JPH08132069A - Treatment of metal-containing waste water - Google Patents
Treatment of metal-containing waste waterInfo
- Publication number
- JPH08132069A JPH08132069A JP26967794A JP26967794A JPH08132069A JP H08132069 A JPH08132069 A JP H08132069A JP 26967794 A JP26967794 A JP 26967794A JP 26967794 A JP26967794 A JP 26967794A JP H08132069 A JPH08132069 A JP H08132069A
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- Prior art keywords
- sludge
- metal
- concentration
- pipe
- pressure
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は金属含有排水の処理方法
に係り、特に金属含有排水を中和して不溶性金属水酸化
物を生成させ、この水酸化物を含む汚泥と処理水とに分
離し、分離した汚泥を中和工程に返送する金属含有排水
の処理方法において、返送汚泥濃度を簡単な設備で迅速
にかつ適確に求めることにより、高濃度汚泥を得るため
に必要な汚泥返送量の制御を確実に行う方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating metal-containing wastewater, and particularly to neutralize the metal-containing wastewater to produce an insoluble metal hydroxide, which is separated into sludge containing this hydroxide and treated water. However, in the method for treating metal-containing wastewater that returns separated sludge to the neutralization process, the amount of sludge to be returned to obtain high-concentration sludge by quickly and accurately determining the concentration of returned sludge with simple equipment. Method for surely controlling
【０００２】[0002]
【従来の技術】金属含有排水の処理において、濃縮性に
富み、脱水性に優れた高濃度重金属水酸化物汚泥を得る
方法として、アルカリ汚泥法がある。この方法は、重金
属含有排水にアルカリ剤を直接添加せずに、後工程のシ
ックナーの排泥の一部と混合して（以下、アルカリと汚
泥の混合物を「アルカリ汚泥」と称す。）添加する方法
である（特公昭６１−１５６号公報）。即ち、アルカリ
汚泥法の原理は、汚泥にアルカリを添加し、汚泥に吸着
されたアルカリで原水（金属含有排水）を中和すること
にある。2. Description of the Related Art In the treatment of metal-containing wastewater, there is an alkali sludge method as a method for obtaining a high-concentration heavy metal hydroxide sludge that is rich in concentration and excellent in dehydration. In this method, the alkaline agent is not directly added to the heavy metal-containing wastewater, but is mixed with a part of the sludge of the post-process thickener (hereinafter, the mixture of alkali and sludge is referred to as "alkaline sludge"). Method (Japanese Patent Publication No. 61-156). That is, the principle of the alkaline sludge method is to add an alkali to the sludge and neutralize the raw water (metal-containing wastewater) with the alkali adsorbed on the sludge.
【０００３】このようなアルカリ汚泥法において、汚泥
分離工程から返送し、アルカリと混合して原水に添加す
る返送汚泥量については、下記式で算出される汚泥返送
比Ｒが運転管理の指標として用いられ、この返送比Ｒは
原水中に含有される金属の種類によっても異なるが、通
常の場合、１５〜４０の範囲となるように、返送汚泥量
が制御される（特開平５−５７２９２号公報）、即ち、
原水量、発生ＳＳ量、汚泥濃度を測定し、これらの測定
値から、下記式より算出される返送比（Ｒ）が１５〜４
０の範囲で、経験上又は事前試験により確認された値と
なるように、返送汚泥量が制御されている。In such an alkaline sludge method, the sludge return ratio R calculated by the following formula is used as an index for operation control for the amount of the returned sludge returned from the sludge separation step, mixed with alkali and added to the raw water. The return ratio R varies depending on the type of metal contained in the raw water, but in the normal case, the amount of returned sludge is controlled so as to fall within the range of 15 to 40 (JP-A-5-57292). ), That is,
The amount of raw water, the amount of generated SS, and the sludge concentration were measured, and the return ratio (R) calculated from the following formulas was 15 to 4 from these measured values.
In the range of 0, the amount of sludge to be returned is controlled so as to be the value confirmed by experience or preliminary test.
