JP3325689B2 - Treatment method for metal-containing wastewater - Google Patents
Treatment method for metal-containing wastewaterInfo
- Publication number
- JP3325689B2 JP3325689B2 JP2492494A JP2492494A JP3325689B2 JP 3325689 B2 JP3325689 B2 JP 3325689B2 JP 2492494 A JP2492494 A JP 2492494A JP 2492494 A JP2492494 A JP 2492494A JP 3325689 B2 JP3325689 B2 JP 3325689B2
- Authority
- JP
- Japan
- Prior art keywords
- reaction tank
- sludge
- metal
- tank
- added
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Removal Of Specific Substances (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、製鉄所や鋼鈑処理場等
から排出される鉄等の重金属を溶存含有している排水の
処理方法に関し、更に詳しくは各種の溶存重金属の分離
が極めて効率的であり、且つ生成するスラッジの含水率
が低く、スラッジの処理が容易である金属含有排水の処
理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating wastewater containing heavy metals such as iron discharged from steel mills and steel plate processing plants, and more particularly, to separation of various dissolved heavy metals. The present invention relates to a method for treating metal-containing wastewater, which is efficient, has a low water content of generated sludge, and is easy to treat sludge.
【０００２】[0002]
【従来の技術】従来、製鉄所や鋼鈑処理場等の如く鉄を
大量に処理する際には、大量の冷却水、表面処理水等が
発生し、これらの排水中には多量の第一鉄及び第二鉄の
他に、亜鉛、カドミウム、錫、ニッケル、アルミニウ
ム、銅等が含有されており、排水の放出或は再使用に際
しては、これらの溶存金属を充分に除去することが要求
されている。上記溶存金属の従来の除去方法としては、
金属含有排水を反応槽に導き、沈澱槽で沈降分離したス
ラッジの一部をアルカリ剤を加えてアルカリスラッジと
し、該アルカリスラッジを上記反応槽に導き、ｐＨをア
ルカリ性に調整して、溶存金属を水酸化物として析出さ
せ、該析出した水酸化物を凝集剤で凝集させ、凝集フロ
ックを沈澱槽で沈降分離する方法が行われている。2. Description of the Related Art Conventionally, when treating a large amount of iron such as in a steel mill or a steel plate processing plant, a large amount of cooling water and surface treatment water are generated. It contains zinc, cadmium, tin, nickel, aluminum, copper, etc. in addition to iron and ferric iron, and it is required to sufficiently remove these dissolved metals when discharging or reusing wastewater. ing. Conventional methods for removing the above dissolved metals include:
The metal-containing wastewater is led to the reaction tank, and a part of the sludge settled and separated in the settling tank is added with an alkali agent to form an alkali sludge.The alkali sludge is led to the reaction tank, the pH is adjusted to alkaline, and the dissolved metal is removed. A method of precipitating as hydroxide, aggregating the precipitated hydroxide with a coagulant, and segregating and separating agglomerated floc in a sedimentation tank is used.
【０００３】[0003]
【発明が解決しようとしている問題点】上記従来の沈澱
槽で沈降分離したスラッジを循環返送し、アルカリ剤を
添加したアルカリスラッジとして排水中の金属類を水酸
化物として沈澱折出させる処理方法において、第二鉄
（Ｆｅ3+）イオンの他に他の金属イオン、例えば、第一
鉄、亜鉛、カドミウム、錫、ニッケル、アルミニウム、
銅等を含有する排水を一括処理すると、第二鉄（Ｆ
ｅ3+）イオンと他の金属イオンとが折出沈澱するｐＨ領
域が異なる為に、第二鉄（Ｆｅ3+）イオンから生成する
水酸化物は結晶性の緻密な粒子とはならず、微細粒子と
して分散して折出沈澱する。この為、得られるスラッジ
は沈降性、濃縮性及び脱水性が低下し、又、析出した水
酸化物は、上澄水中に分散し沈澱槽から越流してしま
い、満足し得る処理水水質が得られないという問題があ
る。従って本発明の目的は、第二鉄の他に、種々の金属
を含有する金属含有排水中の金属の分離が極めて効率的
であり、且つ生成するスラッジの含水率が低くスラッジ
の処理が容易である金属含有排水の処理方法を提供する
ことである。SUMMARY OF THE INVENTION In the above-mentioned conventional processing method, sludge settled and separated in a sedimentation tank is circulated and returned, and metals in wastewater are precipitated as hydroxides as alkali sludge to which an alkali agent is added. , Ferric (Fe 3+ ) ions and other metal ions such as ferrous, zinc, cadmium, tin, nickel, aluminum,
When wastewater containing copper etc. is treated collectively, ferric iron (F
Since the pH region in which e 3+ ) ions and other metal ions precipitate and precipitate are different, the hydroxide formed from ferric (Fe 3+ ) ions does not become crystalline and dense particles, Disperses as fine particles and precipitates out. For this reason, the obtained sludge has reduced sedimentation, concentration and dehydration properties, and the precipitated hydroxide is dispersed in the supernatant water and overflows from the sedimentation tank, so that a satisfactory treated water quality can be obtained. There is a problem that can not be. Therefore, an object of the present invention is to separate metals in metal-containing wastewater containing various metals in addition to ferric iron, it is extremely efficient, and the generated sludge has a low moisture content, so that sludge treatment is easy. An object of the present invention is to provide a method for treating a metal-containing wastewater.
