JPH11104676A - Facility for purifying lake, marsh, and others and method for purifying eutrophic water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce additional facilities for purifying eutrophic water by using a lake, a marsh, and others by a method in which raw water is allowed to flow into an upper opening enclosed by a frame-shaped structure floating on the water surface of a lake, a marsh, or the like and to contact an algae- adhesion body supported by a screen, and nutrients are removed by the algae. SOLUTION: When a purification facility 1 connected with a raw water supply means is arranged in a necessary place of a lake or a marsh A, raw water W supplied from an inflow pipe 7 into an upper opening 3 is stored in a frame-shaped structure 2. By microorganisms such as algae adhering to an algae-adhesion body 6 and growing, organic substances and nutritious salts of phosphorus, nitrogen, and others contained in the raw water W are removed, and new raw water W is supplied in sequence so that the purified water descends and, after algae and others being filtered by the body 6, is combined with water of a lake or a marsh through a screen 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facility for purifying lakes and marshes and a method for purifying eutrophic water.
The present invention relates to a technology for removing nutrients such as phosphorus to prevent eutrophication of lakes and marshes.

[0002]

2. Description of the Related Art The following methods have been tried as a purification technique for lakes and marshes. (1) Technology for collecting eutrophic water, such as domestic wastewater and industrial wastewater, at a sewage treatment plant to remove eutrophication-causing substances such as organic matter, nitrogen, and phosphorus, and then discharging it downstream. (2) Technology for removing eutrophication-causing substances by floating aquatic plants such as water hyacinth on the water surface of lakes and marshes. (3) A technology that suppresses the growth of plankton by pumping low-temperature water from the bottom of lakes and marshes to the surface of water and lowering the temperature of the surface. (4) Technology disclosed in Japanese Patent Application Laid-Open No. 9-192689 "Apparatus and method for preventing eutrophication of water areas": In other words, a pool-shaped reactor is floated on a lake or the like, and drainage (water to be treated) is horizontally placed. A technology that allows the aquatic plants and algae in the reactor to absorb eutrophication while flowing.

[0003]

However, (1) and (2)
The technique (3) is not practical because it requires a large-scale facility, increases processing costs, and impairs economic efficiency. In the technique (4), the water to be treated is moved horizontally, so that the aquatic plants and algae in the reactor tend to be deviated, and the flow is uneven, so that it is difficult to increase the purification rate.

[0004] The present invention has been made in view of the above circumstances, and achieves the following objects. Use of lakes and marshes to reduce the need for additional facilities for purifying eutrophic water, eliminate the need for land sites, and facilitate installation space. Efficient removal of eutrophication-causing substances such as phosphorus and nitrogen. Prevent breeding algae from becoming a source of contamination. Reducing restrictions on purification sites and increasing the arbitrariness of installation. Providing a breeding environment for fish and the like. Use of gravity eliminates the need for a power source, etc., and enhances versatility.

[0005]

Means for Solving the Problems A framework in which eutrophic water (water to be treated) flowing into a lake or the like having an open water surface is floated on the surface of a lake or the like by using a head or the like. Flowing into the upper opening surrounded by the frame-like structure, the eutrophic water to be treated is brought into contact with the algae adherent supported by the screen provided in the frame-like structure, A technology that purifies the water to be treated by removing nutrients with algae growing on the surface of the body, removes nutrients, drains the water to be treated downward from the screen, and joins the lake water etc. Is done. The frame-like structure is provided with a float portion for disposing it in a state of floating on the surface of a lake or the like, and the frame-like structure is configured by a pipe-like body having the float portion. Technology is also adopted. As the screen, a technology having a coarse lattice portion and a net portion on which a weight is supported and a granular algae adherent is laminated on the lattice portion is also applied. River water, sewage treatment water,
An inflow pipe is provided for supplying the water to be treated including any of the septic tank effluent, agricultural wastewater, and factory wastewater, and the water to be treated is caused to flow down from the inflow pipe and supplied to the algae adherent. The water to be treated is
Algae adhering body, guided downward sequentially through the screen,
It flows out of the screen and joins the lake water.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a purification system for lakes and marshes and a method for purifying eutrophic water according to the present invention will be described.
This will be described with reference to FIGS.

[0007] In the figure, reference symbol A is a lake, L is the water surface, X is the treated water supply means, W is the treated water (eutrophic water, inflow water), 1
Denotes a purification facility, 2 denotes a frame-like structure, 3 denotes an upper opening, 4 denotes a float, 5 denotes a screen, 6 denotes an algal adherent, and 7 denotes an inflow pipe.

[0008] The lake A has an open water surface L to which sunlight is irradiated, and is intended for purification in a place where the sun shines.
If it has, other than the lakes and marshes that are the normal inland waters,
Includes rivers, irrigation ponds, artificial rivers, irrigation canals, intakes, drains and sea levels.

