JP2006272218A - Two-stage membrane filtration system and operation method of two-stage membrane filtration system - Google Patents

Two-stage membrane filtration system and operation method of two-stage membrane filtration system Download PDF

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JP2006272218A
JP2006272218A JP2005097269A JP2005097269A JP2006272218A JP 2006272218 A JP2006272218 A JP 2006272218A JP 2005097269 A JP2005097269 A JP 2005097269A JP 2005097269 A JP2005097269 A JP 2005097269A JP 2006272218 A JP2006272218 A JP 2006272218A
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membrane filtration
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filtration
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JP2006272218A5 (en
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Shinichi Minegishi
進一 峯岸
Ryota Takagi
亮太 高木
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Toray Industries Inc
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    • YGENERAL 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
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for improving the permeated water recovery rate of the entire water treatment system from the aspects of lowering environmental loads, lowering costs and saving energy, designing a two-stage membrane filtration plant suitable for the quality of water to be treated and stably performing operation, maintenance and management. <P>SOLUTION: For the two-stage membrane filtration system satisfying a prescribed relational expression and its operation method, the operation method comprises: a first stage filtration process of executing the membrane filtration of the water to be treated of average turbidity T<SB>1</SB>by a membrane filtration flux F<SB>1</SB>and the permeated water recovery rate R<SB>1</SB>in a first stage membrane filtration device composed of an ultrafiltration membrane module or a microfiltration membrane module; a physical cleaning process having a process of reversely washing the first stage membrane filtration device by feeding water from the permeated water side of the first stage membrane filtration device to the side of the water to be treated; and a second stage filtration process of executing the membrane filtration of physical washing drainage of average turbidity T<SB>2</SB>discharged from the first stage membrane filtration device at the time of performing the physical washing process by the membrane filtration flux F<SB>2</SB>and the permeated water recovery rate R<SB>2</SB>in a second stage membrane filtration device composed of an ultrafiltration membrane or a microfiltration membrane. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、飲料水製造のための浄水処理、工業用水製造、下水・排水処理、海水淡水化の前処理などの水処理分野において、透過水の回収率を高めた高効率で低コストな限外ろ過膜モジュールまたは精密ろ過膜モジュールからなる二段膜ろ過システム、ならびに二段膜ろ過システムの運転方法に関する。   The present invention provides a highly efficient and low-cost limit for improving the permeate recovery rate in water treatment fields such as water purification for drinking water production, industrial water production, sewage / drainage treatment, and pretreatment for seawater desalination. The present invention relates to a two-stage membrane filtration system including an outer filtration membrane module or a microfiltration membrane module, and an operation method of the two-stage membrane filtration system.

近年、膜ろ過法は飲料水製造のための浄水処理、工業用水製造、食品工業分野、下水・排水処理、海水淡水化などの様々な水処理分野での利用が進んでいる。これは、膜ろ過法が高精度の分離機能を有すること、設備の自動運転が可能で運転維持管理が容易であること、設置スペースが小さくてすむこと、既存のプロセスなど他機能のプロセスとの組合せが可能で高機能な水処理システムが組めることなどの特長を有するためである。   In recent years, membrane filtration has been used in various water treatment fields such as water purification for drinking water production, industrial water production, food industry, sewage / drainage treatment, and seawater desalination. This is because the membrane filtration method has a high-precision separation function, automatic operation of the equipment is possible, operation maintenance management is easy, installation space is small, and other processes such as existing processes This is because the water treatment system can be combined and has a high-performance water treatment system.

特に飲料水製造分野、すなわち浄水処理用途においては、家畜の糞尿などに由来するクリプトスポリジウムやジアルジアなどの耐塩素性病原性微生物が浄水場で処理しきれず、処理水に混入する事故が1990年代から顕在化していることから、従来の凝集沈殿と砂ろ過を基本とする急速ろ過法の代替として、膜ろ過法の導入が進んでいる。   Especially in the field of drinking water production, that is, water purification treatment, since the 1990s, chlorine-resistant pathogenic microorganisms such as Cryptosporidium and Giardia derived from livestock manure cannot be treated at the water purification plant and have been mixed into the treated water since the 1990s. Since it has become apparent, membrane filtration has been introduced as an alternative to conventional rapid filtration methods based on coagulation sedimentation and sand filtration.

一方、精密ろ過膜や限外ろ過膜には、細孔と呼ばれる小さな無数の孔が空いており、基本的にはこの孔より大きい物質が膜によって取り除かれ清澄な透過水が得られると共に、取り除かれた汚れ物質が膜に蓄積して“ファウリング”と呼ばれるろ過性能低下現象を引き起こす。精密ろ過膜や限外ろ過膜では、通常数十分から数時間毎に清澄水による逆流洗浄(以下逆洗と呼ぶ)や空気を用いたエアースクラビング洗浄と呼ばれる物理的な洗浄を繰り返しながらろ過運転を安定に継続させる。この物理洗浄によって膜から剥離した汚れ物質は、物理洗浄排水として膜モジュール系外に排出される。以上のような物理洗浄によってろ過運転が継続できるものの、物理洗浄に透過水の一部を使うために水処理システム全体の透過水回収率が低下するといった問題があった。   On the other hand, microfiltration membranes and ultrafiltration membranes have innumerable small pores called pores. Basically, substances larger than these pores are removed by the membrane, and clear permeated water is obtained and removed. The contaminated material accumulates on the membrane, causing a phenomenon of reduced filtration performance called “fouling”. In the case of microfiltration membranes and ultrafiltration membranes, filtration operation is repeated while repeating physical cleaning called backwashing with clarified water (hereinafter referred to as backwashing) or air scrubbing cleaning using air every few tens of minutes to several hours. To continue stably. The soiling substance peeled off from the membrane by this physical cleaning is discharged out of the membrane module system as physical cleaning waste water. Although the filtration operation can be continued by the physical washing as described above, there is a problem that the permeate recovery rate of the entire water treatment system is lowered because a part of the permeate is used for the physical washing.

さらに近年、膜を用いた水処理プラントの処理量が日量数万トン、日量数十万トンと大型化し、低コスト化が図られているため、透過水回収率の僅かな低下でも日量数千トン規模の物理洗浄排水が出ることになり、低環境負荷、低コスト、省エネルギーの観点から透過水回収率の低下は無視できない重要な課題の1つになってきている。   In recent years, the amount of water treatment plants using membranes has been increased to tens of thousands of tons per day and hundreds of thousands of tons per day to reduce costs. Physical washing wastewater with a scale of several thousand tons will come out, and from the viewpoint of low environmental load, low cost, and energy saving, the decline in permeate recovery rate has become one of the important issues that cannot be ignored.

特許文献1では、河川水等を膜ろ過した際に排出される膜の洗浄排水を汚泥の固形物濃度が5〜10%となるまで濃縮できる膜ろ過装置を具備する排水処理装置が開示されている。ここでは、膜洗浄排水を濃縮処理用膜装置で濃縮してから脱水機に導入することで年間を通じて安定した脱水処理を可能にし、透過水回収率を向上させることが述べられている。しかしながら、特許文献1では一段目、二段目の膜ろ過装置の回収率や膜ろ過流束、被処理水水質との関係については一切記載がなく、被処理水水質に応じた最適な二段膜ろ過プラントを設計し、運転維持管理するための技術に関しては開示されていない。   Patent Document 1 discloses a wastewater treatment apparatus including a membrane filtration device capable of concentrating washing wastewater from a membrane discharged when membrane water is filtered through a river until the solids concentration of sludge is 5 to 10%. Yes. Here, it is stated that the membrane washing wastewater is concentrated by a membrane device for concentration treatment and then introduced into a dehydrator, thereby enabling stable dewatering treatment throughout the year and improving the permeate recovery rate. However, Patent Document 1 does not describe any relationship between the recovery rate of the first-stage and second-stage membrane filtration devices, the membrane filtration flux, and the quality of the water to be treated, and the optimum two-stage according to the quality of the water to be treated. No technology is disclosed for designing and maintaining a membrane filtration plant.

特許文献2においても、被処理水を前処理してから膜ろ過し、その物理洗浄排水を二段目の膜ろ過装置でろ過してシステム全体の透過水回収率を99.9%以上にする技術が開示されているが、ここでは、二段目膜ろ過装置で一段目膜ろ過装置の物理洗浄排水を濃縮すれば、前処理として凝集剤を添加することなしに、汚泥の安定濃縮が可能であることが述べられているだけで、従来から実プラントで行われている二段膜ろ過システムを単に記載しているに過ぎない。特別な新規技術の提案も見受けられず、特許文献1と同様に、一段目、二段目の膜ろ過装置の回収率や膜ろ過流束、被処理水水質との関係については一切記載がない。
特開平11−57434号公報 特開2004−267887号公報
Also in Patent Document 2, the water to be treated is pretreated and then subjected to membrane filtration, and the physical washing wastewater is filtered by a second-stage membrane filtration device so that the permeate recovery rate of the entire system is 99.9% or more. Although the technology is disclosed here, if the physical washing wastewater of the first stage membrane filtration device is concentrated in the second stage membrane filtration device, stable concentration of sludge is possible without adding a flocculant as a pretreatment. Is merely a description of a two-stage membrane filtration system conventionally performed in actual plants. There is no proposal for a special new technology, and there is no description about the relationship between the recovery rate of the first and second stage membrane filtration devices, the membrane filtration flux, and the quality of the water to be treated, as in Patent Document 1. .
JP-A-11-57434 Japanese Patent Laid-Open No. 2004-267887

本発明は、低環境負荷、低コスト、省エネルギーの観点から水処理システム全体の透過水回収率を高めて、かつ被処理水水質に対して好適な二段膜ろ過システムを設計し、かつ該システムを安定に運転維持管理するための技術を提供することを目的とする。   The present invention is designed to improve the permeate recovery rate of the entire water treatment system from the viewpoint of low environmental load, low cost, and energy saving, and to design a two-stage membrane filtration system suitable for the quality of water to be treated. The purpose is to provide technology for stable operation and maintenance.

