KR0174364B1 - Method and apparatus for removing algae - Google Patents

Abstract

In the present invention, the raw water containing a large amount of algae flows into the rapid mixing tank 2 through the raw milk feed pipe 8 and a certain amount of coagulant introduced by the metering pump 7 in the coagulating agent tank 6 is supplied to the agitator 4 And the fine flocs generated in the rapid mixing tank 2 are supplied to the plurality of baffle plates 5 alternately installed in the condensation tank 3, During aging, they are gathered together by a weak impact to form giant floc particles. The agglomerated and mixed water flows upward through the inlet pipe 10 of the flotation device 11, and ultrafine bubbles ejected through the nozzle 19 The sludge generated by the floated sludge is introduced into the floatation concentrator (13) by the sludge remover (21), and the floatation concentrator (13 ) The sludge is discharged to the surface by lowering the water content of the sludge with high water content and the lower treated water is returned to the raw water inlet (24) through the concentrating water pipe (24) And the concentrated sludge is sent to the dehydrator 14 through the sludge outlet pipe 25. The treated water from which the sludge has been removed from the floatation device 11 is sent to the sand and granular activated carbon filtration tank 28, The untreated material is removed from the apparatus so that the final treated water is supplied.

Description

Fixed algae removal method and apparatus

The present invention relates to a fixed algae removal method and apparatus therefor.

Generally, in a river, the growth of algae due to the influx of nutrients is not a big problem directly, and the lack of dissolved oxygen is a problem. On the other hand, unlike rivers, lakes are becoming a problem of eutrophication, which is the overproduction of algae due to the congestion of water bodies.

In the early days when the lake was formed, the nutrient concentrations were low and the production and consumption in the water system were balanced to maintain the nutrient status. However, as the concentration of nutrients gradually increased and the productivity of the lake increased over time, .

Eutrophication is a phenomenon that occurs when substances accumulate in the lake, such as carbon, nitrogen, and phosphorus, which will become nutrients for the breeding of birds. These nutrients are contained in the forests, as well as in the household wastewater and plant wastewater as well as in the detergents, agricultural fertilizers, livestock products and synthetic detergents. Thus, lakes with active human activities in the watershed are eutrophied at a faster rate than natural conditions. As nutrients continue to enter the lake in various forms and become over the lake's self-sufficiency, water pollution occurs gradually and this process is further promoted by stratification of the reservoir. Even if organic pollutants are decomposed and removed, minerals that will become nutrients can accumulate in the propagation of aquatic microorganisms. As a result, various kinds of birds will breed, and the degradation products of these birds will repeat the vicious cycle of being a nutrient of other birds.

Algae are eukaryotic organisms and collectively referred to as a variety of microorganisms that have chlorophyll that can be autotrophic and autotrophic. The characteristics of algae mainly found in freshwater are as follows.

Algae, which are the main problem in eutrophication, are cyanobacteria, which are very simple and similar in many ways to bacteria. Cyanobacteria are unicellular, have no flagellum, and chlorophyll is not in the chloroplast but distributed throughout the cell. In addition, since blue algae can fix nitrogen through air for cell synthesis, removal of nitrogen component in water does not significantly affect the growth of blue algae.

Green algae mainly live in fresh water and have single cell or multicellular cell structure. Green algae are distinguished from other algae in that chlorophyll and pigment are present in chloroplasts.

Euglenophyta is light green with a single cell and a flagella. The diatoms are mostly single cells and have a shell of silicic acid, and their sediments form diatomite.

These birds cause a variety of odors and flavors. Green algae smell and taste like fishy rot or rot, Diatoms smell like fishy smell and moldy smell and taste, and cyanobacteria smell like rotten or grassy smell and taste. Algae consume nutrients and zooplankton ingest algae. And they are decomposed to become a source of organic nitrogen and organic phosphorus, and it becomes a nutrient again.

In general, as the biomass of birds increases, the lake becomes turbid and aesthetically unpleasant. If the dominant species of algae turns into cyanobacteria, various toxic substances and unpleasant taste smell are generated. As the lake becomes eutrophic, the fluctuation of dissolved oxygen becomes severe, because the algae are photosynthetic during the day and the oxygen is supersaturated, but at night the algae breathes and consumes a lot of dissolved oxygen. The extreme fluctuations of dissolved oxygen are a major constraint on the aquatic ecosystem.

Eutrophic lakes fish survive only those species that can accommodate excessive concentrations of algae and severe dissolved oxygen variations. In general, the ecosystems of eutrophicated lakes are low in diversity and thus less stable.

