JP2002088732A - Bottom quality improving method - Google Patents
Bottom quality improving methodInfo
- Publication number
- JP2002088732A JP2002088732A JP2000286444A JP2000286444A JP2002088732A JP 2002088732 A JP2002088732 A JP 2002088732A JP 2000286444 A JP2000286444 A JP 2000286444A JP 2000286444 A JP2000286444 A JP 2000286444A JP 2002088732 A JP2002088732 A JP 2002088732A
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- Prior art keywords
- sediment
- surface layer
- floated
- nitrogen
- stirred
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、海、湖沼、河川等
の水底に堆積した底質の性状を改質する底質の改質方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the quality of sediment deposited on the bottom of a sea, lake, marsh, river or the like.
【０００２】[0002]
【従来の技術】海、湖沼、河川等の水域、特に閉鎖性水
域においては、水質の富栄養化による水質汚濁が問題と
なっている。すなわち、リンや窒素といった栄養塩類の
濃度が増加して水質が富栄養化すると、表層で大量発生
した植物プランクトンが死骸となって水底に沈降し、該
水底では、かかる死骸の有機物分解で多量の酸素が消費
され嫌気性の環境となって貧酸素化する。2. Description of the Related Art Water pollution due to eutrophication of water quality has become a problem in waters such as the sea, lakes and rivers, particularly in closed waters. That is, when the concentration of nutrients such as phosphorus and nitrogen increases and the water quality becomes eutrophic, phytoplankton generated in large quantities in the surface layer becomes dead bodies and sinks to the bottom of the water. Oxygen is consumed, resulting in an anaerobic environment and anoxia.
【０００３】また、かかる底層での貧酸素化は、アンモ
ニアや硫化水素などが底質や水中の有機物から溶出し、
貧酸素化と相まって多くの水生生物が死滅する原因とな
るとともに、栄養塩類の溶出によって水質の富栄養化が
さらに進行するといった悪循環をもたらす。また、表層
での藻類の異常発生は、水道の浄化処理場で濾過装置を
目詰まりさせたり、水道水を緑色に染めたり、かび臭を
付けたりといった弊害を招く原因となる。[0003] In addition, the oxygen depletion in the bottom layer is caused by the fact that ammonia, hydrogen sulfide, etc. are eluted from sediment or organic matter in water,
Along with the anoxia, it causes many aquatic organisms to die, and the elution of nutrients leads to a vicious cycle in which the eutrophication of water quality further progresses. In addition, abnormal occurrence of algae on the surface layer may cause adverse effects such as clogging of a filtration device in a water purification treatment plant, dyeing of tap water in green, and adding a musty odor.
【０００４】[0004]
【発明が解決しようとする課題】かかる水質汚濁を改善
するため、例えば、流入負荷の低減、底質の浚渫、藻類
除去、底質被覆、湖水循環等の方法が試みられている
が、底質を浚渫する場合には、浚渫された土を産業廃棄
物として処理しなければならないという問題を生じてい
た。In order to improve such water pollution, for example, methods such as reduction of inflow load, dredging of sediment, removal of algae, sediment coating and lake water circulation have been tried. In the case of dredging, there is a problem that the dredged soil must be treated as industrial waste.
【０００５】また、底質に覆砂を施す方法も試みられて
いるが、底質を被覆したとはいえその内部から少しずつ
有機物が溶出して酸素を消費するのを避けられず、底層
での貧酸素化を長期間防止することは困難であるという
問題も生じていた。[0005] Further, a method of applying sand to the sediment has also been attempted. However, although the sediment is covered, it is unavoidable that organic substances elute from the inside little by little and oxygen is consumed, so that the bottom layer is not covered. There is also a problem that it is difficult to prevent oxygen depletion of oxygen for a long time.
【０００６】本発明は、上述した事情を考慮してなされ
たもので、底質からの栄養塩類の溶出や硫化水素等の有
害物質の生成を防止するとともに底層における貧酸素化
を防止することが可能な底質の改質方法を提供すること
を目的とする。The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to prevent elution of nutrients from sediment and generation of harmful substances such as hydrogen sulfide, and to prevent hypoxia in the bottom layer. It is an object of the present invention to provide a possible method of modifying bottom sediment.
【０００７】[0007]
【課題を解決するための手段】上記目的を達成するた
め、本発明に係る底質の改質方法は請求項１に記載した
ように、海、湖沼、河川等の水底に堆積した底質を表層
付近まで攪拌浮上させた後、沈降した底質を再び表層付
近まで攪拌浮上させるものである。In order to achieve the above-mentioned object, a method for modifying sediment according to the present invention is characterized in that, as set forth in claim 1, the sediment deposited on the bottom of the sea, lake, marsh, river, etc. After stirring and floating near the surface layer, sedimented sediment is again stirred and floated near the surface layer.
【０００８】また、本発明に係る底質の改質方法は、前
記底質の攪拌浮上を繰り返し行うものである。[0008] Further, in the method of reforming bottom sediment according to the present invention, the above-mentioned bottom sediment is repeatedly stirred and floated.
【０００９】また、本発明に係る底質の改質方法は、前
記攪拌浮上を夜間に行うものである。Further, in the method of reforming sediment according to the present invention, the stirring and floating is performed at night.
