JP4959157B2

JP4959157B2 - Circulating nanofiltration test apparatus and circulating nanofiltration test method

Info

Publication number: JP4959157B2
Application number: JP2005210378A
Authority: JP
Inventors: 雅喜伊藤; 司品田; 直輝太田; 直秀松本; 隆仁杉本; 弘幸古屋; 亮太高木
Original assignee: Kubota Corp; Toray Industries Inc; Suido Kiko Kaisha Ltd; Swing Corp
Current assignee: Kubota Corp; Toray Industries Inc; Suido Kiko Kaisha Ltd; Swing Corp
Priority date: 2005-07-20
Filing date: 2005-07-20
Publication date: 2012-06-20
Anticipated expiration: 2025-07-20
Also published as: JP2007021440A

Description

この発明は、例えば浄水場に設置しようとする一過型多段ナノろ過実施設の処理機能を予測する装置および方法に関する。 The present invention relates to an apparatus and a method for predicting a processing function of a temporary multi-stage nanofiltration implementation facility to be installed in a water purification plant, for example.

従来、水道の原水には富栄養化、病原性微生物などの自然発生的な物質の他に、農薬、中性洗剤などの人為的な物質が含まれている。過去には、病原性微生物であるクリプトスポリジウムによる集団感染が発生したこともある。この対策として、浄水場には原水をろ過膜によってろ過する膜ろ過施設が導入され、原水から懸濁物質ばかりでなく細菌類、藻類、原虫類などが確実に除去されている。このような膜ろ過施設に使用されている膜として、サイズの大きな方から順に精密ろ過膜、限外ろ過膜、ナノろ過膜、および逆浸透膜が知られている。これらの膜のうち、精密ろ過膜および限外ろ過膜は細菌類を極めて高度に除去できるが、農薬や臭気物質などは十分に除去できないものとなっている。このため、精密ろ過膜や限外ろ過膜を用いて処理したろ過水は、オゾンや活性炭によって更に処理することが必要となっている。 Conventionally, raw water for tap water contains artificial substances such as agricultural chemicals and neutral detergents in addition to eutrophication and naturally occurring substances such as pathogenic microorganisms. In the past, mass infections have occurred with Cryptosporidium, a pathogenic microorganism. As a countermeasure, a membrane filtration facility that filters raw water through a filtration membrane has been introduced to the water purification plant, and not only suspended substances but also bacteria, algae, and protozoa are reliably removed from the raw water. As membranes used in such membrane filtration facilities, microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and reverse osmosis membranes are known in order from the largest size. Among these membranes, microfiltration membranes and ultrafiltration membranes can remove bacteria to a very high degree, but cannot sufficiently remove agricultural chemicals and odorous substances. For this reason, it is necessary to further treat the filtered water treated with a microfiltration membrane or an ultrafiltration membrane with ozone or activated carbon.

これに対し、ナノろ過膜を用いた膜ろ過施設はオゾンや活性炭による処理が不要とされ、オゾン・活性炭処理の代替として位置付けられている。このようなナノろ過膜を用いた膜ろ過施設の多くは、小規模な施設を除いて、供給水を循環させない所謂一過型多段ナノろ過施設とされている。この種の一過型多段ナノろ過施設では、複数の膜モジュールがバンク式またはツリー式に一過型として配置され、第１バンクの膜モジュールで生成された濃縮水が第２バンクの膜モジュールに供給され、回収率の向上が図られている。そして、より高い回収率を目指す場合には第２バンクの膜モジュールの濃縮水が第３バンクの膜モジュールに供給され、更なる高い回収率を目指す場合には更なるバンクが追加されて同様に処理されている。 On the other hand, membrane filtration facilities using nanofiltration membranes do not require treatment with ozone or activated carbon, and are positioned as alternatives to ozone / activated carbon treatment. Many membrane filtration facilities using such nanofiltration membranes are so-called single-stage multi-stage nanofiltration facilities that do not circulate supply water except for small-scale facilities. In this type of single-stage multi-stage nanofiltration facility, a plurality of membrane modules are arranged in a single-bank or tree-type, and the concentrated water generated by the first bank membrane module is used as the second bank membrane module. It is supplied and the recovery rate is improved. And when aiming for a higher recovery rate, the concentrated water from the membrane module of the second bank is supplied to the membrane module of the third bank, and when aiming for a higher recovery rate, additional banks are added in the same manner. Has been processed.

なお、上記先行技術は当業者一般に知られた技術であって、文献公知発明に係るものではない。 The above prior art is a technique generally known to those skilled in the art, and does not relate to a known literature invention.

上述の一過型多段ナノろ過施設の処理機能は運転圧力、供給水濃度、供給水温度などの処理機能影響因子によって異なるので、一過型多段ナノろ過施設の処理機能を予測するためには、一過型多段ナノろ過施設と同じ試験施設を用意する必要があり、研究開発コスト、施設コスト、運転管理コストなどが極めて高くなっている。 Since the processing function of the above-mentioned transient multi-stage nanofiltration facility differs depending on the processing function influencing factors such as operating pressure, supply water concentration, and supply water temperature, in order to predict the processing function of the transient multi-stage nanofiltration facility, It is necessary to prepare the same test facility as the transient multi-stage nanofiltration facility, and the research and development cost, facility cost, operation management cost, etc. are extremely high.

この発明は、上述のような課題を解決するためになされたもので、第１の目的は、簡素な構成で一過型多段ナノろ過実施設の処理機能を予測できる循環型ナノろ過試験装置を得るものである。
また、第２の目的は、簡素な構成の循環型ナノろ過試験装置によって一過型多段ナノろ過実施設の処理機能を予測できる処理機能予測方法を得るものである。 The present invention has been made to solve the above-described problems, and a first object is to provide a circulating nanofiltration test apparatus capable of predicting the processing function of a transient multistage nanofiltration implementation with a simple configuration. To get.
Moreover, the 2nd objective is to obtain the processing function prediction method which can predict the processing function of a temporary multistage nanofiltration implementation by the circulation type nanofiltration test apparatus of simple structure.

