JP4095147B2

JP4095147B2 - Water purification method

Info

Publication number: JP4095147B2
Application number: JP01081698A
Authority: JP
Inventors: 辰彦鈴木
Original assignee: Maezawa Industries Inc
Current assignee: Maezawa Industries Inc
Priority date: 1998-01-22
Filing date: 1998-01-22
Publication date: 2008-06-04
Anticipated expiration: 2018-01-22
Also published as: JPH11207378A

Description

【０００１】
【発明の属する技術分野】
本発明は、膜分離を用いた浄水処理方法に関し、詳しくは、膜分離装置を用いて上水，下水，排水等を浄化処理する設備等において、原水中に含まれる固体成分だけでなく、溶解性有機物や溶解性マンガン（以下、マンガンという）等の金属成分も同時に除去するための方法に関する。
【０００２】
【従来の技術】
例えば、上水の処理設備において、原水中に含まれる固体成分（固形物やフロック等の懸濁成分）を分離除去するため、膜分離装置を用いて固液分離することが行われている。一方、原水中に金属成分、例えばマンガンが含まれている場合は、マンガンを除去するために、濾過処理設備の前段に除マンガン設備を設けている。この除マンガン設備としては、一般に、マンガン砂をろ材とする接触濾過法が用いられているが、濾過処理設備とは別に除マンガン設備を設置しなければならないため、スペース的な問題が発生するとともに、設備費にも大きな影響を与えることになる。また、鉄等の他の金属の場合も同様な設備を設置する必要がある。
【０００３】
さらに、原水中に含まれる溶解性有機物の除去には、活性炭吸着が一般に行われており、これらの固液分離、金属成分除去、溶解性有機物の除去を全て行うためには、これらの処理設備をそれぞれ設けなければならなかった。
【０００４】
このようなことから、膜分離装置の前段に接触槽を設け、原水中に粉末活性炭を投入して溶解性有機物を吸着除去するとともに、膜分離装置内の固体成分を接触槽に返送し、固体成分に付着した微生物により原水中の溶解性有機物及びマンガン等の金属成分を除去する方法が提案されている。
【０００５】
【発明が解決しようとする課題】
上記方法によれば、一つの設備で原水中の固体成分と同時に金属成分や溶解性有機物も除去することができるので、処理設備の簡略化が図れるが、粉末活性炭を含む原水を膜分離装置の上部から流入させると、膜分離手段を形成する中空糸膜モジュールの端部に粉末活性炭が詰まり、これによって空洗時における中空糸等の揺らぎが小さくなることにより、徐々に中空糸膜の全体に粉末活性炭の詰まりが進行し、ついには、膜の運転を行えなくなることがある。この現象は、膜分離手段の側方から原水を流入させた場合でも、程度の差はあるものの同様である。一方、粉末活性炭を含む原水を膜分離手段より下方に流入させると、粉末活性炭を槽全体に十分に拡散することができず、粉末活性炭による吸着除去効率が大幅に低下することになる。
【０００６】
そこで本発明は、粉末活性炭等の吸着材を含む原水を、膜分離装置の適当な位置に流入させることにより、吸着材による吸着除去効率を向上できるとともに、膜分離手段による固液分離効率も向上させることができる浄水処理方法を提供することを目的としている。
【０００７】
【課題を解決するための手段】
上記目的を達成するため、本発明の浄水処理方法は、原水中の固体成分を分離する膜分離手段の下方に散気手段を配置した膜分離装置と、該膜分離装置の前段に設けた接触槽とを有し、該接触槽にて原水中に吸着材を投入するとともに、前記膜分離装置で分離した固体成分を前記接触槽に返送して原水と混合し、固体成分に付着した微生物の作用と前記吸着材の吸着作用とにより、原水中の溶解性有機物及び金属成分を除去する浄水処理方法であって、前記膜分離装置への原水の流入管の接続位置を、前記膜分離手段の下端と散気手段との間に設定し、前記吸着材を含む原水を、前記膜分離装置の膜分離手段の下端と散気手段との間から膜分離装置内に流入させることを特徴としている。
【０００８】
【発明の実施の形態】
図１は、本発明の浄水処理方法の一形態例を示す系統図であって、膜分離装置１０と、その前段に設けられた接触槽２０とにより形成されている。膜分離装置１０は、原水中に含まれる固体成分を分離除去する膜分離手段１１と、この膜分離手段１１の下方に設置された散気手段１２とを有する処理槽１３に、接触槽２０からの原水が流入する流入管１４と、槽底部に沈殿する固体成分を接触槽２０に返送するための返送管１５とを設けたもので、膜分離手段１１には、固体成分を分離した処理水を後段の処理水槽等に送るための流出管１６が設けられている。
【０００９】
接触槽２０は、原水が流入する原水流入管２１と、膜分離装置１０から返送される固体成分（汚泥）が流入する前記返送管１５と、粉末活性炭等の吸着材を投入するための吸着材投入手段２２と、原水と固体成分（吸着材を含む）とを撹拌混合するための撹拌機２３と、撹拌混合後の水を膜分離装置１０に送る前記流入管１４とが設けられている。
【００１０】
なお、膜分離手段１１は、従来からこの種の処理に用いられている中空糸膜等を用いた各種膜分離手段を用いることが可能であり、膜の種類も特に限定されるものではなく、原水の状態に応じて、ＭＦ膜やＵＦ膜あるいは適宜なメッシュの網状体を適宜選択して使用することができる。さらに、吸着材の種類も、原水の状態に応じて適当なものを選択することができるが、通常は、粉末活性炭を用いることが好ましい。
【００１１】
原水は、原水流入管２１から接触槽２０内に流入してモーターＭで駆動される撹拌機２３により撹拌され、膜分離装置１０の底部から返送管１５に抜出されてポンプＰにより圧送されてきた固体成分及び吸着材投入手段２２から投入された吸着材と混合する。固体成分と混合した原水は、流入管１４から膜分離装置１０の処理槽１３内に流入し、膜分離手段による固液分離と、吸着材による溶解性有機物の吸着除去等の浄化処理が行われる。
