JP6739815B1

JP6739815B1 - Dredging system

Info

Publication number: JP6739815B1
Application number: JP2019159229A
Authority: JP
Inventors: 透青井; 衛齋藤; 直之畑
Original assignee: 初雁興業株式会社
Priority date: 2019-09-02
Filing date: 2019-09-02
Publication date: 2020-08-12
Anticipated expiration: 2039-09-02
Also published as: JP2021038540A

Abstract

【課題】水質を大きく変化させずに重金属成分を除去もしくは不溶化して、水は貯水池に環流し底泥は培養土として回収する浚渫システムを提供する。【解決手段】この浚渫システム１００は、水中に溶出している重金属成分は多孔質鉄粒が捕集除去して環境基準値以下にするとともに底泥中の重金属成分は無機中性凝集剤が固定不溶化し外部への溶出を防止する。また、使用する無機中性凝集剤は添加の前後で水質を大きく変化させず、また動植物に有害な成分を含有しない。よって、この浚渫システム１００により分離した上澄み水は浚渫した貯水池にそのまま放流することが可能であり、貯水池の機能を維持したまま浚渫作業を行うことができる。また、浚渫により生じた脱水底泥は重金属成分が溶出しないため植物栽培用の培養土として使用することができる。【選択図】図１PROBLEM TO BE SOLVED: To provide a dredging system in which heavy metal components are removed or insolubilized without largely changing the water quality, water is circulated to a reservoir and bottom mud is recovered as culture soil. SOLUTION: In this dredging system 100, a heavy metal component eluted in water is collected and removed by a porous iron particle so as to be below an environmental standard value, and a heavy metal component in bottom mud is fixed by an inorganic neutral coagulant. It becomes insoluble and prevents elution to the outside. In addition, the inorganic neutral coagulant used does not significantly change the water quality before and after addition, and does not contain components harmful to plants and animals. Therefore, the supernatant water separated by the dredging system 100 can be directly discharged to the dredged reservoir, and the dredging work can be performed while maintaining the function of the reservoir. In addition, the dehydrated bottom mud produced by dredging can be used as a culture soil for plant cultivation because heavy metal components do not elute. [Selection diagram] Figure 1

Description

本発明は、貯水池の底に溜まった底泥を水ごと吸引して、重金属成分を除去及び不溶化した後、底泥を分離回収する浚渫システムに関するものである。 The present invention relates to a dredging system for sucking bottom mud accumulated at the bottom of a reservoir together with water to remove and insolubilize heavy metal components, and then separate and collect bottom mud.

従来、湖沼や堀、人工池、農業用ため池等の貯水池には、土や砂、ゴミ、ヘドロ等の底泥が徐々に堆積してゆく。これら、底泥の堆積は貯水池の水深を浅くして貯水池本来の機能を低下させる他、水質の悪化を引き起こす一因となる。よって、これら底泥を除去する浚渫を定期的に行うことが好ましい。 BACKGROUND ART Conventionally, bottom mud such as soil, sand, dust, and sludge gradually accumulates in reservoirs such as lakes, moats, artificial ponds, and agricultural ponds. Such sedimentation of bottom mud not only reduces the original function of the reservoir by making it shallower but also contributes to the deterioration of water quality. Therefore, it is preferable to regularly perform dredging to remove these bottom mud.

従来の貯水池の浚渫は、貯水池の水を抜いた上で重機等により行うことが一般的であった。しかしながら、この手法では貯水池への水の遮水と貯水池の水の排水が必要となり、何らかの土木工事が必要であるとともに作業期間が長く、コスト高であるという問題点がある。また、浚渫作業中には貯水池を使用できないという問題点がある。さらに、貯水池の水が抜き取られるため、貯水池に生息する水生動植物が死滅し、貯水池の生態系に多大な悪影響を与えるという問題点がある。 Conventional dredging of a reservoir has generally been carried out using heavy equipment after draining the reservoir. However, with this method, it is necessary to block water from the reservoir and drain the water from the reservoir, which necessitates some kind of civil engineering work, requires a long working period, and is costly. There is also a problem that the reservoir cannot be used during the dredging work. Further, since water in the reservoir is extracted, aquatic plants and animals inhabiting the reservoir are killed, which has a serious adverse effect on the ecosystem of the reservoir.

この問題点に対し、本願発明者らは下記［特許文献１］に示す湖沼水の浚渫システムに関する発明を行った。この［特許文献１］に記載の発明は、貯水池の水面に浮かべた台船から送水ポンプを吊下げ、この送水ポンプで底泥を吸引し浚渫を行う。このため、貯水池の遮水作業、排水作業が不要で、作業期間の短縮と、抵コスト化とを実現することができる。また、貯水池の水を抜き取ることなく浚渫を行うことが可能なため、貯水池に生息する動植物の生態系を維持することができる。さらに、［特許文献１］に記載の発明ではカルシウムを主成分とした無機中性凝集剤を用いているため、分離回収した底泥を培養土としてそのまま植物栽培に使用することができる。 With respect to this problem, the inventors of the present application have made an invention relating to a dredging system for lake water shown in [Patent Document 1] below. In the invention described in [Patent Document 1], a water pump is suspended from a barge floated on the water surface of a reservoir, and this water pump sucks bottom mud to perform dredging. Therefore, it is possible to reduce the work period and reduce the cost because the work of blocking the water and the work of draining the reservoir are unnecessary. In addition, since dredging can be performed without draining water from the reservoir, it is possible to maintain the ecosystem of plants and animals that inhabit the reservoir. Furthermore, in the invention described in [Patent Document 1], since the inorganic neutral coagulant containing calcium as a main component is used, the separated and recovered bottom mud can be directly used as plant soil for plant cultivation.

しかしながら、ヒ素等の重金属成分を多く含む水や土砂が流入したり、自然由来にて生じた重金属成分が存在する貯水池では、この重金属成分の濃度が環境基準を超える場合がある。このような貯水池を浚渫して回収した底泥は重金属成分を多く含むため土壌汚染防止法により植物の培養土には使用できず、産業廃棄物として処分する必要があり、処理コストが掛るという問題点が有る。この問題点に対し下記［特許文献２］には泥水中に１５０μｍ〜３００μｍの鉄粉を混合して泥水中に溶出した重金属成分を吸着した後、鉄粉を重金属成分ごと分離して除去する重金属汚染土壌の無害化処理システムに関する発明が開示されている。 However, the concentration of this heavy metal component may exceed the environmental standard in a reservoir in which water or earth and sand containing a large amount of heavy metal components such as arsenic flows in, or where there are heavy metal components derived from nature. Since the bottom mud collected by dredging such a reservoir contains a large amount of heavy metal components, it cannot be used for plant cultivation soil according to the Soil Contamination Prevention Law and must be disposed of as industrial waste, resulting in high treatment costs. There is a point. In order to solve this problem, the following [Patent Document 2] describes a heavy metal in which mud water is mixed with iron powder of 150 μm to 300 μm to adsorb heavy metal components eluted in the mud, and then iron powder is separated and removed together with the heavy metal components. An invention relating to a detoxification treatment system for contaminated soil is disclosed.

また、例えば下記［特許文献３］では、凝集物の脱水ケーキからの金属類の溶出を抑制する無機中性凝集剤に関する発明が開示されている。 Further, for example, the following [Patent Document 3] discloses an invention relating to an inorganic neutral coagulant that suppresses the elution of metals from the dehydrated cake of the coagulated product.

特開第６３５９９０２号公報Japanese Patent Laid-Open No. 6359902 特開２０１７−１４８７６０号公報JP, 2017-148760, A 特開第２７７４０９６号公報JP-A-2774096

上記の［特許文献２］に記載の発明は、泥水中の鉄粉を磁性を用いて分離する。しかしながら、この磁性を用いた分離方法は効率が悪く、大量の水を底泥ごと吸引して処理する［特許文献１］に記載の発明には適用することができない。また、［特許文献２］に記載の発明では土中の（水中に溶出していない）重金属成分を除去するために、水のｐＨ調整を行って土中の重金属成分を水中に溶出させる必要がある。しかしながら［特許文献１］に記載の発明では、底泥を分離した後の水を貯水池に戻すことで生態系の維持を図る。このため、ｐＨ調整等の水質を変化させる薬剤を添加することができず、よって［特許文献２］に記載の技術を［特許文献１］に記載の発明に適用することができない。 The invention described in the above [Patent Document 2] separates iron powder in mud water using magnetism. However, this separation method using magnetism is inefficient and cannot be applied to the invention described in [Patent Document 1] in which a large amount of water is sucked and treated together with the bottom mud. In addition, in the invention described in [Patent Document 2], in order to remove heavy metal components in soil (not dissolved in water), it is necessary to adjust pH of water to dissolve heavy metal components in soil into water. is there. However, in the invention described in [Patent Document 1], the water after separating the bottom mud is returned to the reservoir to maintain the ecosystem. For this reason, it is not possible to add a chemical that changes the water quality such as pH adjustment, and thus the technique described in [Patent Document 2] cannot be applied to the invention described in [Patent Document 1].

