JP5582847B2 - Purified water production equipment - Google Patents

Purified water production equipment Download PDF

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JP5582847B2
JP5582847B2 JP2010085331A JP2010085331A JP5582847B2 JP 5582847 B2 JP5582847 B2 JP 5582847B2 JP 2010085331 A JP2010085331 A JP 2010085331A JP 2010085331 A JP2010085331 A JP 2010085331A JP 5582847 B2 JP5582847 B2 JP 5582847B2
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membrane
purified water
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JP2011212628A (en
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雄之 寺田
仁一 佐藤
博 藤原
真夫 森本
喜幸 寺尾
洋一 鴨下
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Nipro Corp
Mitsubishi Chemical Cleansui Corp
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Mitsubishi Chemical Cleansui Corp
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本発明は、精製水製造装置に関する。   The present invention relates to a purified water production apparatus.

人工透析で使用される透析液などには、カルシウム、マグネシウムなどの２価の陽イオン、残留塩素、細菌類、不純物などが除かれた高純度の精製水が用いられている。このような高純度の精製水は、例えば、水道水などの原水をイオン交換樹脂や活性炭により前処理して前記陽イオンや残留塩素を除き、逆浸透膜（以下、「ＲＯ膜」という。）で濾過して細菌類、不純物など除去することにより製造される。精製水の製造には、特にＲＯ膜を用いる精製水製造装置が広く用いられている。   As the dialysate used in artificial dialysis, high-purity purified water from which divalent cations such as calcium and magnesium, residual chlorine, bacteria and impurities are removed is used. Such high-purity purified water is prepared by, for example, pre-treating raw water such as tap water with an ion exchange resin or activated carbon to remove the cation and residual chlorine, and reverse osmosis membrane (hereinafter referred to as “RO membrane”). It is manufactured by removing the bacteria and impurities by filtration with a filter. In the production of purified water, a purified water production apparatus using an RO membrane is widely used.

精製水製造装置としては、例えば、以下に示すものが挙げられる。
（ｉ）活性炭塔とＲＯ膜を有する精製水製造装置（特許文献１）。
（ii）２つのＲＯ膜を直列配置して原水を２度濾過する精製水製造装置（特許文献２）。
しかし、精製水製造装置（ｉ）のような、ＲＯ膜を利用した従来の精製水製造装置では、精製水の回収率、すなわち原水量に対して得られる精製水量の割合が、約６０〜７０％と低く、原水の３０〜４０％が濃縮水として排水されている。また、精製水製造装置（ii）のような２つのＲＯ膜で濾過する装置についても、得られる精製水の水質は向上するものの、それぞれのＲＯ膜から濃縮水が排水されるため、精製水の回収率が５０〜７０％と低く、原水の約３０〜５０％が濃縮水として排水される。また、特に原水の水質が悪い場合には、精製水の回収率が４０〜５０％に低下することもある。このように、精製水の回収率が低いと、水道費用が増大するため、ランニングコストが高くなる。 As a purified water manufacturing apparatus, what is shown below is mentioned, for example.
(I) A purified water production apparatus having an activated carbon tower and an RO membrane (Patent Document 1).
(Ii) A purified water production apparatus in which two RO membranes are arranged in series to filter raw water twice (Patent Document 2).
However, in the conventional purified water production apparatus using the RO membrane, such as the purified water production apparatus (i), the recovery rate of the purified water, that is, the ratio of the purified water amount to the raw water amount is about 60 to 70. %, 30-40% of raw water is drained as concentrated water. Moreover, although the quality of the purified water obtained also improves about the apparatus filtered with two RO membranes like the purified water production apparatus (ii), since concentrated water is drained from each RO membrane, purified water The recovery rate is as low as 50 to 70%, and about 30 to 50% of the raw water is drained as concentrated water. Moreover, especially when the quality of raw water is poor, the recovery rate of purified water may be reduced to 40 to 50%. As described above, when the recovery rate of purified water is low, the running cost increases because the cost of water supply increases.

一方、精製水の回収率を向上させる精製水製造装置としては、例えば、以下に示す精製水製造装置（iii）が示されている。
（iii）原水を濾過する第１のＲＯ膜と、第１のＲＯ膜を透過しなかった濃縮水を濾過する第２のＲＯ膜とを有する精製水製造装置（特許文献３）。
精製水製造装置（iii）では、第１のＲＯ膜を透過しなかった濃縮水をさらに濾過して精製水を得るため、精製水の回収率が向上する。しかし、第２のＲＯ膜は不純物が濃縮された濃縮水を濾過するため、負担が大きい。そのため、第２のＲＯ膜の寿命（ＲＯ膜の寿命は通常３〜４年）が短くなるうえ、得られる精製水の水質も低下する。
また、ＲＯ膜を有する装置であって、該ＲＯ膜を透過しなかった濃縮水を返送し、原水と混合させて再利用する精製水製造装置も知られている。しかし、該精製水製造装置においても、濃縮水を混合することで原水中の不純物の濃度が約１．５〜２倍になり、ＲＯ膜にかかる負担が増大する。そのため、得られる精製水の水質の低下、ＲＯ膜の寿命の短縮の問題がある。 On the other hand, as a purified water production apparatus that improves the recovery rate of purified water, for example, a purified water production apparatus (iii) shown below is shown.
(Iii) A purified water production apparatus having a first RO membrane that filters raw water and a second RO membrane that filters concentrated water that has not permeated through the first RO membrane (Patent Document 3).
In the purified water production apparatus (iii), since the concentrated water that has not permeated through the first RO membrane is further filtered to obtain purified water, the recovery rate of purified water is improved. However, since the second RO membrane filters concentrated water in which impurities are concentrated, the load is large. Therefore, the lifetime of the second RO membrane (the lifetime of the RO membrane is usually 3 to 4 years) is shortened, and the quality of the purified water obtained is also lowered.
There is also known an apparatus for producing purified water that has an RO membrane and returns the concentrated water that has not permeated through the RO membrane, mixed with the raw water, and reused. However, even in the purified water production apparatus, the concentration of impurities in the raw water becomes about 1.5 to 2 times by mixing concentrated water, and the burden on the RO membrane increases. Therefore, there is a problem that the quality of the purified water obtained is lowered and the life of the RO membrane is shortened.

特開２００３−２６０４６３号公報JP 2003-260463 A 特開２００８−２３７９７１号公報JP 2008-237971 A 特開平１１−４７５６６号公報Japanese Patent Laid-Open No. 11-47566

本発明は、精製水の回収率が高く、ＲＯ膜の寿命が短くなることを抑制することができ、優れた水質の精製水を低コストで製造できる精製水製造装置の提供を目的とする。   An object of the present invention is to provide a purified water production apparatus that has a high recovery rate of purified water, can suppress the life of the RO membrane from being shortened, and can produce purified water having excellent water quality at a low cost.

本発明は、前記課題を解決するために以下の構成を採用した。
［１］原水をイオン交換樹脂によって軟水化する第１軟水化手段と、前記第１軟水化手段により軟水化された原水を活性炭で濾過して残留塩素を除去する塩素除去手段と、残留塩素が除去された原水を下記ナノ濾過膜で濾過して軟水化する第２軟水化手段と、前記第２軟水化手段により軟水化された原水をＲＯ膜で濾過して精製水を得る精製手段と、前記ＲＯ膜を透過しなかった濃縮水を、前記第２軟水化手段の一次側の原水と混合する濃縮水返送ラインと、を有していることを特徴とする精製水製造装置。
（ナノ濾過膜）
濃度２０００ｍｇ／ＬのＮａＣｌ水溶液を、運転圧力０．５ＭＰａ、温度２５℃、ｐＨ６．５〜７．０、膜透過水の回収率１５％の条件で３０分間濾過したときのＮａＣｌの除去率が７５〜９５％であるナノ濾過膜。
［２］前記ナノ濾過膜が、濃度２０００ｍｇ／ＬのＭｇＳＯ４水溶液を、運転圧力０．５ＭＰａ、温度２５℃、ｐＨ６．５〜７．０、膜透過水の回収率１５％の条件で３０分間濾過したときのＭｇＳＯ４の除去率が９９．５％以上のナノ濾過膜である、前記［１］に記載の精製水製造装置。
［３］前記濃縮水返送ラインにより前記濃縮水の９０％以上が原水と混合される、前記［１］または［２］に記載の精製水製造装置。 The present invention employs the following configuration in order to solve the above problems.
[1] A first water softening means for softening raw water with an ion exchange resin, a chlorine removing means for removing the residual chlorine by filtering the raw water softened by the first water softening means with activated carbon, A second water softening means for softening the filtered raw water with the following nanofiltration membrane; a purification means for obtaining purified water by filtering the raw water softened by the second water softening means with an RO membrane; An apparatus for producing purified water, comprising: a concentrated water return line for mixing concentrated water that has not permeated the RO membrane with raw water on a primary side of the second water softening means.
(Nanofiltration membrane)
When the NaCl aqueous solution having a concentration of 2000 mg / L is filtered for 30 minutes under the conditions of an operating pressure of 0.5 MPa, a temperature of 25 ° C., a pH of 6.5 to 7.0, and a recovery rate of membrane permeated water of 15%, the NaCl removal rate is 75. Nanofiltration membrane that is ~ 95%.
[2] The nanofiltration membrane is an aqueous MgSO 4 solution having a concentration of 2000 mg / L, 30 minutes under the conditions of an operating pressure of 0.5 MPa, a temperature of 25 ° C., a pH of 6.5 to 7.0, and a recovery rate of membrane permeated water of 15%. The apparatus for producing purified water according to [1] above, which is a nanofiltration membrane having a removal rate of MgSO 4 of 99.5% or more when filtered.
[3] The purified water production apparatus according to [1] or [2], wherein 90% or more of the concentrated water is mixed with raw water by the concentrated water return line.

本発明の精製水製造装置は、精製水の回収率が高く、ＲＯ膜の寿命が短くなることを抑制することができ、低コストで、優れた水質の精製水を製造できる。   The purified water production apparatus of the present invention has a high purified water recovery rate, can suppress the life of the RO membrane from being shortened, and can produce purified water with excellent water quality at low cost.

本発明の精製水製造装置の実施形態の一例を示した概略図である。It is the schematic which showed an example of embodiment of the purified water manufacturing apparatus of this invention.

