JP2016022448A - Water treatment apparatus and method for washing water treatment facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment apparatus and a method for washing a water treatment facility that can reduce a chemical solution usage amount and a washing waste solution disposal amount and suppress washing costs.SOLUTION: A water treatment apparatus includes n units (n is an integer of 3 or more) of water treatment facilities 12, 14, 16, and 18 that are connected in series for sequentially conducting treated water, and m units (m is any integer of 2 to n) among the n units of water treatment facilities which are facilities to be washed. First to m-th washing solution tanks 22, 26, and 28 are disposed corresponding to the first to m-th facilities 12, 16, and 18 to be washed. The water treatment apparatus includes: first to m-th recycling washing means for circulating and passing a washing solution in a k-th (k is an integer of 1 to m) washing solution tank in a forward washing direction to a k-th facility to be washed; and solution feeding means for feeding the washing solution in any one washing solution tank among the first to m-th washing solution tanks to another washing solution tank.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water treatment apparatus and a water treatment facility cleaning method.

  Currently, desalination and drainage recovery of seawater and brine using a reverse osmosis membrane (Reverse Osmosis Membrane: RO membrane) system is performed. Since the RO membrane is contaminated with the use and the performance of the RO membrane is deteriorated, the RO membrane is regularly cleaned with chemicals. Usually, the cleaning effluent used to clean the RO membrane is discarded.

  However, when the raw water is extremely contaminated and the frequency of chemical cleaning of the RO membrane is high, the cost of the chemical becomes high. Therefore, pretreatment is performed using a filter or a membrane filtration device to remove the contaminants in the RO membrane in advance. However, a certain amount of chemical cleaning is often required for filter membranes for pretreatment, membrane filtration devices such as microfiltration (MF) membranes and ultrafiltration (UF) membranes. Cost was a big problem.

  Patent Document 1 describes the use of reverse osmosis membrane cleaning wastewater for cleaning turbidity equipment as a technique for reducing the cleaning cost when cleaning a filtration medium. However, the method of Patent Document 1 is for cleaning the turbidity membrane in a different process using the chemical solution waste water of the reverse osmosis membrane, and is not used for cleaning the pretreatment device, It is not envisaged to clean pretreatment equipment consisting of multiple unit operations.

  Thus, conventionally, when raw water with a high pollution load is treated with an RO membrane, there has been a problem that the cost of chemical cleaning of the RO membrane is increased. In particular, when pretreatment equipment and RO membranes are combined, chemical cleaning is performed in a plurality of unit operations, so the degree of contamination of each equipment is not uniform, and waste such as discarding cleaning liquid that is not very dirty is wasted. As a result, there is a problem that a large amount of chemical solution is used and a waste amount of cleaning waste liquid is disposed, resulting in an increase in cleaning cost.

JP 2011-104504 A

  The present invention has been made in view of the above circumstances, and provides a water treatment apparatus and a water treatment equipment washing method that can reduce the amount of chemical solution used and the amount of waste waste water for washing and reduce the washing cost. Is an issue.

  The water treatment apparatus of the present invention (first invention) is provided corresponding to each water treatment facility and a plurality of water treatment facilities connected in series so that the water to be treated is sequentially passed. A plurality of cleaning liquid tanks for storing cleaning liquid for cleaning the processing equipment, and two or more of the plurality of cleaning liquid tanks are connected to each other, and in the connected cleaning liquid tank, the cleaning liquid in one cleaning liquid tank is another It is characterized by being sent to the cleaning liquid tank.

  In the first invention, it is preferable that the cleaning liquid is fed from the upstream side and / or the downstream side to the at least one of the plurality of water treatment facilities from the cleaning liquid tank.

  In the first invention, a water treatment facility not provided with a corresponding cleaning liquid tank is further provided, and at least any one of the plurality of cleaning liquid tanks is provided for the water treatment facility not provided with the corresponding cleaning liquid tank. The cleaning liquid in the tank may be sent.

  In the first invention, a water treatment facility that does not perform cleaning is further provided, and a pipe for supplying the cleaning solution from one cleaning solution tank to another cleaning solution tank is provided so as to bypass the water treatment facility that is not cleaned. May be.

  The water treatment apparatus of the present invention (second invention) is a water treatment apparatus having n (n is an integer of 3 or more) water treatment facilities connected in series so that the water to be treated is sequentially passed. Of the n water treatment facilities, m (m is an integer from 2 to n) are to-be-cleaned facilities, and the first to m-th cleaning liquids correspond to the first to m-th to-be-cleaned facilities. A tank is installed, and the first to m-th circulating washings for circulating the washing liquid in the k-th washing liquid tank (k is an integer of 1 to m) through the k-th equipment to be washed in the forward washing direction. And a liquid feeding means for feeding the cleaning liquid in any one of the first to m-th cleaning liquid tanks to another cleaning liquid tank.

  In the second invention, the jth (j is an integer from 1 to (n-1)) water treatment facility and the (j + 1) th water treatment facility are connected, and the treated water of the jth water treatment facility is First to (n-1) connecting pipes to be introduced into the (j + 1) th water treatment facility, and first to (n-1) main branch pipes branching from each connecting pipe, The i-th (i is an integer from 2 to (n-1)) water treatment equipment is the equipment to be cleaned, and the (i-1) main branch pipe corresponds to the equipment to be cleaned by a sub-branch pipe. The i-th main branch pipe is connected to the cleaning liquid tank by a sub-branch pipe, and the cleaning liquid in the cleaning liquid tank is connected to the sub-branch pipe and the (i -1) through the main branch pipe and the (i-1) connecting pipe to the primary side of the equipment to be cleaned, It is preferred to be circulated in the washing liquid tank via the main branch pipe and sub branch pipe of said i.

  In the second aspect of the invention, the frequency of cleaning of the equipment to be cleaned corresponding to the cleaning liquid tank that is the liquid supply source of the cleaning liquid by the liquid supply means is higher than the frequency of cleaning of the equipment to be cleaned corresponding to the cleaning liquid tank that is the liquid destination. The liquid means uses the cleaning liquid in the p-th (p is an integer from 1 to (m-1)) cleaning liquid in the rear stage (r is at least one integer from (p + 1) to m). The liquid is fed to the tank, and the cleaning frequency of the p-th equipment to be cleaned is preferably higher than the cleaning frequency of the r-th equipment to be cleaned.

