Method for treating water used in water jet, circulation method, treatment system, and circulation system

Abstract

To regenerate water used in a water jet method into water equivalent to first class industrial water.SOLUTION: The method for treating the used water of the water jet includes a separation step of separating the used water into supernatant water and a flocculate and a step of dehydrating the flocculate to discharge the flocculate as a dehydrated cake. A dehydration step of returning filtered water to supernatant water, a first neutralization step of adding an acid to the supernatant water to neutralize the supernatant water, a first filter passing step of passing the supernatant water through a first filter (palm fiber filter) capable of adsorbing flocs, a second filter passing step of passing the supernatant water through a second filter (cloth filter) capable of rough filtration, an organic matter removing filter passing step of circulating the supernatant water through an organic matter removing filter (activated carbon filter) capable of removing organic matter, and a second neutralization step of adding carbon dioxide gas to neutralize the supernatant water; And a third filter passing step of passing through a third filter (hollow fiber filter) capable of microfiltration.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method, an apparatus, and a system for purifying and reusing used water generated in concrete chipping work using a water jet, surface coating removal work, cleaning work, and the like. [Background technology]

[0002] The water jet (also called "aquablast") is a jet of ultra-high pressure water supplied from a high-pressure water generator and sprayed from a nozzle with fine holes. The water jet method involves chipping concrete with a water jet. For example, water jetting can be used to remove only the concrete without damaging the reinforcing bars inside the concrete. The water jet method can be used to perform work such as chipping concrete decks on bridges and removing deteriorated concrete. In addition to concrete chipping, the water jet method can also be used to remove surface coatings, clean road surfaces, and treat other objects.

[0003] A water tanker truck is transported to the construction site together with the high-pressure water generator, and water is supplied from the water tanker truck to the high-pressure water generator, and a water jet is sprayed from a water jet surface treatment device having a spray nozzle to perform chipping work. The water jet method requires large amounts of water, so water trucks had to be sent to the construction site frequently.

[0004] For this reason, as described in Patent Documents 1 to 6, methods and devices have been proposed that treat the water used in the water jet on-site so that it can be reused.

[0005] In Patent Document 1, when chipping is performed, a predetermined amount of powder or liquid additive is poured into a water storage tank (11) (the symbols in parentheses are symbols given in the patent document, and the same applies below.) In Patent Document 1, a polymer flocculant NP10 (nonionic polyacrylamide) is used as an additive that acts on the concrete fine particles generated by chipping, and sodium bicarbonate is used as an additive that acts on the components contained in the concrete that dissolve in the water used for chipping.

[0006] Patent Document 1 states that since the water for water jetting contains a polymer coagulant, the polymer coagulant contained in the water for water jetting eliminates or weakens the non-affinity caused by the electric charge of the concrete particles during the concrete crushing process, causing the concrete particles to flocculate. The first recovery facility (B2) is said to be equipped with equipment for filtering and disposing of the concrete fine particles that are flocculated and precipitated.

[0007] Usually, water used for water jetting is required to be equivalent to industrial water grade 1. However, it is unclear whether the technology described in Patent Document 1 can treat wastewater to the level of industrial water grade 1, and it cannot be put to practical use as is.

[0008] Patent Document 2 describes a system that includes a chipping robot (1) that performs chipping work using a water jet, a high-pressure water generator (2) that supplies high-pressure water to the chipping robot (1), a water truck (3) that supplies fresh water to the high-pressure water generator (2), a vacuum truck (4) that sucks up wastewater generated during chipping using the water jet, and a solid-liquid separator (5) that performs solid-liquid separation of the recovered wastewater and includes a pump that supplies the treated water to the high-pressure water generator (2).

[0009] Patent Document 2 describes that a sludge dehydration vehicle (product name "Dorodas") manufactured by Kotobuki Giken Kogyo Co., Ltd. is used as a solid-liquid separator (5) to perform solid-liquid separation of turbid water supplied from a vacuum truck (4) and remove solids.

[0010] However, it is not clear what the composition of the product called Dolodus is, and Patent Document 2 simply states that it removes solids from turbid water. According to Patent Document 2, it is not possible to regenerate turbid water into water equivalent to grade 1 industrial water.

[0011] Patent Document 3 describes a steam-water separator (102) that separates gas and liquid, and a filter (108). Contaminated water stored at the bottom of the steam-water separator (102) is discharged through a pipe (105) to a fresh water tank (206) and filtered by the filter (108). This removes surface materials from the contaminated water, and the filtered water is supplied to the fresh water tank (206) as reclaimed water.

[0012] However, there is no description of the structure of the filtering device (108) described in Patent Document 3. According to Patent Document 3, it is not possible to regenerate water equivalent to Grade 1 industrial water.

