JPH0123529Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a wastewater filtration device that can continuously capture and remove pollutants, and is designed to handle fluctuations in the concentration of pollutants in raw water (for example, papermaking white water wastewater) during paper manufacturing. Regardless,
This is a wastewater filtration device that can stably and continuously remove pollutants.

[Prior art]

Sand filters, ie, sand filtration devices, purify wastewater by passing a layer of sand from above to below, and have been used in water treatment for a long time. However, with conventional sand filters, after a certain period of operation, the operation had to be temporarily interrupted and backwashed in order to restore the filtration capacity.

As a countermeasure to this problem, there is an upflow type solid-liquid fluidized bed type filtration device that can perform filtration and cleaning at the same time by flowing the sand in the lower layer to the upper layer. For example, there is a continuous sand filtration device disclosed in Japanese Patent Application Laid-Open No. 56-65696.

However, these devices have the disadvantage that when the raw water concentration fluctuates, the sand filtration layer may be prematurely clogged at high concentrations. For example, when papermaking white water wastewater is filtered using a conventional continuous upward flow sand filtration device and the filtrated water is reused, when the white water concentration fluctuates widely (e.g. 20 to 150 ppm) and when the concentration is high (100 to 150 ppm), The sand filtration layer may become clogged, and the sand layer and pollutants may float to the surface, making filtration impossible.

In this case, it is generally necessary to lower the amount of supplied white water (supplied raw water amount) by operating a valve to reduce the load on the sand filtration layer and stabilize the filtrate concentration, so workers must constantly monitor and operate the valve. The disadvantage is that you have to do

[Purpose of invention]

The purpose of this invention is to eliminate the above drawbacks, maintain the pressure loss level difference so that stable filtration can be continued even when the raw water is highly concentrated, and automatically branch the raw water when the pressure exceeds that level. The purpose is to keep the load on the sand filtration layer constant by methods such as dividing the flow into channels. This prevents clogging of the filter layer.

[Structure of the idea]

In order to achieve the above object, the present invention is a wastewater filtration device in which a load pressure regulating device is provided in the pipe line between the filtration bed, that is, the inlet of the upflow type solid-liquid fluidized bed and the raw water supply device.

Load pressure can be adjusted by providing an overflow weir having a predetermined head in a branch flow path of the pipeline. Further, the load pressure can also be adjusted by a combination of a variable throttle valve provided in the pipe and an overflow weir provided in a branch flow path provided in front of the variable throttle valve and having a predetermined head.

Preferably, the overflow weir has an adjustable head height and includes a weir plate that is slidable up and down.

As the upflow type solid-liquid fluidized bed type wastewater filtration apparatus main body itself, a conventionally known one can be used.

[Mode of implementation]

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

An example of a wastewater treatment device used in the present invention has a sand filter layer 1, a raw water supply nozzle 2 and an air feed pipe 3 installed below the sand filter layer, and a bottom opening 4 near the air feed pipe 3. A drainage pipe 5 that penetrates the sand filter layer 1 and separates sand and pollutants in a filter sand and pollutant separation labyrinth section 23, and then drains the pollutants.
connected to. In addition, a sand layer 6 containing pollutants, an air lift pipe 7 for separating sand and pollutants, a filtrate extraction pipe 8 for taking out the filtrate at the top, a raw water supply nozzle 2 and a raw water supply pump 9. This is a drainage filtration device having a branch pipe 10 provided in between, and an overflow weir 11 provided in the branch pipe 10 and having an adjustable head height for adjusting the water level (FIGS. 1 and 2). The head height of the overflow weir 11 is adjusted by adjusting the variable weir plate up and down.

Another configuration is a wastewater filtration device having an overflow weir 11 having a predetermined head height and a variable throttle valve 19 provided in front of the raw water supply nozzle 2 (FIG. 3). In this case, pressure drop water level difference △
h is Δh=Δh1 (internal pressure)+Δh2 (pressure loss due to variable throttle valve), and the pressure drop water level difference Δh is determined by the variable throttle valve.

The outlet of the branch pipe 10 may be returned to the tank 14 for raw water such as white water, or may be disposed of and entrusted to another wastewater treatment system. In addition, 16 is a check valve,
15 is a flow meter.

[Effect]

The present invention has the following effects based on the above configuration.

In Fig. 1, raw water (papermaking white water, wastewater containing SS, etc.) 13 is transferred to a sand filter 12 in a raw water tank 1.
4 with a raw water supply pump 9, a flow meter 15,
Raw water is supplied from the raw water supply nozzle 2 into the casing 17 from below the sand filtration layer 1 via the check valve 16.
When the raw water 13 flows upward through the sand filter layer 1,
The pollutants in it are trapped in the sand. The sand that has captured the pollutants settles and becomes dirty sand 6. Air 18 is sent from the air feed pipe 3, and sand containing air and dirt is lifted up from the bottom opening 4 through the air lift pipe 7. The rising sand is washed as it descends,
The wastewater containing pollution is discharged to the outside through a drainage pipe 5. On the other hand, the filtrated water that has passed through the sand filtration layer 1 upward and from which contamination has been removed is recovered through the filtrated water extraction pipe 8 and used again as industrial water.

In this filtration device, when the raw water concentration increases, the water flow resistance of the filtration device increases. When it rises, the raw water supply is suppressed, and raw water that exceeds the load specified by the height of the weir plate of the overflow weir is automatically released through the branch channel. The released raw water may be returned to the raw water tank 14 or may be sent to another wastewater treatment route. It is desirable that the overflow weir 11 be able to easily adjust the water level and be easy to maintain. A preferred example is shown in FIG. The desired pressure loss water level difference (△h) can be achieved by simply raising and lowering the weir plate in the center of the weir.
can be freely selected. When the raw water becomes highly concentrated and causes a pressure drop of △h or more, a portion of the raw water is discharged through the branch pipe to keep the load on the sand filter layer constant.

