JPS6150695A - Multistage waste water treatment apparatus by digestive bacteria - Google Patents

Abstract

PURPOSE:To efficiently reduce BOD and COD in waste water, by connecting treatment tanks each equipped with a digestion chamber and a sedimentation chamber between a raw waste water introducing side and a final treated waste water side along a flow passage direction successively in series in a multistage fashion. CONSTITUTION:The concn. of waste water is lowered to about 50ppm in the digestion chamber of a treatment tank 1B and the waste water from this treatment tank 1B is withdrawn by a pipe 10 as the supernatant solution of a sedimentation chamber 4 to be introduced into the digestion chamber 3 of a final third stage treatment tank C. In this digestion chamber 3, final treatment is performed by bacteria grown and propagated under the nutritive condition of this introduced waste water in the same way as treatment tanks 1A, 1B and, as a result, the aforementioned BOD concn. of 50ppm is reduced to about 5ppm and waste water is withdrawn from the upper part of the sedimentation chamber 4 by a pipe 11 to be discharged to the outside of the apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to wastewater treatment equipment, and particularly to BOD. C.O.
The present invention relates to a multistage wastewater treatment device that reduces D, SS, etc. by the digestive decomposition activity of bacteria.

(Description of Prior Art) A treatment method in which wastewater containing various components is digested and decomposed by the activity of microorganisms is widely known and put into practical use, for example, the activated sludge method. However, the activated sludge method poses problems in the secondary treatment of a large amount of digested sludge consisting of microbial residue and untreated solids produced as a result of the treatment, and the need to constantly maintain optimal conditions for bacterial growth and reproduction. requires maintenance and management.

(Object of the Invention) The object of the present invention is to eliminate the drawbacks of the conventional wastewater treatment equipment, effectively treat wastewater containing various components without producing treatment residue, and reduce BoD, COD, and s in the wastewater.
An object of the present invention is to provide a wastewater treatment device that can effectively reduce s, etc., and has extremely simple equipment and maintenance management.

(Structure of the Invention) The object of the present invention is to provide a digestion chamber in which introduced water to be treated is stirred together with wood chips as a treatment medium, digested and decomposed by digestive bacteria, and then drained out. It consists of a plurality of treatment tanks each having a sedimentation chamber installed above the digestion chamber in communication with the digestion chamber and configured to allow the supernatant water after the sedimentation treatment to flow out. This is achieved by a multistage wastewater treatment device using digestive bacteria that are connected in series in multiple stages along the flow path direction between the outflow sides of the final treated wastewater.

In recent years, as improvements to the activated sludge method, the fluidized bed method and biofilm V, which use a treatment medium made of inorganic particles and attach microorganisms to these media, have been introduced. Some proposals have been made to use organic materials such as sawdust as the treatment medium (Japanese Patent Laid-Open No. 52-138382.52-30058゜54-98).
No. 047, etc.).

However, these conventional techniques use sawdust obtained during sawmilling either as it is or after delignifying it based on knowledge in the fields of deodorization and adsorption, and in both cases, it is not suitable for wastewater treatment. It shows no effect. Moreover, when these sawdust are actually used, they become extremely clogged and have a high degree of wear and tear. In addition, in the case of delignified sawdust, there are problems in terms of processing costs, etc. However, it has not been put into practical use yet.

According to the results of experiments and research conducted by the present inventors to date, the use of wood chips that have been subjected to specific physical treatments during wastewater treatment has been shown to reduce the effects of various soluble organic substances and insoluble suspended solids. It was unexpectedly discovered that wastewater with high levels of BOD, COD and SSs can be treated very quickly to acceptable concentration levels without any residue remaining after the treatment medium.

The wood chips used in the present invention are obtained by crushing logs of a certain material, vigorously stirring them in water to grind them together, and removing at least part of the particles with a particle size of 150 microns or less from the resulting chips. It is obtained by a purely physical process of cleaning and removing it.

Wood chips obtained through such simple treatment have extremely good wastewater treatment effects, and are far superior in terms of practical use compared to the conventional untreated or delignified sawdust. .

First of all, the wood chips basically have good moisture retention and heat retention properties like ordinary sawdust, and have an extremely large surface area due to the complex three-dimensional structure of cellulose, which is the main component of wood, and are useful for wastewater treatment. Suitable as a waxy material for bacterial growth.

