JPH0126759B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves filling a filler with aerobic microorganisms on its surface, flowing water to be treated containing BOD components from the bottom or top of the filler layer, and The present invention relates to a method for removing BOD components through microbial treatment by introducing air from the bottom of the filler layer.

In the conventional method for removing BOD components, a single packing material layer is formed in a fixed bed catalytic oxidation tank, and the water to be treated is introduced from the bottom or top of the packing material layer in such a fixed bed catalytic oxidation tank. At the same time, air is introduced from the bottom of the filler layer to remove BOD components, and the effluent water is introduced into a solid-liquid separation device such as a sedimentation device or flotation device to separate it from the filler material contained in the effluent water. Clear treated water is obtained by separating solids such as sludge, but if the filler layer becomes clogged, the treated water or treated water and air must be passed through from the bottom of the filler layer. The filling material layer is washed by flowing upwardly at a flow rate higher than that during water flow, and a large amount of cleaning waste water is generated during this washing at a flow rate higher than the processing flow rate during water flow. Regarding the treatment of the washing wastewater, if the washing wastewater is allowed to directly flow into the solid-liquid separator that processes the water effluent from the fixed bed contact oxidation tank during BOD component removal, the water volume load will rapidly increase and treatment will become impossible. Therefore, it is necessary to separately install a solid-liquid separation device such as a sedimentation device to treat washing wastewater.
The disadvantage is that the equipment cost increases. Furthermore, even if a solid-liquid separator is installed separately to treat washing wastewater, it is better to use a solid-liquid separator to treat runoff water during BOD component removal while the contact oxidation tank is being cleaned. This is still not desirable in terms of solid-liquid separation operations.

Furthermore, if cleaning wastewater and runoff water are to be treated using the same solid-liquid separator, a large-capacity intermediate storage tank should be installed before the solid-liquid separator in order to keep the water load on the solid-liquid separator constant. A disadvantage arises in that it must be provided.

The present invention solves the drawbacks of the conventional BOD component removal method by dividing the fixed bed catalytic oxidation tank into multiple chambers.
By performing washing separately for each chamber and making the total flow rate of water discharged from the tank approximately equal to the flow rate of washing wastewater in one room, the amount of washing wastewater that was previously required can be reduced. The purpose is to reduce equipment costs by omitting solid-liquid separation equipment for processing and intermediate storage tanks for cleaning wastewater that maintain a constant flow rate.

That is, in the present invention, a filler having aerobic microorganisms grown on its surface is filled, water to be treated containing BOD components flows in from the bottom or top of the filler layer, and air is discharged from the bottom of the filler layer. In the method of removing BOD components through microbial treatment, the tank is divided into multiple chambers with approximately equal cross-sectional areas, and the total processing flow rate of the multiple divided chambers and the cleaning flow rate of one chamber are A fixed bed catalytic oxidation tank is constructed in which the tank is divided so that the water is almost equal to each other, and a water supply pipe to be treated is provided at the bottom or top of each chamber, and an air supply pipe is provided at the bottom of each chamber. When the water to be treated becomes clogged with solid matter, excess microorganisms, etc. present in the liquid to be treated, the flow of water to each room is stopped, and then the flow of water to one of the rooms to be cleaned is stopped. The filler layer in the chamber is washed by supplying washing water with a flow rate equal to the total treatment flow rate of the plurality of chambers together with air in an upward flow, and then the washing waste water is subjected to the fixed bed catalytic oxidation process. It is characterized in that solid matter, excess microorganisms, etc. are removed from the washing wastewater, that is, BOD components are removed by processing it with a solid-liquid separator for water flow installed at the latter stage of the tank.

An example of an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing the flow of a fixed bed catalytic oxidation tank in which the BOD component removal method of the present invention is carried out, and FIG. 2 is a side cross-sectional explanatory view taken along line A-A' in FIG. . In these figures, 1 is a fixed bed catalytic oxidation tank having a filler layer 16 with aerobic microorganisms grown on its surface. three chambers T ₁ ,
In addition to dividing into T ₂ and T ₃ , the processing flow rate of the tank,
That is, the chambers are divided so that the total processing flow rate of the three divided chambers T ₁ , T ₂ , and T ₃ is approximately equal to the cleaning flow rate of one chamber, for example, T ₁ .

The total cross-sectional area of a fixed bed contact oxidation tank is
It is determined by a known method based on the BOD concentration, the flow rate of the water to be treated, the predetermined BOD volume load and the filler layer height,
The catalytic oxidation tank having this total cross-sectional area is divided so as to meet the above-mentioned conditions.