上記課題を解決するための本発明は、下記(1)〜(12)の構成によって達成される。   The present invention for solving the above problems is achieved by the following configurations (1) to (12).

(1)1)固有のパラメータa,b,cを有する限外ろ過膜モジュールまたは精密ろ過膜モジュールを具備する一段目ろ過手段、2)前記一段目ろ過手段の透過水側から被処理水側への送水することで、前記一段目ろ過手段を逆洗する物理洗浄手段、3)前記物理洗浄手段による洗浄時に排出された物理洗浄排水を膜ろ過する、固有のパラメータd,e,fを有する限外ろ過膜モジュールまたは精密ろ過膜モジュールを具備する二段目ろ過手段、4)前記一段目ろ過手段で膜ろ過する被処理水の平均濁度をT,前記二段目ろ過手段で膜ろ過する被処理水の平均濁度をTとしたとき、前記一段目ろ過手段における膜ろ過流束Fおよび透過水回収率R、ならびに前記二段目ろ過手段における膜ろ過流束Fおよび透過水回収率Rを、下式
=aT −b
=dT −e
=1−cF
=1−fF
を実質的に満たすように膜ろ過条件を制御する手段を有する二段膜ろ過システムであって、前記限外ろ過膜モジュールまたは精密ろ過膜モジュールに固有のパラメータa、b、c、d、e、fが
1.5≦a≦10
0.3≦b≦1
0.005≦c≦0.04
1.5≦d≦6
0.1≦e≦1
0.005≦f≦0.02
である二段膜ろ過システム。
(1) 1) First-stage filtration means comprising an ultrafiltration membrane module or microfiltration membrane module having unique parameters a, b, c 2) From the permeate side of the first-stage filtration means to the treated water side 3) Physical washing means for backwashing the first-stage filtration means, and 3) Filtering the physical washing drain discharged at the time of washing by the physical washing means with specific parameters d, e, and f Second-stage filtration means comprising an outer filtration membrane module or a microfiltration membrane module, 4) T 1 , the average turbidity of water to be treated for membrane filtration by the first-stage filtration means, and membrane filtration by the second-stage filtration means when the average turbidity of treatment water was T 2, the membrane filtration flux F 2 and transmission in membrane filtration flux F 1 and permeate recovery R 1, and the second stage filtration means in the first stage filtration unit water recovery rate R 2 , The following equation F 1 = aT 1 -b
F 2 = dT 2 −e
R 1 = 1-cF 1
R 2 = 1−fF 2
A two-stage membrane filtration system having means for controlling membrane filtration conditions so as to substantially satisfy the parameters a, b, c, d, e, unique to the ultrafiltration membrane module or the microfiltration membrane module. f is 1.5 ≦ a ≦ 10
0.3 ≦ b ≦ 1
0.005 ≦ c ≦ 0.04
1.5 ≦ d ≦ 6
0.1 ≦ e ≦ 1
0.005 ≦ f ≦ 0.02
Is a two-stage membrane filtration system.

(2)二段膜ろ過システム全体の透過水回収率Rを99.9%以上に制御する手段を有する(1)に記載の二段膜ろ過システム。   (2) The two-stage membrane filtration system according to (1), having means for controlling the permeate recovery rate R of the entire two-stage membrane filtration system to 99.9% or more.

(3)前記二段目膜ろ過装置の膜モジュールが浸漬型膜モジュールである(1)または(2)に記載の二段膜ろ過システム。   (3) The two-stage membrane filtration system according to (1) or (2), wherein the membrane module of the second-stage membrane filtration apparatus is an immersion type membrane module.

(4)前記一段目膜ろ過装置の膜モジュールが加圧型膜モジュールである(1)〜(3)のいずれかに記載の二段膜ろ過システム。   (4) The two-stage membrane filtration system according to any one of (1) to (3), wherein the membrane module of the first-stage membrane filtration apparatus is a pressure-type membrane module.

(5)前記一段目膜ろ過装置の膜モジュールが全量ろ過方式である(4)に記載の二段膜ろ過システム。   (5) The two-stage membrane filtration system according to (4), wherein the membrane module of the first-stage membrane filtration apparatus is a total filtration system.

(6)1)その固有のパラメータa,b,cが、
1.5≦a≦10
0.3≦b≦1
0.005≦c≦0.04
である限外ろ過膜モジュールまたは精密ろ過膜モジュールからなる一段目膜ろ過装置で、平均濁度Tの被処理水を、膜ろ過流束Fで透過水回収率をRで膜ろ過する一段目ろ過工程、2)前記一段目膜ろ過装置の透過水側から被処理水側に送水し、前記一段目膜ろ過装置を逆洗する工程を有する物理洗浄工程、3)その固有のパラメータd,e,fが、
1.5≦d≦6
0.1≦e≦1
0.005≦f≦0.02
である限外ろ過膜モジュールまたは精密ろ過膜モジュールからなる二段目膜ろ過装置で、前記物理洗浄工程から排出された平均濁度Tの物理洗浄排水を、膜ろ過流束Fで透過水回収率をRで膜ろ過する二段目ろ過工程を有する二段膜ろ過システムの運転方法であって、前記平均濁度T,T、前記膜ろ過流束F,F、および前記透過水回収率R,Rを実質的に、
=aT −b
=dT −e
=1−cF
=1−fF
となるように運転して、前記一段目ろ過工程および前記二段目ろ過工程から透過水を回収する二段膜ろ過システムの運転方法。
(6) 1) The unique parameters a, b, c are
1.5 ≦ a ≦ 10
0.3 ≦ b ≦ 1
0.005 ≦ c ≦ 0.04
The membrane to be treated having an average turbidity T 1 is subjected to membrane filtration with a membrane filtration flux F 1 and a permeate recovery rate of R 1. 1st-stage filtration process, 2) Physical washing process including the process of feeding water from the permeate side of the 1st-stage membrane filtration apparatus to the treated water side and backwashing the 1st-stage membrane filtration apparatus, and 3) its inherent parameter d , E, f
1.5 ≦ d ≦ 6
0.1 ≦ e ≦ 1
0.005 ≦ f ≦ 0.02
In the second-stage membrane filtration apparatus comprising an ultrafiltration membrane module or a microfiltration membrane module, the physical washing wastewater having an average turbidity T 2 discharged from the physical washing step is permeated with a membrane filtration flux F 2. An operation method of a two-stage membrane filtration system having a second-stage filtration step of membrane filtration with R 2 , wherein the average turbidity T 1 , T 2 , the membrane filtration fluxes F 1 , F 2 , and The permeate recovery rates R 1 and R 2 are substantially
F 1 = aT 1 -b
F 2 = dT 2 −e
R 1 = 1-cF 1
R 2 = 1−fF 2
The operation method of the two-stage membrane filtration system which is operated so that the permeated water is recovered from the first-stage filtration step and the second-stage filtration step.

(7)二段膜ろ過システム全体の透過水回収率Rが99.9%以上の(6)に記載の二段膜ろ過システムの運転方法。   (7) The operation method of the two-stage membrane filtration system according to (6), wherein the permeate recovery rate R of the entire two-stage membrane filtration system is 99.9% or more.

(8)前記二段目膜ろ過装置の膜モジュールが浸漬型膜モジュールである(6)または(7)に記載の二段膜ろ過システムの運転方法。   (8) The operation method of the two-stage membrane filtration system according to (6) or (7), wherein the membrane module of the second-stage membrane filtration apparatus is an immersion type membrane module.

(9)前記一段目膜ろ過装置の膜モジュールが加圧型膜モジュールである(6)〜(8)のいずれかに記載の二段膜ろ過システムの運転方法。   (9) The operation method of the two-stage membrane filtration system according to any one of (6) to (8), wherein the membrane module of the first-stage membrane filtration device is a pressure type membrane module.

(10)前記一段目膜ろ過装置の膜モジュールが全量ろ過方式である(9)に記載の二段膜ろ過システムの運転方法。   (10) The operation method of the two-stage membrane filtration system according to (9), wherein the membrane module of the first-stage membrane filtration apparatus is a total filtration system.

(11)限外ろ過膜モジュールまたは精密ろ過膜モジュールに固有のパラメータであるa、b、c、d、e、fが、
5≦a≦8
0.4≦b≦0.8
0.016≦c≦0.03
2.5≦d<5
0.2≦e<0.4
0.01≦f<0.016
であることを特徴とする(1)〜(5)に記載の二段膜ろ過システム。
(11) Parameters a, b, c, d, e, and f unique to the ultrafiltration membrane module or the microfiltration membrane module are
5 ≦ a ≦ 8
0.4 ≦ b ≦ 0.8
0.016 ≦ c ≦ 0.03
2.5 ≦ d <5
0.2 ≦ e <0.4
0.01 ≦ f <0.016
The two-stage membrane filtration system according to any one of (1) to (5), wherein

(12)限外ろ過膜モジュールまたは精密ろ過膜モジュールに固有のパラメータであるa、b、c、d、e、fが、
5≦a≦8
0.4≦b≦0.8
0.016≦c≦0.03
2.5≦d<5
0.2≦e<0.4
0.01≦f<0.016
であることを特徴とする(6)〜(10)に記載の二段膜ろ過システムの運転方法。
(12) Parameters a, b, c, d, e, and f unique to the ultrafiltration membrane module or the microfiltration membrane module are
5 ≦ a ≦ 8
0.4 ≦ b ≦ 0.8
0.016 ≦ c ≦ 0.03
2.5 ≦ d <5
0.2 ≦ e <0.4
0.01 ≦ f <0.016
The method for operating a two-stage membrane filtration system according to any one of (6) to (10), wherein

本発明によれば、従来95%程度であった透過水回収率を99.9%にまで高めた限外ろ過膜または精密ろ過膜からなる水処理システムが提供される。被処理水水質に対して好適な二段膜ろ過システムを設計し、かつ該システムを安定に運転維持管理するための技術が提供され、低環境負荷、低コスト、省エネルギーの観点から優れた水処理システムが得られる。特に大処理量の大型膜ろ過プラントにおいては安定運転が出来なかった時のリスクが大きいが、本発明によれば、一段目の膜ろ過装置と二段目の膜ろ過装置で好適にリスクを分散させることも可能となる。   ADVANTAGE OF THE INVENTION According to this invention, the water treatment system which consists of an ultrafiltration membrane or a microfiltration membrane which raised the permeated water collection | recovery rate which was about 95% conventionally to 99.9% is provided. Designing a two-stage membrane filtration system suitable for the quality of the water to be treated and providing a technology for stable operation and maintenance of the system, providing excellent water treatment from the viewpoint of low environmental load, low cost, and energy saving A system is obtained. Especially in large membrane filtration plants with large throughput, the risk is high when stable operation is not possible, but according to the present invention, the risk is suitably distributed between the first-stage membrane filtration device and the second-stage membrane filtration device. It is also possible to make it.