本発明は上記事情に鑑みてなされたものであり、水質を大きく変化させずに重金属成分を除去もしくは不溶化して、水は貯水池に環流し底泥は培養土として回収する浚渫システムの提供を目的とする。 The present invention has been made in view of the above circumstances, and an object thereof is to provide a dredging system in which heavy metal components are removed or insolubilized without significantly changing the water quality, water is circulated to a reservoir, and bottom mud is recovered as culture soil. And

本発明は、
（１）底泥を水ごと吸引して底泥スラリとして圧送する送水ポンプ２０と、前記底泥スラリに凝集剤を添加して前記底泥を凝集沈降させる凝集分離槽５０と、前記凝集剤によって凝集沈降した底泥を脱水する脱水部８０と、を有する浚渫システムにおいて、
サイクロン型の遠心分離装置を備え前記送水ポンプ２０で圧送された底泥スラリから重量物及び夾雑物を除去するスラリ分離部（遠心分離部３０及び夾雑物選別部４０）と、
前記スラリ分離部を通過した底泥スラリに比表面積が０．１２ｍ^２／ｇ〜０．３６ｍ^２／ｇ、見掛密度が１．３ｇ／ｃｍ^３〜１．５ｇ／ｃｍ^３で、サイクロン型の遠心分離装置にて分離が可能な粒径０．１ｍｍ〜１ｍｍの多孔質鉄粒を添加して攪拌し、前記底泥スラリ中に溶出している重金属成分を前記多孔質鉄粒に吸着させる鉄粒混合部７０と、
前記多孔質鉄粒を重金属成分ごと前記スラリ分離部の遠心分離装置と同様の１台のサイクロン型の遠心分離装置により分離して、分離後の底泥スラリを前記凝集分離槽５０に送出する鉄粒遠心分離部７６と、をさらに有し、
前記凝集剤が凝集後の底泥中の固体の重金属成分の溶出を抑制し且つ水のｐＨを変化させない石膏を主成分とした無機中性凝集剤であり、
さらに、前記鉄粒混合部７０が、底泥スラリに前記多孔質鉄粒を添加する鉄粒添加槽７２ａと、多孔質鉄粒と底泥スラリとを攪拌しながら維持する鉄粒混合槽７２ｂと、を有し、前記鉄粒添加槽７２ａと鉄粒混合槽７２ｂとは、各槽の下方に位置する連結管によって直列に連結され、前記鉄粒混合槽７２ｂの連結数によって底泥スラリの停留時間を調節することを特徴とする浚渫システム１００を提供することにより、上記課題を解決する。
（２）鉄粒遠心分離部７６が鉄粒添加槽７２ａの上方に位置し、分離した多孔質鉄粒を前記鉄粒添加槽７２ａに排出することを特徴とする上記（１）記載の浚渫システム１００を提供することにより、上記課題を解決する。
（３）スラリ分離部から鉄粒混合部７０までの底泥スラリの搬送を送水ポンプ２０による圧送と自然流下によって行い、鉄粒混合部７０から脱水部８０までの底泥スラリの搬送を鉄粒遠心分離部７６に底泥スラリを搬送する第２送水ポンプ７４による圧送と自然流下によって行うことを特徴とする上記（１）または（２）に記載の浚渫システム１００を提供することにより、上記課題を解決する。
（４）無機中性凝集剤として、アルミナ・ケイ酸塩を主体とする天然鉱物３０〜５０重量％と硫酸カルシウム４５〜６５重量％と有機系凝集剤１〜５重量％とから成る主成分１００重量部に対し、硫酸アルミニウム３０〜５０重量部、塩化アルミニウム５〜１０重量部、およびアルカリ金属炭酸塩２０〜４０重量部が配合されたものを用いることを特徴とする上記（１）乃至（３）のいずれかに記載の浚渫システム１００を提供することにより、上記課題を解決する。 The present invention is
(1) A water feed pump 20 that sucks bottom mud together with water and feeds it as bottom mud slurry, a coagulation separation tank 50 that adds a coagulant to the bottom mud slurry to coagulate and settle the bottom mud, and the coagulant In a dredging system having a dehydration unit 80 for dehydrating coagulated sedimented bottom mud,
A slurry separation unit (centrifugal separation unit 30 and foreign matter selection unit 40) that includes a cyclone type centrifugal separation device and removes heavy substances and foreign substances from the bottom mud slurry pumped by the water pump 20.
Specific surface area sediment slurry passing through the slurry separation unit at 0.12m ^² /g~0.36m ² / g, apparent density ^{^{1.3g / cm 3 ~1.5g / cm 3}} , the cyclone Iron for adsorbing heavy metal components eluted in the bottom mud slurry to the porous iron particles by adding porous iron particles having a particle size of 0.1 mm to 1 mm that can be separated by a centrifuge and stirring the mixture A grain mixing section 70,
Iron for separating the porous iron particles together with heavy metal components by a single cyclone type centrifugal separator similar to the centrifugal separator of the slurry separator, and sending the separated bottom mud slurry to the coagulation/separation tank 50. And a grain centrifugal separation unit 76,
The coagulant Ri inorganic neutral coagulant der the plaster does not change the pH of suppressing and water elution of heavy metal components of the solid bottom mud as a main component after coagulation,
Furthermore, the iron particle mixing section 70, the iron particle addition tank 72a for adding the porous iron particles to sediment slurry, iron particle mixing tank 72b to keep stirring the porous iron particles and sediments slurry , And the iron particle addition tank 72a and the iron particle mixing tank 72b are connected in series by a connecting pipe located below each tank, and the bottom mud slurry is retained depending on the number of the iron particle mixing tanks 72b connected. by providing a dredging system 100 you and adjusting the time, to solve the above problems.
( 2 ) The iron particle centrifugal separation unit 76 is located above the iron particle addition tank 72a, and the separated porous iron particles are discharged to the iron particle addition tank 72a. ( 1 ) The dredging system described in ( 1 ) above. By providing 100, the said subject is solved.
( 3 ) The bottom mud slurry is conveyed from the slurry separating section to the iron particle mixing section 70 by pressure feeding by the water pump 20 and gravity flow, and the bottom mud slurry is conveyed from the iron particle mixing section 70 to the dewatering section 80. By providing the dredging system 100 according to (1) or (2) above, which is performed by pressure feeding by the second water feed pump 74 that conveys the bottom mud slurry to the centrifugal separator 76 and natural flow. To solve.
( 4 ) As an inorganic neutral coagulant, a main component 100 composed of 30 to 50% by weight of a natural mineral mainly composed of alumina/silicate, 45 to 65% by weight of calcium sulfate, and 1 to 5% by weight of an organic coagulant. 30 to 50 parts by weight of aluminum sulfate, 5 to 10 parts by weight of aluminum chloride, and 20 to 40 parts by weight of alkali metal carbonate are blended with respect to parts by weight, and the above (1) to ( 3 ) are used. By providing the dredging system 100 described in any one of (1) to (4), the above-mentioned problems are solved.

本願発明の浚渫システムは、水中に溶出している重金属成分に関しては多孔質鉄粒が捕集除去する。また、底泥中の重金属成分は無機中性凝集剤が固定不溶化し外部への溶出を防止する。さらに、本願発明が使用する無機中性凝集剤は添加の前後で水質を大きく変化させず、また動植物に有害な成分を含有しない。よって、本願発明の浚渫システムにより分離した水は貯水池にそのまま放流することが可能であり、貯水池の機能を維持したまま浚渫作業を行うことができる。また、貯水池に生息する動植物の生態系を維持することができる。また、浚渫により生じた脱水底泥は重金属成分が溶出しないため植物栽培用の培養土として使用することができる。これにより、環境に対する負荷を軽減することができる。また、本発明に係る浚渫システムは、多孔質鉄粒の分離を遠心分離装置のみで行う。これにより、多孔質鉄粒の分離を短時間で効率良く行う事が可能となり、底泥スラリに対する高い処理能力を有する。 The dredging system of the present invention collects and removes the heavy iron components dissolved in water by the porous iron particles. In addition, the heavy metal component in the bottom mud is fixed and insoluble by the inorganic neutral coagulant to prevent elution to the outside. Furthermore, the inorganic neutral coagulant used in the present invention does not significantly change the water quality before and after the addition, and does not contain components harmful to plants and animals. Therefore, the water separated by the dredging system of the present invention can be discharged to the reservoir as it is, and the dredging work can be performed while maintaining the function of the reservoir. In addition, the ecosystem of plants and animals that inhabit the reservoir can be maintained. In addition, the dehydrated bottom mud produced by dredging can be used as a culture soil for plant cultivation because heavy metal components do not elute. This can reduce the load on the environment. Further, the dredging system according to the present invention separates the porous iron particles only by the centrifugal separator. This makes it possible to efficiently separate the porous iron particles in a short time, and has a high treatment capacity for the bottom mud slurry.

本発明に係る浚渫システムを示す図である。It is a figure which shows the dredging system which concerns on this invention. 本発明に係る浚渫システムの送水ポンプ及び台船を示す図である。It is a figure showing a water pump and a pontoon of a dredging system concerning the present invention. 多孔質鉄粒の攪拌時間とヒ素の濃度の関係を示すグラフである。6 is a graph showing the relationship between the stirring time of porous iron particles and the concentration of arsenic. 本発明に係る浚渫システムの脱水部を示す図である。It is a figure which shows the dewatering part of the dredging system which concerns on this invention. 各処理条件における上澄み液のヒ素濃度と脱水底泥の溶出試験結果を示す表である。It is a table which shows the arsenic concentration of the supernatant liquid and the elution test result of the dehydrated bottom mud under each treatment condition.

本発明に係る浚渫システム１００の実施の形態について図面に基づいて説明する。図１に示す本発明に係る浚渫システム１００は、基本構成として、貯水池の底泥を水ごと吸引して底泥スラリとして圧送する送水ポンプ２０と、この送水ポンプ２０により搬送される底泥スラリから底泥を分離回収する分離処理装置９０と、を有している。そして、分離処理装置９０は、送水ポンプ２０によって搬送される底泥スラリ中の砂や小石等の重量物を遠心分離により除去する遠心分離部３０と、この遠心分離部３０を通過した底泥スラリから植物片やゴミ等の夾雑物を除去する夾雑物選別部４０と、この夾雑物選別部４０を通過した底泥スラリ中に多孔質鉄粒を添加混合してスラリ中に溶出した重金属成分を吸着捕集する鉄粒混合部７０と、この多孔質鉄粒を重金属成分ごと遠心分離により分離する鉄粒遠心分離部７６と、この鉄粒遠心分離部７６で分離した底泥スラリに無機中性凝集剤を添加し底泥を凝集沈降させる凝集分離槽５０と、この凝集分離槽５０で凝集沈降した底泥（凝集底泥）を濃縮する濃縮槽６０と、この濃縮槽６０で濃縮された底泥（濃縮底泥）を脱水する脱水部８０と、を有している。尚、このうち、遠心分離部３０と夾雑物選別部４０とが本願発明のスラリ分離部を構成する。 An embodiment of a dredging system 100 according to the present invention will be described with reference to the drawings. The dredging system 100 according to the present invention shown in FIG. 1 has, as a basic configuration, a water feed pump 20 that sucks the bottom mud of a reservoir together with water and pressure-feeds it as bottom mud slurry, and a bottom mud slurry conveyed by the water feed pump 20. And a separation treatment device 90 that separates and collects the bottom mud. Then, the separation treatment device 90 includes a centrifugal separation unit 30 that removes heavy substances such as sand and pebbles in the bottom mud slurry conveyed by the water pump 20 by centrifugation, and a bottom mud slurry that has passed through the centrifugal separation unit 30. A contaminant sorting unit 40 that removes contaminants such as plant fragments and dust from the soil, and porous iron particles are added to and mixed with the bottom mud slurry that has passed through the contaminant sorting unit 40 to remove heavy metal components eluted in the slurry. An iron particle mixing section 70 for adsorption and collection, an iron particle centrifugal separation section 76 for separating the porous iron particles together with heavy metal components by centrifugation, and an inorganic neutral in the bottom mud slurry separated by the iron particle centrifugal separation section 76. A flocculating/separating tank 50 for adding a flocculant to coagulate and settle the bottom mud, a concentrating tank 60 for concentrating the bottom mud coagulated and settling in the coagulating/separating tank 50, and a bottom concentrated in the concentrating tank 60. And a dehydrating section 80 for dehydrating mud (concentrated bottom mud). Of these, the centrifugal separation unit 30 and the foreign matter selection unit 40 constitute the slurry separation unit of the present invention.