[0013] The wastewater treatment device described in Patent Document 4 includes a wastewater tank (2), a neutralization device (4), a solid matter removal device (6), and an ion removal device (8). The neutralization device (4) is composed of a static mixer that mixes wastewater with an acidic solution. The neutralization device (4) uses the mixer to mix the wastewater containing the acidic solution as required, thereby neutralizing the water jet wastewater. The solid removal device (6) has a cylindrical removal tank (28) filled with hollow fiber membrane filters. The hollow fiber membrane filter is made of a bundle of hollow fibers with a plurality of holes formed on the circumferential surface, as is well known per se. When a hollow fiber membrane filter is used, the water jet wastewater to be treated flows around the fiber bundle and solids (concrete fragments, etc.) are removed as it flows inside through the holes on the circumferential surface of each fiber, and the wastewater from which the solids have been removed flows through the inside of the fibers. The ion removal device (8) is equipped with a reverse osmosis membrane, and removes ions (calcium ions, chloride ions, etc.) contained in the wastewater as the wastewater passes through the reverse osmosis membrane.

[0014] Thus, Patent Document 4 describes a wastewater treatment process including a neutralization step, a solid matter removal step, and an ion removal step. However, this process cannot regenerate water equivalent to Grade 1 industrial water. Furthermore, in Patent Document 4, a hollow fiber membrane filter is used in the solid matter removal step, but if solid matter is removed using a hollow fiber membrane filter immediately, there is a high possibility that the filter will quickly become clogged.

[0015] Patent Document 5 describes a cleaning vehicle (1) for cleaning road surfaces. The cleaning vehicle (1) is equipped with a water tank (5) on the loading platform, a high-pressure water generating pump (4) that supplies high-pressure water from the water tank (5) to an aquablast (9) that moves along the road, a vacuum device (7) that sucks up the water and suspended solids sprayed from the aquablast (9), and a water recycling device (6) that separates the water and suspended solids sucked up by the vacuum device (7). The water separated and treated by the water recycling device (6) is returned to the water tank and reused at the cleaning site.

[0016] In Patent Document 5, the water recycling device (6) has a processing capacity of, for example, 2 m 3 The filter has a filtration accuracy of SS1μm per hour, and carbon dioxide gas is continuously injected in fixed amounts through the line to separate and process the water and suspended solids sucked from the Aquablast (9). Patent Document 5 states that the reason for injecting carbon dioxide gas through the line is to neutralize the alkaline nature of the water recovered when chipping off a thin layer of concrete.

[0017] The water recycling device (6) is composed of a carbon dioxide gas injection section (32), a reaction tank (33), a filter section (34), and a filtered water tank (35). The filter section (34) is composed of a pair of thickener bag filters (46, 47) each having five 1 μm thickener bags.

[0018] However, it is unclear whether the filter unit (34) of Patent Document 5 can regenerate water equivalent to Grade 1 industrial water. In addition, the filter unit (34) using five 1 μm thickener bags is likely to become clogged quickly. It cannot be recycled to water equivalent to Grade 1 industrial water.

[0019] The water recovery device described in Patent Document 6 is composed of a separation tank (6) equipped with a separation device (1), a neutralization tank (10) equipped with a neutralization device (11), a filter device (14), a water storage tank (15), and a high-pressure pump (17). The neutralization tank (10) is provided with a carbon dioxide gas injection pipe (12a) and an agitator (12b) which constitute a neutralization device (11), and a transfer pump (13) and a pipeline (L3) to a filter device (14). The filter device 14 comprises an upstream filter 14a and a downstream filter 14b, which are integrated into a single unit. The upstream filter 14a has, for example, a 20 micron mesh size and a flow rate of 600 liters per minute. The downstream filter 14b has, for example, a 5 micron mesh size and a flow rate of 600 liters per minute.

[0020] However, the water recovery device of Patent Document 6 cannot regenerate water equivalent to Grade 1 industrial water. [Prior art documents] [Patent documents]

[0021] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-025292 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-242124 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-069957 [Patent Document 4] Japanese Patent Application Publication No. 11-033549 [Patent Document 5] Japanese Patent Application Publication No. 10-082026 [Patent Document 6] Japanese Patent Application Publication No. 09-078854 Summary of the Invention [Problem to be solved by the invention]

[0022] As described above, even if the wastewater recycling devices described in Patent Documents 1 to 6 are used, it is not possible to regenerate water equivalent to industrial water grade 1. Moreover, even if it were possible to regenerate water equivalent to industrial water grade 1, the filters in all of the patent documents are configured so that they are prone to clogging.

