CN102992432A

CN102992432A - Method and device for removing algae by applying micro-bubble air flotation of multiphase flow pump

Info

Publication number: CN102992432A
Application number: CN2012105577694A
Authority: CN
Inventors: 叶建锋; 李媛媛
Original assignee: 叶建锋; 李媛媛
Priority date: 2012-12-20
Filing date: 2012-12-20
Publication date: 2013-03-27

Abstract

The invention relates to a method for removing algae by applying micro-bubble air flotation of a multiphase flow pump. The method comprises the following step of releasing air dissolved water below a water body containing an algal layer, wherein the air dissolved water is formed in such a way that air and natural water simultaneously enter the multiphase flow pump under the action of negative pressure, dispersed air is cut many times by using a multistage impeller rotating at high speed in the multiphase flow pump, the air is instantly dissolved into the natural water in a highly dispersed state in a high pressure environment in the multiphase flow pump and rapidly saturated, and then is stabilized and contacted by an air dissolved tank for 50seconds-1hour, and the air dissolved water contains a great number of micro air bubbles with the diameter of small than 30mum, and the air dissolved water is released by decompressing to a position 0.3-1.2m away from the downside of the water body containing the algal layer. The method has the advantages of ideal air flotation effect achieved without adding a coagulant, no secondary pollution, no limitation of minimum water treatment quantity, simple process equipment, low device energy consumption and high system operation stability.

Description

Use the little air supporting of multiphase flow pump and remove method and the device thereof of algae

Technical field

The invention belongs to environmental technology field, be specifically related to a kind of device of the little air supporting removal of multiphase flow pump algae and method of removal algae thereof used.

Background technology

Algae pollution refers to algal bloom and the caused biological pollution of height cluster.Along with developing rapidly of industrial or agricultural, the excessive nutritive substances such as nitrogen phosphorus enter water body by all means, cause the Eutrophic Extent in lake (reservoir) to increasingly sharpen.Eutrophication water easily causes the algae burst breeding in summer, produces peculiar smell, destroys water landscape, has a strong impact on the safe for drinking of fresh water and the travel value in lake; Consume a large amount of dissolved oxygens in the algal grown process, can cause the death by suffocation of hydrocoles, the algae toxin of generation, the more direct health that threatens the mankind.The eutrophication problem in China lake (reservoir) is outstanding, China Environmental State Bulletin showed in 2011, the lake (reservoir) of nutritional status, slight eutrophic state and moderate eutrophic state accounts for respectively 46.2%, 46.1% and 7.7% in China, and the improvement of the algae pollution that eutrophication causes has become key subjects in China lake (reservoir) present stage and from now on quite long one period.

At present, common removal algae pollution technology can substantially be divided into machinery receipts algae method, Biological control method and add the chemical method three major types both at home and abroad.Mechanical process is remarkable as emergency processing means effect, but inefficiency, workload are large, are unsuitable for containing the higher waters of algae amount; Biological treatment can be removed algae and the pollutents such as nitrogen, phosphorus simultaneously, but the time cycle is long, can not realize in a short time efficient Pollution abatement; Add chemical method and have fast, the alga-killing rate advantages of higher of speed, but the process by product easily causes secondary pollution, affects the security of effluent quality.All there is the defective that is difficult to avoid to a certain extent in existing clearance technique for algae pollution, for tackling increasingly serious algae pollution problem, needs a kind of high-level efficiency of research and development, low input, free of contamination algae-removing method badly.