In particular, in the wood chips of the present invention, fine powder with a particle size of about 150 microns or less is at least partially removed by the above-mentioned stirring, grinding, and washing, so that the structure of the chips becomes more irregular and becomes a site for microbial breeding. As a result, the surface area increases significantly. In addition, it is assumed that the fine powder removed here would gradually fall off the surface of conventional untreated sawdust during use, causing clogging of the fine channels in the medium. .

In addition, wood cellulose is only attacked by some molds that exist extremely rarely, so it has the property of not decomposing for a long time, but the lignin component present on its surface contributes to its stability. It is thought that there are. Therefore, avoiding delignification by alkaline treatment, etc. will maintain the original stability of wood cellulose, and will also reduce the adsorption of various metals and salts due to the metal substitution ability of the functional groups of lignic acid. It is also thought to be effective in treating wastewater containing components. As a result of the treatment described above, the wood chips used in the present invention exhibit surprising effectiveness as a wastewater treatment medium. In general, bacteria have unique conditions that are optimal for their growth and reproduction depending on their type, and therefore
It is widely known that when conditions such as nutrients, temperature, and inhibitors change, bacteria that are adapted to these conditions develop and proliferate. In such a case, the wood thin J1 used in the present invention
1) Alternation of bacteria that occurs in response to changes in the conditions described in II.
Provide an extremely suitable environment for issuing Y letters. That is, cellulose, which is the main component of wood, basically has excellent characteristics not found in inorganic media due to its good moisture retention, heat retention, and large surface area. In particular, since the wood chips used in the present invention have not been subjected to any chemical treatment such as delignification, the original organic living tissue of the wood is retained as is. Therefore, in terms of pH stability and buffering properties against inhibitors and other components, wood chips integrate highly complex functions such as substitution, adsorption, and ion exchange, just like humus in natural soil. form a stable living environment for the bacteria that harbor it.

As a basic experiment, the present inventors put 11 people in a medium-sized treatment tank filled with the above-mentioned wood chips and subjected them to haunch treatment. In addition, no treatment residue was observed in the treatment tank.In this case, the tank was not equipped with any active aeration stage other than air flowing naturally from the surface. Therefore, the microorganisms (bacteria) involved in wastewater treatment are at least different from those in the conventional active mixed method. , and the type of α1 body that is generated changes with the passage of time between treatments ++ and ν.The striation 1 in the tank changes due to the digestive decomposition products generated as the relatively large bacilli that are noticeable at the beginning digest the wastewater. However, under these changed conditions, cocci that feed on the digestive decomposition products and bacterial cell residue (or bacterial cells themselves) were found to generate and grow instead.

Based on the experimental results, the inventors of the present invention have found that (if a plurality of treatment tanks are provided and connected in sequence, bacterial cells will be generated whose growth conditions are the same as those found in each tank). We assumed that this would make the treatment even faster and more effective, so we constructed a system of such series-connected treatment tanks to continuously treat wastewater.The results were almost as expected. The ppm of the discharged liquid from the tank decreases from the -L flow tank to the downstream tank, and in one example described below, which has a three-stage tank configuration,
The concentration of wastewater of pp+m was reduced to Spp, and 99.5% of the total BOD and COD in the wastewater could be removed by continuous treatment. Moreover, no residual liquid was observed in each treatment tank as a result of the treatment, and the wood chips used as the treatment medium were hardly consumed even during long-time operation. Furthermore, the amount of air used for stirring the treatment tank in the above experiment was significantly reduced compared to the amount of air required in the activated sludge method conducted under the same conditions for comparison. Furthermore, even if stirring is stopped for a long time during treatment, phenomena such as bulking and rancidity in the treatment tank, which are observed in conventional activated sludge methods, are not observed at all, and the maintenance and management of the equipment is extremely easy.

EXAMPLES Below, more specific configurations, functions, and effects of the present invention will be described based on an example of the present invention in which each treatment tank is connected in series in three stages and applied to continuous treatment of wastewater from a seafood factory. 3'
I will explain in detail.

FIGS. 1 and 2 are explanatory diagrams showing longitudinal sections of the first and second stage treatment tanks of the apparatus according to the embodiment of the present invention, and l-11 and II in FIG. -II
It is a large indication along m.