The problem of water pollution in eutrophicated lakes is not due to eutrophication itself, but rather the eutrophication of lake water increases the primary productivity, which means that algal blooming is likely to occur. When algae are formed on a large scale on the surface of the lake, they prevent light from penetrating into the lake, inhibiting the photosynthesis of aquatic organisms and reducing dissolved oxygen in the water by preventing oxygen from dissolving in the water. In addition, when the algae formed on the surface of the lake are killed and sink into the deep water layer, the dissolved oxygen of the deep water layer is deficient due to the decomposition by the microorganisms, resulting in the anaerobic state.

In Korea, about 40% of the water sources are used as lake water including dams. In the case of water treatment plants using lake water as a water source, tap water is supplied due to clogging of the filtration membrane due to the occurrence of algae, deterioration of taste, And has suffered a great deal of damage. This phenomenon is caused by the eutrophication caused by the inflow of nutrients such as phosphorus and nitrogen into the stagnant water such as the lake, and the water temperature over 20 degrees Celsius is maintained for a long time, and a large amount of algae are breeded, and many rivers and lakes of the country periodically It is experiencing a bird-to-bird outbreak.

In the existing water treatment process, excess chlorine or ozone is administered to remove algae. However, chlorine disinfection induces disinfection byproducts including carcinogenic substances. In the case of ozone, it is effective in removing hobby substances. However, there is a limit to the removal of algae when the occurrence of algae occurs, and the installation and maintenance cost is too high, There are disadvantages. In addition, the process for directly separating algae can be separated during the sedimentation process after coagulation and mixing in the water treatment process. However, due to the nature of the algae floating itself, the repulsive action of the surface charge and the hydrophilic nature of the cell surface, It is difficult to perform the precipitation process.

In the existing water treatment process, chlorine or ozone treatment is performed to remove algae, but chlorine disinfection induces carcinogenic disinfection by-products. In case of ozone, it is effective to remove hobby materials, Installation maintenance cost is too high and the effect is not sustainable. In addition, algae have the problem that it is difficult to treat by the sedimentation process which is mainly used in domestic water treatment due to the characteristic of floating itself, the repulsive action of surface charge, and the hydrophilicity of the cell surface.

An object of the present invention is to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a method and apparatus for controlling flooding, The present invention also provides a method and an apparatus for solving the problems of the conventional precipitation process, as well as improving the processing efficiency and the economical efficiency.

In order to achieve the above-mentioned object, the present invention provides a method of controlling the flow of raw water, which contains a large amount of algae, into a rapid mixing tank through raw milk feed, and introducing a predetermined amount of coagulant (PAC; aluminum aluminum chloride, or aluminum sulfate) is rapidly mixed by an agitator, and the suspended particles of the suspended phase aggregate to form micro flocs.

The fine flocs generated in the rapid mixing tank are bundled with each other by weak impacts while passing through a plurality of alternately installed baffle plates in the coagulation tank to form macroporous flock particles, And ultrafine bubbles ejected through the nozzles located at the upper end are effectively adhered to the strong algae to induce them to the surface by lowering the density.

The sludge generated by the sludge floated in the upper part is sent to the batch type floatation concentrator by the scum removing device, and the sludge flowing into the floatation concentration device at regular intervals automatically closes the sludge inflow pipe when the water level reaches a certain level, The sludge is discharged to the concentrator's water surface while lowering the water content of the sludge having a high water content, and the lower treated water is sent to the raw milk inlet through the concentrator treatment water pipe. The concentrated sludge is sent to the dehydrator through the sludge outlet pipe.

The treated water from which the sludge has been removed in the above-mentioned floating device is sent to the sand and granular activated carbon filtration tank which is the final treatment process, and the untreated materials are removed from the floating and floating device to supply the final treated water.

When the head loss is increased due to the accumulation of suspended solids in the filtration tank, it is necessary to perform backwashing. By using pressurized water and air as the backwash water, it is possible to reduce the amount of backwash water more efficiently than the conventional backwash method.

FIG. 1 is a schematic view showing an overall configuration of the present invention. FIG.

FIG. 2 is a detailed schematic diagram of a flotation device and a concentrator part. FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

1: Enclosure 2: Rapid mixing tank

3: Condensation tank 4: Stirrer

5: Baffle plate 6: Coagulation tank

7: Quantitative Pump 8: Raw Milk Entry

9: pump 10,12,16,18,23,24,25,26,27: inlet pipe

11: Floating device 13: Condenser

14: Dehydrator 15: Circular tank

17: pressurizing device 19: nozzle

20: Baffle 21: Sludge can be there

22: hopper 28: granular activated carbon filtration tank

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

FIG. 1 is a system of a fixed algae removing apparatus according to the present invention. The housing 1 fixedly installed on the ground includes a rapid mixing tank 2 provided with an agitator 4 and a plurality of baffle plates 5, (3), raw water containing a large amount of algae is introduced into the rapid mixing tank (2) through the raw milk feed inlet (8) by the pump (9), and the coagulant A predetermined amount is supplied by the metering pump 7.