【０００４】[0004]
【問題点を解決する為の手段】上記目的は以下の本発明
によって達成される。即ち、本発明は、第二鉄イオンと
他の重金属イオンとが混在する金属含有排水を、第一反
応槽においてアルカリを添加してｐＨを３〜５．５に調
整し、第二反応槽においてアルカリを添加してｐＨを
６．５〜８．３に調整し、生成した金属の水酸化物を凝
集槽において高分子凝集剤を添加して凝集させ、次いで
金属の水酸化物を沈澱分離する金属含有排水の処理方法
において、沈澱槽で沈降分離したスラッジの一部を取り
出して、そのまま上記第一反応槽及び第二反応槽に添加
混合することを特徴とする金属含有排水の処理方法であ
る。The above object is achieved by the present invention described below. That is, in the present invention, a metal-containing wastewater in which ferric ions and other heavy metal ions are mixed is adjusted to pH 3 to 5.5 by adding alkali in a first reaction tank, and in a second reaction tank. The pH is adjusted to 6.5 to 8.3 by adding an alkali, and the generated metal hydroxide is aggregated by adding a polymer coagulant in an aggregation tank, and then the metal hydroxide is separated by precipitation. In the method for treating metal-containing wastewater, a part of the sludge settled and separated in the sedimentation tank is taken out, and the mixture is directly added to and mixed with the first reaction tank and the second reaction tank. .
【０００５】[0005]
【作用】溶存金属を水酸化物として折出沈澱させる処理
ｐＨ領域を、第一反応槽においてｐＨ＝３〜５．５と
し、且つ第二反応槽においてｐＨ＝６．５〜８．３に２
段階に調整し、夫々沈澱槽で沈降分離したスラッジを混
合することにより、第一反応槽では第二鉄（Ｆｅ3+）イ
オンが先ず折出沈澱し、第二反応槽でその他の金属類が
折出沈澱する。この様にして排水中に含有するすべての
金属イオンが結晶性の緻密なスラッジとして得られ、沈
降性、濃縮性及び脱水性が極めて高く維持される。又、
上澄水中に微細な金属水酸化物も分散せず十分満足し得
る処理水水質を得ることが出来る。The pH range of the treatment for depositing and dissolving the dissolved metal as hydroxide is adjusted to pH = 3 to 5.5 in the first reactor and to pH = 6.5 to 8.3 in the second reactor.
By adjusting the stages and mixing the sludge settled and separated in the respective sedimentation tanks, ferric (Fe 3+ ) ions first precipitate out in the first reaction tank, and other metals are precipitated in the second reaction tank. It precipitates out. In this way, all the metal ions contained in the wastewater are obtained as crystalline dense sludge, and sedimentation, concentration and dehydration are kept extremely high. or,
Fine metal hydroxides are not dispersed in the supernatant water, so that a sufficiently satisfactory treated water quality can be obtained.
【０００６】[0006]
【好ましい実施態様】次に好ましい実施態様を挙げて本
発明を更に具体的に説明する。図１〜４は本発明の好ま
しい実施態様を説明する図である。先ず、工場排水であ
る第二鉄イオンと他の重金属イオンとが混在する金属含
有排水を原水（被処理水）として、予備中和槽に導入
し、この予備中和槽において被処理水のｐＨを好ましく
は２〜３に調整する。このｐＨ調整は被処理水が通常か
なりの酸を含有しているので、被処理水中の遊離の酸を
無くす為に行う。従って原水がｐＨ２〜３である場合に
は、予備中和槽を使用せず、被処理水を直ちに第一反応
槽に導入することが出来る。又、原水が既にｐＨ３以上
であり、第二鉄イオンが析出沈澱している場合には、原
水のｐＨを２〜３に調製して析出沈澱している水酸化第
二鉄を溶解してから第一反応槽に導入する。予備中和槽
及び後の工程でｐＨ調整に使用するアルカリ剤として
は、苛性ソーダ、消石灰、生石灰等の通常のアルカリ剤
が使用され、酸としては塩酸、硫酸等の通常の酸が使用
される。Next, the present invention will be described more specifically with reference to preferred embodiments. 1 to 4 are views for explaining a preferred embodiment of the present invention. First, metal-containing wastewater in which ferric ions and other heavy metal ions, which are factory wastewaters, are mixed and introduced into a pre-neutralization tank as raw water (water to be treated). Is preferably adjusted to 2-3. This pH adjustment is performed to eliminate free acids in the water to be treated, since the water to be treated usually contains a considerable amount of acid. Therefore, when the raw water has a pH of 2 to 3, the water to be treated can be immediately introduced into the first reaction tank without using the preliminary neutralization tank. If the raw water is already at pH 3 or more and ferric ions are precipitated and precipitated, adjust the pH of the raw water to 2 to 3 to dissolve the precipitated and precipitated ferric hydroxide. It is introduced into the first reaction tank. As the alkaline agent used for the pH adjustment in the pre-neutralization tank and in the subsequent steps, ordinary alkaline agents such as caustic soda, slaked lime, quick lime and the like are used, and as the acid, ordinary acids such as hydrochloric acid and sulfuric acid are used.