本発明の二段膜ろ過システムを図1の例を用いて詳細に説明する。なお、本発明は、図1に示される二段膜ろ過システムに限定されるものではない。   The two-stage membrane filtration system of the present invention will be described in detail using the example of FIG. The present invention is not limited to the two-stage membrane filtration system shown in FIG.

被処理水タンク1に導いた被処理水を、一段目膜ろ過装置のポンプ2で一段目膜ろ過装置3に供給し、透過水を透過水タンク6に蓄える。透過水タンク6に蓄えた透過水の一部を、逆洗用ポンプ7を用いて、一段目膜ろ過装置3の透過側から被処理水側へ送水して、一段目膜ろ過装置の逆洗を行う。また、膜モジュールが中空糸膜モジュールの場合には、膜モジュールの下部から空気を導入して中空糸膜を揺らすエアースクラビング洗浄なども一般に行われる。これら逆洗やエアースクラビング洗浄などの物理洗浄は、数十分から数時間毎に行われ、通常はこの物理洗浄度に物理洗浄排水が発生する。発生する物理洗浄排水は二段目膜ろ過装置4に導かれ、二段目膜ろ過装置のポンプ5を用いてろ過されて透過水タンク6に送水される。   The treated water led to the treated water tank 1 is supplied to the first-stage membrane filtration device 3 by the pump 2 of the first-stage membrane filtration device, and the permeated water is stored in the permeated water tank 6. A portion of the permeate stored in the permeate tank 6 is fed from the permeate side of the first-stage membrane filtration device 3 to the treated water side using the backwash pump 7 to backwash the first-stage membrane filter device. I do. In the case where the membrane module is a hollow fiber membrane module, air scrubbing cleaning in which air is introduced from the lower part of the membrane module to shake the hollow fiber membrane is generally performed. These physical washings such as back washing and air scrubbing washing are performed every several tens of minutes to several hours, and usually physical washing wastewater is generated at this degree of physical washing. The generated physical washing wastewater is guided to the second stage membrane filtration device 4, filtered using the pump 5 of the second stage membrane filtration device, and sent to the permeate tank 6.

本発明者らは、図1に示す二段膜ろ過システムにおいて、被処理水タンク1に導かれた被処理水の平均濁度T、一段目膜ろ過装置3の物理洗浄排水平均濁度(二段目膜ろ過装置への膜供給水平均濁度)T、一段目膜ろ過装置の膜ろ過流束F、二段目膜ろ過装置の膜ろ過流束F、一段目膜ろ過装置の透過水回収率R、二段目膜ろ過装置の透過水回収率Rの関係について鋭意検討した結果、一段目の膜ろ過装置を高膜ろ過流束で低透過水回収率、二段目の膜ろ過装置を低膜ろ過流束で高透過水回収率とすることで、一段目膜ろ過装置の膜面積と二段目膜ろ過装置の膜面積の合計膜面積を減らし、かつ、一段目膜ろ過装置および二段目膜ろ過装置が安定に運転を継続でき、その結果、低コストで透過水の安定供給に対するリスクの少ない二段膜ろ過システムが得られることを見出した。 In the two-stage membrane filtration system shown in FIG. 1, the present inventors have determined the average turbidity T 1 of the water to be treated introduced into the water tank 1 to be treated and the average turbidity of physical washing wastewater from the first-stage membrane filtration device 3 ( Membrane feed water average turbidity to the second stage membrane filtration device) T 2 , membrane filtration flux F 1 of the first stage membrane filtration device, membrane filtration flux F 2 of the second stage membrane filtration device, first stage membrane filtration device As a result of intensive studies on the relationship between the permeated water recovery rate R 1 and the permeated water recovery rate R 2 of the second-stage membrane filtration device, the first-stage membrane filtration device has a low permeated water recovery rate with a high membrane filtration flux. By making the membrane filtration device of the eye a high permeate recovery rate with a low membrane filtration flux, the total membrane area of the membrane area of the first-stage membrane filtration device and the membrane area of the second-stage membrane filtration device is reduced, and The membrane filtration device and the second-stage membrane filtration device can continue to operate stably. As a result, there is a risk for stable supply of permeated water at low cost. Two-stage membrane filtration system less found that obtained.

ここで、膜ろ過流束とは、膜モジュールの透過水流量(m/日)を膜面積(m)で割った値であり、単位はm/日である。また、透過水回収率とは、膜ろ過装置の1サイクルのろ過で得られた透過水量から物理洗浄で発生する物理洗浄排水量を引いた値を1回のろ過サイクルで得られた透過水量で割った値に100をかけた値で、単位は%である。二段膜ろ過システム全体の透過水回収率Rとは、透過水タンク6から流出する透過水の平均流量を被処理水タンク1への被処理水流入流量で割った値に100をかけた値である。従来、膜ろ過装置の透過水回収率は95%程度であったが、以下に詳述する本発明の二段膜ろ過システムを用いることで99.9%以上の透過水回収率が得られる。 Here, the membrane filtration flux is a value obtained by dividing the permeate flow rate (m 3 / day) of the membrane module by the membrane area (m 2 ), and the unit is m / day. The permeate recovery rate is calculated by subtracting the amount of permeated water obtained in one filtration cycle from the amount of permeated water obtained by filtration in one cycle of the membrane filtration device minus the amount of physical washing wastewater generated in physical washing. The value is obtained by multiplying the measured value by 100, and the unit is%. The permeate recovery rate R of the entire two-stage membrane filtration system is a value obtained by multiplying the value obtained by dividing the average flow rate of the permeate flowing out of the permeate tank 6 by the inflow rate of the treated water flowing into the treated water tank 1 by 100. It is. Conventionally, the permeate recovery rate of the membrane filtration device was about 95%, but a permeate recovery rate of 99.9% or more can be obtained by using the two-stage membrane filtration system of the present invention described in detail below.

二段膜ろ過システム全体処理流量の主系統の一段目膜ろ過装置を低膜ろ過流束とすると、一段目膜ろ過装置の膜面積が増加し、膜モジュール費用がかさむと共に、システム全体の設置面積の増加、加えて膜モジュールを接続するパイプやフランジや電動弁の数が増えて設備費が増加する。さらに一段目を低膜ろ過流束にすると一段目透過水回収率を高めに設定する必要が生じ、二段目膜ろ過装置の膜供給水平均濁度が高くなり、二段目の安定運転が難しくなる。また二段膜ろ過システム全体処理流量のうちの僅かな処理量である回収系統の二段目膜ろ過装置の膜透過流束を高めても二段膜ろ過システム全体の膜面積から見て僅かな膜面積しか低減できず、トータルコスト低減への寄与が小さいだけでなく、二段目膜ろ過装置の膜供給水平均濁度が高いことから安定運転も難しくなる。   If the first-stage membrane filtration device of the main system of the overall flow rate of the two-stage membrane filtration system is a low membrane filtration flux, the membrane area of the first-stage membrane filtration device increases, the membrane module costs increase, and the installation area of the entire system In addition, the number of pipes, flanges, and motor-operated valves that connect the membrane module increases, resulting in an increase in equipment costs. Furthermore, if the first stage has a low membrane filtration flux, it will be necessary to set the first stage permeate recovery rate higher, the membrane feed water average turbidity of the second stage membrane filtration device will be higher, and stable operation of the second stage will be possible. It becomes difficult. Moreover, even if the membrane permeation flux of the second-stage membrane filtration device of the recovery system, which is a slight processing amount of the entire processing flow rate of the two-stage membrane filtration system, is increased, the membrane area of the entire two-stage membrane filtration system is slight. Only the membrane area can be reduced, and not only the contribution to the total cost reduction is small, but also the stable operation is difficult because the membrane feed water average turbidity of the second-stage membrane filtration device is high.

