JP2014079675A - Flushing treatment method and flushing water treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent discharge of flushing drain water itself, by continuously sending-circulating water in a pipe or purifying the water used for flushing by coagulating/precipitating an unprecipitative fine zinc particulate and a dissolved zinc ion and surely separating flushing water into fresh water (clean supernatant water) and precipitation sludge, when executing flushing treatment on the pipe.SOLUTION: Flushing water taken from pipe systems A, B and C is made to flow into a raw water tank 31 of a flushing water purifier 21 from a branch pipe 22. The raw water tank 31 is connected with a vacuum deaeration pump 37, and since a gaseous phase part in the tank is decompressed more than atmospheric pressure, a fine bubble in the flushing water can be quickly removed. A coagulated object is not joined to the fine bubble even if condensation treatment and coagulation treatment are executed in a reaction tank 41 thereafter, so that the coagulation object does not float in a first precipitation tank 51 and a second precipitation tank 52.

Description

  The present invention relates to a method and a flushing water treatment system for flushing a piping system of equipment having galvanized steel pipes.

  In piping equipment, before starting operation after construction, flushing processing is performed for the purpose of removing turbidity components and dust to which metal fume in the pipe has adhered. Flushing treatment, for example, for the purpose of removing iron powder, cutting oil, zinc oxide, joining materials, etc., generated by connecting, cutting, and welding work from the piping system before the trial operation of the piping system, etc., from the piping system For example, a fluid such as water is allowed to flow through the piping to clean it.

  Conventionally, flushing water after flushing is discharged outside the piping system, but in galvanized piping, flushing water after treatment contains high concentrations of zinc, which has an adverse effect on the ecosystem. Yes. In particular, in flushing treatment of galvanized pipes welded on-site, the wastewater level (2 mg / liter or less; in some regions 0.5 mg / liter or less) far exceeds 100 mg / liter or more. May contain zinc.

  According to the 2009 Air Conditioning and Sanitation Engineering Association's construction maintenance information and air conditioning piping system reliability improvement study subcommittee report, the flushing wastewater is being properly treated (detoxification treatment) The questionnaire results with 20% of the total are shown. It is pointed out that “a proper processing method has not been specified” as the cause. Therefore, in many sites so far, flushed waste water is diluted with a large amount of water and drained. However, even if the flushing wastewater can be diluted with water to clear the concentration control, it does not reduce the absolute discharge amount of harmful substances, and it has not fundamentally improved for environmental conservation. Currently.

  On the other hand, depending on the conditions of the flushing wastewater, it can be treated to some extent by filtration with a filter. However, the filter required for the treatment needs to have a specification that can remove fine turbidity at a level of 1 μm with high performance, and an enormous quantity is required. Therefore, as a result, the total amount of industrial waste including the filter is increased, resulting in a new problem of greatly increasing the processing cost. Further, the pH of the flushing wastewater is usually in the range of pH 6 to 8, and in this range, there is a problem that many zinc components are present as ions and cannot be removed by the filter.

  For this reason, at present, there is no direct conventional existing technique for removing zinc in flushing wastewater from a piping system of a facility in which a galvanized steel pipe is piped (Non-Patent Document 1).

  In this regard, the following techniques have conventionally been proposed as a general method for treating zinc-containing wastewater. That is, after alkalizing the zinc-containing wastewater, an inorganic coagulant is added, and then a polymer flocculant is added to separate sludge in a sedimentation tank. This is a method in which the pH is neutralized to the wastewater treatment standard and drained (Patent Documents 1, 2, and 3).

JP 58-19498 A Japanese Patent Laid-Open No. 11-188208 JP-A-11-290865

Japan Air Conditioning and Sanitary Engineering Association Construction Maintenance Committee “Investigation Study on Construction Maintenance Information and Air-conditioning Piping System Reliability Improvement” March 2009

  The above-described problem of flushing drainage is due to the fact that the flushed water was originally discharged as wastewater outside the treatment system. Therefore, if the flushing water that has been drained outside the system after the flushing treatment so far is purified on-site without draining at all and turbidity components containing harmful zinc are separately removed as sludge, the environment described above This is thought to lead to the solution of conservation problems.

