JPS5925633B2 - How to treat wastewater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently concentrating wastewater using a reverse osmosis treatment device.

Possible methods for treating washing wastewater such as washing, hand washing, and shower wastewater discharged from the atomic couplant include the evaporation method, charcoal pet method, and reverse osmosis treatment, among which reverse osmosis treatment ■ There is no need to worry about corrosion as the process is carried out at room temperature.

■ There is no problem with foaming, and there is no need to limit the amount of detergent used.

■ Less secondary waste is generated.

Because of these advantages, it has recently begun to attract attention as a method for treating wastewater containing radioactive materials, such as washing wastewater from atomic couplants.

Conventionally, washing wastewater is separated into concentrated water and clean water using a reverse osmosis treatment device, and the clean water is recovered as permeate water, while the concentrated water is returned to the washing wastewater tank and subjected to reverse osmosis treatment until it reaches a predetermined concentration. Examples of repeated reverse osmosis treatment methods for wastewater include a complete batch concentration method as shown in FIG.

That is, in Fig. 1, a is a washing wastewater tank, a washing wastewater supply pipe is installed on the upstream side of tank a, and a reverse osmosis treatment equipment supply pipe is installed at the bottom of tank a. Water pipe C is installed at ℃・℃.

The other end of the reverse osmosis treatment equipment supply water pipe C is connected to a drainage pump d.
It is connected to a reverse osmosis treatment device g via a 1-wash drainage filter e and a high-pressure pump f.

The reverse osmosis treatment equipment g is equipped with a permeated water pipe for flowing clean water (permeated water) separated by reverse osmosis treatment and a concentrated water circulation pipe i for flowing concentrated water, and the concentrated water circulation pipe i is used for pressure adjustment. It is arranged so that it circulates to the washing waste water tank a via the valve Va, the cooler j and the concentrated water flow path switching valve vb (
・Ru.

Note that k is a final concentrated water discharge pipe connected to various chambers of the temperature drum (not shown).

In such a configuration, the cleaning wastewater flows from the cleaning wastewater supply pipe to the cleaning wastewater tank a and is stored in a predetermined amount. The drainage pump d and the high-pressure pump f are driven at ℃・, coarse suspended solids in the drainage are removed by the drainage filter e, and the wastewater is sent to the reverse osmosis treatment device g as high-pressure drainage, and the above drainage is purified water and concentrated water. Separate into two parts.

The above-mentioned clean water is discharged out of the system from the permeate pipe as permeate water.

At this time, if the quality of the permeated water is unsuitable for reuse or discharge, it is treated at a higher level and then reused or discharged.

On the other hand, the concentrated water passes through the concentrated water circulation pipe i, and the pressure regulating valve Va
The water pressure is adjusted at 10°C, and after being cooled in a cooler j at 10°C, it is circulated back to the wash water tank a through a concentrated water flow path switching valve vb.

The concentrated water continues to be concentrated by repeating the above reverse osmosis treatment process.

In this process, the water level in the wash water tank a gradually decreases as the reverse osmosis treatment is repeated.

When a predetermined concentration level is reached, the concentrated water flow path switching valve vb is switched, the concentrated water circulation pipe i is connected to the final concentrated water discharge pipe, and the operation of the high pressure pump f is stopped.
The cleaning drainage supply on/off valve is opened, cleaning drainage tank a is filled with cleaning drainage tank a to a predetermined water level, high pressure pump f is driven again, cleaning drainage tank a, high pressure pump f and reverse osmosis treatment equipment supply water pipe C. The final concentrated water concentrated tens to hundreds of times remaining in the reverse osmosis treatment equipment supply water system, reverse osmosis treatment equipment g, and the concentrated water circulation system such as cooler j and concentrated water circulation pipe i is used to clean the wastewater piston. By flow action, the concentrated water is transferred to various drum chambers (not shown) via the final concentrated water discharge pipe k.

However, according to this complete batch concentration method, it takes a long time to obtain the final concentrated water that can be directly packed in drums, so when a large amount of wastewater is released, it is difficult to process the amount in one batch. Therefore, the cost of installing a large-capacity washing and drainage tank becomes expensive.

Furthermore, during one batch treatment, a storage tank is required to store the discharged wastewater, and the cost of this equipment can be quite expensive depending on the amount of discharged wastewater.