上述したように一段目の膜ろ過装置を高膜ろ過流束で低透過水回収率、二段目の膜ろ過装置を低膜ろ過流束で高透過水回収率とする本発明の二段膜ろ過システムを達成するためには、一段目の膜ろ過装置の膜モジュールに高膜ろ過流束で安定運転できる膜モジュールを、二段目の膜ろ過装置に高平均濁度膜供給水に対して高透過水回収率運転が可能な膜モジュールを採用することが必要である。一段目、二段目それぞれの膜ろ過装置の膜ろ過流束や透過水回収率の関係を種々検討したところ、次の関係式を満たすような膜モジュールを採用し、かつ次の関係式を満たすように膜ろ過流束および透過水回収率を制御することが可能なろ過手段を配してなる二段膜ろ過システムによって被処理水水質に好適で低コストな二段膜ろ過システムが得られることを本発明者らは見出した。
=aT −b
=dT −e
=1−cF
=1−fF
1.5≦a≦10
0.3≦b≦1
0.005≦c≦0.04
1.5≦d≦6
0.1≦e≦1
0.005≦f≦0.02
ここで、a、b、c、d、e、fは膜モジュール固有のパラメータである。
As described above, the first-stage membrane filtration device has a high permeate filtration flux and a low permeate recovery rate, and the second-stage membrane filtration device has a low membrane filtration flux and a high permeate recovery rate. In order to achieve a filtration system, a membrane module capable of stable operation with a high membrane filtration flux is installed in the membrane module of the first stage membrane filtration device, and a high average turbidity membrane feed water is supplied to the second membrane filtration device. It is necessary to adopt a membrane module capable of high permeate recovery rate operation. Various studies were made on the relationship between the membrane filtration flux and the permeate recovery rate of the membrane filtration devices in the first and second stages. As a result, a membrane module that satisfies the following relational expression was adopted and the following relational expression was satisfied: A low-cost two-stage membrane filtration system suitable for the quality of water to be treated can be obtained by a two-stage membrane filtration system comprising filtration means capable of controlling the membrane filtration flux and the permeate recovery rate. The present inventors have found out.
F 1 = aT 1 -b
F 2 = dT 2 −e
R 1 = 1-cF 1
R 2 = 1−fF 2
1.5 ≦ a ≦ 10
0.3 ≦ b ≦ 1
0.005 ≦ c ≦ 0.04
1.5 ≦ d ≦ 6
0.1 ≦ e ≦ 1
0.005 ≦ f ≦ 0.02
Here, a, b, c, d, e, and f are parameters specific to the membrane module.

aおよびdは膜モジュール自身の濁質に対する耐汚れ性のポテンシャルを表現すると考えられるパラメータで、大きければ高い膜ろ過流束で運転可能であること、小さければ高い膜ろ過流束での運転が難しいことを表す。このことを踏まえると高膜ろ過流束が必要な一段目膜モジュールに固有の定数aは1.5以上10以下、好ましくは3以上9以下、さらに好ましくは5以上8以下であり、二段目膜モジュールに固有の定数dは1.5以上6以下、好ましくは2以上5.5以下、さらに好ましくは2.5以上5未満である。   a and d are parameters that are considered to express the potential of dirt resistance to turbidity of the membrane module itself. If it is large, it can be operated with a high membrane filtration flux, and if it is small, it is difficult to operate with a high membrane filtration flux. Represents that. In view of this, the constant a inherent to the first-stage membrane module requiring high membrane filtration flux is 1.5 or more and 10 or less, preferably 3 or more and 9 or less, more preferably 5 or more and 8 or less. The constant d inherent to the membrane module is 1.5 or more and 6 or less, preferably 2 or more and 5.5 or less, and more preferably 2.5 or more and less than 5.

bおよびeは濁質量の変化に対する膜モジュールの安定運転可能上限膜ろ過流束の変化量の大小を表現すると考えられるパラメータで、大きければ濁質量の変化に対する安定運転可能上限膜ろ過流束の変化量が大きく、小さければ変化量は大きくないことを表す。高膜ろ過流束での安定運転が必要な一段目膜モジュールに固有の定数bは0.3以上1以下、好ましくは0.35以上0.9以下、さらに好ましくは0.4以上0.8以下であり、二段目膜モジュールに固有の定数eは0.1以上1以下、好ましくは0.15以上0.7以下、さらに好ましくは0.2以上0.4未満である
cおよびfは安定運転のために必要な物理洗浄の量を表現すると考えられるパラメータで、小さければ必要な物理洗浄の量が少なく高い膜ろ過流束においても高い透過水回収率で運転可能なことを、大きければ膜ろ過流束の増加に伴い安定運転可能な透過水回収率の低下が大きいことを表す。高透過水回収率運転が求められる二段目膜モジュールに固有の定数fは0.005以上0.02以下、好ましくは0.008以上0.018以下、さらに好ましくは0.01以上0.016未満であり、一段目膜モジュールに固有の定数cは0.005以上0.04以下、好ましくは0.01以上0.035以下、さらに好ましくは0.016以上0.03以下である。
b and e are parameters that are considered to express the amount of change in the maximum membrane filtration flux for stable operation of the membrane module with respect to changes in turbid mass. If the amount is large and small, the amount of change is not large. The constant b inherent to the first-stage membrane module that requires stable operation at a high membrane filtration flux is 0.3 or more and 1 or less, preferably 0.35 or more and 0.9 or less, more preferably 0.4 or more and 0.8. The constant e unique to the second-stage membrane module is 0.1 or more and 1 or less, preferably 0.15 or more and 0.7 or less, more preferably 0.2 or more and less than 0.4. C and f are This parameter is considered to represent the amount of physical washing required for stable operation. If it is small, the amount of physical washing required is small, and it is possible to operate with a high permeate recovery rate even in a high membrane filtration flux. This means that the permeate recovery rate that can be stably operated is greatly reduced as the membrane filtration flux increases. The constant f inherent to the second-stage membrane module requiring high permeate recovery rate operation is 0.005 or more and 0.02 or less, preferably 0.008 or more and 0.018 or less, more preferably 0.01 or more and 0.016. The constant c inherent to the first-stage membrane module is 0.005 or more and 0.04 or less, preferably 0.01 or more and 0.035 or less, and more preferably 0.016 or more and 0.03 or less.

特に、aを5以上8以下、dを2.5以上5未満とし、bを0.4以上0.8以下、eを0.2以上0.4未満とし、cを0.016以上0.03以下、fを0.01以上0.016未満とすることで、一段目の膜ろ過装置を高膜ろ過流束で低透過水回収率とし、二段目の膜ろ過装置を低膜ろ過流束で高透過水回収率とすることを顕著に実現でき、好ましい。   In particular, a is 5 or more and 8 or less, d is 2.5 or more and less than 5, b is 0.4 or more and 0.8 or less, e is 0.2 or more and less than 0.4, and c is 0.016 or more and 0.00. 03 or less, and by setting f to 0.01 or more and less than 0.016, the first stage membrane filtration device has a low permeate recovery rate with a high membrane filtration flux, and the second stage membrane filtration device has a low membrane filtration flow. It is possible to realize a high permeate recovery rate with a bundle, which is preferable.

次に、定数a、b、c、d、e、fの求め方について述べる。まず被処理水の平均濁度Tと膜ろ過流束Fの関係については、二段膜ろ過システムに採用する膜モジュールを用いて被処理水平均濁度Tを変化させたときの安定運転可能な上限膜ろ過流束Fを求め、その実験結果をF=aT−bの関数にフィッティングすることにより定数a、bを決める。定数の決定については、異なる被処理水平均濁度のデータを少なくとも3点、好ましくは4点、更に好ましくは5点以上用いて決定する。関数のフィッティングには最小自乗法を用いることが好ましく採用できる。 Next, how to obtain the constants a, b, c, d, e, and f will be described. First, regarding the relationship between the average turbidity T of the water to be treated and the membrane filtration flux F, stable operation is possible when the average turbidity T of the water to be treated is changed using the membrane module employed in the two-stage membrane filtration system. The upper limit membrane filtration flux F is obtained, and the constants a and b are determined by fitting the experimental result to a function of F = aT− b . The constants are determined using at least 3 points, preferably 4 points, and more preferably 5 points or more of data of different average turbidity of water to be treated. It is preferable to use the method of least squares for function fitting.

次いで膜ろ過流束Fと透過水回収率Rの関係であるが、これについては二段膜ろ過システムに採用する膜モジュールを用いて被処理水平均濁度Tを変化させ、先に求めた被処理水平均濁度Tに対する安定運転可能な上限膜ろ過流束Fで膜ろ過を行い、この時の安定運転可能な上限回収率Rを求め、その実験結果をR=1−cFの関数にフィッティングすることにより定数cを決める。以上の手順を一段目膜ろ過装置および二段目膜ろ過装置の双方で行い、二段膜ろ過システム設計に必要な関係式を得る。   Next, the relationship between the membrane filtration flux F and the permeate recovery rate R is as follows. For this, the average turbidity T of the water to be treated is changed using the membrane module employed in the two-stage membrane filtration system, and the previously obtained coverage is obtained. Membrane filtration is performed with the upper limit membrane filtration flux F capable of stable operation with respect to the average turbidity T of the treated water, the upper limit recovery rate R capable of stable operation at this time is obtained, and the experimental results are fitted to a function of R = 1-cF. To determine the constant c. The above procedure is performed in both the first-stage membrane filtration apparatus and the second-stage membrane filtration apparatus, and the relational expressions necessary for designing the second-stage membrane filtration system are obtained.

なお、そのようなa,b,cを有する限外ろ過膜モジュールまたは精密ろ過膜モジュール、ならびに、そのようなd,e,fを有する限外ろ過膜モジュールまたは精密ろ過膜モジュールとしては、公知の方法によって得られるもので良い。   In addition, as an ultrafiltration membrane module or microfiltration membrane module having such a, b and c, and an ultrafiltration membrane module or microfiltration membrane module having such d, e and f, known It may be obtained by a method.

次に、前記限外ろ過膜モジュールまたは精密ろ過膜モジュールを用いて本発明の二段膜ろ過システムにおいて一段目膜ろ過装置および二段目膜ろ過装置の膜ろ過流束F、Fおよび透過水回収率R、Rを特定の関係を保つように運転条件に制御して膜ろ過を行う二段膜ろ過システムの運転方法を述べる。 Next, using the ultrafiltration membrane module or the microfiltration membrane module, in the two-stage membrane filtration system of the present invention, the membrane filtration fluxes F 1 and F 2 and the permeation of the first- stage membrane filtration apparatus and the second-stage membrane filtration apparatus. An operation method of a two-stage membrane filtration system that performs membrane filtration by controlling the water recovery rates R 1 and R 2 to operating conditions so as to maintain a specific relationship will be described.

