KR20230144289A - Method of purifying lake water - Google Patents

Abstract

The present invention relates to a method for purifying the water quality of a lake, and more specifically, a step (S10) of spraying a microbial fermentation liquid onto the upper part of a green algae treatment area or an odor treatment area using a spray means; A step (S20) in which microbubbles are mixed with the microbial fermentation liquid supplied from the microbial injection unit in a mixer to produce a mixed liquid; Injecting the mixed liquid into the lower part of the treated water area (S30); After the step S30, a step (S40) of measuring the odor removal rate and the change rate of the bacterial mass per unit volume of the strain contained in the microbial fermentation broth for each specific time period; A step (S50) of selecting a strain whose bacterial mass per unit volume of the strain decreases as a strain to be added during the time period when the measured odor removal rate decreases; And when there are a plurality of strains to be additionally introduced, the ratio of the bacterial mass change rate to the appeal odor removal rate is calculated for each strain, and the plurality of strains to be additionally introduced are mixed and introduced according to the calculated ratio (S60) ); characterized in that it includes.

Description

Method of purifying lake water}

The present invention relates to a method for purifying the water quality of a lake, and more specifically, to spray a highly active microbial fermentation solution for controlling green algae and then injecting a mixture of nano/micro bubbles and microorganisms into the lower part of the treated water area to purify the water produced in the lake. It relates to a method of purifying the water quality of lakes that can remove green algae and bad odors.

In general, a lake refers to a water system in which water flowing into a certain space stays for a certain period of time, and is classified into lakes, swamps, marshes, wetlands, etc. In the beginning when the lake is created, the concentration of nutrients is low and production and consumption within the water system are balanced, maintaining a oligotrophic state, but over time, the concentration of nutrients gradually increases depending on the isolated environment, and algae proliferates. When this becomes excessive, a process of eutrophication occurs.

The above-mentioned eutrophication is caused by nitrogen (N) and phosphorus (P), which can be nutrients for the reproduction of algae, such as humus from forest areas, fertilizers used in agricultural fields, manure from livestock products, synthetic detergents, as well as various sewage and factory wastewater. This is a phenomenon that occurs when substances accumulate in a lake and algae activity becomes active.

In this way, in a lake with active algae, eutrophication progresses at a faster rate than the natural state, and when nutrients in various forms continue to flow into the lake and exceed the lake's self-purifying capacity, water pollution gradually occurs, and this process causes water pollution in the lake. This is further promoted by repetition of stratification and inversion phenomena.

The eutrophic lake through the above process causes serious problems such as discoloration of the lake water, bad odor, decreased transparency and increased turbidity due to abnormal growth of algae, anaerobicization of the bottom of the lake, decreased dissolved oxygen, and death of fish and waste. As a result, the aquatic ecosystem is rapidly destroyed and cannot be revived through self-purification.

As a purification technology for these lakes, a closed lake and artificial waterway is created that suppresses green algae and reduces odor by removing suspended substances and reducing the load of pollutants through physical filtration and removing organic matter, nitrogen, and phosphorus through biological treatment. This possible circulation type lake water purification system (registered patent 10-0697985) has been studied.

Meanwhile, nanobubble and microbubble technologies are being studied and applied to water treatment technology to decompose organic matter. As such prior technology, Registered Patent No. 10-1443835 relates to an automatically controlled ozone nano-microbubble generator and a sewage advanced treatment device using a batch-type flotation tank, and ozone nano-microbubbles are generated at the rear of the batch-type activated sludge advanced treatment method. A level at which the water can be reused by installing an automatically controlled batch-type flotation tank and introducing primary treated water (BOD, SS 5~10PPM or less) through secondary treatment through oxidation, flotation, and sterilization mechanisms in the batch-type flotation tank. Technology for processing is being disclosed. Figure 1 is a block diagram showing the internal configuration of the ozone nano-microbubble device of the prior art. The ozone nano-microbubble generator 60 includes a pressure pump 63, a nano-microbubble generator 64, and an air compressor ( 65), and an ozone generator (66). The pressurizing pump 63 is connected to the suction nozzle 61 and sucks the treated water from the batch type flotation tank 50 and supplies it to the nano-micro bubble generator 64. The air compressor 65 and the ozone generator 66 generate compressed air and ozone, respectively, and provide them to the nano-micro bubble generator 64.

