JPH04305288A - Water treating equipment - Google Patents

Abstract

PURPOSE:To allow the return of the clean treated water permeated through the external pressure type ceramic filter of a precision filter device to water intake equipment through a reflux route for back washing water by capturing the turbid matter of the solid contents contained in the back washing water by the external pressure type ceramic filter. CONSTITUTION:Raw water is taken in from a water source and is passed through a water purifying stage of chemical mixing, flocculating and settling, filtering, etc., by which the raw water is purified. The treated water subjected to the purification is stored in a clean water reservoir. The external pressure type ceramic filter 24 immersed in a treating tank 22 is provided in order to treat the waste water generated in the mid-way of the stage. An air diffuser 27 is disposed in the lower part of this filter 24 and a suction pump 26 communicated on the suction side with the filter 24 is provided on the outside of the treating tank 22. Consequently, the clean treated water permeated through the filter 24 is returned through the reflux route for washing water to the water intake equipment and the action of the turbid matter contained in the back washing water again as load in the mixing, flocculating, settling and filtering equipment is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to water treatment equipment that takes raw water from rivers and the like and purifies it into sanitary water.

0002

2. Description of the Related Art Conventional water treatment equipment is, for example, as shown in FIG. In Figure 4, raw water pumped up from the water intake 1 is supplied to the landing well 3 through the dust remover 2, and at the landing well 3, sodium hypochlorite for disinfection is supplied from the sodium hypochlorite storage tank 4 as needed. be done. Further, an alkali agent, a flocculant, and a flocculating aid supplied from the caustic soda storage tank 6 and the flocculant storage tank 7 are mixed with the raw water sent from the landing well 3 to the mixing pond 5.

[0003]Then, the raw water mixed with the flocculant, flocculation aid and alkaline agent in the mixing pond 5 is transferred to the flocculation pond 8.
The particles of suspended solids that are difficult to settle by gravity in the raw water are aggregated and formed into flocs. Further, the raw water containing flocs is sent to a chemical settling tank 9 where the flocs are precipitated and removed, and the supernatant water is sent to a secondary mixing tank 10. Further, in the secondary mixing pond 10, an alkaline agent and a flocculant/flocculation aid supplied from the caustic soda storage tank 6 and the flocculant storage tank 7 are mixed.

[0004] Then, the chemical settling tank 9 or the secondary mixing tank 1
The supernatant water sent from 0 to the rapid filtration basin 11 has suspended solids captured by the filtration action of the filter medium, and the treated water that has passed through the filter medium is treated with hypochlorous acid for disinfection, which is supplied from the sodium hypochlorite storage tank 4. After adding soda, it is sent to the water purification pond 12. Furthermore, the treated water is sent to an advanced treatment facility consisting of an ozone contact tank 13 and an activated carbon filtration basin 14, as necessary, to remove trace organic matter, organic chlorine compounds, ammonia nitrogen, odor components, and the like.

[0005] The suspended solids removed in the rapid filtration basin 11 and the activated carbon filtration basin 14 are washed out by backwash water,
Backwash water containing turbidity is returned to the landing well 3 via the drainage pond 15. Further, the sludge settled in the chemical settling tank 9 is sent to the thickening tank 17 via the sludge tank 16, and the supernatant water in the thickening tank 17 is sent to the drainage tank 15.

[0006]

However, in the conventional configuration described above, at least one of the backwash water of the rapid filtration basin 11, the backwash water of the activated carbon filtration basin 14, and the separated liquid of the concentration tank 17 is discharged from the drainage basin 15. The suspended solids captured in the rapid filtration basin 11 and the activated carbon filtration basin 14 as well as the suspended solids leaked from the thickening tank 17 are returned to the landing well 3 through the filtration basin 8 and the chemical settling basin 9 as a load. There was a problem at play.

[0007] The present invention solves the above-mentioned problems, and an object thereof is to provide water treatment equipment that can return backwash water from a rapid filtration basin or the like to a receiving well with its turbidity removed.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the water treatment equipment of the present invention takes raw water from a water source, purifies the raw water through water purification processes such as chemical mixing, coagulation sedimentation, and filtration. In the process of storing treated water in a water purification pond, an external pressure type ceramic filter is immersed in a treatment tank provided to treat wastewater generated during the process, and a filter installed at the bottom of this external pressure type ceramic filter is used. The system is equipped with an air diffuser and a suction pump provided outside the processing tank and whose suction side communicates with an external pressure type ceramic filter.