被処理水平均濁度TからF=aT −bの関係を用いて一段目膜ろ過装置の膜ろ過流束Fを求める。次いで、このFからR=1−cFの関係を用いて一段目膜ろ過装置の透過水回収率Rを求める。Rが決まるとT=T/(1−R)の関係から二段目膜ろ過装置の膜供給水平均濁度Tが求まる。Tが決まればF=dT −eの関係から二段目膜ろ過装置の膜ろ過流束Fを決めることができ、このFからR=1−fFの関係を用いて二段目膜ろ過装置の透過水回収率Rが決まる。以上のような手順で定まったF、F、R、Rを維持するように制御して膜ろ過を行う二段膜ろ過システムの運転方法とするのが本発明の要旨である。なお、一段目ろ過工程、二段目ろ過工程、および物理洗浄工程の各運転条件の制御は、二段膜ろ過システムを構成する各装置(各手段)に内蔵されたPLC(プログラマブルコントローラー)にあらかじめ記録させ自動的に実行させることができる。 From the water to be treated an average turbidity T 1 using the relationship of F 1 = aT 1 -b seek membrane filtration flux F 1 of the first stage membrane filtration device. Next, the permeated water recovery rate R 1 of the first- stage membrane filtration apparatus is obtained using the relationship of F 1 to R 1 = 1−cF 1 . When R 1 is determined, the membrane feed water average turbidity T 2 of the second-stage membrane filtration device is determined from the relationship of T 2 = T 1 / (1-R 1 ). If T 2 is Kimare F 2 = dT 2 from -e relationship can decide membrane filtration flux F 2 of the second stage membrane filtration apparatus, from the F 2 using the relationship R 2 = 1-fF 2 permeate recovery of second stage membrane filtration units R 2 is determined. The gist of the present invention is an operation method of a two-stage membrane filtration system that performs membrane filtration while controlling F 1 , F 2 , R 1 , and R 2 determined by the above procedure. In addition, the control of each operation condition of the first stage filtration process, the second stage filtration process, and the physical cleaning process is performed in advance by a PLC (programmable controller) built in each device (each means) constituting the second stage membrane filtration system. It can be recorded and automatically executed.

なお、上記の方法で膜ろ過流束および透過水回収率を決めると被処理水の平均濁度に応じて最適な膜ろ過流束および透過水回収率がそれぞれ1点のみしか得られないことになる。しかしながら、実際は安定運転可能で好適な膜ろ過流束および透過水回収率にはある幅が存在する。よって本発明においては、上記関係式を実質的に満たすように運転すれば本発明の目的は達成される。ここで、実質的に満たすとは、膜ろ過流束および透過水回収率の値を中央に、膜ろ過流束については±10%の範囲の値を、透過水回収率については±2%の範囲の値を本発明の一段目膜ろ過装置および二段目膜ろ過装置の膜ろ過流束および透過水回収率として制御することをいう。   When the membrane filtration flux and the permeate recovery rate are determined by the above method, only one optimum membrane filtration flux and permeate recovery rate can be obtained according to the average turbidity of the water to be treated. Become. However, in practice, there is a certain range of membrane filtration flux and permeate recovery rate that can be stably operated. Therefore, in the present invention, the object of the present invention can be achieved by operating so as to substantially satisfy the above relational expression. Here, substantially satisfying means that the value of the membrane filtration flux and the permeate recovery rate is in the center, the value of the membrane filtration flux is within a range of ± 10%, and the value of the permeate recovery rate is ± 2%. The range value is controlled as the membrane filtration flux and permeate recovery rate of the first-stage membrane filtration device and the second-stage membrane filtration device of the present invention.

また、一段目膜ろ過装置および二段目膜ろ過装置のろ過差圧上昇速度の推移を見ながら、膜ろ過流束については±10%、透過水回収率については±2%の範囲において膜ろ過流束や透過水回収率を変更して、例えば一時的な高濁度被処理水流入時にも一段目膜ろ過装置および二段目膜ろ過装置のろ過差圧上昇速度が小さくなるように運転条件を変更、制御することも好ましく、本発明の範囲に含まれるものとする。
本発明の膜ろ過装置に用いられる分離膜の形状には、中空糸膜、管状膜、平膜などがあり、いずれの形状のものでも本発明に用いることができるが、一般的な飲料水製造分野すなわち浄水処理過程、用水製造や排水処理などの水処理用途には、装置単位体積あたりの有効膜面積を大きくできる中空糸膜が好ましくい採用できる。中空糸膜モジュールには中空糸膜が容器に収納され、被処理水をポンプ等で加圧供給して透過水を得る加圧型膜モジュールと、膜供給水をタンクなどに入れて、そのタンクの中に直接膜モジュールを浸漬して吸引ろ過する浸漬膜モジュールの大きく2種類があり、本発明ではいずれの膜モジュールも採用できる。しかしながら本発明のポイントは、一段目の膜ろ過装置を高膜ろ過流束で低透過水回収率、二段目の膜ろ過装置を低膜ろ過流束で高透過水回収率とすることであり、このためには一段目の膜ろ過装置では高膜ろ過流束に有利な加圧型膜モジュールを、二段目の膜ろ過装置では高平均濁度被処理水の高透過水回収率運転に適した浸漬膜モジュールを採用することが好ましい。
In addition, while observing the transition of the rate of increase in the differential pressure of the first-stage membrane filtration device and the second-stage membrane filtration device, membrane filtration in the range of ± 10% for membrane filtration flux and ± 2% for permeate recovery rate Change the flux and permeate recovery rate, for example, operating conditions so that the rate of increase in the filtration differential pressure of the first-stage membrane filtration device and the second-stage membrane filtration device becomes small even when temporarily treated with high turbidity treated water. It is also preferable to change and control the above, and it is included in the scope of the present invention.
Examples of the shape of the separation membrane used in the membrane filtration device of the present invention include a hollow fiber membrane, a tubular membrane, and a flat membrane, and any shape can be used in the present invention. A hollow fiber membrane that can increase the effective membrane area per unit unit volume can be preferably used in the field, that is, water treatment applications such as water purification processes, water production, and wastewater treatment. In the hollow fiber membrane module, a hollow fiber membrane is housed in a container, and a pressurized membrane module that obtains permeated water by supplying pressurized water to be treated with a pump or the like, and the membrane supply water into a tank or the like. There are roughly two types of submerged membrane modules in which the membrane module is directly immersed and suction filtered, and any membrane module can be employed in the present invention. However, the point of the present invention is that the first stage membrane filtration device has a high permeate recovery rate with a high membrane filtration flux, and the second stage membrane filtration device has a high permeate recovery rate with a low membrane filtration flux. For this purpose, a pressurized membrane module that is advantageous for high membrane filtration flux in the first stage membrane filtration device, and a high permeate recovery rate operation suitable for high average turbidity treated water in the second stage membrane filtration device It is preferable to employ an immersion membrane module.

本発明に用いられる分離膜は、細孔径が1nm以上10μm以下のいわゆる精密ろ過膜または限外ろ過膜に分類される分離膜である。逆浸透膜やナノろ過膜は一般には物理洗浄を行わず、さらにシステムの設計思想が異なるため本発明には含まれない。ここで、分離膜の細孔径は、以下に述べる方法で測定する。すなわち、分離膜の透水性Lと水の膜ろ過速度Jから、次式の関係を使って計算して求める。 The separation membrane used in the present invention is a separation membrane classified as a so-called microfiltration membrane or ultrafiltration membrane having a pore diameter of 1 nm to 10 μm. Generally, reverse osmosis membranes and nanofiltration membranes are not included in the present invention because they are not physically washed, and the system design philosophy is different. Here, the pore diameter of the separation membrane is measured by the method described below. That is, the membrane filtration rate J v Permeability L p and water separation membrane, obtained by calculation using the following relation.

=L・ΔP
= (H/L)・(R /8η)
ここで、ΔPは膜間圧力差、Hは平均の膜空隙率、Lは膜厚、Rは平均細孔径、ηは水の粘性である。
J v = L p · ΔP
L p = (H / L) · (R p 2 / 8η)
Here, ΔP is the transmembrane pressure difference, H is the average membrane porosity, L is the film thickness, R p is the average pore diameter, and η is the viscosity of water.

精密ろ過膜または限外ろ過膜の素材には、ポリアクリロニトリル、ポリスルフォン、ポリエーテルスルフォン、ポリフェニレンスルフォン、ポリフェニレンスルフィドスルフォン、ポリフッ化ビニリデン、酢酸セルロース、ポリエチレン、ポリプロピレン、セラミック等の無機素材等を挙げることができ、本発明の主旨から言って特に限定されないが、化学的耐久性が高いポリフッ化ビニリデンや親水性の素材であり汚れにくいポリアクリロニトリル、酢酸セルロースが好ましい。   Examples of the material for the microfiltration membrane or ultrafiltration membrane include inorganic materials such as polyacrylonitrile, polysulfone, polyether sulfone, polyphenylene sulfone, polyphenylene sulfide sulfone, polyvinylidene fluoride, cellulose acetate, polyethylene, polypropylene, ceramic, etc. Although not particularly limited in view of the gist of the present invention, polyvinylidene fluoride having high chemical durability, polyacrylonitrile and cellulose acetate which are hydrophilic materials and are difficult to get dirty are preferable.

本発明における被処理水とは一段目膜ろ過装置の膜モジュールに供給される膜供給水のことで、例えば浄水処理分野では主に河川水、湖沼水、地下水などの自然水が被処理水となる。被処理水は下水の2次処理水、海水などでも構わない。   The treated water in the present invention is a membrane supply water supplied to the membrane module of the first-stage membrane filtration device. For example, in the water purification treatment field, natural water such as river water, lake water, and ground water is mainly treated water. Become. The treated water may be sewage secondary treated water or seawater.