【０００７】次に被処理水は第一反応槽に導かれ、ｐＨ
３〜５．５に調整される。このｐＨ調整は図１及び図２
に示す例では、沈澱槽から返送されたスラッジを第一ス
ラッジ反応槽（図２：スラッジ反応槽）においてアルカ
リ処理されたアルカリスラッジの添加によって行われる
が、図３及び図４に示す様に、返送スラッジを直接第一
反応槽に添加すると共に、第一反応槽内の被処理水のｐ
Ｈを３〜５．５にする量のアルカリ剤を別途添加して行
ってもよい。第一スラッジ反応槽（図２：スラッジ反応
槽）に添加されるアルカリ量は、第一反応槽に添加され
た時に第一反応槽内の被処理液のｐＨが３〜５．５にな
る量である。第一反応槽において、ｐＨが３未満である
と第二鉄イオンの水酸化物化が不十分であり、第二鉄の
析出が充分には行われない。一方、ｐＨが５．５を越え
ると第二鉄イオン以外の金属イオンまで水酸化物とな
り、生成する水酸化物の密度が低く、後の工程における
凝集沈降が不十分となる。Next, the water to be treated is led to the first reaction tank,
It is adjusted to 3-5.5. This pH adjustment is shown in FIGS.
In the example shown in FIG. 3, the sludge returned from the precipitation tank is added by alkali sludge treated in the first sludge reaction tank (FIG. 2: sludge reaction tank) by alkali treatment, as shown in FIGS. 3 and 4. Return sludge is directly added to the first reaction tank, and the amount of water to be treated in the first reaction tank is reduced.
It may be performed by separately adding an alkali agent in an amount to make H 3 to 5.5. The amount of alkali added to the first sludge reaction tank (FIG. 2: sludge reaction tank) is such that when added to the first reaction tank, the pH of the liquid to be treated in the first reaction tank becomes 3 to 5.5. It is. In the first reaction tank, when the pH is less than 3, hydroxide of ferric ions is insufficient, and ferric iron is not sufficiently precipitated. On the other hand, when the pH exceeds 5.5, metal ions other than ferric ions are converted into hydroxides, the density of the generated hydroxide is low, and the coagulation and sedimentation in the subsequent steps become insufficient.
【０００８】第一反応槽に添加されるアルカリスラッジ
又はアルカリ処理されていないスラッジは、第一反応槽
において被処理水から析出する水酸化第二鉄の結晶化或
は凝集化の核剤或は触媒として作用するものと思われ
る。スラッジの添加量（固形分）は特に限定されない
が、第一反応槽で被処理水中から発生する第二鉄水酸化
物量に対して１１〜２５倍量（重量）の範囲が好まし
い。添加量が１１倍未満であると、新たに析出する水酸
化第二鉄の捕捉、凝集化及び緻密化が不十分であり、後
の沈降分離が不満足となる。一方、２５倍を越える量で
は全工程における処理効率が低下する。第一反応槽にお
ける反応時間（滞留時間）は撹拌装置（Ｍ）の撹拌効
率、被処理水の性状及び処理量等によって変化するが、
通常は約５〜１５分間程度である。The alkali sludge added to the first reaction tank or the sludge not subjected to alkali treatment is used as a nucleating agent or a nucleating agent for crystallization or agglomeration of ferric hydroxide precipitated from water to be treated in the first reaction tank. It seems to act as a catalyst. The amount of sludge added (solid content) is not particularly limited, but is preferably in the range of 11 to 25 times (by weight) the amount of ferric hydroxide generated from the water to be treated in the first reaction tank. If the addition amount is less than 11 times, trapping, agglomeration and densification of newly precipitated ferric hydroxide will be insufficient, and subsequent sedimentation and separation will be unsatisfactory. On the other hand, if the amount exceeds 25 times, the processing efficiency in all the steps is reduced. The reaction time (residence time) in the first reaction tank varies depending on the stirring efficiency of the stirring device (M), the properties of the water to be treated, the amount of treatment, and the like.
Usually, it is about 5 to 15 minutes.
【０００９】続いて被処理水は第二反応槽に導かれ、ｐ
Ｈ６．５〜８．３に調整される。このｐＨ調整は図１に
示す例では、沈澱槽から返送されたスラッジを第二スラ
ッジ反応槽においてアルカリ処理されたアルカリスラッ
ジによって行われるが、図２及び図３に示す様に、スラ
ッジ反応槽からのアルカリスラッジと別途添加されるア
ルカリ剤によって行ってもよく、更に図４に示す様に、
スラッジをアルカリ処理しない場合には別途添加される
アルカリ剤の添加によって行ってもよい。Subsequently, the water to be treated is led to the second reaction tank, where p
H is adjusted to 6.5 to 8.3. In the example shown in FIG. 1, the pH is adjusted by alkali sludge obtained by subjecting the sludge returned from the precipitation tank to alkali treatment in the second sludge reaction tank. As shown in FIGS. 2 and 3, the pH is adjusted from the sludge reaction tank. It may be carried out by using an alkali sludge and an alkali agent separately added, as shown in FIG.
