【０００１】
【発明の属する技術分野】
この発明は、例えば、ダム、湖、湖沼、貯水池、溜め池などの閉鎖性水域の淡水又は海水などの水質浄化を図る技術に係り、特に、閉鎖性水域の最深部の水を排水通路を用いて水面上に強制的に排出して大気中の酸素と接触させて閉鎖性水域内に戻すことにより、低コストで閉鎖性水域全体の淡水又は海水などの水に万遍なく酸素を溶解させて貧酸素状態を解消し、酸素を利用して水質浄化を図る閉鎖性水域の水質浄化方法に関するものである。
【０００２】
【従来の技術】
従来、例えば、ダム、湖、湖沼、貯水池、溜め池などの閉鎖性水域では、淡水又は海水などの水の流れが殆どないため、酸素が十分に水面下方の水中及び水底側に供給されず、その結果、中層以下に貧酸素又は無酸素状態が出現する。このため、例えば、曝気装置、撹拌装置、酸素供給ポンプなどを使用して、水中に酸素を供給して水の浄化を図る技術が知られており、その一部は実用化されている。
【０００３】
【発明が解決しようとする課題】
しかしながら、従来の曝気装置、撹拌装置、酸素供給ポンプなどの装置を用いて、閉鎖性水域の淡水中又は海水中に空気又は酸素を供給して水の浄化を図る技術においては、装置が大型となったり、構造が複雑で、消費エネルギーが大きく、その結果、コストがかかり過ぎて、コスト面で非常に効率が悪いという問題があった。
【０００４】
この発明は、上記のような課題に鑑み、その課題を解決すべく創案されたものであって、その目的とするところは、冷たく比重の大きい水は高い場所から低い場所に水平方向へも拡散しながら落下する現象及び酸素の少ない水は水面上で酸素を効率的に吸収できる性質を利用して、冷たく酸素の少ない最深部の水を強制的に水面上に排出して、水面で大気中の酸素に接触させ、酸素が溶解した水を水中に落下拡散させ、閉鎖性水域全体に酸素を豊富に含んだ水を万遍なく行き渡らせて、省エネルギーで閉鎖性水域全体、特に底層への酸素供給により水質浄化を図ることのできる閉鎖性水域の水質浄化方法を提供することにある。
【０００５】
【課題を解決するための手段】
以上の目的を達成するために、請求項１の発明は、淡水又は海水の閉鎖性水域の最深部と水面との間に排水通路を配設し、閉鎖性水域の最深部の水を排水通路を通じて水面上に強制的に排出して大気中の酸素と接触させて酸素を取り込み、又最深部の比重の大きい水の落下現象を利用し、最深部から水面、水面から最深部に向けての閉鎖性水域全体に上下の対流を生じさせ、大気中の酸素と接触して酸素が溶解した水面水を最深部に向けて連続的に移動循環させることで、閉鎖性水域の貧酸素状態の水を酸素を豊富に含んだ水に置き換えて、閉鎖性水域全体に酸素を豊富に含んだ水を万遍なく行き渡らせ、酸素を利用して閉鎖性水域全体の水質浄化を図る手段よりなるものである。
【０００６】
また、請求項２の発明は、淡水又は海水の閉鎖性水域の水底に凹穴部を形成して最深部を設け、閉鎖性水域の水底側を最深部に向かって連続的に深くして流水状に形成すると共に、淡水又は海水の閉鎖性水域の最深部と水面との間に排水通路を配設し、閉鎖性水域の最深部の水を排水通路を通じて水面上に強制的に排出して大気中の酸素と接触させて酸素を取り込み、又最深部の比重の大きい水の落下現象を利用し、最深部から水面、水面から最深部に向けての閉鎖性水域全体に上下の対流を生じさせ、大気中の酸素と接触して酸素が溶解した水面水を最深部に向けて連続的に移動循環させることで、閉鎖性水域の貧酸素状態の水を酸素を豊富に含んだ水に置き換えて、閉鎖性水域全体に酸素を豊富に含んだ水を万遍なく行き渡らせ、酸素を利用して閉鎖性水域全体の水質浄化を図る手段よりなるものである。
【０００７】
【発明の実施の形態】
以下、図面に記載の発明の実施の形態に基づいて、この発明をより具体的に説明する。
ここで、図１は閉鎖性水域の水質浄化方法の概念図、図２は排水装置の側面図、図３は排水装置の平面図である。
【０００８】
図において、淡水又は海水の閉鎖性水域ａの水質浄化に使用する閉鎖性水域水質浄化装置１は、淡水又は海水の閉鎖性水域ａの最深部２と水面３との間に配設された排水通路４としての排水ホース４１、閉鎖性水域ａの最深部２の水を排水通路４を通じて水面３上に強制的に排出する排水装置５から構成される。
【０００９】
閉鎖性水域ａの最深部２は、閉鎖性水域ａで最も深い水底であり、天然状態で存在する場合にその箇所を利用する。また、閉鎖性水域ａの水底は、最深部２に向かって連続的に深くなっていて、水が水底に沿って自然に流れて最深部２に集まるような流水状の地形になっているのが望まれる。