この発明に係る循環型ナノろ過試験装置は、前処理された供給水をナノろ過する一過型多段ナノろ過実施設の処理機能を予測する循環型ナノろ過試験装置において、前記供給水を貯留する供給水槽、前記供給水をナノろ過する上流側膜エレメント、前記供給水槽から該上流側膜エレメントへ前記供給水を供給する供給水管、該供給水管に設けられた供給ポンプ、前記上流側膜エレメントの濃縮水をナノろ過する後流側膜エレメント、該後流側膜エレメントへ前記上流側膜エレメントの濃縮水を導く上流側濃縮水管、前記後流側膜エレメントで生じた濃縮水を系外に排出する後流側濃縮水管、前記上流側膜エレメントと前記後流側膜エレメントのろ過水を貯留するろ過水槽、前記上流側膜エレメントのろ過水をろ過水槽へ導く上流側ろ過水管、前記後流側膜エレメントのろ過水をろ過水槽へ導く後流側ろ過水管、および前記後流側膜エレメントの濃縮水を前記供給水管の前記供給ポンプより上流に循環させる循環水管を備えたことを特徴とする循環型ナノろ過試験装置である。 The circulation type nanofiltration test apparatus according to the present invention stores the supply water in the circulation type nanofiltration test apparatus that predicts the processing function of a transient multi-stage nanofiltration implementation that nanofilters pretreated supply water. A feed water tank, an upstream membrane element that nano-filters the feed water, a feed water pipe that feeds the feed water from the feed water tank to the upstream membrane element, a feed pump provided in the feed water pipe, and an upstream membrane element A downstream membrane element for nanofiltration of the concentrated water, an upstream concentrated water pipe for leading the concentrated water of the upstream membrane element to the downstream membrane element, and the concentrated water generated in the downstream membrane element is discharged out of the system The upstream-side concentrated water pipe, the upstream-side membrane element and the filtered water tank for storing the filtrate of the downstream-side membrane element, the upstream-side filtered water pipe for guiding the filtered water of the upstream-side membrane element to the filtered water tank, The apparatus has a wake-side filtered water pipe that guides the filtrate of the wake-side membrane element to a filtrate tank, and a circulating water pipe that circulates the concentrated water of the wake-side membrane element upstream from the supply pump of the supply water pipe. This is a circulation type nanofiltration test apparatus.

この発明に係る循環型ナノろ過試験方法は、請求項１に記載の循環型ナノろ過試験装置を用いて、供給水濃度、水回収率、および物質除去率の関係を前記一過型多段ナノろ過実施設の濃度予測式に適用することによって前記一過型多段ナノろ過実施設の処理機能を予測する循環型ナノろ過試験方法において、供給水濃度をＣ _ｆｎ、水回収率をｒ _ｎ、物質除去率をＲ _ｎとした場合に、前記一過型多段ナノろ過実施設のｎ番目の膜エレメントにおける濃縮水濃度Ｃ _ｂｎの予測式は、
Ｃ_bn＝Ｃ_fn・{ｒ_n(１−ｒ_n)−２}／{ｒ_n(１＋Ｒ_n)−２}
であり、ろ過水濃度Ｃ _pn の予測式は
Ｃ_pn＝Ｃ_fn・(ｒ_n−２)(１−Ｒ_n)／{ｒ_n(１＋Ｒ_n)−２}
であることを特徴とする循環型ナノろ過試験方法である。 The circulation type nanofiltration test method according to the present invention uses the circulation type nanofiltration test apparatus according to claim 1 to determine the relationship between the supply water concentration, the water recovery rate, and the substance removal rate. in recycling nanofiltration test method for predicting the processing function of the transient multistage nanofiltration actual plant by applying to a concentration prediction equation of actual plant, the feed water concentration C _fn, the water recovery rate r _n, substance removing When the rate is R _n , the prediction formula of the concentrated water concentration C _bn in the n-th membrane element of the transient multi-stage nanofiltration _{implementation} is:
C _bn = C _fn · {r _n (1-r _n ) -2} / {r _n (1 + R _n ) -2}
And the prediction formula of the filtrate concentration C _pn is C _pn = C _fn · (r _n −2) (1−R _n ) / {r _n (1 + R _n ) −2}
It is a circulation type nanofiltration test method characterized by being.

この発明は、一過型多段ナノろ過実施設の任意の箇所の少なくとも１つの膜エレメントの処理機能影響因子を循環型ナノろ過試験装置によって再現して水回収率と物質除去率を求めることにより、一過型多段ナノろ過実施設の濃度を理論的に算出できるので、一過型多段ナノろ過実施設またはそれに相当する装置を用意することなく、一過型多段ナノろ過実施設の処理機能を予測できる。そして、一過型多段ナノろ過実施設の処理機能を予測するために一過型多段ナノろ過実施設またはそれに相当する装置を用意する必要がないので、研究開発コスト、設備コスト、運転管理コストなどを大幅に削減できる。 This invention reproduces the processing function influencing factor of at least one membrane element at an arbitrary location of the transient multi-stage nanofiltration implementation facility by a circulation type nanofiltration test apparatus to obtain a water recovery rate and a substance removal rate, Since the concentration of the single-stage multi-stage nanofiltration facility can be calculated theoretically, the processing function of the single-stage multi-stage nanofiltration facility can be predicted without preparing a single-stage multi-stage nanofiltration facility or an equivalent device. it can. And since it is not necessary to prepare a single-stage multi-stage nanofiltration facility or equivalent equipment to predict the processing function of the single-stage multi-stage nanofiltration facility, research and development costs, equipment costs, operation management costs, etc. Can be greatly reduced.

実施の形態１．
図１は、例えば浄水場の一過型（ツリー型）多段ナノろ過実施設の処理機能（処理性または性能）を実証実験するために用意した一過型多段ナノろ過装置１（以降、多段型装置１という）を示すものである。図２は、多段型装置１の処理機能を予測（評価）するための循環型ナノろ過試験装置２（以降、循環型装置２という）を示すものである。浄水場は、基本的に一過型多段ナノろ過実施設と消毒施設から構成され、必要に応じて前処理施設、後処理施設、排水処理施設などが追加される。この実施の形態１における多段型装置１と循環型装置２に供給する供給水は、前処理施設で精密ろ過膜によって前処理したものとするのが好ましい。 Embodiment 1 FIG.
FIG. 1 shows, for example, a single-stage multi-stage nanofiltration device 1 (hereinafter referred to as a multi-stage type) prepared for demonstrating the treatment function (treatment performance or performance) of a single-stage (tree type) multi-stage nanofiltration facility for water purification plants. Device 1). FIG. 2 shows a circulating nanofiltration test apparatus 2 (hereinafter referred to as a circulating apparatus 2) for predicting (evaluating) the processing function of the multistage apparatus 1. The water purification plant basically consists of a single-stage multi-stage nanofiltration facility and a disinfection facility. Pre-treatment facilities, post-treatment facilities, waste water treatment facilities, etc. are added as necessary. The feed water supplied to the multistage apparatus 1 and the circulation apparatus 2 in the first embodiment is preferably pretreated with a microfiltration membrane in a pretreatment facility.