【００１０】また、本発明に係る底質の改質方法は請求
項４に記載したように、海、湖沼、河川等の水底に堆積
した底質を昼間に表層近傍まで攪拌浮上させ、沈降した
底質を再び夜間に表層付近まで攪拌浮上させるものであ
る。Further, in the method for modifying sediment according to the present invention, the sediment deposited on the bottom of the sea, lake, marsh, river or the like is stirred and floated to near the surface layer in the daytime and settled. The sediment is stirred and floated to the vicinity of the surface layer again at night.
【００１１】請求項１に係る底質の改質方法において
は、まず、海、湖沼、河川等の水底に堆積した底質を表
層付近まで攪拌浮上させる。攪拌浮上させるには、例え
ばグラブ船から吊持したグラブを水中に吊り降ろし、該
グラブで底質をつかみ、かかる状態で表層付近まで揚泥
した後、適当な高さでグラブを開く方法や、水中ポンプ
を使って水を底質に噴射しその勢いで底質を表層にまき
あげる方法、あるいはスラリーポンプでいったん底質を
浚渫しこれを表層に再投入する方法などが考えられる。In the method for modifying the sediment according to the first aspect, first, the sediment deposited on the water bottom of the sea, lake, marsh, river or the like is stirred and floated to the vicinity of the surface layer. In order to agitate and float, for example, a grab suspended from a grab ship is suspended in water, the sediment is grasped by the grab, mud is pumped to near the surface in this state, and a method of opening the grab at an appropriate height, A method of injecting water into the sediment using a submersible pump and raising the sediment to the surface with the force, or a method of dredging the sediment once with a slurry pump and re-injecting it into the surface can be considered.
【００１２】このようにすると、底質中に含まれていた
アンモニア態窒素（ＮＨ4―Ｎ）は、表層付近に含まれ
ている酸素によって硝化され、硝酸態窒素へと変化する
（ＮＯ3―Ｎ）。ちなみに、この反応には好気性細菌で
ある硝化菌が関与する。また、底質中に含まれていた硫
化水素は、やはり表層付近に含まれている酸素で酸化さ
れて硫黄、さらには硫酸イオンへと変化する。In this manner, the ammonia nitrogen (NH 4 —N) contained in the sediment is nitrified by the oxygen contained near the surface layer and changes to nitrate nitrogen (NO 3 —). N). Incidentally, nitrifying bacteria, which are aerobic bacteria, are involved in this reaction. Further, the hydrogen sulfide contained in the sediment is oxidized by oxygen contained also in the vicinity of the surface layer, and changes to sulfur and further to sulfate ions.
【００１３】かかる反応が進行している間、攪拌作業は
中断して静置する。そのため、いったん攪拌浮上した底
質はやがて沈降するが、次に、このように沈降した底質
を、上述したと同様にして再び表層付近まで攪拌浮上さ
せる。[0013] While the reaction is in progress, the stirring operation is interrupted and allowed to stand. For this reason, the sediment that has once floated with stirring is settled down, and then the sediment that has settled in this way is stirred and floated again near the surface layer in the same manner as described above.
【００１４】このようにすると、表層付近においては、
先の反応、すなわちアンモニア態窒素の硝化及び硫化水
素の酸化、さらには微生物等による呼吸によって貧酸素
化しているため、今度は、嫌気性細菌である脱窒菌が硝
酸態窒素に作用して窒素ガスに変化させ、該窒素ガス
は、大気中へと放出される。In this manner, in the vicinity of the surface layer,
Since the previous reaction, that is, nitrification of ammonia nitrogen and oxidation of hydrogen sulfide, and anoxia due to respiration by microorganisms and the like, denitrifying bacteria, which are anaerobic bacteria, act on nitrate nitrogen to produce nitrogen gas. And the nitrogen gas is released into the atmosphere.
【００１５】なお、一回目の攪拌浮上による酸素消費で
も表層付近が貧酸素化しなかった場合には、底質の攪拌
浮上を繰り返し行い、アンモニア態窒素の硝化及び硫化
水素の酸化による表層での酸素消費を促すようにすれば
よい。If oxygen is not depleted in the vicinity of the surface layer even after the first consumption of oxygen by stirring and floating, the stirring and floating of the sediment is repeated, and nitrification of ammonia nitrogen and oxidation of hydrogen sulfide on the surface by oxygen oxidation. What is necessary is just to encourage consumption.
【００１６】このようにすれば、いずれは表層が貧酸素
化して嫌気性細菌である脱窒菌が活性化し、硝酸態窒素
は必然的に窒素ガスとなって大気中に放出される。[0016] In this way, the surface layer will eventually become deoxygenated and the denitrifying bacteria which are anaerobic bacteria will be activated, and nitrate nitrogen will inevitably be released into the atmosphere as nitrogen gas.
【００１７】ここで、海や湖沼の表層近傍に一定量以上
の植物プランクトンが生息している場合、上述した攪拌
浮上作業を昼間だけに限定して行うと、植物プランクト
ンの光合成による酸素供給によって、いつまで経っても
表層が貧酸素化しないといった事態も懸念される。Here, when a certain amount or more of phytoplankton inhabits near the surface of the sea or lake, if the above-mentioned stirring and floating work is performed only during the daytime, oxygen supply by phytoplankton photosynthesis causes There is a concern that the surface layer will not be deoxygenated forever.
