Oil-containing wastewater purification system

Abstract

To provide a purification system of oil-containing waste water for purification of the oil-containing waste water in an oil-containing waste water holding part provided in a building.SOLUTION: A purification system 21 of oil-containing waste water includes: a facility which is accommodated in a building and uses water pumped up from an outside intake source; a membrane filtration apparatus 25 which filters the water pumped up from the intake source and sends it to the facility; an oil-containing waste water holding part 23 which is provided in the building for holding the oil-containing waste water; piping which supplies the oil-containing waste water in the oil-containing waste water holding part 23 to the membrane filtration apparatus 25; and piping which drains treated water obtained by treating the oil-containing waste water by the membrane filtration apparatus 25.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a purification system for oil-containing wastewater. [Background technology]

[0002] In hydroelectric power plants, when equipment such as pumps that contain oils such as hydraulic oil and lubricating oil required for operation and operation (hereinafter referred to as oil-impregnating equipment) are flooded, oil-impregnating wastewater may be generated when water comes into contact with the oil-impregnating equipment. Patent Document 1 discloses a floating oil recovery system for a power plant that recovers oil that floats on the water surface of the drainage pit of the power plant. The floating oil recovery system for a power plant is equipped with a blowing means that guides exhaust air from the generator to the drainage pit side and collects the floating oil at a predetermined position in the drainage pit, and an extraction means that is provided at a predetermined position in the drainage pit and removes the collected floating oil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-020086 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a trend toward increased precipitation from typhoons and heavy rains due to climate change, making buildings more susceptible to flooding. Rainwater that enters a building can be drained outside the building using the building's drainage system, but if rainwater comes into contact with oil-containing equipment and becomes oil-containing wastewater, it cannot be drained directly outside the building and may need to be treated as industrial waste.

[0005] An object of the present invention is to provide a purification system for oil-containing wastewater that purifies oil-containing wastewater in an oil-containing wastewater storage section provided within a building. [Means for solving the problem]

[0006] The oil-containing wastewater purification system of the present invention comprises equipment housed in a building that uses water pumped from an external water intake source, a membrane filtration device that filters the water pumped from the water intake source and sends it to the equipment, an oil-containing wastewater holding section provided within the building that holds the oil-containing wastewater, piping that supplies the oil-containing wastewater in the oil-containing wastewater holding section to the membrane filtration device, and piping that discharges treated water obtained by treating the oil-containing wastewater in the membrane filtration device. Effect of the Invention

[0007] According to the present invention, it is possible to provide a purification system for oil-containing wastewater that purifies oil-containing wastewater in an oil-containing wastewater holding section provided within a building. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a hydroelectric power generation system according to a first embodiment of the present invention, showing a state in a normal operation mode. [Diagram 2] FIG. 2 is a diagram showing the state of an oil-free wastewater water supply mode in the hydroelectric power generation system shown in FIG. [Diagram 3] FIG. 2 is a diagram showing the state of an oil-containing wastewater treatment mode in the hydroelectric power generation system shown in FIG. [Figure 4] FIG. 11 is a schematic configuration diagram of a hydroelectric power generation system according to a second embodiment of the present invention, showing a state in a normal operation mode. [Diagram 5] FIG. 5 is a diagram showing the state of the oil-free wastewater water supply mode in the hydroelectric power generation system shown in FIG. [Figure 6] FIG. 5 is a diagram showing the state of the hydraulic power generation system shown in FIG. 4 in an oil-containing wastewater treatment mode. [Figure 7] FIG. 1 is a schematic diagram of a portable membrane filtration device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) Hereinafter, the oil-containing wastewater purification system according to some embodiments of the present invention will be described with reference to the drawings. Figures 1 to 3 show the schematic configuration of a hydroelectric power generation system 1 and an oil-containing wastewater purification system 21 provided in the hydroelectric power generation system 1. In each figure, the shaded areas indicate the areas through which river water or cooling water flows. Figure 1 shows the state during normal operation, Figure 2 shows the state during non-oil-containing wastewater transport, and Figure 3 shows the state during oil-containing wastewater treatment.