【０００４】[0004]
【数１】 [Equation 1]
【０００５】このように汚泥返送比Ｒに基いて返送汚泥
量を制御することにより、得られる汚泥濃度は従来の２
〜３％から２０〜３０％と、大幅に向上する。By controlling the amount of sludge to be returned based on the sludge return ratio R, the sludge concentration obtained is 2
Significantly improved from ~ 3% to 20-30%.
【０００６】図５は、従来の返送汚泥量の制御システム
を示す系統図である。FIG. 5 is a system diagram showing a conventional control system for returning sludge amount.
【０００７】図５において、１１は原水（重金属含有排
水）の導入管であり、中和槽１に原水を導入する。１Ａ
は中和槽１に設けられたｐＨ計である。１２は中和槽１
内の液を、ｐＨ計２Ａを備える凝集槽２に送給する配管
である。１３は凝集槽２内の液を沈殿槽（シックナー）
３に送給する配管であり、１４は処理水の排出配管、１
５は沈殿槽３で分離された汚泥の抜出管であり、汚泥を
図示しない脱水機へ送る排出配管１６と、アルカリ混合
槽４に返送する返送配管１７とに分岐している。１８は
アルカリ貯槽５内のアルカリを供給する配管であり、中
和槽１への供給配管１８Ａとアルカリ混合槽４への供給
配管１８Ｂとに分岐している。１９は凝集槽２にポリマ
ー（高分子凝集剤）を供給する配管であり、２０はアル
カリ混合槽４からアルカリ汚泥を中和槽２に送給する配
管である。In FIG. 5, reference numeral 11 denotes a raw water (heavy metal-containing wastewater) introduction pipe, which introduces the raw water into the neutralization tank 1. 1A
Is a pH meter provided in the neutralization tank 1. 12 is a neutralization tank 1
It is a pipe for feeding the liquid in the coagulation tank 2 equipped with the pH meter 2A. 13 is a sedimentation tank (thickener) for the liquid in the coagulation tank 2
3 is a pipe for feeding, 3 is a drain pipe for treated water,
Reference numeral 5 denotes an extraction pipe for sludge separated in the settling tank 3, which branches into a discharge pipe 16 for sending the sludge to a dehydrator (not shown) and a return pipe 17 for returning the sludge to the alkali mixing tank 4. Reference numeral 18 denotes a pipe for supplying alkali in the alkali storage tank 5, which is branched into a supply pipe 18A for the neutralization tank 1 and a supply pipe 18B for the alkali mixing tank 4. Reference numeral 19 is a pipe for supplying a polymer (polymer flocculant) to the flocculation tank 2, and 20 is a pipe for feeding the alkaline sludge from the alkali mixing tank 4 to the neutralization tank 2.
【０００８】Ｐ1 ，Ｐ2 ，Ｐ3 はポンプであり、Ｖ1 ，
Ｖ2 ，Ｖ3 は自動弁である。また、２２は流量計、２３
は原水ＳＳ計、２４は汚泥濃度計であり、流量計２２で
測定された原水流量と原水ＳＳ計２３で測定された原水
水質と、汚泥濃度計２４で測定された汚泥濃度の各値が
演算システム１０に入力され、所定の汚泥返送比となる
ように、ポンプＰ2 の作動及び自動弁Ｖ3 の開閉を制御
するように構成されている。また、中和槽１のｐＨに応
じて、中和槽１へのアルカリ添加量及びアルカリ混合槽
４へのアルカリ添加量が制御されるように、自動弁Ｖ
1 ，Ｖ2 の開閉は、ｐＨ計１Ａの測定値に基いて制御さ
れる。P 1 , P 2 , P 3 are pumps, V 1 ,
V 2 and V 3 are automatic valves. Further, 22 is a flow meter, 23
Is a raw water SS meter, and 24 is a sludge concentration meter. The raw water flow rate measured by the flow meter 22, the raw water quality measured by the raw water SS meter 23, and the sludge concentration measured by the sludge concentration meter 24 are calculated. The operation of the pump P 2 and the opening / closing of the automatic valve V 3 are controlled so that the sludge return ratio is input to the system 10. Further, the automatic valve V is controlled so that the amount of alkali added to the neutralization tank 1 and the amount of alkali added to the alkali mixing tank 4 are controlled according to the pH of the neutralization tank 1.
