JP6731515B1 - Wastewater treatment facility and wastewater treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wastewater treatment facility or the like which can obtain evaporated concentrated water which is less likely to cause a trouble when being transferred to a solid content generation unit and which can efficiently generate a precipitate in the solid content generation unit. That is the issue. SOLUTION: An evaporative concentration section for subjecting waste water to an evaporative concentration treatment to obtain an evaporative concentrated water and a solid content producing section for producing a solid content from the evaporative concentrated water are provided. The wastewater contains a dissolved component that becomes a precipitate by concentration, solids containing precipitates are generated in the solid content generation unit, and evaporation concentration is evaporated in the evaporation concentration unit. Provided is a wastewater treatment facility or the like in which the end time of the evaporative concentration treatment is determined by at least one of the specific gravity, water content, and conductivity of the evaporative concentration water being treated. [Selection diagram]

Description

TECHNICAL FIELD The present invention relates to wastewater treatment equipment and, for example, a wastewater treatment method implemented in the wastewater treatment equipment.

Conventionally, as a wastewater treatment facility, for example, organic waste is anaerobically treated to obtain sludge, and the wastewater that has undergone anaerobic treatment is subjected to membrane separation with a reverse osmosis membrane and then concentrated with a reverse osmosis membrane. There is known a facility configured to evaporate and concentrate both waste water and sludge (Patent Document 1).

In the waste water treatment facility described in Patent Document 1, the waste water membrane-concentrated by the reverse osmosis membrane and the evaporative concentrated water obtained by evaporating and condensing the sludge are dissolved in phosphate ions, magnesium ions, ammonium ions, or the like. Including ingredients. Although such a dissolved component exists in a dissolved state, it precipitates when the water content is further reduced and the concentration proceeds. The solid content containing the precipitate becomes a useful material that can be used in applications such as fertilizers, or can be discarded as an unnecessary material.

JP, 2005-192953, A

By the way, in the wastewater treatment facility described in Patent Document 1, the evaporative concentrated water after the evaporative concentrating treatment is transferred to the solid content generation unit to precipitate dissolved components contained in the evaporative concentrated water, and solids containing precipitates. It is possible to get a minute.
Here, the evaporative concentrated water that has been simply subjected to the evaporative concentrating treatment may be excessively concentrated or insufficiently concentrated. For example, the excessively concentrated evaporated concentrated water contains a relatively large amount of precipitates, so that the precipitates may cause troubles such as clogging of the transfer route during the transfer to the solid content generation unit. On the other hand, evaporative concentrated water that is insufficiently concentrated does not contain many precipitates, so it hardly causes the above problems at the time of transfer, but since the concentration of dissolved components in the evaporative concentrated water is low, it cannot be transferred. Precipitates cannot be efficiently generated in the solid content generating part.
As described above, it is difficult for the evaporated concentrated water simply concentrated by the evaporative concentration treatment to efficiently generate the precipitates in the solid content generation portion after the transfer while suppressing the troubles caused by the precipitates when the water is transferred. There is a problem that is.

In view of the above problems and the like, the present invention is a wastewater treatment facility and a wastewater treatment method capable of obtaining evaporative concentrated water that is less likely to cause trouble during transfer, and that efficiently produces precipitates after transfer. The challenge is to provide.

In order to solve the above problems, the wastewater treatment facility according to the present invention, an evaporative concentration section for performing evaporative concentration treatment on wastewater to obtain evaporative concentrated water,
A solid content generation unit for generating a solid content from the evaporated concentrated water,
The evaporation concentrated water is configured to be transferred from the evaporation concentration unit to the solid content generation unit,
The waste water contains a dissolved component that becomes a precipitate by concentration,
In the solid content generation unit, the solid content containing the precipitate is generated,
In the evaporative concentration section, the end time of the evaporative concentration processing is determined by at least one of the specific gravity, the water content, and the conductivity of the evaporative concentrated water on which the evaporative concentration processing is performed.

In the above wastewater treatment equipment, the end time of the evaporative concentration treatment is determined by using at least one of the specific gravity, water content, and conductivity of the evaporative concentrated water whose water content has been reduced and concentrated by the evaporative concentration treatment. It Such specific gravity, water content, or conductivity can be set by an experiment conducted in advance. By adopting a specific gravity, a water content, or a value close to the conductivity at which the precipitate theoretically begins to be generated in the evaporative concentrated water as the above-mentioned set value, the evaporative concentrated water after the evaporative concentration treatment may generate a precipitate. Although it is in a state, the stirring force at the time of transfer suppresses the generation of precipitates. Therefore, troubles such as clogging of the transfer path during transfer are unlikely to occur. Moreover, the specific gravity, the water content, or the evaporative concentrated water that has been evaporatively concentrated at the electrical conductivity is set, for example, by allowing it to stand still or cooling in the solid content generation section to efficiently precipitate dissolved components, A solid content containing a precipitate can be obtained.
Therefore, in the above wastewater treatment facility, it is possible to obtain evaporative concentrated water that is less likely to cause troubles when transferred to the solid content generating unit and that can efficiently generate a precipitate in the solid content generating unit. ..

In the above wastewater treatment facility, the evaporative concentration section may perform the evaporative concentration treatment until the deposits are generated in the evaporative concentrated water.
As a result, the evaporative concentrated water that has undergone the evaporative concentrating process is in a state where precipitates are generated. By transporting such evaporated concentrated water to the solid content generation unit and allowing it to stand or cool, a precipitate can be generated more efficiently. Moreover, as described above, the occurrence of precipitates in the evaporated concentrated water is suppressed by the stirring force at the time of transfer, and therefore troubles at the time of transfer are less likely to occur.