膜ろ過装置とは、少なくとも原液側に加圧手段もしくは透過液側に吸引手段を設けて、透過水の製造を行う装置のことである。加圧手段としてはポンプを用いてもよいし、また水位差による圧力を利用してもよい。また、吸引手段としては、ポンプやサイフォンを利用すればよい。この膜ろ過装置を二段に組合せ、一段目膜ろ過装置の物理洗浄排水を二段目の膜ろ過装置でろ過するシステムが本発明の二段膜ろ過システムである。   The membrane filtration device is a device for producing permeated water by providing at least a pressurizing means on the stock solution side or a suction means on the permeate side. A pump may be used as the pressurizing means, or a pressure due to a water level difference may be used. Moreover, what is necessary is just to utilize a pump and a siphon as a suction means. A system in which this membrane filtration device is combined in two stages and the physical washing wastewater of the first stage membrane filtration device is filtered by the second stage membrane filtration device is the two-stage membrane filtration system of the present invention.

膜分離装置の運転には、定流量ろ過および定圧ろ過があるが、本発明は膜ろ過流束と透過水回収率を好適に決定する技術を提供するものであり、定流量ろ過運転に限定される。   The operation of the membrane separator includes constant flow filtration and constant pressure filtration, but the present invention provides a technique for suitably determining the membrane filtration flux and the permeate recovery rate, and is limited to the constant flow filtration operation. The

また、被処理水の分離膜への供給の仕方で、被処理水の全量をろ過する全量ろ過運転と分離膜モジュールに供給した被処理水の一部を被処理水に返送するクロスフローろ過運転がある。本発明の主旨から言えばいずれのろ過運転方式でも構わないが、全量ろ過運転の方が設備が単純で運転管理し易く、物理洗浄排水以外の膜供給水のすべてを透過水として得られるので、エネルギーコストの低減につながり有利であり好ましい。   In addition, the total amount of filtration operation that filters the total amount of water to be treated and the cross-flow filtration operation that returns a part of the water to be treated supplied to the separation membrane module to the water to be treated. There is. Speaking from the gist of the present invention, any filtration operation method may be used, but the total amount filtration operation is simpler and easier to manage, and all the membrane feed water other than the physical washing wastewater can be obtained as permeate. This is advantageous because it leads to a reduction in energy costs.

以下に具体的実施例を挙げて本発明を説明するが、本発明はこれら実施例により何ら限定されるものではない。   The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples.

二段膜ろ過システムの性能評価は、以下に述べる琵琶湖水を用いた運転性評価によって行った。2週間〜3ヶ月間のろ過差圧推移を計測して、次式により1日平均のろ過差圧上昇速度(kPa/日)を算出して比較した。   The performance evaluation of the two-stage membrane filtration system was performed by the drivability evaluation using Lake Biwa water described below. The change in filtration pressure difference between 2 weeks and 3 months was measured, and the daily average filtration pressure increase rate (kPa / day) was calculated and compared using the following formula.

ろ過差圧上昇速度(kPa/日)=(P−P)/T
ここで運転評価開始時点の物理洗浄直後のろ過差圧をP(kPa)、運転評価終了時点の該ろ過差圧をP(kPa)、運転期間をT(日)とする。
Filtration differential pressure increase rate (kPa / day) = (P 1 −P 0 ) / T
Here, the filtration differential pressure immediately after the physical cleaning at the start of the operation evaluation is P 0 (kPa), the filtration differential pressure at the end of the operation evaluation is P 1 (kPa), and the operation period is T (day).

ろ過差圧上昇速度が0.35kPa/日程度以下であれば、6ヶ月の運転で約60kPaのろ過差圧上昇である。運転初期ろ過差圧が20〜30kPa程度であり、薬液洗浄の目安がろ過差圧100kPaから150kPa程度であることを考えれば、ろ過差圧上昇速度が0.35kPa/日のろ過運転は薬液洗浄間隔が6ヶ月程度となり、該中空糸膜は耐汚れ性が高く、安定運転が可能と言える。   If the filtration differential pressure increase rate is about 0.35 kPa / day or less, the filtration differential pressure increase is about 60 kPa after 6 months of operation. Considering that the initial filtration differential pressure is about 20 to 30 kPa and the standard for chemical cleaning is about 100 to 150 kPa, the filtration differential pressure increase rate is 0.35 kPa / day. Thus, it can be said that the hollow fiber membrane has high stain resistance and can be stably operated.

<実施例1>
一段目膜ろ過装置として加圧型で膜面積72mの東レ株式会社製ポリフッ化ビニリデン製中空糸精密ろ過膜モジュール“HFS−2020”を1モジュール用い、二段目膜ろ過装置として東レ株式会社製ポリフッ化ビニリデン製中空糸精密ろ過膜モジュール“HFS−2020”の中空糸膜を用いて作製した膜面積22mの浸漬型中空糸膜モジュールを1モジュール用いた二段膜ろ過システムを作製した。
<Example 1>
As a first-stage membrane filtration apparatus, one module of a hollow fiber microfiltration membrane module “HFS-2020” made by polyvinylidene fluoride with a membrane area of 72 m 2 is used as a first-stage membrane filtration apparatus, and as a second-stage membrane filtration apparatus, polyfluoride produced by Toray Industries, Inc. A two-stage membrane filtration system using one module of an immersion type hollow fiber membrane module having a membrane area of 22 m 2 produced using a hollow fiber membrane of vinylidene fluoride hollow fiber microfiltration membrane module “HFS-2020” was produced.

東レ株式会社製ポリフッ化ビニリデン製中空糸精密ろ過膜モジュール“HFS−2020”の被処理水平均濁度Tと安定運転可能上限膜ろ過流束Fの関係はF=5.8T −0.55、Fと安定運転可能上限透過水回収率Rの関係はR=1−0.021Fであった。また、東レ株式会社製ポリフッ化ビニリデン製中空糸精密ろ過膜モジュール“HFS−2020”の中空糸膜を用いて作製した膜面積20mの浸漬型中空糸膜モジュールの膜供給水平均濁度Tと安定運転可能上限膜ろ過流束Fの関係はF=2.5T −0.35、Fと安定運転可能上限透過水回収率Rの関係はR=1−0.014Fであった。この二段膜ろ過システムを用いて平均濁度3度の琵琶湖水のろ過を行った。 The relationship between the treated water average turbidity T 1 of the hollow fiber microfiltration membrane module “HFS-2020” manufactured by Toray Industries, Inc. and the upper limit membrane filtration flux F 1 capable of stable operation is F 1 = 5.8 T 1 − 0.55, the relationship F 1 and stable operation can limit the permeate recovery ratio R 1 was R 1 = 1-0.021F 1. Moreover, the membrane feed water average turbidity T 2 of a submerged hollow fiber membrane module having a membrane area of 20 m 2 produced using a hollow fiber membrane of a hollow fiber microfiltration membrane module “HFS-2020” made of polyvinylidene fluoride manufactured by Toray Industries, Inc. the stable operation can relationship upper membrane filtration flux F 2 and F 2 = 2.5T 2 -0.35, the relationship F 2 and stable operation can limit the permeate recovery R 2 is R 2 = 1-0.014F 2 . Lake Biwa water with an average turbidity of 3 degrees was filtered using this two-stage membrane filtration system.

上記の式から一段目膜ろ過装置の膜ろ過流束は3.2m/日、透過水回収率は93.3%、二段目膜ろ過装置の膜ろ過流束は0.7m/日、透過水回収率は99.0%とした。この時、一段目膜ろ過装置の物理洗浄排水平均濁度、すなわち二段目膜ろ過装置の膜供給水平均濁度は45度、二段膜ろ過システムの被処理水タンクへの被処理水流入流量は230m/日、透過水タンクから流出する透過水の平均流量は229.85m/日、システム全体の透過水回収率は99.93%であった。 From the above formula, the membrane filtration flux of the first-stage membrane filtration device is 3.2 m / day, the permeate recovery rate is 93.3%, the membrane filtration flux of the second-stage membrane filtration device is 0.7 m / day, and the permeation rate The water recovery rate was 99.0%. At this time, the average turbidity of the physical washing wastewater of the first stage membrane filtration device, that is, the average turbidity of the membrane supply water of the second stage membrane filtration device is 45 degrees, the treated water flowing into the treated water tank of the second stage membrane filtration system The flow rate was 230 m 3 / day, the average flow rate of the permeate flowing out from the permeate tank was 229.85 m 3 / day, and the permeate recovery rate of the entire system was 99.93%.

運転性評価を実施した結果、一段目膜ろ過装置のろ過差圧上昇速度は0.20kPa/日、二段目膜ろ過装置は50日間ろ過差圧の上昇がなく、システムとして安定なろ過運転を行うことができた。   As a result of the operability evaluation, the filtration differential pressure increase rate of the first-stage membrane filtration device is 0.20 kPa / day, and the second-stage membrane filtration device has no increase in filtration differential pressure for 50 days. Could be done.

<比較例1>
実施例1と同様な二段膜ろ過システムにおいて、一段目膜ろ過装置の膜ろ過流束Fを3.8m/日とする以外は実施例1と同様な運転条件で二段膜ろ過システムの運転性評価を実施した。本比較例ではFが、F=5.8T −0.55から得られるFの±10%に含まれず、請求項1および6の要件を満たさないこととなる。その結果、一段目膜ろ過装置のろ過差圧上昇速度が0.65kPa/日となり、実施例1に比べてろ過差圧の上昇が早く、一段目膜ろ過装置の薬液洗浄頻度が多くなると考えられた。
<Comparative Example 1>
In a similar two-stage membrane filtration system as in Example 1, a two-stage membrane filtration system in the same operating conditions as in Example 1 except that the membrane filtration flux F 1 of the first stage membrane filtration units and 3.8 m / day A drivability evaluation was conducted. In this comparative example, F 1 is not included in ± 10% of F 1 obtained from F 1 = 5.8T 1 −0.55, and does not satisfy the requirements of claims 1 and 6. As a result, the rate of increase in the filtration differential pressure of the first-stage membrane filtration device is 0.65 kPa / day, and the increase in the filtration differential pressure is faster than in Example 1, and the frequency of the chemical cleaning of the first-stage membrane filtration device is thought to increase. It was.