  However, if the conventional technology is combined, fine zinc particles that are difficult to settle and dissolved zinc ions are coagulated and settled by chemical addition treatment, separated into fresh water (clean supernatant water) and precipitated sludge, When a flushing treatment system that returns fresh water to the piping system was constructed and actually tested, in some piping facilities, a part of the aggregate (sludge) that should be originally settled and separated in the settling tank, I fell into a situation where I could not get Shimizu. With this, it is possible to continuously feed and circulate the inside of the piping to continuously peel and clean fumes and welding debris generated during welding, and to return the flushing water after cleaning to the piping system again without discharging it outside the system. In reality, this is not possible, and if it is drained unavoidably, it will eventually cause environmental pollution.

  The present invention has been made in view of the above points, and agglomerates and settles fine zinc fine particles that are difficult to settle and dissolved zinc ions, and reliably separates them with clean water (clean supernatant water) and precipitated sludge. The purpose is to continuously circulate the water in the piping or purify the water used for the flushing so that the drainage itself is not necessary.

  As a result of earnestly elucidating the cause of the fact that a part of the aggregate (sludge) that should be originally settled and separated in the settling tank as described above has risen and the fresh water cannot be obtained, the inventors are as follows. It has been found. In other words, the water pressure in the pipe during the flushing process varies depending on the form of the pipe, but the lowermost part where water is taken is a pressure equivalent to the head of the pipe, that is, a pressure higher than the atmospheric pressure, which is more than under atmospheric pressure. Air is dissolved. When water in this state is taken, the water pressure is reduced to the atmospheric pressure level, so that part of the dissolved air is gasified as fine bubbles. When a drug is added and agglomeration treatment is performed in a state where fine bubbles are mixed in water, the fine bubbles and the aggregates are combined, and even after precipitation, the aggregates associated with the fine bubbles are floated. It turned out to be.

  Accordingly, the present invention provides a method for flushing water by flowing water through the piping of equipment, and taking out part or all of the flushing water flowing through the piping during the flushing treatment, and removing the flushed water taken out from the gas phase section in the tank. After passing through the raw water tank whose pressure is lower than the atmospheric pressure, the flushing water from the raw water tank is subjected to a condensation treatment and agglomeration treatment. It is characterized by returning the supernatant water into the piping system.

  In the present invention, since the flushing water taken out from the piping system is passed through the raw water tank whose pressure in the gas phase in the tank is lower than the atmospheric pressure, the condensation treatment and the aggregation treatment are performed. It is possible to quickly deaerate and remove the air that has dissolved into the fine bubbles. Therefore, even if a coagulation process and a coagulation process are subsequently performed, it is possible to prevent the aggregates from being combined with fine bubbles as in the conventional case. Even if the precipitation process is performed, the aggregates do not float, and during the precipitation process, It is possible to collect the supernatant water and return it to the piping system. In addition, wastewater mixed with contaminants such as zinc is not discharged out of the system as in the past.

  The pressure in the gas phase portion in the raw water tank is preferably 5 kPa or more lower than the atmospheric pressure (98.1 kPa), and is preferably 10 kPa to 90 kPa in practice. The allowable pressure depends on the residence time and the adoption of a structure that can be easily degassed, which will be described later in the embodiment. However, according to the inventor's knowledge, there is an improvement effect even if it is lower than atmospheric pressure by about 5 kPa. Guessed.

  As the flushing water treatment system used when carrying out the flushing treatment method, the flushing water taken from the pipe is purified, and the flushing water after purification is connected in parallel with the pipe so as to return to the pipe. The flushing water purification apparatus has a raw water tank, a reaction tank in which a coagulant and a flocculant are sequentially added to the water from the raw water tank, and agglomeration contained in the water from the reaction tank. It is possible to propose a flushing water treatment system having a sedimentation tank for precipitating a substance, and a pump for decompressing the gas phase in the tank is connected to the raw water tank.

  In this case, the raw water tank flows near the water surface, that is, on the surface layer part at least once while the flushing water flows from the inflow part of the flushing water into the tank to the outflow part to the reaction tank. It is preferable that a rectifying mechanism for rectifying the water flow of the flushing water is provided between the inflow portion and the outflow portion.

