JPH07100156B2 - Organic wastewater biological treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to organic sewage containing BOD, SS, etc., particularly sewage containing high concentrations of BOD, SS, etc., human waste sewage, various industrial wastewater, etc. The present invention relates to a biological treatment apparatus suitable for effective treatment of organic wastewater.

[Conventional technology]

Conventionally, as a biological treatment apparatus for organic wastewater, a submerged aerobic bed apparatus provided with a bed filled with a granular material having a specific gravity of 1.0 or more such as anthracite, sand, and granular activated carbon has been known. This device allows raw water to flow in a downward flow while aerating from the lower part of the floor, and simultaneously performs the treatment with a highly aerobic biofilm in the bed.

[Problems to be Solved by the Invention]

Such a conventional submerged aerobic biological bed apparatus is extremely efficient for treating sewage with low SS and BOD, but organic sewage with a high SS concentration in the inflow water, such as raw sewage. In this case, the floor was severely clogged, frequent material cleaning was required, and SS's excessive function declined. For this reason,
Conventionally, a sedimentation basin had to be installed in front of the aerobic biological bed apparatus to remove SS in wastewater to a certain level or less in advance.

However, in the precipitation method, the removal rate of SS is not high.

 The setting area of the sedimentation basin is large.

Although SS can be removed, soluble BOD cannot be removed at all.

There were problems such as.

The present invention accurately solves such conventional problems, and SS
It is an object of the present invention to provide a biological treatment apparatus for organic sewage capable of exhibiting a sufficient treatment function even for organic sewage having a high BOD concentration.

[Means for Solving the Problems]

In the present invention, in order to achieve the above-mentioned object, a floating filter material layer is held in an upper part of a tank, an air diffuser is provided inside or under the floating filter material layer, and a lower part of the tank is used as a precipitation part. A treatment tank provided with a raw water inflow section in the precipitation section and a primary treated water outflow section in the upper section of the tank, and an aerobic biological filter apparatus provided with a filter bed of granular filter medium having a specific gravity of 1.0 or more are installed in parallel, and The outflow part of the primary treated water of the treatment tank and the aerobic biological filter apparatus are communicated with each other through a communication passage having a storage tank interposed therebetween.
A flow path for introducing the next treated water to the lower part of the filter bed in the aerobic biological filter apparatus is connected, and the cleaning wastewater of the aerobic biological filter apparatus is guided to the settling section of the treatment tank.

[Work]

According to the present invention having the above-mentioned configuration, SS such as sewage and raw water containing soluble BOD and the like flow from the raw water inflow section into the settling section in the treatment tank, and the settling SS in the raw water precipitates. Thus
The raw water from which most of the SS has been settled and removed is reversed upwards and enters the floating filter material layer in the upper part of the tank in an upward flow, and the fine SS that could not be completely settled is removed by filtration and the air diffuser is used. The dissolved BOD in the raw water is decomposed and removed by the aerobic biofilm developed on the filter medium surface of the floating filter medium layer by the diffusion of the oxygen-containing gas from the.

Then, the primary treated water flowing out from the upper part of the floating filter medium layer is temporarily stored in the storage tank from the floating filter medium layer via the primary treated water outflow part, and then flows into the upper part of the aerobic biological filter apparatus. At the same time, under aerobic conditions, the SS and BOD remaining in a small amount in the primary treated water passed through the filter bed in a downward flow, and were further purified, and the nitrification of NH ₄ -N proceeded sufficiently. , SS,
Purified water of several mg / or less is obtained for both BOD and NH ₄ -N.
Since the primary treated water that flows into the filter bed of this aerobic biological filter equipment has a small amount of SS and BOD, the clogging of the filter bed is extremely slow due to the downward circulating water, and it is very slow. The filter bed does not need to be washed and maintenance is easy.

As the above treatment is continued, the filtration resistance reaches a specified value (about 1 mH ₂ O) due to the increase in the amount of SS accumulated in the flotation filter layer and the growth of biofilm. Wash the layers.