  The water treatment device of the present invention (third invention) is a water treatment device having n (n is an integer of 3 or more) water treatment equipment connected in series so that the water to be treated is sequentially passed. Of the n water treatment facilities, m (m is an integer from 2 to n) are facilities to be cleaned, and first to m-th cleaning liquid tanks are installed corresponding to the first to m-th to-be-cleaned facilities. The first to the (th) thru (s) for circulating the cleaning liquid in the s-th cleaning liquid tank in the back-washing direction with respect to the s-th (s is an integer of 1 to (m-1)) equipment to be cleaned. m-1), and a liquid feeding means for feeding the cleaning liquid in the preceding or subsequent cleaning liquid tank to the s-th cleaning liquid tank. To do.

  In the third aspect of the invention, the jth (j is an integer from 1 to (n-1)) water treatment facility and the (j + 1) th water treatment facility are connected, and the treated water of the jth water treatment facility is First to (n-1) connecting pipes to be introduced into the (j + 1) th water treatment facility, and first to (n-1) main branch pipes branching from each connecting pipe, The i-th (i is an integer from 2 to (n-1)) water treatment facility is a facility to be cleaned, and the (i-1) main branch pipe is the (i-1) sub-branch pipe. Is connected to the cleaning liquid tank corresponding to the equipment to be cleaned, the i-th main branch pipe is connected to the cleaning liquid tank by a sub-branch pipe, and the cleaning liquid in the cleaning liquid tank is It is supplied to the secondary side of the equipment to be cleaned through the branch pipe, the i-th main branch pipe and the i-th connection pipe, and the cleaning drainage of the equipment to be cleaned is connected to the (i-1) -th contact. Pipe, said (i-1) of the preferred to be circulated in the washing liquid tank via the sub branch of the main branch pipe and said (i-1).

  In the third aspect of the invention, the i-th main branch pipe is connected to the rear-stage side cleaning liquid tank by the i-th sub-branch pipe, and before the circulating backwashing of the equipment to be cleaned, , And supplied to the secondary side of the equipment to be cleaned via the i-th sub-branch pipe, the i-th main branch pipe and the i-th connection pipe, It is introduced into the cleaning liquid tank corresponding to the equipment to be cleaned through the connection pipe of (i-1), the (i-1) main branch pipe and the (i-1) sub branch pipe. preferable.

  In the present invention, the first to m-th cleaning equipment is a filter, a microfiltration membrane device, an ultrafiltration membrane device, a reverse osmosis membrane device, or an ultraviolet irradiation device, and the water treatment equipment that is not the cleaning equipment is A treatment water tank, a biological treatment tank, a biological activated carbon tower, a pump, a decarbonation tower, or a degassing membrane device is preferable.

  In the present invention, a high-order water treatment facility into which treated water of the n-th water treatment facility is introduced may be further provided downstream of the n-th water treatment facility.

  The water treatment facility cleaning method of the present invention (the fourth invention) is a cleaning method for cleaning at least a part of the water treatment facility of the water treatment apparatus according to the second invention, wherein a cleaning liquid is circulated in a forward direction between the cleaning liquid tanks of k and the kth equipment to be cleaned is cleaned, and after the circulating cleaning of the kth equipment to be cleaned, The cleaning liquid is sent to another cleaning liquid tank, and is used as a cleaning liquid for a filtration device corresponding to the cleaning liquid tank.

  The water treatment facility cleaning method of the present invention (the fifth invention) is a cleaning method for cleaning at least a part of the water treatment facility of the water treatment apparatus according to the third invention, and is for the sth cleaning liquid tank. The step of feeding the cleaning liquid in the cleaning liquid tank on the rear stage side, and circulating the cleaning liquid in the backwash direction between the s-th cleaning equipment and the s-th cleaning liquid tank, thereby providing the s-th cleaning equipment And a step of cleaning.

  According to the present invention, since the washing drainage of one water treatment facility is reused for the forward washing or backwashing of another water treatment facility, the amount of chemical solution used and the amount of waste cleaning wastewater are reduced, and the cost and waste of the chemical solution are reduced. The burden of the liquid treatment can be reduced and the cleaning cost can be reduced.

It is the schematic of the water treatment apparatus which concerns on embodiment of this invention. It is a figure explaining the circulation washing process of RO membrane unit. It is a figure explaining the circulation washing process of a security filter. It is a figure explaining the circulation washing process of a UF membrane unit. It is a figure explaining the backwash process of a security filter. It is a figure explaining the backwash process of a UF membrane unit. It is a figure explaining the circulation backwash process of a safety filter. It is a figure explaining the circulation backwash process of a UF membrane unit. It is a figure explaining the circulation backwash process of a UF membrane unit. It is a figure explaining the circulation backwash process of a UF membrane unit. It is a figure explaining the backwash process of a security filter. It is a figure explaining the backwash process of a UF membrane unit. It is the schematic of the water treatment apparatus by a modification. It is the schematic of the water treatment apparatus by a modification.

  Hereinafter, embodiments of the present invention will be described in detail.

  A water treatment apparatus according to an embodiment of the present invention includes a plurality of water treatment facilities connected in series so that raw water (treated water) is sequentially passed, and a water treatment facility (treated) that performs cleaning with a chemical solution. And a plurality of cleaning liquid tanks installed corresponding to the cleaning equipment). As an example of the water treatment apparatus, FIG. 1 is a filtration apparatus in which four stages of water treatment equipment connected in series are provided, and three of the four stages perform cleaning with a chemical solution. The thing provided with three washing | cleaning liquid tanks is shown. As shown in FIG. 1, the water treatment device includes a UF membrane unit 12 that is a first water treatment facility (first filtration device), an auxiliary facility 14 that is a second water treatment facility, and a third water treatment facility (second filtration device). Cleaning filter corresponding to the safety filter 16, the RO membrane unit 18 serving as the fourth water treatment facility (third filtration device), the cleaning liquid tank 22 (first cleaning liquid tank) corresponding to the UF membrane unit 12, and the cleaning liquid corresponding to the safety filter 16. A tank 26 (second cleaning liquid tank) and a cleaning liquid tank 28 (third cleaning liquid tank) corresponding to the RO membrane unit 18 are provided.