The wastewater treatment method of the present invention comprises an evaporative concentration step of subjecting wastewater to an evaporative concentration treatment to obtain evaporative concentrated water,
A solid content generation step of generating solid content from the evaporated concentrated water,
The evaporative concentrated water that has passed through the evaporative concentration step is transferred to perform the solid content generation step,
The waste water contains a dissolved component that becomes a precipitate by concentration,
In the solid content generation step, the solid content containing the precipitate is generated,
In the evaporative concentration step, the end time of the evaporative concentration processing is determined by at least one of the specific gravity, the water content and the conductivity of the evaporative concentrated water on which the evaporative concentration processing is performed.

The wastewater treatment method and the wastewater treatment facility of the present invention are evaporative concentrates that are less likely to cause troubles when transferred to a solid content generation unit, and are capable of efficiently forming precipitates in the transferred solid content generation unit. There is an effect that can be obtained.

The schematic diagram showing the outline of the wastewater treatment equipment of this embodiment.

Hereinafter, one embodiment of the wastewater treatment facility according to the present invention will be described in detail with reference to the drawings.

In the wastewater treatment facility 1 of the present embodiment, for example, as shown in FIG. 1, the wastewater A containing a dissolved component that becomes a precipitate due to a decrease in water content is subjected to an evaporative concentration process to obtain an evaporative concentrated water B. The unit 10 is provided.
The wastewater treatment facility 1 of the present embodiment further includes a solid content generation unit 20 that generates a solid content C containing a precipitate from the evaporated concentrated water B concentrated by the evaporation concentration processing.
The wastewater treatment facility 1 of the present embodiment is configured to transfer the evaporative concentrated water B, which has been subjected to the evaporative concentration processing, from the evaporative concentration section 10 to the solid content generation section 20.
In the evaporative concentration section 10 of the wastewater treatment facility 1 of the present embodiment, the end time of the evaporative concentration processing is determined by at least one of the specific gravity, water content, and conductivity of the evaporative concentrated water B on which the evaporative concentration processing is performed. Has a configuration.

The wastewater treatment facility 1 of the present embodiment has a wastewater supply path 30 that supplies the wastewater A to the evaporative concentration section 10. Further, an evaporation/concentration water transfer path 40 for sending the evaporation/concentration water B whose water content is reduced in the evaporation/concentration unit 10 to the solid content generation unit 20 is provided.
In addition, the wastewater treatment facility 1 of the present embodiment has a configuration in which the solid content C generated in the solid content generation unit 20 can be taken out. Further, the wastewater treatment facility 1 of the present embodiment has a liquid content take-out path 50 for taking out the stored solid content C and the separated liquid content D from the solid content generation unit 20.
Further, the wastewater treatment facility 1 of the present embodiment includes a hydrometer 70 that intermittently measures the specific gravity of the evaporated concentrated water B that has been subjected to the evaporative concentration processing in the evaporative concentration section 10. Further, a water content meter 80 for intermittently measuring the water content of the evaporatively concentrated water B that has been evaporatively concentrated in the evaporative concentration section 10 is provided. A conductivity meter (not shown) that intermittently measures the conductivity of the evaporative concentrated water B that has been evaporatively concentrated in the evaporative concentration section 10 may be provided.

The wastewater treatment facility 1 of the present embodiment has a configuration for condensing the water vapor evaporated in the evaporative concentration section 10. The condensed water becomes condensed water E.
The wastewater treatment facility 1 of the present embodiment includes a first pump 61 for supplying the wastewater A to the evaporative concentration section 10 and a second pump for sending the evaporative concentrated water B of the evaporative concentration section 10 to the solid content generation section 20. It has 62 and the 3rd pump 63 for taking out the liquid content D of the solid content production|generation part 20 from the solid content production|generation part 20. As these pumps, commercially available products can be used.

The wastewater treatment facility 1 of the present embodiment transfers at least a part of the evaporative concentrated water B, which has been subjected to the evaporative concentration processing in the evaporative concentration section 10, to the solid content generation section 20, and the solid content generation section 20 removes the solid content C. It may be a batch-type equipment for precipitation.
On the other hand, the wastewater treatment equipment 1 of the present embodiment is a semi-batch type (semi-continuous type) in which the evaporative concentration water in the evaporative concentration section 10 is intermittently transferred to the solid content generation section 20 while performing the evaporative concentration processing in the evaporative concentration section 10. Equation) equipment.
Further, the wastewater treatment equipment 1 of the present embodiment is a continuous equipment for continuously transferring the evaporative concentrated water B of the evaporative concentration section 10 to the solid content generation section 20 while performing the evaporative concentration processing in the evaporative concentration section 10. May be.

The wastewater A supplied to the evaporative concentration section 10 is not particularly limited, and for example, an inorganic wastewater containing an inorganic acid or an inorganic alkali, an organic wastewater containing a relatively large amount of organic matter, or the like is adopted. Specifically, factory wastewater discharged from an electronic component manufacturing factory that manufactures liquid crystal panels and the like is used.
Such wastewater A may be, for example, wastewater that has undergone a biological treatment such as an activated sludge method or a methane fermentation treatment. Then, the waste water further concentrated by membrane separation by a reverse osmosis membrane (membrane separation concentrated waste water) may be used.

The wastewater A supplied to the evaporative concentration section 10 contains various dissolved components. The dissolved component is a component that is in a dissolved state in the wastewater A, but the dissolved state cannot be maintained due to the decrease in water content and can be deposited. The dissolved component may be deposited due to a change in temperature, stoppage of flow, etc., and may be a deposit.

Examples of soluble components include inorganic ions and water-soluble organic substances.
Examples of the inorganic ion include sodium ion, potassium ion, magnesium ion, ammonium ion, sulfate ion, phosphate ion, nitrate ion, chloride ion, fluorine ion, and borate ion.
Examples of water-soluble organic substances include isopropyl alcohol (IPA) and dimethyl sulfoxide.

