TWI820133B - Diagnostic device for reverse osmosis systems - Google Patents

Abstract

The present invention provides a diagnostic device for a reverse osmosis system, which can easily determine the cause of malfunction. A diagnostic device for a reverse osmosis system that diagnoses the operating status of an RO system. The RO system includes an RO device 5 that performs membrane filtration of water to be treated. The diagnostic device for the reverse osmosis system includes: an input part for the concentration ratio; a storage part that stores data indicating the relationship between the concentration ratio and the abnormal operation state of the reverse osmosis system; and a determination part 35 based on the concentration ratio input by the input part and the information stored in the storage part The stored data determines the cause of malfunction of the reverse osmosis device.

Description

Diagnostic device for reverse osmosis system

The present invention relates to a diagnostic device used to diagnose the causes of malfunction of a reverse osmosis system that performs reverse osmosis (RO) treatment on water to be treated.

In water treatment, various wastewater treatment, wastewater recovery, etc. using well water, industrial water, tap water, etc. as raw water, the following method is performed. That is, a coagulant is added to the raw water to remove suspended matter and colloid components in the raw water. Or after organic matter and the like are aggregated and coarsened, solid-liquid separation is performed by sedimentation, suspension, filtration, membrane filtration, etc., or the following treatment is performed, that is, turbidity and sterilization are performed by membrane filtration alone to recover the treated water.

Generally, causes of membrane clogging of RO membranes include: (i) excessive turbidity in the water supply; (ii) adhesion of scale and slime; (iii) in the case of pretreatment. Poor pre-treatment, etc. As a countermeasure, the following operations can be performed.

Regarding (i), for example, the sludge density index (SDI) of RO water supply is measured. When the SDI or above is specified, respond by changing the pre-processing conditions, etc. Regarding (ii), for example, the water quality of RO water supply, RO treated water, and RO concentrated water is measured to optimize the recovery rate. Regarding (iii), confirm the addition concentration of the flocculant in the pretreatment, and if it is above the allowable addition concentration, adjust it to below the allowable addition concentration.

When the filtration resistance of the RO membrane increases, backwashing or cleaning with chemicals such as acid and alkali is performed (Patent Document 1, etc.). [Prior art documents] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2016-185520

There are many reasons for RO membrane clogging, such as excessive turbidity in the water supply, adhesion of scale or slime, and poor pretreatment. The response strategies vary depending on the cause, so it is necessary to accurately determine the cause and establish a response strategy quickly and appropriately.

An object of the present invention is to provide a diagnostic device for a reverse osmosis system that can easily determine the cause of malfunction of a reverse osmosis (RO) system. [Means to solve the problem]

The diagnostic device of the reverse osmosis system of the present invention is a diagnostic device for diagnosing the operating status of the reverse osmosis system. The reverse osmosis system includes a reverse osmosis device that performs reverse osmosis treatment on the treated water. The diagnostic device of the reverse osmosis system The device includes: an input unit for a concentration ratio of the reverse osmosis system; a storage unit that stores data indicating a relationship between the concentration ratio and an abnormal operation state of the reverse osmosis system; and a determination unit based on the concentration input by the input unit. The magnification and the data stored in the storage part are used to determine the cause of malfunction of the reverse osmosis device.

In one aspect of the present invention, the determination unit compares the concentration ratio of the non-precipitable standard substance with the concentration ratio of the organic substance.

In one aspect of the present invention, the determination unit compares the concentration ratio of the non-precipitable standard substance with the concentration ratio of the scale-forming substance.

In one aspect of the present invention, the non-precipitable standard material is Na, and the scale-forming material is Si, Ca, or Mg.

In one aspect of the present invention, when the primary-side flow path differential pressure of the reverse osmosis device is a predetermined value or more, and when the rising rate of the primary-side flow path differential pressure is a predetermined value or more, the correction flux (flux) The above-mentioned diagnosis is performed when the condition is outside the predetermined range or when the decreasing speed of the correction flux is equal to or higher than the predetermined value. [Effects of the invention]

According to the present invention, the cause of malfunction of the RO system can be appropriately determined.

