混凝去除蓝藻的方法，其特征在于，包括如下步骤：1. A method utilizing microbubble hydraulic cavitation to strengthen coagulation to remove blue-green algae, is characterized in that, comprises the steps:（1）选用通用的微气泡水力空化发生装置；(1) Select a general-purpose microbubble hydraulic cavitation generating device;（2）将藻液放入所述微气泡水力空化发生装置的水箱中，开启水泵，开始水力空化作用，基于水力空化的机械效应和热效应，破坏细胞壁，杀灭藻体，同时超强氧化降解水中胞内及胞外分泌物，实现对水质的净化；(2) Put the algae liquid into the water tank of the microbubble hydraulic cavitation generating device, turn on the water pump, and start the hydraulic cavitation. Based on the mechanical and thermal effects of the hydraulic cavitation, the cell wall is destroyed, the algae are killed, and the Strong oxidation degrades intracellular and extracellular secretions in water to achieve water purification;（3）经过水力空化预处理后，再进行混凝过程，水力空化强化混凝效果。(3) After the hydraulic cavitation pretreatment, the coagulation process is carried out, and the hydraulic cavitation strengthens the coagulation effect.

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