【００１２】
ここで、前記処理槽１３における流入管１４の接続位置は、前記膜分離手段１１の下端１１ａと散気手段１２との間に設定されており、接触槽２０から流入管１４を経て膜分離装置１０に供給される吸着材及び固体成分を含む原水を、膜分離手段１１の下端１１ａと散気手段１２との間に流入させるようにしている。このとき、膜分離手段１１の下端１１ａと散気手段１２との間の距離Ａは、膜分離装置１０の処理量や膜の種類、槽底部に沈降する固体成分の量等に応じて適当な距離に設定されるものであり、通常は、３５０〜４００ｍｍ程度が適当であるが、それ以上であっても構わない。そして、膜分離手段１１の下端１１ａと流入管１４の接続位置との間の距離Ｂは、前記距離Ａが３５０〜４００ｍｍの場合は、１５０〜２００ｍｍ程度が好ましいが、それ以上であっても、散気手段１２より上方にあればよい。
【００１３】
すなわち、原水に含まれる吸着材が膜分離手段１１に直接当たるような位置に原水を流入させると膜分離手段１１の詰まりが発生しやすく、逆に、散気手段１２より下方に原水を流入させると、散気手段１２から散気を行っても吸着材や固体成分を処理槽１３の全体に十分に拡散することができず、いずれの場合も処理効率が低下するが、上述のように、膜分離手段１１の下端１１ａと散気手段１２との間に原水を流入させることにより、膜分離手段１１の詰まりを抑制できるとともに、散気手段１２からの散気によって吸着材や固体成分を処理槽１３の全体に十分に拡散させることができ、溶解性有機物や金属成分の除去効率を向上させることができる。
【００１４】
なお、散気手段１２からの散気は、連続的に行ってもよく、間欠的に行ってもよく、さらに、散気量を変化させるようにしてもよい。また、吸着材に、溶解性有機物や金属成分を分解する微生物をあらかじめ付着させておいてもよい。
【００１５】
処理槽１３内において、固体成分に付着した微生物の作用及び吸着材の吸着作用により溶解性有機物及び金属成分の除去が行われた後、膜分離手段１１により固液分離が行われ、水に不溶性の固体成分が水から分離して処理槽１３の底部に沈殿する。
【００１６】
処理槽１３の底部に沈殿した吸着材を含む固体成分は、搬送用の所定量の水と共に返送管１５に抜出され、ポンプＰを介して接触槽２０内に循環する。一方、溶解性有機物及び金属成分が除去され、膜分離手段１１で固体成分から分離した処理水は、ポンプＰによって流出管１６に抜き出され、処理水槽等に送られる。
【００１７】
このように、膜分離装置１０の前段に接触槽２０を設け、膜分離装置１０から抜出した汚泥を接触槽２０に返送して原水と混合するとともに、原水中に吸着材を投入して浄水処理を行うにあたり、吸着材を含む原水を、膜分離手段１１の下端１１ａと散気手段１２との間から膜分離装置１０内に流入させることにより、膜分離装置１０における膜分離手段１１の詰まりを抑えることができるとともに、吸着材や固体成分を原水中に十分に拡散させることができるので、溶解性有機物及び溶解性金属成分の分解除去や吸着除去を効率よく行うことができ、膜分離による固体成分の分離除去と、金属成分及び溶解性有機物の除去とを同時に行うことができる。
【００１８】
しかも、吸着材の投入量を適当に設定することにより、返送管１５から接触槽２０に返送される汚泥（固体成分）中の微生物の密度を適度に高めることができるので、生物学的除去効率が向上するとともに、膜分離手段１１の詰まりの原因となる微小有機物を吸着材に吸着させることができるので、膜の詰まりの発生を抑えることもできる。
【００１９】
なお、吸着材は、連続的に投入してもよいが、通常は、汚泥量等の運転状態に応じてバッチ方式で適当量を投入すればよく、投入位置も任意に選択することができる。特に、微生物の活性が低下する低水温時に吸着材を投入することにより、多くの微生物を吸着材に付着させることができるので、低水温時においても通常時と変らぬ処理効率が得られる。
【００２０】
【発明の効果】
以上説明したように、本発明の浄水処理方法によれば、簡単な装置構成の設備で金属成分，溶解性有機物及び固体成分を効率よく除去することができる。
【図面の簡単な説明】
【図１】本発明方法の一形態例を示す系統図である。
【符号の説明】
１０…膜分離装置、１１…膜分離手段、１２…散気手段、１３…処理槽、１４…流入管、１５…返送管、１６…流出管、２０…接触槽、２１…原水流入管、２２…粉末活性炭投入手段、２３…撹拌機、Ａ…膜分離手段の下端と散気手段との間の距離、Ｂ…膜分離手段の下端と流入管の接続位置との間の距離[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water purification method using membrane separation. Specifically, in a facility for purifying water, sewage, waste water, etc. using a membrane separator, not only solid components contained in raw water but also dissolved The present invention relates to a method for simultaneously removing metallic components such as soluble organic matter and soluble manganese (hereinafter referred to as manganese).
[0002]
[Prior art]