<比較例2>
実施例1と同様な二段膜ろ過システムにおいて、二段目膜ろ過装置の膜面積を15m、膜ろ過流束Fを1.0m/日とする以外は実施例1と同様な運転条件で二段膜ろ過システムの運転性評価を実施した。本比較例ではFが、F=2.5T −0.35から得られるFの±10%に含まれず、請求項1および6の要件を満たさないこととなる。ここで二段目膜ろ過装置の浸漬型中空糸膜モジュールは、実施例1の浸漬型中空糸膜モジュールと同一の中空糸膜有効長、同一の中空糸膜充填率として、モジュールの直径のみを小さくして、中空糸膜の本数を減らして作製した。このため定数d、e、fは実施例1と同一であった。運転性評価の結果、二段目膜ろ過装置のろ過差圧上昇速度が1.0kPa/日となり、実施例1に比べてろ過差圧の上昇が早く、二段目膜ろ過装置の薬液洗浄頻度が多くなると考えられた。
<Comparative example 2>
In the same two-stage membrane filtration system as in Example 1, the operating conditions are the same as in Example 1 except that the membrane area of the second-stage membrane filtration device is 15 m 2 and the membrane filtration flux F 2 is 1.0 m / day. The operability evaluation of the two-stage membrane filtration system was carried out. In this comparative example, F 2 is not included in ± 10% of F 2 obtained from F 2 = 2.5T 2 −0.35, and does not satisfy the requirements of claims 1 and 6. Here, the submerged hollow fiber membrane module of the second stage membrane filtration apparatus has the same hollow fiber membrane effective length and the same hollow fiber membrane filling rate as the submerged hollow fiber membrane module of Example 1, and only the diameter of the module. It was made smaller to reduce the number of hollow fiber membranes. For this reason, the constants d, e, and f were the same as those in Example 1. As a result of the drivability evaluation, the rate of increase in the filtration differential pressure of the second stage membrane filtration apparatus was 1.0 kPa / day, and the increase in the filtration differential pressure was faster than that in Example 1, and the chemical cleaning frequency of the second stage membrane filtration apparatus was high. Was thought to increase.

<比較例3>
実施例1と同様な二段膜ろ過システムにおいて、一段目膜ろ過装置および/または二段目膜ろ過装置の膜ろ過流束F、Fを請求項1および6の要件を満たさなくするまで下げると、膜モジュール数を増やす必要があり、膜モジュール費用、設置面積、設備費用などの点から経済的でなく実施例1に比べて不利であった。
<Comparative Example 3>
In the same two-stage membrane filtration system as in Example 1, until the membrane filtration fluxes F 1 and F 2 of the first-stage membrane filtration device and / or the second-stage membrane filtration device do not satisfy the requirements of claims 1 and 6 If it is lowered, it is necessary to increase the number of membrane modules, which is not economical and disadvantageous compared to Example 1 in terms of membrane module cost, installation area, equipment cost, and the like.

<比較例4>
実施例1と同様な二段膜ろ過システムにおいて、一段目膜ろ過装置の透過水回収率Rを97.0%と高めた。本比較例ではRが、F=5.8T −0.55、およびR=1−0.021Fから得られるRの±2%に含まれず、請求項1および6の要件を満たさないこととなる。また、一段目膜ろ過装置の回収率を高めたぶん二段目膜ろ過装置の回収率を97.5%まで下げてもシステム全体の透過水回収率は99.93%を保てるため、二段目膜ろ過装置の透過水回収率を97.5%に下げた。それ以外は実施例1と全く同様な条件として二段膜ろ過システムの運転性評価を実施した。その結果、一段目膜ろ過装置のろ過差圧上昇速度が0.68kPa/日となり、実施例1に比べてろ過差圧の上昇が早かった。また、一段目膜ろ過装置の透過水回収率を高めたため、一段目膜ろ過装置の物理洗浄排水平均濁度、すなわち二段目膜ろ過装置の膜供給水平均濁度が102度となり、二段目膜ろ過装置のろ過差圧上昇速度が1.3kPa/日と高くなり安定運転ができなかった。
<Comparative example 4>
In a similar two-stage membrane filtration system as in Example 1 enhanced the permeate recovery ratio R 1 of the first stage membrane filtration units and 97.0%. R 1 in this comparative example, F 1 = 5.8T 1 -0.55, and R 1 = 1-0.021F not included in of ± 2% R 1 derived from 1, claims 1 and 6 Requirements Will not be satisfied. Also, if the recovery rate of the second stage membrane filtration device is increased to 97.5% even if the recovery rate of the first stage membrane filtration device is increased, the permeate recovery rate of the entire system can be maintained at 99.93%, The permeate recovery rate of the membrane filtration device was lowered to 97.5%. Other than that, the operability evaluation of the two-stage membrane filtration system was performed under the same conditions as in Example 1. As a result, the rate of increase in the filtration differential pressure of the first-stage membrane filtration apparatus was 0.68 kPa / day, and the increase in the filtration differential pressure was faster than that in Example 1. In addition, since the permeate recovery rate of the first stage membrane filtration apparatus was increased, the average turbidity of physical washing wastewater of the first stage membrane filtration apparatus, that is, the average turbidity of the membrane supply water of the second stage membrane filtration apparatus was 102 degrees. The rate of increase in the filtration differential pressure of the membrane filtration device was as high as 1.3 kPa / day, and stable operation was not possible.

<比較例5>
実施例1と同様な二段膜ろ過システムにおいて、一段目膜ろ過装置の透過水回収率Rを90.0%に下げた。本比較例ではR=5.8T −0.55、およびR=1−0.021Fから得られるRの±2%に含まれず、請求項1および6の要件を満たさないこととなる。また、一段目膜ろ過装置の回収率を下げたぶん二段目膜ろ過装置の回収率を99.93%まで高めないとシステム全体の透過水回収率を99.93%にできないため、二段目膜ろ過装置の透過水回収率を99.93%に高めた。それ以外は実施例1と全く同様な条件として二段膜ろ過システムの運転性評価を実施した。その結果、一段目膜ろ過装置のろ過差圧上昇速度は0.16kPa/日となり、実施例1に比べてろ過差圧の上昇が遅く安定であった。しかしながら、一段目膜ろ過装置の透過水回収率を下げたため、一段目膜ろ過装置の物理洗浄排水平均濁度、すなわち二段目膜ろ過装置の膜供給水平均濁度は31度と下がったにもかかわらず、物理洗浄が僅かしか実施できなかったため、二段目膜ろ過装置のろ過差圧上昇速度が0.9kPa/日と高くなり、実施例1に比べてろ過差圧の上昇が早く、二段目膜ろ過装置の薬液洗浄頻度が多くなると考えられた。
<Comparative Example 5>
In a similar two-stage membrane filtration system as in Example 1, it was lowered permeate recovery ratio R 1 of the first stage membrane filtration units to 90.0%. R 1 in this comparative example, F 1 = 5.8T 1 -0.55, and R 1 = 1-0.021F not included in of ± 2% R 1 derived from 1, claims 1 and 6 Requirements Will not be satisfied. In addition, if the recovery rate of the second-stage membrane filtration device is lowered to 99.93%, the permeate recovery rate of the entire system cannot be increased to 99.93%, so the second-stage membrane filtration device cannot be increased to 99.93%. The permeate recovery rate of the membrane filtration device was increased to 99.93%. Other than that, the operability evaluation of the two-stage membrane filtration system was performed under the same conditions as in Example 1. As a result, the rate of increase in the filtration differential pressure of the first-stage membrane filtration device was 0.16 kPa / day, and the increase in the filtration differential pressure was slow and stable compared to Example 1. However, since the permeate recovery rate of the first-stage membrane filtration device was lowered, the average turbidity of physical washing wastewater of the first-stage membrane filtration device, that is, the average turbidity of membrane supply water of the second-stage membrane filtration device was reduced to 31 degrees. However, since only a few physical washings could be performed, the filtration differential pressure increase rate of the second-stage membrane filtration device was as high as 0.9 kPa / day, and the increase in the filtration differential pressure was faster than in Example 1, The chemical cleaning frequency of the second stage membrane filtration device was considered to increase.

Figure 2006272218
Figure 2006272218

本発明の二段膜ろ過システムは、飲料水製造のための浄水処理、工業用水製造、下水・排水処理、海水淡水化の前処理などに利用することができる。   The two-stage membrane filtration system of the present invention can be used for water purification treatment for drinking water production, industrial water production, sewage / drainage treatment, pretreatment for seawater desalination, and the like.

本発明に係る二段膜ろ過システムの一例。An example of the two-stage membrane filtration system which concerns on this invention.

