JPH0642793Y2 - Aerobic immersion ▲ Floor ▼ Floor equipment - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is a biological treatment for extremely effectively purifying organic sewage containing BOD, SS, etc. such as sewage, night soil sewage, and various organic industrial wastewater. It relates to the device.

[Conventional technology]

2. Description of the Related Art Conventionally, the aerobic submerged bed apparatus shown in FIG. 2 is widely known (see Pollution and Countermeasures Magazine Vo1.20, No. 13, pp 41-46 (84)). This conventional device has an anthracite, granular activated carbon, various granular minerals, plastic particles,
Packed layer of any granular material such as granular sponge (immersion bed 22
Is provided, and an air diffusing pipe 23 is provided below the immersion floor 22.
Is provided.

Then, the organic sewage (raw water) flows into the tank 21 from the settling tank 24 through the raw water inflow pipe 25 and flows downward or upward in the immersion bed 22 (in the case of downward flow in FIG. 2). At the same time, the microbes on the surface of the granular material and the air blower 26 come into contact with the air bubbles diffused through the air diffuser 23, and BOD is removed,
The raw water SS is also excessively removed and becomes treated water, and reaches the treated water tank 28 through the treated outflow pipe 27. As such a treatment is continued, the SS trapped in the immersion bed 22 and the increase in the amount of microorganisms increase the over resistance and make it difficult to continue the treatment. The treated water is supplied to the lower part of the immersion floor 22 by the cleaning pump 29 to clean the immersion floor 22.

The cleaning drainage of the immersion floor 22 is passed through the cleaning drainage tank 30 and settling tank 24.
And SS are separated by sedimentation, and the total amount of the raw water and the flow rate of washing waste water is again supplied to the immersion bed 22.

A blower 31 for cleaning is connected to the backwash air pipe 32.

[Problems to be solved by the device]

However, the conventional device shown in Fig. 2 exhibits excellent performance when the raw water SS and BOD are at low concentrations.
If the BOD is high, the degree of clogging of the immersion bed 22 is large and the increase in overresistance is rapid, so the cleaning frequency of the immersion bed 22 must be frequent (for example, 4 to 5 times a day). However, since the water for cleaning the immersion floor 22 must use the treated water (in all the conventionally known immersion bed apparatuses, the treated water is used to wash the immersion floor without exception). The treated water production decreases in direct proportion to the cleaning frequency of, for example, Qm ³ / day of raw water
Even if biological treatment is carried out at, only treated water of about 0.5 to 0.6 Qm ³ / day can be obtained. Therefore, when the raw water BOD and SS are extremely high in concentration, even if the raw water is passed through Qm ³ / day, only treated water of 0.1 Qm ³ / day or less is obtained, and the remaining treated water is 0.9 Qm ³ / day. All the days or more will be consumed as water for cleaning the immersion floor 22.

As a result, in conventional immersion bed equipment, for example, raw water BOD200
It could not be applied to raw water above 100 mg / l and SS100 mg / l, and its application range was extremely narrow. This is the biggest drawback of the conventional device,
If the raw water BOD is high, other biological treatment means (such as activated sludge) must be installed in front of the immersion bed device, and if the raw water SS has a high concentration, as shown in Fig. 2, the immersion bed device is used. Settling basin 24 etc. had to be installed in the previous stage, and the installation area and construction cost were high.

Also, the amount of cleaning water (Q _W ) when the immersion floor 22 is clogged is
Since it requires twice the floor volume (V _M ), that is, Q _W = 2 V _M , the treated water storage tank 28 (washing water storage tank) has a volume of 2 V _M (m ³ ).
Therefore, there was a serious irrationality that the cleaning drainage tank 30 with a volume of 2 V _M (m ³ ) was required, and the installation area of these tanks became larger than the immersion floor device main body.

The present invention aims to completely solve the above-mentioned drawbacks of the conventional apparatus. Specifically, even a high concentration of organic sewage can be extremely easily dealt with only by the immersion bed apparatus. In this way, it is possible to eliminate the need for providing another pretreatment step (that is, a step of reducing the load on the immersion bed) in the preceding stage of the immersion bed (a large expansion of the application range).

Do not waste any clarified treated water for cleaning the submerged floor (significantly improved treated water production efficiency).

