WO2007114528A1

WO2007114528A1 - Apparatus and method for algal bloom control

Info

Publication number: WO2007114528A1
Application number: PCT/KR2006/001181
Authority: WO
Inventors: Hee-Mock Oh; Min-Soo Kim; Hee-Sik Kim; Chi-Yong Ahn; Jae-Won Lee; Seung-Hyun Joung; Kwang-Yong Youn
Original assignee: Korea Research Institute Of Bioscience And Biotechnology; Ilsan Construction
Priority date: 2006-03-31
Filing date: 2006-03-31
Publication date: 2007-10-11

Abstract

The present invention relates to an apparatus and method for algal bloom control using combinational treatment, in detail said apparatus is comprised of an ultrasonicator, water pumps, a porous material treatment tank and a biomaterial treatment tank.

Description

Description APPARATUS AND METHOD FOR ALGAL BLOOM CONTROL

Technical Field

[1] The present invention is an apparatus for algal bloom control that uses a combination of treatments including ultrasonication, biological and chemical materials. In detail, the apparatus contains an ultrasonicator for ultrasonic treatment, water pumps inducing circulation of water, a porous material treatment tank containing algal bloom inhibiting chemical materials, and a biomaterial treatment tank that adds biological material to water. As a result, it is possible to treat a large amount of water in a brief period of time by circulating the water in a body of water and applying a combination of ultrasonication, porous material treatment and/or biological treatment, depending on the state of water pollution. The present invention uses an economical ultrasonication method for inhibiting blue green algae selectively without creating secondary pollution. Moreover, the present invention can be used to break up a stagnating body of water that is creating the conditions for an algal bloom. Therefore, by using the present invention properly, algal blooms in lakes, ponds, reservoirs or intake towers could be controlled effectively.

[2]

Background Art

[3] Emission of polluted water, sewage wastewater and industrial wastewater has bee increasing sharply for 20 years because of industrial development, higher living standards and geometric population growth. Many nutrients such as nitrogen and phosphorus contained in polluted water or wastewater are not perfectly removed in wastewater treatment plants and flow into rivers, lakes or the sea. As a result, eu- trophication has progressed rapidly in most freshwater lakes and seasides near metropolitan areas. Because investment in and development of wastewater treatment equipment have not been sufficient, a large majority of bodies of water in the country exhibit a eutrophic state, and various other environmental problems occur as a result. In particular, the quality of water in Daechung Lake, Paldang Lake, Chungju Lake and others that are sources of fresh drinking water is very important from the perspective of national health.

[4]

[5] "Eutrophication" designates a process whereby a body of water becomes over- enriched with nutrients, nitrogen and phosphorus, which results in the overgrowth of algae, leading to green tide (which corresponds to red tide in the sea). Generally, in river or lake water, if the ratio of nitrogen: phosphorus becomes 15:1 - 5:1, green algae tends to occur. Phosphorus in lakes is precipitated in a sedimentary layer because of the high specific gravity, and the nitrogen to phosphorus ratio of the outer layer of water is 200:1-400:1. As turnover occurs due to changes in water temperature, the ratio becomes 15:1-5:1, and as a result the algae increases sharply. Green algae are commonly called algal bloom or water bloom, and scum forms on the water. But, the most serious problem of eutrophication is deteriorating quality of water because of toxins produced by over-unified and over-concentrated cyanobacteria, especially Microcystis sp., Anabaena sp. and Oscillatoria sp.

[6]

[7] A large amount of scum caused by water bloom of cyanobacteria damages a beautiful sight. Moreover, the scum blocks filtering sand in the water treatment process, and over-chlorination for water sterilization would cause carcinogens to form. In addition, the aqueous ecosystem becomes simplified by dominant cyanobacteria, and dangerous health problems are caused by taste-and-odor compounds such as geosmin and 2-methylisoborneol, hepatic toxins such as microcystin and nodularin, and neurotoxins such as anatoxin, produced by cyanobacteria. Among the toxic compounds, microcystin is most frequently and plentifully detected. In foreign countries, and some cases of damage by that compound in humans and livestock have been reported.