``Furthermore, in the complete batch system, the cleaning drainage supply valve,
It has the disadvantage that it is necessary to frequently operate valves such as the concentrated water flow path switching valve, making the operation extremely complicated.

Furthermore, the content of impurities in the permeate water pumped out from the reverse osmosis treatment device g is proportional to the content of impurities in the water supplied to the reverse osmosis treatment device that is supplied to the membrane surface of the reverse osmosis treatment device. In the complete batch concentration method, the content of impurities in the reverse osmosis treatment equipment feed water that is supplied to the membrane surface increases rapidly, so the content of impurities in the permeate water also increases rapidly in proportion to this. The quality of the water deteriorated rapidly, and the amount of good quality permeate water that could be reused or discharged per batch was small.

In the present invention, wastewater to be treated is supplied to a circulation tank with a predetermined capacity provided downstream of a cleaning wastewater tank, and is then supplied to a reverse osmosis treatment device via a high-pressure pump to separate the wastewater into concentrated water and permeated water. Then, the concentrated water is concentrated by repeating the process of passing it through the cooler and returning it to the circulation tank.
Until the concentration ratio is several tens of times, the water level in the circulation tank is kept constant by supplying the waste water from the waste water tank to continue concentration. It is characterized by cutting off the communication and continuing concentration, and its purpose is to eliminate the above-mentioned conventional drawbacks and provide a method for efficiently treating a large amount of wastewater.

In addition, in the present invention, the wastewater to be treated is thus supplied to the circulation tank of a predetermined capacity provided downstream of the washing wastewater tank to the reverse osmosis treatment device via the high-pressure pump, and the wastewater is converted into concentrated water. Concentration is carried out by repeating the process of separating the water from the permeated water, passing it through a cooler, and then returning it to the circulation tank. Since the water level in the circulation tank is kept constant by supplying the waste water and concentrating it continuously, a large amount of waste water can be efficiently treated. Also, the concentrated water in the circulation tank can be used as waste water from the cleaning waste water tank. Since the permeate water continues to be diluted, the quality of the permeate water does not deteriorate rapidly, and a large amount of high-quality permeate water can be obtained.

Furthermore, after the concentration ratio increases to several tens of times, the communication between the wastewater tank and the circulation tank is cut off and the wastewater is concentrated at ℃, so the final concentration ratio of the concentrated water rapidly increases. , it is possible to quickly obtain final concentrated water that can be packed into drums as is.

The most preferred embodiment of the present invention will be described below with reference to the illustrated embodiment shown in FIG. It is arranged at ℃・ru.

3 is a circulation tank supply water pipe, and the intermediate pipe 3 is equipped with a circulation tank supply water pump 4, a circulation tank supply water filter 5, and a circulation tank supply water automatic control valve V. It opens at the bottom of the cleaning drainage tank 1, and the downstream end opens at the top of the circulation tank 6.

Reference numeral 7 denotes a distribution pipe for supplying water to the circulation tank, and a manual on-off valve 2 is interposed in the intermediate pipe 7 in an open state, and one end is connected to the circulation tank supply water between the filter 5 and the valve v1. It opens into the water pipe 3, and the other end opens into the upper part of the washing and draining tank 1.

Reference numeral 8 denotes a reverse osmosis treatment equipment supply water pipe, and the intermediate pipe 8 is equipped with a high-pressure pump 9 and an automatic opening/closing valve V3 for the reverse osmosis treatment equipment supply water, and the upstream end opens at the bottom of the circulation tank 6 and the downstream The end opens into the reverse osmosis treatment device 10 .

11 is a concentrated water circulation pipe, and the intermediate pipe 11 is provided with a concentrated water pressure automatic control valve v4, a cooler 12, and a concentrated water flow path automatic switching valve v5, and one end is connected to the reverse osmosis treatment device 10.
℃, and the other end is opened at the top of the circulation tank 6.
・Ru.

In addition, 13 is a final concentrated water discharge pipe branching from the above-mentioned valve V.

14 is a reverse osmosis treatment equipment supply water flow pipe;
is equipped with an automatic opening/closing valve (6) for water flow to the reverse osmosis treatment equipment, one end of which opens into the reverse osmosis treatment equipment supply water pipe 8 located between the high pressure pump 9 and the valve (3), and the other end. It opens into the concentrated water circulation pipe 11 located between the reverse osmosis treatment device 10 and the valve v4.