なお、この実施の形態１でいう「一過型多段ナノろ過実施設」という言葉は浄水場に設置しようとする実際の一過型多段ナノろ過施設のことを意味し、一般に「施設」という言葉を「設備」と表現することもある。また、以降においては多段型装置１を大型ナノろ過装置とよぶこともあり、循環型装置２を小型ナノろ過装置とよぶこともある。 In addition, the term “one-step multi-stage nanofiltration implementation facility” in Embodiment 1 means an actual single-stage multi-stage nanofiltration facility to be installed in a water purification plant, and generally the term “facility”. Is sometimes referred to as “equipment”. In the following, the multistage apparatus 1 is sometimes referred to as a large nanofiltration apparatus, and the circulation apparatus 2 is sometimes referred to as a small nanofiltration apparatus.

図１に示すように、多段型装置１は一過型多段ナノろ過実施設と同様なものとしてあり、バンク構成を直列４段とし、ベッセル構成を８−４−２−１としてある。すなわち、多段型装置１は第１（１ｓｔ）バンク１１、第２（２ｎｄ）バンク１２、第３（３ｒｄ）バンク１３、および第４（４ｔｈ）バンク１４から構成してある。第１バンク１１では、ナノろ過膜を構成する５つの同様な膜エレメント１５をベッセル（ハウジングまたはケーシング）１６に収容してなる８つの膜モジュール１７を並列配置してある。第２バンク１２では同様な膜モジュール１７を４列に並列配置し、第３バンク１３では同様な膜モジュール１７を２列に並列配置し、第４バンク１４では同様な膜モジュール１７を１つだけ配置してある。 As shown in FIG. 1, the multistage apparatus 1 is the same as the one-stage multistage nanofiltration implementation, and has a bank configuration of four stages in series and a vessel configuration of 8-4-2-1. That is, the multi-stage device 1 includes a first (1st) bank 11, a second (2nd) bank 12, a third (3rd) bank 13, and a fourth (4th) bank 14. In the first bank 11, eight membrane modules 17 in which five similar membrane elements 15 constituting a nanofiltration membrane are accommodated in a vessel (housing or casing) 16 are arranged in parallel. In the second bank 12, similar membrane modules 17 are arranged in parallel in four rows, in the third bank 13, similar membrane modules 17 are arranged in two rows, and in the fourth bank 14, only one similar membrane module 17 is arranged. It is arranged.

他方、循環型装置２は、多段型装置１の処理機能に影響を及ぼすと認められる因子（処理機能影響因子）を再現するものとしてある。この処理機能影響因子には、水量収支、運転圧力、供給水水質、供給水温度、浸透圧、溶質濃度などを含めることができる。 On the other hand, the circulation type device 2 reproduces a factor (processing function influence factor) recognized to affect the processing function of the multistage type device 1. The treatment function affecting factors can include water balance, operating pressure, supply water quality, supply water temperature, osmotic pressure, solute concentration, and the like.

図２に示すように、循環型装置２は、多段型装置１の任意の箇所（例えば図１において楕円で囲んだ４つの箇所のうちの１つ）における少なくとも１つの膜エレメント１５（例えば第1バンク１１の第１、第２の膜エレメント１５、１５）に相当する２つの上流側膜エレメント２１、後流側膜エレメント２１を備えている。なお、図１において楕円で囲んだ４つの箇所は、後述する実施例２において対象となる膜エレメント１５を指しており、循環型装置２に用いる膜エレメント２１は、多段型装置１の膜エレメント１５の位置や数に限定されるものではない。 As shown in FIG. 2, the circulation type apparatus 2 includes at least one membrane element 15 (for example, the first element) at an arbitrary position of the multistage apparatus 1 (for example, one of four positions surrounded by an ellipse in FIG. 1). Two upstream side membrane elements 21 corresponding to the first and second membrane elements 15, 15) of the bank 11 and the wake side membrane element 21 are provided. In FIG. 1, four points surrounded by an ellipse indicate the target membrane element 15 in Example 2 described later, and the membrane element 21 used in the circulation type device 2 is the membrane element 15 of the multistage device 1. It is not limited to the position or number.

循環型装置２の上流側膜エレメント２１および後流側膜エレメント２１は、それぞれ上流側ベッセル２２および後流側ベッセル２２に収容し、膜モジュール２３としてある。循環型装置２には、例えば前処理施設からの原水を貯留して上流側膜エレメント２１に供給するための供給水槽２４を用意してある。この供給水槽２４内の供給水は、供給水管２５と供給ポンプ２６によって上流側の膜エレメント２１に流入させるようにしてある。双方の膜エレメント２１、２１でろ過したろ過水は、上流側ろ過水管２７、後流側ろ過水管２７を介してろ過水槽２８に導くようにしてある。上流側の膜エレメント２１で生じた濃縮水は濃縮水管２９によって後流側の膜エレメント２１に導くようにし、後流側の膜エレメント２１で生じた濃縮水は濃縮水管３０を介して系外に排出するようにしてある。そして、後流側の膜エレメント２１の濃縮水の一部または全部は、循環水管３１を介して供給ポンプ２６の上流側の供給水管２５に循環させるようにしてある。 The upstream side membrane element 21 and the downstream side membrane element 21 of the circulation type device 2 are accommodated in the upstream side vessel 22 and the downstream side vessel 22, respectively , to form a membrane module 23. In the circulation type apparatus 2, for example, a supply water tank 24 for storing raw water from a pretreatment facility and supplying it to the upstream membrane element 21 is prepared. The supply water in the supply water tank 24 is made to flow into the upstream membrane element 21 by the supply water pipe 25 and the supply pump 26. The filtered water filtered by both the membrane elements 21 and 21 is guided to the filtered water tank 28 through the upstream filtered water pipe 27 and the downstream filtered water pipe 27. The concentrated water generated in the upstream membrane element 21 is guided to the downstream membrane element 21 by the concentrated water pipe 29, and the concentrated water generated in the downstream film element 21 is discharged to the outside of the system via the concentrated water pipe 30. It is supposed to be discharged. A part or all of the concentrated water of the downstream membrane element 21 is circulated to the supply water pipe 25 on the upstream side of the supply pump 26 via the circulation water pipe 31.