For example, in a treatment facility for clean water, solid-liquid separation is performed using a membrane separation device in order to separate and remove solid components (solid components, suspended components such as floc) contained in raw water. On the other hand, when a metal component such as manganese is contained in the raw water, a manganese removal facility is provided in front of the filtration treatment facility in order to remove manganese. As this manganese removal equipment, generally, a contact filtration method using manganese sand as a filter medium is used. However, since a manganese removal equipment must be installed separately from the filtration treatment equipment, a space problem occurs. The equipment cost will be greatly affected. In the case of other metals such as iron, it is necessary to install similar equipment.
[0003]
Furthermore, activated carbon adsorption is generally performed to remove soluble organic substances contained in raw water, and in order to perform all of these solid-liquid separation, metal component removal, and soluble organic substance removal, these treatment facilities are used. Each had to be established.
[0004]
For this reason, a contact tank is provided in the previous stage of the membrane separator, and powdered activated carbon is introduced into the raw water to adsorb and remove soluble organic substances, and the solid components in the membrane separator are returned to the contact tank. A method has been proposed in which soluble organic substances in raw water and metal components such as manganese are removed by microorganisms adhering to the components.
[0005]
[Problems to be solved by the invention]
According to the above method, since the metal component and soluble organic matter can be removed simultaneously with the solid component in the raw water with one facility, the treatment facility can be simplified, but the raw water containing the powdered activated carbon is removed from the membrane separation device. When flowing from the top, powdered activated carbon is clogged at the end of the hollow fiber membrane module forming the membrane separation means, and this reduces the fluctuations of the hollow fiber and the like during air washing, so that the entire hollow fiber membrane is gradually The clogging of the powdered activated carbon proceeds, and eventually the membrane may not be operated. This phenomenon is the same although there is a difference in degree even when raw water is introduced from the side of the membrane separation means. On the other hand, when raw water containing powdered activated carbon is allowed to flow downward from the membrane separation means, the powdered activated carbon cannot be sufficiently diffused throughout the tank, and the adsorption removal efficiency by the powdered activated carbon is greatly reduced.
