JPS594489A - Treatment of red tide - Google Patents

Abstract

PURPOSE:To separate and recover efficiently red tide planktons and fine particles of a ferromagnetic material, by applying an ultrasonic wave to the concd. matter of the red tide planktons and the fine particles of the ferromagnetic material then passing the water through a magnetic filter and recovering both separately. CONSTITUTION:Raw water contg. red tide planktons is put into a stirring tank, where fine particles of a ferromagnetic material such as magnetite are added thereto under thorough stirring to form the fine particulate materials which are entangled with each other. Such particulate materials are captured with a settling device or the like and are introduced as a granular slurry into a dispersion column under application of an ultrasonic wave, where the fine particles of the ferromagnetic material and the fine particles of the red tide planktons are dispersed separately. The slurry is introduced through an inflow port 25 into a magnetic filter 17, where only the fine particles of the ferromagnetic material are captured with magnetized filter media 32, and the slurry having a high content of the red tide planktons is flowed out through an outflow port 26.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating red tide, and in particular, it aims to provide a method for eliminating red tide, which poses a pollution problem, and at the same time collecting red tide plankton, which is a causative agent of red tide.

Methods for separating and removing red tide plankton from red tide raw water include (A) a method of first taking red tide raw water and treating it with (1) coagulation sedimentation method or (2) pressure flotation method; and (B) a method of directly spraying clay, iron powder, etc. into red tide-like raw water to cause the red tide plankton to settle can be considered.

However, in the coagulation-sedimentation method (1), the sedimentation speed is at most 1 to 2 m/hour and not only does it require a huge area, but also when the treatment process is installed on a ship, for example, the free water surface is large. There is a drawback that the performance becomes unstable due to the influence of turbulence, but in the pressure flotation method (2), the flotation speed is about 10 to 15 m/hour, which is an improvement over the coagulation sedimentation method. If processing equipment is placed on a ship, it will be affected by turbulence, making the production of colloid air unstable and making pressurized flotation itself difficult. The drawback is that a recovery rate cannot be obtained. In addition, the direct injection method (3) into raw water in the form of red tide is far from a fundamental solution because the blank remains in the water body without being removed, and after settling, it rots and recontaminates the water area. Moreover, it is no exaggeration to say that this method is rather anti-social, as re-contamination after decomposition occurs quickly and repeated pollution occurs rapidly.

Therefore, the present inventors conducted intensive research on a method for removing red tide plankton from red tide-like raw water that does not have the above-mentioned drawbacks, and found that (a) the surface of red tide plankton is highly curved and is still covered with a film of mucus. (b) We confirmed the fact that many red tide plankton have the property of being sensitive to geomagnetism, have good compatibility with ferromagnetic particles, and are sensitive to strong magnetic fields. The findings suggest that if ferromagnetic particles are mixed with raw water, the particles will easily adhere to red tide plankton, and if these particles are captured together with ferromagnetic particles in a magnetic field, red tide plankton can be effectively separated. On the same day, red tide-like raw water was taken in a method for separating and collecting red tide plankton, and ferromagnetic fine particles were added to it, thoroughly stirred, and passed through a magnetic filter. We have filed a patent application for a red tide treatment method characterized by passing water through the filter and capturing and separating red tide plankton in a concentrated state along with ferromagnetic fine particles in the filter media section of a magnetic filter.

Although the above application was able to effectively capture and recover red tide plankton from red tide raw water, what was recovered was a slurry in which red tide plankton and ferromagnetic fine particles were dispersed. Dehydrating the ferromagnetic particles as they are, turning them into a cake, and disposing of them, burying them in a landfill, or incinerating them not only makes it impossible to reuse the ferromagnetic particles, which is disadvantageous in terms of resource conservation, but also closes off the possibility of utilizing the recovered red tide plankton. Therefore, the above application proposal method alone was not necessarily satisfactory.

