JPS5854878B2 - Back cleaning method for contact “filter” material in sewage immersion “filter” floor treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for backwashing contact furnace materials in a sewage immersion hearth treatment method in which sewage is purified by the action of aerobic microorganisms.

In the immersion hearth treatment method for sewage, a contact furnace material for oxidation and purification of sewage is placed in the treatment tank, and air is pumped through a circulation diffuser or mechanical agitation installed below the air lift section in this tank. By circulating the blown contact furnace material, microorganisms in the wastewater settle on the surface of the contact furnace material and multiply.

These proliferating microorganisms oxidize BOD in the wastewater, capture suspended solids, and purify the wastewater.

In this way, during sewage purification, organisms adhere to the surface of contact reactor materials,
It proliferates and becomes a biofilm.

When the thickness of this biofilm reaches a certain level, the biofilm on the surface that is in contact with the circulating flow of wastewater is likely to be peeled off due to the shearing action of the circulating flow, and the deep biofilm that is in contact with the surface of the contact reactor material is likely to be peeled off. As the thickness of the biofilm increases, it becomes difficult to supply oxygen and the biofilm becomes anaerobic, reducing its adhesive strength to the contact reactor material, which causes the biofilm to gradually peel off from the surface of the contact reactor material.

The biofilm that has come off in this way gets mixed into the wastewater, leading to deterioration of water quality.

To prevent this, air diffusers are installed below the contact reactor material in anticipation of the situation in which the growth of this biofilm reaches a certain level, the purification ability decreases, and the biofilm peels off from the contact reactor material. Manually open the valve of the backwashing air pipe connected to the equipment and blow air from below the contact furnace material into the furnace material from the cleaning air diffuser, thereby stripping and removing the microbial film on the surface of the furnace material. This detached biofilm becomes sludge and settles at the bottom of the tank, and is discharged from the tank through the sludge pipe.

In this way, based on experience, cleaning of contact furnace materials should be done manually or
Alternatively, the backwashing interval is set in terms of time, and the titer is operated to forcefully perform the washing.

However, this backwashing of contact reactor materials is performed on the assumption that biofilm has grown on the swamp material more than necessary, so backwashing is not always carried out when necessary, and it is often the case that detached biofilms occur. Even if the wastewater becomes even more contaminated, it may not be backwashed and used with reduced purification ability.

In view of this, the present invention eliminates the need for manual operations, automatically backwashes the contact reactor material at the time when the proliferating microorganism film peels off or is about to occur, and at the same time settles to the bottom of the tank. Sludge is also removed, and the present invention will be described below with reference to the illustrated embodiments.

In the figure, 1 is a sewage purification treatment tank, in which sewage is supplied from the top through a sewage inflow pipe 2, and a treated water outflow pipe is installed at a different position from the sewage supply position, preferably on the opposite side farthest from the inflow position. From 3, the purified water should be drained.

In addition, in this septic treatment tank 1, a contact furnace material 4 and a circulation diffuser 5 are provided at the bottom of the air list section 17, and at the lower position of this contact furnace material 4, unnecessarily proliferate on the surface of the contacted materials. A cleaning air diffuser 6 is provided so that biofilm can be peeled off and removed over substantially the entire contact furnace material.

An air pipe 8 having a valve 7 is connected to the air diffuser 6, and air for backwashing is blown out from the air diffuser 6 through the air pipe 8 and valve T from a blower 9, a compressor, an air tank, etc. At the same time, this valve 7 is equipped with a mechanism that automatically opens and closes using an electromagnetic opening/closing type or an air opening/closing type. Sensor 1 for measuring solids concentration
0, a signal transmitter 11 is connected to the sensor, and the signal transmitter 11 and the valve are electrically connected to open and close the valve in response to a signal from the sensor.

In this case, the valve 7 is provided with a signal receiver 12.

Further, a sludge storage section is formed at the bottom of the septic tank 1, and a sludge drainage pipe 13 is connected to this sludge storage section.
A sludge concentration meter 14 and a sludge discharge valve 15 are installed vertically in the sludge concentration meter 14 and a sludge discharge valve 15, respectively, and the signal is electrically connected to receive the signal from the sludge concentration meter 14 and the signal from the sensor 10 to the sludge discharge valve 15. A receiver 16 is provided, and the mud draining valve 15 is opened and closed by the action of the signal receiver 16.

In the sewage purification treatment tank constructed as described above, the sewage supplied from the sewage inflow pipe 2 is supplied with oxygen into the sewage by the air blown into the sewage by the circulation diffuser 5. A water flow is generated in the tank as shown by an arrow, and the wastewater circulates through the contacted materials, where it is purified by aerobic microorganisms.

The purified treated water is then allowed to flow out of the tank from the outflow pipe 3.

The concentration of suspended matter or solid matter in the circulating wastewater during purification is measured by the sensor 10, and when it exceeds a certain value, a signal is transmitted from the signal transmitter 11, this signal is received by the receiver 12, and the valve 7 The blower 9 sends air through the air pipe 8 to the cleaning air diffuser 6 and injects it toward the contact reactor material to forcibly peel off and remove the excess biofilm that has grown and settle it in the sludge storage section.

After a certain period of time has passed and the sludge has accumulated in the sludge storage section, the sludge discharge valve is opened to discharge the sludge from the sludge storage section.

At this time, the sludge concentration meter detects a high concentration at the beginning of sludge drainage, and as time passes, the concentration shifts to a low concentration.

When the concentration reaches a certain low level, the concentration meter issues a signal, closes the sludge removal valve, closes the air valve, and completes the series of backwash operations.

The contact material suddenly dies due to contamination with harmful substances in wastewater, etc.
If the water quality in the treatment tank suddenly deteriorates due to peeling from the surface of the contact material, the sensor 10 sends a signal to the signal receiver 16 of the sludge valve 15 to open the sludge valve 15 and remove the water inside the treatment tank. sewage is discharged outside the tank, and the sewage inside the tank is renewed.

According to the present invention, a sensor is installed in the sewage circulation flow path that circulates through the lubricant in the tank, and this sensor measures the concentration of turbidity or solids in the sewage, and issues a signal when it reaches a certain value or more. Since the air valve for backwashing is opened and air is injected from the air diffuser to clean the contact reactor materials, the contact reactor materials are always cleaned automatically and at the most effective time, so there is no need to waste water. It has advantages such as efficient purification of sludge and automatic sludge discharge.

[Brief explanation of the drawing]

The drawing is a schematic longitudinal sectional view illustrating the invention in detail. 1... Septic tank, 2... Sewage inflow pipe, 3... Treated water outflow pipe, 4... Contact p
material, 5... air diffuser for circulation, 6... air diffuser for cleaning, 7... valve, 8... air pipe, 9... ...Blower, 10...Sensor, 11...Signal transmitter, 12,16...
・Signal receiver, 13...Sludge removal pipe, 14...
...Sludge concentration meter, 15...Sludge valve, 17...
...Air lift section.

Claims (1)

[Claims] 1. The concentration of turbidity or solid matter in the circulating wastewater is measured with a sensor installed in the wastewater purification tank, and the concentration is kept constant. When the value exceeds the value, the air valve is opened and the cleaning air diffuser blows air towards the contact F material to clean it, and the signal from this sensor and the sludge concentration meter installed in the sludge pipe are connected. 1. A method for backwashing contact reactor materials in a sewage immersion bed treatment method, characterized in that sludge is removed by selectively opening and closing a sludge valve.