The cleaning method is as follows. That is,
When the amount of air diffused from the air diffuser is rapidly increased while the raw water is flowing in to cause a violent gas-liquid multiphase flow in the floating filter layer, excess SS content in the filter layer is washed out and washed. It is carried along with the drainage and flows out. It is advisable to introduce this SS-containing cleaning wastewater into the sedimentation section at the lower part of the tank again, and if necessary, inject a coagulant or the like to promote the precipitation separation of SS in the precipitation section. The cleaning wastewater from which the SS has been separated can be reused again as cleaning water for the floating filter layer in the upper part. Thus, after the cleaning for the predetermined time, the diffused air amount is returned to the steady state.

Next, the filter bed of the aerobic biological filter equipment, although slow,
Filtration resistance increases. When the filtration resistance reaches the set value,
This filter bed will also be washed. This cleaning method is performed based on the following configuration. That is, the primary treated water outflow portion of the treatment tank and the aerobic biological filter device are connected by a communication passage, and a storage tank is interposed in this communication passage, and the primary treated water of the storage tank is aerobic biological filter bed. A flow path for press-fitting into the lower part of the filter bed inside the equipment will be attached so that the cleaning wastewater of the aerobic biological filter bed equipment will be guided to the sedimentation part of the treatment tank. Therefore, when cleaning the filter bed of the aerobic biological filter apparatus, the primary treated water in the storage tank is press-fitted into the lower part of the filter bed, and the filter bed is backwashed and disturbed for cleaning. At this time, it is not necessary to stop the aeration for keeping the filter bed aerobic. Further, the cleaning wastewater is guided from the upper part of the aerobic biological filter apparatus to the settling section of the previous treatment tank and is reprocessed.

As described above, in the present invention, the cleaning of the floating filter medium tank of the treatment tank and the cleaning of the filter bed of the aerobic biological filter apparatus do not need to waste the clear treated water as in the conventional apparatus, and the treated water does not have to be treated. Production efficiency is high.

Furthermore, preferred processing operations of the present invention are shown.

When removing phosphorus from raw water, inorganic flocculants such as aluminum sulfate, polyaluminum chloride, ferric chloride, and polyiron sulfate are added to the raw water, and the resulting flocs are favorably used as the flotation filter layer of the treatment tank. It is captured by the filter bed of aerial organism filter bed.

If high COD removal is required, raw water or 1
Powdered activated carbon is added to the next treated water, and this powdered activated carbon is captured by the settling section of the treatment tank, the floating filter layer or the filter bed of the aerobic biological filter apparatus.

When removing chromaticity or highly removing BOD (for example, when BOD is 2 mg / mg or less), ozone is diffused from the bottom of the filter bed of the aerobic biological filter equipment. It has been found that this operation can significantly increase the ozone absorption efficiency.

[Embodiment] An embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 1 is a processing tank, and styrene foam, plastic such as polyethylene, wood chips, perlite, pumice stone, hollow glass are provided in an upper portion of the tank. A levitation material layer 2 filled with a levitation material such as a ball or the like having a specific gravity of less than 1.0 is provided, and the upper portion thereof is covered with a water-permeable supporting member 3 such as a net to prevent the levitation material layer 2 from flowing out. However, if the specific gravity of the floating material is close to 1.0, the exposure rate on the water surface is small, so the support member 3 is not necessarily required. Further, an oxygen-containing gas such as air is diffused inside or below the levitation material layer 2 to supply oxygen to the aerobic biofilm that has developed on the material surface, and at the time of cleaning the levitation material layer 2. In order to increase the air volume and promote the cleaning effect, for example, an air diffusing pipe 5 for diffusing air from the blower 4 is provided.

A lower part of the inside of the treatment tank 1 is formed as a settling part 6, and a raw water inflow pipe 9 connected to a raw water tank 7 and having a pump 8 is opened in the settling part 6. In the raw water inflow pipe 9,
A coagulant injection pipe 10 is connected to the suction side or the discharge side of the pump 8 as needed.

An overflow ronder 11 is provided at the upper part of the treatment tank 1 and a primary treated water outflow pipe 12 is connected thereto, while a cleaning drainage outflow pipe 14 having an opening / closing valve 13 is connected thereto, and this cleaning drainage outflow pipe 14 is connected. Is opened to the raw water tank 7.

Reference numeral 15 is a sludge pipe connected to the bottom of the treatment tank 1, 16 is a sedimentation section 6
Shows the settling sludge.