Therefore, the present inventors have investigated the use of red tide plankton and ferromagnetic fine particles obtained by the method proposed in the above-mentioned application.
As a result of further research on the method of separating and recovering each fraction, it was confirmed that when the above-mentioned granules are subjected to ultrasonic treatment, the two can be efficiently separated, and the present invention has been completed.

That is, the present invention takes red tide-like raw water from a body of water, adds ferromagnetic fine particles to form aggregate or floc-like particles in which red tide plankton and ferromagnetic fine particles are entangled, and extracts red tide-like raw water from the water. In a method for collecting red tide plankton in a concentrated state together with ferromagnetic particles, the concentrate is subjected to ultrasonic treatment and then water is passed through a magnetic filter to obtain a slurry with a high content of red tide plankton and ferromagnetic particles. The gist of this article is a method for treating red tide, which is characterized by separating the slurry into a high-density slurry and collecting it separately.

The slurry in which ferromagnetic particles and red tide plankton are mixed is not simply a mixture of individual particles, but is entangled with each other to form flocs or aggregates, and is composed of ferromagnetic particles and red tide blanks. are combined to form a single granule.

The individual particles of this material cannot be easily dispersed, and cannot be separated by conventional centrifugal separation (centrifugal sedimentation) that utilizes the difference in specific gravity.

Therefore, in the method of the present invention, first, ultrasonic waves are irradiated and the granules are separated into red tide plankton particles and ferromagnetic particles into a slurry, which is then passed through a magnetic filter to make only the ferromagnetic particles. The aim is to capture them with the filter and separate them from red tide plankton.

The present invention can also be applied onboard a red tide collection ship, and is generally advantageous in countermeasures against red tide plankton contamination in drinking water treatment, and in countermeasures against red tide plankton contamination when seawater, lake water is used as industrial water or industrial raw material. It can be applied to

Before describing the structure of the present invention in detail, Table 1 first shows the definitions of red tide and red tide plankton as used in the present invention.

Hereinafter, one embodiment of the present invention will be described according to the flow shown in FIG. In Figure 1, 1 is a red tide-like water area, 2 is a raw water intake line, 3 is a garbage removal device and water intake device, 4 is a stirring tank, 5 is an addition equipment for ferromagnetic particles, and 6 is a ferromagnetic particle mixture. line, 7 is inorganic flocculant and/or polymer flocculant injection equipment installed as necessary, 8 is the same flocculant addition line, 9 is a particulate material of red tide plankton and ferromagnetic fine particles dispersed and flowing 10 is a magnetic filter or other magnetic treatment device or precipitation device; 11 is a purified raw water discharge line; 12 is a wash water outflow line of the magnetic filter or other magnetic treatment device or precipitation device 10;

13 is a pit containing a granular material-dispersed slurry of red tide plankton and ferromagnetic fine particles, 14 is the above-mentioned granular material/dispersed slurry suction line, 15 is an ultrasonic irradiation dispersion tank, and 16 is a pit in which red tide plankton and ferromagnetic fine particles are dispersed, respectively. Slurry flowing line, 17 is a magnetic filter, 18 is a line where slurry with a high content of red tide plankton is flowing, 19
20 is a relay bit for the slurry, 20 is a line for taking out the same slurry cake, 23 is a line through which a slurry with a high content of ferromagnetic particles obtained by washing the magnetic filter 17 flows, and 24 is a ferromagnetic particle collection storage tank.

The raw water containing red tide plankton from the red side water area 1 passes through the water intake line 2 and the water intake device 5 and reaches the stirring tank 4 whose main function is stirring. Fe3O4), hematite (Fe
zO3), cobalt oxide, chromium pentoxide, etc.], the ferromagnetic fine particles and red tide plankton become entangled and adhere to each other. At this time, if necessary, an inorganic flocculant (one that becomes Fe(OH)3, At(OH)3, etc. when dissolved in water), a polymeric flocculant (sodium alginate, etc.) is passed from equipment 7 through line 8. can be added to further promote the entanglement.