[8]

[9] Accordingly, various technologies have been developed for inhibiting or removing eutrophication and algal bloom quickly and effectively. Hypolimnetic aeration, artificial circulation, sediment removal, algicide addition and phosphorus inactivation are typical representative technologies. Hypolimnetic aeration is the most general method, in which the air delivered to deep water inhibits anaerobic storage and as a result inhibits elution of phosphorus from the soil. Artificial circulation destroys stratification in which cyanobacteria propagate vigorously. However, hypolimnetic aeration and artificial circulation are not economical. In this country, these two methods are commonly used, but are not very effective.

[10]

[11] Sediment removal removes sediment that contains highly concentrated phosphorus, which reduces internal loading of phosphorus and maintains low concentrations of nutrients. However, the results of this method are not visible in a short time and it is not economical. Algicide addition or phosphorus inactivation (a phosphorus precipitation method by Fe, Al or Cu salts) has excellent short-term effects. However, these methods produce secondary pollution, and the Ion-term efficiency is not good. Other methods generally used in this country include shielding curtains, loess scattering, etc. The shielding curtain inhibits algal increase by cutting off sunlight needed in photosynthesis. However, the application is very restricted, and the setup cost is high. [12] [13] Clay scattering is used in red tides, but has no comparable effect in freshwater lakes. Previously, ships were used to remove algae. The operating cost, however, is too high, so this method is no longer used. [14] [15] Published Korean patent documents include algal removal methods using: algicide containing phyitic acid extracted from cereals [registered patent publication No.180468

]; ceramic material [publication of unexamined patent application No.2000-19515]; porous ceramic powder for red tide removal [registered patent publication No.337393]; electrolysis [publication of unexamined patent application No.1998-82153]; an apparatus using coagulation and filtration [registered patent publication No. 317537]; electric floatation [publication of unexamined patent application No. 2001-48041]; lipopolysaccharide red tide inhibition method [registered patent publication No.384284

]; plant extract [patent application No.2002-34173]; and multicationic polymers

[registered patent publication No.278220]. However, most of these methods are not used in practice. [16]

Disclosure of Invention

Technical Problem

[17] To solve these problems, the present inventors found that ultrasonic waves are effective against algal breeding, especially cyanobacteria, and developed a number of algal removing materials. The present inventors then patented the finding that ultra- sonication has an excellent inhibiting effect on algae, especially cyanobacteria [registered patent publication No.0443266], found that the ultrasonication treatment is more effective during a certain time period of the day and patented an effective algal controller [registered patent publication No.0504452], and patented an improved algal growth inhibiting apparatus [registered patent publication No.0528599].

[18] In addition, the present inventors developed and patented a cyanobacteria growth inhibiting composition containing allelochemicals extracted from ground plants [registered patent publication No.0454096], and patented chemical and biological materials for cyanobateria growth inhibition [patent application No.2003-72682, 2003-0013402].

[19] However, the patented technologies were not effective in inhibiting algal growth in the field. Since ultrasonication covers a narrow area, several ultrasonic transducers are needed to treat a wide body of water. In addition, ultrasonication alone is not sufficient to control cyanobacteria effectively. Moreover, a copious amount of the chemical or biological materials is needed for a single use. It is expensive to produce and treat a large amount of the material. In addition, it would bring about secondary environmental pollution.

[20] Therefore, the inventors developed a combined apparatus consisting of an ultra- sonicator, a biomaterial, and a chemical material, and the three elements can be used in various combinations depending on the water quality. The inventors applied the apparatus on a large scale in the field for five months and demonstrated it to be effective.