[0023] Therefore, an object of the present invention is to regenerate water used in the water jet method into water equivalent to Grade 1 industrial water. Another object of the present invention is to make it difficult for the filter to become clogged when water used in the water jet method is recycled. [Means for solving the problem]

[0024] In order to solve the above problems, the present invention has the following configuration. The present invention is a method for treating used water generated by a water jet, comprising: a separation step in which a coagulant is mixed with sucked used water to separate it into supernatant water and coagulates; a dehydration step in which the coagulates obtained in the separation step are dehydrated and discharged as a dehydrated cake, and the filtrate obtained by dehydration is returned to the supernatant water; a first neutralization step in which acid is added to the supernatant water to neutralize it; a first filter-passing step in which the treated water obtained in the first neutralization step is passed through a first filter capable of adsorbing flocs; a second filter-passing step in which the treated water obtained in the first filter-passing step is passed through a second filter capable of coarse filtration; an organic matter removal filter-passing step in which the treated water obtained in the second filter-passing step is circulated through an organic matter removal filter capable of removing organic matter; a second neutralization step in which carbon dioxide gas is added to the treated water that has passed through the organic matter removal filter-passing step to neutralize it; and a third filter-passing step in which the treated water obtained in the second neutralization step is passed through a third filter capable of fine filtration.

[0025] The present invention also provides a method for circulating used water using a water jet, comprising: a high-pressure water generation process for generating high-pressure water using water supplied from a water supply tank; a treatment process for treating an object with a water jet in which the high-pressure water obtained in the high-pressure water generation process is sprayed from a spray nozzle; a suction process for sucking in the used water generated in the treatment process; a treatment process for treating the used water sucked in in the suction process; and a reuse process for reusing the treated water obtained in the treatment process in the high-pressure water generation process. Here, the treatment process includes a separation process in which a coagulant is mixed with the sucked-in used water to separate it into supernatant water and coagulates; a dehydration process in which the coagulates obtained in the separation process are dehydrated and discharged as a dehydrated cake, and the filtrate obtained by dehydration is returned to the supernatant water; a first neutralization process in which acid is added to the supernatant water to neutralize it; a first filter-passing process in which the treated water obtained in the first neutralization process is passed through a first filter capable of adsorbing flocs; a second filter-passing process in which the treated water obtained in the first filter-passing process is passed through a second filter capable of coarse filtration; an organic matter removal filter-passing process in which the treated water obtained in the second filter-passing process is circulated through an organic matter removal filter capable of removing organic matter; a second neutralization process in which carbon dioxide gas is added to the treated water that has passed through the organic matter removal filter-passing process to neutralize it; and a third filter-passing process in which the treated water obtained in the second neutralization process is passed through a third filter capable of fine filtration.

[0026] Preferably, the first filter is a coconut fiber filter.

[0027] Preferably, the second filter is a filter cloth filter.

[0028] Preferably, the organic matter removal filter is an activated carbon filter.

[0029] Preferably, the third filter is a hollow fiber filter.

[0030] Preferably, in the suction step, the used water can be pumped to the treatment step at the same time as the used water is sucked.

[0031] The present invention also provides a treatment system for used water generated by a water jet, comprising: a separation tank that separates used water mixed with a coagulant into supernatant water and coagulate; a first neutralization tank that adds acid to the supernatant water to neutralize it; a dehydrator that dehydrates the coagulate obtained in the separation tank and discharges it as a dehydrated cake, while returning the filtered water obtained by dehydration to the first neutralization tank; a filter tank that passes the treated water obtained in the first neutralization tank through a first filter capable of adsorbing flocs; a second filter that is capable of coarse filtration and passes the treated water obtained in the filter tank; a treated water stabilization tank that collects the treated water that has passed through the second filter and circulates it to an organic matter removal filter that is capable of removing organic matter; a carbon dioxide gas cylinder that adds carbon dioxide gas to the treated water stabilization tank to neutralize the water; and a third filter that is capable of fine filtration and passes the treated water obtained in the treated water stabilization tank.

[0032] The present invention also provides a system for circulating used water using a water jet, comprising a high-pressure water generating device that generates high-pressure water using water supplied from a water supply tank, a treatment device that treats an object using a water jet that sprays the high-pressure water obtained by the high-pressure water generating device from a spray nozzle, a suction device that sucks up the used water produced by the treatment device, and a treatment system that treats the used water sucked up by the suction device. Here, the treatment system comprises a separation tank that separates used water mixed with a coagulant into supernatant water and coagulates, a first neutralization tank that adds acid to the supernatant water to neutralize it, a dehydrator that dehydrates the coagulates obtained in the separation tank and discharges them as dehydrated cakes, and returns the filtered water obtained by dehydration to the first neutralization tank, a filter tank that passes the treated water obtained in the first neutralization tank through a first filter capable of adsorbing flocs, a second filter capable of coarse filtration that passes the treated water obtained in the filter tank, a treated water stabilization tank that collects the treated water that has passed through the second filter and circulates it to an organic matter removal filter capable of removing organic matter, a carbon dioxide gas cylinder that adds carbon dioxide gas to the treated water stabilization tank to neutralize it, and a third filter capable of fine filtration that passes the treated water obtained in the treated water stabilization tank.

