JP2008000705A - Sewage treatment apparatus of satellite treatment plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save a space of a sewage treatment apparatus in a satellite treatment plant. <P>SOLUTION: The sewage treatment apparatus 10 of the satellite treatment plant comprises a water-intake means 12 for taking water to be treated of the surface layer of sludge matter-containing sewage flowing through a sewer main line 18, a high-rate filter means 14 for performing solid-liquid separation with a filter medium layer 24 formed in a treatment tank 20, into which the water to be treated taken by the water-intake means 12 flows upward, by filling with a filter medium having a lower specific gravity than that of the water to be treated, and a membrane separation activated sludge means 16 for introducing the outflow water of the high-rate filter means 14 into an anaerobic tank 30 to anaerobically treat it, then introducing the outflow water from the anaerobic tank 30 into an aerobic tank 32 to aerobically treat it, and at the same time performing solid-liquid separation by a membrane separation part 36 installed in the aerobic tank 32. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention particularly relates to a sewage treatment apparatus for a satellite treatment plant that collects part of sewage from a sewage main line upstream of a sewage main line, performs sewage treatment, and supplies reused water of the sewage to an urban area upstream of the sewer.

  FIG. 6 is an explanatory diagram of a satellite treatment plant. As shown in the figure, the sewer is connected to a sewer main line 1 for sending sewage from the upstream side to the downstream side, a plurality of branch pipes 2 branched and connected to the upstream side of the sewer main line 1, and a downstream end of the sewer main line 1. And a final treatment plant 3. The sewer collects sewage flowing from a plurality of branch pipes 2 on the upstream side by a sewage main line 1 and processes the sewage at a terminal treatment plant 3 at the downstream end to generate reused water for the sewage. Recycled water is mainly used for industrial treated water, miscellaneous water, biotope, river water, fire prevention water, emergency life water, etc. Such recycled water is difficult to send from the downstream treatment plant to the upstream urban area, and is often used in the vicinity of the final treatment plant. In recent years, a satellite treatment plant 4 is provided in a satellite manner in an urban area upstream of a sewer main line to perform sewage treatment of the sewer so that reused water can be used also in an urban area near the treatment plant. This makes it possible to effectively use the reused water that has been widely used in the vicinity of the sewage treatment plant in the urban area upstream of the sewer.

Here, the treatment process of a general terminal sewage treatment plant will be described. The terminal sewage treatment plant is a solid-liquid separation facility using gravity sedimentation by the sand basin and the first sedimentation basin. As shown in FIG. 7, the sewage flowing from the sewer main line to the treatment plant is first introduced into the sand basin 5. In the sand settling basin 5, the flow rate is slowed down so that large dust or sand contained in the sewage is settled and separated from the sewage. The separated sewage is introduced into the adjacent first settling basin 6 by a pump. In the first settling basin 6, small dust that has not settled in the settling basin 5 is settled at a slower speed than the settling basin 5 and separated from the sewage. Then, after the activated sludge reaction of sewage is performed in the biological reaction tank 7, solid-liquid separation using gravity sedimentation is performed in the final sedimentation tank 8. Then, after sterilization by the disinfection facility 9, it is discharged into rivers and sea areas. (A conventional membrane separation activated sludge apparatus is disclosed in, for example, Patent Documents 1 and 2.)
Japanese Patent No. 3257944 Japanese Patent No. 3257946

  The satellite treatment plant is preferably a space-saving installation type because it is placed in an urban area where it is difficult to secure a large installation space, and the biological reaction time can be shortened by maintaining the activated sludge concentration at a high concentration, and The membrane separation activated sludge method, which can omit the final sedimentation basin and disinfection facility by installing a membrane separation device in the biological reaction tank and performing solid-liquid separation, can be said to be suitable for a satellite treatment plant.