【００１８】そこで上述した攪拌浮上作業を夜間に限定
して行うようにすれば、植物プランクトンの光合成によ
る酸素供給が停止しているため、底質の攪拌浮上を行う
ことによって表層を確実に貧酸素化させることが可能と
なる。Therefore, if the above-mentioned stir flotation operation is performed only during the night, oxygen supply by photosynthesis of phytoplankton is stopped. It becomes possible to make it.
【００１９】請求項４に係る底質の改質方法において
は、まず、海、湖沼、河川等の水底に堆積した底質を昼
間に表層付近まで攪拌浮上させる。In the method for modifying sediment according to a fourth aspect, first, the sediment deposited on the bottom of the sea, lake, marsh, river or the like is stirred and floated to the vicinity of the surface layer in the daytime.
【００２０】このようにすると、請求項１に係る発明と
同様、底質中に含まれていたアンモニア態窒素（ＮＨ4
―Ｎ）は、表層付近に含まれている酸素によって硝化さ
れ、硝酸態窒素へと変化するとともに（ＮＯ3―Ｎ）、
底質中に含まれていた硫化水素についても酸化されて硫
黄、硫酸イオン等となるが、攪拌浮上を行う時間帯が昼
間であるため、アンモニア態窒素及び硫化水素は、植物
プランクトンによって多量に供給される酸素により、そ
の硝化及び酸化が促進され、硝酸態窒素及び硫黄等への
化学反応は短時間に終了する。In this manner, similarly to the invention according to the first aspect, the ammonia nitrogen (NH 4) contained in the sediment is
-N) is nitrified by oxygen contained near the surface layer and changes to nitrate nitrogen (NO 3 -N),
Hydrogen sulfide contained in the sediment is also oxidized to sulfur, sulfate ions, etc., but since the time of stirring and flotation is in the daytime, ammonia nitrogen and hydrogen sulfide are supplied in large amounts by phytoplankton Oxygen promotes nitrification and oxidation, and the chemical reaction to nitrate nitrogen, sulfur and the like is completed in a short time.
【００２１】かかる反応が進行している間、攪拌作業は
中断して静置する。そのため、いったん攪拌浮上した底
質はやがて沈降するが、次に、このように沈降した底質
を、今度は夜間に再び表層付近まで攪拌浮上させる。While such a reaction is in progress, the stirring operation is interrupted and allowed to stand. For this reason, the sediment that once stirs and floats eventually settles, and then the sediment that has settled in this way is stirred and floated again near the surface layer at night this time.
【００２２】このようにすると、植物プランクトンによ
る光合成が停止しているため、表層付近は、水面からの
溶け込みを除き、大量の酸素供給は絶たれた状態とな
る。そのため、一回目の攪拌浮上による硝化及び酸化に
よって貧酸素化した場合はもちろん、表層にまだ酸素が
残っている場合であっても、二回目の攪拌浮上による硝
化及び酸化によって表層は貧酸素化する。そして、貧酸
素化した結果、今度は、嫌気性細菌である脱窒菌が硝酸
態窒素に作用して窒素ガスに変化させ、該窒素ガスは、
大気中へと放出される。In this case, since photosynthesis by phytoplankton is stopped, a large amount of oxygen is cut off near the surface except for dissolution from the water surface. Therefore, the surface layer is deoxygenated by nitrification and oxidation by the second stirring flotation, even when oxygen is still left on the surface layer, not to mention the case where oxygen is still left on the surface layer, as well as when nitrification and oxidation by the first stirring flotation occur. . Then, as a result of the anoxia, the denitrifying bacterium, which is an anaerobic bacterium, acts on nitrate nitrogen to change it into nitrogen gas.
Released into the atmosphere.
【００２３】上述した各発明においては、攪拌浮上作業
による水質汚濁や表層貧酸素化によって海洋生物の死滅
を招くおそれがあるが、海、湖沼、河川等の水底から水
面まで延びる不透水性材料を壁状に配置して閉鎖水域を
形成し、該閉鎖水域内で前記攪拌浮上作業を行うように
したならば、水質汚濁や表層貧酸素化が生じる水域が限
定されるため、海洋や湖沼環境の生態系に影響を与える
おそれがなくなる。In each of the above-mentioned inventions, there is a possibility that marine organisms may be killed due to water pollution or surface deoxygenation due to agitation floating work. However, an impermeable material extending from the bottom of the sea, lake, marsh or river to the water surface may be used. If the stir flotation work is performed in the closed water area by arranging it in a wall shape and forming the closed water area, the water area where water pollution and surface hypoxia occur is limited, so that the marine and lake environment There is no risk of affecting the ecosystem.
【００２４】不透水性材料は、基本的にはどのような材
料で構成してもかまわないが、例えば重りを付けた可搬
性プラスチック板を四角に囲んで閉鎖水域を構成するよ
うにすれば、かかるプラスチック板で囲まれる閉鎖水域
を順次移動していくことによって、一定面積の水域を海
洋等の生態系に悪影響を及ぼすことなく、底質を確実に
改質することが可能となる。The water-impermeable material may be basically made of any material. For example, if a closed plastic area is constructed by surrounding a weighted portable plastic plate with a square, By sequentially moving in a closed water area surrounded by such a plastic plate, it becomes possible to surely reform the sediment of the water area of a certain area without adversely affecting ecosystems such as the ocean.