[0033] Preferably, the first filter is a coconut fiber filter.

[0034] Preferably, the second filter is a filter cloth filter.

[0035] Preferably, the organic matter removal filter is an activated carbon filter.

[0036] Preferably, the third filter is a hollow fiber filter.

[0037] Preferably, the suction device is capable of sucking in the used water and simultaneously pumping the used water into the treatment system.

[0038] By mixing a coagulant into the water used, the water can be separated into supernatant water and flocs, and the flocs can be turned into dehydrated cakes in a dehydrator, making the flocs easier to dispose of. The filtered water obtained by dehydration is returned to the supernatant water, allowing for further utilization of the water used.

[0039] The supernatant water is neutralized with acid.

[0040] The amount of flocs in the supernatant can be reduced by leaving the water standing for a longer time until it separates into supernatant and coagulates, but this increases the time required to treat the water used. Therefore, by having the flocs adsorbed on the first filter, the standing time can be minimized.

[0041] The first filter collects the flocs, but since a filter with a very coarse mesh, such as a coconut fiber filter or a sponge filter, can be used as the first filter, clogging of the filter can be minimized.

[0042] The treated water that has passed through the first filter passes through the second filter, which is capable of coarse filtration. Coarse filtration is a filter with a mesh size of 10 μm, such as a filter cloth filter. Coarse filtration makes it possible to filter out flocs that were not removed by the first filter. Because the water has already passed through the first filter, clogging of the second filter can be minimized.

[0043] The treated water that has passed through the second filter is circulated through an organic matter removal filter, where organic matter is removed. An activated carbon filter, for example, is used as the organic matter removal filter. Because the treated water has passed through the second filter, clogging of the organic matter removal filter can be minimized. The organic matter is removed by being adsorbed onto the organic matter removal filter. The treated water can be continuously passed through the organic matter removal filter using a line pump, allowing the organic matter to be continuously removed.

[0044] In addition to the organic matter removal filter treatment, a second neutralization process using carbon dioxide gas is carried out, which neutralizes the treated water.

[0045] Finally, the treated water that has undergone the second neutralization is passed through a third filter capable of microfiltration, and the treated water is reused. A filter capable of microfiltration is a filter with a mesh size of 1 μm. A hollow fiber filter or the like can be used as the third filter. Finally, the water passes through a third filter, resulting in water equivalent to Grade 1 industrial water. By the time the water passes through the third filter, most of the impurities have been removed, which minimizes clogging of the third filter. [Effects of the Invention]

[0046] As described above, according to the present invention, water used in the water jet method can be recycled to water equivalent to Grade 1 industrial water.

[0047] Furthermore, according to the present invention, when water used in the water jet method is recycled, the filter is less likely to become clogged.

[0048] The objects, features, configurations, operations, and effects of the present invention and embodiments of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0049] [Figure 1] FIG. 1 is a system diagram showing the configuration of a processing system 100. [Figure 2] FIG. 2 is a plan view showing the arrangement of the processing system 100 when it is assembled into a main body frame P so that it can be loaded onto a truck. [Figure 3] FIG. 3 is a diagram showing the overall configuration when the water jet method is carried out using the treatment system 100 at a construction site. [Figure 4] 4 is a flowchart showing the steps from receiving used water to reusing treated water in the treatment system 100. In FIG. 4, the numbers (1) to (12) indicate the steps at the locations indicated by the numbers in circles in FIG. 2. [Figure 5] 5 is a flow chart showing the dehydration process of used water. In FIG. 5, the numbers (13) to (15) indicate the steps at the locations of the numbers shown in circles in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0050] As shown in Figures 1 and 2, the treatment system 100 includes a raw water tank A, a generator and workbench B, a control panel and compressor C, a mixing tank D, a separation tank E, a primary neutralization tank F, a filter tank G, a filter cloth filter H, an activated carbon filter I, a treated water stabilization tank J, a hollow fiber filter K, a carbon dioxide cylinder L, a dehydrator M, a diaphragm pump shelf N, a dehydrated cake receiving section O, and a main body frame P.