  Further, it can be proposed that the rectifying mechanism is a plate body provided in a vertical direction in the tank, the inflow portion is set in the lower portion in the tank, and the outflow portion is set in the lower portion in the tank.

  Further, the rectifying mechanism is a plate body that extends obliquely upward from the inner wall of the tank in the tank, the inflow part is set in the upper part of the tank on the base side of the plate body, and the outflow part is in the lower part of the tank You may make it set.

  A plurality of the plate bodies may be provided. In this case, it is preferable that the plate bodies are alternately arranged in a staggered manner as viewed from the side of the raw water tank.

  According to the present invention, even if the precipitation treatment is performed after the condensation treatment and the agglomeration treatment, the agglomerate does not float, so the supernatant water at the time of the precipitation treatment is recovered and returned to the piping system. And flushing waste water is not discharged out of the system.

It is explanatory drawing which showed typically the outline of the system | strain of the system for implementing embodiment. It is explanatory drawing which showed typically the structure of the flushing water purification apparatus in the system of FIG. It is explanatory drawing which showed typically the other structural example of the raw | natural water tank. It is explanatory drawing which showed typically the other structural example of the raw | natural water tank which has arrange | positioned the vertical board in zigzag form seeing from the side surface. It is explanatory drawing which showed typically the other structural example of the raw | natural water tank which provided the inclination board.

  Embodiments of the present invention will be described below. FIG. 1: has shown the outline of the system | strain of the flushing processing system for implementing the processing method of the flushing water concerning embodiment, This system was applied to the piping system etc. of the cold water from the refrigerator 1 It is. Cold water from the refrigerator 1 is sent from the outlet side cold water pipe 3 to the dispersion unit 4 (in the illustrated example, a header) by the pump 2. Cold water is supplied from the dispersing unit 4 to the outgoing pipe side of a plurality of piping systems A, B, C connected to the demand side load through the outgoing pipes As, Bs, Cs. Further, the chilled water heated from the return pipe side of the piping systems A, B, and C is returned to the collecting section 5 (in the illustrated example, the header) through each return pipe system pipe Ar, Br, Cr, and the refrigerator 1 is returned from the inlet side cold water pipe 6 to the refrigerator 1. In FIG. 1, the valve symbol indicated by black indicates a closed state, and the valve symbol indicated by white indicates an open state.

  The outlet side cold water pipe 3 is provided with a valve V1, a pump 2, a check valve 11, a valve V2, and a valve V3 in order from the refrigerator 1 to the dispersion unit 4 side. The inlet side cold water pipe 6 is provided with a valve V4, a valve V5, a strainer 12, and a valve V6 in order from the collecting portion 5 to the refrigerator 1 side.

  A flushing water purification device 21 is provided between the outlet side cold water pipe 3 and the inlet side cold water pipe 6 in parallel with the refrigerator 1. That is, a branch pipe 22 serving as a water intake pipe is connected between the valve V4 and the valve V5 in the inlet side cold water pipe 6, and a junction serving as a return pipe is connected between the valve V2 and the valve V3 in the outlet side cold water pipe 3. A flushing water purification device 21 is installed between the branch pipe 22 and the merge pipe 23 so as to connect the pipe 23. The branch pipe 22 and the merge pipe 23 are provided with valves V7 and V8, respectively.

  As shown in FIG. 2, the flushing water purification device 21 sequentially stores raw water flowing in from the branch pipe 22 in order from the upstream side. The fresh water from the 1st sedimentation tank 51, the 2nd sedimentation tank 52, the 1st sedimentation tank 51, and the 2nd sedimentation tank 52 which carries out precipitation separation of the reaction tank 41 and the water from the reaction tank 41 to be processed is collected and stored. A treated water tank 61, a first settling tank 51, and a sludge storage tank 71 for storing sludge (waste) from the second settling tank 52.