【００１０】
天然状態で閉鎖性水域ａの最深部２が特定できない場合には、閉鎖性水域ａの水底に周囲よりも最も深い凹穴を形成して最深部２を人工的に設ける。また、閉鎖性水域ａの水底が天然状態で凹凸状態にある場合には、閉鎖性水域ａの水底の地形を最深部２に向かって連続的に深くなるように形成し、水が底面に沿って自然に流れて最深部２に集まるような流水状の地形に形成する。
【００１１】
排水通路４としての排水ホース４１は、その下端が閉鎖性水域ａの最深部２に配置されていて、最深部２に移動してきた水を排水ホース４１を通じて取り入れることができるようになっている。排水ホース４１の上端は水面３上に設けられた排水装置５のダクト５１に接続されている。排水ホース４１には柔軟性のあるホースが使用され、閉鎖性水域ａの水位変動に対して柔軟に対応して負荷が作用しにくい構造になっている。
【００１２】
排水装置５は、排水通路４としての排水ホース４１を通じて最深部２に移動してきた水を強制的に水面３上に排出する装置で、排水ホース４１に連結するダクト５１、ダクト５１の上部に取り付けられた軸流ポンプ５２、排水装置５を水面３上に浮かべるフロート５３などから構成されている。
【００１３】
ダクト５１は上下向きに配置され、上下向きのダクト５１は下部が円筒形に形成され、その下端には前記排水ホース４１の上端が接続され、上部には軸流ポンプ５２が配置されている。ダクト５１は排水ホース４１を通じて吸い上げられた水を水面３上に排出する出口側となる。
【００１４】
軸流ポンプ５２は、排水ホース４１を通じて最深部２の水を強制的に汲み上げるもので、回転して水を汲み上げるプロペラ５２ａ、プロペラ５２ａの回転軸となるシャフト５２ｂ、及びシャフト５２ｂを通じてプロペラ５２ａを回転させるモーター５２ｃから構成される。モーター５２ｃは、モーター収容ケース５４に収容されている。
【００１５】
プロペラ５２ａは上下向きに配置されたシャフト５２ｂの下端に取り付けられており、下端にプロペラ５２ａを取り付けたシャフト５２ｂの上端はその上部に配置されたモーター５２ｃに連動連結されている。
【００１６】
フロート５３は、排水装置５を水面３上に浮かべる機能を果たすもので、モーター収容ケース５４の外周側にこの実施の形態では４個取り付けられている。各フロート５３はダクト５１の上端から最深部２の水を排出する際に妨げとならないように、それぞれ間隔をあけてモーター収容ケース５４の外周回りに取り付けられている。
【００１７】
次に、上記発明の実施の形態の構成に基づく作用について以下説明する。
例えば、ダム、湖、湖沼、貯水池、溜め池などの閉鎖性水域ａの汚れた淡水又は海水などの水を浄化するために、閉鎖性水域ａの最も深い最深部２の上方の水面３上に閉鎖性水域水質浄化装置１の排水装置５を曳航し、排水装置５のダクト５１の下端に接続された排水通路４としての排水ホース４１の下端を最深部２に下ろす。
【００１８】
水面３上の排水装置５は水流や風などによって簡単に流れないように、係留ロープなどを使用して最深部２の上方の水面３上に係留する。また、排水ホース４１の下端には、ゴミの吸引を防ぐストレーナーが付けられている。これは重くなるように金属で製作し排水ホース４１の移動防止の役目を果たしている。
【００１９】
この発明に係る閉鎖性水域ａの水質浄化方法が適用される閉鎖性水域ａの水底は、最深部２に向かって連続的に深くなっていて、水が水底に沿って自然に流れて最深部２に集まるような流水状の地形になっているのが望まれる。
【００２０】
また、閉鎖性水域ａの水底に天然の最深部２が存在しない場合や水底の凹凸が激しい場合には事前に土木作業などによって、水底に凹穴部を形成して最深部２を人工的に設けたり、閉鎖性水域ａの水底の地形を最深部２に向かって連続的に深くなるように形成し、水が底面に沿って自然に流れて最深部２に集まるような流水状の地形に形成する。
【００２１】
以上のようにして、閉鎖性水域水質浄化装置１の排水通路４としての排水ホース４１と排水装置５を淡水又は海水の閉鎖性水域ａに設置した後に、排水装置５の軸流ポンプ５２を作動させる。軸流ポンプ５２のモーター５２ｃが作動すると、モーター５２ｃに連動連結されたシャフト５２ｂの下端に取り付けられたプロペラ５２ａが一定方向回りつまり水を汲み上げる方向に回転する。