15 is a permeated water distribution pipe, one end of which opens into the reverse osmosis treatment device 10 and the other end into the side wall of the permeated water tank 16; and 17, one end which opens into the bottom of the permeated water tank 16. The intermediate pipe 17 is equipped with a permeate pump 18 and a permeate flow path automatic switching valve v7, and the volume valve v7 is switched so that the other end is connected to the upper part of the cleaning drainage tank 1. The open permeated water tank 19 or the other end is disposed so as to communicate with one end of each of the recovered water supply pipes 20 (not shown) which open to the recovered water monitor tank.

In addition, FMCIA is a flow rate integration indicator installed in the circulation tank supply water pipe 3, which measures and integrates the flow rate of cleaning wastewater flowing into the water pipe 3, and calculates the total supply flow rate according to a predetermined concentration ratio. When a specified flow rate is reached, a command alarm is automatically issued.

LICA is a water level indicating adjustment alarm installed in the circulation tank 6, and it detects the water level in the tank 6, and also detects changes in the water level and concentration of the washing waste water by supplying washing waste water to the circulation tank 6. The designated water level in the tank 6 is automatically adjusted according to the water level change caused by the change in water level, and a command alarm is automatically issued when the water level in the tank 6 reaches the designated water level.

CIA-1 is a conductivity indicator and alarm meter for the reverse osmosis treatment equipment supply water, which is disposed between the circulation tank 6 and the high pressure pump 9 of the reverse osmosis treatment equipment supply water pipe 8; In addition to measuring the concentration of impurities contained in the reverse osmosis treatment equipment supply water flowing through the flow through electrical conductivity, it also indicates a predetermined electrical conductivity, and automatically when the electrical conductivity of the supplied water reaches a predetermined indicated value. It is used to send out command warnings.

TIA and PIA are the high pressure pump 9 of the reverse osmosis treatment equipment supply water pipe 8 and the reverse osmosis treatment equipment supply water flow pipe 1.
A temperature indicating alarm meter and a pressure indicating alarm meter are disposed between the branch point 4 and the water supply pipe 8, and the former measures the temperature of the reverse osmosis treatment equipment supply water flowing in the supply water pipe 8 and indicates a predetermined temperature. Moreover, when the temperature of the supplied water reaches a predetermined indicated value, a command and alarm is automatically sent out.The latter measures the pressure of the supplied water, indicates the predetermined pressure, and It automatically issues a command alarm when the pressure reaches a predetermined indicated value.

PIC is the reverse osmosis treatment device 1 of the concentrated water circulation pipe 11
This is a pressure indicating regulator installed between 0 and the automatic concentrated water pressure control valve v4, which measures the pressure of concentrated water and automatically adjusts the pressure of the concentrated water to a predetermined strength based on the measured value. This is to adjust the instructions accordingly.

FIC and CIA-2 are a flow rate indicating controller and a conductivity indicating alarm meter for permeated water disposed in the permeated water distribution pipe 15, and the former measures the flow rate of permeated water flowing inside the permeated water distribution pipe 15. At the same time, the flow rate of the permeated water is instructed and adjusted to a predetermined value based on the measured value. It automatically issues a command alarm when the temperature reaches a predetermined indicated value.

LS is a water level switch disposed in the permeated water tank 16, which detects the water level of the tank 16 and is activated when the water level of the tank 16 reaches a predetermined height.

In addition, the above-mentioned flow rate integration instruction alarm FMCIA, the above-mentioned circulation tank pump 4, and the above-mentioned circulation tank supply water automatic control valve V1
and the permeated water flow path automatic switching valve V7, between the water level indication adjustment alarm meter LICA and the circulation tank supply water automatic control valve v1, the high pressure pump 9 and the concentrated water flow path automatic switching valve v5, Between the conductive dust indicator and alarm meter ClA1 for the reverse osmosis treatment equipment supply water, the concentrated water flow path automatic switching valve V5 and the automatic control valve V1 for the circulation tank supply water, the temperature indication and alarm meter TIA and the reverse osmosis treatment equipment supply Automatic on-off valve V3 for water and automatic on-off valve V6 for the flow of water supplied to the reverse osmosis treatment equipment, and the pressure indicator and alarm meter PI
Between A and the automatic opening/closing valve V3 for water supplied to the reverse osmosis treatment equipment and the automatic opening/closing valve ■6 for water flow supplied to the reverse osmosis treatment equipment, between the pressure indicating regulator PIC and the automatic concentrated water pressure control valve v4, Between the flow rate indicating controller FIC and the concentrated water pressure automatic control valve v4, the permeated water conductive dust indicator and alarm meter CIA-2 and the permeated water flow path automatic switching valve V7
between the water level switch LS and the permeated water pump 18.
are connected by electrical signal transmission lines to
Ru.