[0010] The hydroelectric power generation system 1 has a hydraulic turbine generator 2 equipped with a runner 3 and a generator 4. The runner 3 is housed in a casing 5 connected to a penstock 6. A main shaft 7 is attached to the runner 3, and the main shaft 7 penetrates the casing 5. The upper end of the main shaft 7 is connected to the generator 4 via a coupling (not shown). River water supplied from the penstock 6 rotates the runner 3, and electricity is generated by the generator 4. The penstock 6 is provided with an inlet valve 8 for stopping the supply of river water during maintenance of the hydraulic turbine generator 2. The lower end of the casing 5 is connected to a discharge pipe 9, and the river water that has rotated the runner 3 is discharged into a river or the like through the discharge pipe 9. The tip of the water intake pipe L1 opens upstream of the inlet valve 8 of the penstock 6. The tip is provided with a water intake port 28 equipped with a filter to remove foreign matter. The water intake pipe L1 takes in cooling water to be supplied to the generator 4 and a bearing unit 11 (described later), and seal water to be supplied to a seal unit 14 (described later). The water intake pipe L1 is connected to a membrane filtration device 25 (described later). A first valve V1 is provided in the water intake pipe L1. The water intake pipe L1 may be connected to a discharge pipe 9 or any water source other than river water.

[0011] The main shaft 7 is provided with an upper bearing 11a, a lower bearing 11b, and a water turbine bearing 11c (hereinafter, collectively referred to as the bearing section 11) from top to bottom. The generator 4 and the bearing section 11 are provided with a coiled tube 12, and the generator 4 and the bearing section 11 are cooled by passing cooling water through the coiled tube 12. A seal section 14 that seals the penetration section 13 of the main shaft 7 in the casing 5 is provided below the water turbine bearing 11c. The seal section 14 has a bearing water tank 15 and a shaft seal section 16 provided at the penetration section 13 of the main shaft 7 in the bearing water tank 15. The bearing water tank 15 is filled with seal water. A submerged bearing 17 is housed inside the bearing water tank 15, and the submerged bearing 17 is lubricated and cooled by the seal water. The main shaft 7, the bearing section 11, and the seal section 14 are some of the components of the water turbine generator 2.

[0012] The main equipment of the hydroelectric power generation system 1, including the water turbine generator 2, is housed in a building 22. The structure of the building 22 is not particularly limited, but the building 22 in this embodiment has a ground floor and a basement floor. A drainage pit 23 is provided on each floor to drain non-oil-containing wastewater generated in the building 22 due to the intrusion of rainwater, etc. The drainage pit 23 is dug from the general surface of the floor and is the lowest part of each floor. The drainage pit 23 is provided on the floor surface 24 of the building 22, and also functions as an oil-containing wastewater storage section 23 that stores oil-containing wastewater generated by leakage from oil-containing equipment or flooding of oil-containing equipment. In other words, when the oil-containing wastewater is treated, the oil-containing wastewater is collected in the drainage pit 23. As long as it is possible to collect non-oil-containing wastewater and oil-containing wastewater, the drainage pit 23 does not have to have a pit shape, and may have a shape such as a recess. A drain pipe L3 is connected to the drainage pit 23 on each floor, and the drain pipe L3 is connected to a header pipe L4 extending vertically. The header pipe L4 penetrates the building 22 from the basement floor to the ground floor, and the drainage pits 23 installed on each floor are connected to the header pipe L4 by drain pipes L3. A transfer pipe L5 branches off from the header pipe L4. A transfer pump P1 is provided in the transfer pipe L5. The transfer pump P1 is preferably installed on the ground floor to prevent it from being submerged. By providing the header pipe L4, the amount of piping and the number of transfer pumps P1 can be reduced.

[0013] The purification system 21 has a membrane filtration device 25. The membrane filtration device 25 filters cooling water and seal water collected from a river during normal operation, and filters the oil-containing wastewater when treating oil-containing wastewater generated by leakage or flooding of the building 22. The membrane filtration device 25 has a microfiltration membrane module or an ultrafiltration membrane module. Oil-containing wastewater may contain emulsified oil particles with a particle diameter of about 0.1 to 100 μm due to emulsification, and the membrane filtration device 25 has the ability to capture such emulsified oil particles. The membrane filtration device 25 of this embodiment is an immersion type filtration device in which the filtration membrane module is immersed in a tank. As the tank, a storage tank 26 in which cooling water and seal water of the hydroelectric generator 2 are stored is used. Since the storage tank 26 is often provided in the hydroelectric power generation system 1, it is not necessary to provide a new tank when the immersion type membrane filtration device 25 is used.