Examples of the precipitate include sodium sulfate, magnesium ammonium phosphate, sodium borate and the like.

The sodium ion content of the wastewater A is preferably at least 0.1% by mass. Further, the content of sulfate ions is preferably at least 0.05% by mass. As a result, the amount of sodium sulfate contained in the precipitate is increased, and there is an advantage that the precipitate can be used as a useful substance. The content of sodium ions and sulfate ions is usually less than 5 mass% in terms of sodium sulfate.

Further, the calcium content of the wastewater A is preferably 100 mg/L or less. As a result, it is possible to suppress the solid content C containing the precipitate from becoming hard rock. When the solid content C is not in the form of hard rock and is in the form of, for example, a slurry, the handleability of the solid content C is improved, and thus the solid content C containing precipitates can be taken out more efficiently.
For the same reason as above, the magnesium content of the wastewater A is preferably 100 mg/L or less.

The total organic carbon amount (TOC amount) of the wastewater A is preferably 100 mg/L or less. Thereby, the purity of the precipitate used when reusing the solid content C can be further increased. Further, it is possible to suppress the coloring of the solid content C derived from an organic substance.

The evaporative concentration section 10 has a vaporization tank 11. In the evaporative concentration section 10, the water in the wastewater A is evaporated while the wastewater A is stored inside the vaporization tank 11. Specifically, water is evaporated while the wastewater A is made to flow in the tank. Even if the specific gravity, the water content, or the conductivity of the evaporated concentrated water B reaches the specific gravity, the water content, or the conductivity with which precipitates can be deposited, the evaporated concentrated water B is still flowing, so In part 10, the precipitation of precipitates is suppressed.

The wastewater treatment facility 1 of the present embodiment determines the end time of the evaporative concentration processing based on at least one of the specific gravity, water content, and conductivity of the evaporative concentrated water B on which the evaporative concentration processing is performed. It is configured. The specific gravity of the evaporated concentrated water B that has been subjected to the evaporative concentration treatment can be measured by the hydrometer 70. The water content of the evaporative concentrated water B which has been subjected to the evaporative concentration treatment can be measured by a water content meter 80. Then, the evaporative concentrated water B that has been subjected to the evaporative concentration processing is configured to be transferred from the evaporative concentration section 10 to the solid content generation section 20.
In the evaporative concentration section 10 of the wastewater treatment facility 1 of the present embodiment, the evaporative concentration processing may be performed until a precipitate is generated in the evaporative concentrated water B.

In the waste water treatment facility 1 described above, one specific gravity, one water content, or one conductivity is set in order to determine the end time of the evaporative concentration treatment. Two or more of specific gravity, water content and conductivity may be set respectively. When setting the above-mentioned specific gravity, water content, and electric conductivity, values close to the specific gravity, water content, and electric conductivity at which precipitates theoretically start to occur in the evaporated concentrated water B are adopted as the above-mentioned set values. As a result, although the evaporative concentrated water B that has been subjected to the evaporative concentration treatment is in a state where a precipitate can be generated, the stirring force at the time of transfer suppresses the generation of a precipitate. Therefore, troubles such as clogging of the transfer path during transfer are unlikely to occur. Moreover, the dissolved component is efficiently precipitated by, for example, leaving the evaporative concentrated water B, which has been evaporatively concentrated with the set specific gravity, water content, or conductivity, in the solid content generation unit 20 for cooling. Then, the solid content C containing the precipitate can be obtained.
Therefore, in the wastewater treatment facility 1, the evaporated concentrated water B is less likely to cause a trouble when being transferred to the solid content generation unit 20, and the evaporated concentrated water B is capable of efficiently forming a precipitate in the solid content generation unit 20. Can be obtained.

As the set values of the specific gravity, the water content, and the conductivity, it is preferable to adopt values close to the specific gravity, the water content, and the conductivity at which the precipitate theoretically begins to be generated in the evaporated concentrated water B, and the precipitate is theoretically It is more preferable to adopt a set value that occurs slightly. Such specific gravity, water content, and conductivity can be set by experiments conducted in advance.

The evaporative concentration section 10 includes a thermometer (not shown) that measures the temperature of the evaporative concentrated water B that has been subjected to the evaporative concentration processing, and a pressure gauge (not shown) that measures the pressure during the evaporative concentration processing. It is preferable to have. Thereby, the pressure in the evaporative concentration processing and the temperature of the evaporative concentrated water B can be measured. By obtaining the above-mentioned set values for each temperature condition and pressure condition in advance, it is possible to adopt each set value for each measured temperature and pressure. By adopting each set value in this way, the reliability of the set value for ending the evaporative concentration process becomes higher.

For example, the wastewater treatment facility 1 of the present embodiment ends the evaporative concentration processing when the specific gravity of the evaporative concentrated water B in the evaporative concentration section 10 reaches a specific gravity set value (up to a specific gravity set value). It is preferable to have a configuration.
The specific gravity setting value is obtained by a preliminary experiment conducted in advance. Specifically, the specific gravity (theoretical specific gravity value) when a precipitate is generated while concentrating the evaporative concentrated water B under the same conditions (drainage, temperature, pressure, etc.) as the evaporative concentration processing performed in the evaporative concentration section 10. taking measurement.
It is preferable that the specific gravity set value is one value of 0.9 times or more and 1.5 times or less, and one value of 0.9 times or more and 1.3 times or less of the theoretical specific gravity value. Is more preferable, and it is even more preferable that the value is one more than 1.0 times and 1.2 times or less.
When the specific gravity set value is one value equal to or more than 0.9 times the theoretical specific gravity value, it is possible to more efficiently generate a precipitate in the evaporated concentrated water B transferred to the solid content generation unit 20. it can.
Since the specific gravity set value is one value equal to or less than 1.5 times the theoretical specific gravity value, the precipitates that may be contained in the evaporated concentrated water B transferred to the solid content generation unit 20 may be included in the evaporated concentrated water transfer path. Trouble such as clogging the inside of 40 can be further suppressed.
More specifically, the specific gravity of a set value, for example 1.05 g / cm ³ or more 1.50 g / cm ³ or less, preferably 1 numbers in the range of 1.175g / cm ³ or more 1.375 g / cm ³ or less Can be adopted.