Since this embodiment is configured as described above, cleaning wastewater containing radioactive substances as impurities such as laundry, hand washing and shower wastewater discharged from a nuclear plant is transferred from the washing wastewater supply pipe 2 to the washing wastewater. After the water is injected and stored in the tank 1, it flows through the circulation tank supply water pipe 3 by the operation of the circulation tank pump 4, and after coarse suspended matter in the water is removed by the circulation tank filter 5, the automatic control valve for the circulation tank supply water is opened. The flow rate flowing through V1 is integrated and measured by the flow rate integration indicator FMCIA, and is supplied to the circulation tank 6 up to a predetermined water level.

The waste water flows out from the bottom of the circulation tank 6 into the reverse osmosis treatment equipment supply water pipe 8 as reverse osmosis treatment equipment supply water, conductive dust is measured by the conductive dust indicator and alarm meter CIA-1, and the high pressure pump 9 The pressure is increased and the temperature and pressure are measured by the temperature indicator and alarm meter TIA and the pressure indicator and alarm meter PIA, and the valve V is in the open state.
3, the water is pressurized into a reverse osmosis treatment device 10 and separated into clean water and concentrated water.

The concentrated water flows through the concentrated water circulation pipe 11, the pressure is measured by the pressure indicator controller PIC, and the pressure is adjusted to a predetermined pressure by the valve V4, then cooled by the cooler 12, and passed through the valve V5 at 10°C. and is returned to the circulation tank 6.

Furthermore, the concentrated water returned to the circulation tank 6 is diluted with washing waste water that is continuously supplied until a constant water level is reached by the water level indicator LICA and the valve v1, and is then sent to the reverse osmosis treatment device 10 again by the operation of the high pressure pump 9. It continues to be concentrated.

By repeating such reverse osmosis treatment process, the concentration ratio of the cleaning wastewater is several tens of times, that is, when the water level in the circulation tank is constant, the amount of cleaning wastewater that is held up in the system is several tens of times as much as the circulation tank. 6 is measured by the flow rate integration indicator alarm meter FMCIA, the same alarm meter FMCI
The valve V1 is opened by the A-1 signal, the communication between the cleaning drainage tank 1 and the circulation tank 6 is cut off, and the cleaning drainage water is returned to the cleaning drainage tank 1 through the cleaning drainage distribution pipe 7.

In addition, the said concentration magnification is shown by the following formula.

However, the amount of hold-up in the system is the total volume held in the piping that communicates the circulation tank, the high-pressure pump, the reverse osmosis treatment equipment, the cooler, and each of the above devices, etc. in °C.

In this case, the communication between the wash water tank 1 and the circulation tank 6 may be cut off by stopping the operation of the circulation pump 4 in response to a signal from the alarm meter FMCIA, or the communication between the wash water tank 1 and the circulation tank 6 may be interrupted. When the measured value of the conductive dust indicator and alarm meter CIA-1 reaches the indicator type conductivity, a signal closes the valve V1.
It is also possible to cut off the communication between the cleaning drainage tank 1 and the circulation tank 6 by closing the tank.

In this state, as shown in Fig. 1, reverse osmosis is carried out using the circulation tank 6 → high pressure pump 9 → valve v3 → reverse osmosis treatment device 10 → valve v4 → cooler 12 → valve v5 → circulation tank 6 and the C/C load system. Continue the concentration process by repeating the process.

(Hereinafter referred to as the final concentration step.

) In this final concentration step, the water level in the circulation tank 6 is lowered until the final concentration ratio reaches several tens to hundreds of times.

Note that the final concentration ratio is expressed by the following formula.