[0006]
Therefore, in the present invention, by introducing raw water containing an adsorbent such as powdered activated carbon into an appropriate position of the membrane separation device, the adsorption removal efficiency by the adsorbent can be improved and the solid-liquid separation efficiency by the membrane separation means can also be improved. It aims at providing the water purification method which can be made to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the water purification method of the present invention comprises a membrane separation device in which an aeration means is disposed below a membrane separation means for separating solid components in raw water, and a contact provided in the previous stage of the membrane separation device. A tank, and the adsorbent is introduced into the raw water in the contact tank , and the solid component separated by the membrane separator is returned to the contact tank and mixed with the raw water so that the microorganisms adhered to the solid component The water purification method removes soluble organic substances and metal components in raw water by the action and the adsorption action of the adsorbent, wherein the connection position of the inflow pipe of the raw water to the membrane separation device is the position of the membrane separation means. It is set between a lower end and an air diffuser, and raw water containing the adsorbent is introduced into the membrane separator from between the lower end of the membrane separator and the air diffuser in the membrane separator. .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a system diagram showing an embodiment of the water purification method of the present invention, which is formed by a membrane separation device 10 and a contact tank 20 provided in the preceding stage. The membrane separation device 10 is supplied from a contact tank 20 to a treatment tank 13 having a membrane separation means 11 for separating and removing solid components contained in raw water and an aeration means 12 installed below the membrane separation means 11. Provided with an inflow pipe 14 into which raw water flows in and a return pipe 15 for returning the solid component precipitated at the bottom of the tank to the contact tank 20. The membrane separation means 11 includes treated water from which the solid component has been separated. Is provided to the downstream treated water tank or the like.
[0009]
The contact tank 20 includes a raw water inflow pipe 21 into which raw water flows, the return pipe 15 into which a solid component (sludge) returned from the membrane separation apparatus 10 flows, and an adsorbent for introducing an adsorbent such as powdered activated carbon. A charging means 22, a stirrer 23 for stirring and mixing the raw water and the solid component (including the adsorbent), and the inflow pipe 14 for sending the water after stirring and mixing to the membrane separation device 10 are provided.
[0010]
The membrane separation means 11 can use various membrane separation means using a hollow fiber membrane or the like conventionally used for this type of treatment, and the type of membrane is not particularly limited, Depending on the state of the raw water, an MF membrane, a UF membrane, or an appropriate mesh network can be appropriately selected and used. Furthermore, as the kind of adsorbent, an appropriate one can be selected according to the state of the raw water, but it is usually preferable to use powdered activated carbon.
[0011]
The raw water flows into the contact tank 20 from the raw water inflow pipe 21 and is stirred by the stirrer 23 driven by the motor M. The raw water is extracted from the bottom of the membrane separation apparatus 10 to the return pipe 15 and pumped by the pump P. The adsorbent introduced from the solid component and adsorbent input means 22 is mixed. The raw water mixed with the solid component flows into the treatment tank 13 of the membrane separation apparatus 10 from the inflow pipe 14 and is subjected to purification treatment such as solid-liquid separation by the membrane separation means and adsorption removal of soluble organic substances by the adsorbent. .
[0012]
Here, the connection position of the inflow pipe 14 in the treatment tank 13 is set between the lower end 11a of the membrane separation means 11 and the air diffusion means 12, and the membrane separation apparatus passes through the inflow pipe 14 from the contact tank 20. The raw water containing the adsorbent and the solid component supplied to 10 is allowed to flow between the lower end 11 a of the membrane separation means 11 and the aeration means 12. At this time, the distance A between the lower end 11a of the membrane separation means 11 and the aeration means 12 is appropriate depending on the amount of the membrane separation device 10 processed, the type of membrane, the amount of solid components settled on the bottom of the tank, and the like. The distance is set. Usually, about 350 to 400 mm is appropriate, but it may be longer. And the distance B between the lower end 11a of the membrane separation means 11 and the connection position of the inflow pipe 14 is preferably about 150 to 200 mm when the distance A is 350 to 400 mm, What is necessary is just to exist above the air diffuser 12.