  The second water treatment facility is a water treatment facility that does not perform or cannot be washed with a chemical solution. In the present embodiment, the second water treatment facility is described as an auxiliary facility 14 including a UF treatment water tank and a supply pump. Here, the water treatment equipment that does not or cannot be washed with a chemical solution is, for example, a treated water tank, a pump, a biological treatment tank, a biological activated carbon tower, a decarbonation tower, a degassing membrane device, or the like. The membrane filtration device or the filter may be a water treatment facility that does not perform cleaning with a chemical solution. In addition, the said water treatment facility is an illustration and is not limited to these. For example, the ultraviolet irradiation apparatus described later may cause the glass surface to become cloudy depending on the concentration of the alkaline cleaning liquid, so that the cleaning may be avoided, or the treatment water tank or pump may be cleaned because it becomes a hotbed of slime.

  A raw water pipe 40 is connected to the primary side of the UF membrane unit 12, and brackish water, seawater, ground water, landfill leachate, organic matter containing solutes such as ions and salts from a raw water tank (not shown) through the raw water pipe 40. Raw water such as waste water and biological wastewater is supplied. The UF membrane unit 12 has an ultrafiltration membrane (UF membrane), and filters raw water to obtain UF treated water and concentrated water. The shape of the UF membrane is not particularly limited.

  The secondary side of the UF membrane unit 12 and the UF treatment water tank of the auxiliary equipment 14 are connected by a connection pipe 41 (first connection pipe), and the UF treatment water that has passed through the UF membrane unit 12 passes through the connection pipe 41. It is introduced into the UF treated water tank. On the other hand, the concentrated water is discharged through the pipe 45. Branch pipes 46 and 47 branch from the pipe 45, and the concentrated water is returned to the raw water tank through the branch pipe 46. The branch pipe 47 is connected to a sub branch pipe 61 described later.

  The supply pump of the incidental equipment 14 and the primary side of the safety filter 16 are connected by a connection pipe 42 (second connection pipe), and the UF treated water stored in the UF treated water tank is connected via the connection pipe 42 by the supply pump. Are introduced into the security filter 16.

  The secondary side of the safety filter 16 and the primary side of the RO membrane unit 18 are connected by a connection pipe 43 (third connection pipe), and treated water from which foreign matter has been removed by the safety filter 16 is passed through the connection pipe 43. It is introduced into the RO membrane unit 18.

  The RO membrane unit 18 has a reverse osmosis membrane (RO membrane) and performs a filtration treatment to obtain treated water and concentrated water. The shape of the RO membrane is not particularly limited. A treated water extraction pipe 44 is connected to the secondary side of the RO membrane unit 18, and the treated water that has passed through the RO membrane unit 18 is discharged through the treated water extraction pipe 44. On the other hand, the concentrated water is returned to the raw water tank via the pipe 48. A branch pipe 49 branches from the pipe 48, and the branch pipe 49 is connected to the cleaning liquid tank 28.

  As described above, in the water treatment apparatus shown in FIG. 1, raw water is sequentially passed through the UF membrane unit 12, the auxiliary equipment 14, the security filter 16, and the RO membrane unit 18 to be treated.

  In the cleaning liquid tank 22, a cleaning liquid for circulating and cleaning the UF membrane of the UF membrane unit 12 is stored. Similarly, the cleaning liquid tank 26 stores cleaning liquid for circulating and cleaning the safety filter 16. The cleaning liquid tank 28 stores cleaning liquid for circulating and cleaning the RO membrane of the RO membrane unit 18.

  As shown in FIG. 1, leading branch pipes 90 and 92 are branched from the raw water pipe 40, and the leading branch pipes 90 and 92 connect the raw water pipe 40 and the cleaning liquid tank 22. The leading branch pipe 90 is a through pipe without a pump. On the other hand, the leading branch pipe 92 is a pipe with a pump provided with a pump 32.

  A main branch pipe 51 (first main branch pipe) branches from the connection pipe 41, and a sub branch pipe 61 and a connecting pipe 65 branch from the main branch pipe 51. The sub branch pipe 61 connects the main branch pipe 51 and the cleaning liquid tank 22. The connecting pipe 65 connects the main branch pipe 51 and a main branch pipe 52 described later.

  A main branch pipe 52 (second main branch pipe) branches from the connection pipe 42, and a sub branch pipe 72 and the above-described connecting pipe 65 branch from the main branch pipe 52. The sub branch pipe 72 connects the main branch pipe 52 and the cleaning liquid tank 26. Further, a sub branch pipe 82 provided with a pump 36 is provided in parallel with the sub branch pipe 72, and the main branch pipe 52 and the cleaning liquid tank 26 are also connected by the sub branch pipe 82.

  A main branch pipe 53 (third main branch pipe) branches from the connection pipe 43, and a sub branch pipe 63 and a sub branch pipe 83 branch from the main branch pipe 53. The sub branch pipe 63 connects the main branch pipe 53 and the cleaning liquid tank 26. The sub branch pipe 83 connects the main branch pipe 53 and the cleaning liquid tank 28 and is provided with a pump 38.

  A tail branch pipe 94 branches from the treated water outlet pipe 44, and the tail branch pipe 94 connects the treated water outlet pipe 44 and the cleaning liquid tank 28.

  A cleaning liquid for circulating and cleaning the RO membrane of the RO membrane unit 18 is stored in the cleaning liquid tank 28. This cleaning liquid is a mixture of the treated water of the RO membrane unit 18 supplied via the treated water extraction pipe 44 and the tail branch pipe 94 and the chemical added by the chemical addition means 96. As the chemical, alkali agents such as sodium hydroxide and potassium hydroxide, chelating agents such as nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and gluconic acid can be used. However, other cleaning chemicals may be used as the cleaning chemicals, and known cleaning chemicals such as acids, hypochlorites, and bonded chlorine may be used. One cleaning chemical may be used alone, or two or more cleaning chemicals may be mixed and used.

  The RO membrane circulation cleaning process of the RO membrane unit 18 will be described with reference to FIG. In FIG. 2, the flow of the cleaning liquid is indicated by a bold line. The pump 38 supplies the cleaning liquid stored in the cleaning liquid tank 28 to the primary side of the RO membrane unit 18 through the secondary branch pipe 83, the main branch pipe 53, and the connection pipe 43, and performs chemical cleaning of the RO membrane. The cleaning drainage discharged from the processing water outlet of the RO membrane unit 18 is introduced into the cleaning liquid tank 28 via the processing water extraction pipe 44 and the tail branch pipe 94. In addition, the cleaning waste liquid discharged from the concentrated water outlet of the RO membrane unit 18 is introduced into the cleaning liquid tank 28 through the pipe 48 and the branch pipe 49. In this manner, the cleaning liquid is circulated in the forward direction between the cleaning liquid tank 28 and the RO membrane unit 18.