21 is an aerobic biological floor device, anthracite inside,
A floor 22 filled with a granular material having a specific gravity of 1.0 or more such as sand or granular activated carbon is provided, and an exhaust pipe 24 for aeration connected to a blower 23 is provided below the floor 22.

Further, the primary treated water outflow pipe 12 at the upper part of the treatment tank 1 is opened to communicate with the upper portion inside the aerobic biological bed apparatus 21, and the primary treated water flowing through the floor 22 in a downward flow is treated as the final treated water. Turned floor 22
It is designed to flow out from the final treated water outflow pipe 25 connected to the lower part of the. The opening position of the primary treated water outflow pipe 12 in the aerobic biological bed apparatus 21 and the opening position of the final treated water outflow pipe 25 are turned upside down from the illustrated example, and the primary treated water is directed upward on the floor 22. It is also possible to let it flow through and then flow out from the upper part.

Further, in the present invention, a storage tank 31 for temporarily storing the primary treated water flowing into the aerobic biological bed apparatus 21 is interposed in the middle of the primary treated water outflow pipe 12, and the storage tank 31 and the aerobic biological bed apparatus 21 are provided. It is desirable to connect the lower part of the floor 22 with the cleaning water pipe 34 equipped with an on-off valve 32 and a pump 33 so that it is convenient for cleaning the floor 22. It is also preferable to connect the outflow pipe 35 and the raw water tank 7.

In addition, if the storage tank 31 is installed at a high place and the primary treated water in the storage tank 31 is pressed into the lower part of the floor 22 in the aerobic biological bed apparatus 21 due to the water level difference, the pump 33 is omitted. You can

〔The invention's effect〕

As described above, according to the present invention, all the drawbacks of the conventional device are solved and the following remarkable effects are achieved.

Since a treatment tank in which the aerobic floating filter material layer and the precipitation part are integrated is provided in the front stage of the aerobic biological filter device, the SS and BOD flowing into the aerobic biological filter device in the subsequent stage can be remarkably reduced. Clogging becomes extremely slow. As a result, SS, BOD
High purification can be stably obtained even for high-quality raw water.

Since no separate settling tank is required, significant space saving and construction cost reduction can be achieved.

It is not necessary to use the most purified final treated water to wash the filter medium, and extremely efficient washing is possible, resulting in high production efficiency of treated water.

 The cleaning wastewater of the filter bed itself can be reused as cleaning water.

Since the cleaning wastewater can be guided to the settling part of the treatment tank, flowed into the storage tank after processing, and reused as cleaning water as needed, it is possible to reliably eliminate the need to use clean treated water. In addition, it is possible to omit a separate settling basin, and it is possible to easily process the cleaning wastewater with high SS in the processing tank with the settling section.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention. 1 ... Treatment tank, 2 ... Floating material layer, 3 ... Support member, 4,
23 ... Blower, 5,24 ... Air diffuser, 6 ... Settling section, 7 ...
… Raw water tank, 8,33 …… Pump, 9 …… Raw water inflow pipe, 10
…… Coagulant injection pipe, 11 …… Overflow ronder, 12 …… Primary treated water outflow pipe, 13,32 …… Opening / closing valve, 14,35 …… Washing drainage outflow pipe, 15 …… Mudging pipe, 16 …… Settled sludge, 21 …… Aerobic biological bed equipment, 22 …… Bed, 25 …… Final treated water outflow pipe, 31…
… Storage tank, 34… Water pipe for cleaning.

Claims (1)

[Claims] 1. A floatable filter medium layer is held in an upper part of a tank, and an air diffuser is provided inside or below the floatable filter medium layer, and a raw water inflow part is provided in the settling part in the lower part of the tank as a settling part. A treatment tank with a primary treated water outlet at the top of the tank and a specific gravity of 1.0
An aerobic biological filter apparatus provided with a filter bed of the above-mentioned granular filter media is installed in parallel, and the primary treated water outflow portion of the treatment tank and the aerobic biological filter apparatus are connected to each other through a storage tank. And communicate with the flow path for introducing the primary treated water of the storage tank to the lower part of the filter bed in the aerobic biological filter apparatus,
A biological treatment device for organic sewage, characterized in that cleaning wastewater of the aerobic biological filter device is guided to a settling portion of the treatment tank.