The baffle plate 5 is provided with a plurality of baffle plates 5 on the side of the baffle plate 5 in order to facilitate the floatation of fine flaps in the process of moving the water by the natural fluid flow, And the jig 5a is formed at intervals.

In such a configuration, the coagulant supplied to the raw water is rapidly mixed by the agitator 4, so that the suspended particles of the floating phase are agglomerated to form micro flocs, and the micro flocs generated in the rapid mixing tank 2 are condensed in the condensation tank 3 , They collide with each other due to the weak impact to form giant floc particles. This process of condensation depends on the degree of collision and its time. Particularly, in the case of the pressurized air floating method, there is no need to increase the strength or density of the floc as compared with the precipitation step, which is advantageous in that short condensation time and power consumption are small.

And a floatation device 11 for supplying untreated water through the untreated water inlet pipe 10 to the coagulation tank 3 so as to separate and remove the treated water and the algae from the floatation device 11 And a concentrator 13 for supplying sludge through the sludge inlet pipe 12 so as to re-separate the sludge having a high water content filtered by the concentrator 13, And a dehydrator (14).

Further, the floatation device 11 and the concentration device 13 are connected to the pressurizing device 17 so as to use pressurized water when separating the sludge.

2 shows a configuration of a floatation device and a concentration device. First, the floatation device 11 is connected to an untreated water inflow pipe 10 A sludge inlet pipe 16 having a hopper-shaped collection port 16a is provided in the upper portion of the untreated water inlet pipe 10 and a sludge inlet pipe 16 is provided on both sides of the upper end of the untreated water inlet pipe 10, A nozzle 19 is provided so as to inject pressurized water sent from the pressurizing device 17 through the pressurizing water pipe 18 so as to raise the baffle 20 to the outside of the nozzle 19, And a sludge remover 21 for removing the sludge that floats on the surface of the water in the upper part of the circular tank 15 and sending it to the collection port 16a.

The concentrator 13 has a hopper shape and receives the sludge through the sludge inlet pipe 16 on the hopper 22 and supplies pressurized water along the pressurized water pipe 23 to float the sludge when the sludge is re- The concentrated water pipe 24 and the concentrated sludge are sent to the dehydrator 14 so as to send the treated water back to the raw milk feed pipe 8 at the lower part of the hopper 22, Respectively.

The pressurizing device 17 is constituted by injecting air into the water and pressurizing the pressurized water into the pressurizing tube ADT 17a and connecting the pressurizing tube 17a to the compressor 17b and the return pump 17c, And is used by receiving the treated water through the treated milk infusion pipe 26.

In this configuration, when the flocculated and mixed water passing through the condensation tank 3 flows into the upper portion of the floating device 11 through the untreated water inlet pipe 10, the water is injected through the nozzle 19 located at the upper end, Of ultrafine bubbles are effectively attached to flood-resistant algae to induce floatation by lowering the density to separate and remove the treated water and algae.

By injecting ultrafine bubbles continuously into the flotation device, an ultrafine bubble filtration layer is formed which forms fine voids, which continuously rises, filtering out not only algae but also other fine particles. As a result, suspended solids and organic materials, Is effectively treated.

The sludge layer generated by the sludge floated in this manner is squeezed by the operation of the sludge remover 21 and sent to the hopper-shaped collection port 16a located at the center of the sludge removal unit 21, The sludge introduced into the concentrator 13 at regular intervals is automatically sent to the device 13 to automatically close the sludge inlet pipe when the water level reaches a certain level and automatically open the nozzle to pressurize the sludge, And the treated water in the lower part which has been floated to the apparatus water surface is sent to the raw milk inflow pipe 8 through the concentration water pipe 25 again. The concentrated sludge is sent to the dehydrator 14 through the sludge outlet pipe 24.

On the other hand, the treated water from which the sludge has been removed from the floating device (11) is provided with a sand and granular activated carbon filtration tank (28) connected to the treated water inflow inlet (27) to remove unprocessed substances in the crazy floating process. And also acts as a safety device in case of an accident.

In particular, the removal of the metabolites, such as the geosmin and 2-MIB, which cause aesthetic problems such as the taste and odor generated from algae, and finally the remaining trace contaminants are finely adsorbed and separated.

When the head loss is increased due to the accumulation of suspended solids in the filtration tank, the backwashing must be performed. By using the pressurized water and air of the pressurizing device 17 as the backwash water, the efficiency of the backwashing . At this time, the backwashing rate is 36-49 m ³ / m ² · hour, which causes the adsorption phase to expand to 25-50%. The backwashing time is less than 7 minutes and takes much less time than the conventional backwashing method.