  Since the cleaning solution used for cleaning the RO membrane gradually decreases its cleaning effect, it is periodically replaced with a new one. When the cleaning liquid is replaced with a new one, the cleaning waste liquid in the cleaning liquid tank 28 is not discarded but sent to the cleaning liquid tanks 22 and 26 via the pipe 98 by the pump 30. The amount of liquid supplied to the cleaning liquid tanks 22 and 26 by the pump 30 may be equal, or may be supplied only to one of the cleaning liquid tanks. When all or most of the cleaning liquid in the cleaning liquid tank 28 is sent to the cleaning liquid tanks 22 and 26, the treated water of the RO membrane unit 18 is supplied to the cleaning liquid tank 28. At this time, a chemical is added from the chemical addition means 96. As a result, the RO membrane cleaning liquid is replaced with a new one.

  A cleaning liquid for circulating and cleaning the safety filter 16 is stored in the cleaning liquid tank 26. This cleaning liquid is the cleaning liquid (RO membrane cleaning drainage) sent from the cleaning liquid tank 28 by the pump 30. However, in order to adjust the concentration, etc., it can be mixed with the treated water of the safety filter 16 supplied via the connection pipe 43, the main branch pipe 53 and the sub branch pipe 63, or a chemical can be added. Instead of the treated water of the safety filter 16, the treated water of the UF membrane unit 12 may be mixed. Moreover, when the second water treatment facility is an ultraviolet irradiation device or the like, the treated water of the second water treatment facility may be mixed.

  The circulation cleaning process of the safety filter 16 will be described with reference to FIG. In FIG. 3, the flow of the cleaning liquid is indicated by a bold line. The pump 36 supplies the cleaning liquid stored in the cleaning liquid tank 26 to the primary side of the safety filter 16 through the secondary branch pipe 82, the main branch pipe 52, and the connection pipe 42, and performs chemical cleaning of the safety filter 16. The cleaning drainage liquid of the safety filter 16 is introduced into the cleaning liquid tank 26 through the connection pipe 43, the main branch pipe 53 and the sub branch pipe 63. Thus, the cleaning liquid is circulated in the forward direction between the cleaning liquid tank 26 and the safety filter 16.

  The cleaning liquid tank 22 stores cleaning liquid for circulating and cleaning the UF membrane of the UF membrane unit 12. This cleaning liquid is the cleaning liquid (RO membrane cleaning drainage) sent from the cleaning liquid tank 28 by the pump 30. However, it is possible to mix with the treated water of the UF membrane unit 12 supplied through the connection pipe 41, the main branch pipe 51, and the sub branch pipe 61, or to add chemicals for concentration adjustment and the like. Moreover, you may mix with the concentrated water of UF membrane unit 12 instead of the treated water of UF membrane unit 12, and may mix with raw | natural water.

  The UF membrane circulation cleaning process of the UF membrane unit 12 will be described with reference to FIG. In FIG. 4, the flow of the cleaning liquid is indicated by a bold line. The pump 32 supplies the cleaning liquid stored in the cleaning liquid tank 22 to the primary side of the UF membrane unit 12 via the leading branch pipe 92 and the raw water pipe 40 to perform chemical cleaning of the UF membrane. The cleaning liquid discharged from the treated water outlet of the UF membrane unit 12 is supplied to the cleaning liquid tank 22 through the connection pipe 41, the main branch pipe 51 and the sub branch pipe 61. Further, the cleaning drainage discharged from the concentrated water outlet of the UF membrane unit 12 is supplied to the cleaning liquid tank 22 through the pipe 45, the branch pipe 47 and the sub branch pipe 61. Thus, the cleaning liquid is circulated in the forward direction between the cleaning liquid tank 22 and the UF membrane unit 12.

  In the water treatment apparatus shown in FIG. 1, the UF membrane unit 12 and the security filter 16 can be backwashed as well as forward washed. At the time of backwashing, the cleaning liquid in the cleaning liquid tank corresponding to the water treatment equipment on the rear stage side is used for back washing of the water treatment equipment on the front stage side. This is because the cleanliness of the washing waste liquid of the rear side equipment is at a level that can be used for back washing of the front side equipment.

  For example, as shown in FIG. 5, the pump 38 supplies the cleaning liquid stored in the cleaning liquid tank 28 to the secondary side of the security filter 16 through the secondary branch pipe 83, the main branch pipe 53, and the connection pipe 43. Then, the safety filter 16 is back-washed. Cleaning drainage accompanying backwashing of the safety filter 16 is introduced into the cleaning liquid tank 26 via the connection pipe 42, the main branch pipe 52 and the sub branch pipe 72. In this way, the cleaning liquid in the cleaning liquid tank 28 passes through the safety filter 16 in the backwash direction and flows into the cleaning liquid tank 26.

  In addition, as shown in FIG. 6, the pump 36 allows the cleaning liquid stored in the cleaning liquid tank 26 to pass through the secondary branch pipe 82, the connecting pipe 65, the main branch pipe 51, and the connection pipe 41. The UF membrane unit 12 is backwashed by supplying to the next side. The cleaning waste liquid accompanying backwashing of the UF membrane unit 12 is introduced into the cleaning liquid tank 22 through the raw water pipe 40 and the leading branch pipe 90. In this way, the cleaning liquid in the cleaning liquid tank 26 passes through the UF membrane unit 12 in the backwash direction and flows into the cleaning liquid tank 22. By providing the connecting pipe 65 that connects the secondary branch pipe 82 and the main branch pipe 51, the cleaning liquid from the cleaning liquid tank 26 is supplied to the secondary side of the UF membrane unit 12, bypassing the incidental equipment 14. can do.

  The main branch pipe branching from the connecting pipe connecting two adjacent water treatment facilities is divided into the order of backwashing the water treatment facility on the upstream side (upstream side) of the branch point and the water treatment facility on the downstream side (downstream side). By using it for washing, the entire connection pipe can be washed.