In addition, the filling material layer 16 of each chamber T ₁ , T ₂ , T ₃
Underneath, one or more air supply pipes 14 are buried at equal intervals on the same horizontal plane, and one or more to-be-treated water supply pipes 13 are buried on the horizontal plane slightly above the air supply pipe 14. Bury multiple pieces in the same way at equal intervals. Further, it is desirable that the treated water supply pipe 13 and the air supply pipe 14 be arranged at intervals so that they do not overlap in the vertical direction.

In addition, the treated water inflow pipe 2 having the treated water switching valve 3 and the raw water pump 4 is branched, and each chamber is
The treated water is connected to the treated water supply pipes 13 of T ₁ , T ₂ , and T ₃ via the treated water switching valves V ₁ , V ₂ , and V ₃ , and the treated water is transferred to the respective chambers T ₁ , T ₂ , and T 3 . Distribute equal flow rates into ₃ . Further, one end of the air inflow pipe 6 is connected to the blower 5, and the other end is branched to form the respective chambers T ₁ , T ₂ ,
Air switching valves X ₁ , X ₂ , X ₃ are installed in the air supply pipe 14 of T _3.
connect the air to each chamber T ₁ , T ₂ ,
Distribute equal flow into T ₃ .

A collection tray 15 for runoff water is provided above the filler layer 16 of the fixed bed contact oxidation tank 1, and a common solid-liquid separation device such as flotation separation is used to treat the tank 1 and the treated water and washing waste water of the tank 1. It communicates with the device 8 through an effluent discharge pipe 7. In addition, a treated water outflow pipe 11 is connected to the flotation separation device 8 via a storage tank 12, and a wash water switching valve 1 is connected to the storage tank 12 and the suction side of the raw water pump 4.
It communicates with the washing water pipe 9 through 0.

When treating water to be treated in the fixed bed contact oxidation tank 1, the water to be treated switching valve 3 and the switching valve V ₁ ,
V ₂ and V ₃ are opened, the raw water pump 4 is started, and the water to be treated is sent from the water inflow pipe 2 to the respective chambers T ₁ and
The water is distributed to T ₂ and T ₃ through the treated water supply pipe 13 at the same flow rate. For example, if the flow rate of the water to be treated passing through the raw water pump 4 per unit time is Q, then the water to be treated is caused to flow into each chamber T ₁ , T ₂ , T ₃ by Q/3. At the same time, air is pressurized by _the blower ₅ , and the pressurized air is sent from the air supply pipe ₁₄ to each chamber _T1 , _T2 ,
Evenly distribute and flow into T ₃ .

In this way, the water to be treated and air flow upward into the filling material layer 16 of each chamber T ₁ , T ₂ , T ₃ ,
BOD components in the water to be treated are removed by microbial treatment, and the effluent is introduced into the flotation separation device 8 from the effluent discharge pipe 7 via the water collection tray 15. In the flotation separator 8, solids such as sludge exfoliated from the filler present in the outflow water are separated, and the treated water is discharged from the treated water outflow pipe 11 via a small storage tank 12.

If water continues to flow for a certain period of time and microorganisms that have grown on the surface of the filling material in one of the multiple chambers T, for example chamber T ₁ , become enlarged and clog, the filling of chamber T ₁ will be interrupted. The material layer 16 is cleaned. When performing this cleaning, close the water switching valve 3 and
Stop the flow of the water to be treated into the chambers T ₁ , T ₂ , T ₃ , and close the switching valves V ₂ , V ₃ for the water to be treated. Next, the wash water switching valve 10 is opened, and the treated water from the flotation separator 8 is used as washing water to supply water to be treated from the storage tank 12 into the chamber T ₁ via the wash water pipe 9, the raw water pump 4, and the switching valve V ₁ . It is made to flow in from the pipe 13. At the same time, the air switching valves X ₂ and X ₃ are closed, and the pressurized air generated from the blower 5 is transferred to the chamber T ₁ via the switching valve X ₁ .
Ventilation is carried out from the air supply pipe 14 into the interior. In this way, the cleaning water and air are flowed upward into the filling material layer 16 in the chamber T ₁ to perform cleaning, and the cleaning waste water along with the sludge separated from the filling material layer 16 is transferred to the water collection tray 1.
5 and the effluent discharge pipe 7 to the flotation separator 8. In the device 8, sludge contained in the washing wastewater is separated to obtain treated water, and the treated water is circulated and used as washing water via the storage tank 12 and the washing water pipe 9.