However, the above prior art applied ozone nano-microbubbles for the purpose of removing organic matter from rivers, but in lakes and reservoirs where eutrophication and green algae have seriously progressed, there is a limit to the organic matter removal rate due to organic matter deposited at the lower part of the water. There are difficulties in processing it to a level where it can be reused.

Meanwhile, the present inventors used natural raw materials obtained from natural plants to obtain a highly active microbial fermentation starter solution, and used the microbial fermentation starter solution to obtain a microbial fermentation solution for green algae control and sprayed it on green algae occurrence areas to destroy green algae components and odor. A technology related to green algae and odor removal methods has been developed (see Patent No. 10-1915002).

However, when microbial fermentation broth is sprayed into a green algae treatment area or an odor-producing treatment area, the odor removal rate may be reduced due to differences in the activity, growth rate, and change rate of the bacterial mass of the plurality of strains contained in the microbial fermentation liquid. There is a need to improve the reduced appeal odor removal rate.

Republic of Korea Patent No. 10-1443835 (announcement date 2014. 09. 26) Republic of Korea Patent No. 10-1915002 (announcement date 2018. 11. 06)

Therefore, the purpose of the present invention is to effectively remove green algae and bad odors generated in the lake by spraying a highly active microbial fermentation solution for controlling green algae and then injecting a mixture of nano and micro bubbles and microorganisms into the lower part of the treated water area. The purpose is to provide a water purification method.

In addition, another object of the present invention is the water quality of the appeal that can improve the appeal odor removal rate at a time when the appeal odor removal rate is reduced due to differences in the activity, cell growth rate, and cell mass change rate of each of the plurality of strains contained in the microbial fermentation broth. It provides a purification method.

In order to achieve the above-mentioned object, the present invention includes the step (S10) of spraying microbial fermentation liquid on the upper part of the green algae treatment area or the malodor treatment area using a spray means; A step of preparing a mixed solution by mixing microbubbles generated by a nano and microbubble generator that selectively generates nanobubbles and microbubbles with the microbial fermentation broth supplied from the microbial inlet in a mixer (S20); Injecting the mixed solution into the lower part of the treated water area (S30); After the step S30, a step (S40) of measuring the odor removal rate and the change rate of the bacterial mass per unit volume of the strain contained in the microbial fermentation broth for each specific time period; A step (S50) of selecting a strain whose bacterial mass per unit volume of the strain decreases as a strain to be added during the time period when the measured odor removal rate decreases; And when the number of strains to be additionally introduced is plural, the ratio of the bacterial mass change rate to the appeal odor removal rate is calculated for each strain, and the plurality of strains to be additionally introduced are mixed and introduced according to the calculated ratio (S60) ); Provides a method for purifying the water quality of the lake including;

In addition, in the method of purifying the water quality of the lake according to an embodiment of the present invention, before step S30, it further includes the step of injecting nanobubbles into the lower part of the treated water area for a certain period of time.

In addition, in the method of purifying the water quality of the lake according to an embodiment of the present invention, the microbial fermentation broth is obtained by adding molasses and water to a mixed raw material of Houttuynia cordata leaves, lotus leaves, Houttuynia cordata, Houttuynia cordata, and tabasheer and performing a fermentation ripening process. Obtaining a microbial fermentation starter solution through; It is characterized in that it is manufactured by filtering the microbial fermentation starter solution to obtain a microbial stock solution, adding purified water and sea salt to the microbial solution, and fermenting and maturing.

In addition, in the method of purifying the water quality of the appeal according to an embodiment of the present invention, in step S60, the calculated ratio is determined to be greater than the standard value set for the appeal odor removal rate in the time zone when the measured appeal odor removal rate is reduced. If so, a reduction value is added to the mixing ratio, and if it is determined that the appeal odor removal rate is less than the standard value, it is recalculated by adding a weight, and the weight and reduction value are calculated by adding or subtracting the difference between the measured appeal odor removal rate and the set standard value. It is characterized by

According to the water purification method of the lake of the present invention, after spraying treatment with highly active microbial fermentation solution for controlling green algae, a mixture of nano and micro bubbles and microorganisms is injected into the lower part of the treated water area to effectively remove green algae and odor generated in the lake. It can be removed.