なお、上述の供給水槽２４およびろ過水槽２８は循環型装置２に必須のものではなく、多段型装置１の供給水源やろ過水槽でそれぞれ代用させることができる。 In addition, the above-mentioned supply water tank 24 and the filtration water tank 28 are not essential for the circulation type apparatus 2, and can be substituted by the supply water source and the filtration water tank of the multistage apparatus 1, respectively.

ここで、多段型装置１のｎ番目の膜エレメント１５における水回収率、物質除去率、ろ過水量、濃縮水量、累積システム水回収率、濃縮水濃度、ろ過水濃度は図３を参照して以下のように定義する。
ｎ番目の膜エレメント１５におけるエレメント水回収率ｒ_n；
ｒ_n＝Ｑ_pn／Ｑ_fn ・・・（式１）
ｎ番目の膜エレメント１５におけるエレメント物質除去率Ｒ_n；
Ｒ_n＝１−Ｃ_pn／{(Ｃ_fn＋Ｃ_bn)／２} ・・・（式２）
ｎ番目の膜エレメント１５のろ過水量Ｑ_pn；
Ｑ_pn＝Ｑ_fn・ｒ_n ・・・（式３）
ｎ番目の膜エレメント１５における濃縮水量Ｑ_bn；
Ｑ_bn＝Ｑ_fn・(１−ｒ_n) ・・・（式４）
ｎ番目の膜エレメント１５までの累積システム水回収率ｒ_sys；
ｒ_sys＝１／Ｑ_f1・ΣＱ_pn(ｎ＝１〜ｎ) ・・・（式５）
ｎ番目の膜エレメント１５における濃縮水濃度Ｃ_bn；
Ｃ_bn＝Ｃ_fn・{ｒ_n(１−ｒ_n)−２}／{ｒ_n(１＋Ｒ_n)−２} ・・・（式６）
ｎ番目の膜エレメント１５におけるろ過水濃度Ｃ_pn；
Ｃ_pn＝Ｃ_fn・(ｒ_n−２)(１−Ｒ_n)／{ｒ_n(１＋Ｒ_n)−２} ・・・（式７）
ただし、Ｃ_fnは供給水濃度とする。 Here, the water recovery rate, substance removal rate, filtered water amount, concentrated water amount, cumulative system water recovery rate, concentrated water concentration, filtered water concentration in the n-th membrane element 15 of the multistage apparatus 1 are as follows with reference to FIG. Define as follows.
element water recovery rate r _n in the n-th membrane element 15;
r _n = Q _pn / Q _fn (Formula 1)
Element substance removal rate R _{n in the nth} membrane element 15;
R _n = 1−C _pn / {(C _fn + C _bn ) / 2} (Formula 2)
the amount of filtered water Q _{pn of the} n-th membrane element 15;
Q _pn = Q _fn · r _n (Formula 3)
the amount of concentrated water Q _bn in the nth membrane element 15;
Q _bn = Q _fn · (1-r _n ) (Formula 4)
cumulative system water recovery rate r _sys up to the n th membrane element 15;
r _sys = 1 / Q _f1 · ΣQ _pn (n = 1 to n) (Formula 5)
concentrated water concentration C _bn in the nth membrane element 15;
C _bn = C _fn · {r _n (1-r _n ) -2} / {r _n (1 + R _n ) -2} (Formula 6)
the filtrate concentration C _pn in the nth membrane element 15;
C _pn = C _fn · (r _n −2) (1−R _n ) / {r _n (1 + R _n ) −2} (Expression 7)
However, C _fn is the supply water concentration.

そして、循環型装置２の循環水量比、水回収率、物質除去率、供給水量、濃縮水量、ろ過水量、濃縮排水量、循環水量、水回収率、供給水濃度、濃縮水濃度、ろ過水濃度は図４を参照して以下のように定義する。
循環水量比ａ；
ａ＝Ｑ_r／Ｑ₀ ・・・（式８）
エレメント水回収率ｒ；
ｒ＝Ｑ_p／Ｑ_f ・・・（式９）
エレメント物質除去率Ｒ；
Ｒ＝１−Ｃ_p／{(Ｃ_f＋Ｃ_b)／２} ・・・（式１０）
膜供給水量Ｑ_f；
Ｑ_f＝Ｑ₀・(１＋ａ) ・・・（式１１）
濃縮水量Ｑ_b；
Ｑ_b＝Ｑ₀・(１＋ａ)(１−ｒ) ・・・（式１２）
ろ過水量Ｑ_p；
Ｑ_p＝Ｑ₀・(１＋ａ)ｒ・・・（式１３）
濃縮排水量Ｑ_d；
Ｑ_d＝Ｑ₀−Ｑ₀・(１＋ａ)ｒ・・・（式１４）
循環水量Ｑ_r；
Ｑ_r＝ａ・Ｑ₀ ・・・（式１５）
水回収率ｒ_sys；
ｒ_sys＝１−(１＋ａ)ｒ・・・（式１６）
膜供給水濃度Ｃ_f；
Ｃ_f＝Ｃ₀・{ｒ(１＋Ｒ)−２}／{ｒ(１＋(１＋２ａ)Ｒ）−２}・・・（式１７）
濃縮水濃度Ｃ_b；
Ｃ_b＝Ｃ₀・{ｒ(１−Ｒ)−２}／{ｒ(１＋(１＋２ａ)Ｒ)−２}・・・（式１８）
ろ過水濃度Ｃ_p；
Ｃ_p＝Ｃ₀・(ｒ−２)(１−Ｒ)／{ｒ(１＋(１＋２ａ)Ｒ)−２}・・・（式１９） The circulating water volume ratio of circulating apparatus 2, water recovery, object substance removal rate, feed water, concentrated water, filtered water, concentrated water discharge amount, the circulation water, water recovery, feed water concentration, concentrated water concentration, the filtered water concentration Is defined as follows with reference to FIG.
Circulating water volume ratio a;
a = Q _r / Q ₀ (Expression 8)
Element water recovery rate r;
_{_{r = Q p / Q f ···}} ( Equation 9)
Element substance removal rate R;
R = 1−C _p / {(C _f + C _b ) / 2} (Equation 10)
Membrane supply water volume Q _f ;
Q _f = Q ₀ · (1 + a) (Formula 11)
Concentrated water amount Q _b ;
Q _b = Q ₀ · (1 + a) (1-r) (Formula 12)
Filtered water volume Q _p ;
Q _p = Q ₀ · (1 + a) r (Formula 13)
Concentrated wastewater Q _d ;
Q _d = Q ₀ −Q ₀ · (1 + a) r (Expression 14)
Circulating water volume Q _r ;
Q _r = a · Q ₀ (Formula 15)
Water recovery rate r _sys ;
r _sys = 1− (1 + a) r (Expression 16)
Membrane feed water concentration C _f ;
C _f = C _0. {R (1 + R) -2} / {r (1+ (1 + 2a) R) -2} (Expression 17)
Concentrated water concentration C _b ;
_{_{C b = C 0 · {r}} (1-R) -2} / {r (1+ (1 + 2a) R) -2} ··· ( Formula 18)
Filtrate concentration C _p ;
_{_{C p = C 0 · (r}} -2) (1-R) / {r (1+ (1 + 2a) R) -2} ··· ( 19)