This final concentration magnification is measured by measuring the water level in the circulation tank 6 with the water level indication adjustment alarm meter ICA, and the water level in the circulation tank 6 decreases due to concentration, and the water level corresponds to the predetermined final concentration magnification. When this is measured, the high pressure pump 9 is stopped by a signal from the water level indication adjustment alarm meter LICA, and the valve 5 is switched so that the concentrated water circulation pipe 11 is brought into communication with the final concentrated water discharge pipe 13.

In this case, the high pressure pump 9 may be stopped or V5 may be switched based on the measured value of the conductivity indicator/alarm meter CIA-1 for the water supplied to the reverse osmosis treatment equipment.

At the water level, the valve V1 was opened by the electric signal from the water level indicator/adjustment alarm meter LICA or the conductivity indicator/alarm meter CIA-1, and the cleaning waste water was filled to the specified water level in the circulation tank 6, and the specified water level was reached. Water level indication adjustment alarm meter I,
After checking with ICA, the high-pressure pump 9 is operated based on the signal, and the piston flow action of the cleaning waste water is used to
The final concentrated water held up in the system in the final concentrated state at a temperature of .degree. C. is sent from the final concentrated water discharge pipe 13 to various chambers of a drum, not shown.

Whether the final concentrated water in the system has been completely defrosted can be confirmed by measuring changes in the water level in the circulation tank 6 using the water level indicator adjustment alarm meter LICA.

On the other hand, the above-mentioned clean water becomes permeated water and flows through the permeated water distribution pipe 15, and the flow rate in the interpipe 15 is measured by the flow rate indicating controller FIC, and the pressure of the valve v4 is adjusted based on the measured value by the pressure indicating regulator P.
The permeate water is adjusted by the IC so that the flow rate in the permeate flow pipe 15 is automatically adjusted to the same flow rate, and the permeate water is supplied to the permeate tank 16 while its conductivity is measured by the conductivity indicator and alarm meter CIA-2. .

Further, when the water level of the permeated water stored in the tank 16 rises to the same level as the installation position of the reverse osmosis treatment device 10, the water level switch LS is activated, and the permeated water electrically connected to the water level switch LS is activated. When the pump 18 operates, the permeated water flows from the bottom of the permeated water tank 16 to the permeated water discharge pipe 17, passes through the valve 7, is stored in a temperature/recovered water monitor tank (not shown), and is then reused or discharged as cleaning water, etc. .

In addition, when the cleaning wastewater is concentrated to a predetermined concentration ratio (approximately several tens of times) through the above-mentioned concentration process, the valve v1 is closed by the electrical signal from the flow integration indicator FMCIA, and the cleaning wastewater tank 1 is closed. Communication with the circulation tank 6 is cut off, and at the same time, the valve V7 is switched by an electric signal from the alarm meter FMCIA, and the permeated water discharge pipe 17 is communicated with the permeated water return pipe 19. is returned to the cleaning drainage tank 1.

In this case, the conductivity of the permeated water flowing in the permeated water distribution pipe 15 is measured by the conductivity indicator alarm meter CI A-2 for permeated water, and when the measured value becomes the indicator type conductivity, the alarm meter C.I.A.
-2 signal can be used to switch valve v7.℃・0Also,
When the temperature or pressure of the water supplied to the reverse osmosis treatment equipment reaches the indicated value, the electrical signal from the temperature indication alarm meter TIA or the pressure indication alarm meter PIA causes the valve V3 to close and the valve V6 to open, causing the reverse osmosis treatment equipment supply water to flow in the reverse direction. It flows directly into the concentrated water circulation pipe 11 through the percolation treatment equipment supply water flow pipe 14 .

In this way, the cleaning wastewater supplied to the circulation tank 6 with a predetermined capacity provided downstream of the cleaning drainage tank 1 is transferred to the high-pressure pump 9.
The waste water is supplied to the reverse osmosis treatment device 10 via a water filter to separate the waste water into concentrated water and permeated water, and the concentrated water is sent to a cooler 1 through a water filter.
After passing through 2, the process of returning to circulation tank 6 is repeated for concentration.
Since the water level in the circulation tank 6 is detected by the LICA water level indicator and adjustment alarm meter and continues to be concentrated, a large amount of washing water can be efficiently processed. Concentrated water in 6 continues to be diluted by the washing wastewater supplied from the washing wastewater tank 1 until the water level in the circulation tank 6 becomes constant.
The quality of the permeated water from the reverse osmosis treatment device 10 does not deteriorate rapidly, and a large amount of high-quality permeated water can be obtained.