【００２５】なお、本発明は、主として海、湖沼といっ
た現場水域にて底質の改質を行うことを想定している
が、本発明でいうところの水底とは、必ずしも現場水域
の水域を意味するものではなく、処理槽の底部もここに
含まれる。In the present invention, it is assumed that the sediment is reformed mainly in the site waters such as the sea and lakes. However, the term “water bottom” as used in the present invention does not necessarily mean the water in the site waters. Instead, the bottom of the processing tank is also included here.
【００２６】すなわち、現場水域の底質をとりあえず浚
渫し、かかる浚渫土を例えば湾岸に設置された処理槽内
に投入し、しかる後、該処理槽の底部、すなわち水底に
沈降堆積した底質である浚渫土に対し、上述した各発明
を適用することが可能である。That is, the sediment of the on-site water area is dredged for the time being, and the dredged soil is put into a treatment tank installed on, for example, a bay shore. Thereafter, the sediment is deposited on the bottom of the treatment tank, ie, the sediment deposited on the water bottom. Each of the above-described inventions can be applied to a certain dredged soil.
【００２７】[0027]
【発明の実施の形態】以下、本発明に係る底質の改質方
法の実施の形態について、添付図面を参照して説明す
る。なお、従来技術と実質的に同一の部品等については
同一の符号を付してその説明を省略する。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a method for reforming sediment according to the present invention will be described with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.
【００２８】（第１実施形態）(First Embodiment)
【００２９】図１は、本実施形態に係る底質の改質方法
を示した作業手順図である。同図でわかるように、本実
施形態に係る底質の改質方法を用いて底質の改質を行う
には、まず、同図(a)に示すように、水底である海底１
に堆積した底質２を表層３付近まで攪拌浮上させる。FIG. 1 is an operation procedure diagram showing a method for reforming sediment according to the present embodiment. As can be seen from the figure, in order to reform the sediment using the method for reforming the sediment according to the present embodiment, first, as shown in FIG.
The sediment 2 deposited on the surface is stirred and floated to the vicinity of the surface layer 3.
【００３０】底質２を攪拌浮上させるには、同図に示す
ようにグラブ船４から吊持したグラブ５を海中に吊り降
ろし、該グラブで底質２をつかみ、かかる状態で同図
(b)に示すように表層３付近まで揚泥した後、適当な高
さでグラブ５を開けばよい。In order to stir and float the sediment 2, the glove 5 suspended from the grab boat 4 is suspended in the sea as shown in the figure, and the sediment 2 is grasped by the grab.
After lifting the mud to the vicinity of the surface layer 3 as shown in (b), the glove 5 may be opened at an appropriate height.
【００３１】このようにすると、底質２中に含まれてい
たアンモニア態窒素（ＮＨ4―Ｎ）は、表層３付近に含
まれている酸素によって硝化され、硝酸態窒素へと変化
する（ＮＯ3―Ｎ）。ちなみに、この反応には好気性細
菌である硝化菌が関与する。また、底質２中に含まれて
いた硫化水素は、やはり表層３付近に含まれている酸素
で酸化されて硫黄となる。In this manner, the ammonia nitrogen (NH 4 —N) contained in the sediment 2 is nitrified by the oxygen contained in the vicinity of the surface layer 3 and changes to nitrate nitrogen (NO). 3 -N). Incidentally, nitrifying bacteria, which are aerobic bacteria, are involved in this reaction. Further, the hydrogen sulfide contained in the sediment 2 is oxidized by oxygen contained also in the vicinity of the surface layer 3 to become sulfur.
【００３２】かかる反応が進行している間、攪拌作業は
中断して静置する。そのため、いったん攪拌浮上した底
質２はやがて沈降するが、次に、このように沈降した底
質２を、同図(c)に示すように上述したと同様にして再
び表層３付近まで攪拌浮上させる。While such a reaction is in progress, the stirring operation is interrupted and allowed to stand. As a result, the sediment 2 that has once floated with stirring is settled down, and then the sediment 2 that has settled in this way is stirred and floated again near the surface layer 3 in the same manner as described above, as shown in FIG. Let it.
【００３３】このようにすると、表層３付近において
は、先の反応、すなわちアンモニア態窒素の硝化及び硫
化水素の酸化によって貧酸素化しているため、今度は、
嫌気性細菌である脱窒菌が硝酸態窒素に作用して窒素ガ
スＮ2に変化させ、該窒素ガスは大気中へと放出され
る。In this manner, near the surface layer 3, the oxygen is deoxygenated by the previous reaction, that is, nitrification of ammonia nitrogen and oxidation of hydrogen sulfide.
Denitrifying bacteria, which are anaerobic bacteria varied nitrogen gas N 2 to act on nitrate, nitrogen gas is released into the atmosphere.