  As shown in FIG. 2, the raw water tank 31 maintains a quantity of flushing water flowing from the branch pipe 22 and sends it to the downstream reaction tank 41 while maintaining a constant water level mechanism (for example, a ball tap device). 32, and a certain amount of flushing water is stored in the tank. The raw water tank 31 has a turbidimeter 33 for measuring the turbidity of flushing water in the tank, and the turbidity detected by the turbidimeter is output to a control device (not shown). ing. The pump 35 that takes out the flushing water in the raw water tank 31 and transfers it to the reaction tank 41 is set to a certain amount of water suitable for each precipitation treatment capacity of the first precipitation tank 51 and the second precipitation tank 52 and is operated. The The raw water tank 31 is configured to be airtight, and the gas phase portion in the tank can be decompressed by a vacuum deaeration pump 37.

  The water in the raw water tank 31 taken by the pump 35 is sent to the reaction tank 41. The reaction tank 41 is divided into four regions, a first region 41a, a second region 41b, a third region 41c, and a fourth region 41d by partition walls 42, 43, and 44 that are alternately arranged in a staggered manner when viewed from the side. ing. The partition walls 42, 43, 44 act as a weir so that the water flow passes through the lower end or the upper end thereof, so that the flow path in the reaction tank 41 is formed in a meandering shape when viewed from the side surface. The flushing water is surely flowed into and passed through the installed area, and the treatment efficiency is improved by thoroughly stirring the chemical (described later) and the flushing water that are put into the area.

  In the first region 41a, pH adjustment is performed on the flushed water taken. The pH adjustment is performed by supplying a pH adjuster, for example, sodium hydroxide (NaOH), into the first region 41a from the pH adjuster supply source 81 by the pump 82. The input amount of the pH adjusting agent is controlled by the control device 84 based on the pH value by the pH measuring device 83 provided in the fourth region 41d. For example, the pH is set to 8.5 to 11.0. The operation of the pump 82 is controlled. As the pH adjusting agent (alkali), a known alkaline agent can be used in addition to sodium hydroxide (NaOH).

  The flushing water after the pH adjustment in the first region 41a is then subjected to a condensation treatment in the second region 41b. The second region 41b is supplied with a coagulant from a coagulant supply source 85 by a pump 86, and is stirred by a stirring blade 45 provided in the second region 41b. As the coagulant, a known coagulant such as an inorganic coagulant can be used.

  The flushing water subjected to the condensation treatment in the second region 41b is subjected to the aggregation treatment in the third region 41c. For example, a polymer flocculant is supplied to the third region 41 c from the flocculant supply source 87 by the pump 88 and stirred by the stirring blade 46. The flushing water after the aggregation treatment in the third region 41c is sent to the fourth region 41d, where it is subjected to the aggregation reaction treatment while being stirred by the stirring blade 47.

  The flushing water after the treatment in the fourth reaction tank 41 d is transferred to the first precipitation tank 51 and the second precipitation tank 52 through the pipes 53 and 54. In this embodiment, the first settling tank 51 and the second settling tank 52 which are two settling tanks are provided in parallel, and only one settling tank is used by opening and closing a valve depending on the amount of water to be processed. It is possible to appropriately switch between using two precipitation tanks. It is not always necessary to install two precipitation tanks, and one precipitation tank may be used. The supernatant water (fresh water) cleaned in the first sedimentation tank 51 and the second sedimentation tank 52 is sent to the treated water tank 61 through the pipes 55 and 56. Then, the flushing water in the treated water tank 61 is sent to the merging pipe 23 by the pump 62. The pump 62 is controlled based on the measured value of the water level meter 63 that measures the water level in the treated water tank 61 (specifically, the water level in the treated water tank 61 does not become below a predetermined level).

  The turbidity of the water in the treated water tank 61 is sequentially measured by the turbidimeter 64, and the measurement result is output to a control device (not shown) in the same manner as the turbidimeter 33 of the raw water tank 31. The control device adjusts the input amounts of the coagulant and the flocculant based on at least one of the measured values. The function of the control device may be added to the control device 84. That is, the control device 84 may comprehensively control the pH control, the coagulant and the flocculant input amount.