If the sludge is not alkali-treated, it may be performed by adding an alkali agent added separately.
【００１０】第二スラッジ反応槽に添加されるアルカリ
量は、図１に示す例では第二反応槽に添加された時に第
二反応槽内の被処理液のｐＨが６．５〜８．３になる量
であるが、図２及び図３に示す例では、第一反応槽に添
加された時に第一反応槽内の被処理液のｐＨが３〜５．
５になる量であり、このアルカリ量では第二反応槽内の
被処理水のｐＨ調整に不十分である時は別途アルカリ剤
を添加する。又、図４に示す例では、第二反応槽に、第
二反応槽内の被処理液のｐＨが６．５〜８．３になる量
のアルカリ剤が添加される。In the example shown in FIG. 1, the amount of alkali added to the second sludge reaction tank is such that the pH of the liquid to be treated in the second reaction tank when added to the second reaction tank is 6.5 to 8.3. In the examples shown in FIGS. 2 and 3, the pH of the liquid to be treated in the first reaction tank when added to the first reaction tank is 3 to 5.
When the alkali amount is insufficient for adjusting the pH of the water to be treated in the second reaction tank, an alkali agent is added separately. In the example shown in FIG. 4, an alkali agent is added to the second reaction tank in such an amount that the pH of the liquid to be treated in the second reaction tank becomes 6.5 to 8.3.
【００１１】第二反応槽において、ｐＨが６．５未満で
あると第二鉄イオン以外の金属イオンの水酸化物化が不
十分であり、これらの金属イオンの析出が充分には行わ
れない。一方、ｐＨが８．３を越えると、亜鉛、鉛、ア
ルミニウム等の両性元素が再溶解する可能性が高くな
り、又、使用するアルカリ剤の量も増加するので、いず
れにしても処理効率上好ましくない。第二反応槽に添加
されるアルカリスラッジ又はアルカリ処理されていない
スラッジの作用及び添加量は第一反応槽の場合と同様で
ある。第二反応槽における反応時間（滞留時間）は撹拌
装置（Ｍ）の撹拌効率、被処理水の性状及び処理量等に
よって変化するが、通常は約５〜１５分間程度である。
又、被処理水が第一鉄イオンを有意の量で含む場合に
は、第二反応槽で空気曝気を行い、第一鉄イオンを第二
鉄イオンに酸化して他の金属イオンと共に水酸化物とし
て析出させる。第一鉄イオンの酸化には空気曝気する他
に、オゾンや過酸化水素等を酸化剤として添加してもよ
い。In the second reaction tank, if the pH is less than 6.5, hydroxides of metal ions other than ferric ions are insufficient, and these metal ions are not sufficiently precipitated. On the other hand, if the pH exceeds 8.3, the possibility of re-dissolving amphoteric elements such as zinc, lead, and aluminum increases, and the amount of the alkaline agent used also increases. Not preferred. The action and amount of alkali sludge added to the second reaction tank or sludge not subjected to alkali treatment are the same as those in the first reaction tank. The reaction time (residence time) in the second reaction tank varies depending on the stirring efficiency of the stirring device (M), the properties of the water to be treated, the throughput, and the like, but is usually about 5 to 15 minutes.
If the water to be treated contains ferrous ions in a significant amount, air is aerated in the second reaction tank to oxidize ferrous ions to ferric ions and hydroxylate them with other metal ions. Is deposited as a material. To oxidize ferrous ions, ozone or hydrogen peroxide may be added as an oxidizing agent in addition to aeration with air.
【００１２】続いて被処理水は、金属の水酸化物を析出
させた状態で凝集槽に送られる。凝集槽では、撹拌され
ながら公知の高分子凝集剤が添加される。高分子凝集剤
の添加量は、被処理水の高分子凝集剤濃度が約２〜５ｍ
ｇ／リットル程度となる量が一般的である。凝集剤添加
により被処理水中に析出している金属の水酸化物は、被
処理水に加えられた返送スラッジと共に大きな凝集フロ
ックとなる。凝集槽のおける処理時間（滞留時間）は撹
拌装置（Ｍ）の撹拌効率、被処理水の性状及び処理量等
によって変化するが、通常は約５〜１５分間程度であ
る。最後に被処理水は沈澱槽に導かれ、静置によって凝
集フロックは沈降し、上澄み液は必要に応じてｐＨ調整
されて処理済水として放流される。沈降した凝集フロッ
ク（スラッジ）の一部は返送スラッジとして処理系に返
送され、余剰のスラッジは余剰汚泥として排出及び処理
される。沈澱槽における処理時間（滞留時間）は生成し
た凝集フロックの性状、濃度、被処理水の性状及び処理
量等によって変化するが、通常は約０．５〜３時間程度
である。Subsequently, the water to be treated is sent to a coagulation tank in a state where metal hydroxide is precipitated. In the flocculation tank, a known polymer flocculant is added while stirring. The addition amount of the polymer flocculant is such that the concentration of the polymer flocculant in the water to be treated is about 2 to 5 m.