Furthermore, after the concentration ratio has increased several tens of times, valve v1 must be closed or the circulation tank pump 4 must be stopped by the electric signal from the flow rate integration indicator FMCIA, or the conductivity indicator alarm By closing the valve V1 in response to an electric signal from the CIA-1, the communication between the cleaning wastewater tank 1 and the circulation tank 6 is cut off, and the cleaning wastewater is then concentrated at a final concentration ratio of tens to hundreds of times at ℃. As a result, the concentration of concentrated water is rapidly increased, and therefore, final concentrated water with a final concentration factor of several tens to hundreds of times can be obtained very quickly and easily.

Furthermore, the concentration magnification can be set in advance by indicating the cumulative flow rate flowing through the circulation tank supply pipe 3 to the flow rate cumulative indicator and alarm meter FMCIA.

Furthermore, when the concentrated water reaches a predetermined final concentration magnification, the valve V5 is switched by the water level indication adjustment alarm meter LICA, so that the final concentrated water can be directly sent to the drum chambers by the piston flow action of the washing waste water. The process of packing the final concentrated water into drums becomes extremely easy.

Moreover, the start/stop of the circulation tank pump 4, the opening/closing of the valve 1, and the switching of the valve V5 are controlled by each alarm meter FMCIA and LICA.
Since the system is automatically operated by electric signals from the CIA-1, it is extremely easy to discharge the final concentrated water out of the system by the piston flow action of the washing waste water.

Furthermore, if the impurity content is high at the time of supply and cleaning wastewater is concentrated to a final concentration ratio of several hundred times, the impurity content in the final concentrated water will be extremely high. Even if there is a problem such as the water level indicator and adjustment alarm meter LICA not being able to adjust the indication, the electricity level indicator and alarm meter CI
By controlling the concentration according to A-1, the above problems can be prevented.

Furthermore, the temperature or pressure of the water supplied to the reverse osmosis treatment equipment is measured by the humidity indicator and alarm meter TIA or the pressure indicator and alarm meter PIA, and when the indicated value is reached, the valve V3 is closed by the electric signal from the alarm meters TIA and PIA, and the valve V6 is closed. By opening the reverse osmosis treatment apparatus supply water at an abnormal temperature or pressure to the branch pipe 14, the membrane surface of the reverse osmosis treatment apparatus 10 can be prevented from being exposed to abnormal temperature or pressure. It is extremely effective for maintenance.

In addition, reverse osmosis membranes generally have the property that as the impurity content of the water supplied to the reverse osmosis treatment device that comes into contact with the membrane surface increases, the temperature and amount of permeated water decrease.・Due to long-term use, the amount of permeated water decreases due to compaction of the membrane and dirt on the membrane surface. Utilizing the property of being proportional to pressure,
The above method can be carried out by measuring the pressure of the concentrated water with the pressure indicator controller PIC, or alternatively by measuring the flow rate of the permeated water with the flow indicator controller FIC and automatically adjusting the pressure of the concentrated water with the valve v4. By eliminating the drawbacks and keeping the amount of permeated water constant, the operating pressure within the reverse osmosis treatment device 10 is lowered to ensure a long life of the membrane.

On the other hand, in the step of obtaining the final concentrated water, the pressure of the concentrated water at the outlet of the reverse osmosis treatment device 10 is kept constant by the pressure control valve P.
By controlling the IC and valve v4, the flow rate of permeated water can be increased, thereby further increasing the concentration efficiency.

Furthermore, the quality of permeated water is relatively good until the concentration ratio is several tens of times, so it is treated as reuse water or discharge water from the recovered water supply pipe 20, but when the concentration ratio reaches a predetermined concentration ratio, the flow rate integration indicator etc. Therefore, cleaning drainage tank 1
When the communication between the circulation tank 6 and the reverse osmosis treatment device 1 is cut off,
The quality of the permeated water from 0 rapidly deteriorates, but at this time the valve v7 is switched by an electric signal from the flow rate integration indicator FMCIA, and the bad permeated water is cleaned and discharged from the permeated water return pipe 19;
Since the permeated water is returned to the water tank 1, it is appropriately classified according to its quality.