以下、本発明の精製水製造装置の実施形態の一例を図１に基づいて詳細に説明する。
本実施形態の精製水製造装置１は、図１に示すように、原水を貯留する原水タンク１１と、原水タンク１１から送られてくる原水をイオン交換樹脂によって軟水化する第１軟水化手段１２と、第１軟水化手段１２により軟水化された原水を活性炭で濾過して残留塩素を除去する塩素除去手段１３と、原水の水質をチェックするチェックフィルタ１４と、残留塩素が除去された原水を後述するナノ濾過膜（以下、「ＮＦ膜」という。）で濾過して軟水化する第２軟水化手段１５と、第２軟水化手段１５により軟水化された原水（以下、「ＮＦ水」という。）をＲＯ膜で濾過して精製水を得る精製手段１６と、精製水を貯留する精製水タンク１７とを有している。 Hereinafter, an example of an embodiment of the purified water production apparatus of the present invention will be described in detail with reference to FIG.
As shown in FIG. 1, the purified water production apparatus 1 according to the present embodiment includes a raw water tank 11 that stores raw water, and first water softening means 12 that softens raw water sent from the raw water tank 11 with an ion exchange resin. A chlorine removing means 13 for removing the residual chlorine by filtering the raw water softened by the first water softening means 12 with activated carbon, a check filter 14 for checking the quality of the raw water, and the raw water from which the residual chlorine has been removed. A second water softening means 15 that is softened by filtration through a nanofiltration membrane (hereinafter referred to as “NF membrane”), and raw water softened by the second water softening means 15 (hereinafter referred to as “NF water”). .) Is purified by an RO membrane to obtain purified water 16 and a purified water tank 17 for storing purified water.

また、精製水製造装置１は、一端が原水タンク１１に接続され、途中に原水を送水する送水ポン４１が設けられ、他端が第１軟水化手段１２に接続された送水ライン５１と；一端が第１軟水化手段１２に接続され、他端が塩素除去手段１３に接続された送水ライン５２と；一端が塩素除去手段１３に接続され、他端がチェックフィルタ１４に接続された送水ライン５３と；一端がチェックフィルタ１４に接続され、途中に残留塩素が除去された原水を送水する送水ポンプ４２が設けられ、他端が第２軟水化手段１５に接続された送水ライン５４と；一端が第２軟水化手段１５に接続され、途中に上流側から逆止弁２０、電動弁２１、及びＮＦ水を送水する送水ポンプ４３が設けられ、他端が精製手段１６に接続された送水ライン５５と；一端が精製手段１６に接続され、途中に上流側から逆止弁２２及び電動弁２３が設けられ、他端が精製水タンク１７に接続された送水ライン５６と；一端が精製水タンク１７に接続され、途中に上流側から精製水を送水する送水ポンプ４４、及び流量調整弁２４が設けられ、他端が精製水タンク１７に接続された精製水循環ライン５７とを有している。   The purified water production apparatus 1 has a water supply line 51 having one end connected to the raw water tank 11, a water supply pump 41 for supplying raw water in the middle, and the other end connected to the first water softening means 12; Is connected to the first water softening means 12 and the other end is connected to the chlorine removing means 13; and the other end is connected to the chlorine removing means 13 and the other end is connected to the check filter 14. A water supply line 42 having one end connected to the check filter 14 and supplying raw water from which residual chlorine has been removed in the middle, and the other end connected to the second water softening means 15; A water supply line 55 connected to the second water softening means 15, provided with a check valve 20, a motor operated valve 21, and a water supply pump 43 for supplying NF water from the upstream side and having the other end connected to the purification means 16. And one end A water supply line 56 connected to the purifying means 16 and provided with a check valve 22 and an electric valve 23 from the upstream side in the middle, and the other end connected to the purified water tank 17; one end connected to the purified water tank 17; A water supply pump 44 for supplying purified water from the upstream side and a flow rate adjusting valve 24 are provided in the middle, and a purified water circulation line 57 connected to the purified water tank 17 at the other end.

また、精製水製造装置１は、一端が第２軟水化手段１５に接続され、途中に逆止弁２５が設けられ、他端が送水ライン５４における送水ポンプ４２の上流側に合流接続された濃縮水返送ライン５８と；一端が精製手段１６に接続され、途中に上流側から電動弁２６、流量調整弁２７及び逆止弁２８が設けられ、他端が原水タンク１１に接続された濃縮水返送ライン５９と；一端が濃縮水返送ライン５９における電動弁２６の上流側から分岐し、途中に逆止弁２９が設けられ、他端が送水ライン５５における電動弁２１と送水ポンプ４３の間に合流接続された濃縮水返送ライン６０と；一端が送水ライン５５から分岐し、途中に逆止弁３０が設けられ、他端が濃縮水返送ライン５９の逆止弁２８の下流側に合流接続されたＮＦ水返送ライン６１と；一端が精製水タンク１７に接続され、途中に上流側から精製水を送水する送水ポンプ４５、逆止弁３１、及び電動弁３２が設けられ、他端が濃縮水返送ライン６０における逆止弁２９の下流側に合流接続された精製水返送ライン６２と；一端が精製水返送ライン６２における電動弁３２から分岐し、途中に上流側から電動弁３３及び逆止弁３４が設けられ、他端が濃縮水返送ライン５８における逆止弁２５の下流側に合流接続された精製水返送ライン６３と；一端が精製水返送ライン６３における電動弁３３から分岐し、途中に逆止弁３５が設けられ、他端が送水ライン５８における送水ポンプ４１の下流側に合流接続された精製水返送ライン６４と；一端が送水ライン５６における電動弁２３から分岐し、他端が濃縮水返送ライン５９における逆止弁２８の下流側に合流接続された精製水返送ライン６５と；一端が精製水循環ライン５７から分岐し、精製水を末端機器に送水する精製水送水ライン６６とを有する。   Further, the purified water production apparatus 1 has one end connected to the second water softening means 15, a check valve 25 provided in the middle, and the other end joined and connected to the upstream side of the water pump 42 in the water supply line 54. A water return line 58; one end connected to the purifying means 16, a motorized valve 26, a flow rate adjusting valve 27, and a check valve 28 provided on the way from the upstream, and the other end connected to the raw water tank 11 One end branches from the upstream side of the motor-operated valve 26 in the concentrated water return line 59, the check valve 29 is provided in the middle, and the other end joins between the motor-operated valve 21 and the water pump 43 in the water-feed line 55. Connected to the concentrated water return line 60; one end branched from the water feed line 55, a check valve 30 was provided in the middle, and the other end was joined to the downstream side of the check valve 28 of the concentrated water return line 59. NF water return line 61 One end is connected to the purified water tank 17, a water pump 45 for feeding purified water from the upstream side, a check valve 31, and an electric valve 32 are provided, and the other end is a check valve in the concentrated water return line 60. 29, a purified water return line 62 joined and connected to the downstream side of 29; one end branches from the motor-operated valve 32 in the purified water return line 62, and a motor-operated valve 33 and a check valve 34 are provided from the upstream side along the other end. Has a purified water return line 63 joined and connected downstream of the check valve 25 in the concentrated water return line 58; one end branches from the electric valve 33 in the purified water return line 63, and a check valve 35 is provided in the middle. The purified water return line 64 is joined at the other end to the downstream side of the water pump 41 in the water feed line 58; one end branches from the electric valve 23 in the water feed line 56, and the other end is the concentrated water return line 59. Purified water return line 65 which is merged connected downstream of the definitive check valve 28; one end is branched from the purified water circulation line 57, and a purified water supply line 66 for water supply purified water to the end device.

また、精製水製造装置１は、一端が濃縮水返送ライン５８における逆止弁２５の上流側から分岐し、途中に上流側から電動弁３６及び流量調整弁３７が設けられた、第２軟水化手段１５から排出される濃縮水を排水する排水ライン６７と；一端が送水ライン５５における逆止弁２０と電動弁２１の間から分岐し、途中に電動弁３８が設けられた、ＮＦ水を排水する排水ライン６８と；一端が濃縮水返送ライン６０における逆止弁２９の上流側から分岐し、途中に弁３９が設けられた、精製手段１６から排出される濃縮水を排水する排水ライン６９と；一端が精製水返送ライン６２における送水ポンプ４５と逆止弁３１の間から分岐し、途中に弁４０が設けられた、精製水を排水する排水ライン７０と；を有している。   Further, the purified water production apparatus 1 has a second water softening in which one end branches from the upstream side of the check valve 25 in the concentrated water return line 58 and the motorized valve 36 and the flow rate adjustment valve 37 are provided from the upstream side in the middle. Drainage line 67 for draining the concentrated water discharged from the means 15; one end branching from between the check valve 20 and the motor-operated valve 21 in the water supply line 55, and draining the NF water provided with the motor-operated valve 38 in the middle A drain line 68 that drains the concentrated water discharged from the purification means 16 and having one end branched from the upstream side of the check valve 29 in the concentrated water return line 60 and provided with a valve 39 in the middle. A drainage line 70 for draining purified water, one end of which is branched from between the water supply pump 45 and the check valve 31 in the purified water return line 62 and provided with a valve 40 in the middle.

原水タンク１１の材質としては、精製水製造装置の原水タンクに通常用いられる材質であればよく、例えば、塩化ビニル、ステンレスなどが挙げられる。
原水タンク１１は、原水タンク１１内の液面レベルを感知する図示しない液面感知手段が設けられており、原水量を調節できるようになっている。液面感知手段としては、例えば、レベルスイッチ、フロートセンサー、ボールタップなどが挙げられる。
また、原水タンク１１には、原水の温度を所定の温度に調節する、図示しない加温ユニットが設けられている。加温ユニットとしては、例えば、電気ヒータや、給湯、蒸気などによる加温手段などが挙げられる。 The material of the raw water tank 11 may be any material that is usually used for a raw water tank of a purified water production apparatus, and examples thereof include vinyl chloride and stainless steel.
The raw water tank 11 is provided with liquid level sensing means (not shown) for sensing the liquid level in the raw water tank 11 so that the amount of raw water can be adjusted. Examples of the liquid level sensing means include a level switch, a float sensor, and a ball tap.
The raw water tank 11 is provided with a heating unit (not shown) that adjusts the temperature of the raw water to a predetermined temperature. Examples of the heating unit include an electric heater, hot water supply, heating means using steam, and the like.

第１軟水化手段１２は、イオン交換樹脂によって、原水に含まれているＣａ２＋、Ｍｇ２＋などを樹脂に吸着し、代わりにＮａ＋を放出することで軟水化するものであり、イオン交換樹脂を備えた公知の軟水器を用いることができる。軟水器は、樹脂の吸着能力が低下した際、該樹脂に塩水を接触させることで再生できる。
第１軟水化手段１２は、Ｍｇ２＋、Ｃａ２＋などの硬度成分を除去することで、第２軟水化手段１５にかかる負担（目詰まりなど）を軽減させ、その寿命をより長くする働きもある。 The first water softening means 12 is an ion exchange resin that softens water by adsorbing Ca 2+ , Mg 2+ and the like contained in the raw water to the resin, and releasing Na + instead. A known water softener equipped with can be used. The water softener can be regenerated by bringing salt water into contact with the resin when the resin adsorption capacity decreases.
The 1st water softening means 12 removes hardness components, such as Mg <2+> , Ca < 2+> , reduces the burden (clogging etc.) concerning the 2nd water softening means 15, and also has a function which makes the lifetime longer. .