The treated water supply means X includes a treated water W
Flows into the above-mentioned lakes and marshes via the inflow pipe 7, and usually, any of river water, sewage treatment water, septic tank effluent, agricultural effluent, factory effluent, etc. which flows into the above-mentioned lakes and marshes Alternatively, a technique of forcibly sending the mixed water or the like using, for example, a pump is applied. It should be noted that this does not exclude a technique of simply flowing down using a head.

As shown in FIGS. 1 and 2, the purification equipment 1 is a frame-like structure which is arranged in a state of being immersed in a water surface L of a lake A and, for example, in a state where a plurality of units are interconnected and moored. 2, an upper opening 3 surrounded by the frame-shaped structure 2 and formed to face upward, and a float portion 4 arranged in the frame-shaped structure 2 to generate buoyancy as a whole.
And a screen 5 arranged in the frame-shaped structure 2 so as to be divided into upper and lower portions, and an algal attachment body 6 supported by the screen 5.

The frame-like structure 2 is made of, for example, plastic or stainless steel. In the examples shown in FIGS. 1 and 2, the square frame is formed integrally with a float portion 4 having a hollow square hole to generate buoyancy. The buoyancy is set so that it floats horizontally with respect to the water surface L, and at least half of the total height is submerged.

The screen 5 is disposed inside the frame-like structure 2 so as to partition the screen vertically, as shown in FIG.
A lattice portion 5a which is attached to the lower portion or near the bottom portion of the frame-shaped structure 2 and has a relatively coarse mesh or slit, and supports the weight of the algal attached body 6 disposed above the lattice portion 5a; The net portion 5b has meshes and meshes that cover the top and suppress the falling of the algae-adhered material 6 that is granular.

The algae-attached body 6 is a granular porous body or gravel. The algae-attached body 6 is laid on the net portion 5b of the screen 5 so as to form a layer (thickness) and has a function of algae attachment and filtration. In the breeding of algae, the treated water W after purification
Is allowed to flow downward.

As shown in FIG. 1, the inflow pipe 7 is connected to the water-to-be-treated supply means X, and its leading end opening is inserted into the upper opening 3 so that the water-to-be-treated water supply means X is operated. The water to be treated W is supplied to the algae adherent 6 on the screen 5 by the above-mentioned pump. In addition, as described above, when a head can be used, it is possible to simply flow down without using a pump.

Further, as the algae to be attached to the algae attached body 6, attached algae such as blue spider and diatom are selected. The reason is that the growth rate is high, the ability to absorb nutrients is high, for example, about 10 times that of aquatic plants, the ability to separate and remove from water is good, the nutritional value is high, and fish,
It is a good feed for chickens and livestock.

If the purification facility 1 is connected to the treated water supply means X at a required location in the lake A,
Treated water W sent from the inflow pipe 7 to the upper opening 3
Is stored in a state of being spread horizontally inside the frame-shaped structure 2 and is contained in the water to be treated W by microorganisms such as algae that are growing by attaching to the algae attached body 6. The organic matter and nutrients such as phosphorus and nitrogen are removed, and the freshly treated water W is sequentially sent in. As a result, the purified water to be treated W descends, and the algae and the like are filtered by the algae attached body 6. Thereafter, as shown by the arrows in FIG. 1, the water is merged with the water of the lake A (lake water) via the screen 5.

As described above, a sufficient amount of sunlight is radiated through the upper opening 3 at the portion of the algae attached body 6, and in addition to the fact that the water to be treated W is eutrophic water. Algae proliferate, increasing the ability to absorb nutrients,
Good separation and removal properties from the water to be treated W are achieved.

When the amount of the algae that has propagated at the portion of the algae attachment 6 increases, or
In the case where gas is generated due to an increase in thickness and diffusion of oxygen is deteriorated, or when algae are separated from the surface of gravel due to gas generation during photosynthesis, these algae float on the water W to be treated. It is integrated in the upper opening 3. The algae in the accumulated state are removed from the upper opening 3.

When the water level L of the lake A rises due to heavy rain or the like, or when the water level L drops during drought, the frame-like structure 2 in the purification facility 1 moves up and down following the rise and fall of the water level L. Therefore, the relationship between the water surface L and the algae attached body 6 becomes substantially constant, and the purification function is maintained.

Next, when the amount of the water to be treated W supplied via the inflow pipe 7 is increased or decreased, when a large amount of the water to be treated W flows into the purification facility 1 during rainfall or the like, the screen 5 As the amount of water passing through increases, and the descending speed of the water to be treated W increases, the contact time with the algae attached body 6 decreases, and as a result,
Although the algae do not sufficiently absorb and remove nutrients and the like, the water W to be treated is merged with lake water, etc., but during rainfall, etc., the concentration of nutrients and the like becomes low due to rainwater mixing. , The effect is reduced. When the amount of water W to be treated flowing into the purification equipment 1 becomes small, for example, during a drought,
As the amount of water passing through the screen 5 decreases and the descending speed of the water to be treated W decreases, the contact time with the algae attached body 6 increases, and as a result, the algae and the like sufficiently remove nutrients and the like. After being absorbed and removed, the purified water W is merged with lake water.