以上により、多段型装置１と循環型装置２では、エレメント水回収率とエレメント物質除去率が決まれば、濃縮水濃度、ろ過水濃度などを求めることができる。具体的な数値で例えれば、多段型装置１の例えば第２バンク１２の第１の膜エレメント１５に流入する供給水量を１００とし、そのエレメント水回収率を１０％と仮定すると、第２バンク１２の第１〜第５の膜エレメント１５でのろ過水量はそれぞれ１０、９、約８、約７．３、約６．５となり、次位の膜エレメント１５に流入する濃縮水量は順次に９０、８１、約７３、約６５となる。したがって、第１〜第５の膜エレメント１５のろ過水量の累積（合計）は約４１となり、そのうちの第４、第５の膜エレメント１５のろ過水量の累積は約１３．８となる。 As described above, in the multistage device 1 and the circulation device 2, if the element water recovery rate and the element material removal rate are determined, the concentrated water concentration, the filtrate concentration, and the like can be obtained. For example, assuming that the amount of supplied water flowing into the first membrane element 15 of the second bank 12 of the multistage apparatus 1 is 100 and the element water recovery rate is 10%, the second bank 12 The filtered water amounts in the first to fifth membrane elements 15 are 10, 9, about 8, about 7.3, and about 6.5, respectively, and the amount of concentrated water flowing into the subsequent membrane element 15 is 90, 81, about 73, is about 6 5. Therefore, the accumulation (total) of the filtrate amount of the first to fifth membrane elements 15 is about 41, and the accumulation of the filtrate amount of the fourth and fifth membrane elements 15 is about 13.8.

他方、循環型装置２において多段型装置１の第２バンク１２の第４、第５の膜エレメント１５、１５の水量収支を再現する場合には、循環型装置２に流入する（循環水量を含む）供給水量は約７３となる。多段型装置１の第１〜第５の膜エレメント１５の累積ろ過水量は約４１であり、第４、第５の膜エレメント１５、１５（上流側膜エレメント２１、後流側膜エレメント２１）のろ過水量の累計は約１３．８であるので、循環型装置２の系外からの供給水量は（約１３．８／約４１）・１００＝約３３．６となる。したがって、循環水量は約７３−約３３．６＝約３９．４となる。そして、循環型装置２から系外に流出するろ過水量は約３３．６−約１３．８＝約１９．２となる。 On the other hand, when the water amount balance of the fourth and fifth membrane elements 15 and 15 of the second bank 12 of the multistage device 1 is reproduced in the circulation type device 2, it flows into the circulation type device 2 (including the circulation water amount). ) The amount of water supplied is about 73. The accumulated amount of filtered water of the first to fifth membrane elements 15 of the multistage apparatus 1 is about 41, and the fourth and fifth membrane elements 15 and 15 ( upstream membrane element 21 and wake membrane element 21). Since the total amount of filtered water is about 13.8, the amount of water supplied from outside the system of the circulation type apparatus 2 is (about 13.8 / about 41) · 100 = about 33.6. Therefore, the amount of circulating water is about 73−about 33.6 = about 39.4. The amount of filtered water flowing out of the circulation type apparatus 2 is about 33.6 to about 13.8 = about 19.2.

次に、多段型装置１の処理機能を循環型装置２によって実証実験するための全般的な手順を説明する。先ず、多段型装置１の任意の膜エレメント１５における水量収支を上記式１〜７によって算出する。次に、その算出結果に基づいた水量収支を用いて循環型装置２を運転する。次に、多段型装置１の同じ膜エレメント１５における水量収支を再現した循環型装置２の水量収支を実測すると共に、供給水水質、ろ過水水質、および濃縮水水質の物質濃度を実測する。次に、循環型装置２で得た水量および水質の実測値から物質除去率を上記式８〜１９によって算出する。次に、算出した物質除去率を用いて多段型装置１の供給水水質、ろ過水水質、および濃縮水水質の物質濃度を算出する。
次に、多段型装置１の同じ膜エレメント１５における水量収支を実測すると共に、供給水水質、ろ過水水質、および濃縮水水質を実測する。そして、この多段型装置１の物質濃度と上記循環型装置２の物質濃度とがほぼ一致することを確認する。
Next, a general procedure for demonstrating the processing function of the multistage apparatus 1 by the circulation apparatus 2 will be described. First, the water balance in any membrane element 15 of the multistage apparatus 1 is calculated by the above formulas 1-7. Next, the circulation type apparatus 2 is operated using the water amount balance based on the calculation result. Next, the water amount balance of the circulation type device 2 that reproduces the water amount balance in the same membrane element 15 of the multistage device 1 is measured, and the substance concentrations of the quality of the feed water, the filtered water, and the concentrated water are measured. Next, the substance removal rate is calculated by the above formulas 8 to 19 from the actually measured values of the water amount and the water quality obtained by the circulation type device 2. Next, the substance concentration of the feed water quality, filtered water quality, and concentrated water quality of the multistage apparatus 1 is calculated using the calculated substance removal rate.
Next, the water balance in the same membrane element 15 of the multistage apparatus 1 is measured, and the quality of the feed water, the quality of the filtered water, and the quality of the concentrated water are measured . Then, it is confirmed that the substance concentration of the multistage apparatus 1 and the substance concentration of the circulation apparatus 2 are substantially the same.