Tradition air flotation technology (bubble diameter 80～100 μ m) is the comparatively ripe water treatment method of widely a kind of technical process of China's current application, mainly for the treatment of relative density in the water less than or near 1 suspended impurity.Low density algae effect is removed with it in tradition air floatation alga removing aspect, water supply plant under the dosing coagulant condition better; And traditional air flotation technology is aspect processing natural water alga eruption, a small amount of imagination is also arranged: such as 00124828.6 1 kinds of ship-type air float algae-removing methods of the patent No., adopt the dissolved air type air-float method, comprise operations such as extracting former water, mixing, flocculation reaction, air supporting, emission treatment water, a whole set of flow process is installed on the ship to be moved, extract former water conservancy project order and emission treatment water conservancy project order is to carry out in same waters, after the dissolved air flotation operation, water after the partially disposed is back to the dissolved air flotation operation.And for example Chinese patent application number 200910196311.9 single air floatation alga removing ships that relate to are to treatment unit and the treatment process of large-area alga eruption of natural water body, and device is comprised of hull, air floatation component and dreg scraping unit spare.Air floatation component comprises fine bubble generating apparatus and micro-bubble releasing device; Dreg scraping unit spare comprises supporting cantilever, scrapes slag tipping bucket and dreg collecting slot.Air floatation form can adopt pressure air-dissolving tank By Bubble-floating Method or pressure air-dissolving pump By Bubble-floating Method.Concrete steps are: air floatation alga removing ship to overtake, the air supporting micro-bubble releasing device that is positioned at hull the place ahead begins to discharge micro-bubble, the microbubble that alga cells and natural water camber are disperseed adheres to mutually, makes it mutually assemble and float downward to the water surface in buoyancy; Hull in the algae-residue income algae-residue groove that the dreg scraping unit spare of fore comes up suspending, thereby reaches the purpose of removing Measures of Algae in Water Body in the process of moving.

Above-mentioned utilization tradition air-float technology is removed method and the device of algae, although considered that generally using air flotation technology carries out the development potentiality of algae removal on a large scale, but limit by traditional air-float technology equipment, produce bubble diameter large (about 80～100 μ m), cause and under the prerequisite of dosing coagulant not, remove algae effect extreme difference, if the removal efficient that does not add coagulating agent is probably in 5%;

The equipment flowsheet that adopts is more complicated also, and investment, running cost are higher.

In view of this, need to propose new technical solution.

Summary of the invention

The object of the invention is to, for present application air flotation technology remove the removal efficient that algae exists extremely low, need the problems such as dosing coagulant, equipment are comparatively complicated, operation is stable not, a kind of method of using the little air supporting removal of multiphase flow pump algae is proposed.

A further object of the present invention provides the device for the little air supporting removal of the application multiphase flow pump of aforesaid method algae.

The object of the invention is achieved through the following technical solutions: the invention provides a kind of method of using the little air supporting removal of multiphase flow pump algae, below containing the algal layer water body, discharge dissolved air water, wherein, described dissolved air water is by air and Natural Water, under suction function, enter simultaneously multiphase flow pump, after the multi-stage impeller of high speed rotating repeatedly cuts dispersion air in the multiphase flow pump, air is dissolved in Natural Water with highly dispersed state moment in multiphase flow pump inner high voltage environment and reaches capacity rapidly, again via the stable of dissolving 50s～1h with contact after, formation contains a large amount of diameters less than the dissolved air water of the micro-bubble of 30 μ m; Described dissolved air water is released in and contains algal layer water body below 0.3～1.2m decompression release dissolved air water, and the degree of depth is determined by algae thickness in the water body under water.The present invention need not add coagulating agent, its principle of removing algae is, contain a large amount of diameters in the dissolved air water less than the micro-bubble of 30 μ m, with after water body contains algal layer algae particle and mutually collides, contacts, adheres to each other, form bubble-algae grain interpolymer in the micro-bubble floating-upward process, floating to water surface forms algae-residue, thereby reach algae, moisture from purpose, simultaneously, before algae-residue is loose heavy, can utilize easily slag scraper or Algae harvester to remove.

On the such scheme basis, described dissolved air water flow control is at 400 L/h, and pressure is 0.7 Mpa, and air input is 0.2 ml/min, and dissolved air water amount and algae water yield ratio are 1.5～1.8.

The invention provides the little air supporting of above-mentioned application multiphase flow pump and remove the device of algae method, for generation of dissolved air water, be installed on movable type or fixed platform and the support, can freely dismantle, comprise inlet channel, intake ducting, multiphase flow pump, dissolving and outlet conduit, inlet channel and intake ducting are communicated with multiphase flow pump, and water, gas are fully mixed in multiphase flow pump, multiphase flow pump is communicated with dissolving, and the dissolved air water of generation is discharged from outlet conduit through dissolving.