  For example, as shown in FIGS. 2 and 5, a cleaning liquid tank fed by a pump 38 to one main branch pipe 53 branched from a connection pipe 43 that connects the safety filter 16 and the RO membrane unit 18. The cleaning liquid in the flow 28 flows, and this cleaning liquid can be used for the forward circulation cleaning of the RO membrane and the back cleaning of the safety filter 16. The entire connection pipe 43 can be cleaned by circulating cleaning of the RO membrane and back cleaning of the safety filter 16.

  In addition, although illustration is abbreviate | omitted, each piping is provided with the flow-path switching valve, the cutoff valve, etc., By controlling these valves, water treatment and washing | cleaning processing as mentioned above can be performed now. Yes.

  According to this embodiment, since the RO membrane cleaning effluent is reused for cleaning the water treatment equipment in the previous stage, compared with the case where the RO membrane cleaning effluent is discarded, By reducing the amount of washing waste liquid discarded, the chemical cost and the burden of waste liquid treatment can be reduced, and the washing cost can be suppressed.

  For the reverse cleaning of the water treatment facility, the cleaning liquid in the cleaning liquid tank corresponding to the own equipment may be used instead of the cleaning liquid in the cleaning liquid tank corresponding to the subsequent water treatment equipment. For example, as shown in FIG. 7, a connecting pipe 66 that connects the sub-branch pipe 82 and the sub-branching pipe 63 is provided, and the pump 36 supplies the cleaning liquid stored in the cleaning liquid tank 26 to the sub-branching pipe 82 and the connecting pipe. 66, the secondary branch pipe 63, the main branch pipe 53, and the connection pipe 43 are supplied to the secondary side of the safety filter 16 to backwash the safety filter 16. Cleaning drainage accompanying backwashing of the safety filter 16 is introduced into the cleaning liquid tank 26 via the connection pipe 42, the main branch pipe 52 and the sub branch pipe 72. In this way, the circulating back cleaning process of the safety filter 16 is performed using the cleaning liquid in the cleaning liquid tank 26.

  Further, as shown in FIG. 8, a connecting pipe 67 that connects the leading branch pipe 92 and the main branch pipe 51 is provided, and the pump 32 supplies the cleaning liquid stored in the cleaning liquid tank 22 to the leading branch pipe 92 and the connecting pipe. 67, supplying to the secondary side of the UF membrane unit 12 through the main branch pipe 51 and the connection pipe 41, and the UF membrane unit 12 is backwashed. The primary side of the UF membrane unit 12 is closed by a valve, and the cleaning drainage liquid accompanying backwashing of the UF membrane unit 12 is discharged from the concentrated water outlet of the UF membrane unit 12, and the pipe 45, the branch pipe 47, and the sub branch It is introduced into the cleaning liquid tank 22 through the pipe 61. In this way, the circulating back cleaning process of the UF membrane unit 12 is performed using the cleaning liquid in the cleaning liquid tank 22.

  For the circulating back cleaning process of the UF membrane unit 12 using the cleaning liquid in the cleaning liquid tank 22, as shown in FIG. 9, a connecting pipe 68 for connecting the leading branch pipe 92 and the connecting pipe 41 is provided, and the pump 32 is connected to the cleaning liquid. The cleaning liquid stored in the tank 22 is supplied to the secondary side of the UF membrane unit 12 through the leading branch pipe 92, the connecting pipe 68, and the connection pipe 41 so that the UF membrane unit 12 is back-washed. Good. The primary side of the UF membrane unit 12 is closed by a valve, and the cleaning drainage liquid accompanying backwashing of the UF membrane unit 12 is discharged from the concentrated water outlet of the UF membrane unit 12, and the pipe 45, the branch pipe 47, and the sub branch It is introduced into the cleaning liquid tank 22 through the pipe 61.

  Further, as shown in FIG. 10, a pipe 69 for connecting the pipe 45 and the cleaning liquid tank 22 is provided, and a pump 33 is provided in the sub branch pipe 61, and the pump 33 stores the cleaning liquid stored in the cleaning liquid tank 22. The UF membrane unit 12 may be backwashed by supplying it to the secondary side of the UF membrane unit 12 via the sub branch pipe 61, the main branch pipe 51 and the connection pipe 41. The primary side of the UF membrane unit 12 is closed by a valve, and the washing drainage liquid accompanying backwashing of the UF membrane unit 12 is discharged from the concentrated water outlet of the UF membrane unit 12 and is passed through the pipe 45 and the pipe 69. It is introduced into the tank 22.

  After the filter device is back-washed using the cleaning liquid in the cleaning liquid tank corresponding to the latter-stage filter device, the cleaning solution may be circulated to continue the back-washing process. For example, as shown in FIG. 11, a connecting pipe 66 that connects the secondary branch pipe 82 and the secondary branch pipe 63 is provided, and the pump 38 removes the cleaning liquid stored in the cleaning liquid tank 28 from the secondary branch pipe 83 and the main branch. Supplying to the secondary side of the safety filter 16 through the pipe 53 and the connecting pipe 43, the safety filter 16 is backwashed. Cleaning drainage accompanying backwashing of the safety filter 16 is introduced into the cleaning liquid tank 26 via the connection pipe 42, the main branch pipe 52 and the sub branch pipe 72. This back washing process is performed for a predetermined time, and when a predetermined amount of cleaning liquid is stored in the cleaning liquid tank 26, the pump 38 is stopped and the pump 36 is operated, and the pump 36 is stored in the cleaning liquid tank 26 as in FIG. The cleaning liquid is supplied to the secondary side of the safety filter 16 through the secondary branch pipe 82, the connecting pipe 66, the sub branch pipe 63, the main branch pipe 53, and the connection pipe 43, and the safety filter 16 is backwashed.

  The stop of the pump 38 and the operation of the pump 36 may be performed simultaneously, or the stop of the pump 38 may be earlier. When the pump 38 is stopped more slowly, the discharge pressures of the pump 36 and the pump 38 are adjusted so that the cleaning liquid fed by the pump 36 flows into the main branch pipe 53. Further, a pump is provided in the connecting pipe 66, and when the safety filter 16 is circulated and backwashed, the cleaning drainage accompanying the backwashing of the safety filter 16 is connected to the connection pipe 42, the main branch pipe 52, the sub branch pipe 82, and the connection. The cleaning liquid may be supplied to the secondary side of the safety filter 16 through the pipe 66, the sub branch pipe 63, the main branch pipe 53, and the connection pipe 43 so that the cleaning liquid circulates without passing through the cleaning liquid tank 26.