【００２２】
軸流ポンプ５２のプロペラ５２ａが回転すると、ダクト５１及び排水通路４としての排水ホース４１の内部には上方に向かって上昇流が生じて、排水ホース４１の下端の最深部２の貧酸素状態の水は排水ホース４１内に吸引されてその内部を上昇し排水ホース４１の上端が接続されたダクト５１の上端から水面３上に排出される。
【００２３】
最深部２の貧酸素状態の水は、水面３上に排出される際に大気中の酸素に接触して、大気中の酸素が貧酸素状態の水に溶解して酸素を豊富に含んだに水になる。また、このとき、最深部２の水温の低い水は水面３上で太陽光などによって暖められて水温はやや上昇する。
【００２４】
閉鎖性水域ａの最深部２では連続的に水が水面３上に排出されるために、その周囲の水が最深部２に向かって移動する。このため。閉鎖性水域ａの水面３と最深部２との間では、上下方向に対流が生じる。つまり、最深部２及び排水通路４としての排水ホース４１及びダクト５１を通じて上昇流が生じ、排水通路４の周囲では水面３全体から最深部２に向かって下降流が生じる。
【００２５】
この下降流に沿って水面３全体から下側の最深部２に向かって移動する水には酸素が豊富に含まれているために、閉鎖性水域ａ全体の水は、時間と共に水面３の表面全体から下側に向かって徐々に酸素が豊富に含まれた水と置き換えられて行く。
【００２６】
同様に、この酸素が含まれた水は太陽光によって暖められて水温が高いために、閉鎖性水域ａ全体の水は、時間と共に水面３の表面全体から下側に向かって徐々に水温の高い水と置き換えられて行く。
【００２７】
このようにして、閉鎖性水域ａの貧酸素状態の水は、酸素を豊富に含んだ水に置き換えられて、閉鎖性水域ａ全体に酸素を豊富に含んだ水を万遍なく行き渡らせることができ、これにより、酸素を利用して閉鎖性水域ａ全体の水質の浄化を図ることができる。
【００２８】
【実験例】
実験は、閉鎖性水域ａとして図４に示す佐賀県多久市の天ヶ瀬ダムで行った。図５〜図８に装置設置前の昨年（２００１年）７月、９月と装置設置後の今年（２００２年）７月、９月の溶存酸素、水温、全リン、ＣＯＤ（化学的酸素要求量）のデータを比較する。
図５では昨年存在していた中層以下の無酸素状態が完全に消滅していることを示す。図６では水温が低層から上層までほぼ均一化していることを示す。また、図７では、無酸素状態の解消に伴い水底部の泥からのリンの溶出が抑制され、昨年に比べ水中の全リンが低下していることを示している。図８では、ＣＯＤの値の改善が行われたことを示している。
【００２９】
なお、この発明は上記発明の実施の形態に限定されるものではなく、この発明の精神を逸脱しない範囲で種々の改変をなし得ることは勿論である。
【００３０】
【発明の効果】
以上の記載より明らかなように、請求項１、請求項２の発明に係る閉鎖性水域の水質浄化方法によれば、冷たく比重の大きい水は高い場所から低い場所に水平方向へも拡散しながら落下する現象及び酸素の少ない水は水面上で酸素を効率的に吸収できる性質を利用して、冷たく酸素の少ない最深部の水を強制的に水面上に排出して、水面で大気中の酸素に接触させ、酸素が溶解した水を水中に落下拡散させ、閉鎖性水域全体に酸素を豊富に含んだ水を万遍なく行き渡らせて、省エネルギーで閉鎖性水域全体、特に底層への酸素供給により水質浄化を図ることができる。そのうえ、これを達成するに当たり、最深部と水面との間に配置した排水通路と、最深部の水を排水通路を通じて水面に強制的に排出する排水装置のみの、非常に簡単な構造で、しかも、そのランニングコストも非常に低コストで実現することができる。
また、上記の効果に加えて、閉鎖性水域全体の水温も略均一にすることができ、特に底層の低水温部分の水温を高くすることができる等、極めて新規的有益なる効果を奏するものである。
【図面の簡単な説明】
【図１】この発明の実施の形態を示す閉鎖性水域の水質浄化方法の概念図である。
【図２】この発明の実施の形態を示す排水装置の側面図である。
【図３】この発明の実施の形態を示す排水装置の平面図である。
【図４】実験場所の平面図である。
【図５】溶存酸素量改善の実験前後の結果を示す図である。
【図６】水温改善の実験前後の結果を示す図である。
【図７】全リン改善の実験前後の結果を示す図である。
【図８】ＣＯＤ（化学的酸素要求量）改善の実験前後の結果を示す図である。
【符号の説明】
１ 閉鎖性水域水質浄化装置