[0051] As shown in FIG. 3, water is supplied from a water tanker 300 to a high-pressure water generator 400. The water is equivalent to Grade 1 industrial water. The high-pressure water generator 400 supplies the high-pressure water to a water jet surface treatment device 200. The water jet surface treatment device 200 has a spray nozzle. A water jet is sprayed from the spray nozzle to treat objects such as concrete, surface coatings, and road surfaces. The water after the objects have been treated is referred to as used water (also referred to as "wastewater"). In this specification, treated water being treated in the treatment system 100 may also be referred to as used water.

[0052] The suction vehicle 500 sucks up the used water and sends it to the treatment system 100. The suction vehicle 500 is preferably capable of sucking and sending out simultaneously, but this is not limited to this in the present invention. A separate suction vehicle 500 may be used that sucks up and then sends out the used water to the treatment system 100.

[0053] The treatment system 100 reclaims used water into water equivalent to grade 1 industrial water and sends the reclaimed water to the water supply tank 300. Note that instead of sending the treated water to the water supply tank 300, the treatment system 100 may send the treated water to the high-pressure water generator 400. In other words, as long as the treated water is reused, the present invention does not limit the route through which the treated water is reused.

[0054] Needless to say, since this water is equivalent to Grade 1 industrial water, it is not limited to being strictly Grade 1 industrial water.

[0055] The raw water tank A has an inlet that is connected to a delivery hose from the suction vehicle 500. The inlet is preferably located at the bottom of the raw water tank A, but is not limited to this in the present invention. The raw water tank A is preferably equipped with an agitator so that the water to be used therein is agitated, but this is not limited to this in the present invention. A garbage net is provided in the raw water tank A, and it is recommended that the garbage net be used to remove large-diameter garbage in conjunction with stirring, but this is not limited to this in the present invention.

[0056] A water pump (the component indicated by "P" in the drawing is the water pump; the same applies below) is provided at the bottom of raw water tank A. In this embodiment, each water pump is provided at the bottom of the tank, but this is merely an example, and the location of the water pump is not limited in the present invention as long as it can suck up water from within the tank.

[0057] Used water is received from the suction truck 500 into the raw water tank A (step (1) in FIG. 4), and the used water in the raw water tank A is transferred to the mixing tank D by the water pump (step (2) in FIG. 4).

[0058] A generator is installed in the generator and work platform B, and a work platform for various tasks is configured. Control panel and compressor C is equipped with a control panel and compressor.

[0059] An agent dosing device is installed on the top of the mixing tank D. The agent dosing device doses a flocculant as an agent. The flocculant causes particles of dirt (such as concrete powder) that cause turbidity in the water to flocculate. The flocculant is also called floc. Any known flocculant can be used, such as aluminum-based (aluminum sulfate, polyaluminum chloride, etc.), iron-based (ferric polysulfate, ferric chloride, ferrous sulfate, etc.), polymer flocculants, etc. The flocculant may be in either liquid or powder form.

[0060] The chemical dosing device only doses chemicals while used water is being transferred from raw water tank A to mixing tank D. The chemical dosing device defines the time for dosing chemicals according to the flow rate of used water being transferred from raw water tank A to mixing tank D. By controlling the chemical dosing device with a timer via the control panel, it is possible to dose chemicals according to the flow rate. In Figure 4, the process shown as (3) is the process of transferring used water from mixing tank D to separation tank E.

[0061] The separation tank E is a tank for carrying out coagulation treatment. The separation tank E is equipped with an agitator. The agitation time and rest time of the agitator are controlled by a preset timer. The separation tank E is also equipped with a water level sensor. Furthermore, the separation tank E is also equipped with an electric valve. After the water level sensor detects that a predetermined water level has been reached, the electric valve is opened by the control panel after a predetermined rest time has elapsed, and the supernatant water naturally overflows from the separation tank E toward the primary neutralization tank F. In Figure 4, the process indicated by (4) is the separation treatment of the supernatant water and the sediment (coagulate).

[0062] The precipitate (flocculated matter) obtained by the flocculation treatment in the separation tank E is transferred to the dehydrator by a diaphragm pump. In Figure 5, the step indicated by (13) is the transfer treatment of the precipitate.

[0063] The treated water extracted after being dehydrated by the dehydrator M is sent by a diaphragm pump to the primary neutralization tank F. In FIG. 5, the step indicated by (14) is the treated water transfer step.

[0064] The primary neutralization tank F is a tank for neutralizing the supernatant water sent from the separation tank E and the used water sent from the dehydrator M (primary neutralization). The acid introduced into the neutralization tank F is, for example, dilute sulfuric acid, sodium hydrogen sulfate, etc., but is not limited to this in the present invention. The neutralization tank F is equipped with a pH controller. An unillustrated chemical introduction device introduces acid into the neutralization tank F in accordance with the pH detected by the pH controller to neutralize the used water. The used water neutralized by the neutralization tank F naturally overflows into the filter tank G. In Figure 4, the process indicated by (5) is the transfer process of the neutralized used water.