符号の説明Explanation of symbols

1 被処理水タンク
2 一段目膜ろ過装置のポンプ
3 一段目膜ろ過装置
4 二段目膜ろ過装置
5 二段目膜ろ過装置のポンプ
6 透過水タンク
7 逆洗用ポンプ
8 バルブ
DESCRIPTION OF SYMBOLS 1 Water tank to be treated 2 Pump of first stage membrane filtration device 3 First stage membrane filtration device 4 Second stage membrane filtration device 5 Pump of second stage membrane filtration device 6 Permeate tank 7 Backwash pump 8 Valve

Claims (12)

1)固有のパラメータa,b,cを有する限外ろ過膜モジュールまたは精密ろ過膜モジュールを具備する一段目ろ過手段、
2)前記一段目ろ過手段の透過水側から被処理水側への送水することで、前記一段目ろ過手段を逆洗する物理洗浄手段、
3)前記物理洗浄手段による洗浄時に排出された物理洗浄排水を膜ろ過する、固有のパラメータd,e,fを有する限外ろ過膜モジュールまたは精密ろ過膜モジュールを具備する二段目ろ過手段、
4)前記一段目ろ過手段で膜ろ過する被処理水の平均濁度をT,前記二段目ろ過手段で膜ろ過する被処理水の平均濁度をTとしたとき、前記一段目ろ過手段における膜ろ過流束Fおよび透過水回収率R、ならびに前記二段目ろ過手段における膜ろ過流束Fおよび透過水回収率Rを、下式
=aT −b
=dT −e
=1−cF
=1−fF
を実質的に満たすように膜ろ過条件を制御する手段
を有する二段膜ろ過システムであって、前記限外ろ過膜モジュールまたは精密ろ過膜モジュールに固有のパラメータa、b、c、d、e、fが
1.5≦a≦10
0.3≦b≦1
0.005≦c≦0.04
1.5≦d≦6
0.1≦e≦1
0.005≦f≦0.02
である二段膜ろ過システム。
1) First-stage filtration means comprising an ultrafiltration membrane module or a microfiltration membrane module having unique parameters a, b, c
2) Physical washing means for backwashing the first-stage filtration means by feeding water from the permeate side to the treated water side of the first-stage filtration means,
3) A second-stage filtration means comprising an ultrafiltration membrane module or a microfiltration membrane module having specific parameters d, e, and f, which membrane-filters the physical washing wastewater discharged during washing by the physical washing means,
4) When the average turbidity of the water to be treated filtered by the first stage filtration means is T 1 and the average turbidity of the water to be treated filtered by the second stage filtration means is T 2 , the first stage filtration is performed. The membrane filtration flux F 1 and permeate recovery rate R 1 in the means, and the membrane filtration flux F 2 and permeate recovery rate R 2 in the second-stage filtration means are expressed by the following formula: F 1 = aT 1 -b
F 2 = dT 2 −e
R 1 = 1-cF 1
R 2 = 1−fF 2
A two-stage membrane filtration system having means for controlling membrane filtration conditions so as to substantially satisfy the parameters a, b, c, d, e, unique to the ultrafiltration membrane module or the microfiltration membrane module. f is 1.5 ≦ a ≦ 10
0.3 ≦ b ≦ 1
0.005 ≦ c ≦ 0.04
1.5 ≦ d ≦ 6
0.1 ≦ e ≦ 1
0.005 ≦ f ≦ 0.02
Is a two-stage membrane filtration system.
二段膜ろ過システム全体の透過水回収率Rを99.9%以上に制御する手段を有する請求項1に記載の二段膜ろ過システム。 The two-stage membrane filtration system according to claim 1, comprising means for controlling the permeate recovery rate R of the entire two-stage membrane filtration system to 99.9% or more. 前記二段目膜ろ過装置の膜モジュールが浸漬型膜モジュールである請求項1または2に記載の二段膜ろ過システム。 The two-stage membrane filtration system according to claim 1 or 2, wherein the membrane module of the second-stage membrane filtration apparatus is an immersion type membrane module. 前記一段目膜ろ過装置の膜モジュールが加圧型膜モジュールである請求項1〜3のいずれかに記載の二段膜ろ過システム。 The two-stage membrane filtration system according to any one of claims 1 to 3, wherein the membrane module of the first-stage membrane filtration device is a pressure type membrane module. 前記一段目膜ろ過装置の膜モジュールが全量ろ過方式である請求項4に記載の二段膜ろ過システム。 The two-stage membrane filtration system according to claim 4, wherein the membrane module of the first-stage membrane filtration apparatus is a total filtration system. 1)その固有のパラメータa,b,cが、
1.5≦a≦10
0.3≦b≦1
0.005≦c≦0.04
である限外ろ過膜モジュールまたは精密ろ過膜モジュールからなる一段目膜ろ過装置で、平均濁度Tの被処理水を、膜ろ過流束Fで透過水回収率をRで膜ろ過する一段目ろ過工程、
2)前記一段目膜ろ過装置の透過水側から被処理水側に送水し、前記一段目膜ろ過装置を逆洗する工程を有する物理洗浄工程、
3)その固有のパラメータd,e,fが、
1.5≦d≦6
0.1≦e≦1
0.005≦f≦0.02
である限外ろ過膜モジュールまたは精密ろ過膜モジュールからなる二段目膜ろ過装置で、前記物理洗浄工程から排出された平均濁度Tの物理洗浄排水を、膜ろ過流束Fで透過水回収率をRで膜ろ過する二段目ろ過工程
を有する二段膜ろ過システムの運転方法であって、前記平均濁度T,T、前記膜ろ過流束F,F、および前記透過水回収率R,Rを実質的に、
=aT −b
=dT −e
=1−cF
=1−fF
となるように運転して、前記一段目ろ過工程および前記二段目ろ過工程から透過水を回収する二段膜ろ過システムの運転方法。
1) The unique parameters a, b, c are
1.5 ≦ a ≦ 10
0.3 ≦ b ≦ 1
0.005 ≦ c ≦ 0.04
The membrane to be treated having an average turbidity T 1 is subjected to membrane filtration with a membrane filtration flux F 1 and a permeate recovery rate of R 1. First stage filtration process,
2) Physical washing step including a step of feeding water from the permeate side of the first-stage membrane filtration device to the treated water side and backwashing the first-stage membrane filtration device,
3) The unique parameters d, e, f are
1.5 ≦ d ≦ 6
0.1 ≦ e ≦ 1
0.005 ≦ f ≦ 0.02
In the second-stage membrane filtration apparatus comprising an ultrafiltration membrane module or a microfiltration membrane module, the physical washing wastewater having an average turbidity T 2 discharged from the physical washing step is permeated with a membrane filtration flux F 2. An operation method of a two-stage membrane filtration system having a second-stage filtration step of membrane filtration with R 2 , wherein the average turbidity T 1 , T 2 , the membrane filtration fluxes F 1 , F 2 , and The permeate recovery rates R 1 and R 2 are substantially
F 1 = aT 1 -b
F 2 = dT 2 −e
R 1 = 1-cF 1
R 2 = 1−fF 2
The operation method of the two-stage membrane filtration system which is operated so that the permeated water is recovered from the first-stage filtration step and the second-stage filtration step.
二段膜ろ過システム全体の透過水回収率Rが99.9%以上の請求項6に記載の二段膜ろ過システムの運転方法。 The operation method of the two-stage membrane filtration system according to claim 6, wherein the permeate recovery rate R of the entire two-stage membrane filtration system is 99.9% or more. 前記二段目膜ろ過装置の膜モジュールが浸漬型膜モジュールである請求項6または7に記載の二段膜ろ過システムの運転方法。 The operation method of the two-stage membrane filtration system according to claim 6 or 7, wherein the membrane module of the second-stage membrane filtration apparatus is an immersion type membrane module. 前記一段目膜ろ過装置の膜モジュールが加圧型膜モジュールである請求項6〜8のいずれかに記載の二段膜ろ過システムの運転方法。 The operation method of the two-stage membrane filtration system according to any one of claims 6 to 8, wherein the membrane module of the first-stage membrane filtration apparatus is a pressure type membrane module. 前記一段目膜ろ過装置の膜モジュールが全量ろ過方式である請求項9に記載の二段膜ろ過システムの運転方法。 The operation method of the two-stage membrane filtration system according to claim 9, wherein the membrane module of the first-stage membrane filtration apparatus is a total filtration system. 限外ろ過膜モジュールまたは精密ろ過膜モジュールに固有のパラメータであるa、b、c、d、e、fが、
5≦a≦8
0.4≦b≦0.8
0.016≦c≦0.03
2.5≦d<5
0.2≦e<0.4
0.01≦f<0.016
であることを特徴とする請求項1〜5に記載の二段膜ろ過システム。
Parameters a, b, c, d, e, and f inherent to the ultrafiltration membrane module or microfiltration membrane module are
5 ≦ a ≦ 8
0.4 ≦ b ≦ 0.8
0.016 ≦ c ≦ 0.03
2.5 ≦ d <5
0.2 ≦ e <0.4
0.01 ≦ f <0.016
The two-stage membrane filtration system according to claim 1, wherein:
限外ろ過膜モジュールまたは精密ろ過膜モジュールに固有のパラメータであるa、b、c、d、e、fが、
5≦a≦8
0.4≦b≦0.8
0.016≦c≦0.03
2.5≦d<5
0.2≦e<0.4
0.01≦f<0.016
であることを特徴とする請求項6〜10に記載の二段膜ろ過システムの運転方法。
Parameters a, b, c, d, e, and f inherent to the ultrafiltration membrane module or microfiltration membrane module are
5 ≦ a ≦ 8
0.4 ≦ b ≦ 0.8
0.016 ≦ c ≦ 0.03
2.5 ≦ d <5
0.2 ≦ e <0.4
0.01 ≦ f <0.016
The operation method of the two-stage membrane filtration system according to claim 6, wherein the two-stage membrane filtration system is an operation method.
JP2005097269A 2005-03-30 2005-03-30 Two-stage membrane filtration system and operation method of two-stage membrane filtration system Pending JP2006272218A (en)

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KR101496729B1 (en) * 2014-01-07 2015-03-02 주식회사 포스코건설 Two stage membrane filtration apparatus and method for water treatment using the same
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7720658B2 (en) * 2005-06-02 2010-05-18 Institut Francais Du Petrole Method of upscaling absolute permeabilities to construct a flow simulation model
JP2007307469A (en) * 2006-05-17 2007-11-29 Fuji Electric Holdings Co Ltd Method for treating water
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KR101418738B1 (en) * 2012-07-03 2014-07-11 대림산업 주식회사 Immersion type-pressure type hybrid membrane filtration system
KR101496729B1 (en) * 2014-01-07 2015-03-02 주식회사 포스코건설 Two stage membrane filtration apparatus and method for water treatment using the same
KR101656180B1 (en) * 2015-03-23 2016-09-08 김남호 Silica composition containing Manufacture of drinking water Purification equipment

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