  On the other hand, the sediment (sludge) precipitated in the first sedimentation tank 51 and the second sedimentation tank 52 is sent to the sludge storage tank 71. The supernatant water in the sludge storage tank 71 can be transferred to the raw water tank 31 through the pipe 73 by the pump 72. In the sludge storage tank 71, the sludge further sinks and the supernatant is generated while it is stored for a long time. However, this supernatant contains a small amount of pollutants that are difficult to settle. Therefore, as described above, by transferring to the raw water tank 31 and reprocessing, the amount of drainage discharged out of the system can be further reduced.

Between the raw water tank 31 and the treated water tank 61, a bypass pipe 91 that bypasses the reaction tank 41, the first precipitation tank 51, and the second precipitation tank 52 is constructed. A filter 92 of the formula is provided. The filter 92 can remove contaminants (for example, turbidity components including zinc) in the flushing water, and the water in the raw water tank 31 is converted into the reaction tank 41, the first settling tank 51, and the second settling tank. When the degree of contamination is such that the treatment at 52 is not necessary, it can be treated by the filter 92 in the bypass pipe 91 and transferred to the treated water tank 61. When switching and operating to flow through the bypass pipe 91, the pump 35 is manually set (for example, the rotation speed) so that the flow rate is suitable for the specifications of the filter 92. The flow rate may be adjusted by the opening degree of the valve 93.

  The processing system according to the present embodiment has the above-described configuration. The pump 2 is activated, the valves V1 to V8 are opened, and the outgoing pipes As, Bs, Cs of the piping systems A, B, C are provided. , Return pipes Ar, Br, Cr, fume and welding debris generated during welding by continuously circulating water in each of the inlet side cold water pipe 6 and outlet side cold water pipe 3 before and after the refrigerator 1 Etc. can be flushed. At the same time, part of the circulating water (flushing water) is introduced from the branch pipe 22 into the flushing water purifier 21, pH treatment, condensation treatment, agglomeration treatment in the reaction tank 41, and further the first precipitation tank. 51, this can be purified through the precipitation process in the second settling tank 52, and the purified supernatant water can be returned to the piping system from the merging pipe 23 again.

  The flushing water circulating in the piping system by such treatment is gradually purified, and when it reaches a predetermined clean level (the index value can be either turbidity or zinc concentration), the flushing water purifier 21 The process at is finished. And only the sludge which is aggregates, such as zinc stored in the sludge storage tank 71, and a turbidity component, welding waste, is discharged | emitted out of a piping system by this process, and these sludge is sludge as industrial waste. What is necessary is just to make it discharge | emit from the storage tank 71, and to process after that, for example by a specialized processor. Therefore, flushing water that has been drained outside the system after the conventional flushing treatment can be purified on-site without draining at all, and turbidity components containing harmful zinc must be removed separately as sludge. Is possible.

  In the above embodiment, fine zinc particles that are difficult to settle and dissolved zinc ions are coagulated and settled in the first sedimentation tank 51 and the second sedimentation tank 52 through the coagulation process and the coagulation process in the reaction tank 41, and fresh water. It is possible to separate into sludge and settled sludge.

  In this case, as described above, the vacuum deaeration pump 37 is connected to the raw water tank 31, and the gas phase portion in the raw water tank 31 is, for example, 5 kPa or more lower than the atmospheric pressure (10 kPa to 90 kPa). It is possible to reduce the pressure. Accordingly, by performing degassing under reduced pressure in the raw water tank 31, minute bubbles present in the flushing water are increased before flowing into the reaction tank 41 to promote discharge, and the vacuum deaeration pump 37 is promptly increased. Can be removed through. As a result, it is possible to suppress a situation in which a part of the aggregate that should be separated by settling is combined with minute bubbles and floated and separated to the surface layer in the first settling tank 51 and the second settling tank 52 that perform the precipitation process. Then, it is possible to take the supernatant water (fresh water) in the first sedimentation tank 51 and the second sedimentation tank 52 and return it to the piping system again through the treated water tank 61. The raw water tank 31 may be provided with a barometer (vacuum gauge) so that the pressure value in the gas phase portion in the tank can be visually observed. Moreover, you may control the vacuum deaeration pump 37 so that it may become a predetermined pressure.