The strong ik particles and the red tide plankton become entangled and become one fine particle, which reaches the magnetic filter (this configuration will be described later) or other magnetic processing device or sedimentation device 10 via line 9, and this fine particle Objects are captured and treated, and the treated clean water is discharged into the water area 1 via a discharge line 11.

Magnetic filter or other magnetic treatment device or sedimentation device 10
The captured fine particles are washed or scraped off by washing water supplied from a line (not shown), and are then sedimented and separated to reach the slurry bit 13 via line 12. This slurry bit 16 is used to prevent the deposition of particulate matter.

Stirring is preferably performed.

The granular slurry is transferred from the slurry pit 13 to the suction line 1
4 and enters the ultrasonic irradiation dispersion tank 15.

In this ultrasonic irradiation and dispersion tank 15, the ferromagnetic fine particles and the red tide plankton particles, which were particulate matter, are separately dispersed. A slurry in which each particle is separately dispersed flows through line 16 and reaches magnetic filter 17 . The ferromagnetic particles are captured by the magnetic filter 17, and the slurry with a high content of red tide plankton is sent to the relay bit 19 via line 18, and then to the dehydrator 2 via line 20.
1, dehydrated red tide plankton becomes dehydrated cake 2
The waste is collected from line 22 and put to effective use.

On the other hand, since the magnetic filter 17 will soon become full of collected ferromagnetic particles, it is washed as needed with washing water sent from a line (not shown), and a slurry with a high content of ferromagnetic particles is passed through the line. 23 and then sent to a collection storage tank 24. In this way, red tide plankton and ferromagnetic particles are separated and collected.

In 10, if a magnetic filter similar to the magnetic filter 17 is used, ferromagnetic fine particles and red tide plankton are aggregated or flocculated and captured as particulate matter, and then washed as appropriate through the above-mentioned process. These particles are collected via line 12 into bit 13 .

Also, other magnetic processing devices (e.g. rotating disk type)
In this case, the scraped slurry (the aggregated granules are collected into the bit 13 via the line 12). In the case of a medium-fine sedimentation tank (agglomerated or flocculated granules will sink (different from solid red tide plankton, ferromagnetic fine particles are well intertwined, so they will settle very well) Treated water is passed through line 11 as excrement water, and granular slurry that has been aggregated or flocculated as sediment slurry is passed through line 12 - Bit 1.
It will be collected on 3rd.

The main part of the present invention d1 is to separate and collect the entangled granules of red tide blank 1 and ferromagnetic fine particles obtained in step 10 into individual particles. ,
In this case, any type or method of one of the 10 devices does not matter.

Figure 2 is a schematic diagram showing one embodiment of the magnetic filter 17. In Fig. 2, the same parts as in Fig. 1 are shown, and 25 indicates the red tide plankton and ferromagnetic fine particles that have been separated and dispersed separately in the ultrasonic irradiation dispersion tank 15 in the pretreatment process. The slurry passes through line 16 to magnetic filter 17 η1. 26 is the outflow 1 of the slurry filtrate (slurry with a high content of red tide plankton), 27 is the backwash river water inlet for backwashing, and 28 is the slurry after backwashing (strong The outflow port 29 of the slurry (with a high content of magnetic fine particles) is dark blue; it is made of iron to prevent the magnetic flux from the magnet 30 (described later) from being released into the filter media 32 and to work effectively on the filter media 32. Soft iron or pure iron is used. 30 is a magnet (permanent magnet or electromagnet), 3
1 is a pole piece made of perforated plate-like soft iron or pure iron, which allows water to pass through; 32 is a filter media, which is a magnetic constant or ferromagnetic material, and when placed in a magnetic field. Materials that are easily magnetized (for example, SUS 420.4
50, one condyle is 14, 111-Hyotsutaichi, etc.) Also, a wire mesh or lattice filter made of a material containing the substance is 1A) (rotated/next) irradiated with 1° ultrasound The slurry in which red tide plankton and ferromagnetic fine particles are separately dispersed in the dispersion tank 15 is different from the state in which they are thoroughly mixed in the stirring tank 4, and their entanglement is extremely high. Since the slurry is filtered out by the sonic irradiation, the slurry that enters the magnetic filter 17 from the inlet 25 passes through the pole piece 31 and reaches the filter mesh 62, where only the ferromagnetic fine particles are filtered by the magnet 30. The slurry with a high content of red tide plankton is captured by the magnetized filter media 62 due to the magnetic field generated by the magnetic field, and flows out from the outlet 26 and flows through the line 18 in FIG.
I ended up going to the river.