  Similarly, the connecting pipe 67, the connecting pipe 68, or the pump 33 shown in FIG. 8, FIG. 9, or FIG. 10 is provided, and the UF membrane unit 12 shown in FIG. After the fixed amount storage, the pump 36 may be stopped, and the circulation back washing process of the UF membrane unit 12 shown in FIG. 8, FIG. 9 or FIG. 10 may be performed. Further, as shown in FIG. 12, before the circulating back washing process of the UF membrane unit 12, the pump 38 supplies the cleaning liquid stored in the cleaning liquid tank 28 to the sub branch pipe 83, the sub branch pipe 63, and the connecting pipe 66. The UF membrane unit 12 may be back-washed by supplying it to the secondary side of the UF membrane unit 12 through the secondary branch pipe 82, the connecting pipe 65, the main branch pipe 51, and the connection pipe 41. By providing the connecting pipes 65 and 66, the cleaning liquid from the cleaning liquid tank 28 can be supplied to the secondary side of the UF membrane unit 12, bypassing the safety filter 16 and the incidental equipment 14. The cleaning waste liquid accompanying backwashing of the UF membrane unit 12 is introduced into the cleaning liquid tank 22 through the raw water pipe 40 and the leading branch pipe 90.

  As described above, when the cleaning liquid in the subsequent cleaning liquid tank is sent to the preceding cleaning liquid tank, not only the cleaning liquid is directly sent from the subsequent cleaning liquid tank to the preceding cleaning liquid tank via the pipe 98 but also the front side. The liquid can also be fed while backwashing the filtration device.

  The water treatment facility on the front side has a higher washing frequency due to the higher turbidity of the raw water (treated water), and the turbidity of the washing drainage may be lower than the water treatment facility on the rear side. In that case, the washing drainage liquid of the preceding water treatment facility can be reused for washing the subsequent water treatment facility. For example, when the cleaning frequency of the UF membrane unit 12 is higher than the cleaning frequency of the safety filter 16 and the RO membrane unit 18, as shown in FIG. A pump 31 for feeding liquid to the tanks 26 and 28 is provided. A cleaning liquid for circulating and cleaning the UF membrane of the UF membrane unit 12 is stored in the cleaning liquid tank 22 serving as a liquid supply source. This cleaning liquid is a mixture of the treated water of the UF membrane unit 12 supplied via the connection pipe 41, the main branch pipe 51 and the sub branch pipe 61 and the chemical added by the chemical addition means 97.

  Since the cleaning effect used for cleaning the UF membrane gradually deteriorates, it is periodically replaced with a new one. When the cleaning liquid is replaced with a new one, the cleaning drainage liquid in the cleaning liquid tank 22 is not discarded but sent to the cleaning liquid tanks 26 and 28 via the pipe 98 by the pump 31. When all or most of the cleaning liquid in the cleaning liquid tank 22 is sent to the cleaning liquid tanks 26 and 28, the treated water of the UF membrane unit 12 is supplied to the cleaning liquid tank 22. At this time, a chemical is added from the chemical addition means 97. As a result, the cleaning liquid for the UF membrane is replaced with a new one.

  The cleaning liquid discharged to the cleaning liquid tanks 26 and 28 is used for cleaning the safety filter 16 and the RO membrane unit 18. By reusing the waste water from the previous water treatment facility for washing the water treatment facility in the subsequent stage, the amount of chemical used in the water treatment equipment and the amount of waste water discharged from the waste water can be reduced, reducing the cost of chemicals and the burden of waste liquid treatment. This can reduce the cleaning cost. The cleaning waste liquid in the cleaning liquid tank 26 may be sent to the cleaning liquid tanks 22 and 28 via the pipe 98.

  In the above embodiment, the cleaning liquid tanks 22, 26 and 28 corresponding to the filtration devices of the UF membrane unit 12, the safety filter 16 and the RO membrane unit 18 are provided, but one for two or more filtration devices. A cleaning liquid tank may be provided, and the cleaning liquid in the cleaning liquid tank may be collected and passed through a plurality of filtration devices for cleaning. A plurality of filtration devices arranged in parallel may be regarded as one filtration device, and one cleaning liquid tank may be provided for the plurality of filtration devices, or a plurality of same or different types of filtration devices may be connected in series ( Multi-stage connection) may be regarded as one filtering device, and one cleaning liquid tank may be provided for the plurality of filtering devices. For example, a plurality of UF membrane units 12 can be connected in parallel, and the cleaning liquid can be supplied to each UF membrane unit 12 from one cleaning liquid tank. Further, for example, the safety filter 16 and the RO membrane unit 18 connected in series can be regarded as one facility, and one cleaning liquid tank can be provided for the safety filter 16 and the RO membrane unit 18. A combination of filtration devices arranged in parallel or a single filtration device is not limited to this.

  However, when the frequency of cleaning of each filtration device and the components and concentration of the cleaning solution are different, it is preferable to provide a cleaning solution tank corresponding to each filtration device. By adopting such a configuration, the cleaning liquid can be sent from each cleaning liquid tank to each filtering apparatus even when the cleaning times of the respective filtering apparatuses overlap, so that the cleaning liquid need not be discarded. For example, the UF membrane unit 12 is cleaned about once a week, and the RO membrane unit 18 is cleaned about once a month.

  Further, a plurality of cleaning liquid tanks may be provided, and the cleaning waste liquid may be separated and stored according to the degree of contamination (water quality). In this case, the cleaning drainage can be reused more efficiently by selecting and using the cleaning drainage having the water quality necessary for the cleaning for each unit operation constituting the preceding filtration device.

  In the above embodiment, when the RO membrane cleaning drainage liquid stored in the cleaning liquid tank 28 is sent to the cleaning liquid tanks 22 and 26 by the pump 30, chemicals suitable for cleaning each facility may be added. Further, a means for supplying the cleaning drainage liquid from the RO membrane unit 18 to the cleaning liquid tanks 22 and 26 is provided so that the cleaning drainage liquid can be directly supplied from the RO membrane unit 18 to the cleaning liquid tanks 22 and 26 without using the cleaning liquid tank 28. It may be. Alternatively, a means for supplying the cleaning drainage liquid from the RO membrane unit 18 to the secondary side of the UF membrane unit 12 or the safety filter 16 may be provided so that the UF membrane unit 12 or the safety filter 16 is back-washed. .