【００３４】以上説明したように、本実施形態に係る底
質の改質方法によれば、アンモニア態窒素の形で底質に
含まれている窒素を攪拌浮上させて表層付近で硝化する
ことにより、いったん硝酸態窒素へと変化させ、次い
で、該硝酸態窒素の形で沈降した底質を貧酸素化してい
る表層に再び攪拌浮上させることによって今度は脱窒菌
の作用で窒素ガスへと変化させるようにしたので、底質
に含まれる窒素を窒素ガスの形で確実に大気に放出させ
ることができる。また、底質内に含まれる硫化水素につ
いても、表層での酸化によって硫黄に変化し、本来の形
で海に戻すことが可能となる。As described above, according to the method of reforming the sediment according to the present embodiment, nitrogen contained in the sediment in the form of ammonia nitrogen is stirred and floated to be nitrified near the surface layer. Once, it is changed to nitrate nitrogen, and then the sediment sedimented in the form of nitrate nitrogen is again stirred and floated on the surface of oxygen-deficient surface, which is then changed to nitrogen gas by the action of denitrifying bacteria. As a result, nitrogen contained in the sediment can be reliably released to the atmosphere in the form of nitrogen gas. Hydrogen sulfide contained in sediment also changes to sulfur by oxidation at the surface layer, and can be returned to the sea in its original form.
【００３５】したがって、底質内に含まれる有機物の含
有量を低下させることが可能となり、その結果として、
底層における貧酸素化、それに伴う水生生物の死滅を防
止することが可能となる。ちなみに、底層が好気性に変
化することによって、底質内のリンも水中の鉄やカルシ
ウムと共沈して安定化し、その点でも底質の改質を図る
ことができる。Therefore, it is possible to reduce the content of organic matter contained in the sediment, and as a result,
It becomes possible to prevent hypoxia in the bottom layer and the death of aquatic organisms associated therewith. By the way, when the bottom layer changes to aerobic, phosphorus in the sediment is also co-precipitated with iron and calcium in the water, and is stabilized. In that respect, it is possible to improve the sediment.
【００３６】また、本実施形態に係る底質の改質方法に
よれば、底質内の有機物含有量を原位置のまま低下させ
るものであるため、従来の覆砂工法のように良質砂を必
要としないことはもちろん、底質内の有機物が良質砂を
介して一定時間経過後に溶出したり、従来の浚渫工法の
ように浚渫された土の処理に困るといった事態も生じな
い。Further, according to the method for modifying the sediment according to the present embodiment, the organic matter content in the sediment is reduced in situ, so that good-quality sand is removed as in the conventional sand covering method. Needless to say, the organic matter in the sediment does not elute through the high-quality sand after a certain period of time, and there is no problem that the dredged soil is troubled as in the conventional dredging method.
【００３７】本実施形態では特に言及しなかったが、一
回目の攪拌浮上による酸素消費でも表層３付近が貧酸素
化しなかった場合には、底質２の攪拌浮上を繰り返し行
い、アンモニア態窒素の硝化及び硫化水素の酸化による
表層３での酸素消費を促すようにすればよい。Although not specifically mentioned in the present embodiment, when oxygen is not deoxidized in the vicinity of the surface layer 3 even by the first consumption of oxygen by stirring and floating, the stirring and floating of the sediment 2 is repeated to remove ammonia nitrogen. What is necessary is just to promote oxygen consumption in the surface layer 3 by nitrification and oxidation of hydrogen sulfide.
【００３８】このようにすれば、いずれは表層３が貧酸
素化して嫌気性細菌である脱窒菌が活性化し、硝酸態窒
素を必然的に窒素ガスとして大気中に放出することが可
能となる。In this way, the surface layer 3 will eventually become deoxygenated and the anaerobic bacteria denitrifying bacteria will be activated, and it will be possible to inevitably release nitrate nitrogen into the atmosphere as nitrogen gas.
【００３９】また、本実施形態では、植物プランクトン
の存在を無視したが、海や湖沼の表層近傍に一定量以上
の植物プランクトンが生息している場合、上述した攪拌
浮上作業を昼間だけに限定して行うと、植物プランクト
ンの光合成による酸素供給によって、いつまで経っても
表層が貧酸素化しないといった事態も懸念される。In this embodiment, the existence of phytoplankton is neglected. However, when a certain amount or more of phytoplankton inhabits near the surface of the sea or lake, the above-described stirring and floating operation is limited to daytime only. In such a case, there is a concern that the surface layer will not be deoxygenated forever due to oxygen supply by phytoplankton photosynthesis.
【００４０】かかる場合においては、上述した攪拌浮上
作業を夜間に限定して行えばよい。このようにすれば、
植物プランクトンの光合成による酸素供給が停止してい
るため、底質２の攪拌浮上を行うことによって表層３を
確実に貧酸素化させることが可能となる。In such a case, the above-described stirring and floating operation may be performed only at night. If you do this,
Since the supply of oxygen by phytoplankton photosynthesis is stopped, the surface layer 3 can be reliably deoxygenated by stirring and floating the sediment 2.
【００４１】また、上述した実施形態においては、攪拌
浮上作業による水質汚濁や表層貧酸素化によって海洋生
物の死滅を招くおそれがある。Further, in the above-mentioned embodiment, there is a possibility that marine organisms may be killed due to water pollution or surface hypoxia caused by the stirring and floating operation.