As explained above, in the BOD component removal method of the present invention, the fixed bed catalytic oxidation tank 1 has two chambers T ₁ ,
so that the total processing flow rate of T ₂ and T ₃ and the cleaning flow rate of one chamber, for example, chamber T ₁ , are approximately equal.
Since it is divided into chambers T ₁ , T ₂ , and T ₃ with equal cross-sectional areas, the flow rate of cleaning water flowing into chamber T ₁ is therefore:
In the water flow process, the flow rate is equal to the total treatment flow rate Q of chambers T ₁ , T ₂ , T ₃ , that is, the other chambers T ₂ , T ₃
This will stop the flow into chamber T1 and allow it to flow only into chamber _T1 .
Cleaning water flows in at a flow rate approximately three times that of water flow, and pressurized air is also stopped from being supplied to other chambers T ₂ and T ₃ .
Since ventilation is carried out only in chamber T ₁ , the flow rate is approximately three times that when water is flowing, and the filling material layer 16 in chamber T ₁ is vented.
In addition, a constant flow rate of runoff water or cleaning waste water can be discharged from the tank 1 through the water passage process and the cleaning process.

After completing the cleaning of chamber T ₁ , the water flow process is started again, and the water to be treated and air are supplied to each chamber T ₁ , T ₂ , and T ₃ in the same manner as in the water flow process described above. to remove BOD components from the water being treated. In addition, water flow continues for a certain period of time, and the chambers _T1 , _T2 , _T3
Filler layer 1 of one of the chambers, for example chamber T ₂
When clogging occurs in chamber T 6, the flow of water to be treated is stopped, and cleaning is performed by allowing cleaning water and air to flow only into chamber T ₂ in the same manner as in the cleaning process described above. In this way, the filler layer 16 of the tank 1 is cleaned.
Separate the chambers T ₁ , T ₂ , T ₃ and clean only one chamber T in one cleaning process,
In each cleaning process, the cleaning of the respective chambers T ₁ , T ₂ , and T ₃ is performed in a circular manner.

The present invention is applicable to BOD as explained in the embodiment.
Needless to say, the present invention is not limited to a fixed bed catalytic oxidation tank in which the water to be treated containing components flows in from the bottom of the filler layer, but can also be applied to a fixed bed catalytic oxidation tank in which the water to be treated flows in from the top of the filler layer. .

According to the method for removing BOD components of the present invention, a fixed bed catalytic oxidation tank is divided into a plurality of chambers having approximately equal cross-sectional areas, and the total treatment flow rate of the plurality of divided chambers and the flow rate of one chamber are Divide the tank so that the cleaning flow rate is approximately equal, install a water supply pipe to be treated at the bottom or top of each chamber, and an air supply pipe at the bottom of each chamber, and perform cleaning separately for each chamber. As a result, almost the same flow rate of treated water and cleaning wastewater are discharged from the tank through the water flow process and the cleaning process, and a constant flow rate of treated water is continuously discharged to a solid-liquid separator such as a flotation separator installed at the subsequent stage. and cleaning wastewater can flow in. This eliminates the need to separately install a solid-liquid separator for treating washing wastewater, unlike in the past, and eliminates the need to provide an intermediate storage tank for washing wastewater to keep the flow constant. Since the flow rate of the wash water flowing into the tank is almost the same as the flow rate of the water to be treated, there is no need to separately provide a pump for the wash water, and equipment costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the flow of an embodiment of a fixed bed catalytic oxidation tank for carrying out the BOD component removal method of the present invention, and FIG.
FIG. 3 is a side cross-sectional explanatory view taken along line A'. 1... fixed bed contact oxidation tank, 2... treated water inflow pipe, 3... treated water switching valve, 4... raw water pump,
5...Blower, 6...Air inflow pipe, 7...Outflow water discharge pipe, 8...Flotation separation device, 9...Washing water pipe, 10...Washing water switching valve, 11...Treatment water outflow pipe, 12 ...Storage tank, 13...Water supply pipe to be treated, 1
4...Air supply pipe, 15...Water collection tray, 16...
...Filler layer, T...chamber, V...switching valve for water to be treated, X...switching valve for air.

Claims (1)

[Claims] 1. Fill with a filler with aerobic microorganisms on its surface, and then fill with a filler from the bottom or top of the filler layer.
In addition to inflowing treated water containing BOD components,
In a method in which air is introduced from the bottom of the filler layer and BOD components are removed by microbial treatment,
The tank is divided into multiple chambers with approximately equal cross-sectional areas, and the tank is divided so that the total processing flow rate of the multiple divided chambers is approximately equal to the cleaning flow rate of one chamber, and A fixed-bed contact oxidation tank is constructed with a water supply pipe to be treated at the bottom or top and an air supply pipe at the bottom of each chamber, and the filler layer is designed to prevent solid matter and excess microorganisms present in the liquid to be treated. When the blockage occurs, the flow of water to be treated to each chamber is stopped, and then a flow rate equal to the total flow rate of the multiple chambers when water is flowing is placed in one chamber to be cleaned. Cleaning the filler layer in the chamber by supplying cleaning water with air in an upward flow, and then
A BOD component characterized in that unique substances, surplus microorganisms, etc. are removed from the washing wastewater by treating the washing wastewater with a solid-liquid separator for water flow installed after the fixed bed contact oxidation tank. How to remove.