塩素除去手段１３は、第１軟水化手段１２によって軟水化された原水を活性炭で濾過して残留塩素を除去する手段である。具体的には、活性炭フィルタ、活性炭が充填された活性炭濾過器などが挙げられる。
チェックフィルタ１４は、原水の水質をチェックするフィルタであり、活性炭の微粉及び原水中の細かい浮遊物などを除去する役割を果たす。チェックフィルタ１４は、精製水製造装置に通常用いられる公知のチェックフィルタを用いることができ、例えば、孔径が１〜５μｍのチェックフィルタが挙げられる。 The chlorine removing unit 13 is a unit that removes residual chlorine by filtering the raw water softened by the first water softening unit 12 with activated carbon. Specific examples include an activated carbon filter and an activated carbon filter filled with activated carbon.
The check filter 14 is a filter that checks the quality of raw water, and plays a role of removing fine particles of activated carbon, fine suspended matters in the raw water, and the like. As the check filter 14, a known check filter that is usually used in a purified water production apparatus can be used, and examples thereof include a check filter having a pore diameter of 1 to 5 μm.

第２軟水化手段１５は、残留塩素が除去された原水を下記ＮＦ膜（Ａ）で濾過して軟水化する手段である。
ＮＦ膜（Ａ）：濃度２０００ｍｇ／ＬのＮａＣｌ水溶液を、運転圧力０．５ＭＰａ、温度２５℃、ｐＨ６．５〜７．０、透過水の回収率１５％の条件で３０分間濾過したときのＮａＣｌの除去率（以下、「ＮａＣｌ除去率」という。）が７５〜９５％のＮＦ膜。ただし、前記運転圧力は、ＮＦ膜（Ａ）にかかる圧力を意味する。また、前記回収率は、ＮＦ膜（Ａ）に供給する前記ＮａＣｌ水溶液の量に対する透過水の量の割合を意味する。
ＮＦ膜（Ａ）を用いることにより、水質の良好な精製水を高い回収率で製造でき、ＲＯ膜の寿命の短縮も抑制できる。ＮＦ膜（Ａ）は、前記ＮａＣｌ除去率が８５〜９５％であることが好ましい。ＮａＣｌ除去率が前記範囲内であれば、水質の良好な精製水を高い回収率で製造することが容易になり、ＲＯ膜の寿命の短縮を抑制する効果も向上する。 The second water softening means 15 is a means for softening the raw water from which residual chlorine has been removed by filtering it through the following NF membrane (A).
NF membrane (A): NaCl solution obtained by filtering an aqueous NaCl solution having a concentration of 2000 mg / L for 30 minutes under the conditions of an operating pressure of 0.5 MPa, a temperature of 25 ° C., a pH of 6.5 to 7.0, and a permeate recovery rate of 15%. An NF film having a removal rate of 75 to 95% (hereinafter referred to as “NaCl removal rate”). However, the said operating pressure means the pressure concerning NF membrane (A). The recovery rate means the ratio of the amount of permeated water to the amount of the NaCl aqueous solution supplied to the NF membrane (A).
By using the NF membrane (A), purified water with good water quality can be produced with a high recovery rate, and shortening of the life of the RO membrane can also be suppressed. The NF film (A) preferably has a NaCl removal rate of 85 to 95%. If the NaCl removal rate is within the above range, it becomes easy to produce purified water with good water quality at a high recovery rate, and the effect of suppressing the shortening of the life of the RO membrane is also improved.

また、ＮＦ膜（Ａ）は、濃度２０００ｍｇ／ＬのＭｇＳＯ４水溶液を、運転圧力０．５ＭＰａ、温度２５℃、ｐＨ６．５〜７．０、透過水の回収率１５％の条件で３０分間濾過したときのＭｇＳＯ４の除去率（以下、「ＭｇＳＯ４除去率」という。）が９５％以上であることがより好ましい。前記ＭｇＳＯ４除去率が前記範囲内であれば、水質の良好な精製水を高い回収率で製造することがさらに容易になり、ＲＯ膜の寿命の短縮を抑制する効果も向上する。
ただし、前記運転圧力は、ＮＦ膜（Ａ）にかかる圧力を意味する。また、前記回収率は、ＮＦ膜（Ａ）に供給する前記ＭｇＳＯ４水溶液の量に対する透過水の量の割合を意味する。 In addition, the NF membrane (A) is a MgSO 4 aqueous solution having a concentration of 2000 mg / L, which is filtered for 30 minutes under the conditions of an operating pressure of 0.5 MPa, a temperature of 25 ° C., a pH of 6.5 to 7.0, and a permeate recovery rate of 15%. More preferably, the removal rate of MgSO 4 (hereinafter referred to as “MgSO 4 removal rate”) is 95% or more. If the MgSO 4 removal rate is within the above range, it becomes easier to produce purified water with good water quality at a high recovery rate, and the effect of suppressing the shortening of the life of the RO membrane is improved.
However, the said operating pressure means the pressure concerning NF membrane (A). In addition, the recovery rate means the ratio of the amount of permeate to the amount of the MgSO 4 solution supplied to NF membrane (A).

ＮＦ膜（Ａ）としては、ポリアミドを材質として用いた濾過膜（以下、「ポリアミド系ＮＦ膜」という。）が好ましい。ポリアミド系ＮＦ膜は、膜素材表面にマイナスの固定荷電を有するので、一般的なＮＦ膜である酢酸セルロース系、ポリスルホン系、ポリアクリロニトリル系に比べ、２価以上の陽イオン、特にカルシウムイオンやマグネシウムイオンなどの硬度成分の除去能力が高く、原水の軟水化に最適である。また、ポリアミド系ＮＦ膜は、イオン交換樹脂に比べ、原水の滞留が少ないので、細菌が繁殖しにくい。また、ポリアミド系ＮＦ膜は、２ｎｍより小さい粒子や高分子を除去できるので、エンドトキシンの除去も可能である。さらに、ポリアミド系ＮＦ膜は、一般的なＮＦ膜である酢酸セルロース系ＮＦ膜に比べて透過水の流量が多く、使用できるｐＨ範囲及び温度範囲が広く、耐薬品性が優れている。   As the NF membrane (A), a filtration membrane using polyamide as a material (hereinafter referred to as “polyamide-based NF membrane”) is preferable. Polyamide-based NF membranes have a negative fixed charge on the surface of the membrane material. Therefore, they are more than divalent cations, especially calcium ions and magnesium, compared to cellulose acetate-based, polysulfone-based, and polyacrylonitrile-based NF membranes. It has a high ability to remove hardness components such as ions and is ideal for softening raw water. In addition, the polyamide-based NF membrane has less retention of raw water than the ion exchange resin, so that bacteria hardly propagate. In addition, since the polyamide-based NF membrane can remove particles and polymers smaller than 2 nm, endotoxin can also be removed. Furthermore, the polyamide-based NF membrane has a larger flow rate of permeate than a cellulose acetate-based NF membrane, which is a general NF membrane, has a wide usable pH range and temperature range, and is excellent in chemical resistance.

第２軟水化手段１５としては、例えば、特開２００９−３９６９６号公報に記載のスパイラル型ＲＯ膜モジュールとほぼ同じ構造を有するモジュールであって、集水管の周りに、ＲＯ膜の代わりにＮＦ膜（Ａ）を巻き回した円柱状のＮＦ膜エレメントを、円筒状のケーシングに収納したスパイラル型ＮＦ膜モジュールが挙げられる。該ＮＦ膜モジュールは、原水入口から導入された原水を、ＮＦ膜（Ａ）を透過するＮＦ水（軟水）と、ＮＦ膜（Ａ）を透過しない濃縮水とに分離することができる。
第２軟水化手段１５は、塩素除去手段１４から送られてくる残留塩素が除去された原水を、ＮＦ膜（Ａ）を透過するＮＦ水と、ＮＦ膜を透過しない濃縮水とに分離できるものであれば前記スパイラル型ＮＦ膜モジュールに限定はされない。 As the second water softening means 15, for example, a module having substantially the same structure as the spiral RO membrane module described in JP 2009-39696 A, an NF membrane is used around the water collection pipe instead of the RO membrane. A spiral NF membrane module in which a columnar NF membrane element wound with (A) is housed in a cylindrical casing may be mentioned. The NF membrane module can separate the raw water introduced from the raw water inlet into NF water (soft water) that passes through the NF membrane (A) and concentrated water that does not pass through the NF membrane (A).
The second water softening means 15 is capable of separating the raw water from which residual chlorine has been removed sent from the chlorine removing means 14 into NF water that permeates the NF membrane (A) and concentrated water that does not permeate the NF membrane. If it is, it will not be limited to the said spiral type NF membrane module.

精製手段１６は、第２軟水化手段１５により軟水化されたＮＦ水をＲＯ膜で濾過して精製水を得る手段である。精製手段１６としては、例えば、特開２００９−３９６９６号公報に記載のスパイラル型ＲＯ膜モジュールが使用できる。ただし、精製手段１６は、第２軟水化手段１５から送られてくるＮＦ水を、ＲＯ膜を透過する精製水と、ＲＯ膜を透過しない濃縮水とに分離できるものであれば前記スパイラル型ＲＯ膜モジュールには限定されない。
また、ＲＯ膜モジュールにおけるＲＯ膜は、精製水製造装置に通常使用されるＲＯ膜を用いることができる。ＲＯ膜の材質としては、例えば、ポリアミド、ポリスルホン、酢酸セルロース、ポリアクリロニトリルなどが挙げられる。 The purification means 16 is a means for obtaining purified water by filtering the NF water softened by the second water softening means 15 through an RO membrane. As the purification means 16, for example, a spiral RO membrane module described in JP2009-39696A can be used. However, the refining means 16 is not limited to the spiral RO, as long as it can separate the NF water sent from the second water softening means 15 into purified water that permeates the RO membrane and concentrated water that does not permeate the RO membrane. The membrane module is not limited.
Moreover, the RO membrane normally used for the purified water manufacturing apparatus can be used for the RO membrane in the RO membrane module. Examples of the material of the RO membrane include polyamide, polysulfone, cellulose acetate, polyacrylonitrile, and the like.