An amount of about g / liter is common. The metal hydroxide precipitated in the water to be treated due to the addition of the flocculant becomes a large flocculated floc together with the return sludge added to the water to be treated. The treatment time (residence time) in the flocculation tank varies depending on the stirring efficiency of the stirring device (M), the properties of the water to be treated, the treatment amount, and the like, but is usually about 5 to 15 minutes. Finally, the water to be treated is led to a sedimentation tank, and the flocculated floc is sedimented by standing, and the pH of the supernatant is adjusted as required and discharged as treated water. Part of the settled flocculated flocs (sludge) is returned to the treatment system as return sludge, and excess sludge is discharged and treated as excess sludge. The treatment time (residence time) in the precipitation tank varies depending on the properties and concentration of the formed floc, the properties of the water to be treated, the amount of treatment and the like, but is usually about 0.5 to 3 hours.
【００１３】[0013]
【実施例】次に図面に示す実施例により本発明を更に具
体的に説明する。 実施例１（図１参照） 塩化第一鉄によりＦｅ2+＝２００ｍｇ／リットル及び塩
化第二鉄によりＦｅ3+＝２００ｍｇ／リットルの濃度に
調整し、塩酸を加えて液のｐＨを１．５に調整した模擬
排水を作製した。この模擬排水と図１に示す実験装置を
用いて、模擬排水を１リットル／ｍｉｎ．の流量で予備
中和槽に連続的に供給し、液のｐＨを予め２．５に調節
した後、第一反応槽において、沈澱槽で沈澱分離したス
ラッジを第一スラッジ反応槽に循環返送し、アルカリ剤
として消石灰懸濁液を添加してアルカリスラッジとし、
該アルカリスラッジを上記予備中和された排水に添加
し、混合液のｐＨを４に調節し、Ｆｅ3+を水酸化物とし
て折出させた（第一スラッジ反応槽に添加するアルカリ
量は第一反応槽の混合液がｐＨ＝４となる量である）。Next, the present invention will be described more specifically with reference to the embodiments shown in the drawings. Example 1 (see FIG. 1) The concentration of Fe 2+ was adjusted to 200 mg / L with ferrous chloride and the concentration of Fe 3+ was 200 mg / L with ferric chloride, and hydrochloric acid was added to adjust the pH of the solution to 1.5. Simulated drainage was prepared. Using the simulated waste water and the experimental apparatus shown in FIG. After continuously adjusting the pH of the liquid to 2.5 in advance, the sludge precipitated and separated in the sedimentation tank is circulated back to the first sludge reaction tank in the first reaction tank. , A slaked lime suspension is added as an alkali agent to form an alkali sludge,
The alkali sludge was added to the pre-neutralized wastewater, the pH of the mixture was adjusted to 4, and Fe 3+ was precipitated as hydroxide (the amount of alkali added to the first sludge reaction tank was This is the amount at which the mixed solution in one reaction tank becomes pH = 4).
【００１４】次いで、第一反応槽での処理液を第二反応
槽に送り、沈澱槽で沈澱分離したスラッジを第二スラッ
ジ反応槽に循環返送し、アルカリ剤として消石灰懸濁液
を添加してアルカリスラッジとし、該アルカリスラッジ
を上記第二反応槽に添加し、第二反応槽の混合液のｐＨ
を８に調節しながら空気曝気によりＦｅ2+の酸化を行
い、鉄水酸化物として折出させた（第二スラッジ反応槽
に添加するアルカリ量は、第二反応槽混合液がｐＨ＝８
となる量である）。第二反応槽での処理が完了した混合
液を凝集槽に送り、凝集槽で高分子凝集剤を４ｍｇ／リ
ットルの濃度になる様に添加して析出した水酸化物を凝
集させ、凝集したフロックを沈澱槽で沈降分離し、上澄
水は処理水として排出した。沈降分離したスラッジは沈
澱槽内で滞留濃縮後、返送スラッジとして第一スラッジ
反応槽及び第二スラッジ反応槽へ循環返送した。循環返
送したスラッジの量はＳＳ量として、第一反応槽及び第
二反応槽で折出する金属水酸化物量の２０倍量とした。Next, the processing solution in the first reaction tank is sent to the second reaction tank, the sludge precipitated and separated in the precipitation tank is circulated back to the second sludge reaction tank, and a slaked lime suspension is added as an alkali agent. Alkali sludge was added to the second reaction tank, and the pH of the mixture in the second reaction tank was adjusted.
