JPS61274799A - Apparatus for treating waste water - Google Patents

Abstract

PURPOSE:To efficiently treat waste water, by mounting a treatment tank and a filter means and forming the filter means by parallelly arranging a plurality of filter plates each having a hole provided to the central part thereof to a hollow rotary shaft while providing a gas emitting aeration means between the filter plates. CONSTITUTION:Waste water 14 allowed to fill a treatment tank 10 is contacted with bacteria suspended in said waste water for a predetermined time to be biologically treated. The waste water after treatment is filtered by the semipermeable membrane 30 of a filter plate 24 and the filtrate passes through a membrane support 28, the hollow part 33 of the membrane support 28 and the hollow part 26 of a hollow rotary shaft in this order to be discharged out of the apparatus as treated water 45. The microbes or solid substances adhered to and accumulated on the surface of the semipermeable membrane 30 are washed away when the surface of the membrane passes the position of a gas emitting pipe 40 every one rotation of a filter means 16. By this method, waste water treatment and filtering treatment can be effectively performed in the same tank.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wastewater treatment device, and in particular, wastewater that has been biologically treated by contacting with microorganisms is filtered in the same tank and then removed outside the device. Relates to a device for treating wastewater discharged to □
゛ [Prior Art] ゛“ Methods for biologically treating substances to be removed from wastewater by bringing wastewater into contact with microorganisms are widely used. Typically, there is an activated sludge method. In this method, organic wastewater such as sewage is aerated with microorganisms in an aeration tank, and the organic substances in the wastewater are oxidized and decomposed by the biochemical action of the microorganisms.

Through this aeration treatment, microorganisms rapidly proliferate and are sent to the downstream sinking pond along with the aeration treated wastewater. A portion of the microorganisms precipitated in the sedimentation tank are returned to the aeration tank as return sludge and recycled as microorganisms for non-polluting treatment. The remainder will be treated separately as surplus sludge.

By the way, the activated sludge method described in -1- has two major technical problems. First, it is necessary to perform the non-degradation treatment and the sedimentation treatment separately, which not only complicates the operation but also requires a large amount of land for the sedimentation tank. Sedimentation treatment is a gravity method using a vortex chamber that is allowed to stand still for several hours.

However, depending on the properties of the raw wastewater and operating conditions, bulking may occur and precipitation may not be sufficient. For this reason, it should be discharged - 1; sludge mixes with clear water,
worsen its properties. Furthermore, in many cases, sludge is exposed to anaerobic conditions during the sedimentation process, and a portion of the returned sludge dies. For this reason, non-bubble treatment reduces the activity of microorganisms and causes foaming. Maintaining and managing the sludge concentration (MLSS) in the aeration tank is also difficult, and performance without aeration tends to fluctuate. Second, the MLSS in the aeration tank cannot be maintained high. That is, the MLSS of the aeration tank is equal to the MLSS of the wastewater flowing into the settling basin. By the way, since sludge is fine and has a specific gravity similar to that of water, if the MLSS exceeds a predetermined value of 1-, sedimentation becomes virtually impossible.

Therefore, the MLSS of the aeration tank for operating the activated sludge method within an economical range is 3,000 to 5,000 pp.
m is said to be the limit. If MLSS has such a limit, there will naturally be a limit to the organic matter processing load in non-battery treatment.

In order to solve such problems with the activated sludge method, attempts have been made to omit the settling tank and maintain a high MLSS of the treatment tank to improve treatment efficiency.

For example, Japanese Patent Publication No. 59-11360 discloses a concept of providing a filter at the wastewater outflow [-1] of an aeration tank and omitting the subsequent sedimentation process. However, in such a method, sludge adheres and accumulates on the filter surface, which tends to cause clogging. This causes a decrease in filtration efficiency over time. In addition, the sludge that adheres to and accumulates on the filter and surface does not contribute sufficiently to maintaining the ML and SS of the treatment tank high, and no particular improvement in treatment efficiency can be expected. Recently, efforts have also been made to use a semi-permeable membrane as a filter and use forced turbulence to remove the sludge adhering to the membrane surface, but this requires a large amount of energy to filter through and clean the membrane surface. There was a drawback.