In addition, due to differences in the activity, cell growth rate, and cell volume change rate of each of the plurality of strains contained in the microbial fermentation broth, the ratio of the cell volume change rate to the appeal malodor removal rate is calculated at a time when the appeal odor removal rate is reduced, and the ascites to be additionally added is calculated. The odor removal rate can be improved by mixing and adding the strains according to the calculated ratio.

Figure 1 is a block diagram showing the internal structure of a conventional ozone nano-microbubble device.
Figure 2 is a flow chart of a method for purifying water in a lake according to an embodiment of the present invention.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail in the detailed description. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 is a flow chart of a method for purifying water in a lake according to an embodiment of the present invention.

Referring to Figure 1, the water purification method of the lake according to the present invention includes the step of spraying the microbial fermentation broth by a spray means (S10), and the step of mixing microbubbles with the microbial fermentation broth supplied from the microbial injection unit to prepare a mixed solution (S10). S20), a step in which the mixed solution is introduced (S30), a step in which the odor removal rate and the bacterial mass change rate are measured (S40), a step in which strains to be additionally selected are selected (S50), and a plurality of strains to be additionally introduced according to the calculated ratio. It includes a step (S60) in which is mixed and added.

In the step (S10) in which the microbial fermentation liquid is sprayed by a spray means, the green algae components and It is sprayed so that the odorous components are decomposed.

The microbial fermentation broth was manufactured using a method previously developed and registered by the present inventor (see Patent No. 10-1915002), and was prepared by mixing Houttuynia cordata leaves, lotus leaves, Houttuynia cordata, Houttuynia cordata, and tabasheer with molasses and water. Adding and obtaining a microbial fermentation starter liquid through a fermentation maturation process; It is prepared through the steps of filtering the microbial fermentation starter solution to obtain a microbial fermentation solution, adding purified water and sea salt to the microbial solution, and fermenting and maturing to obtain a microbial fermentation solution.

More specifically, the microbial fermentation broth is prepared by placing 20.0 kg of a mixture of 10.0 kg of Japanese fir leaves, 6.0 kg of lotus leaves, 2.0 kg of Houttuynia cordata, 1.0 kg of goldenrod, and 1.0 kg of tabasheer in a fermentation reaction vessel, and 10.0 kg of molasses and 10.0 kg of purified water. If you add and perform the fermentation and maturation process for 12 months in a fermentation room maintained at 30-35℃, you can obtain a thick microbial fermentation starter liquid with white mold dots on the top.

Filter the microbial fermentation starter solution to obtain a microbial fermentation solution, add 1 ton (1,000 kg) of purified water and 25 g of sea salt to 25 kg of the microbial fermentation solution, and ferment and mature for 15 days in a fermentation room maintained at 25-30°C. ^{As a} result of analyzing the microbial fermentation broth using a standard analysis method, ^the representative bacterial species were Lactobacillus paracasei subsp.tolerans at 5.0 A fermented liquid containing microorganisms can be obtained.

The microorganism spraying means 20 is installed in the central part of the treated water area, and the spraying means can be installed at regular intervals 1M below the water surface. At this time, the stagnant contaminated water at the bottom of the treatment water area is pumped and circulated, and is automatically sprayed at a certain time.

Next, the step (S20) in which microbubbles are mixed with the microbial fermentation broth supplied from the microbial injection unit to produce a mixed solution (S20) is a step (S20) in which microbubbles generated by a nano and microbubble generator that selectively generates nanobubbles and microbubbles are injected with microorganisms. This is the stage where the mixed liquid is produced by mixing it with the microbial fermentation liquid supplied from the department in a mixer.