次に、本発明に係る浚渫システム１００に好適な送水ポンプ２０の一具体例の構成を図２の部分断面図を用いて説明する。本発明に好適な送水ポンプ２０は、１％〜２０％程度のＳＳ濃度（浮遊物質濃度）のスラリを圧送可能なものであり、モータを内蔵し防水性を有するポンプ本体部２１と、このポンプ本体部２１の下部に設置されたケーシング２２と、このケーシング２２内に設置されモータによって回転動作するインペラ２３と、ケーシング２２の取水口に設置されたカッタ２４と、モータによって回転動作し斜め下方を向いた羽根を複数備えた攪拌羽根２６と、ケーシング２２の下方に延びた脚部２８と、を有している。また、ケーシング２２からはホース接続端２２ａが伸び、このホース接続端２２ａに送水ホース１２の一端が接続する。そして、送水ポンプ２０は貯水池の水面に浮いた台船１０から適宜水中に吊下げて使用し、送水ポンプ２０で吸引された底泥スラリは送水ホース１２によって分離処理装置９０に搬送される。また、送水ポンプ２０の電源ケーブル１５ａは、送水ホース１２に沿って陸上まで延伸され、分離処理装置９０側の図示しない送水ポンプ制御盤を介して発電機等の電源に接続される。 Next, the configuration of a specific example of the water pump 20 suitable for the dredging system 100 according to the present invention will be described with reference to the partial cross-sectional view of FIG. A water supply pump 20 suitable for the present invention is capable of pressure-feeding a slurry having an SS concentration (suspended substance concentration) of about 1% to 20%, a pump main body 21 having a built-in motor and waterproofness, and this pump. A casing 22 installed in the lower portion of the main body 21, an impeller 23 installed in the casing 22 and rotated by a motor, a cutter 24 installed at an intake port of the casing 22, and a diagonally downward operation by a motor. It has a stirring blade 26 having a plurality of facing blades, and a leg portion 28 extending below the casing 22. A hose connection end 22a extends from the casing 22, and one end of the water supply hose 12 is connected to the hose connection end 22a. Then, the water supply pump 20 is used by appropriately suspending it from the pontoon 10 floating on the water surface of the reservoir in water, and the bottom mud slurry sucked by the water supply pump 20 is conveyed to the separation treatment device 90 by the water supply hose 12. The power supply cable 15a of the water supply pump 20 extends to the land along the water supply hose 12 and is connected to a power source such as a generator via a water supply pump control panel (not shown) on the separation treatment device 90 side.

送水ホース１２は送水ポンプ２０と接続可能であれば如何なるものを用いても良いが、内径６５ｍｍ程度のものを用いることが好ましい。また、送水ホース１２にはフロート１８が所定の間隔で設置され、電源ケーブル１５ａ（１５ｂ）とともに貯水池の水面に支持される。 Any water supply hose 12 may be used as long as it can be connected to the water supply pump 20, but it is preferable to use one having an inner diameter of about 65 mm. Further, floats 18 are installed on the water supply hose 12 at predetermined intervals, and are supported on the water surface of the reservoir together with the power cables 15a (15b).

また、台船１０は送水ポンプ２０及び作業者を搭載しても貯水池の水面に浮く十分なフロートを備え、台船１０の略中央部分には送水ポンプ２０を貯水池内に昇降する昇降口１１を有している。また、昇降口１１の上部には送水ポンプ２０を吊下げる櫓１４が設置され、この櫓１４の上部には送水ポンプ２０を昇降する昇降機１６が設置されている。尚、昇降機１６の電源ケーブル１５ｂは、送水ポンプ２０の電源ケーブル１５ａとともに送水ホース１２に沿って陸上まで延伸され図示しない電源に接続される。 In addition, the pontoon 10 is provided with a water pump 20 and a sufficient float that floats on the water surface of the reservoir even if a worker is mounted, and an elevating port 11 for raising and lowering the water pump 20 into the reservoir is provided at a substantially central portion of the pedestal 10. Have Further, a turret 14 for suspending the water supply pump 20 is installed above the elevating port 11, and an elevator 16 for elevating the water supply pump 20 is installed above the turret 14. The power cable 15b of the elevator 16 is extended to the land along the water hose 12 along with the power cable 15a of the water pump 20 and connected to a power source (not shown).

次に、分離処理装置９０の構成を図１を用いて説明する。先ず、分離処理装置９０の遠心分離部３０は、周知のサイクロン型の遠心分離装置であり、外筒３２ａと内筒３２ｂとを有している。そして、外筒３２ａの上部には送水ホース１２が横方向に向けて接続する。また、外筒３２ａの下部はホッパ部３４となっており、ホッパ部３４には開閉コック３６ａにより開閉する排出口３６が設置されている。そして、内筒３２ｂには夾雑物選別部４０と繋がる配管５ａが接続されている。尚、分離処理装置９０の各部を繋ぐ配管５ａ〜５ｄ及び水配管７ａ、７ｂとしては、ホースや金属配管等の周知の配管設備を用いることができる。 Next, the configuration of the separation processing device 90 will be described with reference to FIG. First, the centrifugal separation unit 30 of the separation processing device 90 is a known cyclone type centrifugal separation device, and has an outer cylinder 32a and an inner cylinder 32b. The water supply hose 12 is connected to the upper part of the outer cylinder 32a in the lateral direction. The lower part of the outer cylinder 32a is a hopper portion 34, and the hopper portion 34 is provided with a discharge port 36 which is opened and closed by an opening/closing cock 36a. A pipe 5a connected to the foreign matter selection unit 40 is connected to the inner cylinder 32b. As the pipes 5a to 5d and the water pipes 7a and 7b that connect the respective parts of the separation treatment device 90, well-known pipe facilities such as hoses and metal pipes can be used.

また、夾雑物選別部４０は、底泥スラリ中の夾雑物を取り除く夾雑物選別装置４２を有している。この夾雑物選別装置４２としては、所定の大きさ以上の夾雑物を取り除くことが可能であれば如何なる装置を用いても良いが、２ｍｍ程度のスリットを有する周知のベルトスクリーンを用いることが特に好ましい。また、夾雑物選別部４０には流量測定升４４を設け、送水ポンプ２０が吸引する底泥スラリの流量を確認可能とすることが好ましい。 Further, the foreign matter sorting unit 40 has a foreign matter sorting device 42 that removes foreign matters in the bottom mud slurry. As the foreign matter sorting device 42, any device may be used as long as it is possible to remove foreign substances of a predetermined size or more, but it is particularly preferable to use a well-known belt screen having a slit of about 2 mm. .. Further, it is preferable that a flow rate measuring box 44 is provided in the foreign matter sorting section 40 so that the flow rate of the bottom mud slurry sucked by the water pump 20 can be confirmed.

また、鉄粒混合部７０は、前述のように底泥スラリ中に多孔質鉄粒を添加して攪拌し、底泥スラリ中に溶出している重金属成分を多孔質鉄粒に吸着させるためのものであり、多孔質鉄粒を添加する鉄粒添加槽７２ａと、多孔質鉄粒と底泥スラリとを攪拌しながら維持する鉄粒混合槽７２ｂと、の複数の槽で構成する。尚、このように鉄粒添加槽７２ａと鉄粒混合槽７２ｂとを分けることで、十分な重金属成分の吸着時間が確保でき、水中に溶出した重金属成分の捕集を効率的に行うことができる。そして、鉄粒混合槽７２ｂ及び各鉄粒混合槽７２ｂには、底泥スラリと多孔質鉄粒とを混合攪拌する周知の攪拌装置５２を有する。また、最も下流に位置する鉄粒混合槽７２ｂには第２送水ポンプ７４が接続し、この最下流に位置する鉄粒混合槽７２ｂ内の底泥スラリを多孔質鉄粒ごと吸引し送水ホース１２ａを介して鉄粒遠心分離部７６に圧送する。 In addition, the iron particle mixing unit 70 adds the porous iron particles to the bottom mud slurry and stirs them as described above to adsorb the heavy metal component eluted in the bottom mud slurry to the porous iron particles. are those, iron particle addition tank 72a of adding a porous iron particles, iron particles mixing tank 72b to keep stirring the porous iron particles and sediment slurry, that make up a plurality of tanks of. By separating the iron particle addition tank 72a and the iron particle mixing tank 72b in this way, a sufficient adsorption time of heavy metal components can be secured, and the heavy metal components eluted in water can be efficiently collected. .. The iron particle mixing tank 72b and each iron particle mixing tank 72b have a known stirring device 52 for mixing and stirring the bottom mud slurry and the porous iron particles. Further, the second water supply pump 74 is connected to the iron particle mixing tank 72b located at the most downstream side, and the bottom mud slurry in the iron particle mixing tank 72b located at the most downstream side is sucked together with the porous iron particles to supply the water hose 12a. It is pressure-fed to the iron particle centrifugal separation unit 76 via.