精製水タンク１７の材質としては、精製水製造装置の精製水タンクに通常用いられる材質であればよく、例えば、塩化ビニル、ステンレスなどが挙げられる。
精製水タンク１７には、精製水タンク１７内の精製水を紫外線により殺菌処理する紫外線ランプ１７ａと、精製水タンク１７内の精製水を加熱する加温手段１７ｂと、精製水タンク１７内の精製水温度を計測する温度センサ（図示せず）とが設けられている。加温手段１７ｂとしては、電気ヒータなどが挙げられる。
また、精製水タンク１７は、精製水タンク１７内の液面レベルを感知する図示しない液面感知手段が設けられており、精製水量を調節できるようになっている。液面感知手段としては、例えば、レベルスイッチ、フロートセンサー、ボールタップなどが挙げられる。 The material of the purified water tank 17 may be any material that is usually used for a purified water tank of a purified water production apparatus. Examples thereof include vinyl chloride and stainless steel.
The purified water tank 17 includes an ultraviolet lamp 17a for sterilizing the purified water in the purified water tank 17 with ultraviolet rays, a heating means 17b for heating the purified water in the purified water tank 17, and a purified water in the purified water tank 17. A temperature sensor (not shown) for measuring the water temperature is provided. Examples of the heating means 17b include an electric heater.
The purified water tank 17 is provided with a liquid level sensing means (not shown) that senses the liquid level in the purified water tank 17 so that the amount of purified water can be adjusted. Examples of the liquid level sensing means include a level switch, a float sensor, and a ball tap.

送水ポンプ４１〜４５は、精製水製造装置で通常使用されるポンプを使用することができ、例えば、多段渦巻ポンプ、プランジャーポンプなどの高圧ポンプが挙げられる。また、送水ポンプ４１〜４５は、インバータ制御により圧力変動が可能なものであることが好ましい。
送水ポンプ４２がインバータ制御できるものであれば、精製水製造装置１の稼動を開始する際に、スロースタート方式（徐々に圧力を上昇させる方式）を採用することで、ＮＦ膜（Ａ）に加わる負担を軽減することができる。同様に、送水ポンプ４３がインバータ制御できるものであれば、精製水製造装置１の稼動を開始する際に、スロースタート方式を採用することで、ＲＯ膜に加わる負担を軽減できる。送水ポンプ４４がインバータ制御できるものであれば、精製水を末端機器に送水する必要のない夜間、休日などににおいて、精製水が滞留して汚染されることを防ぐために精製水循環ライン５７内で精製水を循環させる際、その圧力を末端機器に送水する際の圧力よりも低く設定することができる。 As the water supply pumps 41 to 45, a pump usually used in a purified water production apparatus can be used, and examples thereof include high-pressure pumps such as a multistage centrifugal pump and a plunger pump. Moreover, it is preferable that the water pumps 41-45 can change a pressure by inverter control.
If the water pump 42 can be controlled by an inverter, when starting the operation of the purified water production apparatus 1, a slow start method (a method of gradually increasing the pressure) is adopted to add to the NF membrane (A). The burden can be reduced. Similarly, if the water pump 43 can be controlled by an inverter, the load applied to the RO membrane can be reduced by adopting the slow start method when starting the operation of the purified water production apparatus 1. If the water pump 44 can be controlled by an inverter, the purified water is purified in the purified water circulation line 57 in order to prevent the purified water from staying and contaminated at night and on holidays when it is not necessary to send the purified water to the terminal equipment. When water is circulated, the pressure can be set lower than the pressure when water is supplied to the terminal device.

以下、精製水製造装置１による精製水の製造について説明する。
精製水の製造に用いる原水としては、例えば、水道水、地下水などの市水を用いることができる。
精製水の製造を停止している状態から精製水の製造を開始する際には、まず原水タンク１１から第２軟水化手段１５までに存在している水を抜水する（初期抜水工程）。排水ライン６８の電動弁３８を開き、その他の弁を閉じた状態として、送水ポンプ４１、４２を稼動させる。原水は、原水タンク１１から送水され、第１軟水化手段１２、塩素除去手段１３、チェックフィルタ１４及び第２軟水化手段１５を順次通過した後、送水ライン５５から排水ライン６８を通じて排水される。それと同時に、精製水の製造停止時に原水タンク１１から第２軟水化手段１５までに存在していた水が、排水ライン６８から排水される。この初期抜水工程は、３分程度行えばよい。 Hereinafter, the production of purified water by the purified water production apparatus 1 will be described.
As raw water used for manufacture of purified water, city water, such as tap water and ground water, can be used, for example.
When starting production of purified water from a state where production of purified water is stopped, first, water existing from the raw water tank 11 to the second water softening means 15 is drained (initial draining step). . The water supply pumps 41 and 42 are operated with the electric valve 38 of the drainage line 68 opened and the other valves closed. The raw water is fed from the raw water tank 11 and sequentially passes through the first water softening means 12, the chlorine removing means 13, the check filter 14 and the second water softening means 15, and then drained from the water feed line 55 through the drain line 68. At the same time, the water existing from the raw water tank 11 to the second water softening means 15 when the production of purified water is stopped is drained from the drain line 68. This initial draining step may be performed for about 3 minutes.

次に、第２軟水化手段１５から精製手段１６までに存在している水を抜水する（一次抜水工程）。電動弁３８を閉じ、電動弁２１を開いて、電動弁２３を送水ライン５６と精製水返送ライン６５が連通した状態にして、送水ポンプ４１、４２、４３を稼動させる。原水は、原水タンク１１から原水が送水され、第１軟水化手段１２、塩素除去手段１３、チェックフィルタ１４、第２軟水化手段１５及び精製手段１６を順次通過した後、精製水が送水ライン５６、精製水返送ライン６５、濃縮水返送ライン５９を通過して原水タンク１１に回収される。それと同時に、精製水の製造停止時に第２軟水化手段１５から精製手段１６までに存在していた水が原水タンク１１に回収される。この一次抜水工程は、１分程度行えばよい。
このような、初期抜水工程と一次抜水工程を行うことにより、仮に精製水の製造を停止していたときに、原水タンク１１から精製手段１６までの間で、滞留水に細菌が繁殖したとしても、その細菌が精製水タンク１７に混入することを防止できる。 Next, the water existing from the second water softening means 15 to the purification means 16 is drained (primary draining step). The motor-operated valve 38 is closed, the motor-operated valve 21 is opened, and the water-feed pumps 41, 42, 43 are operated with the motor-operated valve 23 in a state where the water-feed line 56 and the purified water return line 65 are in communication. The raw water is fed from the raw water tank 11 and sequentially passes through the first water softening means 12, the chlorine removing means 13, the check filter 14, the second water softening means 15 and the purification means 16, and then the purified water is supplied to the water supply line 56. Then, it passes through the purified water return line 65 and the concentrated water return line 59 and is collected in the raw water tank 11. At the same time, the water existing from the second water softening means 15 to the purification means 16 when the production of purified water is stopped is recovered in the raw water tank 11. This primary draining step may be performed for about 1 minute.
By performing the initial draining step and the primary draining step as described above, when the production of purified water was stopped, bacteria propagated in the accumulated water between the raw water tank 11 and the purification means 16. However, it is possible to prevent the bacteria from entering the purified water tank 17.

一次抜水工程の後、精製水の製造を開始する（精製水製造工程）。
原水の温度は、得られる精製水の水質が向上する点から、２０〜２５℃が好ましい。原水の温度は、原水タンク１１に設置された加温手段により調整できる。 After the primary draining process, the production of purified water is started (purified water manufacturing process).
The temperature of the raw water is preferably 20 to 25 ° C. from the viewpoint of improving the quality of the purified water obtained. The temperature of the raw water can be adjusted by a heating means installed in the raw water tank 11.

電動弁３８、弁３９及び弁４０を閉じ、電動弁２３を送水ライン５６と精製水返送ライン６５が連通しない状態に切り換え、他の各電動弁を開く。
原水タンク１１から送水ライン５１を通って供給される原水は、送水ポンプ４１によって加圧された後、第１軟水化手段１２、塩素除去手段１３及びチェックフィルタ１４に順次送られる。第１軟水化手段１２では、イオン交換樹脂によりＣａ２＋、Ｍｇ２＋などが吸着され、代わりにＮａ＋が放出されて軟水化される。塩素除去手段１３では、第１軟水化手段１２で軟水化された原水が活性炭で濾過され、残留塩素が除去される。チェックフィルタ１４では、原水中に含まれている細かい浮遊物などが除去される。 The motorized valve 38, the valve 39 and the valve 40 are closed, the motorized valve 23 is switched to a state where the water supply line 56 and the purified water return line 65 do not communicate with each other, and the other motorized valves are opened.
The raw water supplied from the raw water tank 11 through the water supply line 51 is pressurized by the water supply pump 41 and then sequentially sent to the first water softening means 12, the chlorine removal means 13 and the check filter 14. In the first water softening unit 12, Ca 2+ by ion exchange resins, such as Mg 2+ are adsorbed, Na + is softened is released instead. In the chlorine removing means 13, the raw water softened by the first water softening means 12 is filtered with activated carbon to remove residual chlorine. The check filter 14 removes fine floating matters contained in the raw water.

送水ポンプ４１による加圧は、原水が第１軟水化手段１２、塩素除去手段１３及びチェックフィルタ１４を通過する際の圧力損失を考慮に入れ、送水ポンプ４２のポンプ入口で原水の圧力が０．１〜０．４ＭＰａとなるように加圧することが好ましい。   The pressurization by the water supply pump 41 takes into account the pressure loss when the raw water passes through the first softening means 12, the chlorine removal means 13 and the check filter 14, and the pressure of the raw water at the pump inlet of the water supply pump 42 is 0. It is preferable to pressurize so that it may become 1-0.4 MPa.

チェックフィルタ１４を通過した原水は、送水ポンプ４２によって加圧された後に第２軟水化手段１５に送られ、その一部がＮＦ膜（Ａ）を透過して軟水化される。ＮＦ膜（Ａ）を透過しなかった残りの原水は濃縮水となる。該濃縮水は、その一部が濃縮水返送ライン５８を通って送水ライン５４における送水ポンプ４２の上流側に戻され、原水として再利用される。また、残りの濃縮水は、排水ライン６７から精製水製造装置１外に排出される。第２軟水化手段１５の運転圧力（ＮＦ膜（Ａ）にかかる圧力）は、送水ポンプ４２と、排水ライン６７に設けられた流量調整弁３７によって調整できる。   The raw water that has passed through the check filter 14 is pressurized by the water supply pump 42 and then sent to the second water softening means 15, and a part of the raw water passes through the NF membrane (A) and is softened. The remaining raw water that has not passed through the NF membrane (A) becomes concentrated water. A part of the concentrated water passes through the concentrated water return line 58 and is returned to the upstream side of the water supply pump 42 in the water supply line 54 and reused as raw water. The remaining concentrated water is discharged out of the purified water production apparatus 1 from the drain line 67. The operating pressure of the second water softening means 15 (pressure applied to the NF membrane (A)) can be adjusted by the water supply pump 42 and the flow rate adjustment valve 37 provided in the drain line 67.