The opening / closing of 1 and V 2 is controlled based on the measured value of the pH meter 1A.
【０００９】このような制御システムにおいて、導入管
１１からの原水は、中和槽１でそのｐＨ値に応じて配管
１８からのアルカリ、及び、配管２０からのアルカリ汚
泥が添加されて中和された後、配管１２より凝集槽２に
送給され、配管１９より添加されるポリマーで凝集処理
され、その後、配管１３を経て沈殿槽３に送給されて沈
降分離される。沈殿槽３で分離された上澄水は処理水と
して配管１４より系外へ排出され、一方、分離汚泥は配
管１５より抜き出され、演算システム１０で選定された
所定量はポンプＰ2 を備える配管１７より返送汚泥とし
てアルカリ混合槽４に返送され、残部は配管１６より脱
水機に送給され、脱水処理される。In such a control system, the raw water from the introduction pipe 11 is neutralized in the neutralization tank 1 by adding the alkali from the pipe 18 and the alkali sludge from the pipe 20 according to the pH value. After that, it is fed to the coagulation tank 2 through the pipe 12 and subjected to coagulation treatment with the polymer added through the pipe 19, and then fed to the settling tank 3 through the pipe 13 for sedimentation separation. The supernatant water separated in the settling tank 3 is discharged as treated water from the pipe 14 to the outside of the system, while the separated sludge is extracted from the pipe 15 and a predetermined amount selected by the arithmetic system 10 is provided with a pump P 2. The sludge is returned from 17 to the alkali mixing tank 4, and the rest is sent to the dehydrator through the pipe 16 for dehydration treatment.
【００１０】配管１７よりアルカリ混合槽４に返送され
た汚泥は、アルカリ貯槽５より配管１８，１８Ｂを経て
供給されるアルカリと反応する。即ち、汚泥表面にアル
カリが吸着される。このアルカリ吸着汚泥は配管２０よ
り中和槽１に添加される。The sludge returned to the alkali mixing tank 4 through the pipe 17 reacts with the alkali supplied from the alkali storage tank 5 through the pipes 18 and 18B. That is, alkali is adsorbed on the sludge surface. This alkali-adsorbed sludge is added to the neutralization tank 1 through the pipe 20.
【００１１】ところで、汚泥返送比を決定する因子のう
ち、原水中和時の発生ＳＳ量は、原水を中和した際に、
原水中に溶解していた金属Ｍn+が水酸化物（Ｍn+→Ｍ
（ＯＨ）n ）となり、ＳＳとして析出する量である。Among the factors that determine the sludge return ratio, the amount of SS generated during neutralization of raw water is
The metal M n + dissolved in the raw water is a hydroxide (M n + → M
(OH) n ), which is the amount deposited as SS.
【００１２】従来の方法では、原水水質、原水流量の変
動、及び、その結果変動する汚泥濃度を連続的に自動測
定し、汚泥返送比Ｒが一定となるように返送汚泥量を調
整している。In the conventional method, the fluctuation of raw water quality, the fluctuation of raw water flow rate, and the sludge concentration which fluctuates as a result are continuously and automatically measured, and the amount of sludge to be returned is adjusted so that the sludge return ratio R becomes constant. .
【００１３】なお、従来、汚泥濃度を連続的に測定する
方法としては、超音波法や近赤外線法が一般的であり、
これらの測定方法は下水処理場の汚泥管理などにも採用
されている。Conventionally, as a method for continuously measuring the sludge concentration, an ultrasonic method or a near infrared method is generally used.
These measurement methods are also used for sludge management in sewage treatment plants.