[0065] The filter tank G has at least one coconut fiber filter and a pump tank. Because coconut fiber filters have large mesh, they are not usually used to purify muddy water, but they are used in the present invention. Coconut fiber filters are inexpensive filters.

[0066] For example, six 50mm thick palm fiber filters can be stacked together to form a 300mm thick layer of palm fiber filters.

[0067] In the separation tank E, if the resting time is increased, small flocs can be precipitated. However, if a long resting time is provided, the overall purification time will be long and the treatment capacity will be reduced. Therefore, in this embodiment, the resting time in the separation tank E is set to, for example, about 5 minutes, and the supernatant water is allowed to naturally overflow into the primary neutralization tank F, and passed through the palm fiber filter in the filter tank G while still containing small floating particles. In Figure 4, the step indicated by (6) is the step of passing through the coconut fiber filter.

[0068] Small flocs have the ability to adsorb themselves to something. Utilizing this principle, used water after primary neutralization is passed through a palm fiber filter. This causes the small flocs to be adsorbed onto the palm fiber filter. Palm fiber filters are inexpensive, so they can increase processing capacity while keeping replacement costs down. For example, six 50mm thick palm fiber filters can be combined to form a 300mm thick filter. To reduce the flow rate, the area of ​​the palm fiber filter is increased and the palm fiber filter is layered to make it thicker, allowing more suspended matter to settle on the fibers.

[0069] It should be noted that a coarse sponge filter may be used instead of the coconut fiber filter. That is, the filter used in the filter tank G is preferably a filter (first filter) capable of adsorbing flocs.

[0070] The water that passes through the coconut fiber filter naturally overflows into the pump tank. The treated water is transferred to the filter cloth filter H by a water pump installed in the pump tank. In FIG. 4, the step indicated by (7) is the treated water transfer step.

[0071] For example, a filter cloth with a mesh size of about 10 μm is preferably used as the filter cloth filter H, but this is not limited thereto. If the used water is passed through the filter cloth filter immediately, small flocs will accumulate in the filter cloth filter, causing it to quickly become clogged. In this embodiment, the water is passed through a palm fiber filter (first filter) and then through the filter cloth filter, which allows the filter cloth filter to last longer. The treated water that has passed through the filter cloth filter H is purified to the extent that it contains suspended matter of 10 μm or less. In FIG. 4, the step indicated by (8) is the step of passing through the filter cloth.

[0072] The filter cloth filter can be replaced with another well-known filter as long as it is capable of coarse filtration (filtration that can capture objects larger than 10 μm. Filtration using a filter with a mesh size of 10 μm). The filter cloth filter will be referred to as the second filter.

[0073] The treated water that has passed through the filter cloth is transferred to the treated water stabilization tank J. In the treated water stabilization tank J, the activated carbon filter process ((9) in Figure 4) and the secondary neutralization process ((10) in Figure 4) are carried out.

[0074] The activated carbon filter I is connected to the treated water stabilization tank J by a line pump (circulation pump). Therefore, the treated water in the treated water stabilization tank J is sucked into the activated carbon filter I by the line pump, and the treated water that passes through the activated carbon filter I returns to the treated water stabilization tank. As the treated water passes through the activated carbon filter I, mainly organic matter is adsorbed onto the activated carbon filter I.

[0075] The activated carbon filter I removes organic matter. Therefore, the activated carbon filter I can be replaced with other well-known organic matter removal filters.

[0076] Carbon dioxide gas is also supplied to the treated water stabilization tank J from a carbon dioxide gas cylinder L. The supply of carbon dioxide gas to the treated water carries out neutralization. A pH controller is installed in the treated water stabilization tank J, which measures the pH. Based on the measured pH, the control panel controls the amount of carbon dioxide gas supplied.

[0077] In this way, the treated water is neutralized (secondary neutralization) in the treated water stabilization tank J, and organic matter is removed, thereby stabilizing the treated water.

[0078] The treated water is sucked in by a water pump installed in the treated water stabilization tank J, and finally passes through a hollow fiber filter K ((11) in Figure 4). The mesh of the hollow fiber filter K is 1 μm or less, and the target objects to be captured are 1 μm or larger. Such a filter with a mesh of 1 μm or larger is called a microfiltration filter. The hollow fiber filter K can be replaced with other well-known microfiltration filters capable of microfiltration.

[0079] By passing the water through the hollow fiber filter K, the remaining impurities and the activated carbon powder present in the activated carbon filter I can be filtered out.