実施の形態２．
なお、上述の実施の形態１では１基の循環型装置２によって多段型装置１の処理機能を予測したが、多段型装置１の任意の膜エレメント１５における処理機能影響因子を再現できる２基以上の循環型装置２を用意し、この循環装置２に前記処理機能影響因子を再現してそれを運転することによっても、多段型装置１の処理機能を予測できる。この場合には、循環型装置２から物質除去率を算出し、この物質除去率を用いることにより、多段型装置１で得られるであろう濃度を算出する。 Embodiment 2. FIG.
In the first embodiment described above, the processing function of the multistage apparatus 1 is predicted by one circulating apparatus 2, but two or more apparatuses that can reproduce the processing function influencing factors in any membrane element 15 of the multistage apparatus 1 can be reproduced. The processing function of the multistage apparatus 1 can also be predicted by preparing the circulating apparatus 2 and reproducing the processing function influencing factors in the circulating apparatus 2 and operating it. In this case, the substance removal rate is calculated from the circulation type apparatus 2, and the concentration that would be obtained by the multistage apparatus 1 is calculated by using this substance removal rate.

多段型装置１の流量予測式の確認を次のように行なった。ただし、以下の表１にも示すように、多段型装置１はバンクの構成を直列３段とし、ベッセル１６の構成を６−３−１とし、各ベッセル１６には５つの膜エレメント１５を収容した。表１において、３つのバンクは第１（１ｓｔ）バンク、第２（２ｎｄ）バンク、第３（３ｒｄ）バンクと表し、５つの膜エレメント１５は、上流側から順次に１エレメント〜５エレメントと表してある。このような多段型装置１の構成で次の手順を進めた。
（１）各バンクのフラックスとバンク毎のエレメント水回収率とをそれぞれ一定と仮定し、多段型装置１のろ過水量の予測値を上記式３から得た。
（２）多段型装置１を表１に示す条件で運転し、多段型装置１のろ過水量の実測値を得た。
（３）多段型装置１のろ過水量の予測値と実測値の関係は図５に示すようになった。
（４）図５から明らかなように、多段型装置１のろ過水量を実用上問題のない程度に予測することが可能となり、流量予測式の妥当性を確認できた。なお、実際には膜エレメント１５の圧力損失によって膜ろ過圧力が膜エレメント１５毎に変化するので、エレメント水回収率は同一ベッセル１６内であっても異なり、ベッセル１６の上流側で高く、下流側で低くなる。しかし、エレメント水回収率が同一ベッセル１６内で一定であると仮定すれば、多段型装置１のろ過水量を実用上問題のない程度に予測することが可能となる。 The flow rate prediction formula of the multi-stage apparatus 1 was confirmed as follows. However, as shown in Table 1 below, the multi-stage apparatus 1 has a bank configuration of three stages in series, a vessel 16 of 6-3-1, and each vessel 16 accommodates five membrane elements 15. did. In Table 1, the three banks are represented as a first (1st) bank, a second (2nd) bank, and a third (3rd) bank, and the five membrane elements 15 are represented as 1 to 5 elements sequentially from the upstream side. It is. The following procedure was advanced with such a configuration of the multistage apparatus 1.
(1) Assuming that the flux of each bank and the element water recovery rate for each bank are constant, the predicted value of the filtered water amount of the multi-stage apparatus 1 was obtained from Equation 3 above.
(2) The multi-stage apparatus 1 was operated under the conditions shown in Table 1, and an actual measured value of the filtrate amount of the multi-stage apparatus 1 was obtained.
(3) The relationship between the predicted value of the filtered water amount of the multi-stage apparatus 1 and the actual measurement value is as shown in FIG.
(4) As is clear from FIG. 5, the amount of filtered water of the multistage apparatus 1 can be predicted to a practically satisfactory level, and the validity of the flow rate prediction formula can be confirmed. Actually, since the membrane filtration pressure changes for each membrane element 15 due to the pressure loss of the membrane element 15, the element water recovery rate is different even in the same vessel 16, and is higher on the upstream side of the vessel 16, and on the downstream side. At low. However, if it is assumed that the element water recovery rate is constant in the same vessel 16, it is possible to predict the amount of filtered water of the multistage apparatus 1 to a practically satisfactory level.

多段型装置１および循環型装置２の濃度予測式の確認を次のように行なった。
（１）以下の表２に示す条件（フラックスおよびエレメント水回収率を一定）の下で多段型装置１の濃度の予測値を上記式６および式７から算出した。
（２）表２に示す条件（図１に４つの楕円で示す箇所の水量収支の再現、すなわち第１バンク１１の第１、第２の膜エレメント１５の水量収支または第２〜第４バンク１２〜１４のそれぞれの第３、第４の膜エレメント１５の水量収支の再現）の下で循環型装置２の物質濃度（供給水濃度、濃縮水濃度、およびろ過水濃度）の予測値を上記式１７〜式１９から得た。
（３）多段型装置１と循環型装置２を表２に示す条件で運転した。
（４）例として有機物質の一指標であるＴＯＣ（全有機性炭素）濃度の実測値を得た。
（５）濃度予測式による多段型装置１のＴＯＣ濃度の予測値と実測値の関係は図６に示すようになり、濃度予測式による循環型装置２のＴＯＣ濃度の予測値と実測値の関係は図７に示すようになった。
（６）図６および図７から明らかなように、多段型装置１と循環型装置２の双方において濃度の予測値と実測値に優れた一致が見られ、濃度予測式の妥当性を確認できた。なお、多段型装置１の濃度の実測値と循環型装置２の濃度の実測値とを比較すると、高濃縮域になるにつれて前者が後者よりも大きかった。 The concentration prediction formulas of the multistage apparatus 1 and the circulation type apparatus 2 were confirmed as follows.
(1) The predicted value of the concentration of the multistage apparatus 1 was calculated from the above formulas 6 and 7 under the conditions shown in Table 2 below (fixed flux and element water recovery rates).
(2) Conditions shown in Table 2 (reproduction of the water balance at the locations indicated by four ellipses in FIG. 1, ie, the water balance of the first and second membrane elements 15 of the first bank 11 or the second to fourth banks 12 ˜14 (reproduction of water amount balance of each of the third and fourth membrane elements 15), the predicted values of the substance concentration (feed water concentration, concentrated water concentration, and filtrate concentration) of the circulating apparatus 2 are expressed by the above formula. Obtained from 17-19.
(3) The multistage device 1 and the circulation device 2 were operated under the conditions shown in Table 2.
(4) As an example, an actual measurement value of TOC (total organic carbon) concentration, which is an index of organic substances, was obtained.
(5) The relationship between the predicted value of the TOC concentration of the multistage apparatus 1 based on the concentration prediction formula and the actual measurement value is as shown in FIG. 6, and the relationship between the predicted value of the TOC concentration of the circulating apparatus 2 based on the concentration prediction formula and the actual measurement value. As shown in FIG.
(6) As is clear from FIGS. 6 and 7, both the multistage apparatus 1 and the circulation apparatus 2 have excellent agreement between the predicted value of the concentration and the actual measurement value, and the validity of the concentration prediction formula can be confirmed. It was. In addition, when the measured value of the density | concentration of the multistage type apparatus 1 and the measured value of the density | concentration of the circulation type apparatus 2 were compared, the former was larger than the latter as it became a high concentration area | region.

