JPH0471696A - Method for purifying water - Google Patents

Abstract

PURPOSE:To simply purify water at a low cost by adding photosynthesis bacteria to a water region to be purified, setting a light source within 20 m from the region and irradiating the region with light. CONSTITUTION:Photosynthesis bacteria are added to a water region to be purified, at least one light source ensuring >=50 luxes is set within 20 m from the region and the region is irradiated with light for >=2 hr/day in the night. The amt. of dissolved oxygen in the water is increased, org. matter is actively degraded or metabolized by aerobic bacteria and other organisms and the purification of the water proceeds. By this method, the water in a large water region such as a pond, lake or marsh can simply be purified at a low cost.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a water purification method for ponds, fish farms, lakes, etc.

[Conventional technology] Water areas with low water turnover, such as reservoir ponds, fish farms, lakes, etc.
Particularly in these deep layers, water quality is decreasing due to a lack of oxygen in the water, a decline in the ability of aerobic bacteria to decompose organic matter, and progress to siltation of the bottom.

The aforementioned deterioration in water quality is a sanitary problem and also causes a poor appearance, so to prevent this, for example, water replacement, cleaning, and spraying of chemicals are carried out.

[Problems to be Solved by the Invention] However, in large lakes and ponds, operations such as water replacement and cleaning require labor and expense, and are economically problematic to perform on a regular basis.

In addition, many chemical agents are highly dangerous due to their toxicity and are difficult to decompose, and in the worst case scenario, they can kill microorganisms in the water and change the aquatic ecosystem.

As described above, there is currently a demand for a low-cost and simple water purification method.

[Means for Solving the Problems] The present invention solves the above problems and provides a low-cost and simple water purification method.

That is, the present invention is a patented method characterized by adding photosynthetic bacteria to a targeted purified water area, installing a light source within 20 m, and irradiating the purified water area with light.

Hereinafter, the configuration of the present invention will be explained in detail.

Purified water areas using the water purification method of the present invention include ponds, fish farms,
Lakes and marshes, for example, BOD (Bi.

Chemical Oxygen Demand:
Biochemical oxygen demand) and COD (Chemical
Oxygen Demand: chemical oxygen demand)
It is a body of water with a high value of

The photosynthetic bacteria used in the present invention are, for example, Rhodopseudomonas (
rhodospiral 1 aceae of the genus Rhodopseudomonas,
Chromatiasis (chr.

matiaceae), chlorobiaceae
obiaceae) + capsula
ta), chromatium, gelatinosa, and the purple sulfur bacterium thiocapsa. Preferably, combinations of turnipulata and chromatium, or combinations of gelatinosa and thiocapsa are used. This method is preferable because organic acids, which are BOD sources, and highly toxic hydrogen sulfide can be removed at the same time. Furthermore, a combination of photosynthetic bacteria and other bacteria is more preferable in terms of decomposing and purifying accumulated organic sludge; specifically, a combination of photosynthetic bacteria and non-photosynthetic bacteria Bacillus megaterium (Bacillus megaterium) is preferable.
It is desirable to use a combination of smegaterium. The amount of these fungi added varies depending on the type of fungi, the volume of the purified water area, and the water quality, but is preferably 10/day/ton or more (dry weight of bacteria/volume of the purified water area). Add these to the purified water area as evenly as possible.

Next, since the light source used in the present invention functions as sunlight, its wavelength must be 300 to 900 nm, or at least 500 to 800 nm.

In the present invention, the installation location of the light source is within 20 m from the purified water area, and the purified water area here refers to the entire aquatic area for the purpose of purification. (Conversely, if the water quality is low and transparency is low, the amount of light irradiated into the water will decrease due to the reflection of light on the water surface, so install it underwater, that is, in a purified water area.) It is preferable to do so.

The intensity of the light source varies depending on the water quality of the purified water area, but it must be at least 50 lux. The 50 lux here refers to the illuminance at the position closest to the light source, and if the light source is placed underwater, the water will come into direct contact with the light source, so cover the part of the light source that emits light. Refers to the illuminance on a transparent member. If the clarity of the water in the purified water area is extremely low, the light will need to reach the entire area, especially the interior (so it is best to install multiple light sources and change the installation locations as appropriate as the purification progresses.