When the microbial fermentation broth in step S10 is sprayed onto the green algae-producing area, most of the green algae components at the top of the green algae-producing area are decomposed and the bad odor can be removed. However, as the green algae outbreak worsens, when organic matter is deposited in the lower part of the green algae area, there is a limit to the decomposition of the organic matter deposited in the lower part of the green algae area just by spraying the microbial fermentation liquid. Therefore, in order to solve this problem, a mixture of microbubbles generated by nano and microbubble generators and microbial fermentation liquid supplied from the microbial injection unit is injected into the lower part of the treated water area to remove organic matter deposited in the lower part of the green algae occurrence area. Can be decomposed effectively.

The nano and micro bubble generator consists of a pressure pump, nano-micro bubble generator, air compressor and ozone nano bubble generator. In the process where the treated water sucked in through the pressurized pump is supplied to the nano-micro bubble generator, air is injected into the treated water through an air compressor. The nano-micro bubble generator generates air-infused treated water into micro-sized bubbles, and the size of the generated micro bubbles is approximately in the range of 10㎛ to 50㎛.

Microbubbles generated by a nano and microbubble generator that selectively generates nanobubbles and microbubbles are mixed with the microbial fermentation broth supplied from the microbial injection unit in a mixer to produce a mixed solution.

The mixer is provided with a stirring unit for stirring the water in which microbubbles are formed and the microbial fermentation broth.

Microbubbles mixed with microbial fermentation liquid attach to microorganisms to form a microcell structure. When sprayed uniformly from the bottom of the lake through a spray nozzle, they float to the surface of the water and are decomposed by microorganisms as suspended residue in the water attaches. In other words, the microbubbles slowly rise, increasing the amount of dissolved oxygen in water where green algae has occurred or may have occurred, and the microorganisms mixed with the microbubbles decompose organic matter and suppress the occurrence of green algae, forming a microbial floc and then being removed.

The step (S30) of injecting the mixed solution is a step in which the mixed solution is introduced into the lower part of the treated water area.

A mixed liquid supply unit may be provided so that the mixed liquid can be injected into the lower part of the treated water area, that is, the bottom side of the appeal. The mixed liquid supply unit includes a supply pipe connected to the mixer, a discharge pipe connected by flexible connecting members for discharging the mixed liquid into the appeal, and a discharge pump for discharging the mixed liquid. At this time, the discharge pressure may preferably be 12 to 15 kg/cm ₂ , but is not limited thereto and may be adjusted depending on circumstances such as obstacles at the bottom of the appeal.

As an embodiment of the present invention, the step of injecting ozone nanobubbles into the lower part of the treated water area for a certain period of time may be performed before the step (S30) of injecting the mixed solution into the lower part of the treated water area.

In the case of generating ozone nanobubbles, the ozone nanobubble generator operates while the treated water sucked through the pressurized pump is supplied to the nano-micro bubble generator, and ozone is injected. The nano-micro bubble generator generates nano-sized bubbles from treated water containing ozone and sprays them into the lake through a spray nozzle. At this time, the size of the nanobubbles generated is approximately in the range of 0.1㎛ to 1㎛.

The ozone nano-microbubble generator operates to generate ozone nanobubbles, and is sprayed uniformly and continuously for a certain period of time at the bottom of the lake through a spray nozzle, thereby oxidizing and sterilizing pollutants. When ozone nanobubbles are sprayed, they rise to the surface of the water, become smaller, and later disappear. At this time, pollutants are decomposed by the strong oxidizing power generated by free radicals. When ozone nanobubbles are sprayed into water, the bubbles float and gradually become smaller. Since the pressure inside the bubble increases in inverse proportion to the bubble diameter, the shrinkage of the bubble leads to an increase in pressure, and if the speed is fast enough, the bubble inside the bubble acts as an adiabatic compressor. The temperature also rises rapidly. As a result, when the bubbles disappear, a region of high temperature and pressure is formed and free radicals are generated. Since the free radicals generated at this time have high generation energy, high oxidizing power is generated in the process of changing to the original stable form, decomposing pollutants existing around.

After the ozone nanobubble contact reaction occurs for a certain period of time, the ozone nanobubble generator stops generating ozone nanobubbles and the mixed solution prepared after generating microbubbles is injected into the lower part of the treated water area. At this time, the contact reaction of the ozone nanobubbles may take about 2 to 3 hours, for example, but the time is not limited to this, and an appropriate time can be operated in consideration of the water quality characteristics of the lake.