【００４２】そこで、図２に示すように、重り１１を付
けた４枚の可搬性プラスチック板１２をボックス状に底
質２の上に立設して閉鎖水域１３を構成するようにすれ
ば、かかるプラスチック板１２で囲まれる閉鎖水域１３
を例えば同図(b)の平面図に示すように順次移動してい
くことによって、一定面積の水域を海洋等の生態系に悪
影響を及ぼすことなく、底質２を確実に改質することが
可能となる。Therefore, as shown in FIG. 2, four portable plastic plates 12 with weights 11 are erected on the sediment 2 in a box shape to constitute a closed water area 13. Closed water area 13 surrounded by such a plastic plate 12
For example, as shown in the plan view of FIG. 2 (b), it is possible to surely reform the sediment 2 without adversely affecting a certain area of the water body to the ecosystem such as the ocean. It becomes possible.
【００４３】（第２実施形態）(Second Embodiment)
【００４４】次に、第２実施形態について説明する。な
お、第１実施形態と実質的に同一の部品等については同
一の符号を付してその説明を省略する。Next, a second embodiment will be described. Note that components that are substantially the same as those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.
【００４５】図３は、本実施形態に係る底質の改質方法
を示した作業手順図である。同図でわかるように、本実
施形態に係る底質の改質方法を用いて底質の改質を行う
には、まず、同図(a)に示すように、水底である海底１
に堆積した底質２を表層３付近まで攪拌浮上させる。FIG. 3 is a work procedure diagram showing a method for reforming sediment according to the present embodiment. As can be seen from the figure, in order to reform the sediment using the method for reforming the sediment according to the present embodiment, first, as shown in FIG.
The sediment 2 deposited on the surface is stirred and floated to the vicinity of the surface layer 3.
【００４６】底質２を攪拌浮上させるには、第１実施形
態と同様、同図に示すようにグラブ船４から吊持したグ
ラブ５を海中に吊り降ろし、該グラブで底質２をつか
み、かかる状態で同図(b)に示すように表層３付近まで
揚泥した後、適当な高さでグラブ５を開くようにすれば
よいが、かかる攪拌浮上作業は、植物プランクトンが光
合成を活発に行っている昼間に行う。In order to stir and float the sediment 2, as in the first embodiment, the glove 5 suspended from the glove ship 4 is suspended in the sea as shown in FIG. In this state, as shown in FIG. 3 (b), the grab 5 may be opened at an appropriate height after the mud is raised up to the vicinity of the surface layer 3, but the stir-floating operation is performed by phytoplankton that actively activates photosynthesis. Do it in the daytime you go.
【００４７】このようにすると、底質２中に含まれてい
たアンモニア態窒素（ＮＨ4―Ｎ）は、第１実施形態と
同様、表層３付近に含まれている酸素によって硝化さ
れ、硝酸態窒素へと変化するとともに（ＮＯ3―Ｎ）、
底質２中に含まれていた硫化水素についても酸化されて
硫黄となるが、攪拌浮上を行う時間帯が昼間であるた
め、アンモニア態窒素及び硫化水素は、植物プランクト
ンによって多量に供給される酸素によってその硝化及び
酸化が促進され、硝酸態窒素及び硫黄への化学反応は短
時間に終了する。In this manner, the ammonia nitrogen (NH 4 —N) contained in the sediment 2 is nitrified by the oxygen contained in the vicinity of the surface layer 3 as in the first embodiment, and becomes nitrate. With the change to nitrogen (NO 3 -N),
Hydrogen sulfide contained in the sediment 2 is also oxidized to sulfur, but since the time for stirring and flotation is during the daytime, ammonia nitrogen and hydrogen sulfide are supplied in large amounts by oxygen supplied by phytoplankton. Promotes nitrification and oxidation, and the chemical reaction to nitrate nitrogen and sulfur is completed in a short time.
【００４８】かかる反応が進行している間、攪拌作業は
中断して静置する。そのため、いったん攪拌浮上した底
質２はやがて沈降するが、次に、このように沈降した底
質２を、今度は同図(c)に示すように夜間に再び表層３
付近まで攪拌浮上させる。While such a reaction is in progress, the stirring operation is interrupted and allowed to stand. As a result, the sediment 2 that has once floated under agitation settles down, and then the sediment 2 that has settled in this way is again transferred to the surface layer 3 at night, as shown in FIG.
Stir and float to near.
【００４９】このようにすると、植物プランクトンによ
る光合成が停止しているため、表層３付近は、水面から
の溶け込みを除き、大量の酸素供給は絶たれた状態とな
る。そのため、一回目の攪拌浮上による硝化及び酸化に
よって貧酸素化した場合はもちろん、表層３にまだ酸素
が残っている場合であっても、二回目の攪拌浮上による
硝化及び酸化によって表層は貧酸素化する。そして、貧
酸素化した結果、今度は、嫌気性細菌である脱窒菌が硝
酸態窒素に作用して窒素ガスＮ2に変化させ、該窒素ガ
スは大気中へと放出される。なお、表層が貧酸素化する
まで、夜間における攪拌浮上作業が複数回に及ぶ場合も
考えられる。In this case, since photosynthesis by phytoplankton is stopped, a large amount of oxygen is supplied near the surface layer 3 except for dissolution from the water surface. Therefore, the surface layer is deoxygenated by the nitrification and oxidation by the second stirring and floating, not only when the oxygen is still left in the surface layer 3, but also when the oxygen is still left in the surface layer 3 as well as when the oxygen is left in the nitrification and oxidation by the first stirring and floating. I do. Then, as a result of the anoxia, the denitrifying bacterium, which is an anaerobic bacterium, acts on nitrate nitrogen to change it into nitrogen gas N 2 , and the nitrogen gas is released into the atmosphere. It should be noted that the stirring and floating operation at night may be performed a plurality of times until the surface layer becomes deoxygenated.