２ 最深部
３ 水面
４ 排水通路
４１ 排水ホース
５ 排水装置
５１ ダクト
５２ 軸流ポンプ
５２ａ プロペラ
５２ｂ シャフト
５２ｃ モーター
５３ フロート
５４ モーター収容ケース
ａ 閉鎖性水域[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for purifying fresh water or seawater in closed water areas such as dams, lakes, lakes and marshes, reservoirs, reservoirs, and the like.In particular, the present invention uses a drainage passage for the deepest water in closed water areas. By forcibly discharging the water onto the surface of the water and bringing it into contact with the oxygen in the atmosphere and returning it to the closed water area, oxygen can be uniformly dissolved in fresh water or seawater in the entire closed water area at low cost. The present invention relates to a method for purifying water quality in a closed water body, which eliminates anoxic condition and purifies water using oxygen.
[0002]
[Prior art]
Conventionally, for example, in closed water bodies such as dams, lakes, lakes and marshes, reservoirs, and reservoirs, since there is almost no flow of water such as freshwater or seawater, oxygen is not sufficiently supplied to the water below the water surface and to the bottom of the water, As a result, an anoxic or anoxic state appears below the middle layer. For this reason, a technique for purifying water by supplying oxygen into water using, for example, an aerator, a stirrer, an oxygen supply pump, or the like is known, and some of the techniques have been put to practical use.
[0003]
[Problems to be solved by the invention]
However, in a technology for purifying water by supplying air or oxygen to fresh water or seawater in a closed water area using a conventional aeration device, a stirring device, an oxygen supply pump or the like, the device is large. In addition, there is a problem that the structure is complicated, the energy consumption is large, and as a result, the cost is too high and the cost is very inefficient.