  Depending on the pH value of the flushing water, the dissolved zinc concentration may be high, but in this case, it is dissolved by adjusting the pH by adding a pH adjusting agent in the raw water tank 31 as necessary. It is also possible to promote the precipitation (fine particleization) of the zinc that is being removed and to remove it by the subsequent agglomeration treatment. If the pH value of the flushing water after treatment is not appropriate as the pH value to be returned to the piping system by adding a flocculant or controlling the pH of raw water, a function of adjusting pH in the treated water tank 61 may be added. .

  When the deaeration process is performed in the raw water tank 31, it is expected that the size of the raw water tank 31 cannot be increased due to restrictions such as the installation location. In such a case, since the residence time of the flushing water in the raw water tank 31 is short, it may be considered that the deaeration treatment cannot be sufficiently performed. In such a case, for example, a countermeasure example as shown in FIG. 3 can be proposed.

  In this example, the inflow port 22a is formed by extending the branch pipe 22 into the tank and immersing the lower end below the surface of the water so that the inflow portion of the flushing water flowing from the branch pipe 22 is the lower part in the tank. It is set at the bottom of the tank. And the outflow port 31a which flows out from the raw | natural water tank 31 to the reaction tank 41 of the next process is set in the tank downward direction. At the same time, a vertical plate 101 is vertically installed between the inflow port 22a and the outflow port 31a so that the lower end is in contact with the tank bottom and the top 101a is located below the water surface.

  As a result, the flushing water flowing into the raw water tank 31 from the inlet 22 a once flows over the top 101 a of the vertical plate 101 and then flows into the outlet 31 a, and the flowing flushing water flows into the raw water tank 31. And once it will always flow through the surface layer. As a result, the bubbles degassed by the vacuum degassing pump 37 can be more reliably discharged into the gas phase, and the aggregate sedimentation in the first sedimentation tank 51 and the second sedimentation tank 52 is more reliably performed. And the tank size can be reduced.

  In the example shown in FIG. 4, the flow path is made longer than in the example of FIG. 3 to improve the deaeration performance. That is, in the example shown in FIG. 4, in addition to the vertical plate 101 shown in FIG. 3, the top portion 102 a is located on the water surface, and the vertical plate 102 having the communication portion 102 b below and the vertical plate 101, The top portion 102a further includes a vertical plate 103 positioned below the water surface. That is, these vertical plates 101, 102, and 103 are alternately arranged in a staggered manner as viewed from the side. As a result, the flow path when the flushing water flows from the inlet 22a to the outlet 31a is made longer than the example of FIG. 3, and when the top 101a of the vertical plate 101 and the top 103a of the vertical plate 103 are exceeded. It can be made to flow in the surface layer part in a tank at two places. Thereby, the deaeration efficiency is further improved as compared with the example of FIG. Moreover, if it is the same water quantity, the tank size of the raw | natural water tank 31 can be made compact rather than the case where it simply deaerates.

  In the example of FIGS. 3 and 4, the vertical plate 101 and the like are vertically installed in the tank of the raw water tank 31, but instead of this, as shown in FIG. You may make it install in. In the example of FIG. 5, the inlet 22 a from the branch pipe 22 is located on the water surface in the raw water tank 31, and two inclined plates 111 and 112 are provided below the water surface. The inclined plate 111 has one end 111 a fixed to the side wall of the raw water tank 31, the other end 111 b extending obliquely upward and positioned below the water surface, and the other end 111 b and the other side wall of the raw water tank 31. The space between them forms a flow path 113.

  The other inclined plate 112 is fixed to the other side wall of the raw water tank 31 so that one end 112a thereof is located above the outlet 31a of the raw water tank 31, and the other end 112b extends obliquely upward, It is located near the lower part of the base of the inclined plate 111. A space between the other end 112 b and the side wall of the raw water tank 31 forms a flow path 114.