The step (S40) in which the appeal odor removal rate and the bacterial mass change rate are measured is a step in which the appeal odor removal rate for a specific time period and the bacterial mass change rate per unit volume of the strain contained in the microbial fermentation broth are measured after the step S30.

In the conventional case, when microbial fermentation liquid is sprayed into a green algae treatment area or an odor treatment area so that the green algae components and odor components are decomposed by spraying means, the activity, growth rate, and change rate of the cell mass of each of the plurality of strains contained in the microbial fermentation liquid are reduced. There is a problem that the odor removal rate decreases at some point due to the difference in .

The present invention is intended to solve this problem, and the problem that the appeal odor removal rate is reduced at a specific time can be solved by measuring the appeal odor removal rate over time and the change rate of the bacterial mass per unit volume of the strain contained in the microbial fermentation broth.

In other words, due to differences in the activity, growth rate, and rate of change of cell mass of each of the plurality of strains contained in the microbial fermentation broth, the strain with a large rate of change in cell volume has a large influence on the reduction of the foul odor removal rate at the time when the odor removal rate is reduced. By determining and calculating the ratio of the change rate of bacterial mass to the odor removal rate in the appeal, and mixing and injecting a plurality of strains according to the calculated ratio, the odor removal rate in the appeal can be improved.

The time zone is defined as a certain time interval, and may be, for example, an interval of 1 hour or an interval of 1 day, but is not limited thereto and may be set according to the water quality characteristics of the lake.

The step of selecting the strain to be additionally introduced (S50) is a step in which the strain whose bacterial mass per unit volume of the strain decreases during the time period when the measured appeal odor removal rate decreases is selected as the strain to be additionally introduced.

As described above, it was determined that the strain with a large change rate of bacterial mass had a large effect on the reduction of the appeal odor removal rate, and the strain whose bacterial mass per unit volume decreased during the time period when the measured appeal odor removal rate decreased was selected as the strain to be added. If there are multiple strains to be additionally introduced, the strains to be additionally introduced can be prioritized and selected in order of the strain with the highest bacterial mass reduction within the setting range of the total reduced bacterial mass.

As an embodiment of the present invention, strains to be additionally introduced can be selected by applying the sum of evaluation scores given for BOD removal rate, COD removal rate, and odor removal rate characteristics in addition to the change rate of bacterial mass.

For example, evaluation scores are given for the rate of change in bacterial mass, BOD removal rate, COD removal rate, and odor removal rate characteristics, and strains to be added can be selected in priority based on the sum of the evaluation scores for each strain.

In the step (S60) in which a plurality of strains are mixed and introduced according to the calculated ratio, when there are a plurality of strains to be additionally introduced, the ratio of the bacterial mass change rate to the appeal odor removal rate is calculated for each strain and the additionally introduced This is the step where a plurality of strains are mixed and introduced according to the calculated ratio.

For example, in a time zone when the appeal odor removal rate decreases, strains whose bacterial mass decreases while the appeal odor removal rate decreases by 1% in that time zone are selected, and among them, the strains with the largest bacterial mass change rate are the first strain and the second strain. In the case where , the rate of change in bacterial mass of the first strain decreased by 2% and the rate of change in bacterial mass of the second strain decreased by 3%, it was judged that the second strain had a large influence on the reduction of the appeal odor removal rate, and the rate of change in bacterial mass to the appeal odor removal rate was determined. The ratio is calculated as 2 for the first strain and 3 for the second strain. Therefore, by mixing the first strain and the second strain according to the calculated weight ratio of 2:3, it is possible to improve the odor removal rate at a specific time when it is reduced. At this time, the amount of input by mixing the first strain and the second strain can be calculated by reflecting the reduction rate of the odor removal rate based on 100 parts by weight of the microbial fermentation liquid input. For example, if the reduction rate of the appeal odor removal rate is 40%, the first strain and the second strain are mixed at a weight ratio of 2:3 and the input amount is 16 parts by weight for the first strain and 24 parts by weight for the second strain. A total of 40 parts by weight.