[Other Embodiments] The present invention includes the following techniques. a) Forming the frame-shaped structure 2 and the float portion 4 separately, for example, arranging an arbitrary number of float portions 4 around the frame-shaped structure 2. b) A part of the peripheral wall of the frame-shaped structure 2 partially includes the water W to be treated.
To form slits and holes that allow inflow of water. c) A pump or the like that forcibly pumps the water to be treated W is added to the inside of the frame-shaped structure 2. d) When the treated water supply means X is factory drainage or the like, and a large step can be taken between lakes and marshes and drains, etc., the purification equipment 1 is interposed in the middle without floating on the water surface. To distribute. e) When there are rivers into which eutrophic water flows into lakes, etc.,
Disposing an inlet for the water to be treated, for example, by making a cutout on the upstream side of the frame-like structure 2, guiding the water to be treated into the inside of the frame-like structure to purify the water.

[0022]

According to the purification equipment for lakes and marshes and the method for purifying eutrophic water according to the present invention, the following effects can be obtained. (1) The water to be treated is allowed to flow into an upper opening surrounded by a frame-like structure such as a state of being floated on the surface of water, and the water to be treated in a eutrophic state is applied to an algal adherent supported by a screen. By contacting and removing nutrients with algae, utilization of lakes and marshes can be facilitated, and addition of facilities for purifying eutrophic water can be reduced. (2) With the above, land sites are not required,
The installation space can be easily secured, and cost reduction can be achieved. (3) While purifying the water to be treated downward, purify it with algae, remove nutrients, and then drain the water downward, allowing it to slowly come into contact with the algae over a large area to cause eutrophication of phosphorus, nitrogen, etc. Substances can be removed efficiently. (4) The water to be treated is caused to flow down to the algae attached body using a head and gravity, and the nutrients are removed by the algae, so that the water to be treated can be purified without the need for a power source and the like. The range can be expanded to increase versatility. (5) By arranging the frame-like structure in a state of being floated on the water surface by the float part, the influence of the water level of the lake water is reduced, and the influence of the upper and lower water levels is reduced, thereby purifying the water to be treated. It can always be performed in a stable state. (6) By using a coarse-grained grid portion and a fine-grained net portion as a screen, the filterability of the propagated algae is increased, the algae are prevented from becoming a pollution source, and the algae collected from the screen are removed. Can be used for compost, feed, fuel and the like. (7) It is possible to provide a breeding environment for fish and the like by suppressing abnormal growth of plankton such as lakes and marshes, while creating shade.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a first embodiment of a purification facility for lakes and marshes and a method for purifying eutrophic water according to the present invention.

FIG. 2 is a partially broken plan view showing a first embodiment of a purification facility for lakes and marshes and a method for purifying eutrophic water according to the present invention.

[Explanation of symbols]

 A Lake / Lamp L Water surface X Treated water supply means W Treated water (eutrophic water, influent water) 1 Purification equipment 2 Frame structure 3 Upper opening 4 Float 5 Screen 5a Lattice 5b Net 6 Algae deposit 7 Inflow pipe

Claims (8)

[Claims] 1. A frame-shaped structure (2) having an upper opening (3) to which water to be treated (W) is supplied, and an algae adhered body (6) arranged on the frame-shaped structure and supported. A purification facility for lakes and marshes, comprising: a screen (5) for causing water to be treated, which has been purified by algae attached to the algae adherent, to flow downward. 2. The frame-like structure (2) is provided with a float (4) for arranging the frame-like structure in a state of being floated on the surface of a lake or the like. Purification equipment for lakes and marshes. 3. The frame-like structure (2) includes a float portion (4).
3. The facility for purifying lakes and marshes according to claim 2, wherein the facility is constituted by a pipe-shaped body having: 4. The screen (5) has a coarse grid portion (5a) and a net portion (5b) on which a weight is supported and a particulate algae adherent (6) is laminated. The facility for purifying lakes and marshes according to claim 1, 2 or 3. 5. An inflow pipe (7) for supplying to-be-processed water (W) including any of river water, sewage treatment water, septic tank effluent, agricultural wastewater, and factory wastewater is disposed in the upper opening (3). The purification facility for lakes and marshes according to claim 1, 2, 3, or 4, wherein the purification is performed. 6. The eutrophic water to be treated (W) flows into the upper opening (3) of the frame-like structure (2) and is supported by a screen (5) arranged in the frame-like structure. A method for purifying eutrophic water, comprising removing nutrients by contact with algae that have been removed and then draining the same downward through a screen. 7. The frame-like structure (2) is placed on a water surface (L) of a lake or the like.
7. The method for purifying eutrophic water according to claim 6, wherein the nutrients in the water to be treated (W) are removed while floating. 8. The method for purifying eutrophic water according to claim 6, wherein the water to be treated (W) is supplied to the upper opening 3 using a head.