Eliminate the need for a large-capacity cleaning drainage storage tank and cleaning water storage tank.

Significant savings in construction costs and footprint.

It is an object.

[Means for Solving the Problems]

The present invention relates to an aerobic immersion bed apparatus in which an immersion bed filled with a granular material is provided in a tank provided with a raw water inflow section and a treated water outflow section, and an oxygen-containing gas diffuser is provided below the immersion bed. An aerobic submerged bed apparatus comprising: a washing means for communicating the washing drainage outflow passage of the submerged bed with a solid-liquid separator, and pumping the separated water of the solid-liquid separator under the submerged bed. The aerobic submerged bed apparatus is characterized in that a replenishing means for replenishing a part of the treated water flowing out from the treated water outflow portion to the separated water of the solid-liquid separator is attached.

[Action]

As shown in FIG. 1, the function of the present invention having the above-described structure is that the raw organic water (there is no problem even if the concentration of BOD and SS is high) flows into the upper part of the tank 1 and flows downward. By flowing down in the immersion bed 4 and contacting the air bubbles discharged from the air diffuser and the biofilm, soluble BOD is removed and SS is also excessively removed. Then, clear treated water from which BOD and SS have been highly removed from the bottom of the tank 1 flows out from the treated water outflow pipe 3.

If such a process is continued, the over-resistance reaches the set value at a certain point, so that the immersion floor 4 is washed at that point. Washing is performed as follows. That is, the raw water is stopped, the cleaning air is supplied, the water in the cleaning water storage tank 11 is pressure-fed to the lower part of the immersion bed 4 by the cleaning pump 12, and the granular material of the immersion bed 4 is expanded and fluidized to wash out SS. Washing wastewater containing a large amount of SS flows out from the upper part of the tank 1 through the washing drainage pipe 8, a polymer flocculant is injected as needed, and the flocs generated are rapidly separated in the solid-liquid separation device 9, and SS10 About 15 mg / l of clear separated water is obtained and reused as washing water.

In this way, the most important essence of the present invention lies in a closed system configuration in which the cleaning wastewater itself of the immersion floor 4 is supplied again as cleaning water for the immersion floor 4 and reused.

Depending on the amount of sludge discharged from the solid-liquid separator 9, the treated water storage tank
From 15, it is preferable that a small amount of clear treated water can be supplied to the washing water.

Then, the amount of SS in the cleaning drainage became small (immersion floor 4
(Which means that the washing was performed sufficiently), the washing pump 12 is stopped, raw water is supplied again, and the biological treatment is restarted.

If it is not desirable to stop the supply of raw water during the cleaning of the immersion floor 4, it is preferable to arrange a plurality of immersion beds 4 side by side and stagger the cleaning time so that the raw water can always be supplied to one of the immersion beds. Is.

Further, in the present invention, it is not necessary to provide a conventional settling tank or a step for removing BOD in advance in the preceding stage of the immersion bed 4, but in the sense that such a pretreatment step should not be provided. Of course, it does not matter if it is provided. In particular, in the case where existing equipment can be effectively used, it goes without saying that a pretreatment process may be provided to reduce the frequency of cleaning the immersion floor 4.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. 1. An anthracite, various kinds of granular minerals and granular activated carbon are contained in a tank 1 having a raw water inflow pipe 2 at the upper part and a treated water outflow pipe 3 at the lower part. When the submerged bed 4 filled with plastic particles or any other granular material is used and a sedimentable granular material having a specific gravity of 1.0 or more is used, the lower part of the submerged bed 4 is supported by a supporting member 5 to In the case of using the floating granular material of less than 1.0, a porous water-permeable member 5'such as a net for preventing the floating granular material from flowing out is provided on the upper part of the immersion bed 4. An air diffuser 6 for aeration is provided under the support member 5 or the floating submerged floor, and is connected to an air blower 7.

In the first illustrated example, the raw water that has flowed into the tank 1 from the raw water inflow pipe 2 flows down in the tank 1 in a downward flow, becomes treated water, and flows out of the tank 1 from the treated water outflow pipe 3. However, the upper and lower positions of the raw water inflow pipe 2 and the treated water outflow pipe 3 are reversed from the illustrated example so that the raw water flows downward in the tank 1 as treated water and then flows out from the upper part. You can also do it.