For example, the wastewater treatment facility 1 of this embodiment is configured to determine the end time of the evaporative concentration processing based on the conductivity of the evaporative concentrated water B on which the evaporative concentration processing is being performed. The conductivity of the evaporated concentrated water B that has been subjected to the evaporative concentration treatment can be measured by a conductivity meter (not shown).
The wastewater treatment facility 1 of the present embodiment performs the evaporative concentration processing when the electric conductivity of the evaporative concentrated water B in the evaporative concentration section 10 reaches a specific conductivity set value (increases to a specific conductivity set value). It may have a configuration to end. In this case, the conductivity set value can be obtained in the same manner as the specific gravity set value described above, and the conductivity set value is a value based on the theoretical conductivity value (a value similar to a multiple value for the theoretical specific gravity value described above). ) Is preferable.

Further, for example, in the wastewater treatment equipment 1 of the present embodiment, when the water content of the evaporative concentrated water B in the evaporative concentration section 10 reaches a specific water content set value (decreases to a specific water content set value), It is preferable to have a configuration for ending the evaporative concentration treatment.
The water content setting value is obtained by preliminary experiments conducted in advance. Specifically, while evaporating and concentrating water B is concentrated under the same conditions (drainage, temperature, pressure, etc.) as the evaporating and concentrating process performed in the evaporative concentrating unit 10, the water content (theoretical water content value) when a precipitate is formed. ) Is measured.
The above-mentioned water content setting value is preferably one value of 0.7 times or more and 1.3 times or less of the above theoretical water content value, and one value of 0.8 times or more and 1.2 times or less. It is more preferable that the value is 0.9 times or more and less than 1.0 times.
When the above-mentioned water content set value is one value equal to or more than 0.7 times the theoretical water content value, the precipitates that may be contained in the evaporative concentrated water B transferred to the solid content producing unit 20 are the evaporative concentrated water. Trouble such as clogging the inside of the transfer path 40 can be further suppressed.
Since the above-mentioned water content set value is one value equal to or less than 1.3 times the theoretical water content value, the evaporative concentrated water B transferred to the solid content producing section 20 produces precipitates more efficiently. be able to.
More specifically, as the water content set value, for example, one numerical value in the range of 30% or more and 95% or less can be adopted.

The evaporative concentration section 10 is configured to evaporate water while circulating the evaporative concentrated water B inside. Specifically, the evaporative concentration section 10 has a circulation path 12 for circulating the evaporative concentrated water B therein, and causes the evaporative concentrated water B to circulate in the vaporization tank 11 while evaporating water.

The evaporative concentration section 10 evaporates water by heating the wastewater A (evaporated concentrated water B) to a predetermined treatment temperature under reduced pressure, for example. The reduced pressure condition is, for example, 20 hPa or more and 45 hPa or less, and the treatment temperature is, for example, 50° C. or more and 85° C. or less.
In addition, by adding a scale inhibitor to the wastewater A, the solid content C may be prevented from being excessively generated in the evaporative concentration section 10.

Moisture that has once been vaporized in the evaporative concentration section 10 is condensed at room temperature under atmospheric pressure conditions to become condensed water E. The condensed water E is used as equipment water in a factory, for example.

The evaporative concentrated water transfer path 40 is a path for transferring the evaporative concentrated water B from the evaporative concentrating section 10 to the solid content generating section 20. For example, as shown in FIG. 1, the evaporative concentrated water transfer path 40 shares a path with a part of the circulation path 12 from the outlet of the evaporative concentrated water B in the evaporative concentration section 10 to the branch. The evaporative concentrated water transfer path 40 is usually constituted by a pipe.

In the evaporated concentrated water transfer path 40, the evaporated concentrated water B is subjected to a stirring force when being transferred. Therefore, even if the temperature at the time of transfer is lower than the temperature at the time of evaporative concentration treatment, the specific gravity, water content, or conductivity of the evaporative concentrated water B to be transferred is theoretically such that precipitates are generated as described above. Even if it is a theoretical value, the generation of precipitates is suppressed by the stirring force.

The wastewater treatment facility 1 of the present embodiment has an evaporated concentrated water transfer path 40 and a second pump 62 arranged in a shared portion of the circulation path 12 described above. By the second pump 62 and the circulation path 12 described above, the evaporative concentrated water B in the evaporative concentrating unit 10 can be circulated. Further, the evaporative concentrated water B can be transferred to the solid content generation unit 20 by the second pump 62 and the evaporative concentrated water transfer path 40.

The wastewater treatment facility 1 of the present embodiment has valves installed on the downstream sides of the branches of the circulation path 12 and the evaporative concentrated water transfer path 40, and the evaporation is performed by each operation of the plurality of valves. It has a configuration in which the wastewater A of the concentrating unit 10 can be circulated and the evaporated concentrated water B from the evaporative concentrating unit 10 can be transferred to the solid content generating unit 20. The second pump 62 is attached to the upstream side of the valves (portion sharing the path).

The solid content generation unit 20 has a precipitation settling tank 21. The solid content generation unit 20 has a configuration that precipitates the generated solid content C in the tank of the precipitation settling tank 21.

In the solid content generation unit 20, the evaporated concentrated water B transferred from the evaporation concentration unit 10 is left standing. When the evaporated concentrated water B is allowed to stand, the solid content C containing the precipitate is precipitated and stored in the bottom of the precipitation settling tank 21.
The temperature condition of the evaporated concentrated water B in the solid content generation unit 20 is preferably 10° C. or more lower than the temperature condition of the evaporated concentrated water B in the evaporation concentration unit 10. By setting the temperature condition to be lower than 10° C., the generation of precipitates is further promoted, and the precipitation of the solid content C can be further promoted. The difference in such temperature conditions is usually 80° C. or less.