  On the other hand, it is known that activated sludge tends to have different sludge viscosities depending on the raw water supply. Compared with the case where the inflow water and the outflow water of the first settling basin are supplied, the activated sludge suspended matter in the tank Concentration: When MLSS (Mixed Liquid Suspended Solid) exceeds 12 g / l, it is known that the viscosity increases when the inflow water of the first settling basin is supplied. The increase in viscosity is said to be caused by an increase in the amount of glycoprotein derived from microbial metabolites, but the mechanism of the increase is not clear. However, when the viscosity increases, the filterability of activated sludge decreases and the frequency of chemical cleaning with chemicals increases. Therefore, considering maintenance, the feed water to the membrane-separated activated sludge method is the effluent from the first sedimentation basin. It is desirable that the water quality is equivalent or similar to

  By the way, since the first sedimentation basin is a solid-liquid separation facility using gravity sedimentation, for example, the solid-liquid separation speed in the combined sewer is limited to 50 m / day at the maximum, and a large site area is required. As a method to reduce the site area, first add organic polymer flocculant or inorganic flocculant into the inflow water of the sedimentation basin to combine the particles to form particles with high precipitation speed, solid-liquid separation speed Although a method for speeding up the process can be considered, it is necessary to consider an increase in maintenance cost due to the use of chemicals.

  SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and is intended to save space in a sewage treatment apparatus at a satellite treatment plant.

  A sewage treatment apparatus for a satellite treatment plant according to the present invention is provided with a satellite treatment plant branched on the upstream side of a sewer main line, and a sewage treatment means by membrane separation of treated water that has taken a part of the surface layer of the sewage main line sewage. And the treated water of the sewage treatment means is supplied to a nearby urban area.

  In this case, the sewage treatment means is directly connected to a high-speed filtration means for performing solid-liquid separation by pressurizing and flowing the treated water into a filter medium layer formed in a treatment tank, and a discharge port of the high-speed filtration means. The effluent water from the high-speed filtration means is introduced into an anaerobic tank for anaerobic treatment, and the effluent water from the anaerobic tank is introduced into an aerobic tank for aerobic treatment, and is provided inside the aerobic tank. And a membrane separation activated sludge means for performing solid-liquid separation in the membrane separation unit.

  In this case, a suction port provided with a float is attached to a pipe between the introduction side and the sewer main line on the introduction side of the water to be treated of the high-speed filtration means, so that the surface layer of the sewage flowing through the sewer main line is covered. It is good to have a water intake means for taking treated water. The membrane separation activated sludge means may be provided with a reverse osmosis membrane or a nanofiltration membrane on the treated water discharge side. Moreover, the said membrane separation activated sludge means is good to have added activated carbon in the processing tank.

  In the present invention as described above, a satellite treatment plant is provided on the upstream side of the sewer main line, and the treated water that has taken a part of the surface layer of the sewage main line is directly connected to the high-speed filtration means and the membrane separation activated sludge means. Sewage treatment is performed in combination. For this reason, it is possible to significantly reduce the site area of the satellite treatment plant by adopting high-speed filtration equipment as an alternative to the first settling basin that has been conventionally used. Therefore, a satellite treatment plant can be installed even in a small installation space in an urban area. In addition, the high-speed filtration means can reduce the installation area and supply the effluent water from the high-speed filtration means to the membrane separation activated sludge means in the subsequent stage to suppress the increase in sludge viscosity. The operation of the means becomes possible, and the treatment cost of sewage treatment can be reduced.

  The means for taking water to be treated of the present invention takes a part of the surface layer of sewage. For this reason, the intake of the sludge substance contained in sewage can be reduced, and the burden of the purification process of a sewage treatment apparatus can be reduced.

  A reverse osmosis membrane or a nanofiltration membrane is attached to the subsequent stage of the membrane separation activated sludge means of the present invention. The reverse osmosis membrane can remove inorganic molecules contained in water, and a cleanness close to that of drinking water can be obtained. In addition, the nanofiltration membrane removes the chromaticity component of the water to be treated to obtain transparent treated water. Therefore, by selecting a reverse osmosis membrane or a nanofiltration membrane arbitrarily, reused water can be obtained according to the application.

  Activated carbon is added to the membrane separation activated sludge means of the present invention. For this reason, effects such as deodorization of water to be treated, water purification, adsorption and the like are obtained along with the activated sludge reaction. Moreover, activated carbon and treated water can be easily separated by the membrane separation unit.

  An embodiment of a sewage treatment apparatus for a satellite treatment plant according to the present invention will be described in detail below with reference to the accompanying drawings. Drawing 1 is a figure showing the composition outline of the sewage treatment equipment of the satellite treatment plant concerning an embodiment. FIG. 2 is an explanatory diagram of the sewage treatment apparatus of the satellite treatment plant according to the embodiment.