[0014] The outlet of the membrane filtration device 25 is connected to the filtrate pipe L2. A suction pump P2 is provided in the filtrate pipe L2, and filtration pressure (pressure difference between the inlet and outlet of the membrane filtration device 25) is obtained by suction with the suction pump P2. A pressurized membrane filtration device 25 may be used instead of the immersion type. In the case of the pressurized type, a pump is provided upstream of the membrane filtration device 25, and the filtration pressure is obtained by the pressurized force of the pump. The filtration membrane of the membrane filtration device 25 is preferably hydrophilic. Examples of the material include PTFE (polytetrafluoroethylene), PES (polyethersulfone), and PAN (polyacrylonitrile). PVDF (polyvinylidene fluoride) is a relatively highly hydrophobic material, but if it is subjected to hydrophilization treatment such as mixing a hydrophilizing material, the main material may be PVDF. A hydrophilic filtration membrane repels oil, so oil is less likely to adhere to the filtration membrane, and the deterioration of filtration performance is suppressed. A second valve V2 is provided before the branching portion of the filtrate water pipe L2 to the seal water supply pipe L6.

[0015] A chemical cleaning means for the membrane filtration device 25 is provided. As the chemical, a mixture of a surfactant, an alkaline agent (e.g., caustic soda, etc.), and sodium hypochlorite is preferably used. When metal components (iron, manganese, aluminum, etc.) are contained at a high concentration, an acid agent (e.g., oxalic acid, citric acid, etc.) is preferably used. The chemical cleaning means has a storage tank 26 or a chemical storage tank 27 connected to the piping on the inlet side or outlet side of the storage tank 26 (in the illustrated example, the chemical storage tank 27 is connected to the storage tank 26). When chemically cleaning the membrane filtration device 25, the storage tank 26 is isolated and the inside of the storage tank 26 is replaced with a chemical. By immersing the filtration membrane in a chemical for a predetermined time, oil and dust attached to the filtration membrane are peeled off and regeneration is performed. It is preferable to perform chemical cleaning as appropriate when the water flow rate of the filtration membrane decreases. In particular, since the filtration membrane is likely to be contaminated with oil after treating oil-containing wastewater, it is preferable to perform chemical cleaning before returning to normal operation.

[0016] A seal water supply pipe L6 branches off from the filtrate water pipe L2 to supply seal water to the seal unit 14. The water pressure of the river water flowing into the casing 5 acts on the shaft seal unit 16. Therefore, high-pressure seal water is supplied to the seal unit 14 to prevent or suppress the river water from flowing from the shaft seal unit 16 into the seal unit 14. The seal water gradually leaks from the shaft seal unit 16 and flows out into the casing 5, and is finally discharged into the river. The seal water supply pipe L6 compensates for the seal water lost in the seal unit 14. The end of the filtrate water pipe L2 is connected to a cooling water supply pipe L7 that supplies cooling water to the generator 4 and the bearing unit 11. After cooling the generator 4 and the bearing unit 11, the cooling water is discharged into the river.

[0017] A drain pipe L8 branches off from the filtrate water pipe L2 between the membrane filtration device 25 and the branching point of the seal water supply pipe L6. The drain pipe L8 is connected to a water outlet 29. The water outlet 29 constitutes a means for discharging treated oil-containing wastewater and non-oil-containing wastewater. A second valve V2 is provided between the branching point of the drain pipe L8 of the filtrate water pipe L2 and the branching point of the seal water supply pipe L6. A third valve V3 is provided between the branching point of the drain pipe L8 from the filtrate water pipe L2 and the junction of the flow path switching pipe L9 (described later).

[0018] The transfer pipe L5 is connected to the flow path switching pipe L9. One end of the flow path switching pipe L9 is connected to the water intake pipe L1, and the other end is connected to the drain pipe L8. A fourth valve V4 is provided between the connection of the flow path switching pipe L9 to the transfer pipe L5 and the junction with the water intake pipe L1. A fifth valve V5 is provided between the connection of the flow path switching pipe L9 to the transfer pipe L5 and the junction with the drain pipe L8.