The treatment tank IA of the first stage 11 of this three-stage wastewater treatment apparatus 1 has a digestion chamber 3 and a sedimentation chamber 4 separated from each other by 41 cut plates 8 inside a tank wall 2. The inside of the digestion chamber 3 is filled with wood chips 7 obtained by a process described below. A vibrator 5 for introducing raw water is connected to one part of the digestion chamber 3, and an air supply pipe 6 is installed at the bottom for introducing air as the first stage of stirring in the tank. It is.

A sedimentation chamber 4 is provided on one side of the digestion chamber 3, which is separated from it by a partition plate 8.
Let's communicate with each other. The +-'N5 wastewater obtained by sedimentation is drawn out from one part of the settling chamber 4 and supplied to the second stage shown in FIG. 10 is connected.

The second-stage processing tank IB shown in the second diagram and the third-stage processing tank IC connected downstream thereof are basically formed in the same manner as the first-stage processing tank IA. -F section of the sedimentation chamber 4 of the third stage treatment tank IC.

A pipe 11 is connected to the pipe 11 for drawing out the clear liquid as the final treated wastewater to the outside of the apparatus.

As shown in Figure 3, the treatment tanks IA to IC in the first to third stages of I-L have a flow path from the raw wastewater introduction side (pipe 5) to the final treated wastewater discharge side (pipe 11). are connected in series in order along the In the figure, reference numeral 13 indicates an aeration pipe connected to the air supply pipe 6 and installed at the bottom of each type, and the air supplied from the air supply main pipe 14 is adjusted by each flow valve 12. The air is ejected into each tank from an air diffuser hole (not shown). Among other items, 16 is a fixing member for the partition plate 8. Each treatment tank IA-IC has a capacity of approximately 12 tons, and each type of digestion chamber 3 has a capacity of approximately 3 tons of the tank capacity.
Filled with 5% wood chips.

The wood chips used in this example were obtained by pulverizing cedar wood of a certain material to the particle size distribution shown in column A of the table below, vigorously stirring it in water, grinding it together, and washing it to remove the resulting fine powder. The particle size distribution is shown in Table BJIA.

Particle Size Distribution of Wooden Chips Wastewater with a concentration of 1000 ppm from the Kamapoko food processing factory was continuously injected into the three-stage wastewater treatment equipment at a flow rate of 100 min/min. In order to stir the wastewater together with the wood chips in the digestion chamber 3 of each treatment tank, the coolant flow valve 12 provided in each air pipe 6 is adjusted and the wastewater is transferred to the first, second, and third stage treatment tanks IA to IC. Air was supplied at a rate of 1 m, 0.5 m and 0.2 m per minute, respectively.

The raw water injected from the pipe 5 into the digestion chamber 3 of the first-stage treatment tank IA is circulated in the digestion chamber 3 together with the wood particles 7 by the air ejected from the aeration hole of the aeration pipe 13 at the bottom. Stirred. In this state, fungal cells that use pollutants at a concentration of 1000 ppm in the raw water as nutrients are generated on the surface and within the pores of the wood chips, digesting and decomposing the substances, and reducing the
Reduce the concentration to between 00 PP. The treated wood then enters the sedimentation chamber 4 provided in a part of the digestion chamber 3 through the communication port 9 at the bottom of the partition plate 8 by the injection pressure of raw water. Here, some of the pollutants brought in from the digestion chamber 3 are settled when the waste water rises in the settling chamber 4, and are returned to the digestion chamber 3 along the slope of the partition plate 8, etc. The -I-Wi liquid in the sedimentation chamber 4 after the sedimentation treatment is drawn out through the pipe 10 (FIG. 3) and injected from a part of the digestion chamber 3 of the second stage treatment tank IB in FIG.

In the digestion chamber 3 of the treatment tank IH, bacteria that use the digestion and decomposition products and bacterial cell residue produced in the treatment tank IA as nutrients are generated on the wood chips 7, and are digested and decomposed in the same manner as in the treatment tank IA. Then, the concentration of waste water of 300 pp■ was reduced to about 50%.
Reduce between PP.