【００１４】[0014]
【発明が解決しようとする課題】従来の汚泥濃度測定方
法のうち、超音波法では、汚泥から発生するＮ2 ，ＣＯ
2 などのガス、或いは、ポンプのケーシングより混入す
る空気、圧力変化により発生する溶存空気などの影響に
より、正確な測定値が得られないという欠点がある。即
ち、例えば、汚泥濃度が５ｋｇ／ｍ3 であっても、汚泥
中に混入ガスがあると、この混入ガスは超音波を吸収す
るため、測定値としては１０〜３０ｋｇ／ｍ3 といった
結果が得られる事態が頻発する。この問題を解決するた
めに、汚泥に圧力を加え、気泡を発生させない工夫が採
用されてはいるが、十分な効果は得られていない。Among the conventional sludge concentration measuring methods, the ultrasonic method uses N 2 and CO generated from sludge.
Due to the influence of gases such as 2 or the like, air mixed in from the casing of the pump, dissolved air generated due to pressure changes, etc., there is the drawback that accurate measured values cannot be obtained. That is, for example, even if the sludge concentration is 5 kg / m 3 , if mixed gas is present in the sludge, the mixed gas absorbs ultrasonic waves, and thus a measurement value of 10 to 30 kg / m 3 is obtained. Situations often occur. In order to solve this problem, a device that does not generate bubbles by applying pressure to the sludge is adopted, but a sufficient effect has not been obtained.
【００１５】一方、近赤外線法も、汚泥発泡や濁質の色
調の影響を受け易く、しかも、センサー部の発光・受光
部の石英セルが汚染されると精度が致命的に劣化するこ
とから、セル周辺設備の保守管理が煩雑であるという欠
点がある。On the other hand, the near-infrared ray method is also easily affected by the color tone of sludge foaming and turbidity, and further, if the quartz cell of the light emitting / receiving portion of the sensor is contaminated, the accuracy is fatally deteriorated. There is a drawback that maintenance management of the equipment around the cell is complicated.
【００１６】このように、従来のアルカリ汚泥法におけ
る返送汚泥量の制御においては、汚泥濃度の正確な測定
が困難であるため、返送汚泥量の適確な制御及びこれに
よる汚泥濃度の向上が十分に行われていないのが現状で
ある。As described above, in the control of the amount of returned sludge in the conventional alkaline sludge method, it is difficult to measure the concentration of sludge accurately, so that it is necessary to appropriately control the amount of returned sludge and to improve the concentration of sludge thereby. The current situation is that it has not been conducted.
【００１７】本発明は上記従来の問題点を解決し、金属
含有排水にアルカリを添加し、生成する金属水酸化物を
含む汚泥と処理水とに固液分離し、分離した汚泥を前処
理工程に返送して金属含有排水に混合する方法におい
て、返送汚泥の濃度を簡単な設備で迅速かつ適確に求め
ることにより、返送汚泥量の制御を効果的に行って、高
濃度汚泥を得る方法を提供することを目的とする。The present invention solves the above-mentioned conventional problems, adds an alkali to metal-containing wastewater, and solid-liquid separates sludge containing metal hydroxide to be produced and treated water. The separated sludge is subjected to a pretreatment step. In the method of returning to and mixing with the metal-containing wastewater, a method to obtain a high-concentration sludge by effectively controlling the amount of returned sludge by quickly and accurately obtaining the concentration of the returned sludge with simple equipment. The purpose is to provide.
【００１８】[0018]
【課題を解決するための手段】本発明の金属含有排水の
処理方法は、金属含有排水にアルカリを添加し、生成す
る金属水酸化物を含む汚泥と処理水とに固液分離し、分
離した汚泥を前処理工程に返送して金属含有排水に混合
する方法であって、該返送汚泥の濃度に基いて前記返送
汚泥量を決定する方法において、該返送汚泥の所定高さ
の圧力を測定し、この測定値に基いて該返送汚泥の濃度
を算出することを特徴とする。In the method for treating metal-containing wastewater of the present invention, an alkali is added to the metal-containing wastewater, and the sludge containing the metal hydroxide produced is subjected to solid-liquid separation and separated. A method of returning sludge to a pretreatment step and mixing it with metal-containing wastewater, wherein in the method of determining the amount of returned sludge based on the concentration of the returned sludge, the pressure at a predetermined height of the returned sludge is measured. The concentration of the returned sludge is calculated based on the measured value.