  By providing the inclined plates 111 and 112 in this manner, the flushing water that has flowed into the raw water tank 31 from the inlet 22a flows as shown by the arrows in FIG. The degassing bubbles can be removed more easily than in the example of FIG. In other words, if the amount of water is the same, the tank size of the raw water tank 31 can be made more compact than when simply degassing. By providing the inclined plates 111 and 112, the deaerated bubbles can be quickly captured on the lower surfaces of the inclined plates 111 and 112. The deaerated bubbles that have reached the lower surfaces of the inclined plates 111 and 112 move upward along the lower surface, reach the water surface, and are removed. Thereby, the risk that degassing bubbles (especially bubbles generated on the downstream side in the tank) flow out of the tank from the outlet 31a due to turbulent flow or the suction force of the pump 35 can be reduced. In addition, a large number of air bubbles that have reached the lower surfaces of the inclined plates 111 and 112 are gathered to form large air bubbles, which makes it less susceptible to the influence of the water flow.

  In the operation example of the above-described system, the pump 2 is activated and the valves V1 to V8 are opened, and the outgoing pipes As, Bs, Cs of the piping systems A, B, C, the return pipes Ar, Br, Cr and the pipes before and after the refrigerator 1 are continuously fed and circulated to circulate the flushing water. Instead, the pump 2 is stopped, the valves V2 and V5 are closed, The flushing water may be purified by the flushing water purification device 21 using the pumps 35 and 62.

  INDUSTRIAL APPLICABILITY The present invention is useful for the treatment of flushing water that flows in a piping system of equipment in which galvanized steel pipes are piped.

DESCRIPTION OF SYMBOLS 1 Refrigerator 2 Pump 3 Outlet side cold water piping 6 Inlet side cold water piping 21 Flushing water purification apparatus 22 Branch piping 22a Inflow part 23 Merged pipe 31 Raw water tank 31a Outflow part 32 Constant water level mechanism 33 Turbidimeter 35 Pump 37 Vacuum deaeration pump 41 Reaction tank 41a 1st area | region 41b 2nd area | region 41c 3rd area | region 41d 4th area | region 45, 46, 47 Stirring blade 51 1st sedimentation tank 52 2nd sedimentation tank 61 Treated water tank 64 Turbidimeter 71 Sludge storage tank 81 pH adjustment Agent supply source 83 pH measuring device 84 Control device 85 Coagulant supply source 87 Coagulant supply source A, B, C Piping system As, Bs, Cs Outward piping Ar, Br, Cr Return piping Piping V1-V8 Valve V

Claims (7)

In the method of flushing by flowing water through the equipment piping,
Part or all of the flushing water flowing through the pipe during the flushing treatment is taken out, and the taken out flushing water is passed through the raw water tank whose pressure in the gas phase in the tank is lower than the atmospheric pressure, and then from the raw water tank. Condensation treatment and coagulation treatment are performed on
A flushing treatment method comprising: precipitating agglomerates in flushed water after treatment, and then returning clean supernatant water to the pipe. The flushing processing method according to claim 1, wherein the pressure in the gas phase part in the raw water tank is reduced to 5 kPa or more lower than the atmospheric pressure. A flushing water treatment system for use in carrying out the flushing treatment method according to claim 1 or 2,
Purifying flushing water taken from the pipe, and having a flushing water purification device connected in parallel with the pipe so as to return the flushed water after purification to the pipe,
The flushing water purifier is
A raw water tank, a reaction tank in which a coagulant and a flocculant are sequentially added to the water from the raw water tank, and a precipitation tank for precipitating agglomerates contained in the water from the reaction tank,
A flushing water treatment system, wherein a pump for decompressing a gas phase portion in the tank is connected to the raw water tank. The raw water tank rectifies the water flow of the flushing water so that it flows near the water surface at least once while the flushing water flows from the inflow part of the flushing water to the outflow part of the reaction tank. The flushing water treatment system according to claim 3, wherein a rectifying mechanism is provided between the inflow portion and the outflow portion. The rectifying mechanism is a plate body provided in a vertical direction in a tank, wherein the inflow portion is set at a lower side in the tank, and the outflow portion is set at a lower side in the tank. 5. The flushing water treatment system according to 4. The rectifying mechanism is a plate body that extends obliquely upward from the inner wall of the tank in the tank, the inflow portion is set in the upper portion of the tank on the base side of the plate body, and the outflow portion is set in the lower portion of the tank. The flushing water treatment system according to claim 4, wherein the flushing water treatment system is provided. The flushing water treatment system according to claim 4 or 5, wherein a plurality of said plate bodies are provided.

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