Was adjusted to 8 to oxidize Fe 2+ by aeration with air to be precipitated out as iron hydroxide (the amount of alkali added to the second sludge reaction tank was adjusted to pH = 8
Is the amount). The mixed solution after the treatment in the second reaction tank is sent to the flocculation tank, and a polymer flocculant is added to the flocculation tank so as to have a concentration of 4 mg / liter, and the precipitated hydroxide is flocculated. Was separated by settling in a sedimentation tank, and the supernatant water was discharged as treated water. The sludge separated by settling was retained and concentrated in the sedimentation tank, and then returned to the first sludge reaction tank and the second sludge reaction tank as return sludge. The amount of sludge circulated and returned was 20 times the amount of metal hydroxide fed out in the first and second reaction tanks as the SS amount.
【００１５】実施例２（図２参照） 沈澱槽で沈澱したスラッジの一部をスラッジ反応槽に返
送し、アルカリ剤として消石灰懸濁液を添加してアルカ
リスラッジとした。該アルカリスラッジを第一反応槽及
び第二反応槽に夫々分注した。スラッジ反応槽に循環返
送するスラッジ量はＳＳ量として第一反応槽及び第二反
応槽で折出する金属水酸化物量の合計量の２０倍とし
た。又、第一反応槽及び第二反応槽に添加するアルカリ
スラッジの量はＳＳ量として第一反応槽及び第二反応槽
の夫々で折出する金属水酸化物量の２０倍量として添加
した。スラッジ反応槽へ添加するアルカリ剤の添加量は
第一反応槽混合液がｐＨ＝４となる量とし、第二反応槽
でアルカリ剤が不足する場合は別途第二反応槽へ直接ア
ルカリ剤を添加して第二反応槽ｐＨを８に調節した。そ
の他の操作は実施例１と同様に行った。Example 2 (see FIG. 2) A part of the sludge settled in the settling tank was returned to the sludge reaction tank, and a slaked lime suspension was added as an alkali agent to form an alkali sludge. The alkali sludge was dispensed into a first reaction tank and a second reaction tank, respectively. The amount of sludge circulated and returned to the sludge reaction tank was 20 times as much as the total amount of metal hydroxides fed out in the first and second reaction tanks as the SS amount. The amount of alkali sludge added to the first reaction tank and the second reaction tank was 20 times the amount of metal hydroxide deposited in each of the first reaction tank and the second reaction tank as the SS amount. The amount of the alkali agent added to the sludge reaction tank is such that the pH of the mixed liquid in the first reaction tank becomes 4, and when the alkali agent is insufficient in the second reaction tank, the alkali agent is separately added directly to the second reaction tank. Then, the pH of the second reaction tank was adjusted to 8. Other operations were performed in the same manner as in Example 1.
【００１６】参考例（図３参照） 第一反応槽へは、沈澱槽から取り出したスラッジを直接
循環返送し、又、第一反応槽へ直接アルカリ剤を添加し
て第一反応槽混合液のｐＨを４に調節した。又、第二反
応槽には、沈澱槽からのスラッジをスラッジ反応槽へ循
環返送し、該スラッジ反応槽でアルカリ剤を添加してア
ルカリスラッジとした後、該アルカリスラッジを第二反
応槽へ添加した。スラッジ反応槽へ添加するアルカリ剤
の量は第二反応槽混合液がｐＨ＝８となる量とした。そ
の他の操作は実施例１と同様に行った。 Reference Example (see FIG. 3) The sludge taken out of the precipitation tank is directly circulated and returned to the first reaction tank, and an alkali agent is directly added to the first reaction tank to mix the liquid mixture in the first reaction tank. The pH was adjusted to 4. In the second reaction tank, the sludge from the precipitation tank is circulated back to the sludge reaction tank, and an alkali agent is added in the sludge reaction tank to form an alkali sludge, and then the alkali sludge is added to the second reaction tank. did. The amount of the alkali agent added to the sludge reaction tank was such that the pH of the mixed liquid in the second reaction tank reached 8. Other operations were performed in the same manner as in Example 1.
【００１７】実施例３（図４参照） 第一反応槽及び第二反応槽の夫々に、沈澱槽からのスラ
ッジをそのまま循環返送し、第一反応槽及び第二反応槽
の夫々に直接アルカリ剤を添加し、第一反応槽混合液の
ｐＨを４に、そして第二反応槽混合液のｐＨを８に調節
した。その他の操作は実施例１と同様に行った。Example 3 (See FIG. 4) The sludge from the precipitation tank was directly circulated and returned to each of the first and second reaction tanks, and the alkaline agent was directly fed to each of the first and second reaction tanks. Was added to adjust the pH of the first reactor mixture to 4 and the pH of the second reactor mixture to 8. Other operations were performed in the same manner as in Example 1.