[21]

Technical Solution

[22] To solve the problems of prior methods, the inventors produced a combination of algal controlling biomaterial- and porous material-charged tanks, water pumps inducing circulation of water, at least one ultrasonicator, and transducers. The inventors demonstrated that the combined apparatus was effective in algal bloom control in a 12,000-ton scale pond.

[23]

[24] In detail, the combined apparatus for algal bloom control contains one or more water pumps (10) operating in the region of water in which the algae has propagated heavily and discharging in a particular direction through an outlet (3); ultrasonicator and transducers (6) radiating ultrasonic waves into the water sucked in by the water pump; biomaterial treatment tank (4); porous material treatment tank (5) charged with porous silicate material; one or more supplementary transducers (6); a frame (7) to fix the water pump (10), the transducer, the biomaterial treatment tank and porous material treatment tank in the water; control means (12) to control the operation of the water pump, the ultrasonicator, the biomaterial treatment tank, the porous material treatment tank; and a power supply (11).

[25]

[26] The objectives of the present invention are to: treat a large amount of water quickly through the combination of the ultrasonicator and water pump; maximize the algal growth inhibition effect with the minimum number of ultrasonicators; provide an apparatus and a method that inhibits secondary pollution, using ultrasonication to control cyanobacteria selectively; and break up the stagnant body of water suitable for cyanobacterial growth.

[27]

Advantageous Effects

[28] As previously demonstrated, the combined apparatus of the present invention represents effects as follow. [29] [30] 1) The apparatus can treat a large-scale body of water quickly, because the water pump circulates the sonicated water to the whole surface of a pond. [31] [32] 2) Supplementary transducers installed far from the ultrasonicator maximize the algal bloom controlling effect. [33] [34] 3) Co-treatment by the ultrasonicator and water pump breaks up a stagnant body of water, which provides good conditions for cyanobacterial growth. [35] [36] 4) Ultrasonication, which has a low operating cost, has an inhibition effect specific to cyanobacteria, and the method would not cause secondary environmental pollution. [37] [38] 5) In case of rapid cyanobacterial growth, use of only a small amount of biomaterial in the combined apparatus has a synergistic effect. [39]

Brief Description of the Drawings

[40] Fig. 1 shows the whole schematic diagram of the apparatus of the present invention.

[41] Fig. 2 is a diagram that shows water flow in the biomaterial treatment tank and porous material treatment tank. [42] Fig. 3 shows the ultrasonic intensity in the body of water when ultrasonic waves are generated.

[43] Fig. 4 shows the growth inhibition rate of Microcystis sp. according to various concentrations of rice straw extract as a biomaterial. [44] Fig. 5 shows the growth inhibition rate of Microcystis sp. according to various processing methods of rice straw extract as a biomaterial. [45] Fig. 6 shows irradiance (A) and rainfall (B) in the field while the apparatus of the present invention is operated. [46] Fig. 7 shows total nitrogen (TN, Fig. 7-A) and total dissolved nitrogen (TDN, Fig.

7-B) in the field during operation of the apparatus of the present invention. [47] Fig. 8 shows total phosphorus (TP, Fig. 8-A) and total dissolved phosphorus (TDP,

Fig. 8-B) in the field during operation of the apparatus of the present invention. [48] Fig. 9 shows the algal controlling effect in the field during operation of the apparatus of the present invention. [49] [50] <Description of sign about major parts of drawings> [51] 1: biomaterial supplying means 2: breathing hole

[52] 3: outlet 4: biomaterial treatment tank

[53] 5: porous material treatment tank 6: ultrasonicator

[54] 7: frame 8: biomaterial output valve

[55] 9: direction controlling valve of water

[56] 10: water pump

[57] 11: power supply 12: control means

[58]

Best Mode for Carrying Out the Invention

[59] The best mode for execution of the present invention is demonstrated as follows with reference to the drawings.