第２軟水化手段１５の運転圧力（ＮＦ膜（Ａ）にかかる圧力）は、０．５〜０．８ＭＰａが好ましい。第２軟水化手段１５の運転圧力が前記範囲内であれば、水質を低下させすぎずにＮＦ水の流量を増加させることが容易になる。
ＮＦ膜（Ａ）を透過する透過水の回収率（以下、「ＮＦ回収率」という。）、すなわち処理する原水量に対するＮＦ水量の割合は、７０〜８５％が好ましい。精製水製造装置１では、第１軟水化手段１５の前段に第１軟水化手段１２が備えられているため、ＮＦ回収率を７０％以上としてもＮＦ膜（Ａ）にかかる負担が大きくなりすぎることが抑制される。ＮＦ回収率が７０％以上であれば、精製水の回収率、すなわち処理する原水量に対して得られる精製水量の割合が向上する。 The operating pressure of the second water softening means 15 (pressure applied to the NF membrane (A)) is preferably 0.5 to 0.8 MPa. If the operating pressure of the second water softening means 15 is within the above range, it becomes easy to increase the flow rate of NF water without reducing the water quality too much.
The recovery rate of the permeated water that passes through the NF membrane (A) (hereinafter referred to as “NF recovery rate”), that is, the ratio of the NF water amount to the raw water amount to be treated is preferably 70 to 85%. In the purified water production apparatus 1, since the first water softening means 12 is provided in front of the first water softening means 15, the burden on the NF membrane (A) becomes too large even if the NF recovery rate is 70% or more. It is suppressed. When the NF recovery rate is 70% or more, the recovery rate of purified water, that is, the ratio of the amount of purified water obtained to the amount of raw water to be processed is improved.

第２軟水化手段１５によって軟水化されたＮＦ水は、送水ライン５５の送水ポンプ４３によって加圧され、精製手段１６に送られる。精製手段１６に供給されたＮＦ水は、その一部がＲＯ膜を透過して精製水となり、送水ライン５６を通って精製水タンク１７に送られて貯留される。ＲＯ膜を透過しなかった残りのＮＦ水は濃縮水となる。精製水製造装置１においては、ＲＯ膜を透過しなかった濃縮水が、濃縮水返送ライン５９を通して原水タンク１１に返送されて原水と混合される。これにより、使用する原水のうち、濃縮水として排水される量を減少するので、精製水の回収率が向上する。
精製手段１６の運転圧力は、送水ポンプ４３と、濃縮水返送ライン５９に設けられた流量調整弁２７によって調節できる。 The NF water softened by the second water softening means 15 is pressurized by the water feed pump 43 of the water feed line 55 and sent to the purification means 16. Part of the NF water supplied to the purification means 16 passes through the RO membrane to become purified water, and is sent to the purified water tank 17 through the water supply line 56 to be stored. The remaining NF water that has not permeated the RO membrane becomes concentrated water. In the purified water production apparatus 1, the concentrated water that has not passed through the RO membrane is returned to the raw water tank 11 through the concentrated water return line 59 and mixed with the raw water. Thereby, since the quantity discharged | emitted as concentrated water among the raw | natural water to be used is reduced, the recovery rate of purified water improves.
The operating pressure of the purifying means 16 can be adjusted by the water supply pump 43 and the flow rate adjusting valve 27 provided in the concentrated water return line 59.

精製手段１６の運転圧力は、０．５〜１．０ＭＰａが好ましい。精製手段１６の運転圧力が前記範囲内であれば、水質を低下させずに精製水の流量を増加させることが容易になる。   The operating pressure of the purification means 16 is preferably 0.5 to 1.0 MPa. If the operating pressure of the purifying means 16 is within the above range, it becomes easy to increase the flow rate of purified water without reducing the water quality.

精製水製造装置１においては、ＲＯ膜を透過しなかった濃縮水のうち濃縮水返送ライン５９を通じて返送される濃縮水の割合は、９０％以上が好ましく、９５％以上がより好ましく、１００％が特に好ましい。精製水製造装置１は、精製手段１６の前段に、第１軟水化手段１２、塩素除去手段１３に加えて、各種イオンの除去効率が優れているＮＦ膜（Ａ）を有する第２軟水化手段１５を備えられているため、精製手段１６に供給されるＮＦ水の水質が優れている。そのため、精製手段１６において、ＲＯ膜を透過しなかった濃縮水は、その不純物が濃縮されているにもかかわらず、原水タンク１１に貯留される処理前の原水よりも水質が優れたものとなる。したがって、ＲＯ膜を透過しなかった濃縮水の９０％以上を原水タンク１１に戻して原水と混合させても、原水タンク１１に貯留される原水の水質が低下することはなく、むしろ希釈によって原水の水質が向上する。
また、前記のように、ＲＯ膜を透過しなかった濃縮水を原水タンク１１に戻して混合することで原水タンク１１内の原水の水質が向上するので、最終的に精製手段１６のＲＯ膜を透過して得られる精製水の水質も向上する。加えて、処理する原水の水質が向上することで、ＲＯ膜にかかる負担も軽減されるため、ＲＯ膜の寿命短縮も抑制できる。 In the purified water production apparatus 1, the ratio of the concentrated water returned through the concentrated water return line 59 in the concentrated water that has not passed through the RO membrane is preferably 90% or more, more preferably 95% or more, and 100%. Particularly preferred. The purified water production apparatus 1 includes a second water softening means having an NF membrane (A) excellent in the removal efficiency of various ions in addition to the first water softening means 12 and the chlorine removing means 13 in the preceding stage of the purification means 16. 15, the quality of the NF water supplied to the purification means 16 is excellent. Therefore, in the refining means 16, the concentrated water that has not permeated through the RO membrane has a water quality superior to that of the raw water before treatment stored in the raw water tank 11, even though the impurities are concentrated. . Therefore, even if 90% or more of the concentrated water that has not permeated the RO membrane is returned to the raw water tank 11 and mixed with the raw water, the quality of the raw water stored in the raw water tank 11 does not deteriorate. The water quality is improved.
In addition, as described above, the concentrated water that has not permeated the RO membrane is returned to the raw water tank 11 and mixed to improve the quality of the raw water in the raw water tank 11. The quality of purified water obtained by permeation is also improved. In addition, since the load on the RO membrane is reduced by improving the quality of the raw water to be treated, shortening of the life of the RO membrane can be suppressed.

また、ＲＯ膜を透過しなかった濃縮水の全てを原水タンク１１に戻さない場合には、残りの濃縮水は、濃縮水返送ライン６０を通じて、送水ライン５５における電動弁２１と送水ポンプ４３の間に戻して再利用する。また、なんらかの問題が生じて、ＲＯ膜を透過しなかった濃縮水を、濃縮水返送ライン５９を通じて原水タンク１１に戻せなくなったときは、その濃縮水を排水ライン６９から排水するようにする。   Further, when not all the concentrated water that has passed through the RO membrane is returned to the raw water tank 11, the remaining concentrated water passes through the concentrated water return line 60 between the motor operated valve 21 and the water feed pump 43 in the water feed line 55. Return to and reuse. Further, when some problem occurs and the concentrated water that has not passed through the RO membrane cannot be returned to the raw water tank 11 through the concentrated water return line 59, the concentrated water is drained from the drain line 69.

精製水タンク１７が精製水で満水になった後は、送水ポンプ４１、４２が停止し、電動弁２１が閉じられ、送水ポンプ４５が稼動する。これにより、精製水タンク１７の精製水が、精製水返送ライン６２を通じて送水ライン５５における電動弁２１と送水ポンプ４３の間に戻され、精製手段１６を通じて精製水タンク１７に戻されて循環する（循環工程）。このように、精製水を循環させることにより、精製水の滞留によって細菌が繁殖することが防止される。また、精製水タンク１７内では、紫外線ランプ１７ａにより紫外線を照射することにより、貯留された精製水が殺菌処理される。   After the purified water tank 17 is filled with purified water, the water pumps 41 and 42 are stopped, the motor-operated valve 21 is closed, and the water pump 45 is operated. As a result, the purified water in the purified water tank 17 is returned between the motor-operated valve 21 and the water pump 43 in the water supply line 55 through the purified water return line 62, and returned to the purified water tank 17 through the purification means 16 and circulated ( Circulation process). Thus, by circulating the purified water, bacteria are prevented from breeding due to the retention of the purified water. In the purified water tank 17, the stored purified water is sterilized by irradiating with ultraviolet rays from the ultraviolet lamp 17a.

従来のＲＯ膜を単独で用いる精製水製造装置では、ＲＯ膜の一次側に存在する水の水質が悪いため、その水を一旦排水した後に精製水の循環が行われていた。つまり、精製水製造装置１で言えば、精製水を循環させる前に、排水ライン６９から精製手段１６のＲＯ膜の一次側の水を排水してから、前記精製水の循環を行っていた。しかし、精製水製造装置１では、第１軟水化手段１２及び塩素除去手段１３に加えて、各種イオンの除去効率が優れたＮＦ膜（Ａ）を有する第２軟水化手段１５を有しているため、精製手段１６のＲＯ膜の一次側のＮＦ水の水質が良好である。そのため、ＲＯ膜の一次側の水を排水せずに精製水を循環させることができ、コストが削減できる。   In a purified water production apparatus that uses a conventional RO membrane alone, the quality of the water present on the primary side of the RO membrane is poor, and thus the purified water is circulated after the water has been drained. That is, in the purified water production apparatus 1, before the purified water is circulated, the water on the primary side of the RO membrane of the purification means 16 is drained from the drainage line 69 and then the purified water is circulated. However, in the purified water production apparatus 1, in addition to the first water softening means 12 and the chlorine removal means 13, the purified water production apparatus 1 has a second water softening means 15 having an NF membrane (A) excellent in removal efficiency of various ions. Therefore, the quality of NF water on the primary side of the RO membrane of the purification means 16 is good. Therefore, the purified water can be circulated without draining the water on the primary side of the RO membrane, and the cost can be reduced.

夜間など精製水の製造を停止しているときには、送水ポンプ４４を稼動させ、精製水タンク１７から精製水循環ライン５７に精製水を取り出し、再び精製水タンク１７に戻して、精製水を循環させて絶えず流動状態とすることが好ましい。これにより、精製水が滞留して細菌が繁殖することを抑制できる。   When the production of purified water is stopped, such as at night, the water pump 44 is operated, the purified water is taken out from the purified water tank 17 to the purified water circulation line 57, returned to the purified water tank 17 again, and the purified water is circulated. It is preferable to make it a fluid state constantly. Thereby, it can suppress that purified water stagnates and bacteria propagate.