The above explanation is based on the case where the raw water is papermaking white water, but other wastewater containing SS (suspended solids) can also be used as the raw water.

The same effect can also be obtained by the load pressure adjusting device shown in FIG. The variable throttle valve 19 is throttled according to the water flow resistance during steady operation, and functions to divert a portion of the raw water to the branch flow path when the resistance increases. The overflow weir (fixed head height) of the branch channel may be provided at a height sufficient to be used to overflow excess raw water. It is also possible to use the overflow weir shown in FIG. 1 together with the variable throttle valve 19 shown in FIG. 3.

In addition, such flow rate adjustment is possible using the raw water supply nozzle 2.
A pressure control valve 21 installed in the pipeline between the raw water supply pump 9 and the raw water supply pump 9, and a pressure gauge (pressure detection device) installed downstream of the pressure control valve 21.
20. This can also be achieved by controlling the pressure control valve 21 provided in the branch flow path 10 using a control instrument 22 (pressure display) that controls the valve opening degree based on the output pressure value of the pressure gauge 20. Note that branch flow path 1
After the branch point 0, the line is provided with a throttle valve 24 (manual adjustment). In this case, a configuration with branch piping (FIG. 4) and a configuration without it (FIG. 5) are possible.

However, in the case of this device, the pressure fluctuations that need to be detected are small, and a control device that can accurately measure and control this would be a little expensive, but would be suitable for large-scale devices. . Although it is more difficult in terms of maintenance and management than the methods shown in Figures 1 and 3,
3 has the advantage that even for a relatively small device, the structure is simple, low cost, and easy load pressure control and maintenance management are possible.

〔Example〕

Papermaking white water (concentration: 20 to 100 ppm) was filtered using the sand filter device 12 shown in FIG. 1 to obtain filtrate water. The pressure loss water level difference at this time was 300 to 350 mmAq. Therefore, a load water level difference of 350 mmAq from the upper surface of the filtration water level was maintained at the water level adjustment overflow weir 11 using the branch pipe 10, and the white water concentration was increased to 100 to 500 ppm. As the concentration of white water increases, white water corresponding to the increased load escapes from the branch pipe 10, and the load on the sand filtration layer is automatically kept constant, making it possible to always obtain filtered water of 5 ppm or less. The diameter of the fluidized bed section is 1.5m.
× A filtration device with a height of 1.0 m was able to stably process 330 tons of white water (average concentration 60 ppm) per day.

When a comparison operation was conducted under the same conditions without using branch pipes and overflow weirs, blockage occurred within a few hours, the ppm of the treated water increased, and filtration became impossible.

[Effect of idea]

As mentioned above, in response to fluctuations in raw water concentration, with conventional sand filtration equipment, the amount of raw water supplied must be increased or decreased by operating valves, which is cumbersome and extremely difficult to adjust the flow rate when the raw water concentration changes. It is.
In particular, instruments such as simple flowmeters are not suitable for high concentration wastewater. On the other hand, in the waste water filtration device of this invention,
Load fluctuations on the sand filtration layer are automatically controlled by adjusting the pressure drop water level difference, and stable, clear filtered water can be obtained at all times. Furthermore, there is an effect that there is no need for workers to monitor or increase or decrease the amount of raw water to be supplied. Not only in comparison with conventional methods, but also in comparison with other conceivable control methods such as flow rate regulation, the present invention has a unique effect in that it has a simple structure and can obtain stable effects.

[Brief explanation of the drawing]

FIGS. 1, 3, 4, and 5 are schematic system diagrams of each embodiment of the wastewater filtration device according to the present invention. Also, Figure 2 shows overflow weir 1 for water level adjustment.
1 side sectional view (Fig. 2A) and front sectional view (Fig. 2
Figure B). 1...Sand filter layer, 2...Raw water supply nozzle, 3...
... Air supply pipe, 4 ... Bottom opening, 5 ... Drainage pipe, 6 ... Sand layer containing pollutants, 7 ... Air lift pipe, 8 ... Filtered water extraction pipe, 9 ... Raw water supply pump, 10... Branch pipe, 11... Overflow weir for water level adjustment, 11a... Weir plate, 12... Sand filter device, 13... Raw water, 14... Raw water tank,
15...Flowmeter, 16...Check valve, 17...
Casing, 18... Air, 19... Variable throttle valve, 20... Pressure gauge, 21... Pressure control valve, 22
...Pressure display control instrument, 23...Labyrinth part,
24... Throttle valve.

Claims (1)

[Scope of claims for utility model registration] (1) In an upflow solid-liquid fluidized bed wastewater filtration device,
A wastewater filtration device that has a load pressure adjustment device in the pipeline connecting the raw water supply device and the fluidized bed inlet. (2) The wastewater filtration device according to claim 1, wherein the load pressure regulating device is an overflow weir provided in a branch flow path of the pipeline and having a predetermined head. (3) The drainage according to claim 1, wherein the load pressure regulating device comprises a variable throttle valve provided in the pipe line and an overflow weir provided in a branch flow path in front of the valve and having a predetermined head. Filtration device. (4) The drainage filtration device according to claim 2, wherein the overflow weir includes a height-adjustable weir plate. (5) The load pressure adjustment device is a pressure control valve disposed in a branch passage of the pipeline, and the branch passage is disposed in the pipeline in front of a throttle valve, and the pressure control valve The wastewater filtration device according to claim 1, wherein is controlled by a pressure detection device disposed in the conduit after the throttle valve. (6) The waste water filtration device according to claim 1, wherein the load pressure regulating device is a pressure control valve controlled by a pressure detection device disposed downstream of the pressure control valve on the pipeline.