【００５０】以上説明したように、本実施形態に係る底
質の改質方法によれば、アンモニア態窒素の形で底質に
含まれている窒素を攪拌浮上させて表層付近で硝化する
ことにより、いったん硝酸態窒素へと変化させ、次い
で、該硝酸態窒素の形で沈降した底質を貧酸素化してい
る表層に再び攪拌浮上させることによって今度は脱窒菌
の作用で窒素ガスへと変化させるようにしたので、底質
に含まれる窒素を窒素ガスの形で確実に大気に放出させ
ることができる。また、底質内に含まれる硫化水素につ
いても、表層での酸化によって硫黄に変化し、本来の形
で海に戻すことが可能となる。As described above, according to the method for modifying sediment according to the present embodiment, nitrogen contained in sediment in the form of ammonia nitrogen is stirred and floated to be nitrified near the surface layer. Once, it is changed to nitrate nitrogen, and then the sediment sedimented in the form of nitrate nitrogen is again stirred and floated on the deoxygenated surface layer, this time being changed to nitrogen gas by the action of denitrifying bacteria. As a result, nitrogen contained in the sediment can be reliably released to the atmosphere in the form of nitrogen gas. Hydrogen sulfide contained in sediment also changes to sulfur by oxidation at the surface layer, and can be returned to the sea in its original form.
【００５１】したがって、底質内に含まれる有機物の含
有量を低下させることが可能となり、その結果として、
底層における貧酸素化、それに伴う水生生物の死滅を防
止することが可能となる。ちなみに、底層が好気性に変
化することによって、底質内のリンも水中の鉄やカルシ
ウムと共沈して安定化し、その点でも底質の改質を図る
ことができる。Therefore, it is possible to reduce the content of the organic matter contained in the sediment, and as a result,
It becomes possible to prevent hypoxia in the bottom layer and the death of aquatic organisms associated therewith. By the way, when the bottom layer changes to aerobic, phosphorus in the sediment is also co-precipitated with iron and calcium in the water, and is stabilized. In that respect, it is possible to improve the sediment.
【００５２】また、本実施形態に係る底質の改質方法に
よれば、底質内の有機物含有量を原位置のまま低下させ
るものであるため、従来の覆砂工法のように良質砂を必
要としないことはもちろん、底質内の有機物が良質砂を
介して一定時間経過後に溶出したり、従来の浚渫工法の
ように浚渫された土の処理に困るといった事態も生じな
い。Further, according to the method for modifying the sediment according to the present embodiment, since the organic matter content in the sediment is reduced in situ, high quality sand is removed as in the conventional sand covering method. Needless to say, the organic matter in the sediment does not elute through the high-quality sand after a certain period of time, and there is no problem that the dredged soil is troubled as in the conventional dredging method.
【００５３】特に、本実施形態に係る底質の改質方法に
よれば、植物プランクトンが光合成を盛んに行って酸素
を供給している昼間にアンモニア態窒素の硝化及び硫化
水素の酸化を行い、酸素供給が不足する夜間に硝酸態窒
素を脱窒菌によって窒素ガスに変化させるようにしたの
で、底質の改質処理をきわめて合理的かつ短期間に行う
ことが可能となる。In particular, according to the method for modifying sediment according to the present embodiment, nitrification of ammonia nitrogen and oxidation of hydrogen sulfide are performed during daytime when phytoplankton actively performs photosynthesis and supplies oxygen, Since nitrate nitrogen is changed into nitrogen gas by denitrifying bacteria during the night when the oxygen supply is insufficient, it is possible to perform the sediment reforming treatment extremely rationally and in a short time.
【００５４】また、本実施形態においては、攪拌浮上作
業による水質汚濁や表層貧酸素化によって海洋生物の死
滅を招くおそれがある。かかる場合には、第１実施形態
と同様、重り１１を付けた４枚の可搬性プラスチック板
１２をボックス状に底質２の上に立設して閉鎖水域１３
を構成すればよいが、その構成や手順については、第１
実施形態と同様であるので、ここではその説明を省略す
る。Further, in this embodiment, there is a possibility that marine organisms may be killed due to water pollution or surface hypoxia caused by the stirring and floating operation. In such a case, as in the first embodiment, four portable plastic plates 12 with weights 11 are erected in a box shape on the sediment 2 to form a closed water area 13.
May be configured, but the configuration and procedure are described in the first section.
Since it is the same as the embodiment, the description thereof is omitted here.