また、精製水製造装置１においては、休日や夜間などの精製水の使用がない時間帯に、ＮＦ膜（Ａ）を洗浄するフラッシング工程を行うことが好ましい。該フラッシング工程を実施することにより、ＮＦ膜（Ａ）の劣化を抑制することが容易になり、その寿命をより長くすることができる。
該フラッシング工程では、電動弁２１を閉じた状態でポンプ４１、４２を稼動させ、原水を原水タンク１１から第１軟水化手段１２、塩素除去手段１３、チェックフィルタ１４及び第２軟水化手段１５へと送り、第２軟水化手段１５を透過したＮＦ水をＮＦ水返送ライン６１、濃縮水返送ライン５９を通じて原水タンク１１に戻す。第２軟水化手段をフラッシングして洗浄した洗浄水は、排水ライン６７から排水する。フラッシング工程の実施時間は特に限定されず、１０分程度行えばよい。 Moreover, in the purified water manufacturing apparatus 1, it is preferable to perform the flushing process which wash | cleans NF film | membrane (A) in the time slot | zones when purified water is not used, such as a holiday or night. By performing the flushing step, it becomes easy to suppress the deterioration of the NF film (A), and the lifetime can be further extended.
In the flushing step, the pumps 41 and 42 are operated with the motor operated valve 21 closed, and the raw water is supplied from the raw water tank 11 to the first water softening means 12, the chlorine removing means 13, the check filter 14 and the second water softening means 15. The NF water that has passed through the second water softening means 15 is returned to the raw water tank 11 through the NF water return line 61 and the concentrated water return line 59. The washing water washed by flushing the second water softening means is drained from the drain line 67. The execution time of the flushing step is not particularly limited, and may be performed for about 10 minutes.

また、休日や夜間などの精製水の使用がない時間帯には、精製水製造装置１内を熱水処理によって消毒すること（熱水処理工程）が好ましい。
熱水処理工程は、精製水製造装置１内における下記経路（ａ）〜（ｄ）のいずれかに精製水を循環させながら、精製水タンク１７内の精製水を加温手段１７ｂによって加熱することにより行われる。
（ａ）電動弁３２によって精製水返送ライン６２と精製水返送ライン６３が連通され、電動弁３３によって精製水返送ライン６３と精製水返送ライン６４が連通され、加熱した精製水が、精製タンク１７から、精製水返送ライン６２、精製水返送ライン６３、精製水返送ライン６４を通じて送水ライン５１に送られ、第１軟水化手段１２、塩素除去手段１３、チェックフィルタ１４、第２軟水化手段１５及び精製手段１６を通じて精製水タンク１７に戻される経路。
（ｂ）電動弁３２によって精製水返送ライン６２と精製水返送ライン６３が連通され、電動弁３３によって精製水返送ライン６３と精製水返送ライン６４が連通しないようにされ、加熱した精製水が、精製タンク１７から、精製水返送ライン６２、精製水返送ライン６３を通じて送水ライン５４に送られ、第２軟水化手段１５及び精製手段１６を通じて精製水タンク１７に戻される経路。
（ｃ）電動弁３２によって精製水返送ライン６２と精製水返送ライン６３が連通しないようにされ、加熱した精製水が、精製タンク１７から精製水返送ライン６２を通じて送水ライン５５に送られ、精製手段１６を通じて精製水タンク１７に戻される経路。
（ｄ）加熱した精製水が、精製タンク１７から精製水循環ライン５７に取り出されて、再び精製水タンク１７に戻される経路。 Moreover, it is preferable to disinfect the inside of the purified water production apparatus 1 by hot water treatment (hot water treatment step) in a time zone where purified water is not used such as a holiday or at night.
In the hot water treatment step, the purified water in the purified water tank 17 is heated by the heating means 17b while circulating the purified water in any of the following paths (a) to (d) in the purified water production apparatus 1. Is done.
(A) The purified water return line 62 and the purified water return line 63 are communicated with each other by the electric valve 32, and the purified water return line 63 and the purified water return line 64 are communicated with each other through the electric valve 33. Are sent to the water supply line 51 through the purified water return line 62, the purified water return line 63, and the purified water return line 64. The first water softening means 12, the chlorine removal means 13, the check filter 14, the second water softening means 15 and A path returned to the purified water tank 17 through the purification means 16.
(B) The purified water return line 62 and the purified water return line 63 are communicated with each other by the electric valve 32, and the purified water return line 63 and the purified water return line 64 are prevented from being communicated with each other by the electric valve 33. A route that is sent from the purification tank 17 to the water supply line 54 through the purified water return line 62 and the purified water return line 63 and returned to the purified water tank 17 through the second water softening means 15 and the purification means 16.
(C) The purified water return line 62 and the purified water return line 63 are prevented from communicating with each other by the electric valve 32, and the heated purified water is sent from the purification tank 17 to the water supply line 55 through the purified water return line 62 and purified. 16 is a path that is returned to the purified water tank 17 through 16.
(D) A route in which heated purified water is taken out from the purification tank 17 to the purified water circulation line 57 and returned to the purified water tank 17 again.

精製水を加熱する際は、紫外線ランプ１７ａによる精製水タンク１７内の精製水への紫外線の照射は停止することが好ましい。加熱しながらの紫外線ランプの照射はランプ寿命を短命にする傾向がある。   When heating the purified water, it is preferable to stop the irradiation of the purified water in the purified water tank 17 by the ultraviolet lamp 17a. Irradiation with an ultraviolet lamp while heating tends to shorten the lamp life.

熱水処理工程における精製水の温度は、６０〜９５℃が好ましく、８０〜９５℃がより好ましい。熱水処理時の精製水の温度が高いほど、精製水製造装置１内における各部材の連結部部分の熱水処理が容易になる。また、熱水処理時の精製水の温度が低いほど、精製水製造装置１の熱劣化を抑制しやすい。
精製水の加熱は、各電動弁及び送水ポンプ、加温手段１７ｂなどの駆動を制御することにより、５℃／分以下の速度で昇温させることが好ましい。精製水の加熱速度が５℃／分以下であれば、ＮＦ膜（Ａ）、ＲＯ膜などが熱劣化することを抑制しやすい。
また、熱水処理工程では、精製水製造装置１内で加熱した精製水を透析装置などの末端機器に送水し、末端機器を熱水処理するようにしてもよい。これにより、透析装置内などで繁殖した菌や、エンドトキシン（発熱性物質）を低減することが容易になる。 60-95 degreeC is preferable and the temperature of the purified water in a hydrothermal treatment process has more preferable 80-95 degreeC. The higher the temperature of the purified water during the hot water treatment, the easier the hot water treatment of the connecting portion of each member in the purified water production apparatus 1 is. Moreover, it is easy to suppress the thermal deterioration of the purified water manufacturing apparatus 1 so that the temperature of the purified water at the time of a hot water process is low.
The heating of the purified water is preferably performed at a rate of 5 ° C./min or less by controlling the driving of each electric valve, the water pump, the heating means 17b and the like. If the heating rate of purified water is 5 ° C./min or less, it is easy to suppress thermal degradation of the NF membrane (A), the RO membrane, and the like.
In the hot water treatment step, purified water heated in the purified water production apparatus 1 may be sent to a terminal device such as a dialysis device, and the terminal device may be subjected to hot water treatment. Thereby, it becomes easy to reduce the germs and endotoxins (pyrogenic substances) that have propagated in the dialysis machine.

なお、熱水処理の代わりに、薬液（消毒剤）による消毒処理が行えるようになっていてもよく、薬液を混合した精製水を加熱した熱水消毒液を循環させて消毒処理を行うものであってもよい。   In addition, instead of hot water treatment, disinfection treatment with a chemical solution (disinfectant) may be performed, and a hot water disinfection solution heated with purified water mixed with a chemical solution is circulated to perform disinfection treatment. There may be.

以上説明した各工程は、精製水製造装置１に制御部を設けて、該制御部によって各部分の動作を制御することにより行うことが好ましい。
前記制御部は、処理部と、インターフェイス部と、カレンダータイマとから概略構成される。制御部は、初期抜水工程、一次抜水工程、精製水製造工程、循環工程、フラッシング工程及び熱水処理工程の各工程を制御し、かつ、これらの工程をカレンダータイマに設定された任意の日時に実施できるものである。 It is preferable to perform each process demonstrated above by providing a control part in the purified water manufacturing apparatus 1, and controlling operation | movement of each part by this control part.
The control unit is generally composed of a processing unit, an interface unit, and a calendar timer. The control unit controls each process of the initial draining process, the primary draining process, the purified water manufacturing process, the circulation process, the flushing process, and the hot water treatment process, and these processes are arbitrarily set in the calendar timer. It can be implemented day and time.

前記カレンダータイマは、年月日および時刻を管理する時計部と、精製水製造装置の運転スケジュールを記憶する記憶部とを具備してなり、記憶部に記憶された設定日時に電気信号を発信できるようにされている。
前記インターフェイス部は、各ラインに設けられたすべての弁、送水ポンプと処理部との間を電気的に接続するものである。
前記処理部は、カレンダータイマからの電気信号や処理部に入力された操作信号に基づいて、各ラインに設けられた弁の開閉および送水ポンプの運転の開始、停止を制御するものである。 The calendar timer includes a clock unit that manages date and time, and a storage unit that stores an operation schedule of the purified water production apparatus, and can transmit an electrical signal at a set date and time stored in the storage unit. Has been.
The interface unit electrically connects all valves, water pumps, and processing units provided in each line.
The processing unit controls the opening and closing of valves provided in each line and the start and stop of the operation of the water pump based on the electrical signal from the calendar timer and the operation signal input to the processing unit.

なお、この処理部は、専用のハードウエアにより実現されるものであってもよく、メモリおよび中央演算装置（ＣＰＵ）によって構成され、処理部の機能を実現するためのプログラムをメモリにロードして実行することにより、その機能を実現させるものであってもよい。
また、制御部には、周辺機器として、入力装置、表示装置などが接続される。ここで、入力装置とは、ディスプレイタッチパネル、スイッチパネル、キーボードなどの入力デバイスのことをいい、表示装置とは、ＣＲＴや液晶表示装置をいう。 The processing unit may be realized by dedicated hardware, and is configured by a memory and a central processing unit (CPU). A program for realizing the function of the processing unit is loaded into the memory. The function may be realized by executing the function.
In addition, an input device, a display device, and the like are connected to the control unit as peripheral devices. Here, the input device refers to an input device such as a display touch panel, a switch panel, or a keyboard, and the display device refers to a CRT or a liquid crystal display device.