[0080] The final treated water that has passed through the hollow fiber filter K is reused ((12) in FIG. 4).

[0081] As the dehydrator M, for example, a table-type filter press such as that described in JP 2021-023884 A can be used. For example, this table-type filter press uses a 2-in, 2-out diaphragm pump. The sediment (floc) is sucked from the separation tank E, passed through a filter chamber lined with filter cloth, and pressed to remove water from the sediment. The filtered water is transferred to the primary neutralization tank F, and the dehydrated cake is discharged (Figure 5 (15)).

[0082] The dewatering machine M may have any structure as long as it can dewater the flocs and separate the dewatered cake from the filtrate, and any known technology can be used. The configuration of the dewatering machine M is not limited in the present invention.

[0083] The diaphragm pump shelf N is a shelf for placing a diaphragm pump. The dehydrated cake receiving portion O is a portion that receives the dehydrated cake.

[0084] The main body frame P is a frame that allows the processing system 100 to be mounted on a truck.

[0085] As described above, this embodiment includes a coagulation process in which a coagulant is mixed with the water used to separate it into supernatant water and sediment, a primary neutralization process in which acid is added to the supernatant water to neutralize it, a first filter-passing process in which the treated water is passed through a first filter such as a palm fiber filter that can adsorb flocs to adsorb the flocs, a coarse filter-passing process in which the treated water that has passed through the first filter is passed through a coarse filter such as a filter cloth filter, an organic matter removal process in which the treated water that has passed through the coarse filter is passed through an organic matter removal filter such as activated carbon, a secondary neutralization process in which carbon dioxide gas is introduced in conjunction with the organic matter removal process, and finally a microfilter-passing process in which the treated water is passed through a microfilter such as a hollow fiber filter.This enables the water used in the water jet method to be recycled into water equivalent to Grade 1 industrial water and reused in the water jet method.

[0086] The wastewater is separated into flocs and supernatant water, the flocs are dehydrated, and the supernatant water is passed through a coconut fiber filter, which makes it less likely for the filter cloth filter or hollow fiber filter to become clogged.

[0087] By attaching the flocs to the palm fiber filter, the settling time of the flocs can be shortened.

[0088] Although the present invention has been described in detail above, the above description is merely illustrative of the present invention in all respects and is not intended to limit its scope. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. Each of the constituent elements of the invention disclosed in this specification is considered to be an independent, stand-alone invention. Inventions that combine the constituent elements in any manner are also included in the present invention. The specific expressions in this specification are merely examples, and the present invention also includes those that conceptualize these exemplary expressions. [Industrial Applicability]

[0089] The present invention provides a method for treating water used in a water jet, a circulation method, a treatment system, and a circulation system, and is industrially applicable. [Explanation of symbols]

[0090] 100 Processing Systems 200 Water jet surface treatment equipment 300 Water tanker 400 High-pressure water generator 500 suction car A raw water tank B Generator / Workbench C Control panel / Compressor D Mixing Tank E Separation tank F Primary neutralization tank G Filter Tank H Filter cloth filter I Activated carbon filter J Treated water stabilization tank K hollow fiber filter L carbon dioxide cylinder M Dehydrator N Diaphragm Pump Shelf O Dewatered cake receiving section P Main frame

Claims

1. 1. A method for treating used water generated by a water jet, comprising: a separation step of mixing a flocculant with the sucked water to be used and separating the water into supernatant water and flocculants; a dehydration step in which the flocculated material obtained in the separation step is dehydrated to form a dehydrated cake and discharged, and the filtrate obtained by the dehydration is returned to the supernatant water; a first neutralization step of adding an acid to the supernatant water to neutralize it; a first filter passing step of passing the treated water obtained in the first neutralization step through a first filter capable of adsorbing flocs; a second filter passing step of passing the treated water obtained in the first filter passing step through a second filter capable of rough filtration; an organic matter removal filter passing step in which the treated water obtained in the second filter passing step is circulated through an organic matter removal filter capable of removing organic matter; a second neutralization step of neutralizing the treated water that has passed through the organic matter removal filter by adding carbon dioxide gas; a third filter passing step of passing the treated water obtained in the second neutralization step through a third filter capable of precision filtration.

2. 2. The method of claim 1, wherein the first filter is a palm fiber filter.

3. 2. The method of claim 1, wherein the second filter is a filter cloth filter.

4. 2. The treatment method according to claim 1, wherein the organic matter removal filter is an activated carbon filter.

5. 2. The method according to claim 1, wherein the third filter is a hollow fiber filter.