FIG. 1 is a block diagram of the RO system according to the embodiment. The raw water is coagulated and filtered by the pre-treatment device 1 and then supplied to the RO device 5 via the pump 2, valve 3 and pipe 4. In the above embodiment, as the pretreatment device 1, as shown in Fig. 4, a device including the following components is used: a coagulation treatment device 1a; a filter device 1b for filtering the coagulation treatment water; and a relay tank 1d. Store filtered water; but not limited to this. Symbol 1c represents an inflow pipe of filtered water to the relay tank 1d, and 1e represents a pipe from the relay tank 1d to the pump 2. A pH meter 19 is provided in the pipe 1e.

As the filtration device 1b, a gravity filter, a pressure filter, a microfiltration (MF) membrane module, an ultrafiltration (UF) membrane module, etc. are preferred. In the above embodiment, hollow fibers are used. UF membrane module.

The permeated water of the RO membrane 5a of the RO device 5 is taken out as processed water through the pipe 6 and the valve 7, and the raw water that has not passed through the RO membrane 5a is taken out as concentrated water through the pipe 17 and the valve 18. The pipe 4, the pipe 6, and the pipe 17 are provided with a pressure sensor 8, a pressure sensor 9, and a pressure sensor 27, respectively. The pipe 6 is further provided with a flow meter 9A and a thermometer 9B. The detection values of the flow meter 9A, the pressure sensor 8, the pressure sensor 9, the pressure sensor 27, and the thermometer 9B are input to the calculation circuit 20, and a correction flux (correction transmission flux) is calculated.

The pressure detected by the pressure sensor 8 and the pressure sensor 27 is input to the calculation circuit 20, and the difference between them is calculated as the primary side flow path differential pressure. When the differential pressure is too large (above the predetermined value a), or the rising speed of the differential pressure is too large (above the predetermined value b), a signal is sent to the alarm circuit 21 to generate an alarm by sound and/or light, and A signal is sent to the diagnostic device 30 to perform diagnosis. When the correction flux calculated based on the detected flow rate of the flow meter 9A is outside the predetermined range, or the decreasing speed of the correction flux is greater than or equal to a predetermined value, a signal is also sent to the alarm circuit 21 to generate a sound and /or an alarm formed by light, and sends a signal to the diagnostic device 30 to perform diagnosis.

As shown in FIG. 2 , the diagnostic device 30 includes a main body 31 and a liquid crystal display panel 36 as an input unit having a touch switch function. The main body part 31 includes a data collection part 32 , a data storage part 33 , a database (storage part) 34 and a determination part 35 .

The main body 31 includes a central processing unit (CPU) (central processing unit), flash memory (flash memory), read only memory (Read Only Memory, ROM), and random access memory (random access memory). A computer composed of access memory (RAM), hard disk, etc.

By the CPU of the main body unit 31 executing the management program, the functions of the data collection unit 32, the data storage unit 33, the database 34 and the determination unit 35 are realized.

In addition to receiving primary side flow path differential pressure and corrected flux data, the data collection unit 32 also receives concentration rate data from the display panel 36 . The data storage unit 33 stores each data and the judgment results described below. The database 34 stores data indicating the relationship between each concentration ratio and the cause of malfunction of the RO system.

The determination unit 35 determines the cause of the malfunction based on the concentration rate data collected by the data collection unit 32 from the display panel 36 and the cause data in the database 34 , and displays the cause on the display panel 36 .

As shown in Figure 3, when there is an abnormality in the differential pressure of the primary side flow path of the RO device 5 (when the differential pressure or the differential pressure rise rate is above a predetermined value), or when there is an abnormality in the correction flux of the RO device 5 (when the flux is below a predetermined value, or when the flux decrease rate is above a predetermined value), activate the alarm, and use the following together with the ten key part (not shown), for example The concentration input screen of each component is displayed on the display panel 36, and the concentration of each component is input in the input field on the right side of each item using the ten-key unit. The input operation is performed by the person in charge of operating the RO system. Furthermore, in conjunction with the alarm operation, the display panel 36 may display an alarm switch, and when the operation manager or the like touches the alarm switch, the input screen may be displayed.