  The satellite treatment plant where the sewage treatment apparatus 10 of the satellite treatment plant is installed is installed in a plurality of urban areas on the upstream side of the sewer main line 18. In addition, the satellite treatment plant is formed between the sewer main line 18 and the city area and takes a part of the sewage from the sewer main line 18. As shown in the figure, a sewage treatment apparatus 10 installed in a satellite treatment plant has a basic configuration of water intake means 12 for water to be treated, high-speed filtration means 14 serving as sewage treatment means, and membrane separation activated sludge means 16.

  The sewage treatment apparatus 10 introduces sewage taken from the sewer main line 18 as shown in FIG. The water intake means 12 has a configuration in which a pump 15 is attached in the middle of a pipe 13 connecting between the sewer main line 18 and the inlet of the high-speed filtration means 14, and a hose 13 a is provided at the end of the pipe 13. The suction port 17 of the hose 13a on the sewer main line 18 side is floated on the sewage containing pollutants flowing through the sewer main line 18 via a floating body such as a float 19 and attached near the surface layer. And the surface water is taken in by suction of the pump 15 from the suction port 17 at the pipe end while the pipe end floats on the sewage.

  The high speed filtration means 14 includes a sewage introduction port 22 below the processing tank 20. Further, a filter medium layer 24 is formed in the horizontal direction above the inside of the treatment tank 20, and a treated water discharge port 26 is attached to the upper end portion. The filter medium layer 24 flows out to the outside by protecting a filter medium having a specific gravity smaller than that of the water to be treated, for example, a filter medium having a specific gravity of 1 or less and having no water absorption with a screen having a smaller opening than the filter medium. Is preventing. A drawing tube 21 is attached below the treatment tank 20 so that sludge or washing wastewater deposited below the treatment tank 20 is discharged to the outside. The washing waste water may be connected downstream of the water intake means 12 attached to the sewer main line 18 and returned to the sewer.

  The membrane separation activated sludge means 16 includes an anaerobic tank 30 and an aerobic tank 32. The anaerobic tank 30 and the aerobic tank 32 are arranged adjacent to each other via a plurality of partition plates 33. The anaerobic tank 30 and the aerobic tank 32 are provided with a circulation path 34 to circulate activated sludge. The introduction port of the anaerobic tank 30 is directly connected to the discharge port 26 of the high-speed filtration means 14 via the pipe 23. The water to be treated from the high speed filtration means 14 is introduced into the anaerobic tank 30. In the anaerobic tank 30, the water to be treated is treated with activated sludge.

  The aerobic tank 32 introduces activated sludge treated water from the anaerobic tank 30 for aerobic treatment, and performs solid-liquid separation by a membrane separation unit 36 provided in the tank. The membrane separation unit 36 arranges a plurality of filtration membranes in the casing in parallel, and discharges the membrane permeated water (treated water) from the piping 37 connected to the upper portion of the casing to the outside by a suction pump or gravity filtration using a water head difference. I am doing so. An aeration means 38 is attached to the aerobic tank 32 below the membrane separation unit 36. The air diffuser 38 is spaced from the bottom surface of the aerobic tank 32 at a predetermined position.

  A surplus sludge extraction pipe 40 is formed below the aerobic tank 32 so that the excess sludge in the aerobic tank 32 is discharged to the outside. Similarly to the above, this excess sludge can be connected to the downstream side of the water intake means 12 attached to the sewer main line 18 and returned to the sewer.

  The sewage treatment apparatus 10 in the satellite treatment plant having the above-described configuration operates as follows. A plurality of satellite treatment plants are provided on the upstream side of the sewer main line 18 and in an urban area where there is a demand for sewer reprocessing water. In the satellite treatment plant, the water intake means 12 for the treated water is connected to the sewer main line 18. The water intake means 12 of the treated water floats the suction port 17 of the pipe 13 on the sewage flowing through the sewer main line 18 via the float 19, and the surface layer of the sewage containing pollutants by suction of a pump provided in the middle of the pipe. Take only treated water. The amount of drainage of the sewer main line 18 varies depending on the amount of rainfall. Therefore, by providing the float 19 at the pipe end on the sewer main line side, the water to be treated in the surface layer portion of the sewage can be taken without sucking the sludge accumulated on the bottom surface of the sewer. Thereby, the intake of the sludge substance contained in the sewage of a sewer main line can be reduced, and the burden of the purification process of the sewage treatment apparatus 10 can be reduced.