The solid content C precipitated in the solid content generation unit 20 can become a crystalline solid. It can also be pasty.
The solid content C stored in the bottom of the deposition/precipitation tank 21 is taken out of the tank by an operator (manpower) after the liquid content D is taken out of the tank. The liquid component D is taken out of the tank by, for example, a tank truck equipped with a suction pump.

In the wastewater treatment facility 1 of the present embodiment, the solidified content C including the precipitate is precipitated by allowing the solidified-evaporated water B, which has been evaporated and concentrated in the solidified and concentrated section 10, to stand still in the solid content generation section 20. Alternatively, by lowering the temperature condition of the evaporative concentrated water B in the solid content generation unit 20 to be lower than the temperature condition of the evaporative concentration processing in the evaporative concentration unit 10, the solid content C containing the precipitate is precipitated. This makes it possible to efficiently obtain a solid content C containing a precipitate that becomes a useful material in various applications or is discarded as an unnecessary material. Since the solid content C is separated from the liquid content D and stored below, the solid content C can be easily collected.

In the wastewater treatment facility 1 of the present embodiment, the evaporated concentrated water B that has passed through the evaporated concentrated water transfer path 40 is transferred to the solid content generation unit 20 (precipitation precipitation tank 21) in the upper portion of the precipitation settling tank 21 of the solid content generation unit 20. It is preferable to have an inflow configuration. Further, it is more preferable to have a configuration in which the evaporated concentrated water B that has passed through the evaporated concentrated water transfer path 40 flows into the solid content generation unit 20 (precipitation precipitation tank 21) from above the liquid surface in the precipitation settling tank 21.
With such a configuration, it is possible to prevent the solid content C stored below from being dispersed in the liquid content D due to the inflow of the evaporated concentrated water B.

The wastewater treatment facility 1 of this embodiment has a configuration capable of backwashing the evaporated concentrated water transfer path 40. Specifically, the pressurized water is supplied in the reverse direction from the middle of the evaporative concentrated water transfer path 40 (indicated by G in FIG. 1), and the discharge pipe arranged on the upstream side (evaporative concentrating section 10 side) of the supply portion is connected. It is discharged to the outside via the route (shown by H in FIG. 1). With such a configuration, it is possible to wash away dirt and the like adhering to the inside of the piping of the evaporated concentrated water transfer path 40. Examples of the dirt attached to the inside of the pipe include a small amount of precipitate generated in the evaporated concentrated water B.

The solid content generation unit 20 has a stirring path 22 for stirring the liquid content D after the solid content C is precipitated. The stirring path 22 is arranged outside the precipitation settling tank 21. The stirring path 22 has a configuration that raises the liquid content D taken out from the solid content generation unit 20 and supplies the liquid content D into the tank of the precipitation settling tank 21 from a position higher than the take-out position. The stirring path 22 is usually composed of piping.
With the stirring path 22 having such a configuration, the liquid component D in the precipitation tank 21 can be circulated and stirred. As a result, the liquid component D can be brought close to a uniform liquid. Then, the liquid content D approaching a uniform liquid can be taken out from the solid content production section 20 through the liquid content take-out path 50.

It is preferable that the solid content generation unit 20 has a configuration in which the liquid content D that has passed through the stirring path 22 flows into the solid content generation unit 20 in the horizontal direction or in the upward direction relative to the horizontal direction.
With such a configuration, it is possible to prevent the solid content C accumulated below from being dispersed in the liquid content D by the liquid flow of the inflowing liquid content D.

As shown in FIG. 1, in the wastewater treatment facility 1 of the present embodiment, the liquid content withdrawal path 50 is a part of the agitation path 22 from the outlet of the evaporated concentrated water B in the solid content generation section 20 to the branch, and the path. To share. Valves are attached to the stirring path 22 and the liquid extraction path 50, respectively, on the downstream side of the branch. The operation of stirring the liquid component D in the precipitation-precipitation tank 21 and the operation of discharging the liquid component D from the precipitation-precipitation tank 21 can be switched by each operation of the plurality of valves. A third pump 63 for taking out the liquid content D from the solid content generation unit 20 is attached to the upstream side of the valves (portion sharing the route).

In the solid content generation unit 20, the position for taking out the liquid content D in the stirring path 22 is higher than the highest position of the solid content C precipitated in the solid content generation unit 20 (above).
With such a configuration, it is possible to prevent the solid content C from accidentally entering the stirring path 22. When the solid content C enters, it causes clogging of the stirring path 22, but such clogging can be suppressed.

In the wastewater treatment facility 1 of the present embodiment, a turbo pump such as a centrifugal pump or a reciprocating pump such as a diaphragm pump is used as the third pump 63 attached in the middle of the stirring path 22 and the liquid extraction path 50. it can.
The third pump 63 is preferably a spiral pump of an external water injection type seal system rather than a magnet pump or the like. Since such a pump has a water injection structure, it hardly breaks down due to fine solid substances contained in the liquid D.

The precipitation settling tank 21 of the solid content generation unit 20 has, for example, an internal space height that an operator puts inside in a standing position. Further, the precipitation settling tank 21 has, for example, an internal volume that an operator puts inside in a standing position.
In the precipitation settling tank 21 in which most of the liquid content D has been discharged as described above, the operator enters the internal space and crushes the solid content C at the bottom that has settled to reduce it, and the operator precipitates the crushed solid content C. It can be carried out of the settling tank 21.