[0019] Next, each operation mode of the purification system 21 will be described with reference to Figs. 1 to 3. Fig. 1 shows the normal operation mode, in which the first and second valves V1 and V2 are open and the third to fifth valves V3 to V5 are closed. Cooling water and seal water are taken in from the intake pipe L1, filtered by the membrane filtration device 25, and supplied to the generator 4, the bearing unit 11, and the seal unit 14 through the cooling water supply pipe L7 and the seal water supply pipe L6. The cooling water and seal water are discharged into the river. Referring to Fig. 2, in the normal operation mode shown in Fig. 1, the fifth valve V5 is opened and the transfer pump P1 is started (non-oil-containing wastewater water supply mode). For example, if rainwater has entered the building 22 but is not contaminated with oil, the rainwater (non-oil-containing wastewater) accumulated in the drainage pit 23 can be discharged into the river while continuing to operate the water turbine generator 2. Rainwater accumulated in the drainage pit 23 passes through the drain pipe L3, the header pipe L4, the transfer pipe L5, the flow path switching pipe L9, and the drainage pipe L8, and is discharged from the water outlet 29. The discharge of non-oil-containing wastewater is performed independently of the supply of cooling water and seal water, so the supply of cooling water and seal water is not affected in any way.

[0020] Next, the oil-containing wastewater treatment mode will be described. Possible causes of oil-containing wastewater include water leakage and flooding. Water leakage is a phenomenon in which oil-containing equipment (pumps, tanks, piping, valves, etc.) installed inside the building 22 leaks out. This phenomenon can occur when the oil-containing equipment comes into contact with rainwater, river water, groundwater, etc. that has entered the building 22 from the outside, but it can also occur when the oil-containing equipment itself deteriorates or is damaged. In the former case, not only oil but also rainwater that has come into contact with oil becomes oil-containing wastewater. Flooding is a phenomenon in which oil-containing wastewater enters the building 22. Due to damage to outdoor tanks, outdoor transformers, etc. on the power plant site, built-in oil or a mixture of built-in oil and rainwater, etc. may enter the building 22.

[0021] For example, when rainwater that has entered the building 22 is contaminated with oil and oil-containing wastewater is generated, the first, second, and fifth valves V1, V2, and V5 are closed and the third and fourth valves V3 and V4 are opened as shown in FIG. 3. The oil-containing wastewater treatment mode can be entered from either the normal operation mode shown in FIG. 1 or the non-oil-containing wastewater water supply mode shown in FIG. 2. When entering the oil-containing wastewater treatment mode from the normal operation mode, the transfer pump P1 is started. In the oil-containing wastewater treatment mode, the operation of the water turbine generator 2 is stopped and the oil-containing wastewater is treated by the membrane filtration device 25. The oil-containing wastewater is collected in the drainage pit 23, and the oil-containing wastewater that has accumulated in the drainage pit 23 is supplied to the membrane filtration device 25 through the drain pipe L3, the header pipe L4, the transfer pipe L5, the flow path switching pipe L9, and the water intake pipe L1. These pipes (the upstream portion of the membrane filtration device 25 among the pipes indicated by the thick lines in FIG. 3) constitute a first pipe connecting the oil-containing wastewater holding section (drainage pit 23) to the membrane filtration device 25. The treated water (filtered water) treated in the membrane filtration device 25 passes through the filtered water pipe L2 and the drainage pipe L8, and is discharged from the discharge outlet 29. These pipes (the downstream portion of the membrane filtration device 25 among the pipes indicated by the thick lines in FIG. 3) constitute a second pipe connecting the membrane filtration device 25 to the discharge equipment. The section of the water intake pipe L1 from the water intake port 28 to the junction with the flow path switching pipe L9 is connected to an external water intake source, and constitutes a third pipe junction with the first pipe. Furthermore, the section of the filtrate water pipe L2 downstream of the branch of the drainage pipe L8 and the cooling water supply pipe L7 branch off from the second pipe and are connected to the object to be cooled (the generator 4, the bearing unit 11) installed in the building 22, forming a fourth pipe that supplies cooling water to the object to be cooled. The transfer pipe L5, the flow path switching pipe L9, and the second to fourth valves V2, V3, and V4 constitute a switching means for switching the first to fourth pipes so as to switch between the normal operation mode and the oil-containing wastewater treatment mode. Comparing FIG. 2 and FIG. 3, in FIG. 2, the oil-free wastewater that does not need to be treated by the membrane filtration device 25 bypasses the filtration device 25, whereas in FIG. 3, the oil-free wastewater that needs to be treated by the membrane filtration device 25 passes through the membrane filtration device 25. Except for this point, the flow of the oil-free wastewater and the oil-containing wastewater is basically the same. In FIG. 3, the filtration pressure of the membrane filtration device 25 is preferably 100 kPa or less.By keeping the filtration pressure low, the amount of oil-containing wastewater leaking from the membrane filtration device 25 to the secondary side (outlet side) can be reduced.