  The water to be treated which has taken a part of the sewage from the sewer main line 18 by the water intake means 12 is introduced into the treatment tank 20 from the introduction port 22 of the high speed filtration means 14 through the pipe 13. The water to be treated introduced into the treatment tank 20 flows toward the discharge port 26 formed above the treatment tank 20. When the water to be treated passes between the filter media of the filter media layer 24, a large sludge substance in the water to be treated is removed. The treated water that has passed through the high-speed filtration means 14 maintains the same level of cleanness as the treated water that has passed through the conventional first sedimentation basin. Moreover, the high-speed filtration means 14 can reduce installation space significantly compared with the treatment plant provided with the conventional sedimentation basin and the first sedimentation basin.

  The sewage treatment apparatus 10 of the present invention has a configuration in which the high-speed filtration means 14 and the membrane separation activated sludge means 16 are directly connected and combined, and the treated water that has passed through the high-speed filtration means 14 is membrane-separated directly from the discharge port 26. It is introduced into the inlet of the activated sludge means 16. The treated water introduced into the anaerobic tank 30 of the membrane separation activated sludge means 16 undergoes a biological reaction with the activated sludge adjusted to a predetermined concentration. Then, the activated sludge treated water is introduced into the adjacent aerobic tank 32 and sucked from the membrane separation unit 36 provided inside the treatment tank. The membrane separation membrane 36 has a plurality of filtration membranes arranged in parallel, and the treated water and activated sludge are separated by the filtration membrane, and the treated water that has passed through the filtration membrane is discharged to the outside as reused water. The high-speed filtration means and the membrane separation activated sludge means are integrated, and the processing tank of the high-speed filtration means, the anaerobic tank of the membrane separation activated sludge means, and the aerobic tank are arranged side by side to save space. Also good.

  FIG. 3 is an explanatory diagram of a first modification of the sewage treatment apparatus according to the embodiment. As shown in the figure, in the first modification of the sewage treatment apparatus, a reverse osmosis membrane (RO membrane) or a nanofiltration membrane (NF membrane) is attached to the treated water outflow path by the membrane separation activated sludge means 16. The reverse osmosis membrane (RO membrane) can remove inorganic molecules contained in the water by allowing the water to be treated to pass through, and a cleanliness level close to that of drinking water can be obtained. Moreover, the nanofiltration membrane (NF membrane) can remove the chromaticity component contained in to-be-processed water by letting treated water pass, and can set it as transparent treated water. As described above, the treated water treated by the membrane separation activated sludge means 16 can select reused osmosis membrane or nanofiltration membrane to obtain reused water according to the intended use.

  FIG. 4 is an explanatory diagram of a second modification of the sewage treatment apparatus according to the embodiment. As shown in the figure, in the second modification of the sewage treatment apparatus, activated carbon 42 is added to the anaerobic tank 30 and the aerobic tank 32 of the membrane separation activated sludge means 16. The activated carbon 42 is porous and adsorbable, and effects such as deodorization, water purification and adsorption are known. As a result, the water to be treated can be decolored together with the activated sludge treatment reaction by the membrane separation activated sludge means 16. The added activated carbon 42 can be easily separated from the treated water by the membrane separation unit 36.

  FIG. 5 is a view showing a modification of the water intake means according to the embodiment. As shown in FIG. 1 (1), the end of the pipe 13 is attached in a direction perpendicular to the sewage flow of the sewer main line 18 at a predetermined interval from the bottom, and a plurality of openings 13b are provided on the side of the pipe 13. They are formed side by side. Then, an outer cylinder 44 having a diameter larger than that of the pipe 13 is attached to the end of the pipe 13. Since the outer cylinder 44 is made of a material having a specific gravity smaller than 1, the outer cylinder 44 floats on the sewage and can take sewage from the opening 13 b exposed from the lower end of the outer cylinder 44. As shown in FIG. 2B, the movable pipe 46 is attached to the end of the pipe 13 via a joint that can rotate in the direction indicated by the arrow a. The movable pipe 46 is made of a material having a specific gravity smaller than 1, or the float 19 is attached to the opening, so that the movable pipe 46 can easily float on the sewage and take up the surface water of the sewage.