Therefore, it is possible to effectively obtain permeated water that can be reused or discharged, and the bad permeated water is returned to the cleaning wastewater tank 1 and then goes through the above concentration treatment process again, and a portion of the good quality permeated water is collected. This makes it extremely effective for water circulation.

The valve v7 can also be switched by measuring the conductivity of the permeated water with a conductivity indicator/alarm meter CIA-2 and switching based on the measured value.
Even if the electrical conductivity of the permeated water suddenly increases due to the destruction of the 0 membrane, the bad permeated water is returned to the cleaning drainage tank 1 by switching the valve V7, thereby preventing it from mixing with the good quality permeated water. I can do it.

Furthermore, when a home cleaning operation is required to remove dirt from the membrane surface of the reverse osmosis treatment device 10, the pressure at the outlet side of the high-pressure pump 9 can be automatically checked.

In other words, the amount of permeated water generally decreases as the membrane surface becomes fouled, but in this embodiment, the pressure on the outlet side of the high-pressure pump 9 is controlled in order to keep the amount of permeated water constant. If the specified amount of permeated water is not obtained even if the outlet side pressure is raised higher than usual, it can be automatically confirmed that ball cleaning is necessary.

In addition, a permeated water tank 1 is located near the reverse osmosis treatment device 10.
6 is installed, and the permeated water flows down into the permeated water tank 16 based on the head difference between the water levels of the reverse osmosis treatment device 10 and the permeated water tank 16, and the water level of the permeated water tank 16 is adjusted by the water level switch LS to the reverse osmosis treatment device 10. The permeated water pump 18 is started and stopped to automatically discharge the permeated water so that no pressure is applied to the membrane surface on the permeated water side of the reverse osmosis treatment device 10. Therefore, the pressure applied to the reverse osmosis treatment device 10 can be effectively used without pressure loss.

Furthermore, in this embodiment, since the electrical system lines as shown in FIG. 2 are wired at a temperature of 0.degree. C., each operation mode is automatically controlled and unmanned operation is therefore possible.

Figure 3 shows the concentration ratio (amount of wastewater to be treated/amount of concentrated water) obtained by repeating reverse osmosis treatment using the complete batch concentration method shown in Figure 1. ) and the radioactive material removal rate (radioactive material concentration in concentrated water/radioactive material concentration in permeated water), where the vertical axis represents the radioactive material removal rate and the horizontal axis represents the concentration ratio. The * mark in Figure 3 is 58CO.
, Mu marks indicate the results of reverse osmosis treatment of cleaning wastewater containing radioactive substances such as 60Co and 54Mn radioactive substances.

As shown in Figure 3, the removal rate of radioactive substances increases as the concentration ratio increases. Therefore, when treating wastewater containing radioactive substances as described above, reverse osmosis It can be seen that even if the concentration of the feed water increases, the quality of the permeated water does not deteriorate significantly.

Therefore, when the method according to the present invention is used for cleaning wastewater containing radioactive substances, it is applied as a more effective treatment method.

[Brief explanation of the drawing]

Figure 1 is a flowchart of reverse osmosis treatment of wastewater applied to the conventional complete batch concentration method, Figure 2 is a flowchart of an embodiment of the method of the present invention, and Figure 3 is the concentration ratio of cleaning wastewater containing radioactive materials. This shows the relationship with the removal rate of radioactive substances. 1...Washing drainage tank, 6...Circulation tank, 9...High pressure pump, 10...Reverse osmosis treatment device, 12-... Cooler.

Claims (1)

[Claims] 1. The wastewater to be treated is supplied to a circulation tank with a predetermined capacity provided downstream of the washing wastewater tank, and is supplied to a reverse osmosis treatment device via a high-pressure pump to separate the wastewater into concentrated water and permeated water. Concentration is carried out by repeating the process of passing the concentrated water through the cooler and then returning it to the circulation tank at °C. Until the concentration ratio is several tens of times, the wastewater is supplied from the wastewater tank to the circulation tank. A method for treating wastewater, characterized in that the water level of the wastewater tank is maintained at a constant level to continue concentration, and the communication between the wastewater tank and the circulation tank is cut off at .