以上説明した精製水製造装置１は、ＲＯ膜を透過しなかった濃縮水を返送して処理前の原水と混合して再利用することで、精製水の回収率が向上する。また、精製手段１６のＲＯ膜の前段に、第１軟水化手段１２、塩素除去手段１３に加えて、各種イオンの除去効率が高いＮＦ膜（Ａ）を有する第２軟水化手段１５を採用することにより、ＲＯ膜を透過しなかった濃縮水を返送して再利用しても、原水の水質が低下せずＲＯ膜にかかる負担が増加しない。加えて、ＲＯ膜を透過しなかった濃縮水を混合することで処理前の原水の水質が向上するため、最終的に得られる精製水の水質も向上する。このように、精製水製造装置１では、ＲＯ膜の寿命が短くなることを抑制しつつ、優れた水質の精製水を高い回収率で安価に製造できる。特に、ＲＯ膜を透過しなかった濃縮水の９０％以上を返送して再利用することで、従来約６０〜７０％であった精製水の回収率を、約７５〜９０％程度にまで向上させることができると考えられる。   The purified water manufacturing apparatus 1 demonstrated above improves the recovery rate of purified water by returning the concentrated water which did not permeate | transmit RO membrane, mixing with the raw water before a process, and reusing. Further, in addition to the first water softening means 12 and the chlorine removing means 13, the second water softening means 15 having an NF membrane (A) with high removal efficiency of various ions is employed in the stage before the RO membrane of the purification means 16. Thus, even if the concentrated water that has not permeated the RO membrane is returned and reused, the quality of the raw water does not deteriorate and the burden on the RO membrane does not increase. In addition, since the quality of the raw water before the treatment is improved by mixing the concentrated water that has not passed through the RO membrane, the quality of the purified water finally obtained is also improved. As described above, the purified water production apparatus 1 can produce purified water with excellent water quality at a high recovery rate at a low cost while suppressing the life of the RO membrane from being shortened. In particular, by returning 90% or more of the concentrated water that did not permeate the RO membrane and reusing it, the recovery rate of purified water, which was previously about 60-70%, is improved to about 75-90%. It is thought that it can be made.

なお、本発明の精製水製造装置は、前述したイオン交換樹脂を有する第１軟水化手段、活性炭を有する塩素除去手段、ＮＦ膜（Ａ）を有する第２軟水化手段、ＲＯ膜を有する精製手段、及びＲＯ膜を透過しなかった濃縮水を第１軟水化手段の一次側に返送して原水と混合する濃縮水返送ラインを備えているものであれば、前述した精製水製造装置１には限定されない。
例えば、チェックフィルタ１４を有していない精製水製造装置であってもよい。また、透析機器などの末端機器と連動するようになっていてもよい。 The purified water production apparatus of the present invention includes the first water softening means having the ion exchange resin, the chlorine removing means having activated carbon, the second water softening means having the NF membrane (A), and the purification means having the RO membrane. In addition, the purified water production apparatus 1 described above includes a concentrated water return line that returns concentrated water that has not passed through the RO membrane to the primary side of the first water softening means and mixes it with raw water. It is not limited.
For example, the purified water manufacturing apparatus which does not have the check filter 14 may be sufficient. Further, it may be linked with a terminal device such as a dialysis device.

また、前述した精製水製造装置１では、ＲＯ膜を透過しなかった濃縮水は濃縮水返送ライン５９によって原水タンク１１に返送される形態であったが、該濃縮水を返送する位置は原水タンク１１には限定されない。例えば、ＲＯ膜を透過しなかった濃縮水を、原水タンク１１と第１軟水化手段１２の間に返送するものであってもよく、第１軟水化手段１２と塩素除去手段１３とチェックフィルタ１４の間に返送するものであってもよく、チェックフィルタ１４と第２軟水化手段の間に返送するものであってもよい。ただし、得られる優れた水質の精製水が得られやすく、ＲＯ膜の寿命の短縮を抑制しやすい点から、ＲＯ膜を透過しなかった濃縮水を、第１軟水化手段１２の一次側の原水に混合することが好ましく、原水の温度調節、処理量の調節等が容易になる点から、ＲＯ膜を透過しなかった濃縮水を原水タンク１１に返送する前記精製水製造装置１がより好ましい。   Moreover, in the purified water production apparatus 1 described above, the concentrated water that did not permeate the RO membrane was returned to the raw water tank 11 by the concentrated water return line 59, but the position where the concentrated water is returned is the raw water tank. It is not limited to 11. For example, the concentrated water that has not passed through the RO membrane may be returned between the raw water tank 11 and the first water softening means 12, and the first water softening means 12, the chlorine removal means 13, and the check filter 14 may be used. May be returned between the check filter 14 and the second water softening means. However, the concentrated water that did not permeate the RO membrane is used as the primary water on the primary side of the first water softening means 12 because it is easy to obtain purified water having excellent water quality and it is easy to suppress the shortening of the life of the RO membrane. The purified water production apparatus 1 that returns the concentrated water that has not permeated through the RO membrane to the raw water tank 11 is more preferable because it is easy to adjust the temperature of the raw water, adjust the treatment amount, and the like.

以下、実施例を示して本発明を詳細に説明する。ただし、本発明は以下の記載によっては限定されない。
本実施例における水質の測定は、以下に示す方法で行った。
［水質の測定］
水質の測定は、電気伝導度計により導電率（単位：ｍＳ／ｍ）を測定することにより行った。
導電率とは電気の流れ易さを表す指標で、水中に各種イオンが多く含まれているほど導電率は高くなる。導電率が低ければ低いほど、不純物を含まない良質な水である。 Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following description.
The water quality in this example was measured by the following method.
[Measurement of water quality]
The water quality was measured by measuring the conductivity (unit: mS / m) with an electric conductivity meter.
The conductivity is an index representing the ease of flow of electricity, and the more the various ions are contained in water, the higher the conductivity. The lower the conductivity, the better the water without impurities.

［例１］
図１に例示した精製水製造装置１を用いて、精製水を製造した。第１軟水化手段１２として、軟水器（Ｎａ型樹脂４０Ｌ）を用い、塩素除去手段１３として活性炭フィルタ（濾過精度５μｍ以下、繊維状活性炭）を用い、チェックフィルタ１４としてポアサイズ（濾過精度１μｍ、ポリプロピレン製）を用いた。また、第２軟水化手段１５として、ＮＦ膜（Ａ）（ＮａＣｌ除去率８５〜９５％、ＭｇＳＯ４除去率９９．５％、材質ポリアミド系）を有するスパイラル型ＮＦ膜モジュール（特開２００９−３９６９６号公報に記載のスパイラル型ＲＯ膜モジュールとほぼ同じ構造）を用い、精製手段１６として、ＲＯ膜（ＮａＣｌ除去率９９．５％、材質ポリアミド系）を有するスパイラル型ＲＯ膜モジュール（特開２００９−３９６９６号公報に記載の構造）を用いた。 [Example 1]
Purified water was manufactured using the purified water manufacturing apparatus 1 illustrated in FIG. A water softener (Na-type resin 40L) is used as the first water softening means 12, an activated carbon filter (filtration accuracy 5 μm or less, fibrous activated carbon) is used as the chlorine removal means 13, and a pore size (filtration accuracy 1 μm, polypropylene is used as the check filter 14). Made). Further, as the second water softening means 15, a spiral type NF membrane module having an NF membrane (A) (NaCl removal rate of 85 to 95%, MgSO 4 removal rate of 99.5%, material polyamide type) (JP 2009-39696 A). The spiral RO membrane module having the RO membrane (NaCl removal rate 99.5%, material polyamide type) as the purification means 16 (Japanese Patent Application Laid-Open No. 2009-2009). The structure described in Japanese Patent No. 39696 was used.

処理する原水の水質は、６．２０ｍＳ／ｍであった。原水タンク１１内の原水温度を２４．２℃に調整し、送水ポンプ４１による加圧で原水の圧力を０．２２ＭＰａまで加圧した。チェックフィルタ１４の入口における原水の圧力は０．１８ＭＰａであった。また、送水ポンプ４２により、第２軟水化手段１５の一次側の圧力を０．１８ＭＰａ、運転圧力を０．６８ＭＰａ、その濃縮水側の圧力を０．６８ＭＰａ、二次側の圧力（送水ライン５５のＮＦ水の圧力）を０．２０ＭＰａとし、ＮＦ回収率Ａを９０．２％とした。ここで、ＮＦ回収率Ａ（単位：％）は、下式（Ｉ）で求められる。
Ａ＝（Ｂ−Ｃ）／Ｂ （Ｉ）
前記式（Ｉ）中、Ｂは処理する原水量（Ｌ／時間）、Ｃは第２軟水化手段１５から排水される排水量（Ｌ／時間）である。
なお、第２軟水化手段１５において、ＮＦ膜（Ａ）を透過しなかった濃縮水は、その一部を排水し、残りを濃縮水返送ライン５８を通じて第２軟水化手段１５の一次側に返送した。 The quality of the raw water to be treated was 6.20 mS / m. The raw water temperature in the raw water tank 11 was adjusted to 24.2 ° C., and the pressure of the raw water was increased to 0.22 MPa by pressurization by the water feed pump 41. The pressure of the raw water at the inlet of the check filter 14 was 0.18 MPa. Further, the water supply pump 42 causes the pressure on the primary side of the second water softening means 15 to be 0.18 MPa, the operating pressure to be 0.68 MPa, the pressure on the concentrated water side to be 0.68 MPa, and the pressure on the secondary side (water supply line 55 NF water pressure) was 0.20 MPa, and the NF recovery rate A was 90.2%. Here, the NF recovery rate A (unit:%) is obtained by the following formula (I).
A = (BC) / B (I)
In the formula (I), B is the amount of raw water to be treated (L / hour), and C is the amount of waste water (L / hour) discharged from the second water softening means 15.
The concentrated water that has not permeated the NF membrane (A) in the second water softening means 15 is partially drained and the remainder is returned to the primary side of the second water softening means 15 through the concentrated water return line 58. did.

また、送水ポンプ４３により、精製手段１６の一次側の圧力を０．１６ＭＰａ、運転圧力を０．４３ＭＰａ、その濃縮水側の圧力を０．４３ＭＰａとし、ＲＯ回収率Ｄを８０．３％とした。ここで、ＲＯ回収率Ｄ（単位：％）は、下式（II）で求められる。
Ｄ＝（Ｂ−Ｃ−Ｆ）／（Ｂ−Ｃ） （II）
前記式（II）中、Ｂは処理する原水量（Ｌ／時間）、Ｃは第２軟水化手段１５から排水される排水量（Ｌ／時間）、Ｆは精製手段１６から排水される排水量（Ｌ／時間）である。
なお、精製手段１６のＲＯ膜を透過しなかった濃縮水は、一部を排水し、それ以外を濃縮水返送ライン５９を通じて原水タンク１１に返送した。 Further, the water pump 43 is used to set the primary pressure of the purification means 16 to 0.16 MPa, the operating pressure to 0.43 MPa, the concentrated water pressure to 0.43 MPa, and the RO recovery rate D to 80.3%. . Here, the RO recovery rate D (unit:%) is obtained by the following formula (II).
D = (B-C-F) / (B-C) (II)
In the formula (II), B is the amount of raw water to be treated (L / hour), C is the amount of wastewater drained from the second water softening means 15 (L / hour), and F is the amount of wastewater drained from the purification means 16 (L / Hour).
A part of the concentrated water that did not pass through the RO membrane of the purification means 16 was drained, and the other part was returned to the raw water tank 11 through the concentrated water return line 59.