On the other hand, even if the same magnetic filter 17 is used at 10 in FIG. 1, the slurry flowing into the magnetic filter 17 is sufficiently stirred in the stirring tank 4 and is tightly entangled with ferromagnetic particles such as red tide plankton. Since the particles fit together, they are captured as one in the fill-mezzo 132.

In either case, 10 and 17 in Figure 1 require regeneration or sedimentation separation and are operated intermittently, so regardless of the type of 10, two or more series of magnetic filters 17 are installed for continuous operation. Being able to do things is feminine.

Next, specific examples of the present invention will be shown.

Using magnet 5 [] in Figure 2 as an electric magnet, red tide plankton and red tide plankton in real seawater collected from the Seto Inland Sea are added to phosphorus, chitsui, vitamins, etc. and further concentrated in a tank. Magnetite (Fe3O4) was used as the ferromagnetic fine particles supplied from ship j5 in Fig. 1. This product has a purity of 98% or more and a true specific gravity of 51 ri/πf1 bulk specific gravity of approximately 0.5
f/'r ml, average particle size 052μ, magnetization 85.4
einu /'f/ (in 7koe).

Experimental data are shown in Table 2. N11 in Table 2 is a comparative experiment to clarify the effects of the present invention. That is, the first
This is an example in which the ultrasonic treatment is not performed in the dispersion tank 15 shown in the figure.
There are 9 cases in which the residence time of the liquid flowing into the filter and the operating method of the electromagnetic filter are slightly different. As the ultrasonic treatment time increases, the purity of Fe3O4 recovered from line 25 in Figure 1 decreases to 75% compared to the control 54%.
．． The SS contamination rate in the recovered F'e304 in a portion of the filter is 24.4% compared to the control 75. It also flows out into the processing liquid sent to line 18 in FIG.
The SS improved to 756 points compared to the control 25.0%.

That is, by using ultrasonic waves, the purity of Fe3O4 recovered to line 23 in Figure 1 increases, and the content of SO (red tide plankton) recovered to line 1B increases. It is.

(b) Water quality or substance amount of the slurry in line 11/16 in Figure 1 (b) Water quality or substance amount in the slurry exiting line 18 in Figure 1 0) Water quality or substance amount in the slurry in line 26 in Figure 1 Substance amount T S B : Total of Fe3O4 and S S filS
S; red tide plankton

[Brief explanation of the drawing]

FIG. 1 shows a flow chart according to an embodiment of the present invention, and FIG. 2 shows a schematic diagram of a magnetic filter used in FIG. 1 at a glance. 1 person included as a second substitute 1) Meifuku agent Ryo Hagiwara -

Claims (1)

[Claims] Red tide-like raw water is taken from a water area, and ferromagnetic fine particles are added to form aggregates or floc-like particles in which red tide plankton and ferromagnetic fine particles are entangled to strengthen the red tide plankton from the red tide-like raw water. In the method of recovering a concentrated state together with magnetic fine particles, the concentrate is subjected to ultrasonic treatment, and then water is passed through a magnetic filter to obtain a slurry with a high content of red tide plankton and a high content of ferromagnetic fine particles. A method for treating red tide characterized by separating it into a slurry and collecting it separately.