[0004]
The present invention has been made in view of the above problems, and has been made in order to solve the problems. The purpose of the present invention is to diffuse cold, high-density water horizontally from a high place to a low place. By taking advantage of the phenomenon of falling while water and the low oxygen content of water can absorb oxygen efficiently on the water surface, the deepest water, which is cold and low in oxygen, is forcibly discharged onto the water surface, and the water surface contains air. Water, oxygen-dissolved water is dropped and diffused into the water, and oxygen-rich water is evenly distributed throughout the enclosed water area, saving energy and oxygen to the entire enclosed water area, especially to the bottom layer. It is an object of the present invention to provide a method for purifying water in a closed water area, which can purify the water by supplying water.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention is to dispose a drainage passage between the deepest part of a closed water area of fresh water or seawater and a water surface, and to discharge the deepest water of the closed water area to a drainage passage. Through the surface of the water and forced into contact with oxygen in the atmosphere to take in oxygen. Hypoxic water in closed water areas is created by creating vertical convection in the entire closed water area and continuously moving and circulating the surface water, in which oxygen is dissolved, to the deepest part in contact with atmospheric oxygen. With oxygen-rich water to distribute oxygen-rich water throughout the enclosed water area and purify the water quality of the entire enclosed water area using oxygen. is there.
[0006]
The invention according to claim 2 is that the deepest part is provided by forming a concave portion in the bottom of the closed water area of freshwater or seawater, and the water bottom side of the closed water area is continuously deepened toward the deepest part to flow water. A drainage passage is provided between the deepest part of the closed water area of freshwater or seawater and the water surface, and the deepest water of the closed water area is forcibly discharged onto the water surface through the drainage passage. Contact with oxygen in the atmosphere to take in oxygen and use the phenomenon of falling water with a large specific gravity at the deepest part to generate vertical convection in the entire closed water body from the deepest part to the water surface and from the water surface to the deepest part. The oxygen-dissolved water in the enclosed water area is replaced by oxygen-rich water by continuously moving and circulating the surface water in which oxygen is dissolved in contact with the oxygen in the atmosphere toward the deepest part. To distribute oxygen-rich water evenly throughout the enclosed water area, Those composed of means to achieve the water purification of the entire closed water areas and use.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically based on embodiments of the invention illustrated in the drawings.
Here, FIG. 1 is a conceptual diagram of a method for purifying water in a closed water area, FIG. 2 is a side view of a drainage device, and FIG. 3 is a plan view of the drainage device.
[0008]
In the figure, a closed water body water purification apparatus 1 used for purifying fresh water or seawater in a closed water body a is provided with a drainage disposed between the deepest part 2 of the freshwater or seawater closed water body a and the water surface 3. A drainage hose 41 as a passage 4 and a drainage device 5 for forcibly discharging the water at the deepest part 2 of the closed water area a to the water surface 3 through the drainage passage 4 are provided.
[0009]
The deepest part 2 of the closed water area a is the deepest water bottom in the closed water area a, and when it exists in a natural state, that part is used. Further, the water bottom of the closed water area a is continuously deepened toward the deepest part 2, and has a flowing water-like topography such that water naturally flows along the water bottom and gathers at the deepest part 2. Is desired.
[0010]
If the deepest part 2 of the closed water area a cannot be specified in the natural state, the deepest part 2 is artificially provided by forming a deepest hole in the water bottom of the closed water area a than the surroundings. When the water bottom of the closed water area a is uneven in the natural state, the topography of the water bottom of the closed water area a is formed so as to be continuously deeper toward the deepest part 2 so that the water extends along the bottom surface. To form a flowing water-like terrain that flows naturally and gathers at the deepest part 2.
[0011]
The drainage hose 41 as the drainage passage 4 has a lower end disposed in the deepest part 2 of the closed water area a, so that water that has moved to the deepest part 2 can be taken in through the drainage hose 41. The upper end of the drain hose 41 is connected to a duct 51 of the drain device 5 provided on the water surface 3. A flexible hose is used as the drain hose 41, and has a structure in which a load is hardly applied in response to a change in the water level of the closed water area a.
[0012]
The drainage device 5 is a device for forcibly discharging the water that has moved to the deepest part 2 through the drainage hose 41 as the drainage passage 4 onto the water surface 3, and is attached to the duct 51 connected to the drainage hose 41 and the upper part of the duct 51. And a float 53 for floating the drainage device 5 on the water surface 3.