［例２］
第２軟水化手段１５を、ＮＦ膜（ＮａＣｌ除去率５０〜７０％、ＭｇＳＯ４除去率９８％、材質ポリアミド系）を有するスパイラル型ＮＦ膜モジュールに変更し、精製水製造装置１の運転条件を表１に示すように変更した以外は、例１と同様にして精製水を製造した。 [Example 2]
The second water softening means 15 is changed to a spiral NF membrane module having an NF membrane (NaCl removal rate of 50 to 70%, MgSO 4 removal rate of 98%, material polyamide system), and the operating conditions of the purified water production apparatus 1 are changed. Purified water was produced in the same manner as in Example 1 except that the changes were made as shown in Table 1.

［例３］
第２軟水化手段１５を、ＮＦ膜（ＮａＣｌ除去率６０〜７０％、ＭｇＳＯ４除去率９９％、材質ポリアミド系）を有するスパイラル型ＮＦ膜モジュールに変更し、精製水製造装置１の運転条件を表１に示すように変更した以外は、例１と同様にして精製水を製造した。 [Example 3]
The second water softening means 15 is changed to a spiral type NF membrane module having an NF membrane (NaCl removal rate 60 to 70%, MgSO 4 removal rate 99%, material polyamide system), and the operating conditions of the purified water production apparatus 1 are changed. Purified water was produced in the same manner as in Example 1 except that the changes were made as shown in Table 1.

各例において、第２軟水化手段１５に供給される原水の水質、第２軟水化手段１５におけるＮＦ膜（Ａ）を透過したＮＦ水の水質、及び精製手段１６のＲＯ膜を透過した精製水の水質を測定した結果を表１に示す。
なお、表１中、全体回収率Ｇ（精製水の回収率）は、下式（III）で求められる。
Ｇ＝（Ｂ−Ｃ−Ｆ）／Ｂ （III）
前記式（III）中、Ｂは処理する原水量（Ｌ／時間）、Ｃは第２軟水化手段１５から排水される排水量（Ｌ／時間）、Ｆは精製手段１６から排水される排水量（Ｌ／時間）である。
また、第２軟水化手段１５の供給水は、チェックフィルタ１４から送られてくる原水と、濃縮水返送ライン５８を通じて返送するＮＦ膜を透過しなかった濃縮水とを合わせたものである。 In each example, the quality of raw water supplied to the second water softening means 15, the quality of NF water that has passed through the NF membrane (A) in the second water softening means 15, and purified water that has passed through the RO membrane of the purification means 16. The results of measuring the water quality are shown in Table 1.
In Table 1, the overall recovery rate G (purified water recovery rate) is obtained by the following formula (III).
G = (B-C-F) / B (III)
In the formula (III), B is the amount of raw water to be treated (L / hour), C is the amount of wastewater drained from the second water softening means 15 (L / hour), and F is the amount of wastewater drained from the purification means 16 (L / Hour).
The water supplied from the second water softening means 15 is a combination of the raw water sent from the check filter 14 and the concentrated water that has not passed through the NF membrane returned through the concentrated water return line 58.

Figure 0005582847
Figure 0005582847

表１に示すように、ＮＦ膜（Ａ）を有する第２軟水化手段１５を用いた例１では、得られた精製水の水質が０．１４ｍＳ／ｍと非常に良好であった。また、第２軟水化手段１５のＮＦ膜（Ａ）を透過したＮＦ水の水質も１．０６ｍＳ／ｍと、処理前の原水の水質に比べて良好であるので、精製手段１６のＲＯ膜を透過しなかった濃縮水の水質（５．３８ｍＳ／ｍ）は処理前の原水の水質（６．２０ｍＳ／ｍ）よりも良好である。そのため、ＲＯ膜を透過しなかった濃縮水を原水タンク１１に返送して処理前の原水と混合すれば、原水タンク１１中の原水が希釈されてその水質が向上し、ＲＯ膜にかかる負担を増大させずに、精製水の回収率を向上させることができ、さらに精製水の水質も向上する。
なお、第２軟水化手段１５に供給される供給水の水質が３１．２５ｍＳ／ｍと悪くなっているのは、ＮＦ膜（Ａ）を透過しなかった濃縮水を返送しているためである。 As shown in Table 1, in Example 1 using the second water softening means 15 having the NF membrane (A), the quality of the purified water obtained was very good at 0.14 mS / m. Moreover, since the quality of the NF water that has passed through the NF membrane (A) of the second water softening means 15 is 1.06 mS / m, which is better than the quality of the raw water before treatment, the RO membrane of the purification means 16 is used. The quality of concentrated water that did not permeate (5.38 mS / m) is better than the quality of raw water before treatment (6.20 mS / m). Therefore, if the concentrated water that did not permeate the RO membrane is returned to the raw water tank 11 and mixed with the raw water before treatment, the raw water in the raw water tank 11 is diluted and the quality of the water is improved, and the burden on the RO membrane is increased. Without increasing, the recovery rate of purified water can be improved, and the quality of purified water is also improved.
The reason why the quality of the water supplied to the second water softening means 15 is as poor as 31.25 mS / m is because the concentrated water that has not permeated the NF membrane (A) is returned. .

一方、ＮＦ膜（Ａ）の代わりに、各種イオンの除去率がＮＦ膜（Ａ）よりも低いＮＦ膜を用いた例２及び３では、得られる精製水の水質が０．２６ｍＳ／ｍ、０．２８ｍＳ／ｍと低くなった。また、ＮＦ膜を透過したＮＦ水の水質が５．２２ｍＳ／ｍ、５．２８ｍＳ／ｍと例１に比べて低くなっていることから、精製手段１６においてＲＯ膜を透過しなかった濃縮水の水質は、２６．１０ｍＳ／ｍ、２６．８０ｍＳ／ｍと、処理前の原水の水質よりも著しく低くなっている。そのため、原水タンク１１に返送して処理前の原水に混合する濃縮水が増加するほど、原水タンク１１内の原水の水質が悪くなり、ＲＯ膜にかかる負担が高まってその寿命が短くなるうえ、得られる精製水の水質が低下する。   On the other hand, in Examples 2 and 3 in which the removal rate of various ions is lower than that of the NF membrane (A) instead of the NF membrane (A), the quality of the purified water obtained is 0.26 mS / m, 0 It was as low as .28 mS / m. In addition, since the quality of NF water that has passed through the NF membrane is 5.22 mS / m and 5.28 mS / m, which is lower than that of Example 1, the concentrated water that has not passed through the RO membrane in the purification means 16. The water quality is 26.10 mS / m and 26.80 mS / m, which are significantly lower than the quality of raw water before treatment. Therefore, as the concentrated water returned to the raw water tank 11 and mixed with the raw water before treatment increases, the quality of the raw water in the raw water tank 11 becomes worse, the burden on the RO membrane increases, and its life is shortened. The quality of the purified water obtained is lowered.

本発明の精製水製造装置はエンドトキシン、生菌などの除去に優れている。製造される精製水は、特に人工透析に好適に利用でき、また他部門でも活用可能である。   The purified water production apparatus of the present invention is excellent in removing endotoxins and viable bacteria. The purified water produced can be suitably used particularly for artificial dialysis, and can also be used in other departments.

１ 精製水製造装置 １１ 原水タンク １２ 第１軟水化手段 １３ 塩素除去手段 １４ チェックフィルタ １５ 第２軟水化手段 １６ 精製手段 １７ 精製水タンク ５９ 濃縮水返送ライン   DESCRIPTION OF SYMBOLS 1 Purified water production apparatus 11 Raw water tank 12 1st water softening means 13 Chlorine removal means 14 Check filter 15 2nd water softening means 16 Purification means 17 Purified water tank 59 Concentrated water return line

Claims (3)

原水をイオン交換樹脂によって軟水化する第１軟水化手段と、
前記第１軟水化手段により軟水化された原水を活性炭で濾過して残留塩素を除去する塩素除去手段と、
残留塩素が除去された原水を下記ナノ濾過膜で濾過して軟水化する第２軟水化手段と、
前記第２軟水化手段により軟水化された原水を逆浸透膜で濾過して精製水を得る精製手段と、
前記逆浸透膜を透過しなかった濃縮水を、前記第２軟水化手段の一次側の原水と混合する濃縮水返送ラインと、
を有していることを特徴とする精製水製造装置。
（ナノ濾過膜）
濃度２０００ｍｇ／ＬのＮａＣｌ水溶液を、運転圧力０．５ＭＰａ、温度２５℃、ｐＨ６．５〜７．０、膜透過水の回収率１５％の条件で３０分間濾過したときのＮａＣｌの除去率が７５〜９５％であるナノ濾過膜。 First water softening means for softening raw water with an ion exchange resin;
Chlorine removing means for filtering the raw water softened by the first water softening means with activated carbon to remove residual chlorine;
A second water softening means for softening the raw water from which residual chlorine has been removed by filtration through the following nanofiltration membrane;
Purification means for obtaining purified water by filtering the raw water softened by the second water softening means through a reverse osmosis membrane;
A concentrated water return line for mixing the concentrated water that has not passed through the reverse osmosis membrane with the raw water on the primary side of the second water softening means;
The purified water manufacturing apparatus characterized by having.
(Nanofiltration membrane)
When the NaCl aqueous solution having a concentration of 2000 mg / L is filtered for 30 minutes under the conditions of an operating pressure of 0.5 MPa, a temperature of 25 ° C., a pH of 6.5 to 7.0, and a recovery rate of membrane permeated water of 15%, the NaCl removal rate is 75. Nanofiltration membrane that is ~ 95%. 前記ナノ濾過膜が、濃度２０００ｍｇ／ＬのＭｇＳＯ４水溶液を、運転圧力０．５ＭＰａ、温度２５℃、ｐＨ６．５〜７．０、膜透過水の回収率１５％の条件で３０分間濾過したときのＭｇＳＯ４の除去率が９９．５％以上のナノ濾過膜である、請求項１に記載の精製水製造装置。 When the nanofiltration membrane filtered an aqueous MgSO 4 solution having a concentration of 2000 mg / L for 30 minutes under the conditions of an operating pressure of 0.5 MPa, a temperature of 25 ° C., a pH of 6.5 to 7.0, and a recovery rate of membrane permeated water of 15%. removal rate of MgSO 4 of a nanofiltration membrane or 99.5%, purified water manufacturing apparatus according to claim 1. 前記濃縮水返送ラインにより前記濃縮水の９０％以上が原水と混合される、請求項１または２に記載の精製水製造装置。   The purified water production apparatus according to claim 1 or 2, wherein 90% or more of the concentrated water is mixed with raw water by the concentrated water return line.
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