The above-mentioned precipitated solid content C contains a precipitate in which dissolved components have been precipitated. When the deposit is sodium sulfate, the deposit can be used as a useful substance in applications such as a bath agent, a desiccant, a glass manufacturing process, a pulp manufacturing process, and a detergent auxiliary agent. The solid content C is preferably used after being purified.
On the other hand, when the precipitate is not a useful substance, the precipitated solid content C can be discarded.

On the other hand, the liquid content D other than the solid content C precipitated in the solid content generation unit 20 will be discarded, for example. Alternatively, for example, a biological treatment or a coagulating sedimentation treatment can be applied to the liquid component D. The liquid component D may include a minute solid component C that floats without being precipitated.

After the solid content C and the liquid content D are taken out from the precipitation settling tank 21 of the solid content generation unit 20, the residual solid content C attached to the inner wall of the tank can be removed by a cleaning process. As the cleaning treatment, high-pressure water cleaning or the like can be adopted.

Next, an embodiment of the wastewater treatment method according to the present invention will be described.

The wastewater treatment method of this embodiment is
An evaporative concentration step of subjecting the wastewater to an evaporative concentration treatment to obtain an evaporative concentrated water B;
A solid content producing step of producing a solid content C from the evaporated concentrated water B,
The evaporative concentrated water B that has passed through the evaporative concentration step is transferred to carry out the solid content generation step,
Wastewater A contains a dissolved component that becomes a precipitate by concentration,
In the solid content generation step, solid content C containing a precipitate is generated,
In the evaporative concentration step, the end time of the evaporative concentration processing is determined by at least one of the specific gravity, the water content, and the conductivity of the evaporative concentrated water B that has been subjected to the evaporative concentration processing.

In the wastewater treatment method of the present embodiment, at the end of the evaporative concentration process, at least one of the specific gravity, the water content, and the conductivity of the evaporative concentrated water B concentrated by reducing the water content by the evaporative concentration process is used as an index. To decide. Such specific gravity, water content, or conductivity can be set by an experiment conducted in advance. By adopting a value close to the specific gravity, the water content, or the conductivity at which the precipitate theoretically begins to occur in the evaporated concentrated water B as the above-mentioned set value, the evaporated concentrated water B after the evaporative concentration treatment finishes the precipitate. Although it is in a state that can occur, the stirring force during transfer suppresses the generation of precipitates. Therefore, troubles such as clogging of the transfer path during transfer are unlikely to occur. Moreover, the evaporatively concentrated water B, which has been evaporatively concentrated at the set specific gravity, water content, or conductivity, is allowed to efficiently precipitate the dissolved components by, for example, allowing the evaporative concentrated water B to stand or cool after the transfer. It is possible to obtain a solid content C containing.
Therefore, in the above-mentioned wastewater treatment method, it is possible to obtain the evaporated concentrated water B which is less likely to cause a trouble at the time of transfer and which can efficiently generate the precipitate after the transfer.

Specifically, the wastewater treatment method of the present embodiment has a set value determination step of determining each set value of specific gravity, water content, or conductivity of the evaporative concentrated water B when the evaporative concentration processing is finished, and the evaporative concentration step described above. And an evaporation/concentration water transfer step of transferring the evaporation/concentration water B that has undergone the evaporation/concentration process from the evaporation/concentration section 10 to the solid content generation section 20, and the above solid content generation step.

The wastewater treatment method of this embodiment can be carried out as described above using the wastewater treatment facility 1 described above, for example.

In the wastewater treatment method of the present embodiment, the solid content generation step may be performed on at least a part of the evaporated concentrated water B that has undergone the evaporative concentration step, and a part of the evaporated concentrated water B that has undergone the evaporative concentration step may be intermittent. The solid content generation step may be carried out while replenishing the material. Moreover, you may implement a solid content formation process, supplying a part of evaporation concentrated water B which passed the evaporation concentration process continuously.
The evaporative concentration step, the evaporative concentrated water transfer step, and the solid content generation step may be performed at the same time or separately (for example, alternately).
The set value determination step is preferably performed before the evaporative concentration step. The evaporative concentrated water transfer step is preferably performed after the set value determination step.

In the set value determination step, as a set value of the specific gravity, water content, or conductivity of the evaporative concentrated water B when the evaporative concentration treatment is finished, it is theoretically preferable to adopt a set value at which a precipitate is generated. It is more preferable to adopt a set value at which a slight amount of precipitate is generated.
Each of the above set values is preferably a set value at a predetermined temperature and a predetermined pressure measured in the evaporative concentration process. Specifically, the above-mentioned set values are preferably determined for each temperature and pressure of the evaporative concentrated water B under the conditions of the evaporative concentrating treatment, and the specific gravity and water content of the evaporative concentrated water B are previously set. , Or by measuring the conductivity for each temperature and each pressure.

In the set value determination step, for example, the specific gravity set value of the evaporated concentrated water B when the evaporative concentration process is finished is determined.
The specific gravity set value is obtained by a preliminary experiment conducted in advance (before the evaporative concentration step). Specifically, the specific gravity (theoretical specific gravity value) when a precipitate is generated while concentrating the evaporative concentrated water B under the same conditions (drainage, temperature, pressure, etc.) as the evaporative concentration processing performed in the evaporative concentration section 10. taking measurement.
It is preferable that the specific gravity set value is one value of 0.9 times or more and 1.5 times or less, and one value of 0.9 times or more and 1.3 times or less of the theoretical specific gravity value. Is more preferable, and it is even more preferable that the value is one more than 1.0 times and 1.2 times or less.
When the specific gravity set value is one value equal to or more than 0.9 times the theoretical specific gravity value, it is possible to more efficiently generate a precipitate in the evaporated concentrated water B transferred to the solid content generation unit 20. it can.
Since the specific gravity set value is one value equal to or less than 1.5 times the theoretical specific gravity value, the precipitates that may be contained in the evaporated concentrated water B transferred to the solid content generation unit 20 may be included in the evaporated concentrated water transfer path. Trouble such as clogging the inside of 40 can be further suppressed.
More specifically, as the specific gravity set value, for example, one numerical value in the range of 1.175 g/cm ³ or more and 1.375 g/cm ³ or less can be adopted.