[0022] As described above, according to this embodiment, the oil-containing wastewater can be purified using the membrane filtration device 25 that filters the cooling water and the seal water, so that the addition of equipment can be minimized. When modifying an existing hydroelectric power generation system in which the membrane filtration device 25 is provided, this embodiment can be implemented by simply adding the flow path switching pipe L9. When modifying an existing hydroelectric power generation system in which the membrane filtration device 25, the drain pipe L3, and the header pipe L4 are not provided, this embodiment can be implemented by simply adding the membrane filtration device 25, the drain pipe L3, the header pipe L4, and the flow path switching pipe L9. In the latter case, since the cooling water and the seal water can be filtered by the membrane filtration device 25, clogging of the coiled pipe 12 and the like can also be suppressed.

[0023] Second Embodiment This embodiment differs from the first embodiment in that the cooling water is recycled and the cooling water and the seal water are cooled by a cooling device. Since the other points are the same as those of the first embodiment, please refer to the description of the first embodiment for the common configuration and effects. Figures 4 to 6 correspond to Figures 1 to 3, respectively. The cooling water supply pipe L7 branches off at the inlet side of the generator 4 and the bearing unit 11, merges again at the outlet side, and is connected to the recirculation pipe L10. The recirculation pipe L10 merges with the filtrate water pipe L2 upstream of the branch point of the seal water supply pipe L6 from the filtrate water pipe L2. The position where the recirculation pipe L10 merges with the filtrate water pipe L2 may be either upstream or downstream of the drainage pipe L8. A sixth valve V6 is provided near the merger of the recirculation pipe L10 with the filtrate water pipe L2. The cooling water for the generator 4 and the bearing unit 11 is reused through the recirculation pipe L10. On the other hand, the seal water is discharged into a river and is not reused, as in the first embodiment. Therefore, water is taken from the water intake pipe L1 at a flow rate equivalent to the seal water leaking from the bearing 16. Because the flow rate of the seal water leaking from the bearing 16 is small, the flow rate of water taken from the river is not very large. If the cooling water cannot be circulated for some reason, the cooling water may be discharged by switching to the drainage pipe L12 branching off from the recirculation pipe L10 (a valve for switching is not shown).

[0024] The recirculation pipe L10 is provided with a cooling device 30 and a transfer pump P3 for cooling water. The cooling device 30 can be configured, for example, as a heat pump. The heat pump can easily produce low-temperature cooling water. This allows the flow rate of the cooling water flowing through the cooling water supply pipe L7 and the recirculation pipe L10 to be reduced, making it possible to reduce the diameter of these pipes, the flow rate of the cooling water, and the size and installation space of the membrane filtration device 25. The heat taken from the cooling water by the heat pump can be used for heat supply within the power plant (not shown) as well as heat supply outside the power plant (not shown). Examples of heat supply within the power plant include hot water supply, heating, and snow melting on the premises. Examples of heat supply outside the power plant include hot water supply, heating, snow melting, and other uses, but are not limited to these.

[0025] A return pipe L11 is provided to return a portion of the filtered water from the filtrate pipe L2 to the intake pipe L1. The return pipe L11 branches off from the filtrate pipe L2 downstream of the junction of the recirculation pipe L10 with the filtrate pipe L2. The return pipe L11 branches off from the filtrate pipe L2 upstream of the junction of the drainage pipe L8 with the filtrate pipe L2, but may branch off from the filtrate pipe L2 downstream of the junction. The return pipe L11 may branch off from the circulation pipe L10. A seventh valve V7 is provided in the return pipe L11. The cooling water has a high degree of cleanliness due to repeated treatment with the membrane filtration device 25, so it is not necessary to treat the entire amount of the cooling water with the membrane filtration device 25 each time. However, the content of iron crud and the like may gradually increase during circulation through the circulation path, so a portion of the cooling water is treated with the membrane filtration device 25. The entire amount of water taken from the river is treated with the membrane filtration device 25.