The present invention uses the technology that multiphase flow pump is removed algae, give full play to the direct molten gas of multiphase flow pump and decompression jet and can stablize the generation diameter less than the advantage of 30 μ m microbubbles, processing unit is simple, also need not dosing coagulant, all can reach higher except algae efficient to high, medium and low different concentration of algae water bodys, and simple to operate, energy consumption is cheap, operational management is convenient, with this can realize to Hu Ku or general landscape water body algae efficient, remove fast.The efficient of little air floatation alga removing is different according to concentration of algae, removes algae efficient at 60%-80%, and concentration of algae is higher, and it is also higher to remove efficient.

On the such scheme basis, described multiphase flow pump can adopt rotating dynamical type multiphase flow pump or positive displacement multiphase flow pump, is single pump or many parallels connection of pumps.The model of multiphase flow pump and parameter determine and regulate according to the algae and water pollution condition of reality and to the requirement of flow, pressure, vapour-liquid ratio, when the processing water yield is larger, and can be by many parallels connection of pumps to realize effective algae removal.

On the such scheme basis, but described dissolving traverse, place vertically or tiltedly put, pattern has hollow type, sleeve to turn over streaming and spraying filler formula, wherein, it is porcelain Raschig ring, plastics drip water plate, stainless steel coil, structured packing and plastics cascade ring that the spraying filler formula is selected filler, and the dissolving material is copper, cast iron, cast steel or stainless steel etc.The tank body volume was determined according to the residence time

On the such scheme basis, the caliber of described inlet channel, intake ducting and outlet conduit determines that according to the size for connection of multiphase flow pump material is one or more combinations in PVC, UPVC, cast iron, Steel Concrete, iron bar, steel pipe, the bamboo cane.

The using method of present device, described dissolved air water are directly directly served as gas distribution pipe by outlet conduit and are discharged dissolved air water, process among a small circle waters, part; Perhaps, connect built-up type gas distribution element at outlet conduit, process waters on a large scale, thereby gas distribution when realizing the larger area waters, the coverage of gas distribution element is definite according to processing coverage of water size, multiphase flow pump power etc., is rectangle, square, circle, ellipse or fan-shaped etc.

Superiority of the present invention is:

⑴ utilize multiphase flow pump evenly to produce the microbubble (diameter is stable less than 30 μ m) of state of saturation, need not dosing coagulant, can reach desirable air flotation effect, and do not cause secondary pollution, without the restriction of the minimum treat water yield, be applicable to efficient, the fast removal of algae in most eutrophication natural waters;

⑵ processing unit is simple, need not to use the complicated air floatation component such as the air compressor in the traditional method, molten gas releasing device, Controlling System, make system's investment low, also be convenient to administer and maintain, and apparatus structure is compact, be easily installed in most of movable type or fixed platform and support, the organizational form freedom and flexibility;

⑶ plant energy consumption is low, can reach optimum energy-saving effect, and then reduces running expense;

⑷ system run all right is high, and the hardly impact of the fluctuations such as liquid body flow, vapour-liquid ratio is for condition has been created in the automatic control of technological process.

Description of drawings

Fig. 1 is the structural representation of apparatus of the present invention;

The algae-containing water air supporting result of the different high densitys of the identical air supporting amount of Fig. 2;

The algae-containing water air supporting result of concentration in the identical air supporting amount of Fig. 3 difference;

The algae-containing water air supporting result of the different lower concentrations of the identical air supporting amount of Fig. 4;

The algae-containing water air supporting result of the high, normal, basic different concns of the identical air supporting amount of Fig. 5;

The different air supporting water yield of the identical concentration of algae of Fig. 6 Chl-a clearance;

Number in the figure:

The 1--inlet channel; The 2--intake ducting;

The 3--multiphase flow pump; The 4--dissolving;

The 5--outlet conduit.

Embodiment

Further describe the present invention below by case study on implementation.

Shown in the structural representation of accompanying drawing 1 apparatus of the present invention, a kind of device of using the little air supporting removal of multiphase flow pump algae, for generation of dissolved air water, detachable being installed on movable type or fixed platform and the support, comprise inlet channel 1, intake ducting 2, multiphase flow pump 3, dissolving 4 and outlet conduit 5, inlet channel 1 and intake ducting 2 are communicated with multiphase flow pump 3, and multiphase flow pump 3 is communicated with dissolving 4, and the dissolved air water of generation is discharged from outlet conduit 5 through dissolving 4.Wherein:

Described multiphase flow pump 3 adopts rotating dynamical type multiphase flow pump or positive displacement multiphase flow pump, can adopt single pump or many parallels connection of pumps.