【００１９】[0019]
【作用】図２に示す如く、上部が開放した容器３０のよ
うな開放系において、圧力計３１で測定される水頭圧Ｐ
m-H2O は、下記式で表される。As shown in FIG. 2, in an open system such as a container 30 having an open upper part, the head pressure P measured by a pressure gauge 31.
m-H2O is represented by the following formula.
【００２０】Ｐm-H2O ∝Ｈ×ｓｇ ……（１） （Ｈ：圧力測定値から解放部までの高さ ｓｇ：液比重） 一方、液比重ｓｇは、汚泥濃度Ｃの関数であり、下記式
で表される。P m-H 2 O ∝H × sg (1) (H: Height from pressure measurement value to release part sg: liquid specific gravity) On the other hand, liquid specific gravity sg is a function of sludge concentration C, and It is represented by a formula.
【００２１】Ｃ∝Ａ×ｓｇ ……（２） （Ａ：定数） 例えば、図３に、アルカリ汚泥法で改質された水酸化銅
の返送汚泥濃度と比重との関係を示すが、図３より、こ
の返送汚泥濃度Ｃと比重とは明らかに相関がある。C∝A × sg (2) (A: constant) For example, FIG. 3 shows the relationship between the return sludge concentration and the specific gravity of copper hydroxide modified by the alkaline sludge method. Therefore, there is a clear correlation between the returned sludge concentration C and the specific gravity.
【００２２】従って、上記（１）式及び（２）式より、
下記式（３）が得られる。Therefore, from the above equations (1) and (2),
The following formula (3) is obtained.
【００２３】Ｃ∝Ａ／Ｈ×Ｐm-H2O ……（３） ここで、Ｈを一定とすれば、Ａ／Ｈは定数となる。この
定数をＢとすると、上記（３）式は下記（４）式とな
る。C∝A / H × P m-H2O (3) Here, if H is constant, A / H becomes a constant. If this constant is B, the above equation (3) becomes the following equation (4).
【００２４】Ｃ＝Ｂ×Ｐm-H2O ……（４） 従って、水頭圧Ｐm-H2O を圧力センサー等により測定す
れば、簡単に汚泥濃度を求めることができる。C = B × P m-H2O (4) Therefore, if the head pressure P m-H2O is measured by a pressure sensor or the like, the sludge concentration can be easily obtained.
【００２５】圧力センサー等による圧力の測定であれ
ば、 汚泥への混入空気、発生ガスなどの影響を受けるこ
とがない。 汚泥の色調の変化に影響を受けることがない。 センサーが圧力計という単純な機構であるため故障
が少ない。 取り付け、保守管理が容易である。 といった優れた効果が奏され、工業的に極めて有利であ
る。As long as the pressure is measured by a pressure sensor or the like, there is no influence of air mixed with sludge or generated gas. Unaffected by changes in sludge color. Since the sensor is a simple mechanism called a pressure gauge, there are few failures. Easy to install and maintain. Such an excellent effect is exhibited, which is extremely advantageous industrially.
【００２６】[0026]
【実施例】以下図面を参照して本発明を詳細に説明す
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.
【００２７】図１は本発明の金属含有排水の処理方法に
おける返送汚泥の圧力測定方法の一実施例を示す構成図
であり、図５に示す制御システムの汚泥濃度計の代りに
圧力センサーを取り付けた例を示すものである。FIG. 1 is a block diagram showing an embodiment of a method for measuring the pressure of returned sludge in the method for treating metal-containing wastewater according to the present invention, in which a pressure sensor is attached instead of the sludge concentration meter of the control system shown in FIG. It shows an example.
【００２８】本実施例においては、図５の制御システム
において、沈殿槽３からアルカリ混合槽４に汚泥を返送
する配管１７に分岐配管１７Ａを設け、この分岐配管１
７Ａに取り付けた圧力センサー４０により、汚泥の圧力
を測定する。In this embodiment, in the control system of FIG. 5, a branch pipe 17A is provided in the pipe 17 for returning sludge from the settling tank 3 to the alkali mixing tank 4, and the branch pipe 1
The pressure of the sludge is measured by the pressure sensor 40 attached to 7A.