[0013]
The duct 51 is arranged vertically, the lower part of the duct 51 is formed in a cylindrical shape, the upper end of the drain hose 41 is connected to the lower end, and the axial flow pump 52 is arranged at the upper part. The duct 51 serves as an outlet for discharging the water sucked up through the drain hose 41 onto the water surface 3.
[0014]
The axial flow pump 52 forcibly pumps the water in the deepest part 2 through the drain hose 41, and rotates the propeller 52a that rotates to pump the water, the shaft 52b that is the rotating shaft of the propeller 52a, and the propeller 52a that rotates through the shaft 52b. It is comprised from the motor 52c which drives. The motor 52c is housed in a motor housing case 54.
[0015]
The propeller 52a is attached to a lower end of a vertically arranged shaft 52b, and an upper end of the shaft 52b having the lower end to which the propeller 52a is attached is interlocked with a motor 52c arranged above the shaft 52b.
[0016]
The floats 53 serve to float the drainage device 5 on the water surface 3, and four floats 53 are mounted on the outer peripheral side of the motor housing case 54 in this embodiment. The floats 53 are attached around the outer periphery of the motor housing case 54 at intervals so as not to hinder the discharge of the water at the deepest portion 2 from the upper end of the duct 51.
[0017]
Next, the operation based on the configuration of the embodiment of the present invention will be described below.
For example, on the water surface 3 above the deepest deepest part 2 of the closed water area a, in order to purify the water such as dirty fresh water or seawater of the closed water area a such as a dam, lake, lake, reservoir, reservoir, etc. The drainage device 5 of the closed water body water purification device 1 is towed, and the lower end of the drainage hose 41 as the drainage passage 4 connected to the lower end of the duct 51 of the drainage device 5 is lowered to the deepest part 2.
[0018]
The drainage device 5 on the water surface 3 is moored on the water surface 3 above the deepest portion 2 using a mooring rope or the like so that the drainage device 5 does not easily flow due to a water flow, wind, or the like. The lower end of the drain hose 41 is provided with a strainer for preventing dust from being sucked. This is made of metal so as to be heavy, and serves to prevent the drain hose 41 from moving.
[0019]
The water bottom of the closed water area a to which the method of purifying the water quality of the closed water area a according to the present invention is continuously deepened toward the deepest part 2, and the water naturally flows along the water bottom to form the deepest part. It is desirable that the terrain has a running water-like topography.
[0020]
When the natural deepest part 2 does not exist on the water bottom of the closed water area a or when the water bottom has severe irregularities, a concave hole is formed in the water bottom in advance by civil engineering work and the deepest part 2 is artificially formed. Or the topography of the water bottom of the closed water area a is formed so as to be continuously deeper toward the deepest part 2 so that the water naturally flows along the bottom surface and gathers at the deepest part 2 to form a flowing water-like topography. Form.
[0021]
As described above, after the drainage hose 41 and the drainage device 5 as the drainage passage 4 of the closed water body water purification device 1 are installed in the freshwater or seawater closed water region a, the axial pump 52 of the drainage device 5 is operated. Let it. When the motor 52c of the axial flow pump 52 operates, the propeller 52a attached to the lower end of the shaft 52b linked to the motor 52c rotates in a certain direction, that is, in a direction to pump water.
[0022]
When the propeller 52a of the axial pump 52 rotates, an upward flow is generated in the duct 51 and the inside of the drainage hose 41 as the drainage passage 4, and the deepest portion 2 at the lower end of the lower end of the drainage hose 41 is in an oxygen-deficient state. The water is sucked into the drain hose 41 and rises inside, and is discharged onto the water surface 3 from the upper end of the duct 51 to which the upper end of the drain hose 41 is connected.
[0023]
The oxygen-depleted water in the deepest part 2 comes into contact with the oxygen in the air when discharged onto the water surface 3, and the oxygen in the air dissolves in the water in the oxygen-depleted state and contains abundant oxygen. Become water. At this time, the water having a low water temperature in the deepest part 2 is heated on the water surface 3 by sunlight or the like, and the water temperature rises slightly.