[60]

[61] In the combined apparatus of the present invention, the water to be treated is sucked into the frame, and after treatment, discharged in a particular direction using the water pump (10) placed in the two side ends of the frame (7). In the next water pump there are two biomaterial treatment tanks, and the biomaterial from the biomaterial supplying means (1) is mixed into the water sucked into the frame by the water pump. Then the water is moved to the porous material treatment tank. The biomaterial treatment tank can store the biomaterial and discharge it out of the frame through the biomaterial discharge valve toward the body of water. The inner space of the porous material treatment tank is separated by many partitions, and the separated rooms are connected with passages through the upper and lower ends in turn. As shown in Fig. 2, as the water flows upward and downward in turn, the water makes sufficient contact with the silicate porous material so that the phosphorus and heavy metals in the water are adsorbed and removed. At least one transducer (6), connected with the ultrasonicator, is installed at the lower end of the biomaterial treatment tank and/or porous material treatment tank to radiate ultrasonic waves into the water sucked into the frame by the water pump (10). The ultrasonicator (not shown in the drawings) may be placed near the power supply or with the control means, or with a transducer.

[62]

[63] Besides the transducers installed inside of the frame (7), at least one supplementary transducer is installed in the water far from the frame. The supplementary transducers (6') out of the frame are multi-angular pillar or circular pillar type transducers, which can radiate ultrasonic waves in many directions for effective ultrasonic treatment, while the transducers in the frame are flat types.

[64]

[65] The control means (12) outputs controlling signals to automatically control on/off, number of times of operation, and operating time of the water pump and ultrasonicator. The control means controls the input of biomaterial into the biomaterial treatment tank, according to time and the concentration of phosphorus. In addition, the control means controls the combination of the ultrasonication process, biomaterial treatment process and porous material treatment process, or the processing sequence according to the degree of pollution, season, temperature of the water, etc.

[66]

Mode for the Invention

[67] The inventors demonstrated that ultrasonication could inhibit the growth of algae, especially cyanobacteria [Korean patent application No.2002-34172]. The inventors also patented cyanobacteria growth inhibiting material containing allelochemicals extracted from a ground plant [Korean patent publication 10-0454096], and developed chemical and biological materials for controlling cyanobacteria [Korean patent application No.2003-72682, 2003-13402].

[68] The inventors improved these technologies and developed a combined apparatus.

[69]

[70] The present invention contains at least one water pump, at least one ultrasonicator, at least one porous material treatment tank, at least one biomaterial treatment tank, power supply and control means.

[71]

[72] As shown in Fig. 2, the water pump sucked in water from the region in which algae propagated heavily, and discharged the water upward through the outlet (3). The water pump was installed to the two-sided end of the frame. Two biomaterial treatment tanks (4) at the next water pump stored the biomaterial from biomaterial supplying means (1) or mixed the biomaterial with water sucked in by the water pump to treat the water. The biomaterial could be mixed with water in the biomaterial treatment tank, and/or could be mixed outside of the tank by the biomaterial output valve.

[73]

[74] Biomaterials in the present invention designate allelochemicals. Allelopathy is a reaction in which a certain compound emitted from a plant exercises influence on the growth of another plant. Well-known allelochemicals of food crops, medicinal crops, wild plants, and aquatic plants are extracts of rice straw, wheat straw, barley straw, leguminous plants, alfalfa, Cnidium officinale, ginger, broadleaf trees such as oak trees, and needle-leaf trees. Known allelochemical compounds of plants include, terpenoids, steroids, phenols, coumarin, flavenoids, alkaloids and tannin, which inhibit germination, growth, respiration, photosynthesis, nutrient absorption or hormone synthesis. The present inventors patented rice straw extract, extracted by a polar solvent, as a cyanobacteria growth-inhibiting compound. In the present invention, one or more biomaterials selected from a group consisting of extracts of rice straw, wheat straw, barley straw, broadleaf and needle-leaf could be used to inhibit algal growth. Moreover, in the present invention, cultured media for environmental microorganisms for water treatment such as Bacillus subtillis, etc. could be applied as a biomaterial.

