JP2004267892A - Wastewater treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To certainly wash a hollow fiber membrane to always stably perform wastewater cleaning treatment. <P>SOLUTION: The subject wastewater treatment equipment is equipped with a hollow fiber membrane filter device 5 for filtering impurities when wastewater passes through the hollow fiber membrane, a clean air generator 8 constituted so that compressed air is fed under pressure from the inside of the hollow fiber membrane to peel impurities bonded to the surface of the hollow fiber membrane and further fed to the surface of the hollow fiber membrane under pressure and ejected to allow peeled impurities to fall to wash the hollow fiber membrane, and chemical equipment 9 for treating impurities with a chemical liquid of an acid, alkali, or the like, when impurities are still bonded to the surface of the hollow fiber membrane washed by the clean air generator 8 to remove the same. By this constitution, the washing of the hollow fiber membrane is certainly performed to always stably perform wastewater cleaning treatment. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wastewater treatment facility for purifying wastewater from a coal storage yard of a coal-fired power plant and raw water from a coal transportation facility system.
[0002]
[Prior art]
In general, in coal-fired power plants, water is sprayed to prevent spontaneous ignition from the coal storage yard, and the drainage and rainwater are once stored in a drainage storage tank, then filtered by a sand filtration device and discharged to the outside. I have. Raw water from the coal transportation system flows into this drainage storage tank and is stored.
[0003]
In this way, after the water is stored in the drainage storage tank, it is filtered by the sand filtration device and discharged to the outside because the high-concentration pulverized coal, which is an insoluble impurity in the wastewater from the coal storage plant and the raw water from the coal transportation system, This is because impurities cannot be discharged to rivers or the like as they are.
[0004]
By the way, if all of the treated water after being treated by the sand filtration device is discharged to rivers, etc., the water used for sprinkling water at the coal storage yard and the coal transportation equipment system will use new industrial water or river water. It is uneconomical.
[0005]
Therefore, a configuration in which a filtration device using a hollow fiber membrane is introduced instead of a sand filtration device so that the wastewater filtered by the hollow fiber membrane filtration device can be supplied as water used for watering in a coal storage plant or a coal transportation system. It has been proposed (see Patent Documents 1 and 2).
[0006]
FIG. 2 is a schematic configuration diagram of a wastewater treatment facility provided with such a hollow fiber membrane filtration device. In the wastewater treatment facility, rainwater and sprinkling water from the coal storage facility 11 and raw water as wastewater from the coal transportation facility system 12 are temporarily stored in a wastewater storage tank 13 and then pumped to a hollow fiber membrane filtration device 15 by a pump 14. Then, an impurity removal process is performed.
[0007]
Then, part of the wastewater subjected to the impurity removal treatment is supplied to the coal storage plant 11 as water for sprinkling, part of the wastewater is supplied as water used in the coal transport facility system 12, and the rest is discharged to rivers and the like. The water has been effectively used.
[0008]
In addition, since coal fine powder, diatomaceous earth of a kaolin component, and other organic substances are intricately contained as insoluble impurities contained in water filtered by the hollow fiber membrane filtration device 15, these adhere to the hollow fiber membrane and The pressure difference between the inside and outside of the hollow fiber membrane rapidly rises frequently.
[0009]
A sudden rise in the differential pressure between the inside and outside of the hollow fiber membrane means a decrease in the filtration capacity of the hollow fiber membrane. Therefore, air backwashing is performed by flowing air from the inside of the hollow fiber membrane for washing.
[0010]
[Patent Document 1]
JP 2001-276581 A [Patent Document 1]
JP 2001-145822 A
[Problems to be solved by the invention]
However, in the air backwashing, there is a case where impurities adhering to the hollow fiber membrane cannot be sufficiently washed, and there is a problem that the life of the hollow fiber membrane may be deteriorated.
[0012]
Therefore, an object of the present invention is to provide a wastewater treatment facility capable of always performing a stable wastewater purification treatment by reliably performing the cleaning of the hollow fiber membrane.
[0013]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is a wastewater treatment facility for purifying wastewater from a coal storage yard or a coal transportation facility system, etc., wherein the wastewater is formed by a hollow fiber membrane, and the wastewater flows through the hollow fiber membrane. A hollow fiber membrane filtration device that filters impurities when passing therethrough, and pressurized air from the inside of the hollow fiber membrane to separate impurities adhering to the surface of the hollow fiber membrane and compress air to the separated impurities. A cleaning air generator for spraying and dropping water, and a chemical for removing impurities by a chemical solution treatment when impurities are still attached to the surface of the hollow fiber membrane cleaned by the cleaning air generator. It is characterized in that a stable wastewater purification treatment can always be performed by providing equipment and making sure that the hollow fiber membrane can be washed.