ここで、本発明に係る浚渫システム１００で使用する多孔質鉄粒とは、水中に溶出している重金属成分（カドミウム、クロム、セレン、鉛、ヒ素、フッ素、ホウ素等やその化合物）を吸着可能な多数の微細孔を表面に有する鉄材の顆粒であり、例えば比表面積が０．１２ｍ^２／ｇ〜０．３６ｍ^２／ｇ、見掛密度が１．３ｇ／ｃｍ^３〜１．５ｇ／ｃｍ^３のものを用いる。また、形状に関しては球、フレーク状、塊状、如何なるものを用いても構わない。ただし、その粒径はサイクロン型の遠心分離装置にて分離が可能な０．１ｍｍ〜１ｍｍの範囲内のものを用いる。 Here, the porous iron particles used in the dredging system 100 according to the present invention are capable of adsorbing heavy metal components (cadmium, chromium, selenium, lead, arsenic, fluorine, boron, etc. and their compounds) eluted in water. a granulate of an iron material having a large number of micropores, such a surface, for example, a specific surface area of 0.12m ^² /g~0.36m ² / g, apparent density 1.3g ^/ cm ³ ~1.5g ^/ cm 3 Ru using things. As for the shape, any shape such as a sphere, a flake shape, or a lump shape may be used. However, the particle size used is within the range of 0.1 mm to 1 mm that can be separated by a cyclone type centrifugal separator.

ここで、底泥スラリ中に溶出しているヒ素の濃度（ｍｇ／Ｌ）と多孔質鉄粒の攪拌時間（処理時間：ｍｉｎ）との関係を図３のグラフに示す。尚、多孔質鉄粒の量は底泥スラリ１Ｌ当たり２０ｇとした。この図３のグラフから、多孔質鉄粒の攪拌時間、即ち底泥スラリと多孔質鉄粒との接触時間が長い程、重金属成分（ヒ素）の吸着捕集が進み、底泥スラリ中に溶出しているヒ素の濃度が低下することが判る。ここで、土壌汚染防止法におけるヒ素濃度の基準値は０．０１ｍｇ／Ｌ以下であるため、上記の条件では多孔質鉄粒の攪拌時間、即ち鉄粒混合部７０における底泥スラリの停留時間は４０分以上が必要であり、吸着がほぼ完了する９０分が好ましいことがわかる。尚、この鉄粒混合部７０での停留時間は底泥スラリ中に溶出している重金属成分の濃度によって変化する。よって、浚渫を行う貯水池ごとに測定等を行い、最適な停留時間を取得することが好ましい。 Here, the relationship between the concentration (mg/L) of arsenic eluted in the bottom mud slurry and the stirring time (treatment time: min) of the porous iron particles is shown in the graph of FIG. The amount of porous iron particles was 20 g per 1 L of bottom mud slurry. From the graph of FIG. 3, the longer the stirring time of the porous iron particles, that is, the longer the contact time between the bottom mud slurry and the porous iron particles, the more the heavy metal component (arsenic) is adsorbed and collected, and the elution into the bottom mud slurry occurs. It can be seen that the concentration of arsenic is decreasing. Here, since the standard value of the arsenic concentration in the Soil Contamination Prevention Law is 0.01 mg/L or less, the stirring time of the porous iron particles, that is, the staying time of the bottom mud slurry in the iron particle mixing section 70 is It can be seen that 40 minutes or more is required, and 90 minutes when adsorption is almost completed is preferable. The staying time in the iron grain mixing section 70 changes depending on the concentration of heavy metal components eluted in the bottom mud slurry. Therefore, it is preferable to perform measurement and the like for each reservoir in which dredging is performed to obtain the optimum dwell time.

ただし、鉄粒混合部７０での停留時間に合わせて底泥スラリの搬送量を設定すると、浚渫システム１００全体としての浚渫効率が低下する可能性が有る。よって、鉄粒混合部７０における停留時間の調整は鉄粒混合部７０（鉄粒添加槽７２ａ及び鉄粒混合槽７２ｂ）の容量にて行うことが好ましい。ただし、容量の異なる槽を複数準備するのは設備コストや保管スペースの面から好ましくない。よって、鉄粒混合槽７２ｂの連結個数により鉄粒混合部７０の容量を調整し目的の停留時間以上とする。尚、本例では浚渫システム１００の流量を約１０ｍ^３／ｈｒとし、容量５ｍ^３の鉄粒添加槽７２ａと鉄粒混合槽７２ｂとを全体で３台（鉄粒添加槽７２ａ×１台、鉄粒混合槽７２ｂ×２台：総容量１５ｍ^３）連結することで、鉄粒混合部７０での停留時間を９０分としている。
However, if the transport amount of the bottom mud slurry is set according to the dwell time in the iron particle mixing unit 70, the dredging efficiency of the dredging system 100 as a whole may be reduced. Therefore, it is preferable to adjust the dwell time in the iron particle mixing unit 70 by the capacity of the iron particle mixing unit 70 (the iron particle addition tank 72a and the iron particle mixing tank 72b). However, it is not preferable to prepare a plurality of tanks having different capacities in terms of equipment cost and storage space. Thus, the connection number of the iron particle mix tank 72b to adjust the volume of the iron particle mix section 70 shall be the least retention time of interest. In this example, the flow rate of the dredging system 100 is set to about 10 m ³ /hr, and the iron particle addition tank 72 a and the iron particle mixing tank 72 b having a capacity of 5 m ³ are provided in total of 3 units (the iron particle addition unit 72 a×1 unit Grain mixing tank 72b×2 units: total capacity 15 m ³ ) By connecting, the dwell time in the iron particle mixing unit 70 is set to 90 minutes.

また、鉄粒遠心分離部７６は遠心分離部３０と同様の周知のサイクロン型の遠心分離装置であり、外筒３２ａと内筒３２ｂとを有している。そして、鉄粒遠心分離部７６の外筒３２ａの上部には第２送水ポンプ７４から延びた送水ホース１２ａが横方向に向けて接続する。また、外筒３２ａの下部はホッパ部３４となっており、ホッパ部３４の先側には開閉コック３６ａにより開閉する排出口３６が設置されている。そして、内筒３２ｂには凝集分離槽５０へと繋がる配管５ｄが接続している。そして、比重の軽い底泥スラリは内筒３２ｂを通って凝集分離槽５０へ吐出され、比重の重い多孔質鉄粒は重金属成分を吸着したままホッパ部３４に沿って沈降堆積して排出口３６から排出される。このとき、鉄粒遠心分離部７６を鉄粒添加槽７２ａの上方に設けるとともに排出口３６を適宜開閉して、鉄粒遠心分離部７６で遠心分離した多孔質鉄粒を鉄粒添加槽７２ａに吐出して再利用することが好ましい。尚、多孔質鉄粒は複数回使用することで徐々に吸着能力が低下する。よって、例えば底泥スラリの累積処理水量もしくは累積処理時間もしくは再使用回数が予め設定された値を超えるなどして多孔質鉄粒の吸着能力が不十分となると、作業者は多孔質鉄粒の排出方向を鉄粒回収部７８側へ切り替える。これにより、多孔質鉄粒は鉄粒回収部７８へと排出され、重金属成分を吸着したまま法律に準拠した然るべき処理方法によって処分される。尚、処分される多孔質鉄粒の量は底泥の量に比較して少ないため、処分コストの削減を図ることができる。また、古い多孔質鉄粒が回収されると、鉄粒混合部７０には新たな多孔質鉄粒が供給される。 The iron particle centrifugal separation unit 76 is a known cyclone-type centrifugal separation device similar to the centrifugal separation unit 30, and has an outer cylinder 32a and an inner cylinder 32b. A water supply hose 12a extending from the second water supply pump 74 is connected to the upper portion of the outer cylinder 32a of the iron particle centrifugal separation unit 76 in the lateral direction. Further, a lower portion of the outer cylinder 32a is a hopper portion 34, and a discharge port 36 that is opened/closed by an opening/closing cock 36a is installed on the tip side of the hopper portion 34. A pipe 5d connected to the coagulation/separation tank 50 is connected to the inner cylinder 32b. Then, the bottom mud slurry having a low specific gravity is discharged to the coagulation/separation tank 50 through the inner cylinder 32b, and the porous iron particles having a high specific gravity settle and accumulate along the hopper portion 34 while adsorbing the heavy metal component, and then the discharge port 36. Emitted from. At this time, the iron particle centrifugal separation unit 76 is provided above the iron particle addition tank 72a, and the discharge port 36 is appropriately opened and closed so that the porous iron particles centrifugally separated by the iron particle centrifugal separation unit 76 are transferred to the iron particle addition tank 72a. It is preferable to discharge and reuse. It should be noted that the use of porous iron particles a plurality of times gradually reduces the adsorption capacity. Therefore, if the adsorption capacity of the porous iron particles becomes insufficient due to, for example, the accumulated treated water amount of the bottom mud slurry or the accumulated treatment time or the number of reuses exceeds a preset value, the worker will The discharge direction is switched to the iron particle recovery unit 78 side. As a result, the porous iron particles are discharged to the iron particle recovery section 78 and disposed of while adsorbing the heavy metal components by a proper processing method in compliance with the law. Since the amount of porous iron particles to be disposed is smaller than the amount of bottom mud, it is possible to reduce the disposal cost. Further, when the old porous iron particles are collected, new porous iron particles are supplied to the iron particle mixing section 70.