多段型装置１の流量予測式と濃度予測式では、膜エレメント１５毎の水回収率と物質除去率が求まれば、多段型装置１の全体の水量分布と濃度分布を算出することができる。一過型多段ナノろ過実施設を設計する際には、エレメント水回収率は初期条件（ろ過水量とシステム水回収率＝供給水量）によって算出できるので、膜エレメント１５毎のエレメント物質除去率を与えることができれば、一過型多段ナノろ過実施設の濃度分布の予測が可能となる。ここでは、循環型装置２で得た水回収率と物質除去率の関係を多段型装置１の濃度予測式に適用することにより、循環型装置２による多段型装置１の水質予測を行ない、得られた水質の予測値と多段型装置１の水質の実測値から循環型装置２による多段型装置１の水質予測を次の手順で行なった。
（１）多段型装置１は、図１に示す構成とし、そのフラックス（流束）を各バンク当たり０．６ｍ／ｄとし、回収率を９５％として運転した。循環型装置２は、多段型装置１の第１バンク１１の第１、第２エレメント１５または第２〜第４バンク１２〜１４の第４、第５エレメント１５の水量収支を再現して運転した。
（２）循環型装置２で得た水回収率と物質除去率の関係を上記式６および式７に適用して多段型装置１の濃度の予測値を算出した。
（３）多段型装置１の濃度の実測値を得た。
（４）多段型装置１と循環型装置２のシステム水回収率と物質除去率の関係について、ＴＯＣでの比較結果は図８のようになった。
（５）循環型装置２による多段型装置１の濃度の予測値と実測値の関係について、ＴＯＣでの比較結果は図９のようになった。ただし、縦軸は供給水濃度に対するろ過水濃度および濃縮水濃度の比としてある。
（６）循環型装置２による多段型装置１の濃度の予測値と実測値の関係について、多段型装置１のバンク１１〜１４の各々および全体のＴＯＣでのろ過水水質の比較結果は図１０のようになった。ただし、縦軸は供給水濃度に対するろ過水濃度の比としてある。
（７）図８から明らかなように、多段型装置１と循環型装置２の双方において、システム水回収率に対する物質除去率の変化が同程度となった。したがって、図９および図１０から明らかなように、システム水回収率に対する供給水濃度を１とした場合に、ろ過水の濃度比と濃縮水の濃度比も予測値と実測値でほぼ等しくなった。これにより、多段型装置１の水質予測が実用上極めて有効であることが分かった。 If the water recovery rate and the substance removal rate for each membrane element 15 are obtained in the flow rate prediction formula and the concentration prediction formula of the multistage apparatus 1, the entire water amount distribution and concentration distribution of the multistage apparatus 1 can be calculated. When designing a single-stage multi-stage nanofiltration facility, the element water recovery rate can be calculated based on the initial conditions (filtered water amount and system water recovery rate = feed water amount), thus giving an element material removal rate for each membrane element 15 If possible, it is possible to predict the concentration distribution of the transient multi-stage nanofiltration facility. Here, the water quality prediction of the multistage apparatus 1 by the circulation type apparatus 2 is performed by applying the relationship between the water recovery rate and the substance removal rate obtained by the circulation type apparatus 2 to the concentration prediction formula of the multistage apparatus 1. The water quality prediction of the multistage apparatus 1 by the circulation apparatus 2 was performed from the estimated value of the water quality and the actually measured value of the water quality of the multistage apparatus 1 according to the following procedure.
(1) The multistage apparatus 1 has the configuration shown in FIG. 1 and was operated with a flux (flux) of 0.6 m / d for each bank and a recovery rate of 95%. The circulation type apparatus 2 was operated by reproducing the water amount balance of the first and second elements 15 of the first bank 11 of the multistage apparatus 1 or the fourth and fifth elements 15 of the second to fourth banks 12 to 14. .
(2) The predicted value of the concentration of the multi-stage apparatus 1 was calculated by applying the relationship between the water recovery rate and the substance removal rate obtained in the circulation type apparatus 2 to the above formulas 6 and 7.
(3) The measured value of the concentration of the multistage apparatus 1 was obtained.
(4) Regarding the relationship between the system water recovery rate and the material removal rate of the multi-stage type device 1 and the circulation type device 2, the comparison result in the TOC is as shown in FIG.
(5) As for the relationship between the predicted value of the concentration of the multi-stage apparatus 1 by the circulation apparatus 2 and the actual measurement value, the comparison result in the TOC is as shown in FIG. However, the vertical axis represents the ratio of the filtrate concentration and the concentrated water concentration to the supply water concentration.
(6) Regarding the relationship between the predicted value of the concentration of the multistage apparatus 1 by the circulation apparatus 2 and the actually measured value, the comparison results of the filtered water quality in each of the banks 11 to 14 of the multistage apparatus 1 and the entire TOC are shown in FIG. It became like this. However, the vertical axis represents the ratio of the filtrate concentration to the supply water concentration.
(7) As is apparent from FIG. 8, the change in the material removal rate with respect to the system water recovery rate is about the same in both the multistage device 1 and the circulation device 2. Therefore, as apparent from FIGS. 9 and 10, when the supply water concentration with respect to the system water recovery rate is 1, the concentration ratio of the filtrate and the concentration ratio of the concentrated water are substantially equal between the predicted value and the actual measurement value. . Thereby, it turned out that the water quality prediction of the multistage apparatus 1 is very effective practically.

以上のように、多段型装置１の流量予測式と濃度予測式から算出した流量と濃度の予測値が実測値とほぼ一致し、かつ循環型装置２の濃度予測式から算出した濃度の予測値と実測値もほぼ一致し、各予測式の妥当性を確認した。また、循環型装置２で得た水回収率と物質除去率の関係を用いて算出した多段型装置１のろ過水と濃縮水の濃度の予測値と実測値はほぼ一致し、循環型装置２による多段型装置１の濃度予測が可能であることを明らかにした。 As described above, the predicted value of the flow rate and the concentration calculated from the flow rate prediction formula and the concentration prediction formula of the multistage device 1 substantially match the actual measurement value, and the predicted value of the concentration calculated from the concentration prediction formula of the circulation type device 2 The measured values almost coincided with each other, and the validity of each prediction formula was confirmed. In addition, the predicted value and the measured value of the concentration of filtrate and concentrated water of the multi-stage apparatus 1 calculated using the relationship between the water recovery rate and the substance removal rate obtained by the circulation apparatus 2 are almost the same, and the circulation apparatus 2 It was clarified that the concentration prediction of the multi-stage apparatus 1 can be performed.