[0009]

[Function] With the above configuration, the backwash water in the treatment tank is sucked through the external pressure ceramic filter using the suction pump, and the solids contained in the backwash water are removed by precision filtration using the external pressure ceramic filter. The liquid that is captured and remains in the treatment tank and passes through the external pressure type ceramic filter becomes clear treated water that is extracted outside the treatment tank and returned to the water intake equipment through a reflux route such as backwash water. . Therefore, the suspended solids contained in backwash water, etc. do not flow back to the water intake equipment, and are prevented from acting as a load on the mixing/coagulation equipment, sedimentation tank, and filtration equipment again.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Note that members that perform the same functions as those in the configuration shown in FIG. 4 are given the same numbers, and description thereof will be omitted. In FIGS. 1 to 3, the precision filtration device 21 is installed in a recirculation path for backwash water discharged from the rapid filtration basin 11 or in the drainage basin 15. Then, the precision filtration device 21
5, and an external pressure type ceramic filter 24 which is placed immersed in backwash water 23 etc. stored inside the processing tank 22, and the external pressure type ceramic filter 24 has a cylindrical shape. It consists of a plurality of external pressure type ceramic tubes 25 formed, and the inside of the ceramic tube 25 communicates with the suction side of a suction pump 26 provided outside the processing tank 22. Further, the discharge side of the suction pump 26 communicates with water intake equipment, for example, the water landing well 3 .

[0011] Then, an external pressure type ceramic filter 24
An air diffuser 27 is provided below the processing tank 22.
It communicates with the discharge side of the Further, the bottom of the treatment tank 22 communicates with the suction side of the sludge drawing pump 29.

[0012] The operation of the above configuration will be explained below. From the rapid filtration basin 11 and the activated carbon filtration basin 14 to the treatment tank 2
The backwash water 23 supplied to the backwash water 2 passes through the external pressure type ceramic filter 24 and is sucked by the suction pump 26, and is purified by the external pressure type ceramic filter 24 through precision filtration.
The suspended matter consisting of the solids contained in 3 is captured. Also,
The air lift action of the air 30 diffused from the aeration device 27 generates an upward stirring flow A, and the shearing force of the upward stirring flow A removes the gel layer adhering to the surface of each ceramic tube 25 of the external pressure type ceramic filter 24. Ru. The liquid that has passed through the external pressure type ceramic filter 24 is extracted as clear treated water 31, and is returned to the receiving well 3 and the like via the drainage pond 15. Further, the captured suspended matter is discharged to the outside of the treatment tank 22 by the sludge suction pump 29. Therefore, the suspended solids contained in the backwash water 23 do not flow back to the landing well 3, and act as a load again in the mixing pond 5, floc formation pond 8, chemical settling pond 9, secondary mixing pond 10, and rapid filtration pond 11. This will be prevented.

Naturally, the drainage pond and the treatment tank may be integrated, and it goes without saying that there is no functional difference even if separate tanks are connected by a pipe.

[0014]

Effects of the Invention As described above, according to the present invention, the solid turbidity contained in the backwash water is captured by the external pressure type ceramic filter of the precision filtration device, thereby reducing the clarification that has passed through the external pressure type ceramic filter. The treated water can be returned to the intake equipment through the backwash water reflux route, and the turbidity contained in the backwash water can be prevented from acting as a load on the mixing/coagulation equipment, sedimentation tank, and filtration equipment again. .

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of water treatment equipment showing one embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a precision filtration device in the same embodiment.

FIG. 3 is a schematic diagram showing the filtration action of the external pressure type ceramic filter in the same example.

FIG. 4 is an overall configuration diagram of a conventional water treatment device.

[Explanation of symbols]

21 Precision filtration device 22 Processing tank 23 Backwash water 24 External pressure type ceramic filter 25 Ceramic tube 26 Suction pump 27　Air diffuser 28 Blower device

Claims (1)

[Claims] Claim 1: Wastewater generated during the process of taking raw water from a water source, purifying the raw water through water purification processes such as mixing with chemicals, coagulating sedimentation, and filtration, and storing the purified treated water in a water purification pond. an external pressure type ceramic filter immersed in a treatment tank installed to treat A water treatment facility characterized by being equipped with a suction pump that communicates with the water treatment facility.