また、凝集分離槽５０は、鉄粒遠心分離部７６で分離した底泥スラリが流入する内槽５０ｂを有しており、この内槽５０ｂの上方には無機中性凝集剤を投入する凝集剤投入部５１が設置されている。また、底泥スラリと無機中性凝集剤とを混合攪拌する攪拌装置５２が設置されている。そして、凝集分離槽５０の下部は略円錐形のホッパ部５０ａとなっており、このホッパ部５０ａの先側には濃縮槽６０と繋がる配管５ｂが接続している。また、凝集分離槽５０の上部には凝集分離槽５０の上澄み水を貯水池に放流する水配管７ａが接続している。 The coagulation/separation tank 50 has an inner tank 50b into which the bottom mud slurry separated by the iron particle centrifugal separation unit 76 flows, and above the inner tank 50b, an inorganic neutral coagulant is added. An input unit 51 is installed. Further, a stirring device 52 for mixing and stirring the bottom mud slurry and the inorganic neutral coagulant is installed. The lower part of the flocculation/separation tank 50 is a substantially conical hopper portion 50a, and a pipe 5b connected to the concentration tank 60 is connected to the tip side of the hopper portion 50a. Further, a water pipe 7a for discharging the supernatant water of the coagulation/separation tank 50 to a reservoir is connected to the upper part of the coagulation/separation tank 50.

また、濃縮槽６０は、凝集分離槽５０で凝集沈降した凝集底泥を静置してさらに濃縮する機能を有し、上部に凝集分離槽５０と繋がった配管５ｂが接続している。また、濃縮槽６０の下部は略円錐形のホッパ部６０ａとなっており、このホッパ部６０ａの先側には濃縮槽６０で濃縮された濃縮底泥を脱水部８０に送る配管５ｃが接続している。また、濃縮槽６０の上部には濃縮槽６０の上澄み水を貯水池に放流する水配管７ｂが接続している。 Further, the concentrating tank 60 has a function of allowing the flocculated bottom mud coagulated and settled in the flocculation/separation tank 50 to stand still and further concentrating it, and a pipe 5b connected to the flocculation/separation tank 50 is connected to an upper portion thereof. The lower part of the concentration tank 60 is a hopper portion 60a having a substantially conical shape, and a pipe 5c for sending the concentrated bottom mud concentrated in the concentration tank 60 to the dehydration portion 80 is connected to the tip side of the hopper portion 60a. ing. Further, a water pipe 7b for discharging the supernatant water of the concentration tank 60 to the reservoir is connected to the upper portion of the concentration tank 60.

尚、分離処理装置９０は凝集分離槽５０、濃縮槽６０の上澄み水を一旦貯水して適宜貯水池に放流する水循環槽を有しても良い。この構成によれば、水循環槽に貯水した上澄み水を設備の洗浄等に利用することができる。これにより、水道栓が分離処理装置９０の近傍に存在しない場合でも、設備の洗浄等の作業を円滑に行うことができる。また、洗浄に関する水道費用を削減することができる。 The separation treatment device 90 may have a water circulation tank for temporarily storing the supernatant water of the flocculation/separation tank 50 and the concentration tank 60 and appropriately discharging it to a reservoir. According to this configuration, the supernatant water stored in the water circulation tank can be used for cleaning the equipment. Thereby, even if the tap is not present in the vicinity of the separation processing device 90, the work such as cleaning of the equipment can be smoothly performed. In addition, the water supply cost for cleaning can be reduced.

次に、本発明に係る浚渫システム１００に好適な脱水部８０の構成を図４を用いて説明する。本発明に好適な脱水部８０は、布製でベルト状の濾布８２と、スラリ（濃縮底泥）を濾布８２上に堆積させるスラリーダム部８１と、濾布８２上のスラリの過剰な水分を吸引する吸引部８３と、大ローラ８６ａと複数の小ローラ８６ｂとを有し、この大ローラ８６ａと小ローラ８６ｂとの間隙を通過することで濾布８２上のスラリを圧接し脱水するベルトプレス部８６と、脱水した底泥を濾布８２上から剥離するスクレイパ８７と、を有している。そして、濾布８２を送る搬送ローラ８４が回転することで、濾布８２はスラリーダム部８１と吸引部８３とベルトプレス部８６とを略一定の速度で連続的に移動する。 Next, the configuration of the dewatering unit 80 suitable for the dredging system 100 according to the present invention will be described with reference to FIG. The dewatering section 80 suitable for the present invention includes a cloth belt-shaped filter cloth 82, a slurry dam section 81 for depositing slurry (concentrated bottom mud) on the filter cloth 82, and an excessive water content of the slurry on the filter cloth 82. A belt that has a suction portion 83 for sucking the water, a large roller 86a, and a plurality of small rollers 86b, and passes through the gap between the large roller 86a and the small rollers 86b to press the slurry on the filter cloth 82 and dewater it. It has a press part 86 and a scraper 87 for separating the dehydrated bottom mud from the filter cloth 82. Then, as the transport roller 84 that sends the filter cloth 82 rotates, the filter cloth 82 continuously moves at the slurry dam portion 81, the suction portion 83, and the belt press portion 86 at a substantially constant speed.

次に、本発明に係る浚渫システム１００の動作を説明する。先ず、分離処理装置９０を浚渫を行う貯水池近傍の陸地に設置する。また、台船１０を浚渫を行う貯水池に浮かべる。この台船１０には送水ホース１２で繋がった送水ポンプ２０が設置されている。 Next, the operation of the dredging system 100 according to the present invention will be described. First, the separation treatment device 90 is installed on the land near the reservoir for dredging. Also, the pontoon 10 is floated on a reservoir for dredging. A water supply pump 20 connected to the water supply hose 12 is installed on the berth 10.

次に、台船１０に作業者が搭乗し、台船１０を浚渫場所に移動させる。そして、竿等の測量器具を用いて浚渫場所の大まかな水深と底泥の厚みを把握する。次に、作業者は昇降機１６を操作して送水ポンプ２０を貯水池中に投入する。次に、作業者は分離処理装置９０側の作業者に対し、送水ポンプ２０の稼働を要求する。分離処理装置９０側の作業者はこの要求を受けて、送水ポンプ制御盤を操作し送水ポンプ２０を稼働する。これにより、ポンプ本体部２１内のモータが回転し、インペラ２３と攪拌羽根２６とが回転動作する。そして、貯水池の水はケーシング２２の取水口から吸引され送水ホース１２を介して分離処理装置９０に圧送される。 Next, an operator boards the boat 10 and moves the boat 10 to the dredging site. Then, using a surveying instrument such as a rod, grasp the rough water depth at the dredging site and the thickness of the bottom mud. Next, the operator operates the elevator 16 to put the water pump 20 into the reservoir. Next, the worker requests the worker on the separation processing device 90 side to operate the water pump 20. In response to this request, the worker on the side of the separation processing device 90 operates the water pump control panel to operate the water pump 20. As a result, the motor in the pump body 21 rotates, and the impeller 23 and the stirring blade 26 rotate. Then, the water in the reservoir is sucked from the intake port of the casing 22 and pressure-fed to the separation treatment device 90 via the water-feeding hose 12.

次に、台船１０側の作業者は昇降機１６を操作して送水ポンプ２０を貯水池中の適切な位置に保持する。この適切な位置とは、送水ポンプ２０の吸引する底泥スラリの濃度が５％〜１０％となる位置である。尚、底泥スラリの濃度は分離処理装置９０側の作業者が目視等で確認し、適宜、台船１０側の作業者に連絡して調整する。 Next, the operator on the side of the pontoon 10 operates the elevator 16 to hold the water pump 20 at an appropriate position in the reservoir. The appropriate position is a position where the concentration of the bottom mud slurry sucked by the water pump 20 is 5% to 10%. The concentration of the bottom mud slurry is visually checked by the operator on the separation treatment device 90 side, and appropriately contacted with the operator on the berth 10 side to adjust the concentration.

送水ポンプ２０が底泥の表層近傍の適切な位置に保持されると、攪拌羽根２６が底泥を攪拌するとともに、攪拌羽根２６の回転動作によって発生する下向きの水流が底泥を舞い上げる。舞い上げられた底泥はインペラ２３の回転動作により貯水池の水ごとケーシング２２の取水口から吸引され、底泥スラリとして送水ホース１２を介して分離処理装置９０に圧送される。このとき、底泥中に混在する落ち葉、枯枝、水生植物の葉茎根、ビニール等のゴミ類は、ケーシング２２の取水口に設置されたカッタ２４と回転するインペラ２３及び攪拌羽根２６との間で適度な大きさに破砕される。これにより、これらゴミ類の送水ポンプ２０への絡まりや、ケーシング２２内や送水ホース１２内における目詰りを防止することができる。また、攪拌羽根２６は空き缶等の比較的大型で硬質な夾雑物を跳ね飛ばして、これら夾雑物が送水ポンプ２０で吸引されることを防止する。尚、底泥が厚い場合には、表層近傍の底泥を浚渫した後、徐々に送水ポンプ２０を降下させ底泥を掘り下げるようにして浚渫して行くことが好ましい。 When the water supply pump 20 is held at an appropriate position near the surface layer of the bottom mud, the stirring blade 26 stirs the bottom mud, and the downward water flow generated by the rotating operation of the stirring blade 26 soars the bottom mud. The floated bottom mud is sucked together with the water in the reservoir from the intake port of the casing 22 by the rotating operation of the impeller 23, and is pressure-fed to the separation treatment device 90 as the bottom mud slurry via the water supply hose 12. At this time, debris such as fallen leaves, dead branches, foliage roots of aquatic plants, and vinyl mixed in the bottom mud are generated by the cutter 24 installed at the intake of the casing 22, the rotating impeller 23, and the stirring blade 26. It is crushed to an appropriate size in between. As a result, it is possible to prevent entanglement of these dusts with the water supply pump 20 and clogging of the casing 22 and the water supply hose 12. Further, the stirring blade 26 bounces off relatively large and hard contaminants such as empty cans, and prevents these contaminants from being sucked by the water pump 20. When the bottom mud is thick, it is preferable to dredge the bottom mud in the vicinity of the surface layer and then gradually lower the water pump 20 to dig down the bottom mud for dredging.