【００２９】即ち、分岐配管１７Ａは、配管１７から分
岐する水平部１７ａと、この水平部１７ａから立ち上げ
られた鉛直部１７ｂと、鉛直部１７ｂからアルカリ混合
槽４の上方に延びる水平部１７ｃとで構成され、鉛直部
１７ｂの上部には開放部１７ｄが設けられた開放配管で
あり、鉛直部１７ｂの下部に圧力センサー４０が取り付
けられ、高さＨに相当する配管内部の汚泥の圧力を測定
するように構成されている。That is, the branch pipe 17A has a horizontal portion 17a branched from the pipe 17, a vertical portion 17b raised from the horizontal portion 17a, and a horizontal portion 17c extending from the vertical portion 17b to above the alkali mixing tank 4. It is an open pipe having an open part 17d provided on the upper part of the vertical part 17b, a pressure sensor 40 is attached to the lower part of the vertical part 17b, and the pressure of sludge inside the pipe corresponding to the height H is measured. Is configured to.
【００３０】この圧力センサー４０は、検知した圧力を
電流値に変換して、或いは、直読の圧力値として表示す
る機能を有し、この測定値は、図５に示す、演算システ
ム１０に入力される。The pressure sensor 40 has a function of converting the detected pressure into a current value or displaying it as a direct reading pressure value, and the measured value is inputted to the arithmetic system 10 shown in FIG. It
【００３１】演算システム１０においては、前述の
（４）式より、予め求めた定数を用いて汚泥濃度を算出
し、この算出値と、流量計２２の測定値及び原水ＳＳ計
２３の測定値とから、所定の汚泥返送比Ｒの範囲内とな
るように返送汚泥量を算出し、前述の従来法と同様にポ
ンプＰ2 及び自動弁Ｖ3 の制御信号を出力する。In the arithmetic system 10, the sludge concentration is calculated from the above-mentioned equation (4) using a constant previously obtained, and the calculated value, the measured value of the flowmeter 22 and the measured value of the raw water SS meter 23 are calculated. Then, the amount of sludge to be returned is calculated so that it falls within the range of the predetermined sludge return ratio R, and the control signals for the pump P 2 and the automatic valve V 3 are output as in the above-mentioned conventional method.
【００３２】なお、汚泥の圧力の測定は、任意の測定サ
イクルのバッチ方式で行う。即ち、汚泥が流動している
条件下では、圧力の測定値が一定しないため、汚泥を配
管１７Ａ内に滞留させた状態で圧力の測定を行う。The sludge pressure is measured by a batch method with an arbitrary measurement cycle. That is, since the measured pressure value is not constant under the condition that the sludge is flowing, the pressure is measured while the sludge is retained in the pipe 17A.
【００３３】具体的には、自動弁Ｖ4 を閉，自動弁Ｖ3
を開として汚泥を配管１７Ａからアルカリ混合槽４に返
送している状態から、圧力測定に際しては、自動弁Ｖ4
を開，自動弁Ｖ3 を閉として、配管１７Ａから汚泥を返
送するようにする。圧力の測定に要する配管１７Ａ内の
汚泥の滞留時間は約１０〜６０秒程度であるから、一般
には、２〜３分間配管１７を経て汚泥の返送を行った
後、自動弁を切り換えて配管１７Ａに汚泥を送り、圧力
測定を行い、その後、配管１７Ａ内の汚泥をアルカリ混
合槽４に投入する。この自動弁の切り換え、圧力測定に
要する時間は約５分程度であるため、一般には、圧力の
測定サイクルを５分以上の間隔に設定し、間欠測定を行
う。Specifically, the automatic valve V 4 is closed and the automatic valve V 3 is
When the pressure is measured from the state where the sludge is opened and the sludge is returned to the alkali mixing tank 4 from the pipe 17A, the automatic valve V 4
Is opened and the automatic valve V 3 is closed to return the sludge from the pipe 17A. The sludge residence time in the pipe 17A required for pressure measurement is about 10 to 60 seconds, so generally, after returning the sludge through the pipe 17 for 2 to 3 minutes, the automatic valve is switched to change the pipe 17A. The sludge is sent to, the pressure is measured, and then the sludge in the pipe 17A is put into the alkali mixing tank 4. Since the time required for this automatic valve switching and pressure measurement is about 5 minutes, the pressure measurement cycle is generally set at intervals of 5 minutes or more, and intermittent measurement is performed.