In the present invention, the light irradiation time is at least at night when no sunlight is irradiated, but the irradiation is also carried out appropriately during bad weather or when the illuminance of sunlight on the purified water area is less than 50 lux, such as just before sunset. The irradiation time varies depending on seasonal changes in sunlight hours and the weather, but it is necessary to irradiate for at least 2 hours a day, preferably for 6 hours or more. Irradiation of light may be continuous or intermittent.

[Function] Fungi such as photosynthetic bacteria, single-celled organisms such as blue-green algae, protozoa, diatoms, and green algae that live in water are active during the day when there is light, and their metabolic activities progress in water purification. .

However, at night when there is no light or when the weather is bad (daytime when the amount of light irradiation is low), metabolic activity weakens and purification does not proceed.

Moreover, since photosynthetic bacteria, single cells such as blue-green algae, and green algae no longer perform photosynthesis, no oxygen is generated, and the amount of dissolved oxygen in the water decreases. Therefore, in water areas that are not exposed to sunlight even during the day or water areas that have little water turnover, the amount of dissolved oxygen is extremely low, and the above biological systems, especially aerobic bacteria, do not decompose and metabolize organic matter, which accumulates as pollutants and accumulates in water. The organisms that carry out the purification process are also decreasing in number.

In the present invention, photosynthetic bacteria are first added to water bodies with reduced water quality, and then artificial lighting is applied at night or during bad weather to increase the light irradiation time and promote photosynthesis. As a result, the amount of dissolved oxygen in the water increases, the decomposition and metabolism of organic matter by aerobic bacteria and other organisms becomes active, and water purification progresses.

[Examples] Specific embodiments of the present invention will be shown below through Examples, but the present invention is not limited thereto.

Comparative Example 1 Area at average water level: 400 m2. Deepest part 2m, volume 550
On the bottom of Rho's pond, there was mud 10 cm thick. Nine light sources were installed so that the entire water surface of this pond was irradiated with 500 lux of light, and the light was irradiated for 6 hours a day. Although observation was continued for 5 weeks, there was almost no change in water quality.

Comparative Example 2 The light source of the pond in Comparative Example 1 was removed, and 500 g of the photosynthetic bacterium Rhodopseudomonas gelatinosa (dry weight) was sprinkled over the entire water surface, and changes in water quality were observed. However, no change in water quality was observed even after 5 weeks had passed.

Example 1 The same light source as in Comparative Example 1 was installed in the pond of Comparative Example 2, and light was irradiated in the same manner. As a result, sludge started to decrease after 3 weeks.
Water clarity has also improved. Further observation revealed that the sludge had almost disappeared after 10 weeks, so we continued to observe the water quality by reducing the number of light sources and setting the light to 200 lux above the water surface, but no sludge was generated (and the water quality was It remained in good condition.

Example 2 In a pond with almost the same volume as in Example 1 and with similar water pollution conditions, 100 g of the photosynthetic bacterium Rhodopseudomonas bushulata and 100 g of Chromatium (dry weight) were distributed evenly over the entire water surface ( When irradiated with light in the same manner as in Example 1, the sludge began to decrease after 7 days, and after 3 weeks, there was no sludge at all, and the water was almost completely turbid.

[Effects of the Invention] As explained above, according to the water purification method of the present invention, water in large-scale water bodies such as ponds and lakes can be easily and inexpensively purified. Moreover, after water has been purified using the water purification method of the present invention, simply by irradiating it with light as appropriate, water purification by organisms in the water will be promoted, so there is no need to worry about water quality deteriorating (very economical). It is true.

Applicant: Yoshida Research Institute Co., Ltd.

Claims (2)

[Claims] (1) Water characterized by adding photosynthetic bacteria to the purified water area, and installing at least one light source of 50 lux or more within 20 m from the purified water area, and irradiating the water with light for at least 2 hours/day at least at night. Purification method. (2) The water purification method according to claim (1), wherein the wavelength of the irradiated light is 300 to 900 nm.