Further, in the set value determination step, for example, the water content set value of the evaporated concentrated water B at the time of ending the evaporation concentration process is determined.
The water content set value is obtained by a preliminary experiment conducted in advance (before the evaporative concentration step). Specifically, while evaporating and concentrating water B is concentrated under the same conditions (drainage, temperature, pressure, etc.) as the evaporating and concentrating process performed in the evaporative concentrating unit 10, the water content (theoretical water content value) when a precipitate is formed ) Is measured.
The above-mentioned water content setting value is preferably one value of 0.7 times or more and 1.3 times or less of the above theoretical water content value, and one value of 0.8 times or more and 1.2 times or less. It is more preferable that the value is 0.9 times or more and less than 1.0 times. In addition, the numerical values of these multiples are not the water content expressed as a percentage, but the values expressed based on 1 part by mass of the evaporated concentrated water B.
When the above-mentioned water content set value is one value equal to or more than 0.7 times the theoretical water content value, the precipitates that may be contained in the evaporative concentrated water B transferred to the solid content producing unit 20 are the evaporative concentrated water. Trouble such as clogging the inside of the transfer path 40 can be further suppressed.
Since the above-mentioned water content set value is one value equal to or less than 1.3 times the theoretical water content value, the evaporative concentrated water B transferred to the solid content producing section 20 produces precipitates more efficiently. be able to.
More specifically, as the water content set value, for example, one numerical value in the range of 30% or more and 95% or less can be adopted.

In the setting value determining step, the conductivity setting value of the evaporated concentrated water B when the evaporation concentration process is terminated may be determined. In this case, the conductivity set value is set based on the theoretical conductivity value in the same manner as the specific gravity set value described above.

In the evaporative concentration step, for example, the circulation route 12 is used to evaporate water by stirring the wastewater A under a reduced pressure condition of 20 hPa or more and 45 hPa or less and a temperature condition of 50° C. or more and 85° C. or less. To reduce the wastewater A and concentrate the wastewater A.
In the evaporative concentration step, both heating and depressurization are not necessarily required, and evaporation of water may be performed by either one.

In the evaporative concentration step, the step is terminated when at least one of the specific gravity, the water content, and the conductivity of the evaporative concentrated water B reaches the set value.
For example, in the evaporative concentration step, the specific gravity of the evaporative concentrated water B may be measured with a hydrometer 70 at intervals, and the step may be continued while the specific gravity increases to the specific gravity set value.
For example, in the evaporative concentration step, the water content of the evaporative concentrated water B is measured with a water content meter 80 at intervals, and the step is continued while the water content falls to the above water content set value. Good.
For example, in the evaporative concentration step, the electric conductivity of the evaporative concentrated water B is measured with a conductivity meter at intervals, and the step is continued while the electric conductivity rises to the electric conductivity set value. Good.
In the evaporative concentration step, it is preferable that the evaporative concentration treatment is performed until a precipitate is formed in the evaporative concentrated water B.
The evaporative concentration step may be terminated after a predetermined time has elapsed.

In the evaporative concentration step, the pH of the evaporative concentrated water B may be adjusted to 7.0 or more and 12.5 or less while evaporating the water. The pH of the evaporated concentrated water B can be adjusted, for example, by adding an alkaline agent such as potassium hydroxide or an acid such as hydrochloric acid.

In the evaporative concentrated water transfer step, the evaporative concentrated water B that has undergone the evaporative concentrated step is sent to the evaporative concentrated water transfer path 40 and further transferred to the solid content generation unit 20 by opening and closing the plurality of valves, for example.
In the evaporative concentrated water transfer step, the evaporative concentrated water B transferred through the evaporative concentrated water transfer path 40 receives a stirring force. Therefore, even if the temperature at the time of transfer is lower than the temperature at the time of evaporative concentration treatment, the theoretical value of the specific gravity, water content or conductivity of the evaporative concentrated water B to be transferred is theoretically the same as that of the above-mentioned theory. Even if it is a value, generation of precipitates is suppressed by the stirring force.

In the solid content producing step, the transferred evaporated concentrated water B is allowed to stand in the solid content producing unit 20. In the solid content producing step, the temperature condition of the evaporative concentrated water B is preferably lower than the treatment temperature condition in the evaporative concentrating step, and more preferably 10° C. or more. The difference in such temperature conditions is usually 80° C. or less.

In the solid content producing step, the period in which the evaporated concentrated water B is allowed to stand is, for example, 1 day or more and 30 days or less.

In the solid content generation step, it is preferable that the steam F generated in the precipitation settling tank 21 be discharged to the outside air by a vent valve or the like.

The wastewater treatment method of the present embodiment further includes an extraction step of extracting the solid content C precipitated in the solid content generation step and the liquid content D other than the solid content.

In the extraction step, for example, the solid content C is extracted after the liquid content D is extracted from the solid content generation unit 20.
Specifically, first, the liquid content D is approximated to a uniform liquid by stirring the liquid content D using the above-mentioned stirring path 22. The liquid content D that has approached the uniform content is taken out from the solid content production section 20 through the liquid content taking-out path 50. Next, an operator enters the precipitation settling tank 21 of the solid content generation unit 20, the solid content C stored at the bottom is crushed as necessary, and the solid content C is taken out by the operator from the solid content generation unit 20. For example, in this way, the solid content C and the liquid content D are respectively taken out.