[75]

[76] Next, the water was treated in the porous material treatment tank. The inner space of the porous material treatment tank was separated by many partitions, and the separated rooms were connected by passages through the upper and lower ends in turn. As shown in Fig. 2, as the water flowed upward and downward in turn, it made sufficient contact with the silicate porous material so that the phosphorus and heavy metals in the water were adsorbed and removed.

[77]

[78] The silicate porous material is potassium silicate compound synthesized from plaster, quicklime and steel mill slag. The major ingredients are SiO and CaO, with lesser amounts of Al, Fe, Mg and K. The pH is about 8-9, the specific gravity is 0.35-0.45, and the specific surface area is about 50D/g. The porous silicate has copious numbers of fine pores to adsorb phosphorus contained in water.

[79] At least one transducer (6) connected with the ultrasonicator was installed at the lower end of the biomaterial treatment tank and/or porous material treatment tank to radiate ultrasonic waves into the water sucked into the frame by the water pump (10). The ultrasonicator (not shown in the drawings) could be placed near the power supply or with the control means, or with a transducer.

[80]

[81] In the apparatus of the present invention, besides the transducers installed inside of the frame (7), at least one supplementary transducer may be installed in the water far from the frame. The supplementary transducer (6') out of the frame can be a flat type like the transducer in the frame, or a pillar type transducer that can radiate ultrasonic waves in many directions.

[82]

[83] The control means (12) outputs controlling signals to automatically control on/off, number of times of operation, and operating time of the water pump and ultrasonicator. The control means controls the input of biomaterial into the biomaterial treatment tank according to the time and the concentration of phosphorus. In addition, the control means controls the combination of the ultrasonication process, biomaterial treatment process and porous material treatment process according to the degree of pollution, season, temperature of the water, etc.

[84] [85] The present invention will be explained in more detail with reference to the following Examples and Experimental Examples. However, the present invention can be utilized in various ways not limited to these examples and experimental examples.

[86]

[87] Example 1: Preparation of biomaterial

[88] The biomaterial used in an example of the present invention was extracted from rice straw. In detail, 7kg of rice straw and 501 of water were mixed and naturally extracted for 3 months in a large vessel. The extract of rice straw was filtered with GF/C filtering paper (Whatman) in order to remove solid matter, and then liquid biomaterial was acquired. To measure the dry weight of liquid biomaterial, 1OD of liquid biomaterial was put into a foil dish, and was then dried in a dryer at 8O⁰C. In the drying process the weight was measured at intervals, and when the weight was no longer changing, the dried weight of the extract was measured. The biomaterial prepared was used for algal growth inhibition in the present invention.

[89]

[90] Example 2: Manufacture of an apparatus for algal growth inhibition

[91] The apparatus for algal growth inhibition contains an ultrasonicator as a major element, and the ultrasonicator has a frequency of 22 kHz and maximum power of 630W. In an example, four transducers with thickness of 55mm and diameter of 25cm were used in the apparatus. The apparatus, with a timer, could change the treatment time periods, and the apparatus was produced in order to control power intensity. In the combined treatment apparatus, three treatment tanks were produced for packing or storage of porous material and biomaterial.

[92]

[93] Experimental example 1: Measurement of chlorophyll -a

[94] Growth rate of Microcystis sp. was measured by detecting the amount of chlorophyll-a. Since algal concentration cannot be described as bacterial populations or CFU (Colony Forming Units), it was described using dried bacterial weight or concentration of chlorophyll-a. Chlorophyll-a was extracted as follows. A sample was filtered by GD/X PVDF FILTER(25mm, 0.2D), chloroform methanol=2:l(v/v) solvent was added, and it was then incubated for 24 hours in a cool, dark place. The extract was detected by a fluorometry in conditions of excitation 440nm, emission 665nm. From detected fluorescence value, the concentration of chlorophyll-a was calculated as follows.