[0026] Next, each operation mode of the purification system 21 will be described with reference to Figs. 4 to 6. Fig. 4 shows the normal operation mode, in which the first, second, sixth, and seventh valves V1, V2, V6, and V7 are open, and the third to fifth valves V3 to V5 are closed. The cooling water and the seal water are taken in from the intake pipe L1, filtered by the membrane filtration device 25, and supplied to the generator 4, the bearing unit 11, and the seal unit 14. The cooling water passes through the recirculation pipe L10, is cooled by the cooling device 30, and is supplied to the generator 4, the bearing unit 11, and the seal unit 14. A part of the cooling water passes through the return pipe L11 and is filtered by the membrane filtration device 25. The seal water is discharged into the river. Referring to Fig. 5, in the normal operation mode shown in Fig. 4, the fifth valve V5 is opened, and the transfer pump P1 is started (oil-free wastewater water supply mode). The state shown in Fig. 5 is the same as the state shown in Fig. 2.

[0027] Referring to FIG. 6, the first, second, fifth to seventh valves V1, V2, V5 to V7 are closed, and the third and fourth valves V3, V4 are opened (oil-containing wastewater treatment mode). The state shown in FIG. 6 is the same as the state shown in FIG. 3. The drain pipe L3, the header pipe L4, the transfer pipe L5, the flow path switching pipe L9, and the water intake pipe L1 (the upstream part of the membrane filtration device 25 among the pipes shown by the thick lines in FIG. 6) constitute a first pipe connecting the oil-containing wastewater holding section (the drainage pit 23) to the membrane filtration device 25. The filtrate pipe L2 and the drainage pipe L8 (the downstream part of the membrane filtration device 25 among the pipes shown by the thick lines in FIG. 6) constitute a second pipe connecting the membrane filtration device 25 to the water discharge facility. The section of the water intake pipe L1 from the water intake port 28 to the junction with the flow path switching pipe L9 is connected to an external water intake source, and constitutes a third pipe junction with the first pipe. Furthermore, the section of the filtered water pipe L2 downstream of the branch point of the drainage pipe L8 and the cooling water supply pipe L7 branch off from the second pipe and are connected to the object to be cooled (the generator 4, the bearing 11) installed in the building 22, forming a fourth pipe that supplies cooling water to the object to be cooled. Furthermore, the part of the cooling water supply pipe L7 downstream of the outlet of the object to be cooled (the generator 4, the bearing 11) and the recirculation pipe L10 form a circulation flow path of the cooling water together with the first pipe, the second pipe, and the fourth pipe. The circulation flow path of the cooling water is connected to the cooling water outlet of the object to be cooled and returns to the cooling water inlet of the object to be cooled.

[0028] Although the oil-containing wastewater purification system 21 of the present invention has been described above by way of embodiments, the present invention is not limited to these embodiments. As an example, the membrane filtration device may be portable. FIG. 7 shows the configuration of a portable membrane filtration device 41. The bold lines in FIG. 7(a) indicate the flow of water during normal operation, and the bold lines in FIG. 7(b) indicate the flow of water during backwashing. Normal operation and backwashing operation are switched by a valve not shown. The membrane filtration device 41 has a microfiltration membrane module or an ultrafiltration membrane module (hereinafter referred to as a membrane module 42), a transfer pump 43 that supplies oil-containing wastewater to the membrane module 42, a filtrate water tank 44 that stores the filtrate water treated by the membrane module 42, and a water supply / backwash pump 45. The filtrate water tank 44 and the water supply / backwash pump 45 constitute a backwashing facility 46 that backwashes the membrane module 42. These facilities 41 to 46 are unitized inside a housing 47. The housing 47 can be transported by a truck or the like using a hanging jig (not shown) provided at the top of the housing 47. The oil-containing wastewater supply port 48, the treated water discharge port 49, and the backwash water discharge port 50 are provided on the same side of the housing 47 so that pipes can be connected from the outside and the housing 47 can be operated even when it is housed in a truck. During normal operation, the oil-containing wastewater is supplied from the supply port 48, pressurized by the transfer pump 43, and supplied to the membrane module 42 in an upward flow. The treated water (filtrate) treated in the membrane module 42 is stored in the filtrate tank 44 and discharged from the discharge port 49 by the water supply / backwash pump 45. In addition, an oil detector may be provided in the filtrate tank 44, and if oil is detected in the filtrate, the filtrate may be further sent to the membrane module 42 through a switching line (not shown). The switching line is preferably provided on the same side of the housing 47 as the supply port 48, the discharge port 49, and the discharge port 50. During backwashing, filtered water (backwash water) stored in the filtered water tank 44 is pressurized by the water supply / backwash pump 45 and supplied in a downward flow to the membrane module 42. The used backwash water is discharged from a discharge outlet 50. A pump for supplying filtered water to the discharge outlet 49 and a pump for supplying backwash water to the membrane module 42 may be provided separately. The membrane filtration device 41 can be used as an alternative facility to the storage tank 26, the membrane filtration device 25, and the chemical storage tank 27 of the first and second embodiments.When the generation of oil-containing wastewater is expected due to flooding of the building 22, etc., a portable filtration device 41 can be installed in advance at the position of the storage tank 26 in Figures 1 to 6 to prepare for the generation of oil-containing wastewater. Even after the basement floor of the building 22 is flooded, the filtration device 41 is installed above ground, so it can be transported and installed without great difficulty. The portable membrane filtration device 41 can be shared by multiple hydroelectric power generation systems, making it possible to reduce costs.