15-30% of the number of end-processing is again conveyed by the conveying pump (17c) can be pressurized while being mixed in a pressure tube (17a) in the air pressure conditions of 4-5kg / cm ² by a pressurized air by a compressor (17b) By using the final treated water treated by the sand and granular activated carbon filtration tank, which is slightly different from the pressurized water conveying method of the conventional pressurized air floating method, as the conveying water, the conveying cost reduction effect and the treatment efficiency are improved due to the improvement of the conveying water quality And corrosion of the pressurizing tube ADT can be obtained. In addition, the pressurized water thus generated can be effectively used for various processes such as sludge concentration of the floatation concentrator and backwash water of the sand and granular activated carbon filtration tank, as well as removal of algae from the floatation device, thereby reducing the installation cost and maintenance cost have.

The final treated water produced by the process of the present invention shows almost 100% removal efficiency in the case of algae and is superior to 57-81% in the sedimentation process algae removal efficiency of the existing water treatment process. It can effectively control heavy metals, trace carcinogens harmful chemicals, volatile organic pollutants as well as taste and odor removal.

In the present invention, instead of the sedimentation process, which occupies a large part of the existing water treatment process, the use of a circular pressurized floatation device significantly reduces the installation area of about 10 times as much as the sedimentation process and not only the solid- (Average 40μm) bubbles are formed by dissolving air at high concentration under high concentration, so as to not only remove floatable algae but also remove contaminants such as suspended substances and heavy metals more effectively than existing precipitation processes Chemical oxidation can be expected, and volatile organic substances can be removed.

Claims (5)

And a condensation tank 3 in which a plurality of baffle plates 5 are alternately provided with a rapid mixing tank 2 in which a stirrer 4 is installed and a condensation tank 3 in which a plurality of baffle plates 5 are alternately arranged, (1) in which raw water is introduced through a water tank (8) and a certain amount of coagulant stored in the coagulant tank (6) is supplied by a metering pump (7) A floatation device 11 provided in the coagulation tank 3 to supply untreated water through an untreated water inflow pipe 10 to separate and remove algae and a sludge sludge having a high water content filtered by the floatation device 11 A dehydrator 14 for treating the sludge re-separated in the concentrating device 13 into a cake state, a floatation device 11 ) And a concentrator (13), a pressurizing device (17) provided to use pressurized water when separating the sludge, The treated water from which the sludge has been removed in the apparatus (11) is composed of a sand and granular activated carbon filtration tank (28) connected to the treated water inflow inlet (27) to remove unprocessed substances in the crazy floating process. Device. The floatation device (11) according to claim 1, characterized in that the untreated water inflow pipe (10) to which coagulated and mixed water is supplied via the coagulation tank (3) is vertically installed at the center of the circular tank (15) A sludge inlet pipe 16 having a hopper-shaped collection port 16a is provided in an upper portion of the inlet pipe 10 and a nozzle 19 is provided on both sides of an upper end of the untreated water inlet pipe 10 to inject pressurized water. A baffle 20 is installed on the outer side of the nozzle 19 to enhance the floating effect and the sludge floating on the surface of the circular tank 15 is removed and sent to the collection port 16a And a sludge remover (21). The hopper according to claim 1, wherein the concentration device (13) is connected to a nozzle (23a) connected to the pressurized water pipe (23) so as to float the sludge on the lower part of the hopper (22) And a sludge discharge pipe (25) are installed in the sludge discharge pipe (24). The stationary algae removing device according to claim 1, wherein the sand and granular activated carbon filtration tank (28) is backwashed by pressurized water of a pressurizing device (17). The raw water containing a large amount of algae flows into the rapid mixing tank 2 through the raw milk feed pipe 8 and a certain amount of coagulant introduced by the metering pump 7 in the coagulating agent tank 6 is stirred by the stirrer 4 The suspended particles of the floating phase are agglomerated to form fine flocs. The fine flocs generated in the rapid mixing tank 2 are weakly mixed with the weak flocs during passing through the plurality of baffle plates 5 alternately installed in the coagulation tank 3 The process of forming macroporous particles by collision with each other and the coagulated and mixed water are introduced into the upper part through the inflow pipe 10 of the flotation device 11 and ultrafine bubbles ejected through the nozzle 19 The sludge generated by floating sludge is guided to the water surface by effectively attaching to the strong algae to reduce the density, and the sludge produced by the sludge remover (21) is sent to the floatation concentrator (13) 13) As the sludge enters the water level, the sludge inlet pipe is automatically closed and the pressurized water is discharged, and the water content of the sludge having a high water content is lowered to float to the surface of the sludge, and the lower treated water is introduced again through the enrichment treatment water pipe (24) And the concentrated sludge is sent to the dehydrator 14 through the sludge outlet pipe 25. The treated water from which the sludge has been removed from the floating device 11 is sent to the sand and granular activated carbon filtration tank 18 And removing the untreated materials from the aspirating and floating apparatus to supply the final treated water.