Water supply Na concentration □□□ mg/L Concentrated water Na concentration □□□ mg/L Water supply Ca concentration □□□ mg/L Concentrated water Ca concentration □□□ mg/L Water supply Mg concentration □□□ mg/L Concentrated water Mg concentration □□□ mg/L Si concentration in water supply □□□ mg/L Concentrated water Si concentration □□□ mg/L Water supply TOC (Total Organic Carbon, total organic carbon) concentration □□□ mg/L Concentrated water TOC concentration □□□ mg/L Water supply UV (ultraviolet, ultraviolet light) concentration 260 mg/L Concentrated water UV260 concentration □□□ mg/L

The Na is a non-precipitable standard material, and Ca, Mg, and Si are precipitable standard materials (scale-forming substances). UV260 refers to organic substances measured by ultraviolet absorption photometry with a wavelength of 260 nm. As non-precipitable standard materials, K, Cl, etc. can also be used. Moreover, as a precipitable standard material, Ba, Sr, etc. can be used.

After inputting the concentrations of all items, touch the input (enter, Ent) switch indicating the end of the answer. Thereby, the answer data is sent from the display panel 36 to the data collection unit 32 .

The determination unit 35 calculates the concentration ratio of each component based on the concentration of each component in the feed water and concentrated water. Furthermore, the concentration ratio of Na was compared with a reference value that was larger than each concentration ratio of TOC and UV260 by a predetermined value. That is, when the concentration ratio of Na is n, the concentration ratio of TOC is t, and the concentration ratio of UV260 is u, it is determined whether n>(t+α) and n>(u+β) respectively. (t+α, u+β are reference values). Furthermore, when the Na concentration ratio is greater than each reference value, it is determined that organic contamination has occurred, and when it is less than the reference value, it is determined that organic contamination has not occurred.

In addition, the concentration rate of Na is compared with a reference value that is greater than the concentration rate of Ca, Mg, and Si by a predetermined value or more. When the concentration rate of Na is greater than each reference value, it is determined that Ca, Mg, or Si scale is generated. When the pollution is less than the reference value, it is judged that there is no pollution caused by Ca, Mg and Si scale.

Furthermore, when the flux exceeds the prescribed upper limit, it is determined that the RO membrane has aged, and a message indicating that the RO membrane should be replaced is displayed on the display panel.

In this way, when an abnormality occurs in the RO device of the RO system, the cause can be accurately known, and effective countermeasures can be quickly taken based on the cause.

Furthermore, in the above-described form, the concentration ratio of each component of the feed water and the concentrated water is input to calculate the concentration ratio of each component. However, the concentration ratio of each component can also be directly input.

Although the present invention is not particularly limited, examples of the raw water include tap water, industrial water, well water, and all drainage water.

The coagulant and coagulant aid used in the coagulation treatment are not particularly limited, but it is desirable to use an iron-based coagulant. Furthermore, depending on the water quality, agglutination treatment may be omitted.

When an iron-based coagulant is used, pH 4.5 to pH 7.0 is preferred, and pH 5.0 to pH 6.0 is particularly preferred. If the pH is too low, there is a risk of membrane clogging by iron leakage. If the pH is too high, there is a possibility of poor aggregation.

It is better to add an oxidizing agent (usually sodium hypochlorite) to the raw water. The preferred addition amount is about 0.3 mg/LasCl ₂ to 1.0 mg/LasCl ₂ .

When a membrane filtration module is used in the filtration device 1b, it can be either a crossflow method or a total volume filtration method.

The processing steps using membrane filtration modules include water flow, air bubbling, backwashing, and water filling. The time for filtering water is 20 to 40 minutes. The initial inter-membrane differential pressure (the difference between the primary side pressure and the secondary side pressure of the element or module) is around 0.02 MPa ~ 0.05 MPa and operates. When the differential pressure between the membranes is 0.07 MPa to 0.10 MPa, it is better to perform in-situ cleaning. The material of the membrane is polyvinylidene Fluoride (PVDF), which has good chemical resistance and is preferred. The preferred pore diameter is 0.01 μm to 0.5 μm.

The amount of brine in the RO device 5 is preferably 3.6 m ³ /h or more. The RO membrane is not particularly limited, but it is preferably an ultra-low pressure membrane with a standard pressure of 0.735 MPa, and the membrane area is preferably 35 m ² to 41 m ² . Preferably, the initial pure water flux is: 1.0 m/d (25℃) or more, 0.735 MPa, and the initial desalination rate is: 98% or more. It is preferable to set the recovery rate so that the calcium hardness Langelier Index is 0 or less. It is preferable to set the recovery rate so that the silica concentration in the brine is within the solubility range. Furthermore, the recovery rate is usually 50% to 80%.