したがって、多段型装置１の機能評価が必要な場合には、多段型装置１の任意の箇所の少なくとも１つの膜エレメント１５の周りの処理機能影響因子を循環型装置２で再現して物質除去率を求めることにより、多段型装置１の物質濃度を理論的に算出できる。この多段型装置１は一過型多段ナノろ過実施設に他ならないので、一過型多段ナノろ過実施設の研究開発にあたっては一過型多段ナノろ過実施設を必要とせず、循環型装置２のみによって一過型多段ナノろ過実施設の処理機能を予測できる。よって、一過型多段ナノろ過実施設の研究開発コスト、設備コスト、運転管理コストなどを大幅に削減できる。 Therefore, when it is necessary to evaluate the function of the multistage apparatus 1, the circulation function apparatus 2 reproduces the processing function influencing factors around the at least one membrane element 15 at an arbitrary position of the multistage apparatus 1. , The substance concentration of the multistage apparatus 1 can be calculated theoretically. Since this multi-stage apparatus 1 is nothing but a single-stage multi-stage nanofiltration facility, the R & D of the single-stage multi-stage nano-filtration apparatus does not require a single-stage multi-stage nano-filtration apparatus, and only the circulation-type apparatus 2 Can predict the processing function of the temporary multi-stage nanofiltration facility. Therefore, the R & D cost, facility cost, operation management cost, etc. of the temporary multistage nanofiltration facility can be greatly reduced.

この発明の実施の形態１における多段型装置の構成図である。It is a block diagram of the multistage apparatus in Embodiment 1 of this invention. この発明の実施の形態１における循環型装置の構成図である。It is a block diagram of the circulation type apparatus in Embodiment 1 of this invention. 多段型装置のエレメント周りの収支を説明する図である。It is a figure explaining the balance around the element of a multistage type apparatus. 循環型装置のエレメント周りの収支を説明する図である。It is a figure explaining the balance around the element of a circulation type device. ろ過水量の予測値と実測値の関係を示すグラフ図である。It is a graph which shows the relationship between the predicted value of the amount of filtrate water, and an actual value. 濃度予測式による多段型装置のＴＯＣ濃度の予測値と実測値の関係を示すグラフ図である。It is a graph which shows the relationship between the predicted value of TOC density | concentration of a multistage type | mold apparatus by a density | concentration prediction formula, and an actual value. 濃度予測式による循環型装置のＴＯＣ濃度の予測値と実測値の関係を示すグラフ図である。It is a graph which shows the relationship between the predicted value and actual value of the TOC density | concentration of a circulation type apparatus by a density | concentration prediction type | formula. システム水回収率とＴＯＣ除去率の関係を示すグラフ図である。It is a graph which shows the relationship between a system water collection | recovery rate and a TOC removal rate. 循環型装置による多段型装置のＴＯＣ濃度の予測値と実測値の関係を示すグラフ図である。It is a graph which shows the relationship between the predicted value of TOC density | concentration of a multistage type apparatus by a circulation type apparatus, and an actual value. 循環型装置による多段型装置のＴＯＣ濃度の予測値と実測値の関係を示すグラフ図である。It is a graph which shows the relationship between the predicted value of TOC density | concentration of a multistage type apparatus by a circulation type apparatus, and an actual value.

Explanation of symbols

１５膜エレメント
１７膜モジュール
２１上流側膜エレメント、後流側膜エレメント
１６ベッセル
２２上流側ベッセル、後流側ベッセル
２４供給水槽
２５供給水管
２６供給ポンプ
２７上流側ろ過水管、後流側ろ過水管
２８ろ過水槽
２９上流側濃縮水管
３０後流側濃縮水管

15 Membrane element
17 Membrane module
21 Upstream membrane element, wake membrane element 16 Vessel
22 upstream vessel, downstream vessel
24 Supply water tank 25 Supply water pipe
26 Supply pump 27 upstream-side filtered water pipe , wake-side filtered water pipe
28 Filtration tank
29 Upstream concentrated water pipe
30 Concentrated water pipe on the downstream side

Claims

In the circulation type nanofiltration test device that predicts the treatment function of the transient multistage nanofiltration implementation that nanofilters the pretreated feed water,
A feed water tank for storing the feed water, an upstream membrane element for nano-filtering the feed water, a feed water pipe for feeding the feed water from the feed water tank to the upstream membrane element, a feed pump provided in the feed water pipe, A downstream membrane element that nano-filters the concentrated water of the upstream membrane element, an upstream concentrated water pipe that guides the concentrated water of the upstream membrane element to the downstream membrane element, and a concentration generated in the downstream membrane element A downstream-side concentrated water pipe for discharging water out of the system, a filtration water tank for storing the filtered water of the upstream-side membrane element and the downstream-side membrane element, and an upstream-side filtration for guiding the filtered water of the upstream-side membrane element to the filtered water tank A water pipe, a wake-side filtered water pipe that guides the filtered water of the wake-side membrane element to the filtration water tank, and a part of the concentrated water of the wake-side membrane element are circulated upstream from the supply pump of the supply water pipe. Recycling nanofiltration test apparatus characterized by comprising a circulating water pipe for.

Using the circulating nanofiltration test apparatus according to claim 1, the relationship between the supply water concentration, the water recovery rate, and the substance removal rate is applied to the concentration prediction formula of the one-step multistage nanofiltration facility. In the circulation type nanofiltration test method for predicting the processing function of the one-stage multistage nanofiltration facility,
The feed water concentration C _fn, the water recovery rate r _n, the material removal rate in case of the R _n, the prediction type of concentrated water concentration C _bn in n-th of the membrane element of the transient multistage nanofiltration real property ,
C _bn = C _fn · {r _n (1-r _n ) -2} / {r _n (1 + R _n ) -2}
And the prediction formula of the filtrate concentration C _pn is C _pn = C _fn · (r _n −2) (1−R _n ) / {r _n (1 + R _n ) −2}
A circulating nanofiltration test method characterized by the following.