【００５５】[0055]
【発明の効果】以上述べたように、本発明に係る底質の
改質方法によれば、アンモニア態窒素の形で底質に含ま
れている窒素を攪拌浮上させて表層付近で硝化すること
により、いったん硝酸態窒素へと変化させ、次いで、該
硝酸態窒素の形で沈降した底質を貧酸素化している表層
に再び攪拌浮上させることによって今度は脱窒菌の作用
で窒素ガスへと変化させるようにしたので、底質に含ま
れる窒素を窒素ガスの形で確実に大気に放出させること
が可能となり、かくして根本的な底質の改質を行うこと
が可能となる。As described above, according to the method for reforming sediment according to the present invention, nitrogen contained in sediment in the form of ammonia nitrogen is stirred and floated to be nitrified near the surface layer. Once, the sediment sedimented in the form of nitrate nitrogen was stirred and floated again on the deoxygenated surface layer, and then changed to nitrogen gas by the action of denitrifying bacteria. As a result, it is possible to reliably release nitrogen contained in the sediment into the atmosphere in the form of nitrogen gas, and thus it is possible to fundamentally reform the sediment.
【００５６】[0056]
【図１】第１実施形態に係る底質の改質方法を行ってい
る様子を示した作業手順図。FIG. 1 is a work procedure diagram showing a state in which a method for reforming sediment according to a first embodiment is performed.
【図２】変形例に係る底質の改質方法を行っている様子
を示した作業図。FIG. 2 is a work diagram showing a state in which a method for modifying sediment according to a modified example is performed.
【図３】第２実施形態に係る底質の改質方法を行ってい
る様子を示した作業手順図。FIG. 3 is a work procedure diagram showing a state in which a method for reforming sediment according to a second embodiment is performed.
１ 海底（水底） ２ 底質 ３ 表層 １２ 可搬性プラスチック板
（不透水性材料） １３ 閉鎖性水域Reference Signs List 1 sea bottom (water bottom) 2 sediment 3 surface layer 12 portable plastic plate (impermeable material) 13 closed water area
Claims (5)
を表層付近まで攪拌浮上させた後、沈降した底質を再び
表層付近まで攪拌浮上させることを特徴とする底質の改
質方法。1. A method of improving bottom sediment, wherein sediment deposited on the bottom of a sea, lake, marsh, river or the like is stirred and floated to near the surface layer, and the sediment sediment is stirred and floated again to near the surface layer. Method.
項１記載の底質の改質方法。2. The method according to claim 1, wherein the floating of the sediment is repeatedly performed.
請求項２記載の底質の改質方法。3. The method for reforming sediment according to claim 1, wherein the stirring and floating are performed at night.
を昼間に表層近傍まで攪拌浮上させ、沈降した底質を再
び夜間に表層付近まで攪拌浮上させることを特徴とする
底質の改質方法。4. A sediment characterized in that sediment deposited on the bottom of the sea, lake, marsh, river, etc. is stirred and floated to near the surface in the daytime, and sedimented sediment is again stirred and floated to near the surface in the night. Reforming method.
びる不透水性材料を壁状に配置して閉鎖水域を形成し、
該閉鎖水域内で前記攪拌浮上作業を行う請求項１乃至請
求項４のいずれか一記載の底質の改質方法。5. A closed water body is formed by arranging a water-impermeable material extending from the bottom of a sea, lake, marsh or river to the water surface in a wall shape,
The method according to any one of claims 1 to 4, wherein the stirring and floating operation is performed in the closed water area.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000286444A JP2002088732A (en) | 2000-09-21 | 2000-09-21 | Bottom quality improving method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000286444A JP2002088732A (en) | 2000-09-21 | 2000-09-21 | Bottom quality improving method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002088732A true JP2002088732A (en) | 2002-03-27 |
Family
ID=18770363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000286444A Pending JP2002088732A (en) | 2000-09-21 | 2000-09-21 | Bottom quality improving method |
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| Country | Link |
|---|---|
| JP (1) | JP2002088732A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004261732A (en) * | 2003-03-03 | 2004-09-24 | Ube Material Industries Ltd | Method for inhibiting generation of algae in freshwater area |
| CN109111065A (en) * | 2018-08-07 | 2019-01-01 | 上海久树环境科技有限公司 | A kind of riverbed ecology synthesis restorative procedure |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02160098A (en) * | 1988-12-12 | 1990-06-20 | Yoshida Sogo Kenkyusho:Kk | Sludge cleaning method |
| JPH0383695U (en) * | 1990-06-15 | 1991-08-26 | ||
| JP2000254696A (en) * | 1999-03-10 | 2000-09-19 | Ohbayashi Corp | Method for reforming bottom mud and system therefor |
-
2000
- 2000-09-21 JP JP2000286444A patent/JP2002088732A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02160098A (en) * | 1988-12-12 | 1990-06-20 | Yoshida Sogo Kenkyusho:Kk | Sludge cleaning method |
| JPH0383695U (en) * | 1990-06-15 | 1991-08-26 | ||
| JP2000254696A (en) * | 1999-03-10 | 2000-09-19 | Ohbayashi Corp | Method for reforming bottom mud and system therefor |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004261732A (en) * | 2003-03-03 | 2004-09-24 | Ube Material Industries Ltd | Method for inhibiting generation of algae in freshwater area |
| JP4550366B2 (en) * | 2003-03-03 | 2010-09-22 | 宇部マテリアルズ株式会社 | Method for controlling the generation of algae in freshwater areas |
| CN109111065A (en) * | 2018-08-07 | 2019-01-01 | 上海久树环境科技有限公司 | A kind of riverbed ecology synthesis restorative procedure |
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