The waste water from the treatment tank IB is drawn out through the pipe 10 as -L clear liquid in the sedimentation chamber 4, and is transferred to the final third stage treatment tank 1.
It is introduced into the digestion chamber 3 of c. In this digestion chamber 3, the final treatment is carried out by bacteria that grow and reproduce depending on the nutritional conditions contained in the introduced wastewater in the same way as in the treatment tanks IA and IB, and as a result, the BOD of 50 TIPII is
The concentration is reduced to about 5 ppm, and the captured water is drawn out from the -L section of the settling chamber 4 through the pipe 11 and discharged to the outside of the apparatus. In this treatment tank tC, the air supply amount is 0 as described above.
．． Since the amount of water supplied is extremely small (2 ta" 7 minutes) and is only for stirring inside the tank, and the tank generates significant carbon dioxide and methane gas, the treatment there is not so-called aerobic treatment but rather anaerobic treatment. It can be seen that this is due to processing by bacterial cells that are spread out on the sides.

In this way, in this example, the pollutant temperature is about 1000
PPM wastewater can be continuously treated to reduce the BOD concentration to approximately SPP- (SS was almost O), and each treatment tank contains no excess sludge from the normal activated sludge method. It did not occur.

Furthermore, in this example, the amount of supplied air was reduced compared to when the same raw water was treated to the same concentration using the normal activated sludge method, but this was because the supplied air was This is due to the fact that it is mostly used for stirring rather than for storage, indicating that the apparatus of the present invention performs a treatment using bacterial cells that is different from the usual activated sludge method.

In addition, in normal aeration treatment, if the air supply is not maintained at all times, the activated sludge in the tank will undergo bulking and rancidity, making subsequent use difficult, but with the device of this example, it is possible to agitate for long periods of time, such as at night or on holidays. Even when the process was interrupted, no such inconvenience occurred, and the digestion function was immediately restored each time work was resumed. As described above, the apparatus of the present invention is significantly easier to maintain and manage than conventional aeration tanks. Furthermore, since the operation of the wastewater treatment equipment can be interrupted arbitrarily in accordance with the operation of the -L field, the amount of air blown acid itself is small, and the operating cost of the tank (power consumption of the air blower motor + 8 gold) is kept under the same conditions. compared to the case of an aeration tank.

In this example, there is no need to particularly adjust the growth temperature of the bacteria in the treatment tank, and the bacteria retained on the wood chips can continue the treatment even under winter conditions using only their own oxidative heat generation. be.

When the apparatus of the present invention was applied to the continuous treatment of various other industrial wastewater and livestock manure (mainly urine water) wastewater, excellent results were obtained as shown in the table below.

* Dilute raw water (1800Dpp■) 10 times with wood *
*Average 10 hours of operation per day. All of the above treatments are average values for two years of operation, during which time the required replenishment amount of wood chips was only 3 to 4% per year.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams showing longitudinal sections of an embodiment of the present invention, respectively, and FIG. 3 is a top view of the embodiment. ■01. Three-stage wastewater treatment equipment 1A, 1B, IC, , treatment tank 310. Digestion chamber 408. Sedimentation chamber 511. Vibrator 700. Wooden strips 819. Partition plate 10.11. , , pipe 12. ,,flow valve+
3. ,, Diffusion tube patent applicant Michito Matsuoka Minoru Takayasu Figure 1 Figure 2

Claims (3)

[Claims] (1) A digestion chamber configured to agitate the introduced water to be treated together with wood chips as a treatment medium, digest and decompose the water with digestive bacteria, and then drain the water out, and the upper part of the digestion chamber communicates with this. It consists of a plurality of treatment tanks, each of which is equipped with a settling chamber, which is provided with a sedimentation chamber and is configured to drain out the supernatant water after the sedimentation treatment, and the treatment tank is located between the inlet side of raw wastewater and the outflow side of final treated wastewater. A multi-stage wastewater treatment device using digestive bacteria, characterized in that the multi-stages are successively connected in series along the flow path direction. (2) The wood chips used as the treatment medium are obtained by crushing raw wood materials of a certain material, stirring them in water and grinding them together, and then producing particles with a diameter of about 150 microns or less. A multistage wastewater treatment device using digestive bacteria according to claim 1, which is obtained by at least partially washing and removing particles. (3) The agitation inside the digestion chamber of the processing tank is performed by introducing air into the chamber, and the amount of air supplied is gradually reduced from the upstream processing tank to the downstream processing tank. A multistage wastewater treatment device using digestive bacteria according to claim 1.