【００１８】比較例１ 図１に示す実験装置におて、スラッジ反応槽を１槽と
し、且つ第一反応槽と第二反応槽を分けずに１槽とした
実験装置により、沈澱槽より循環返送するスラッジをス
ラッジ反応槽に返送し、アルカリ剤として消石灰懸濁液
を添加してアルカリスラッジとし、該アルカリスラッジ
を反応槽に添加し、反応槽混合液のｐＨを８に調節し
た、循環返送するスラッジ量はＳＳ量として反応槽で折
出する金属水酸化物量の２０倍量とした。スラッジ反応
槽へ添加するアルカリ剤の量は反応槽混合液がｐＨ＝８
となる量とした。又、凝集槽で添加する高分子凝集剤量
は４ｍｇ/ リットルとした。その他の操作は実施例１と
同様に行った。COMPARATIVE EXAMPLE 1 In the experimental apparatus shown in FIG. 1, a sludge reaction tank was used as one tank, and the first reaction tank and the second reaction tank were separated and used as one tank, and circulated from the precipitation tank. The sludge to be returned is returned to the sludge reaction tank, slaked lime suspension is added as an alkali agent to form an alkali sludge, and the alkali sludge is added to the reaction tank, and the pH of the reaction mixture is adjusted to 8 by circulation return. The amount of sludge to be used was 20 times the amount of metal hydroxide deposited in the reaction tank as the amount of SS. The amount of the alkaline agent added to the sludge reaction tank was adjusted to pH = 8
It became the quantity which becomes. The amount of the polymer flocculant added in the flocculation tank was 4 mg / liter. Other operations were performed in the same manner as in Example 1.
【００１９】実施例１〜実施例３、参考例及び比較例に
おいて、余剰汚泥として排出したスラッジの性状は以下
の通りとなった。 （１）汚泥の濃縮性 各実施例、参考例及び比較例における沈澱槽からの排泥
濃度を表１に示す。In Examples 1 to 3, Reference Example and Comparative Example, the properties of sludge discharged as excess sludge were as follows. (1) Concentration of sludge Table 1 shows the concentration of sludge discharged from the sedimentation tank in each Example , Reference Example and Comparative Example.
【表１】 沈澱槽排泥濃度 〔単位：重量％〕[Table 1] Sedimentation tank sludge concentration [Unit:% by weight]
【００２０】（２）汚泥の沈降性 各実施例、参考例及び比較例における凝集槽混合液を１
リットルメスシリンダーに分取し、静置沈澱させた場合
の沈降開始から１分間の沈降速度を表２に示す。(2) Sedimentation of sludge The coagulation tank mixture in each of Examples , Reference Examples and Comparative Examples was
Table 2 shows the sedimentation speed for 1 minute from the start of sedimentation when the liquid was collected in a liter measuring cylinder and allowed to stand still.
【表２】 汚泥の沈降速度 〔単位：ｍ／Ｈｒ〕[Table 2] Sludge settling speed [Unit: m / Hr]
【００２１】（３）汚泥の脱水性 各実施例、参考例及び比較例における沈澱槽より排泥し
た表１に示したＳＳ濃度のスラッジについて、加圧脱水
した場合の脱水速度及び脱水ケーキの含水率を表３に示
す。(3) Dewatering property of sludge Dewatering speed and water content of dewatered cake when sludge under pressure was applied to sludge having the SS concentration shown in Table 1 discharged from the settling tank in each of Examples , Reference Examples and Comparative Examples. The rates are shown in Table 3.
【表３】 汚泥の脱水速度と脱水ケーキ含水率 〔単位：脱水速度＝ｋｇ−ＳＳ／ｍ2・Ｈｒ、脱水ケー
キ含水率＝重量％〕[Table 3] Dewatering rate of sludge and water content of dewatered cake [Unit: dehydration rate = kg-SS / m 2 · Hr, dehydrated cake water content =% by weight]
【００２２】[0022]
【効果】以上に示す様に、本発明によれば、本発明の方
法で得られる沈澱槽で沈降分離した汚泥（スラッジ）
は、従来方法である比較例に比べて、沈降性、濃縮性及
び脱水性が何れも著しく優れていることが明らかであ
る。As described above, according to the present invention, sludge settled and separated in the settling tank obtained by the method of the present invention (sludge).
It is clear that the sedimentation, the concentration and the dehydration are all remarkably superior to those of the comparative example which is a conventional method.
【００２３】[0023]
【図１】本発明の方法の１実施例を説明する図。 FIG. 1 is a diagram illustrating one embodiment of the method of the present invention .
【図２】本発明の方法の１実施例を説明する図。 FIG. 2 is a diagram illustrating one embodiment of the method of the present invention .
【図３】参考例を説明する図。 FIG. 3 illustrates a reference example .
【図４】本発明の方法の１実施例を説明する図。 FIG. 4 is a diagram illustrating one embodiment of the method of the present invention .