The present invention has been described in detail using specific forms. However, it will be apparent to those skilled in the art that various changes can be made without departing from the intention and scope of the present invention. This application is based on Japanese Patent Application No. 2018-97219 filed on May 21, 2018, the entire text of which is incorporated by reference.

1‧‧‧Pretreatment device 1a‧‧‧Agglutination treatment device 1b‧‧‧filtration device 1c‧‧‧Filtered water inflow pipe to relay tank 1d 1d‧‧‧Relay slot 1e‧‧‧Piping (piping from relay tank 1d to the pump 2) 2‧‧‧Pump 3, 7, 18‧‧‧ valve 4, 6, 17‧‧‧Piping 5‧‧‧RO device 5a‧‧‧RO membrane 8, 9, 27‧‧‧Pressure sensor 9A‧‧‧Flowmeter 9B‧‧‧Thermometer 19‧‧‧pH meter 20‧‧‧Arithmetic circuit 21‧‧‧Alarm circuit 30‧‧‧Diagnostic device 31‧‧‧Main part 32‧‧‧Data Collection Department 33‧‧‧Data Storage Department 34‧‧‧Database (Storage Department) 35‧‧‧Judgment Department 36‧‧‧Display panel

Figure 1 is a block diagram of the RO system. FIG. 2 is a block diagram of the diagnostic device of the RO system. FIG. 3 is a flowchart showing a diagnostic method of the RO system. Fig. 4 is a structural diagram of the pre-processing device.

1‧‧‧Pretreatment device

2‧‧‧Pump

3, 7, 18‧‧‧ valve

4, 6, 17‧‧‧Piping

5‧‧‧RO device

5a‧‧‧RO membrane

8, 9, 27‧‧‧Pressure sensor

9A‧‧‧Flowmeter

9B‧‧‧Thermometer

19‧‧‧pH meter

20‧‧‧Arithmetic circuit

21‧‧‧Alarm circuit

30‧‧‧Diagnostic device

Claims (3)

A diagnostic device of a reverse osmosis system for diagnosing the operating status of the reverse osmosis system. The reverse osmosis system includes a reverse osmosis device that performs reverse osmosis treatment of treated water. The diagnostic device of the reverse osmosis system includes: the treated water. An input unit for the Na concentration, TOC concentration, and UV260 (organic substance measured by ultraviolet absorbance photometry with a wavelength of 260 nm) concentration of the treated water and the concentrated water of the reverse osmosis device; and a determination unit, based on the input Na concentration, TOC concentration and UV260 concentration calculate the concentration ratio of Na, TOC and UV260. When the concentration ratio of Na is larger than the concentration ratio of TOC by more than a specified value, or when the concentration ratio of Na is larger than the concentration ratio of UV260 by a specified value, it is judged Organic contamination occurs in reverse osmosis equipment. A diagnostic device of a reverse osmosis system for diagnosing the operating status of the reverse osmosis system. The reverse osmosis system includes a reverse osmosis device that performs reverse osmosis treatment of treated water. The diagnostic device of the reverse osmosis system includes: the treated water. an input unit for Na concentration, Ca concentration, Mg concentration, and Si concentration of the treated water and the concentrated water of the reverse osmosis device; and a determination unit that calculates Na, Ca, The concentration ratio of Mg and Si is when the concentration ratio of Na is larger than the concentration ratio of Ca by more than a specified value, or when the concentration ratio of Na is larger than the concentration ratio of Mg by a specified value, or when the concentration ratio of Na is larger than that of Si. When the concentration ratio is greater than the specified value, it is determined that the reverse osmosis device is contaminated by Ca, Mg or Si scale. A diagnostic device for a reverse osmosis system as described in claim 1 or 2, wherein when the primary side flow path differential pressure of the reverse osmosis device is above a predetermined value, the primary side flow path differential pressure rises The diagnosis is performed when the speed is equal to or greater than a predetermined value, when the correction flux is outside a predetermined range, or when the decreasing speed of the corrected flux is equal to or greater than a predetermined value.

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