送水ポンプ２０によって吸引、圧送された底泥スラリは送水ホース１２を通って遠心分離部３０の外筒３２ａに横方向を向けて吐出される。そして、吐出された底泥スラリは外筒３２ａ内を渦を巻いて流下する。このとき、砂や小石等の比較的重い重量物は遠心分離部３０の外筒３２ａに沿って下方へ落下し、遠心分離部３０のホッパ部３４に堆積する。また、その他の底泥スラリは内筒３２ｂの下端から内筒３２ｂ内を通って夾雑物選別部４０側へ搬送される。尚、ホッパ部３４に堆積した重量物は開閉コック３６ａを適宜開閉することで排出口３６から排出され、廃棄や選別等のしかるべき処理が行われる。 The bottom mud slurry sucked and pressure-fed by the water pump 20 is discharged laterally to the outer cylinder 32a of the centrifugal separator 30 through the water hose 12. Then, the discharged bottom mud slurry swirls and flows down in the outer cylinder 32a. At this time, relatively heavy heavy objects such as sand and pebbles fall downward along the outer cylinder 32a of the centrifugal separator 30 and accumulate on the hopper 34 of the centrifugal separator 30. Further, the other bottom mud slurry is conveyed from the lower end of the inner cylinder 32b through the inner cylinder 32b to the contaminant sorting section 40 side. The heavy load accumulated on the hopper unit 34 is discharged from the discharge port 36 by appropriately opening and closing the opening/closing cock 36a, and appropriate processing such as disposal and selection is performed.

また、遠心分離部３０を通過した底泥スラリは配管５ａを介して夾雑物選別部４０の流量測定升４４に吐出され、分離処理装置９０側の作業者はこの流量測定升４４によって底泥スラリの流量を把握する。そして、送水ポンプ制御盤を操作して底泥スラリが適正な流量となるように送水ポンプ２０の回転数を調整する。また、底泥スラリの濃度を目視等で確認し、濃度が適正でない場合、台船１０側の作業者に指示して送水ポンプ２０の位置調整を行わせる。 Further, the bottom mud slurry that has passed through the centrifugal separation unit 30 is discharged to the flow rate measuring box 44 of the foreign matter sorting section 40 via the pipe 5 a, and the worker on the separation processing device 90 side uses the bottom flow mud slurry 44. Understand the flow rate of. Then, the water supply pump control panel is operated to adjust the rotation speed of the water supply pump 20 so that the bottom mud slurry has an appropriate flow rate. Further, the concentration of the bottom mud slurry is visually confirmed, and if the concentration is not appropriate, the operator on the side of the ship 10 is instructed to adjust the position of the water pump 20.

流量測定升４４を通った底泥スラリは、夾雑物選別部４０の夾雑物選別装置４２に吐出される。そして、この夾雑物選別装置４２において、底泥スラリ中に混入した夾雑物、即ち、カッタ２４で破砕されたゴミ類等が選別除去される。尚、本例では夾雑物選別装置４２としてベルトスクリーンを用いた例を図示しており、選別された夾雑物はベルトスクリーンの移動によって自動的に排出される。排出された夾雑物は例えばスライダ４６上を滑り落ちて、夾雑物集積用袋等に落下し、廃棄等のしかるべき処理に付される。 The bottom mud slurry that has passed through the flow rate measuring unit 44 is discharged to the foreign matter sorting device 42 of the foreign matter sorting unit 40. Then, in the foreign matter sorting device 42, foreign matters mixed in the bottom mud slurry, that is, dust and the like crushed by the cutter 24 are selectively removed. In this example, a belt screen is used as the contaminant sorting device 42, and the sorted contaminants are automatically discharged by the movement of the belt screen. The discharged contaminants slide down on the slider 46, fall into a contaminant collecting bag or the like, and are subjected to appropriate treatment such as disposal.

夾雑物選別部４０で夾雑物が除去された底泥スラリは、鉄粒混合部７０の鉄粒添加槽７２ａに吐出される。また、鉄粒添加槽７２ａには新品もしくは鉄粒遠心分離部７６で分離した多孔質鉄粒が投入され、攪拌装置５２によって混合攪拌される。また、鉄粒添加槽７２ａには鉄粒混合槽７２ｂが接続しており、多孔質鉄粒が混合した底泥スラリは各槽の攪拌装置５２によって攪拌されながら、下流の鉄粒混合槽７２ｂ側に順次移動する。そして、底泥スラリ中に溶出している重金属成分は、これら鉄粒添加槽７２ａ、鉄粒混合槽７２ｂ内において、スラリ中に混合した多孔質鉄粒の微細孔によって吸着捕集される。尚、鉄粒混合部７０における底泥スラリの停留時間は前述のように鉄粒混合槽７２ｂの連結数によって最適化され、最下流の鉄粒混合槽７２ｂにおいては溶出している重金属成分がほぼ多孔質鉄粒によって吸着捕集され所定の濃度以下となる。 The bottom mud slurry from which the contaminants have been removed by the contaminant selection unit 40 is discharged to the iron particle addition tank 72a of the iron particle mixing unit 70. In addition, new iron particles or porous iron particles separated by the iron particle centrifugal separation unit 76 are charged into the iron particle addition tank 72a, and mixed and stirred by the stirring device 52. Further, an iron particle mixing tank 72b is connected to the iron particle adding tank 72a, and the bottom mud slurry in which the porous iron particles are mixed is stirred by the stirring device 52 of each tank while the iron particle mixing tank 72b is provided on the downstream side. Move to. Then, the heavy metal components eluted in the bottom mud slurry are adsorbed and collected by the fine pores of the porous iron particles mixed in the slurry in the iron particle addition tank 72a and the iron particle mixing tank 72b. The staying time of the bottom mud slurry in the iron particle mixing section 70 is optimized by the number of connected iron particle mixing tanks 72b as described above, and the heavy metal components eluted in the most downstream iron particle mixing tank 72b are almost the same. It is adsorbed and collected by the porous iron particles and has a predetermined concentration or less.

また、第２送水ポンプ７４は最下流の鉄粒混合槽７２ｂの底泥スラリを多孔質鉄粒ごと吸引し、送水ホース１２ａを通して鉄粒遠心分離部７６の外筒３２ａに横方向を向けて吐出する。吐出した底泥スラリは外筒３２ａ内を渦を巻いて流下する。このとき、比重の重い多孔質鉄粒は鉄粒遠心分離部７６の外筒３２ａに沿って下方へ落下し、ホッパ部３４に堆積する。また、底泥スラリは内筒３２ｂの下端から内筒３２ｂ内を通って凝集分離槽５０側へ搬送される。尚、ホッパ部３４に堆積した多孔質鉄粒は開閉コック３６ａを適宜開閉することで排出口３６から鉄粒添加槽７２ａ内に排出され再利用される。また、所定回数もしくは所定水量の処理に用いられた多孔質鉄粒は鉄粒回収部７８へと排出され、吸着した重金属成分ごと然るべき方法により処分される。これにより、底泥スラリ中に溶出している重金属成分は除去される。ただし、固体の重金属成分は底泥とともに凝集分離槽５０側へと排出される。 In addition, the second water pump 74 sucks the bottom mud slurry of the iron granule mixing tank 72b at the most downstream side together with the porous iron granules, and horizontally discharges it through the water supply hose 12a to the outer cylinder 32a of the iron particle centrifugal separator 76. To do. The discharged bottom mud slurry swirls and flows down in the outer cylinder 32a. At this time, the porous iron particles having a high specific gravity drop downward along the outer cylinder 32a of the iron particle centrifugal separation unit 76 and are deposited on the hopper unit 34. Further, the bottom mud slurry is conveyed from the lower end of the inner cylinder 32b to the coagulation/separation tank 50 side through the inner cylinder 32b. The porous iron particles accumulated in the hopper portion 34 are discharged from the discharge port 36 into the iron particle adding tank 72a by reopening and closing the opening/closing cock 36a, and are reused. Further, the porous iron particles used for the treatment of the predetermined number of times or the predetermined amount of water are discharged to the iron grain recovery section 78, and the adsorbed heavy metal components are disposed by an appropriate method. As a result, heavy metal components eluted in the bottom mud slurry are removed. However, the solid heavy metal component is discharged to the coagulation/separation tank 50 side together with the bottom mud.

次に、鉄粒遠心分離部７６で多孔質鉄粒と分離した底泥スラリは凝集分離槽５０の内槽５０ｂに吐出される。また、この内槽５０ｂには凝集剤投入部５１から無機中性凝集剤が投入され攪拌装置５２によって吐出された底泥スラリと混合攪拌される。ここで投入する無機中性凝集剤としては、脱水後の凝集物からの重金属成分の溶出を抑制するものを用いる。具体的には、石膏を主成分とした無機中性凝集剤を用い、さらに具体的にはアルミナ・ケイ酸塩を主体とする天然鉱物３０〜５０重量％と硫酸カルシウム４５〜６５重量％と有機系凝集剤１〜５重量％とから成る主成分１００重量部に対し、硫酸アルミニウム３０〜５０重量部、塩化アルミニウム５〜１０重量部、およびアルカリ金属炭酸塩２０〜４０重量部が配合された無機中性凝集剤を用いることが特に好ましい。 Next, the bottom mud slurry separated from the porous iron particles by the iron particle centrifugal separation unit 76 is discharged to the inner tank 50b of the coagulation separation tank 50. In addition, the inorganic neutral coagulant is charged into the inner tank 50b from the coagulant charging section 51 and mixed and stirred with the bottom mud slurry discharged by the stirring device 52. As the inorganic neutral coagulant to be added here, one that suppresses elution of heavy metal components from the aggregate after dehydration is used. Specifically, we have use principal component and the inorganic neutral coagulant gypsum, and more specifically a natural mineral 30-50% by weight and 45 to 65% by weight of calcium sulphate which is mainly of alumina-silicate 30 to 50 parts by weight of aluminum sulfate, 5 to 10 parts by weight of aluminum chloride, and 20 to 40 parts by weight of alkali metal carbonate were blended with 100 parts by weight of a main component composed of 1 to 5% by weight of an organic flocculant. It is particularly preferable to use an inorganic neutral coagulant.