[95] Concentration of chlorophyll-a(D/L) = [0.204x(fluorescence value)x 5.01]/[amount of sample(D)]X6

[96]

[97] Experimental example 2: Growth inhibition of Microcystis sp . by biomaterial treatment according to various concentrations of biomaterial

[98] Microcystis sp. was treated with the biomaterial prepared in Example 1 in concentration of 1, 10, 50, and 100ppm(w/v) respectively, and compared to a control. Growth inhibition of Microcystis sp. was detected. Microcystis sp. was cultured at 3O⁰C, with lOOrpm stirring, for 7days under continuous light. The changes of cell concentration were measured using fluorescence.

[99] As shown in Fig. 5, lppm of the biomaterial showed a 20% growth inhibition rate, and 10 ppm of the biomaterial showed a 60% growth inhibition rate compared to the control in which the biomaterial was not treated. However, the inhibition effect of treatment with a concentration of more than 25ppm increased slowly. Therefore, in field application 1-10 ppm of the biomaterial could be effective.

[100]

[101] Experimental example 3: Growth inhibition of Microcystis sp . by biomaterial treatment according to various biomaterial processing methods

[102] The liquid extract of biomaterial was filtered using autoclave or membrane filter

PTFE (Whatman, pore size 0.2D), and thevMicrocystis sp. was treated with lppm and lOppm of the filtered extract. As shown in Fig. 5, autoclaved biomaterial (B) inhibited bacterial growth to a degree similar to the non-treated control (A) at 1 and lOppm. The cyanobacteria inhibition substance in the biomaterial is heat-resistant. In Fig. 4 and Fig. 5, the term "Humic substance" is synonymous with the biomaterial in the present invention. Membrane-filtered biomaterial (C) was less effective than the control. A portion of the cyanobacteria inhibition substance might be removed in the membrane filtering process. From these results, the cyanobacteria inhibition substance in the biomaterial is believed to be a heat-resistant, low molecular weight substance.

[103]

[104] Experimental example 4: Algal growth inhibition effect in large -scale field

[105] 4-1. Choice of experimental field

[106] Ponds A and B, in Cheonan city, Chungnam province, Korea, were chosen as experimental fields. Pond A, the control, was not treated, and pond B was treated using the apparatus of the present invention. The two ponds were close together, and the structures were same. The widest point was approximately 100m, the narrowest was about 50m, average depth was about 2.5m, and the deepest point was 4m. The ponds each have 12,000ton water volume. The ponds have no influx and no water treatment system, and as a result, algal blooms occur every year. The field experiment took place from June 1^st, 2005 to October 7 , 2005, and water samples were collected and analyzed regularly twice a week. During the experiment, the operation sequence was divided into pre-treatment (I), ultrasonication (II), porous material treatment (HI), supplemental transducer treatment (IV) and biomaterial treatment (V), as shown in Fig. 6 - Fig. 9. [107] [108] 4-2. Changes in weather and water quality during experiment

[109] As shown in Fig. 6B, higher than average rainfall (1 - 2 times per week) occurred during the experimental period, providing conditions unsuitable condition for algal growth.

[110] As shown in Fig. 7 and Fig. 8, total nitrogen and total dissolved nitrogen in the treatment pond were higher than those of the control pond (Fig. 7). Total phosphorus and total dissolved phosphorus showed patterns similar to the control pond (Fig. 8). The result demonstrates that physical and chemical properties of the treatment pond were more adequate for algal growth than that of the control pond.