  As described above, according to the sewage treatment apparatus of such a satellite treatment plant, a high-speed filtration facility is adopted as an alternative to the first sedimentation basin for the stable operation of the membrane separation activated sludge facility in the satellite treatment plant, and the high-speed filtration is performed. By combining the means and membrane separation activated sludge means, the site area of the satellite treatment plant can be greatly reduced. According to the present invention, for example, when the solid-liquid separation speed of the high-speed filtration means is 400 m / day, the required area is 1/8 or less of that in the case of a treatment plant employing a conventional first sedimentation basin. In addition, by supplying the effluent from the high-speed filtration means to the membrane separation activated sludge means, it is possible to operate the membrane separation activated sludge apparatus stably because the increase in sludge viscosity is suppressed, and it is possible to reduce the treatment cost of the sewage. It becomes.

It is a figure which shows the structure outline of the sewage treatment apparatus of a satellite treatment plant. It is explanatory drawing of the sewage treatment apparatus of a satellite treatment plant. It is explanatory drawing of the 1st modification of a sewage treatment apparatus. It is explanatory drawing of the 2nd modification of a sewage treatment apparatus. It is explanatory drawing of the modification of the water intake means which concerns on embodiment. It is explanatory drawing of a satellite treatment plant. It is explanatory drawing of the treatment process of the conventional treatment plant.

Explanation of symbols

1 ......... Sewer main line, 2 ......... Branch pipe, 3 ......... Sewage treatment plant, 4 ...... Satellite treatment plant, 5 ...... Sedimentation basin, 6 ......... First sedimentation basin, 7 ... Reaction tank, 8 ......... Final sedimentation basin, 9 ......... Disinfection equipment, 10 ......... Sewage treatment equipment, 12 ......... Water intake means, 13 ......... Piping, 14 ...... High-speed filtration means, 15 ... ... Pump, 16 ......... Membrane separation activated sludge means, 17 ......... Suction port, 18 ......... Sewer main line, 19 ......... Float, 20 ...... Treatment tank, 21 ...... Drawer, 22 ... ... Introduction port, 23 ...... Piping, 24 ......... Filter medium layer, 26 ......... Discharge port, 30 ...... Anaerobic tank, 32 ...... Aerobic tank, 33 ......... Partition plate, 34 ......... Circulation path, 36 ......... Membrane separation part, 37 ......... Piping, 38 ......... Aeration means, 40 ...... Drawing pipe, 42 ......... Activated carbon, 44 ...... Outer cylinder, 46 ...... moveable pipe.

Claims (5)

  A satellite treatment plant branching upstream of the sewer main line is provided, and includes a sewage treatment means by membrane separation of treated water that has taken a part of the surface layer of the sewage main line, and the treated water of the sewage treatment means is disposed in the vicinity. A sewage treatment apparatus for a satellite treatment plant, characterized by being supplied to an urban area. The sewage treatment means includes
High-speed filtration means for performing solid-liquid separation by pressurizing and flowing the water to be treated into a filter medium layer formed in a treatment tank;
Directly connected to the discharge port of the high-speed filtration means, introduces effluent water from the high-speed filtration means into an anaerobic tank and anaerobically treats it, and introduces effluent water from the anaerobic tank into an aerobic tank for aerobic treatment. A membrane separation activated sludge means for performing solid-liquid separation in a membrane separation section provided in the aerobic tank;
The sewage treatment apparatus for a satellite treatment plant according to claim 1, wherein   A suction port having a float is attached to a pipe between the introduction side and the sewer main line on the introduction side of the treated water of the high-speed filtration means, and the treated water of the surface layer of sewage flowing through the sewer main line is taken. The sewage treatment apparatus for a satellite treatment plant according to claim 2, further comprising water intake means for carrying out the process.   The sewage treatment apparatus for a satellite treatment plant according to claim 2 or 3, wherein the membrane separation activated sludge means has a reverse osmosis membrane or a nanofiltration membrane attached to the treated water discharge side.   The sludge treatment apparatus for a satellite treatment plant according to any one of claims 2 to 4, wherein the membrane separation activated sludge means has activated carbon added to a treatment tank.

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