[0024]
In the deepest part 2 of the closed water area a, since water is continuously discharged onto the water surface 3, the surrounding water moves toward the deepest part 2. For this reason. Convection occurs in the vertical direction between the water surface 3 and the deepest part 2 of the closed water area a. That is, an upward flow occurs through the deepest portion 2 and the drainage hose 41 and the duct 51 as the drainage passage 4, and a downward flow from the entire water surface 3 toward the deepest portion 2 occurs around the drainage passage 4.
[0025]
The water moving from the entire water surface 3 toward the deepest part 2 on the lower side along the descending flow contains abundant oxygen, so that the water in the entire closed water area a becomes the surface of the water surface 3 with time. It is gradually replaced by oxygen-rich water from the whole down.
[0026]
Similarly, since the water containing oxygen is warmed by sunlight and has a high water temperature, the water in the entire closed water area a gradually increases in temperature from the entire surface of the water surface 3 to the lower side with time. It is replaced by water.
[0027]
In this way, the oxygen-depleted water in the closed water area a is replaced with oxygen-rich water, and the oxygen-rich water can be distributed evenly throughout the closed water area a. This makes it possible to purify the water quality of the entire closed water area a using oxygen.
[0028]
[Experimental example]
The experiment was performed at Amagase Dam in Taku City, Saga Prefecture shown in FIG. 4 as closed water area a. Figures 5 to 8 show dissolved oxygen, water temperature, total phosphorus, COD (chemical oxygen demand) in July and September of last year (2001) before installation of the device and in July and September of this year after installation of the device (2002). Volume).
FIG. 5 shows that the anoxic state below the middle layer that existed last year has completely disappeared. FIG. 6 shows that the water temperature is almost uniform from the lower layer to the upper layer. FIG. 7 also shows that the dissolution of phosphorus from the mud at the bottom of the water is suppressed with the elimination of the anoxic state, and that the total phosphorus in the water is lower than last year. FIG. 8 shows that the value of COD has been improved.
[0029]
It should be noted that the present invention is not limited to the above-described embodiment of the present invention, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.
[0030]
【The invention's effect】
As is apparent from the above description, according to the water purification method for closed water bodies according to the first and second aspects of the present invention, cold and large specific gravity water is diffused in a horizontal direction from a high place to a low place. Utilizing the phenomenon of falling and low-oxygen water's ability to efficiently absorb oxygen on the surface of water, the deepest water, which is cold and low in oxygen, is forcibly discharged onto the surface of water, and oxygen in the atmosphere is Water, oxygen-dissolved water is dropped and diffused into the water, and oxygen-rich water is evenly distributed throughout the enclosed water area.By supplying energy to the enclosed water area, especially the bottom layer, Water purification can be achieved. In addition, in order to achieve this, a very simple structure consisting only of a drainage passage arranged between the deepest part and the water surface and a drainage device for forcibly discharging the deepest water to the water surface through the drainage passage, and Also, the running cost can be realized at a very low cost.
In addition, in addition to the above effects, the water temperature of the entire closed water area can be made substantially uniform, and particularly, the water temperature of the low water temperature portion of the bottom layer can be increased, and thus a very novel and beneficial effect is achieved. is there.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a method for purifying water in a closed water area showing an embodiment of the present invention.
FIG. 2 is a side view of the drainage device showing the embodiment of the present invention.
FIG. 3 is a plan view of the drainage device showing the embodiment of the present invention.
FIG. 4 is a plan view of an experimental place.
FIG. 5 is a diagram showing results before and after an experiment for improving the amount of dissolved oxygen.
FIG. 6 is a diagram showing results before and after an experiment of water temperature improvement.
FIG. 7 is a diagram showing the results before and after the experiment for the improvement of total phosphorus.
FIG. 8 is a diagram showing results before and after an experiment of COD (chemical oxygen demand) improvement.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Closed water area water purification apparatus 2 Deepest part 3 Water surface 4 Drainage passage 41 Drain hose 5 Drainage device 51 Duct 52 Axial pump 52a Propeller 52b Shaft 52c Motor 53 Float 54 Motor accommodation case a Closed water area