[0014]
The invention according to claim 2 is characterized in that the hollow fiber membrane filtration device is formed by a plurality of filters formed by hollow fiber membranes, and is provided so that each filter can operate independently. And
[0015]
The invention according to claim 3 is characterized in that the maximum flow rate of the drainage passing through the hollow fiber membrane in the filter is 0.1 meter / hour.
[0016]
The invention according to claim 4 is characterized in that the hollow fiber membrane is formed of any one of ceramic, filter cloth, sintered metal and cartridge filter.
[0017]
The invention according to claim 5 is characterized in that the chemical equipment is provided with an acid such as hydrochloric acid, sulfuric acid and oxalic acid, and an alkali such as potassium isoda and the like, and performs chemical treatment of impurities.
[0018]
The invention according to claim 6 is characterized in that the chemical equipment is provided with a reducing agent such as hydrogen peroxide and performs chemical treatment of impurities.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a wastewater treatment apparatus according to the present invention.
[0020]
The wastewater treatment device stores water sprinkling and rainwater from a coal storage yard 1 for storing coal, and a drainage storage tank 3 for storing wastewater from a coal transportation system 2, and the wastewater stored in the wastewater storage tank 3 is supplied. The hollow fiber membrane filtration device 5 that purifies the wastewater, the cleaning air generator 8 that sends air when cleaning impurities attached to the hollow fiber membrane of the hollow fiber membrane filtration device 5, When impurities are not sufficiently washed by the air from the washing air generator 8, a chemical facility 9 for performing chemical treatment and washing, and finally adjusting the pH of the purified water to be discharged or discharged to a coal storage plant. 1 and a PH treatment tank 6 for supplying water to the coal transportation system 2.
[0021]
The hollow fiber membrane filtration device 5 has a plurality of filters having the same configuration. Although two filters 5a and 5b are illustrated in FIG. 1, more filters may be provided. Hereinafter, such filters are collectively referred to as a filter 5 as appropriate.
[0022]
Such a filter 5 is configured by densely arranging hollow fiber membrane filter modules, and is capable of capturing fine impurities as compared with a sand filtration device. It is possible to select and use ceramic, filter cloth, sintered metal, cartridge and the like according to the properties of the waste water (water quality depending on the type of impurities contained).
[0023]
Needless to say, since chemical treatment is performed at the time of cleaning as described later, a substance which does not cause corrosion or the like due to the chemical at that time is selected and used.
[0024]
The cleaning air generator 8 includes a primary pipe 8a connected to a primary side (a side to which filtered water is supplied) of the filter 5 and a secondary pipe 8a connected to a secondary side (a side from which filtered water is discharged). The generated compressed air is supplied to the filter 5 via the secondary pipe 8b.
[0025]
Then, by sending compressed air from the secondary pipe 8b to the inside of the hollow fiber membrane, water is caused to flow from the inside to the outside of the hollow fiber membrane to remove impurities adhering to the surface of the hollow fiber membrane.
[0026]
Further, by sending compressed air from the primary pipe 8a to the surface of the hollow fiber membrane and injecting the compressed air, the hollow fiber membrane is vibrated so that the separated impurities fall and can be discarded as filtration residue.
[0027]
The chemical equipment 9 is provided with an acid such as hydrochloric acid, sulfuric acid and oxalic acid, an alkali such as potassium isoda, a reducing agent such as hydrogen peroxide, etc. to dissolve and wash impurities adhering to the hollow fiber membrane, and The impurities are reduced and washed.
[0028]
In such a configuration, rainwater and sprinkling drainage from the coal storage plant 1 and drainage from the coal transportation system 2 are guided to the drainage storage tank 3 and temporarily stored in the drainage storage tank 3. The pressure is sent to the filtration device 5.
[0029]
The water purified by the hollow fiber membrane filtration device 5 is subjected to PH treatment in the PH treatment tank 6, and part of the water is supplied to the coal storage plant 1 as water for sprinkling, and part of the water is supplied as water used in the operation facility system 2. The rest is drained to rivers, etc., and the water is effectively used.
[0030]
If the fine impurities are continuously captured by the hollow fiber membrane filtration device 5, the impurities may adhere to the surface of the hollow fiber membrane to cause clogging, and the pressure difference between the inside and outside of the hollow fiber membrane may reach a specified value. In such a case, the cleaning is performed using the cleaning air generator 8 to recover the purification processing ability.
[0031]
However, depending on the state of adhesion of impurities and the like, there is a case where the cleaning processing ability is not sufficiently restored by cleaning with the cleaning air generator 8. In such a case, cleaning is performed by the chemical facility 9.
[0032]
In the cleaning by the chemical equipment 9, the acid chemicals provided are converted into a solution having a specified concentration, supplied to the filter 5, and held for a predetermined time. As a result, the acid solution dissolves impurities and the cleaning is performed.