  In the above embodiment, when the pump 32 allows fluid to pass through when stopped, the leading branch pipe 90 may be omitted.

  In the above embodiment, a three-stage filtration device is provided as a water treatment facility for performing chemical cleaning, and a cleaning liquid tank is provided corresponding to each filtration device. However, a water treatment facility for performing chemical cleaning other than the filtration device, and this A cleaning liquid tank corresponding to the water treatment facility may be provided to clean the water treatment facility. For example, as shown in FIG. 14, an ultraviolet irradiation device 14 </ b> A as a water treatment facility for performing chemical cleaning instead of the incidental facility 14 and a cleaning liquid tank 24 corresponding to the ultraviolet irradiation device 14 </ b> A are provided. The cleaning liquid tank 24 is connected to the main branch pipe 51 via the secondary branch pipe 71. Further, a sub branch pipe 81 provided with a pump 34 is provided in parallel with the sub branch pipe 71, and the main branch pipe 51 and the cleaning liquid tank 24 are also connected by the sub branch pipe 81. Further, the cleaning liquid tank 24 is connected to the main branch pipe 52 via the sub branch pipe 62. The cleaning liquid tank 24 stores the cleaning liquid sent from the cleaning liquid tank 28 by the pump 30. The pump 34 supplies the cleaning liquid stored in the cleaning liquid tank 24 to the primary side of the ultraviolet irradiation device 14A via the secondary branch pipe 81, the main branch pipe 51, and the connection pipe 41, and the cleaning waste liquid is connected to the connection pipe 42, By introducing it into the cleaning liquid tank 24 through the main branch pipe 52 and the sub branch pipe 62, it is possible to perform the circulation cleaning process of the ultraviolet irradiation device 14A. The other structure is the same as that of the water treatment apparatus shown in FIG. Such a cleaning liquid tank 24 may be added as a water treatment facility for performing chemical cleaning on the second water treatment facility of the water treatment apparatus shown in FIGS. Further, by providing a connecting pipe for connecting the sub branch pipe 81 and the sub branch pipe 62, the cleaning liquid from the cleaning liquid tanks 26 and 28 is passed through the ultraviolet irradiation device 14A and the safety filter 16 as in FIGS. The UF membrane unit 12 can be backwashed.

  In the water treatment apparatus according to the above embodiment, a booster pump may be provided between the safety filter 16 and the RO membrane unit 18. Since the booster pump is a water treatment facility that does not perform cleaning with a chemical solution, a cleaning solution tank corresponding to the booster pump is not installed. When a booster pump is provided, a branch pipe or a connecting pipe is provided so as to bypass the booster pump when the cleaning liquid from the cleaning liquid tank 28 is supplied to the subsequent water treatment facility.

  It is not necessary to install a corresponding cleaning liquid tank for all of the water treatment facilities that perform cleaning with a chemical solution, and there may be a water treatment facility in which a corresponding cleaning liquid tank is not installed. In this case, the cleaning liquid is fed from the cleaning liquid tank corresponding to the other water treatment equipment, and the forward washing or the back washing is performed.

  In the water treatment apparatus according to the above embodiment, the UF membrane unit 12 and the like are provided as an example of the water treatment facility for pretreatment of the RO membrane unit 18, but the pretreatment facility is not limited to these, and microfiltration ( MF) Membrane filtration device and filter, ion exchange device, electrodialysis device, sand filtration device, activated carbon filtration device, treated water tank, biological treatment tank, biological activated carbon tower, decarbonation tower, degassing membrane device, UV An irradiation device, a pump, or the like can be used. Among these, the sand filtration device, the activated carbon filtration device, and the UV irradiation device can be cleaned with a chemical solution, and a cleaning solution tank may be provided for these facilities.

  The pretreatment equipment such as a membrane filtration device may be a dead end type or a cross flow type.

  In the above embodiment, the cleaning liquid is introduced from the primary side or the secondary side of the water treatment facility for cleaning, but the cleaning liquid may be supplied from a dedicated cleaning nozzle in accordance with the characteristics of the facility.

  In the above embodiment, the treated water of the corresponding filtration device is supplied to each cleaning liquid tank, but the treated water of the front-side equipment is used as the cleaning liquid for the rear-side equipment. Good. For example, a part of the treated water of the UF membrane unit 12 may be supplied to the cleaning liquid tank 26 and mixed with the cleaning liquid of the safety filter 16.

  In the above-described embodiment, one or a plurality of high-order water treatment facilities may be further provided in the subsequent stage of the RO membrane unit 18.

12 UF membrane unit 14 Auxiliary equipment 16 Security filter 18 RO membrane unit 22, 24, 26, 28 Cleaning liquid tank 30-34, 36, 38 Pump 40 Raw water piping 41, 42, 43 Connection piping 44 Treated water outlet 51, 52, 53 Main branch pipe 61, 62, 63 Sub branch pipe 65 Connection pipe 71, 72, 73, 81, 82, 83 Secondary branch pipe 90, 92 Lead branch pipe 94 Trail branch pipe 96, 97 Chemical addition means

Claims (14)