[I l l]

[112] 4-3. Algal bloom control effect using the combined apparatus

[113] During the field experiment, changes in the concentration of chlorophyll-a were detected (Fig. 9). In the control pond, a greater than 2-fold increase in the concentration of chlorophyll-a (compared to the concentration at experimental onset, June 21, 2005) occurred twice in August because of plentiful solar radiation. In comparison, the concentration was stable at no more than 50% of onset in the treatment pond using the combined apparatus in July and August (Fig. 9). Algal control using the combined apparatus was excellent. In addition, a synergistic effect of simultaneous treatment by ultrasonication and the materials was detected (Fig. 9-III). At first, a silicate porous material was used for green algae treatment from September 1, 2005, at a concentration of O.lg/f. As shown in Fig. 9-iπ, in the treatment pond, the concentration of green algae decreased 30% compared with onset, but in the control pond, the concentration increased. The results demonstrate that treatment by ultrasonication and silicate porous material creates a synergistic effect.

[114]

[115] To maximize the algal control effect using more intensive ultrasonication, a supplementary ultrasonicator was installed on September 8, 2005 (Fig. 9-IV). However, as shown in Fig. 6, accurate data were not collected because of heavy rain of 150mm/day on those days. As shown in Fig. 9-IV, in the control pond, the algal concentration during this period increased suddenly because of an increase in influx from outside due to the heavy rain. Finally, the algal control effect of the biomaterial was tested. Co- treatment by ultrasonication and biomaterial created a synergistic effect (Fig. 9- V). The biomaterial treatment followed silicate porous material treatment. The biomaterial treatment onset was September 18, 2005, and the concentration was 0.1 D/l. After treatment with the extract of rice straw, the algal concentration decreased gradually in the treatment pond, in contrast with the concentration in the control pond, which increased. The results demonstrated that the combined apparatus and methods of ultra- sonication, biomaterial treatment and porous material treatment were effective, and can be practically applied in a large-scale field.

[116]

Industrial Applicability

[117] Algal bloom owing to eutrophication is thought to be a serious environmental problem. Various methods for algal growth control have been attempted, but have not been very effective. The best method is to inhibit the influx of nutrients, but that is not practical. The apparatus and methods of the present invention produce excellent algal removal effects in a short time at low cost.

[118] They can control algal bloom, especially cyanobacteria, without secondary pollution, and it can be applied in ponds, lakes, reservoirs or intake towers.

Claims

[1] Apparatus for algal bloom control using a combined treatment system comprised: an ultrasonicator that radiates ultrasonic waves to algae; a water pump that circulates water in lake; porous material treatment tank filled with porous silicate material that removes phosphorus contained in water; a biomaterial treatment tank that supplies biomaterial to water which inhibits algal growth; and a control means. [2] The apparatus of claim 1 wherein said biomaterial is one or more biomaterials selected from a group consisting of extracts of rice straw, wheat straw, barley straw, broad leaves, and needle shaped leaves, and culture fluid for environmental microorganisms. [3] The apparatus of claim 1 wherein said ultrasonicator is comprised of two or more transducers, one or more of which is placed in a frame that contains a porous material treatment tank and a biomaterial treatment tank, and one or more of which is placed in the water, far from the frame, and is cylindrical in shape. [4] The apparatus of claim 3, wherein said transducer placed in water is shaped as a multi- angular pillar, and radiates ultrasonic waves in many directions. [5] The apparatus of claim 3, wherein said transducer placed in water is shaped as a circular pillar, and radiates ultrasonic waves in many directions. [6] The apparatus of claim 3, wherein said transducer placed in a frame is set on the bottom of the porous material treatment tank or biomaterial treatment tank, and radiates ultrasonic waves upward. [7] Method for algal bloom control using a combined treatment system with at least one selected from the group, according to the water pollution level, concentration of phosphorus and algal bloom degree, comprising an ultrasonication process in which an ultrasonicator radiates ultrasonic waves to algae in water; a porous material treatment process that removes phosphorus contained in water with porous silicate material; and a biomaterial treatment process wherein said biomaterial is selected from a group consisting of extracts of rice straw, wheat straw, barley straw, broad leaves, needle shaped leaves, and culture fluid of environmental microorganisms, which inhibits algal growth.