[Problem to be Solved by the Invention 1] The present invention solves the drawbacks of the prior art, and performs biological wastewater treatment using microorganisms and filtration of the treated wastewater in the same tank. In addition, biological wastewater treatment can be performed efficiently by maintaining a high MLSS in the treatment tank, and filtration and cleaning in filtration treatment can be performed easily without consuming much energy. The purpose is to provide wastewater treatment equipment that can

[Means for Solving the Problems] The present invention provides a treatment tank that is equipped with a wastewater inlet and that biologically treats substances to be removed from the wastewater by bringing the wastewater into contact with microorganisms in the tank. , and a filtration means provided in the treatment tank to filter the wastewater and discharge the filtered water to the outside of the treatment tank. The passing means includes a plurality of passing plates each having a hole in the center, which are arranged in parallel to a hollow rotating shaft, and are rotated together by a drive mechanism of the hollow rotating shaft. The water in each pass plate is collected in the hollow part of the hollow rotary shaft and discharged to the outside of the apparatus. In addition, aeration means for discharging gas is provided between each of the passing plates constituting the filtration means.

The microorganisms according to the present invention include not only aerobic microorganisms but also anaerobic microorganisms, and in the case of aerobic treatment, an oxygen-containing gas such as air is used as the gas discharged by the aeration means. on the other hand,. In the case of anaerobic treatment, a gas that does not contain oxygen, such as nitrogen gas, is used. The filter plate preferably has, for example, a membrane support having a water passageway and a support body covered with semi-permeable membranes on both four sides. The aeration means may be one that rotates together with the filtration means, or one that is fixed at a predetermined position within the processing tank separately from the filtration means.

[Function] The filtration means can have a structure in which a large number of thin filtration plates are arranged in parallel at small intervals on a hollow rotating shaft. Therefore, the filtration area per unit volume in the processing tank can be increased. Moreover, since the structure is simple, the volume of the processing tank can be 100% at the desired position within the processing tank.
It can be effectively utilized and placed. Therefore, the overresistance can be significantly reduced, and the filtration function can be sufficiently exerted even with a small pressure difference on the order of hydrostatic pressure based on the water level of the processing tank. ′
, f'' water is quickly discharged out of the device through the hollow part of the hollow rotary shaft. Gas is discharged between each filter plate, and this discharged gas cleans the filtration surface. The surface is always clean and the ',/' superfunction is maintained stably for a long period of time.The discharged gas also serves as a gas source necessary for biological treatment by microorganisms.

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[Embodiment] FIGS. 1 to 5 are explanatory diagrams showing a first embodiment of the present invention. A wastewater inflow pipe 12 is provided on one side of the treatment tank IO, and is filled with organic wastewater 14. code 1
Reference numeral 6 denotes a passing means, in which a hollow rotating shaft 18 is supported by bearings 20, 22 provided on the side plate of the processing tank IO, and is rotatable at a constant speed by a drive mechanism (not shown). A plurality of pass plates 24 are provided in parallel at regular intervals on the hollow rotating shaft 18.

The detailed structure of the filter plate 24 is shown in FIG. The disc-shaped filter plate 24 is composed of a hollow membrane support 28 and a semipermeable membrane 30 covering both outer surfaces of the membrane support 28, and has a 632 in the center of the disc. The hollow rotating shaft 18 is provided through this hole 32, and the hollow portion 3 of the membrane support 28
3 and the hollow portion 26 of the hollow rotating shaft 18 are in communication with each other. The outer periphery of the filter plate 24 is sealed by a seal member 34, and the connection portion between the filter plate 24 and the hollow rotating shaft 18 is sealed by a seal member 36.

Reference numeral 38 denotes an aeration means, which is provided with gas discharge pipes 40 in each gap where the filter passage plates 4 are arranged in parallel, and these gas discharge pipes 40 are connected to a gas introduction pipe 42. The gas discharge pipe 40 is a thin tube provided with a large number of gas discharge ports 44,
The discharge direction (arrow A) is determined by the passage plate 2 as shown in FIG.
4 is opposite to the direction of rotation (arrow B) and in a direction that hits the surface of the semipermeable membrane 30 of the filter plate 24 through which the discharge flow passes, i. ing.

In the configuration described in -1-, the wastewater 14 filled in the treatment tank 10 is biologically treated by contacting for a predetermined period of time with microorganisms suspended in the wastewater.

The wastewater that has undergone this treatment is filtered by the semipermeable membrane 30 of the filter plate 24, and the clarified water is filtered through the membrane support 28, the hollow part 33 of the membrane support, and the hollow part 2.6 of the hollow rotating shaft. The treated water 45 is discharged to the outside of the apparatus through the following steps.