Described dissolving 4 traverses, place vertically or tiltedly put, pattern has hollow type, sleeve to turn over streaming and spraying filler formula, wherein, it is porcelain Raschig ring, plastics drip water plate, stainless steel coil, structured packing and plastics cascade ring that the spraying filler formula is selected filler, and the dissolving material is copper, cast iron, cast steel or stainless steel.

Described inlet channel 1, intake ducting 2 and outlet conduit 5 materials are one or more combinations in PVC, UPVC, cast iron, Steel Concrete, iron bar, steel pipe, the bamboo cane.

Utilize apparatus of the present invention to process and contain algae or alga eruption Hu Ku, inlet channel 1 in apparatus of the present invention, the pipeline opening of intake ducting 2 and outlet conduit 5 is positioned at natural water and contains the algal layer below, general 0.3～the 1.2m under water of the degree of depth under water, contain the water body that lower floor comparatively cleans in algae or the storehouse, alga eruption lake and pass through inlet channel 1, air is by intake ducting 2, entering simultaneously multiphase flow pump 3(model is EB3u, top hole pressure is 4.5bar), the liquid that contains a large amount of gas dissolvedes after the mixing enters the high 81cm of being of dissolving 4(, diameter is 11cm, the stainless steel iron flask), further dissolving is saturated in water to make air, and dissolved air water discharges from outlet conduit 5 decompressions.The micro-bubble come-up produces bubble diameter at 25～40 μ m, and ascent rate is 1.6～3.0m/h, and bubble distribution is even; Under the dissolved air water amount condition of 400L/h, process the blue algae water of high, medium and low different concns (160～3000 μ g/L), the clearance of its chlorophyll a is about 60～84%, the maximum climbing speed of algae-residue can reach 0.017cm/s and (water ratio is 97%) comparatively stablized in cohesion, it is long that the loose heavy time occurs, behind the algae-residue that in time strikes off come-up, can effectively realize efficient, fast removing to algae in the natural water.

The algae-containing water air supporting comparison test of the high, normal, basic different concns of identical air supporting amount:

The blue algae water of the high, medium and low concentration of Dianshan Lake is not passed through multiphase flow pump, directly enter air-flotation column, and tap water direct was connected multiphase flow pump, produce a large amount of dissolved air waters with this, then dissolved air water carries out air supporting through discharging into air-flotation column to algae-containing water.

See the algae-containing water air supporting result of the different high densitys of the identical air supporting amount of Fig. 2, in the higher situation of algae-containing water concentration (the algae water concentration is greater than 2000 μ g/L), it is nearly 80% that the highest clearance of Chl-a reaches, and minimum clearance is 58%, and average removal rate is 68.7%.And after the air supporting algae-residue and moisture from, water quality is limpid.

In the medium situation of algae-containing water concentration (500～2000 μ g/L), in identical air supporting water yield situation, the highest clearance of Chl-a is 70%, and minimum clearance is 63%, and average removal rate is 67%.

See the algae-containing water air supporting result of concentration in the identical air supporting amount of Fig. 3 difference, in the lower situation of algae-containing water concentration (less than 500 μ g/L), in identical air supporting water yield situation, the highest clearance of Chl-a is 63%, minimum clearance is 60%, and average removal rate is 62%.

See the algae-containing water air supporting result of the different lower concentrations of the identical air supporting amount of Fig. 4, blue algae water air supporting test through high, medium and low different concns, test-results is shown in the algae-containing water air supporting result of the high, normal, basic different concns of the identical air supporting amount of Fig. 5, can find out that this cover air-floating apparatus is 60～80% to the clearance scope of blue algae water Chl-a.

The comparison test of the different air supporting water yields of identical concentration of algae:

The dissolved air water amount is to affect what principal element of air supporting microbubble.The dissolved air water amount very little, the microbubble amount of generation is few, just can not be fully effectively contact adhesion with the algae particle water and float, the dissolved air water amount is too many, the microbubble of generation collides polymerization each other, is unfavorable for the adhesion of algae particle water, has wasted simultaneously energy.