6. A method for circulating used water using a water jet, comprising: a high-pressure water generating step of generating high-pressure water using water supplied from a water supply tank; a treatment step of treating an object with a water jet by spraying the high-pressure water obtained in the high-pressure water generation step from a spray nozzle; a suction step of suctioning the used water produced in the treatment step; a treatment step of treating the used water sucked in the suction step; a recycling step of recycling the treated water obtained in the treatment step for the high-pressure water generation step, The processing step comprises: a separation step of mixing a flocculant with the sucked water to be used and separating the water into supernatant water and flocculants; a dehydration step in which the flocculated material obtained in the separation step is dehydrated to form a dehydrated cake and discharged, and the filtrate obtained by the dehydration is returned to the supernatant water; a first neutralization step of adding an acid to the supernatant water to neutralize it; a first filter passing step of passing the treated water obtained in the first neutralization step through a first filter capable of adsorbing flocs; a second filter passing step of passing the treated water obtained in the first filter passing step through a second filter capable of rough filtration; an organic matter removal filter passing step in which the treated water obtained in the second filter passing step is circulated through an organic matter removal filter capable of removing organic matter; a second neutralization step of neutralizing the treated water that has passed through the organic matter removal filter by adding carbon dioxide gas; a third filter passing step of passing the treated water obtained in the second neutralization step through a third filter capable of microfiltration.

7. 7. The circulation method of claim 6, wherein the first filter is a coconut fiber filter.

8. 7. The circulation method according to claim 6, wherein the second filter is a filter cloth filter.

9. 7. The circulation method according to claim 6, wherein the organic matter removal filter is an activated carbon filter.

10. 7. The circulation method according to claim 6, wherein the third filter is a hollow fiber filter.

11. 7. The circulation method according to claim 6, wherein the suction step is capable of simultaneously suctioning the used water and pumping the used water to the treatment step.

12. 1. A system for treating used water generated by a water jet, comprising: a separation tank for separating the water mixed with the flocculant into supernatant water and flocculants; a first neutralization tank for adding an acid to the supernatant water to neutralize it; a dehydrator that dehydrates the coagulate obtained in the separation tank to form a dehydrated cake and discharges it, and returns the filtrate obtained by the dehydration to the first neutralization tank; a filter tank for passing the treated water obtained in the first neutralization tank through a first filter capable of adsorbing flocs; a second filter capable of rough filtration through which the treated water obtained in the filter tank passes; a treated water stabilization tank that stores the treated water that has passed through the second filter and circulates it to an organic matter removal filter that can remove organic matter; a carbon dioxide gas cylinder for adding carbon dioxide gas to the treated water stabilization tank to neutralize the water; and a third filter capable of microfiltration through which the treated water obtained in the treated water stabilization tank passes.

13. 13. The treatment system of claim 12, wherein the first filter is a palm fiber filter.

14. 13. The treatment system of claim 12, wherein the second filter is a filter cloth filter.

15. 13. The treatment system according to claim 12, wherein the organic matter removal filter is an activated carbon filter.

16. 13. The treatment system of claim 12, wherein the third filter is a hollow fiber filter.

17. A water circulation system using a water jet, a high-pressure water generator that generates high-pressure water using water supplied from a water supply tank; a treatment device for treating an object with a water jet generated by spraying the high-pressure water generated by the high-pressure water generator from a spray nozzle; a suction device for suctioning used water produced in the treatment device; a treatment system for treating the used water sucked by the suction device, The processing system includes: a separation tank for separating the water mixed with the flocculant into supernatant water and flocculants; a first neutralization tank for adding an acid to the supernatant water to neutralize it; a dehydrator that dehydrates the coagulate obtained in the separation tank to form a dehydrated cake and discharges it, and returns the filtrate obtained by the dehydration to the first neutralization tank; a filter tank for passing the treated water obtained in the first neutralization tank through a first filter capable of adsorbing flocs; a second filter capable of rough filtration through which the treated water obtained in the filter tank passes; a treated water stabilization tank that stores the treated water that has passed through the second filter and circulates it to an organic matter removal filter that can remove organic matter; a carbon dioxide gas cylinder for adding carbon dioxide gas to the treated water stabilization tank to neutralize the water; a third filter capable of microfiltration through which the treated water obtained in the treated water stabilization tank passes.

18. 18. The circulation system of claim 17, wherein the first filter is a palm fiber filter.

19. 18. The circulation system of claim 17, wherein the second filter is a filter cloth filter.

20. 18. The circulation system according to claim 17, wherein the organic matter removal filter is an activated carbon filter.

21. 18. The circulation system of claim 17, wherein the third filter is a hollow fiber filter.

22. 18. The circulation system according to claim 17, wherein the suction device is capable of sucking in the used water and simultaneously pumping the used water into the treatment system.

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