そして、この無機中性凝集剤の添加により、底泥スラリ中の泥、ヘドロ等の底泥は固体の重金属成分とともに凝集し下方のホッパ部５０ａに沈殿する。そして、沈殿した凝集底泥は凝集分離槽５０への新たな底泥スラリの流入によりホッパ部５０ａに接続された配管５ｂに押し出され、この配管５ｂを通って濃縮槽６０の上部に吐出する。また、凝集分離槽５０の上澄み水は水配管７ａを通して貯水池に放流される。尚、本発明に用いる無機中性凝集剤は石膏を主成分としており、水のｐＨを変化させたり、動植物に悪影響を与える成分を含有していない。また、この上澄み水は鉄粒混合部７０によって水中に溶出した重金属成分が捕集済みであるから、分離した上澄み水をそのまま貯水池に放流することができる。 Then, by adding the inorganic neutral coagulant, the mud in the bottom mud slurry, sludge and other bottom mud coagulate together with the solid heavy metal component and precipitate in the lower hopper section 50a. Then, the settled flocculated bottom mud is pushed out to the pipe 5b connected to the hopper 50a by the inflow of new bottom mud slurry to the flocculation/separation tank 50, and is discharged to the upper part of the concentration tank 60 through the pipe 5b. Also, the supernatant water of the coagulation/separation tank 50 is discharged to the reservoir through the water pipe 7a. The inorganic neutral flocculant used in the present invention contains gypsum as a main component, and does not contain components that change the pH of water or adversely affect plants and animals. Moreover, since the heavy metal component eluted into the water by the iron particle mixing section 70 has been collected in the supernatant water, the separated supernatant water can be discharged as it is to the reservoir.

濃縮槽６０に吐出された凝集底泥は、この濃縮槽６０で静置され濃縮槽６０の下方のホッパ部６０ａに沈降してさらに濃縮される。そして、この濃縮底泥は、濃縮槽６０への新たな凝集底泥の流入によりホッパ部６０ａに接続された配管５ｃに押し出され、この配管５ｃを通って脱水部８０に搬送される。また、濃縮槽６０の上澄み水は水配管７ｂを通して貯水池に放流される。 The flocculated bottom mud discharged to the concentration tank 60 is allowed to stand still in the concentration tank 60, settles in the hopper portion 60a below the concentration tank 60, and is further concentrated. Then, this concentrated bottom mud is pushed out to the pipe 5c connected to the hopper portion 60a by the inflow of new agglomerated bottom mud to the concentration tank 60, and is conveyed to the dehydration unit 80 through this pipe 5c. Further, the supernatant water of the concentration tank 60 is discharged to the reservoir through the water pipe 7b.

また、配管５ｃから吐出された濃縮底泥は脱水部８０のスラリーダム部８１に溜まり、この状態で濾布８２が一定速度で移動することで濾布８２上にほぼ一定の厚みで堆積する。濾布８２上に堆積した濃縮底泥は吸引部８３に搬送され、この吸引部８３によって濾布８２の裏面側から過剰な水分が吸引除去される。吸引された水分は排水部８９を介して貯水池に放流される。次に、濾布８２はベルトプレス部８６に搬送される。ベルトプレス部８６は大ローラ８６ａと複数の小ローラ８６ｂとで構成される脱水ローラを有し、大ローラ８６ａが濃縮底泥側に位置し、小ローラ８６ｂが濾布８２の裏面側に位置する。そして、濃縮底泥は濾布８２ごと脱水ローラ８６ａ、８６ｂ間を通され、この脱水ローラ８６ａ、８６ｂの圧接によって脱水される。脱水された水分は排水部８９を介して貯水池に放流される。そして、この脱水部８０の脱水により、濃縮底泥は含水率が５０％〜５５％程度の脱水底泥となる。この脱水底泥はスクレイパ８７によって剥ぎ取られ、脱水底泥回収袋１等に送られて回収される。 Further, the concentrated bottom mud discharged from the pipe 5c collects in the slurry dam portion 81 of the dehydration section 80, and in this state, the filter cloth 82 moves at a constant speed and is deposited on the filter cloth 82 with a substantially constant thickness. The concentrated bottom mud accumulated on the filter cloth 82 is conveyed to the suction section 83, and the suction section 83 sucks and removes excess water from the back surface side of the filter cloth 82. The sucked water is discharged to the reservoir via the drainage unit 89. Next, the filter cloth 82 is conveyed to the belt press unit 86. The belt press unit 86 has a dewatering roller composed of a large roller 86a and a plurality of small rollers 86b, the large roller 86a is located on the concentrated bottom mud side, and the small roller 86b is located on the back surface side of the filter cloth 82. .. Then, the concentrated bottom mud is passed between the dewatering rollers 86a and 86b together with the filter cloth 82, and dewatered by the pressure contact between the dewatering rollers 86a and 86b. The dehydrated water is discharged to the reservoir via the drainage unit 89. Then, by the dehydration of the dehydration section 80, the concentrated bottom mud becomes a dehydrated bottom mud having a water content of about 50% to 55%. The dewatered bottom mud is stripped off by the scraper 87 and sent to the dewatered bottom mud collection bag 1 or the like to be collected.

尚、本発明に係る浚渫システム１００は、基本的に貯水池から鉄粒混合部７０までの底泥スラリの搬送を送水ポンプ２０の圧送と自然流下で行い、また鉄粒混合部７０から凝集分離槽５０、濃縮槽６０、脱水部８０までの底泥スラリ等（底泥及び上澄み水）の搬送を第２送水ポンプ７４の圧送と自然流下で行う。そして、特に凝集分離槽５０、濃縮槽６０、脱水部８０間の底泥の移動を自然流下によって行う事で凝集底泥、濃縮底泥が再分散されることがなく、濃縮底泥を高濃度のまま脱水部８０に搬送することができる。 The dredging system 100 according to the present invention basically transports the bottom mud slurry from the reservoir to the iron particle mixing section 70 by pressure feeding of the water pump 20 and gravity flow, and also from the iron particle mixing section 70 to the coagulation separation tank. The transportation of the bottom mud slurry and the like (bottom mud and supernatant water) to 50, the concentration tank 60, and the dewatering section 80 is carried out by pressure feeding of the second water pump 74 and natural flow. Further, by moving the bottom mud among the flocculation/separation tank 50, the concentration tank 60, and the dehydration section 80 by gravity flow, the flocculated bottom mud and the concentrated bottom mud are not redispersed, and the concentrated bottom mud has a high concentration. It can be conveyed to the dehydration section 80 as it is.

ここで、図５の表に、未処理の底泥スラリの上澄み液、多孔質鉄粒処理のみの底泥スラリの上澄み液、無機中性凝集剤処理のみの上澄み液、多孔質鉄粒＋無機中性凝集剤処理後の上澄み液の各液中のヒ素濃度及びｐＨを示す。また、各試料の脱水底泥を水中に浸漬した時のヒ素の溶出試験の結果（濃度）を示す。尚、試料Ａ−１〜Ａ−４と試料Ｂ−１〜Ｂ−４とは底泥スラリの取得日が異なるものである。また、多孔質鉄粒の添加量は底泥スラリ１Ｌ当たり２０ｇとした。図５から、未処理の底泥スラリの試料Ａ−１、Ｂ−１の上澄み液のヒ素濃度は、それぞれ０．０１６ｍｇ／Ｌ、０．０３８ｍｇ／Ｌであったのに対し、多孔質鉄粒による吸着処理を行った試料Ａ−２〜Ａ−４、Ｂ−３、Ｂ−４のヒ素濃度はいずれも０．００６ｍｇ／Ｌ〜０．００３ｍｇ／Ｌであり、土壌汚染防止法のヒ素濃度の基準値０．０１ｍｇ／Ｌよりも低い値を示した。よって、本願発明の多孔質鉄粒は溶出した重金属成分を効果的に捕集可能なことが判る。ただし、多孔質鉄粒処理のみの試料Ａ−２の溶出試験結果は０．０１２ｍｇ／Ｌと未処理の底泥スラリ試料Ａ−１と同等の値であり、多孔質鉄粒では底泥中の重金属成分は捕集できないことが判る。また、無機中性凝集剤処理のみの試料Ｂ−２は上澄み液のヒ素濃度が０．０３４ｍｇ／Ｌと未処理の底泥スラリの試料Ｂ−１と同等の値であり、無機中性凝集剤のみではスラリ中に溶出している重金属成分の捕集はできないことが判る。 Here, in the table of FIG. 5, the supernatant liquid of untreated bottom mud slurry, the supernatant liquid of bottom mud slurry only treated with porous iron particles, the supernatant liquid only treated with inorganic neutral coagulant, the porous iron particles+inorganic The arsenic concentration and pH in each liquid of the supernatant after the treatment with the neutral coagulant are shown. The results (concentration) of the arsenic elution test when the dehydrated bottom mud of each sample is immersed in water are also shown. The samples A-1 to A-4 and the samples B-1 to B-4 have different acquisition dates of the bottom mud slurry. The amount of porous iron particles added was 20 g per 1 L of the bottom mud slurry. From FIG. 5, the arsenic concentrations of the supernatants of Samples A-1 and B-1 of the untreated bottom mud slurry were 0.016 mg/L and 0.038 mg/L, respectively, while the porous iron particles Samples A-2 to A-4, B-3, and B-4 that had been subjected to the adsorption treatment according to Example 1 all had an arsenic concentration of 0.006 mg/L to 0.003 mg/L. The value was lower than the standard value of 0.01 mg/L. Therefore, it is understood that the porous iron particles of the present invention can effectively collect the eluted heavy metal component. However, the elution test result of the sample A-2 only treated with the porous iron particles was 0.012 mg/L, which was a value equivalent to that of the untreated bottom mud slurry sample A-1. It turns out that heavy metal components cannot be collected. Sample B-2, which was treated with inorganic neutral coagulant only, had an arsenic concentration of the supernatant of 0.034 mg/L, which was equivalent to that of sample B-1 of untreated bottom mud slurry. It can be seen that the heavy metal component eluted in the slurry cannot be collected only by itself.