【００３４】なお、汚泥の圧力の測定を行う配管１７Ａ
の鉛直部１７ｂの高さＨは高いほど圧力の測定誤差が少
なく、汚泥濃度を正確に求めることができるが、通常の
場合、２ｍ以上あれば十分である。The pipe 17A for measuring the sludge pressure
As the height H of the vertical portion 17b is higher, the pressure measurement error is smaller and the sludge concentration can be accurately obtained, but in the normal case, 2 m or more is sufficient.
【００３５】以下に具体的な実施例を挙げて、本発明を
より詳細に説明する。The present invention will be described in more detail with reference to specific examples.
【００３６】実施例１ 図５に示す制御システムにおいて、汚泥濃度計の代りに
図１に示す圧力センサーを取り付け、下記水質の金属含
有排水を原水として処理を行った。Example 1 In the control system shown in FIG. 5, the pressure sensor shown in FIG. 1 was attached instead of the sludge concentration meter, and the wastewater containing metal having the following water quality was treated as raw water.
【００３７】原水水質 ｐＨ：２〜３ Ｃｕ：２００〜４００ｐｐｍ Ｚｎ：２０〜３０ｐｐｍ Ｃｒ：１〜３ｐｐｍ なお、圧力センサーを取り付けた鉛直部の高さ（Ｈ）は
３．５ｍとし、水頭圧を４〜２０ｍＡの電流値の汚泥濃
度に変換して、演算システムを作動させた。 Raw water quality pH: 2 to 3 Cu: 200 to 400 ppm Zn: 20 to 30 ppm Cr: 1 to 3 ppm The height (H) of the vertical portion to which the pressure sensor is attached is 3.5 m, and the head pressure is 4. It converted into the sludge density | concentration of a current value of -20 mA, and operated the arithmetic system.
【００３８】ここで得られた汚泥濃度と汚泥の水頭圧と
の関係は図４の通りであり、この図４より、汚泥濃度は
圧力測定により容易に検知できることが明らかである。The relationship between the sludge concentration and the head pressure of sludge obtained here is as shown in FIG. 4, and it is clear from this FIG. 4 that the sludge concentration can be easily detected by pressure measurement.
【００３９】この圧力測定により求めた汚泥濃度と、原
水ＳＳ計及び流量計の測定値に基いて、汚泥返送比Ｒが
３０〜４０となるように返送汚泥量を制御して処理を行
ったところ、得られた汚泥濃度は２５〜３２％であり、
従来の中和汚泥濃度２〜３％に比べて、汚泥濃度は格段
に高められ、返送汚泥量の制御運転に、圧力センサーを
有効に適用可能であることが確認された。Based on the sludge concentration obtained by this pressure measurement and the measured values of the raw water SS meter and the flow meter, the amount of the returned sludge was controlled so that the sludge return ratio R was 30 to 40. , The obtained sludge concentration is 25-32%,
It was confirmed that the sludge concentration was significantly increased compared to the conventional neutralized sludge concentration of 2 to 3%, and that the pressure sensor can be effectively applied to the control operation of the amount of returned sludge.