[0029] The present invention can be used to retrofit existing hydroelectric power generation systems. The piping and equipment to be added depends on the existing piping and equipment, but as mentioned above, the membrane filtration devices 25, 41 can be used in common for both oil-free and oil-containing wastewater, so the equipment to be added is limited. It is also possible to provide separate filtration equipment for oil-free and oil-containing wastewater.

[0030] The present invention is preferably applicable to the treatment of oil-containing wastewater generated inside the building 22, but can also be applied to oil-containing wastewater generated outdoors, for example, when oil leaks from oil-containing equipment such as pumps, tanks, and piping installed outdoors, generating oil-containing wastewater outdoors. In other words, the present invention can be used to treat oil-containing wastewater inside and outdoors the building 22, and can be applied to various facilities of a hydroelectric power plant. The present invention can also be used for purposes other than hydroelectric power generation systems. In other words, the object to be cooled is not limited to hydroelectric generators, and may be any oil-containing equipment containing hydraulic oil or lubricating oil. [Explanation of symbols]

[0031] 1. Hydroelectric Power System 2. Hydroelectric generator 21 Purification System 22 Building 23 Oil-containing drainage holding part (drainage pit) 25 Membrane filtration equipment 26 Reservoir 27 Chemical cleaning methods 29 Water discharge facility (water outlet) 41 Portable membrane filtration equipment L1 Water intake pipe L2 Filtered water piping L3 Drain pipe L4 Header piping L5 Transfer piping L6 Seal water supply pipe L7 Cooling water supply piping L8 Drain piping L9 Flow path switching piping L10 Recirculation piping L11 Circulation pipe L12 Drain piping

Claims

1. Facilities housed in buildings that use water pumped from an external water source; A membrane filtration device that filters water pumped from the water intake source and sends the water to the facility; An oil-containing wastewater storage unit provided in the building and configured to store oil-containing wastewater; A pipe that supplies the oil-containing wastewater in the oil-containing wastewater holding unit to the membrane filtration device; A pipe for discharging treated water obtained by treating the oil-containing wastewater with the membrane filtration device; A purification system for oil-containing wastewater.

2. Further comprising a storage tank for storing water pumped from the water intake source, The purification system according to claim 1 , wherein the membrane filtration device is immersed in the water in the storage tank.

3. The purification system according to claim 1 or 2, further comprising a switching means for switching between an oil-containing wastewater treatment mode in which the oil-containing wastewater is treated by the membrane filtration device and discharged as the treated water, and a normal operation mode in which water pumped from the water intake source is treated by the membrane filtration device and supplied to the equipment.

4. The facility further comprises a hydroelectric generator; The purification system according to claim 1 or 2, wherein the water pumped up from the water intake source is supplied to the hydroelectric generator as cooling water and / or seal water.

5. The facility further comprises a hydroelectric generator; Supplying water pumped from the water intake source to the hydroelectric generator as cooling water; A circulation path is provided for circulating the cooling water supplied to the hydroelectric generator by returning the cooling water to a stage upstream of the hydroelectric generator after the cooling water is discharged from the hydroelectric generator. The purification system according to claim 1 or 2.

6. A cooling device is provided on the circulation path, The purification system according to claim 5 , wherein heat generated in the cooling device is supplied as heat.

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