Microorganisms and solid substances floating in the wastewater temporarily adhere to and accumulate on the membrane surface of the semipermeable membrane 30 as the wastewater passes through. However, these sludges are separated from the membrane surface by the gas discharged from the gas discharge pipe 40 and the stirring action of the waste water caused by the gas discharge.

That is, each membrane surface passes through the position of the gas discharge pipe 40 every time the E-filtering means 16 rotates once, so that the surfaces are cleaned in a very short cycle. For this reason, the membrane surface is always kept clean and the filter function continues stably for a long period of time. The sludge separated from the membrane surface becomes suspended in the wastewater again, and the MLSS in the treatment tank IO can be maintained at a high level of, for example, about 5,000 to 10,000 ppm. Therefore, the treatment performance is improved several times compared to the conventional activated sludge method. Therefore, the capacity of the processing tank IO can be reduced accordingly. Moreover, like the conventional activated sludge method, MLSS can also be operated as a 3,000-5,000 pp garden. The discharge gas used in the washing frame of the membrane surface of the filtration device 18 is also used as an air source when the treatment device performs biological aerobic treatment, and as a gas for maintaining anaerobic conditions when the treatment device performs anaerobic treatment. used as a source. As shown in FIG. 4, mutual contact between wastewater, sludge, and gas is effectively achieved by stirring by gas discharge, rising of bubbles, and rotation of the filter plate 24. By continuously performing the above treatment, the MLSS in the treatment tank 10 gradually increases due to the growth of microorganisms, and the source of nutrients (i.e., organic substances to be treated) in the raw wastewater becomes insufficient, and the MLSS in the treatment tank 10 gradually increases due to the growth of microorganisms. There may be a situation where the activity decreases reciprocally. For this purpose, a sludge settling section 48 is provided in the lower part of the treatment tank 10, and excess sludge is drawn out from the sludge discharge pipe 50 continuously or intermittently.

The Er overdriving force of the filtration means is the pressure difference between the wastewater and the filtrate, and hydrostatic pressure is a convenient means for obtaining this pressure difference. In order to utilize hydrostatic pressure as much as possible, it is preferable that the filtration means be installed at the lower part of the treatment tank IO. In addition to the hydrostatic pressure, the pressure difference may be increased by increasing the pressure on the waste water side or reducing the pressure on the waste water side.

The membrane support used for the filtration plate is a porous material such as sintered metal, ceramics, or porous plastic, or a porous plate with an uneven surface and a passage for water.

The hollow portion 33 described above is not particularly necessary as long as this membrane support has a passageway for water. It may also be used as an E filter plate. Further, the recessed portion of the filter plate is not limited to a semipermeable membrane, and other membranes having fine pores, such as a coating film, may be used. The microorganisms suspended in the treatment tank 10 are selected depending on the substances to be removed from the wastewater. As a means of suspending microorganisms, just like the conventional activated sludge method, you can simply float them without using any special method! In addition to the above-mentioned method, microorganisms may be suspended on a fine inorganic carrier, or immobilized microorganisms in which microorganisms are encircled and immobilized within a polymer gel may be made to flow. In particular, when immobilized microorganisms are used, M T and S S can always be maintained stably and high, and the amount of sludge floating alone in wastewater is 1/100 to 1/1000 compared to the activated sludge method. can be reduced to For this reason, it is effective in significantly reducing the amount of suspended solids in the filtration process.

FIG. 5 shows a modification of the gas discharge pipe. FIG. 5(A) shows a state where a baffle plate 52 is attached to the rear side of the gas discharge pipe 40A.
In FIG. 5(b), the cross-sectional shape of the gas discharge pipe 40B is triangular. In either case, the physical action of the shape of the gas discharge pipe promotes the stirring and collision effects of the liquid and gas near the membrane surface, making cleaning of the membrane surface even more effective.

FIG. 6 shows a second embodiment of the present invention. In this embodiment, two sets of passing means 56 each having a hollow rotating shaft 54 are provided, and one of the passing plates 58 of the r passing means is , the other ″,
t'' is inserted between the passing plates of the passing means, so that the passing plates of each passing means are arranged alternately.

By reversing the rotation direction of each passing means, stirring of the liquid on the filtration passing surface is accelerated, and concentration polarization on the filtration surface can be suppressed.