【００４０】[0040]
【発明の効果】以上詳述した通り、本発明の金属含有排
水の処理方法によれば、金属含有排水にアルカリを添加
し、生成する金属水酸化物を含む汚泥と処理水とに固液
分離し、分離した汚泥を前処理工程に返送して金属含有
排水に混合する方法であって、該返送汚泥の濃度に基い
て前記返送汚泥量を決定する方法において、返送汚泥の
圧力を測定することにより、返送汚泥濃度を簡単な設備
で容易かつ迅速にしかも正確に求めることができる。こ
のため、高濃度汚泥を得るために必要な返送汚泥量の制
御を確実に行って、高濃度汚泥及び高水質処理水を効率
的に得ることが可能とされる。As described in detail above, according to the method for treating metal-containing wastewater of the present invention, an alkali is added to the metal-containing wastewater, and solid-liquid separation is performed between sludge containing metal hydroxide produced and treated water. In the method of returning the separated sludge to the pretreatment step and mixing it with the metal-containing wastewater, in the method of determining the amount of the returned sludge based on the concentration of the returned sludge, measuring the pressure of the returned sludge. This makes it possible to obtain the returned sludge concentration easily, quickly and accurately with simple equipment. Therefore, it is possible to reliably control the amount of returned sludge necessary to obtain high-concentration sludge and efficiently obtain high-concentration sludge and high-quality treated water.
【図１】本発明の金属含有排水の処理方法における返送
汚泥の圧力測定方法の一実施例を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of a method for measuring the pressure of returned sludge in the method for treating metal-containing wastewater according to the present invention.
【図２】開放系の水頭圧を示す断面図である。FIG. 2 is a cross-sectional view showing the hydraulic head pressure of an open system.
【図３】汚泥濃度と比重との関係を示すグラフである。FIG. 3 is a graph showing the relationship between sludge concentration and specific gravity.
【図４】汚泥濃度と圧力との関係を示すグラフである。FIG. 4 is a graph showing the relationship between sludge concentration and pressure.
【図５】アルカリ汚泥法における返送汚泥量の制御シス
テムを示す系統図である。FIG. 5 is a system diagram showing a control system for returning sludge amount in the alkaline sludge method.
１ 中和槽 ２ 凝集槽 ３ 沈殿槽 ４ アルカリ混合槽 ５ アルカリ貯槽 １０ 演算システム ４０ 圧力センサー 1 Neutralization tank 2 Coagulation tank 3 Precipitation tank 4 Alkali mixing tank 5 Alkali storage tank 10 Calculation system 40 Pressure sensor
Claims (1)
する金属水酸化物を含む汚泥と処理水とに固液分離し、
分離した汚泥を前処理工程に返送して金属含有排水に混
合する方法であって、該返送汚泥の濃度に基いて前記返
送汚泥量を決定する方法において、 該返送汚泥の所定高さの圧力を測定し、この測定値に基
いて該返送汚泥の濃度を算出することを特徴とする金属
含有排水の処理方法。1. An alkali is added to the metal-containing wastewater to perform solid-liquid separation into sludge containing the metal hydroxide produced and treated water,
A method of returning the separated sludge to a pretreatment step and mixing it with the metal-containing wastewater, wherein in the method of determining the amount of the returned sludge based on the concentration of the returned sludge, the pressure of the predetermined height of the returned sludge is adjusted. A method for treating metal-containing wastewater, which comprises measuring and calculating the concentration of the returned sludge based on the measured value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26967794A JP3567506B2 (en) | 1994-11-02 | 1994-11-02 | Treatment method for metal-containing wastewater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26967794A JP3567506B2 (en) | 1994-11-02 | 1994-11-02 | Treatment method for metal-containing wastewater |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08132069A true JPH08132069A (en) | 1996-05-28 |
| JP3567506B2 JP3567506B2 (en) | 2004-09-22 |
Family
ID=17475662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26967794A Expired - Lifetime JP3567506B2 (en) | 1994-11-02 | 1994-11-02 | Treatment method for metal-containing wastewater |
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| Country | Link |
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| JP (1) | JP3567506B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023089926A1 (en) * | 2021-11-19 | 2023-05-25 | 栗田工業株式会社 | Waste water treatment method |
-
1994
- 1994-11-02 JP JP26967794A patent/JP3567506B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023089926A1 (en) * | 2021-11-19 | 2023-05-25 | 栗田工業株式会社 | Waste water treatment method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3567506B2 (en) | 2004-09-22 |
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