[0013]
That is, if the raw water is caused to flow into a position where the adsorbent contained in the raw water directly hits the membrane separation means 11, the membrane separation means 11 is likely to be clogged, and conversely, the raw water is caused to flow downward from the aeration means 12. And even if air is diffused from the air diffuser 12, the adsorbent and solid components cannot be sufficiently diffused throughout the treatment tank 13, and in either case, the treatment efficiency is reduced. By allowing raw water to flow between the lower end 11a of the membrane separation means 11 and the aeration means 12, clogging of the membrane separation means 11 can be suppressed, and adsorbents and solid components are treated by the aeration from the aeration means 12. It can be sufficiently diffused in the entire tank 13, and the removal efficiency of soluble organic substances and metal components can be improved.
[0014]
The aeration from the aeration means 12 may be performed continuously, intermittently, or the amount of aeration may be changed. Further, microorganisms that decompose soluble organic substances and metal components may be attached in advance to the adsorbent.
[0015]
In the treatment tank 13, after removal of soluble organic substances and metal components by the action of microorganisms adhering to the solid component and the adsorption action of the adsorbent, solid-liquid separation is carried out by the membrane separation means 11, which is insoluble in water. The solid component is separated from the water and precipitated at the bottom of the treatment tank 13.
[0016]
The solid component containing the adsorbent deposited on the bottom of the treatment tank 13 is extracted into the return pipe 15 together with a predetermined amount of water for conveyance, and circulates in the contact tank 20 via the pump P. On the other hand, the treated organic water and the metal component are removed, and the treated water separated from the solid component by the membrane separation means 11 is extracted to the outflow pipe 16 by the pump P and sent to the treated water tank or the like.
[0017]
As described above, the contact tank 20 is provided in the front stage of the membrane separation apparatus 10, and the sludge extracted from the membrane separation apparatus 10 is returned to the contact tank 20 and mixed with the raw water, and the adsorbent is introduced into the raw water to perform the water purification treatment. When the raw material water containing the adsorbent is introduced into the membrane separator 10 from between the lower end 11a of the membrane separator 11 and the air diffuser 12, the membrane separator 11 in the membrane separator 10 is clogged. In addition to being able to suppress, the adsorbent and solid components can be sufficiently diffused in the raw water, so that it is possible to efficiently decompose and remove soluble organic substances and soluble metal components, and solid separation by membrane separation. The separation and removal of components and the removal of metal components and soluble organic substances can be performed simultaneously.
[0018]
Moreover, since the density of microorganisms in the sludge (solid component) returned from the return pipe 15 to the contact tank 20 can be appropriately increased by appropriately setting the input amount of the adsorbent, the biological removal efficiency In addition, since minute organic substances that cause clogging of the membrane separation means 11 can be adsorbed to the adsorbent, the occurrence of clogging of the membrane can be suppressed.
[0019]
The adsorbent may be continuously added, but normally, an appropriate amount may be charged in a batch system according to the operating state such as the amount of sludge, and the charging position can be arbitrarily selected. In particular, by introducing an adsorbent at a low water temperature at which the activity of microorganisms is reduced, a large number of microorganisms can be attached to the adsorbent, so that a treatment efficiency that is the same as that at normal times can be obtained even at a low water temperature.
[0020]
【The invention's effect】
As described above, according to the water purification method of the present invention, metal components, soluble organic substances, and solid components can be efficiently removed with equipment having a simple apparatus configuration.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an example of a method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Membrane separation apparatus, 11 ... Membrane separation means, 12 ... Aeration means, 13 ... Treatment tank, 14 ... Inflow pipe, 15 ... Return pipe, 16 ... Outflow pipe, 20 ... Contact tank, 21 ... Raw water inflow pipe, 22 ... powder activated carbon charging means, 23 ... stirrer, A ... distance between the lower end of the membrane separation means and the aeration means, B ... distance between the lower end of the membrane separation means and the connection position of the inflow pipe

Claims

It has a membrane separation device in which a diffuser is disposed below the membrane separation means for separating solid components in the raw water, and a contact tank provided in the front stage of the membrane separation device, and is adsorbed in the raw water in the contact tank The solid component separated by the membrane separator is returned to the contact tank and mixed with the raw water, and dissolved in the raw water by the action of microorganisms adhering to the solid component and the adsorbing action of the adsorbent. A water purification treatment method for removing volatile organic substances and metal components, wherein a connection position of an inflow pipe of raw water to the membrane separation device is set between a lower end of the membrane separation means and an aeration means, and the adsorbent A raw water treatment method is characterized in that raw water containing water is allowed to flow into the membrane separator from between the lower end of the membrane separator and the diffuser in the membrane separator.