Furthermore, the hollow rotary shaft 54 has a double structure, and of the double tubes, the outer tube 60 serves as a passage for filtered water, and the inner tube 62 serves as a passage for aeration gas. The inner tubes 62 are arranged in parallel;
It communicates with a gas discharge hole 64 opened between the r passage plates 58, and discharges the gas from the gas introduction pipe 66 to the wastewater side. Note that 66 is a drive mechanism for the hollow rotating shaft, and 68 and 70 are rotary joints that connect the conduit and the hollow rotating shaft.

According to this embodiment, the area of the recessed part of the E filtration means can be increased, and the recessed part of the E filtration means can be cleaned more effectively by mutual rotation of each of the E filtration means.

In addition, since the passage for the aeration phase gas is integrated into the hollow rotating shaft, the structure of the device is simple.
Maintenance of the f″ ventilation means and the aeration means becomes easier.
□ In each of the above embodiments, the shape of the pass plate constituting the pass means is described as being disc-shaped, but it is not limited to the disc shape, but may be rectangular or polygonal. In the explanation above, a hollow rotating shaft is installed horizontally, and a filter plate is attached vertically to the hollow rotating shaft. It may also be configured horizontally. Further, the hollow plate does not need to be attached perpendicularly to the hollow rotating shaft, and may be attached at an angle. If it is tilted, the agitation of the liquid due to the rotation of the filter plate will become more intense, and it can be expected that the cleaning effect of the filter plate will be improved. Further, the ',/'' overplates are not limited to pure planar ones, and may have cap-shaped or partially spherical outer surfaces.

[Effects of the Invention] According to the present invention, biological wastewater treatment using microorganisms,
The filtration treatment of the treated wastewater can be effectively carried out in the same layer. Therefore, it is possible to maintain a high MLSS in the treatment layer and perform biological wastewater treatment efficiently and stably over a long period of time. In addition, the overdriving force required for overtreatment is only required to add hydrostatic pressure or a slight amount of forced pressurization or depressurization to the hydrostatic pressure.
Less energy is required for overtreatment.

[Brief explanation of the drawing]

1 to 5 are drawings for explaining a first embodiment of the present invention, in which FIG. 1 is a side sectional view showing an outline of the device, and FIG.
The figure is a partial cross-sectional view showing the detailed configuration of the majority of stages, Figure 3 is an explanatory view showing the cross-sectional shape of the gas discharge pipe, Figure 4 is a front cross-sectional view,
FIG. 5 is an explanatory diagram showing a modification of the cross-sectional shape of the gas discharge pipe;
FIG. 6 is a side sectional view showing an outline of a device according to a second embodiment of the present invention. 10・φ・Processing tank, 12・Fist・Wastewater inflow pipe, 1611・Fist filter means, 18・Hollow rotating shaft, 2411・・filtration plate, 28・・membrane support, 30・・- Semipermeable membrane, 32...hole, 38...aeration means, 40...gas discharge pipe. Agent Patent Attorney Atsushi Nakajima 1 Figure 4077゛人σ Earth Buddha W It) Figure 2 Figure 3 Figure 4 Figure 5 ← 0 (B) Figure 6

Claims (4)

[Claims] (1) A treatment tank that is equipped with a wastewater inlet and that biologically treats substances to be removed from the wastewater by bringing the wastewater and microorganisms into contact within the tank, and a treatment tank that is installed within this treatment tank and that filters the wastewater. , a wastewater treatment device comprising a filtration means for discharging filtrate to the outside of the treatment tank, the filtration means having a plurality of filter plates each having a hole in the center, and a hollow rotating shaft serving as an outlet for the filtrate; are arranged in parallel at regular intervals through the holes, and are rotated together by a drive mechanism of the hollow rotating shaft, and an aeration means for discharging gas is provided between each filter plate constituting the filter means. A wastewater treatment device characterized by: (2) The wastewater treatment device according to claim 1, wherein the filter plate is a membrane support having a filtrate passage and semipermeable membranes covered on both sides. (3) The aeration means is a gas discharge pipe fixedly provided between each of the filter plates, and discharges gas in an oblique direction opposite to the rotational direction of the filter plates. The wastewater treatment device according to item 1. (4) The aeration means is provided integrally with the hollow rotating shaft, and discharges gas from the center of the sieve plate toward the outer periphery. Wastewater treatment equipment.