[0033]
When the dissolution washing with the acid chemical is completed, the acid solution is drained and washed with water, and then the alkali chemical provided is converted into a solution having a specified concentration and supplied to the filter 5 and maintained for a specified time under temperature control. I do. As a result, the alkaline solution dissolves impurities, and cleaning is performed.
[0034]
After that, the alkaline solution is drained, and water cleaning is performed to complete chemical cleaning.
[0035]
In this manner, washing is performed with an acid and an alkali chemical. However, if impurities are not sufficiently washed and removed and the pressure difference between the inside and outside of the hollow fiber membrane is not recovered, reduction washing with a reducing agent such as hydrogen peroxide is performed. Add and do.
[0036]
Thereby, the hollow fiber membrane can be recovered to a substantially initial state, and can be used continuously.
[0037]
During the air cleaning or the chemical cleaning, the filter 5 cannot be used for the purification treatment. For example, if the purification treatment ability is reduced while supplying the wastewater to all the filters 5 to perform the purification treatment, the filter 1 is not cleaned. Washing may be performed one by one in order, or drainage may be supplied to a part of the filter 5 to perform a purification process. When the purification processing capability of the filter 5 decreases, the filter 5 is started to be cleaned. In the meantime, the purification process may be performed by another filter 5.
[0038]
These can be properly used because the hollow fiber membrane filtration device 5 is formed by a plurality of filters 5.
[0039]
In addition, since a plurality of filters 5 are provided in this manner, the processing load on each filter 5 can be reduced, and the passage speed of water when passing through the hollow fiber membrane can be reduced. And the differential pressure between the inside and outside slowly rises, so that it takes a long time to reach the prescribed control differential pressure, and a large amount of wastewater can be treated.
[0040]
Even in that case, it is preferable to set the maximum passage speed of the hollow fiber membrane to 0.1 m / h.
[0041]
As described above, it is possible to appropriately remove impurities in rainwater and sprinkled water drained from the coal storage yard, so that the rainwater and sprinkled water discharged from the coal storage yard can be used as water for sprinkling the coal storage yard and water for the site. As a result, the load on the environment is reduced, and the life of the hollow fiber membrane is extended, so that the running cost can be greatly reduced.
[0042]
【The invention's effect】
As described above, according to the present invention, a hollow fiber membrane filtration device formed of a hollow fiber membrane to filter impurities when wastewater passes through the hollow fiber membrane, and compressed air from the inside of the hollow fiber membrane To remove impurities adhering to the surface of the hollow fiber membrane, and spraying compressed air onto the separated impurities to drop and clean the impurities. When impurities are still attached to the surface of the hollow fiber membrane, a chemical facility for removing the impurities by treatment with a chemical solution is provided, so that the hollow fiber membrane can be reliably washed, Stable wastewater purification treatment can be performed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a wastewater treatment apparatus applied to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a wastewater treatment apparatus applied to a description of a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Coal storage plant 2 Operating equipment system 2 Coal transportation equipment system 3 Drainage storage tank 4 Water supply pump 5 Hollow fiber membrane filtration equipment 5a, 5b Filtration equipment 8 Cleaning air generation equipment 9 Chemical equipment

Claims (6)

In wastewater treatment facilities that purify wastewater from coal storage yards and its coal transportation equipment systems,
A hollow fiber membrane filtration device formed of a hollow fiber membrane, which filters impurities when the wastewater passes through the hollow fiber membrane,
A cleaning air generator that pressurizes compressed air from the inside of the hollow fiber membrane to peel off the impurities attached to the surface of the hollow fiber membrane, and also jets compressed air to the separated impurities to drop and clean the air. When,
A wastewater treatment facility comprising: a chemical facility for removing impurities on the surface of the hollow fiber membrane that has been washed by the washing air generator by performing a chemical treatment. The hollow fiber membrane filtration device is formed by a plurality of filters formed by hollow fiber membranes, and is provided so that each filter can operate independently. Wastewater treatment facility. The wastewater treatment equipment according to claim 1 or 2, wherein a maximum passage speed of the wastewater passing through the hollow fiber membrane in the filter is 0.1 meter / hour. The wastewater treatment facility according to any one of claims 1 to 3, wherein the hollow fiber membrane is formed of any one of a ceramic, a filter cloth, a sintered metal, and a cartridge filter. The wastewater treatment equipment according to any one of claims 1 to 4, wherein the chemical equipment is provided with an acid such as hydrochloric acid, sulfuric acid, and oxalic acid, and an alkali such as caseide so as to treat the impurities with a chemical solution. The wastewater treatment equipment according to any one of claims 1 to 5, wherein the chemical equipment includes a reducing agent such as hydrogen peroxide, and performs a chemical treatment on the impurities.

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