A plurality of water treatment facilities connected in series so that the water to be treated is sequentially passed;
A plurality of cleaning liquid tanks provided corresponding to each water treatment facility and storing a cleaning liquid for cleaning each water treatment facility,
With
Two or more of a plurality of cleaning liquid tanks are connected to each other, and in the connected cleaning liquid tanks, the cleaning liquid in one cleaning liquid tank is sent to another cleaning liquid tank.   2. The water treatment apparatus according to claim 1, wherein the cleaning liquid is fed from the upstream side and / or the downstream side to at least one of the plurality of water treatment facilities from the cleaning liquid tank. In claim 1 or 2,
It is further equipped with a water treatment facility that does not have a corresponding cleaning solution tank,
A water treatment apparatus, wherein a cleaning liquid in at least one of the plurality of cleaning liquid tanks is sent to a water treatment facility not provided with the corresponding cleaning liquid tank. In any of claims 1 to 3,
It is further equipped with water treatment equipment that is not washed,
A water treatment apparatus characterized in that a pipe for feeding a cleaning liquid from one cleaning liquid tank to another cleaning liquid tank is provided so as to bypass a water treatment facility where the cleaning is not performed. In a water treatment apparatus having n (n is an integer of 3 or more) water treatment equipment connected in series so that water to be treated is sequentially passed,
Of the n water treatment facilities, m (m is an integer from 2 to n) water treatment facilities are equipment to be cleaned,
Corresponding to the first to m-th equipment to be cleaned, first to m-th cleaning liquid tanks are installed,
First to m-th circulating cleaning means for circulating the cleaning liquid in the k-th (k is an integer of 1 to m) cleaning liquid tank through the k-th equipment to be cleaned in the normal cleaning direction;
A liquid feeding means for feeding the cleaning liquid in any one of the first to m-th cleaning liquid tanks to another cleaning liquid tank;
A water treatment apparatus comprising: In claim 5,
The jth (j is an integer from 1 to (n-1)) water treatment facility and the (j + 1) th water treatment facility are connected, and the treated water of the jth water treatment facility is connected to the (j + 1) th water treatment facility. First to (n-1) connecting pipes to be introduced into the water treatment facility;
First to (n-1) main branch pipes branching from each connection pipe;
Further comprising
The i-th (i is an integer from 2 to (n-1)) water treatment facility is a facility to be cleaned,
The (i-1) main branch pipe is connected to a cleaning liquid tank corresponding to the equipment to be cleaned by a sub branch pipe,
The i-th main branch pipe is connected to the cleaning liquid tank by a sub branch pipe,
At the time of circulating cleaning of the equipment to be cleaned, the cleaning liquid in the cleaning liquid tank passes through the secondary branch pipe, the (i-1) main branch pipe, and the (i-1) connection pipe. Supplied to the primary side,
A water treatment apparatus characterized in that the cleaning drainage of the equipment to be cleaned is circulated to the cleaning liquid tank through the i-th connecting pipe, the i-th main branch pipe and the sub-branch pipe. In claim 5 or 6,
The water treatment apparatus characterized in that the cleaning frequency of the equipment to be cleaned corresponding to the cleaning liquid tank that is the liquid supply source of the cleaning liquid by the liquid supply means is higher than the cleaning frequency of the equipment to be cleaned that corresponds to the cleaning liquid tank that is the liquid destination. . In a water treatment apparatus having n (n is an integer of 3 or more) water treatment equipment connected in series so that water to be treated is sequentially passed,
Of the n water treatment facilities, m (m is an integer from 2 to n) water treatment facilities are to-be-cleaned facilities.
Corresponding to the first to m-th equipment to be cleaned, first to m-th cleaning liquid tanks are installed,
First to (m-1) th to circulate the cleaning liquid in the sth cleaning liquid tank in the backwash direction for the sth (s is an integer of 1 to (m-1)) equipment to be cleaned. Circulating back washing means
Liquid feeding means for feeding the cleaning liquid in the cleaning liquid tank on the front stage or the rear stage to the s-th cleaning liquid tank;
A water treatment apparatus comprising: In claim 8,
The jth (j is an integer from 1 to (n-1)) water treatment facility and the (j + 1) th water treatment facility are connected, and the treated water of the jth water treatment facility is connected to the (j + 1) th water treatment facility. First to (n-1) connecting pipes to be introduced into the water treatment facility;
First to (n-1) main branch pipes branching from each connection pipe;
Further comprising
The i-th (i is an integer from 2 to (n-1)) water treatment facility is a facility to be cleaned,
The (i-1) main branch pipe is connected to the cleaning liquid tank corresponding to the equipment to be cleaned by the (i-1) sub branch pipe,
The i-th main branch pipe is connected to the cleaning liquid tank by a sub branch pipe,
At the time of reverse cleaning of the equipment to be cleaned, the cleaning liquid in the cleaning liquid tank is supplied to the secondary side of the equipment to be cleaned through the sub-branch pipe, the i-th main branch pipe, and the i-th connection pipe.
The cleaning drainage of the equipment to be cleaned is transferred to the cleaning liquid tank via the (i-1) connecting pipe, the (i-1) main branch pipe and the (i-1) sub branch pipe. A water treatment device that is circulated. In claim 9,
The i-th main branch pipe is connected to the cleaning liquid tank on the rear stage side by the i-th sub branch pipe,
Before the circulating backwashing of the equipment to be cleaned, the cleaning liquid in the cleaning liquid tank on the rear stage side is supplied to the equipment to be cleaned via the i-th sub-branch pipe, the i-th main branch pipe, and the i-th connection pipe. Supplied to the secondary side of
The drainage of the equipment to be cleaned is cleaned through the (i-1) connecting pipe, the (i-1) main branch pipe and the (i-1) sub branch pipe. A water treatment apparatus which is introduced into a cleaning liquid tank corresponding to equipment. In any of claims 5 to 10,
The first to m-th equipment to be cleaned is a filter, a microfiltration membrane device, an ultrafiltration membrane device, a reverse osmosis membrane device, or an ultraviolet irradiation device,
The water treatment apparatus which is not a facility to be cleaned is a treated water tank, a biological treatment tank, a biological activated carbon tower, a pump, a decarbonation tower, or a degassing membrane apparatus. In any of claims 5 to 11,
A water treatment apparatus, further comprising a high-order water treatment facility into which treated water of the nth water treatment facility is introduced after the nth water treatment facility. A cleaning method for cleaning at least some of the water treatment facilities of the water treatment device according to any one of claims 5 to 7,
Cleaning the k-th equipment to be cleaned by circulating a cleaning liquid in a forward direction between the k-th equipment to be cleaned and the k-th cleaning liquid tank;
After circulating cleaning of the k-th equipment to be cleaned, the cleaning liquid in the k-th cleaning liquid tank is sent to another cleaning liquid tank and used as the cleaning liquid for the cleaning equipment corresponding to this cleaning liquid tank. Cleaning method for water treatment equipment. A cleaning method for cleaning at least a part of water treatment equipment of the water treatment device according to any one of claims 8 to 10,
A step of feeding the cleaning liquid in the rear cleaning liquid tank to the s-th cleaning liquid tank;
Cleaning the s-th equipment to be cleaned by circulating a cleaning liquid in the backwash direction between the s-th equipment to be cleaned and the s-th cleaning liquid tank;
A method for cleaning a water treatment facility comprising:

Images