The solid content C thus taken out is used for various purposes or discarded as described above. The liquid component D is, for example, discarded as described above.
As the precipitate is contained in the solid content C, the inorganic ions and the like contained in the liquid content D are reduced. Even when the solid content C is used for various purposes, or even when the solid content C is disposed of, the solid content C is efficiently used as much as the precipitates are generated in the solid content C. Or it can be disposed of. On the other hand, since the amount of inorganic ions and the like in the liquid component D is small, the load at the time of discarding is reduced, and the liquid component D can be efficiently disposed of.

The wastewater treatment facility and the wastewater treatment method of the above-described embodiment are as described above, but the present invention is not limited to the wastewater treatment facility and the wastewater treatment method described above.
Further, various modes used in general wastewater treatment facilities and wastewater treatment methods can be adopted within a range that does not impair the effects of the present invention.

1: Wastewater treatment facility,
10: Evaporative Concentration Section, 11: Vaporization Tank, 12: Circulation Route,
20: Solid content generation part, 21: Precipitation settling tank, 22: Stirring path,
30: Wastewater supply route,
40: Evaporative concentrated water transfer route,
50: liquid extraction path,
61: 1st pump, 62: 2nd pump, 63: 3rd pump,
70: hydrometer,
80: Water content meter,
A: waste water, B: evaporated concentrated water, C: solid content, D: liquid content, E: condensed water, F: steam.

Claims (4)

An evaporative concentration section that performs evaporative concentration processing on wastewater to obtain evaporative concentrated water,
A solid content generation unit for generating a solid content from the evaporated concentrated water,
The evaporation concentrated water is configured to be transferred from the evaporation concentration unit to the solid content generation unit,
The waste water contains a dissolved component that becomes a precipitate by concentration,
The solid content generation unit,
A precipitation settling tank for storing the solid content containing the precipitate generated from the transferred concentrated evaporated water at the bottom,
A stirring path for stirring by circulating the liquid content separated from the solid content by being stored in the bottom of the precipitation settling tank,
Wastewater treatment equipment having at least one configuration of the following (1) to (3).
(1)
A configuration in which the end time of the evaporative concentration processing is determined by the specific gravity of the evaporative concentrated water on which the evaporative concentration processing is performed,
When the specific gravity of the evaporated concentrated water rises to a specific gravity set value of 0.9 times or more and 1.5 times or less of a theoretical specific gravity value at which the precipitate theoretically starts to occur in the evaporation concentration section, the evaporation A configuration that ends the concentration process,
(2)
A configuration in which the end time of the evaporative concentration processing is determined by the water content of the evaporative concentrated water on which the evaporative concentration processing is performed,
When the water content of the evaporative concentrated water decreases to one water content set value of 0.7 times or more and 1.3 times or less of the theoretical water content value at which the precipitate theoretically starts to occur in the evaporative concentration section. A configuration for ending the evaporative concentration processing,
(3)
A configuration in which the end time of the evaporative concentration processing is determined by the conductivity of the evaporative concentrated water on which the evaporative concentration processing is performed,
When the conductivity of the evaporated concentrated water rises to one conductivity set value of 0.9 times or more and 1.5 times or less of the theoretical conductivity value at which the precipitate theoretically begins to occur in the evaporation concentration part A configuration for ending the evaporative concentration processing. The wastewater treatment facility according to claim 1 , wherein the deposition/sedimentation tank has an internal volume that allows a worker to take out the solid content therein. An evaporative concentration step of subjecting wastewater to an evaporative concentration process to obtain evaporative concentrated water;
A solid content generation step of generating solid content from the evaporated concentrated water,
The evaporative concentrated water that has passed through the evaporative concentration step is transferred to perform the solid content generation step,
The waste water contains a dissolved component that becomes a precipitate by concentration,
Further comprising a set value determining step of determining each set value of the specific gravity of the evaporated concentrated water, the water content, or the conductivity when the evaporative concentration processing is terminated,
At least one of the specific gravity of the evaporative concentrated water, the water content, or the conductivity, when the respective set value is reached, the evaporative concentration process is terminated,
At least one of the following (A), (B), and (C) is adopted ,
(A)
The end time of the evaporative concentration processing is determined by the specific gravity of the evaporative concentrated water on which the evaporative concentration processing is performed,
When the specific gravity of the evaporative concentrated water rises to a specific gravity set value of 0.9 times or more and 1.5 times or less of the theoretical specific gravity value at which the precipitate theoretically starts to be generated, the evaporative concentration processing is terminated. ;
(B)
The end of the evaporative concentration process is determined by the water content of the evaporative concentrated water on which the evaporative concentration process is performed,
The evaporative concentration treatment is performed when the water content of the evaporative concentrated water decreases to one water content set value of 0.7 times or more and 1.3 times or less of the theoretical water content value at which the precipitate theoretically begins to occur. To end ;
(C)
The end of the evaporative concentration process is determined by the conductivity of the evaporative concentrated water on which the evaporative concentration process is performed,
The evaporative concentration treatment is performed when the electric conductivity of the evaporative concentrated water increases to one electric conductivity set value that is 0.9 times or more and 1.5 times or less of the theoretical electric conductivity value at which the precipitate theoretically begins to occur. To end ;
In the solid content producing step, in a precipitation settling tank for producing the solid content from the transferred evaporated concentrated water, the solid content containing the precipitate is stored in a bottom portion,
The solid content stored in the bottom portion, and a liquid content separated from the solid content, further comprising a take-out step of taking out from the precipitation settling tank,
In the extraction step, a method for treating wastewater , wherein the liquid content before being taken out from the precipitation settling tank is agitated by circulating and then the liquid content is taken out, and then the solid content stored in the bottom part is taken out . The precipitation settling tank has an internal volume that allows an operator to take out the solid content inside,
In the extraction step, after removing the liquid component from the precipitation sedimentation tank, the intruded operator to the deposition-precipitation tank, removing said solids accumulated in the bottom portion of the deposition-precipitation tank, in claim 3 Wastewater treatment method described.

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