───────────────────────────────────────────────────── フロントページの続き (72)発明者 菅家 能成 東京都千代田区鍛冶町１−５−７ 環境 エンジニアリング株式会社内 (56)参考文献 特開 平６−182359（ＪＰ，Ａ) 特開 昭53−28954（ＪＰ，Ａ) 特開 昭55−19643（ＪＰ，Ａ) 特開 昭51−103076（ＪＰ，Ａ) 特開 平３−137987（ＪＰ，Ａ) 特公 昭55−19643（ＪＰ，Ｂ１) (58)調査した分野(Int.Cl.7，ＤＢ名) C02F 1/62,1/56 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshinari Sugaya 1-5-7 Kaji-cho, Chiyoda-ku, Tokyo Environmental Engineering Co., Ltd. (56) References JP-A-6-182359 (JP, A) JP-A Sho53 -28954 (JP, A) JP-A-55-19643 (JP, A) JP-A-51-103076 (JP, A) JP-A-3-137987 (JP, A) JP-B-55-19643 (JP, B1) (58) Fields surveyed (Int. Cl. 7 , DB name) C02F 1 / 62,1 / 56
Claims (5)
在する金属含有排水を、第一反応槽においてアルカリを
添加してｐＨを３〜５．５に調整し、第二反応槽におい
てアルカリを添加してｐＨを６．５〜８．３に調整し、
生成した金属の水酸化物を凝集槽において高分子凝集剤
を添加して凝集させ、次いで金属の水酸化物を沈澱分離
する金属含有排水の処理方法において、沈澱槽で沈降分
離したスラッジの一部を取り出して、そのまま上記第一
反応槽及び第二反応槽に添加混合することを特徴とする
金属含有排水の処理方法。1. A metal-containing wastewater in which ferric ions and other heavy metal ions are mixed, the pH is adjusted to 3 to 5.5 by adding an alkali in a first reaction tank, and the alkali is added in a second reaction tank. To adjust the pH to 6.5 to 8.3,
In a method for treating metal-containing waste water in which a generated metal hydroxide is coagulated by adding a polymer coagulant in a coagulation tank and then separating and separating the metal hydroxide, a part of the sludge settled and separated in the settling tank the removed directly processing method of a metal-containing waste water, which comprises mixing added to the first reaction vessel and second reaction vessel.
処理した上記スラッジのアルカリスラッジをアルカリ剤
として添加する請求項１に記載の金属含有排水の処理方
法。」2. The first reaction tank and the second reaction tank are charged with alkali.
Alkaline sludge of the treated sludge
The method for treating a metal-containing wastewater according to claim 1, which is added as a water. "
Ｈを予めｐＨ２〜３に調整する請求項１に記載の金属含
有排水の処理方法。3. The metal-containing wastewater p before being led to the first reaction tank.
The method for treating metal-containing wastewater according to claim 1, wherein H is adjusted to pH 2 to 3 in advance.
求項１に記載の金属含有排水の処理方法。4. The method for treating metal-containing wastewater according to claim 1, wherein the treatment liquid in the second reaction tank is aerated with air.
ラッジの量を、第一反応槽及び第二反応槽で原水中から
発生する金属水酸化物量に対して１１〜２５倍量とする
請求項１に記載の金属含有排水の処理方法。5. The amount of sludge to be added to the first reaction tank and the second reaction tank is 11 to 25 times the amount of metal hydroxide generated from raw water in the first reaction tank and the second reaction tank. The method for treating metal-containing wastewater according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2492494A JP3325689B2 (en) | 1994-01-28 | 1994-01-28 | Treatment method for metal-containing wastewater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2492494A JP3325689B2 (en) | 1994-01-28 | 1994-01-28 | Treatment method for metal-containing wastewater |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07214073A JPH07214073A (en) | 1995-08-15 |
| JP3325689B2 true JP3325689B2 (en) | 2002-09-17 |
Family
ID=12151684
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2492494A Expired - Lifetime JP3325689B2 (en) | 1994-01-28 | 1994-01-28 | Treatment method for metal-containing wastewater |
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| Country | Link |
|---|---|
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|---|---|---|---|---|
| JP3842907B2 (en) * | 1998-10-09 | 2006-11-08 | 新日本製鐵株式会社 | Treatment of metal-containing wastewater and method for recovering valuable metals |
| JP4591641B2 (en) * | 2000-12-05 | 2010-12-01 | Ｎｅｃファシリティーズ株式会社 | Method for coagulating and precipitating iron hydroxide in wastewater containing concentrated inorganic components |
| JP4894139B2 (en) * | 2004-10-28 | 2012-03-14 | 栗田工業株式会社 | Method and apparatus for treating phosphoric acid-containing liquid |
| JP4947640B2 (en) * | 2007-01-31 | 2012-06-06 | 日新製鋼株式会社 | Waste acid solution treatment method |
| JP5507318B2 (en) * | 2010-04-20 | 2014-05-28 | 新日鐵住金株式会社 | Treatment method for wastewater containing metal ions |
| JP5693992B2 (en) * | 2011-02-14 | 2015-04-01 | 新日鐵住金株式会社 | Method for recovering dissolved iron from wastewater containing various metal ions |
| JP5965164B2 (en) * | 2012-03-09 | 2016-08-03 | Ｄｏｗａテクノロジー株式会社 | Cadmium-containing wastewater treatment method |
| JP7238686B2 (en) * | 2019-08-15 | 2023-03-14 | 住友金属鉱山株式会社 | Neutralization method |
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1994
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