Further, a cleaning drainage pipe 8 is opened in the upper part of the tank 1, and this cleaning drainage pipe 8 is connected to a solid-liquid separation device 9. As the solid-liquid separator 9, a sedimentation tank type is shown in the illustrated example, but means such as flotation, membrane separation, screen separation, centrifugal separation, and superseparation can also be adopted.
The separated water outflow pipe 10 of the solid-liquid separation device 9 is connected to a cleaning water storage tank 11, and this cleaning water storage tank 11 is connected via a cleaning pump 12 to the tank 1
Are connected to the bottom of.

13 is a polymer coagulant injection pipe connected to the washing drain pipe 8,
Reference numeral 14 denotes a sludge discharge pipe of the solid-liquid separator 9.

A treated water storage tank 15 for storing treated water flowing out from the treated water outflow pipe 3 is provided, and the treated water storage tank 15 and the solid-liquid separation device 9 are provided.
It is preferable that the separated water outflow pipe 10 or the cleaning water storage tank 11 is connected by a pipe 16 so that the treated water is supplied to the cleaning water.

[Effect of device]

As described above, according to the present invention, the following extremely important effects can be obtained.

It is not necessary to use the clear treated water produced by the aerobic submerged bed equipment as cleaning water for the submerged bed, the cleaning drainage is continuously clarified, and the system is reused again as cleaning water. Therefore, even if the raw water BOD, SS has a high concentration, the treated water production efficiency, that is, (the treated water amount /
The raw water flow rate) does not deteriorate, and effective treatment is possible without any problems. As a result, the target raw water applicable to the aerobic submerged bed apparatus, which has been conventionally applicable only to low-concentration BOD and SS raw water, is greatly expanded.

Even when the raw water BOD is at a high concentration, it is not necessary to provide a separate biological treatment step before the aerobic submerged bed unit as in the conventional case, and even when the SS is at a high concentration, it is not necessary to provide a raw water settling tank. Therefore, the equipment construction cost and the installation area are significantly reduced, and an extremely large-capacity cleaning water storage tank and cleaning drainage storage tank are not required, and the installation area and construction cost are significantly reduced.

Since the amount of washing wastewater is much smaller than the amount of raw water inflow, the solid-liquid separation device for treating the washing wastewater to obtain clear washing water is compact, and the construction cost is low.

The sludge discharged from the solid-liquid separation device for washing wastewater has a very good dewatering property, and can be dehydrated as it is without providing a new dewatering aid.

Since the amount of cleaning wastewater is not added to the raw water, the load on the aerobic immersion floor device is reduced (in the conventional device,
Since the amount of washing wastewater is added to the amount of raw water inflow,
Large water flow load).

In the conventional device, the treated water production efficiency and the (treated water amount / raw water treated amount) ratio decrease in direct proportion to the cleaning frequency (times / day) of the submerged bed. High treated water production efficiency can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a vertical sectional view showing a conventional example. 1,21 ... Tank, 2,25 ... Raw water inflow pipe, 3,27 ... Treated water outflow pipe, 4,22 ... Immersion bed, 5 ... Support member, 5 '... Porous water-passing member, 6,23 ... Diffuser pipe , 7,26 ... Air blower, 8 ... Wash drainage pipe, 9 ... Solid-liquid separation device, 10 ... Separation water outflow pipe, 11 ... Wash water storage tank, 12, 29 ... Wash pump, 13 ... Polymer flocculant injection pipe, 15, 28 ... Treated water storage tank, 16 ... Piping, 24 ... Sedimentation tank, 30 ... Washing drainage tank, 31 ... Washing room blower, 32 ... Backwash air pipe.

Claims (2)

[Scope of utility model registration request] 1. An aerobic immersion bed apparatus in which a dipping bed filled with a granular material is provided in a tank provided with a raw water inflow section and a treated water outflow section, and an oxygen-containing gas diffuser is provided below the immersion bed. The aerobic immersion floor, wherein the cleaning drainage outflow passage of the immersion bed is connected to a solid-liquid separation device, and a cleaning means is provided for pumping the separated water of the solid-liquid separation device to the lower part of the immersion bed. apparatus. 2. The aerobic submerged bed apparatus according to claim 1, further comprising replenishing means for replenishing a part of the treated water flowing out from the treated water outflow portion to the separated water of the solid-liquid separation device.