また、無機中性凝集剤処理を行っていない未処理の底泥スラリの試料Ａ−１、Ｂ−１及び多孔質鉄粒処理のみの試料Ａ−２の脱水底泥の溶出試験におけるヒ素濃度は、それぞれ０．０１２ｍｇ／Ｌ、０．０１４ｍｇ／Ｌ、０．０１２ｍｇ／Ｌであったのに対し、本願発明の無機中性凝集剤によって凝集した脱水底泥の試料Ａ−３、Ａ−４、Ｂ−３、Ｂ−４の溶出試験のヒ素濃度は、無機中性凝集剤の添加量が底泥の乾燥重量に対して０．９５ｗｔ％の試料Ａ−３のものが０．００６ｍｇ／Ｌを示したものの、添加量１．５ｗｔ％〜３．０ｗｔ％のものは測定下限値未満でありいずれも基準値０．０１ｍｇ／Ｌよりも低い値を示した。これらのことから、本願発明の無機中性凝集剤を用いることで底泥中の重金属成分は底泥とともに固定不溶化され、外部への溶出が防止されることが判る。尚、無機中性凝集剤処理のみの試料Ｂ−２は溶出試験のヒ素濃度が０．００７ｍｇ／Ｌと比較的高い値を示したが、これはスラリ中の溶出ヒ素を除去していないためである。 In addition, the arsenic concentration in the elution test of the dehydrated bottom mud of Samples A-1 and B-1 of untreated bottom mud slurry not treated with inorganic neutral coagulant and Sample A-2 only treated with porous iron particles was , 0.012 mg/L, 0.014 mg/L, and 0.012 mg/L, respectively, whereas samples A-3, A-4 of the dehydrated bottom mud aggregated by the inorganic neutral flocculant of the present invention, The arsenic concentration in the dissolution test of B-3 and B-4 was 0.006 mg/L for the sample A-3 in which the addition amount of the inorganic neutral coagulant was 0.95 wt% with respect to the dry weight of the bottom mud. Although shown, the amount of addition of 1.5 wt% to 3.0 wt% was less than the lower limit of measurement, and all showed values lower than the reference value of 0.01 mg/L. From these, it is understood that the use of the inorganic neutral flocculant of the present invention causes the heavy metal components in the bottom mud to be fixed and insolubilized together with the bottom mud, and to prevent elution to the outside. Sample B-2, which was only treated with the inorganic neutral coagulant, had a relatively high arsenic concentration of 0.007 mg/L in the dissolution test, but this is because the dissolved arsenic in the slurry was not removed. is there.

尚、ｐＨに関しては、試料Ａ−２〜Ａ−４、試料Ｂ−１〜Ｂ−４間で大きな変化は無く、本願発明の無機中性凝集剤は水質（ｐＨ）に大きな影響を与えないことが判る。 Regarding pH, there is no great change between Samples A-2 to A-4 and Samples B-1 to B-4, and the inorganic neutral coagulant of the present invention does not significantly affect water quality (pH). I understand.

以上のように、本願発明の浚渫システム１００は、水中に溶出している重金属成分は多孔質鉄粒が捕集除去して環境基準値以下にするとともに底泥中の重金属成分は無機中性凝集剤が固定不溶化し外部への溶出を防止する。また、本願発明が使用する無機中性凝集剤は添加の前後で水質を大きく変化させず、また動植物に有害な成分を含有しない。よって、本願発明の浚渫システム１００により分離した上澄み水は浚渫した貯水池にそのまま放流することが可能であり、貯水池の機能を維持したまま浚渫作業を行うことができる。また、貯水池に生息する動植物の生態系を維持することができる。また、浚渫により生じた脱水底泥は重金属成分が溶出しないため植物栽培用の培養土として使用することができる。これにより、環境に対する負荷を軽減することができる。さらに、重金属成分を吸着した多孔質鉄粒の量は脱水底泥の量に比較して少ないため、処分コストの削減を図ることができる。 As described above, in the dredging system 100 of the present invention, the heavy metal components eluted in the water are collected and removed by the porous iron particles so as to be below the environmental standard value, and the heavy metal components in the bottom mud are inorganic neutral coagulation. The agent is fixed and insoluble to prevent elution to the outside. In addition, the inorganic neutral coagulant used in the present invention does not significantly change the water quality before and after addition, and does not contain a component harmful to plants and animals. Therefore, the supernatant water separated by the dredging system 100 of the present invention can be discharged as it is to the dredged reservoir, and the dredging work can be performed while maintaining the function of the reservoir. In addition, the ecosystem of plants and animals that inhabit the reservoir can be maintained. In addition, the dehydrated bottom mud produced by dredging can be used as a culture soil for plant cultivation because heavy metal components do not elute. This can reduce the load on the environment. Furthermore, since the amount of porous iron particles that have adsorbed heavy metal components is smaller than the amount of dehydrated bottom mud, it is possible to reduce the disposal cost.

またさらに、本発明に係る浚渫システム１００は、多孔質鉄粒の分離を遠心分離装置（鉄粒遠心分離部７６）のみで行う。これにより、多孔質鉄粒の分離を短時間で効率良く行う事が可能となり、底泥スラリに対する高い処理能力を有する。 Furthermore, in the dredging system 100 according to the present invention, the porous iron particles are separated only by the centrifugal separator (iron particle centrifugal separator 76). This makes it possible to efficiently separate the porous iron particles in a short time, and has a high treatment capacity for the bottom mud slurry.

またさらに、本発明に係る浚渫システム１００は［特許文献１］に記載の発明と同様、貯水池の遮水作業、排水作業が不要で、作業期間の短縮と低コスト化を図ることができる。また、分離処理装置９０を設置して底泥の処理を行うため、従来の重機を使用した浚渫と比較して、省スペースで浚渫作業を行うことができる。また、分離処理装置９０は分解して現地にて組立てが可能なため、大型の運搬車両が進入できない貯水池に対しても浚渫作業を行うことができる。 Furthermore, the dredging system 100 according to the present invention does not require the work of blocking water and draining the reservoir, as in the invention described in [Patent Document 1], and can shorten the working period and reduce the cost. In addition, since the separation treatment device 90 is installed to treat the bottom mud, it is possible to perform the dredging work in a smaller space as compared with the dredging using the conventional heavy equipment. Further, since the separation treatment device 90 can be disassembled and assembled at the site, it is possible to perform dredging work on a reservoir where a large transport vehicle cannot enter.

尚、本例で示した浚渫システム１００、分離処理装置９０、鉄粒混合部７０等の各部の形状、構成、動作機構、配管経路等は一例であり、本発明は本発明の要旨を逸脱しない範囲で変更して実施することが可能である。 It should be noted that the shapes, configurations, operating mechanisms, pipe paths, etc. of the respective parts such as the dredging system 100, the separation treatment device 90, the iron particle mixing part 70 and the like shown in this example are examples, and the present invention does not depart from the gist of the present invention. The range can be changed and implemented.

２０送水ポンプ
３０遠心分離部（スラリ分離部）
４０夾雑物選別部（スラリ分離部）
５０凝集分離槽
７０鉄粒混合部
７２ａ鉄粒添加槽
７２ｂ鉄粒混合槽
７４第２送水ポンプ
７６鉄粒遠心分離部
８０脱水部
１００浚渫システム 20 water pump
30 Centrifuge (slurry separator)
40 Foreign matter sorting section (slurry separating section)
50 Coagulation separation tank
70 Iron grain mixing section
72a Iron grain addition tank
72b Iron grain mixing tank
74 Second water pump
76 Iron Grain Centrifuge
80 Dehydrator
100 dredging system

Claims

A water pump that sucks bottom mud together with water and pumps it as bottom mud slurry,
A coagulation separation tank for coagulating and sedimenting the bottom mud by adding a coagulant to the bottom mud slurry,
In a dredging system having a dehydration section for dehydrating the bottom mud coagulated and settled by the coagulant,
A slurry separation unit that includes a cyclone-type centrifugal separator and removes heavy substances and contaminants from the bottom mud slurry that is pressure-fed by the water pump,
Specific surface area sediment slurry passing through the slurry separation unit at 0.12m ^² /g~0.36m ² / g, apparent density ^{^{1.3g / cm 3 ~1.5g / cm 3}} , the cyclone Iron for adsorbing heavy metal components eluted in the bottom mud slurry to the porous iron particles by adding porous iron particles having a particle size of 0.1 mm to 1 mm that can be separated by a centrifuge and stirring the mixture A grain mixing section,
Iron particles for separating the porous iron particles together with heavy metal components by a single cyclone-type centrifugal separator similar to the centrifugal separator of the slurry separator, and delivering the separated bottom mud slurry to the flocculation/separation tank Further having a centrifugal separator,
The coagulant Ri inorganic neutral coagulant der the plaster does not change the pH of suppressing and water elution of heavy metal components of the solid bottom mud as a main component after coagulation,
Further, the iron particle mixing section has an iron particle addition tank for adding the porous iron particles to the bottom mud slurry, and an iron particle mixing tank for maintaining the porous iron particles and the bottom mud slurry while stirring. Then
The iron particle addition tank and the iron particle mixing tank are connected in series by a connecting pipe located below each tank, and the staying time of the bottom mud slurry is adjusted by the number of the iron particle mixing tanks connected. A dredging system that does.

The dredging system according to claim 1 , wherein the iron particle centrifugal separation unit is located above the iron particle addition tank and discharges the separated porous iron particles to the iron particle addition tank.

The bottom mud slurry from the slurry separation section to the iron particle mixing section is conveyed by pressure feed by a water pump and natural flow, and the bottom mud slurry from the iron particle mixing section to the dehydration section is conveyed to the iron particle centrifugal separation section. The dredging system according to claim 1 , wherein the dredging system is performed by pressure feeding by a second water feeding pump that conveys the slurry and natural flow.

As an inorganic neutral coagulant, 100 parts by weight of a main component composed of 30 to 50% by weight of a natural mineral mainly composed of alumina silicate, 45 to 65% by weight of calcium sulfate, and 1 to 5% by weight of an organic coagulant. On the other hand, 30 to 50 parts by weight of aluminum sulfate, 5 to 10 parts by weight of aluminum chloride, and 20 to 40 parts by weight of alkali metal carbonate are used in combination, and any one of claims 1 to 3 is used. Dredging system described in.