On the other hand, as an embodiment of the present invention, if it is determined that the appeal odor removal rate at the time when the measured appeal odor removal rate is reduced is greater than the set standard value, a reduction is added to the input amount of the additional strain, and it is determined that it is less than the standard value. If so, weights are added to calculate the input amount of the additional strain.

For example, if the appeal odor removal rate at the point when the measured appeal odor removal rate decreases is 60% of the highest odor removal rate and the set standard is 70%, the appeal odor removal rate of 60% is higher than the set standard value of 70%. Since it is small, in order to quickly increase the odor removal rate, the amount of the additionally introduced strain is calculated by adding a weight to 40 parts by weight of the additionally added strain. Conversely, if it is determined that the appeal odor removal rate at the time when the measured appeal odor removal rate decreases is greater than the standard value, the reduction value is added to calculate the input amount of the additional strain.

Here, the weight and reduction value can be calculated by adding or subtracting the difference between the measured appeal odor removal rate and the set standard value. For example, if the appeal odor removal rate is 60% of the highest odor removal rate and the set standard is 70%, the current appeal odor removal rate of 60% is less than 70% of the set standard, so the input amount of the additional strain is the difference. By applying 10% as a weight, the amount of additional strain added becomes 44 parts by weight, an increase of 4 parts by weight. In this way, by applying weight to the amount of additional input strains, the set standard can be effectively reached and the reduced odor removal rate can be recovered in a short time.

In this way, according to the present invention, the appeal odor removal rate can be improved by quickly and easily selecting strains to be additionally introduced during the time when the appeal odor removal rate is reduced.

In addition, the ratio of the rate of change in cell mass to the odor removal rate in appeal was calculated at a time when the appeal odor removal rate was reduced due to differences in the activity, cell growth rate, and cell mass change rate of each of the plurality of strains contained in the microbial fermentation broth, and the calculated ratio was calculated. Accordingly, the odor removal rate can be effectively improved by mixing and adding a plurality of additional strains.

Meanwhile, the above detailed description should not be construed as restrictive in all respects and should be considered illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (3)

Spraying microbial fermentation liquid onto the green algae treatment area or the upper part of the odor treatment area using a spray means (S10);
A step of preparing a mixed solution by mixing microbubbles generated by a nano and microbubble generator that selectively generates nanobubbles and microbubbles with the microbial fermentation broth supplied from the microbial inlet in a mixer (S20);
Injecting the mixed solution into the lower part of the treated water area (S30);
After the step S30, a step (S40) of measuring the odor removal rate and the change rate of the bacterial mass per unit volume of the strain contained in the microbial fermentation broth for each specific time period;
A step (S50) of selecting a strain whose bacterial mass per unit volume of the strain decreases as a strain to be added during the time period when the measured odor removal rate decreases; and
When the number of strains to be additionally introduced is plural, the ratio of the bacterial mass change rate to the appeal odor removal rate is calculated for each strain, and the plurality of strains to be additionally introduced are mixed and introduced according to the calculated ratio (S60) ;
A water purification method of a lake comprising:
According to paragraph 1,
Before step S30, it further includes the step of injecting nanobubbles into the lower part of the treated water area for a certain period of time,
The microbial fermentation broth includes the steps of adding molasses and water to a mixed raw material of Houttuynia cordata leaves, lotus leaves, Houttuynia cordata, Golden Vinegar, and tabasheer and obtaining a microbial fermentation starter liquid through a fermentation ripening process; A method for purifying the water quality of a lake, characterized in that it is prepared by filtering the microbial fermentation starter solution to obtain a microbial stock solution, adding purified water and sea salt to the microbial solution, and fermenting and maturing.
According to paragraph 1,
In step S60,
The calculated ratio adds a reduction to the mixing ratio if it is determined that the appeal odor removal rate in the time period in which the measured appeal odor removal rate is reduced is greater than the set standard value, and adds a weight if it is determined that the appeal odor removal rate is less than the standard value. and is recalculated,
The weight and reduction values are calculated by adding or subtracting the difference between the measured appeal odor removal rate and the set standard value.