By different dissolved air water amount tests, in the situation of identical concentration of algae, analyze the dissolved air water amount to the impact of Chl-a clearance.Size according to testing installation, having set the algae water yield in the air-flotation column is 40cm, on the basis of pre-stage test, four different dissolved air water amount gradients have been designed, dissolved air water amount and algae water yield ratio are 0.9,1.2,1.5,1.8, the dissolved air water flow control is at 400 L/ h, and pressure is 0.7 Mpa, and air input is 0.2 ml/min.Concrete operation condition is as shown in table 1.

Test-results as we know from the figure, in the constant situation of Chl-a concentration, increases the dissolved air water amount as shown in Figure 6, and the clearance of Chl-a raises gradually, and the highest clearance is about 80%, increases the dissolved air water amount again, and the amplitude that clearance increases is less.The dissolved air water amount that this testing installation is desirable and algae water yield proportional range are 100/40～112/40, and dissolved air water amount and algae water yield ratio are 1.5～1.8.

Claims

1. use the method that algae is removed in the little air supporting of multiphase flow pump for one kind, below containing the algal layer water body, discharge dissolved air water, wherein, described dissolved air water is by air and Natural Water, under suction function, enter simultaneously multiphase flow pump, after the multi-stage impeller of high speed rotating repeatedly cuts dispersion air in the multiphase flow pump, air is dissolved in Natural Water with highly dispersed state moment in multiphase flow pump inner high voltage environment and reaches capacity rapidly, again via the stable of dissolving 50s～1h with contact after, formation contains a large amount of diameters less than the dissolved air water of the micro-bubble of 30 μ m; Described dissolved air water is released in and contains algal layer water body below 0.3～1.2m decompression release dissolved air water.

2. the method for algae is removed in the little air supporting of application multiphase flow pump according to claim 1, it is characterized in that described dissolved air water flow control is at 400 L/h, pressure is 0.7 Mpa, air input is 0.2 ml/min, and dissolved air water amount and algae water yield ratio are 1.5～1.8.

3. the device of the method for algae is removed in the little air supporting of application multiphase flow pump according to claim 1 and 2, be installed on movable type or fixed platform and the support, it is characterized in that, comprise inlet channel, intake ducting, multiphase flow pump, dissolving and outlet conduit, inlet channel and intake ducting are communicated with multiphase flow pump, water, gas are fully mixed in multiphase flow pump, and multiphase flow pump is communicated with dissolving, and the dissolved air water of generation is discharged from outlet conduit through dissolving.

4. the device of algae method is removed in the little air supporting of application multiphase flow pump according to claim 3, it is characterized in that described multiphase flow pump adopts rotating dynamical type multiphase flow pump or positive displacement multiphase flow pump, is single pump or many parallels connection of pumps.

5. the device of algae method is removed in the little air supporting of application multiphase flow pump according to claim 3, it is characterized in that, but described dissolving traverse, place vertically or tiltedly put, pattern has hollow type, sleeve to turn over streaming and spraying filler formula, wherein, it is porcelain Raschig ring, plastics drip water plate, stainless steel coil, structured packing and plastics cascade ring that the spraying filler formula is selected filler, and the dissolving material is copper, cast iron, cast steel or stainless steel.

6. the device of the method for algae is removed in the little air supporting of application multiphase flow pump according to claim 3, it is characterized in that, the caliber of described inlet channel, intake ducting and outlet conduit determines that according to the size for connection of multiphase flow pump material is one or more combinations in PVC, UPVC, cast iron, Steel Concrete, iron bar, steel pipe, the bamboo cane.

7. utilize the little air supporting of each described application multiphase flow pump of claim 3 to 6 to remove the method for algae and the method for device thereof, it is characterized in that, in the described device, utilize outlet conduit to serve as gas distribution pipe and discharge dissolved air water, process among a small circle waters, part; Perhaps, connect built-up type gas distribution element at outlet conduit, process waters on a large scale, thus gas distribution when realizing the larger area waters, and the coverage of gas distribution element is rectangle, square, circle, ellipse or fan-shaped.