JPH0516000Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a purification device for treating gray water, human waste water, etc., and particularly to a small-sized purification device for individual use in general households. [Prior Art] So-called closed water bodies, such as lakes and marshes and inland seas, are rapidly becoming eutrophic due to the influx of various nutrients. Eutrophication is a phenomenon in which the concentration of nutrients such as nitrogen and phosphorus in wastewater increases, and algae and aquatic plants that use this to carry out photosynthesis proliferate abnormally. In particular, when it comes to nitrogen compounds in water, almost everything other than the excrement of aquatic organisms has entered the environment due to human activities, and the influence of gray water and human waste septic tank discharge water is particularly large. Therefore, various household individual purifiers having a denitrification function have been proposed for purifying gray water and human waste water. One example is a method in which nitrification in an aerobic treatment tank is carried out by adjusting the amount of raw water flowing in, the residence time of the aerobic treatment tank, etc., using a so-called volume load adjustment method. [Problems that the invention aims to solve] However, with such a treatment method, the amount of treatment decreases, the treatment capacity does not increase, and if the amount of treatment is increased, the volume of the treatment tank must be increased, making it less compact. It has the disadvantage of being lacking. This invention was devised in view of the above circumstances, and its purpose is to purify domestic wastewater and human waste water used individually in general households.
It is an object of the present invention to provide a purification device which has a compact and simple structure and has an excellent denitrification processing ability. [Means for Solving the Problems] In order to solve the above problems, the present invention provides a purification apparatus having an anaerobic filter bed tank, a biofilm filtration tank filled with a granular porous carrier, and a treated water tank. This system is characterized by being equipped with a treated water return device that returns a portion of the treated water from the aquarium to the biofilm filtration tank and the anaerobic filter bed tank, respectively, for biological nitrification and denitrification. [Function] The purification device of the present invention includes a treated water return device that returns a portion of the treated water in the treated water tank to the biofilm filtration tank and the anaerobic filter bed tank, respectively. By returning to the filter tank and anaerobic filter bed tank,
Biological nitrification and denitrification are carried out. Therefore, the device of the present invention has an extremely excellent processing ability for purifying gray water and human waste water used individually in general households, especially for denitrification, and as a result, the device itself is extremely compact. [Example] An example of the present invention will be described with reference to FIG. FIG. 1 shows a schematic vertical sectional view of the purification apparatus of the present invention. As shown in FIG. 1, the purification device of the present invention has an anaerobic filter bed tank first chamber R1, an anaerobic filter bed tank second chamber R2, a biofilm filtration tank S, and a treated water tank T. . Anaerobic filter bed tank first chamber R1, anaerobic filter bed tank second chamber R2 (hereinafter referred to as filter bed tank R1, filter bed tank R2, respectively)
anaerobic biochemical treatment is usually carried out. Although various configurations can be considered for the configuration of such filter bed tank R1 and filter bed tank R2, the configuration shown in FIG. 1 is particularly preferable among them. That is, as shown in FIG.
and the filter bed tank R2 is the low water level (LWL) of the filter bed tank R1.
Both tanks have filter beds 5a, 5 filled with a filter material that easily retains anaerobic microorganisms and is hard to clog.
b, and spaces are provided below the filter beds 5a and 5b, respectively. The filter bed tank R1 is provided with an inlet 3 through which raw water (sewage) flows, and a water conduit 4 connected to the inlet 3 with openings on the lower side and on the side, and directly below the lower opening of the water conduit 4. A baffle plate (not shown) is provided above the filter bed 5a in order to prevent the water flow from the water conduit 4 from concentrating in one place, but to spread it around and prevent the water in the tank from being agitated. This filter bed 5
a holds anaerobic microorganisms, and filter bed tank R1
constitutes an anaerobic filter bed tank R together with the filter bed tank R2. A cleaning tube 6 is provided which extends vertically downward from the filter bed 5a along a partition wall 7 that partitions the filter bed tank R1 and the filter bed tank R2 and is open there. This cleaning tube 6 is for inserting a nozzle of a cleaning pump (not shown) to the bottom of the cleaning tube 6 during cleaning. In the filter bed tank R2, an intermittent metering pump 9 is installed immediately above the filter bed 5b, and a water inlet 11 of the intermittent metering pump 9 is connected to the filter bed 5 through a one-way valve 10.
It opens downward into the upper surface of b. This intermittent metering pump 9 is operated by a pump blower 16 connected to a pipe 14 via a solenoid valve 15. When the water level in the filter bed tank R2 is lower than the position of the suction pipe horizontal portion 17 (low water level: LWL), water is not sent to the biofilm filtration tank S, which will be described later, and is sent only when the amount is higher than this. Even if the amount of sewage flowing in from the water conduit pipe 4 increases or decreases, the intermittent metering pump 9 prevents it from overflowing, and instead flows through the pipe 13 to the biofilm filtration tank S.
Because the data is sent to , stable processing is possible at all times. Following such a filter bed tank R2, a biofilm filtration tank S
is installed. The biofilm filtration tank S nitrates ammonia nitrogen remaining in wastewater to nitrite nitrogen using nitrite bacteria, and performs microbial treatment using the decomposition action of microorganisms to remove pollution-causing substances and phosphate ions. The purpose is to perform bioadsorption and physical filtration of iron ions, etc., and various configurations can be considered for the treatment tank, but among them, the configuration described below is particularly preferable. That is, a backwash drain pipe 31 is provided above the biofilm filtration tank S, through which treated water that increases and overflows in the biofilm filtration tank S during backwashing is returned to the filter bed tank R1, while near the bottom thereof, a backwash drain pipe 31 is provided. As shown in the figure, an aeration/backwashing pipe 37 connected to an aeration blower 35 is provided in a framed manner, and this framed portion is provided with many holes. Rostles 39 and 41 are provided both above the framework of the aeration/backwashing pipe 37 and near the bottom of the opening of the connecting pipe 13, between which granular porous particles to which aerobic microorganisms are attached are provided. A biofilm filtration layer 45 is formed by filling a large number of carriers 43 made of ceramics. As the granular porous ceramic, for example, highly porous granular foam glass is preferably used. Materials for the highly porous granular foam glass include silica glass, soda coal glass, aluminoborosilicate glass, borosilicate glass, aluminosilicate glass, lead glass, etc., and can be changed as necessary, but economically. Soda-lime glass is desirable because it is inexpensive. In addition, using glass with a special composition impregnated with metals such as iron,
It is also possible to increase the removal rate of specific components such as phosphorus. The foam glass used is granular and highly porous. The particle size of this foam glass is, for example, 0.2 to 20 mm, preferably 4 to 10 mm.
mm. If the upper limit of the particle size is exceeded, the attachment of microorganisms will be concentrated on the surface of the carrier, resulting in poor purification efficiency, whereas if the particle size is less than the lower limit of the particle size, clogging may occur. The porosity of this foam glass is high, specifically a total pore volume of 1 to 4.5 ml/g, preferably 2 to 3.5 ml/g, and a water absorption rate of 50 to 85%, preferably 70 to 85%. (Vol/Vol), median pore diameter (volume) 1 to 50 μm, preferably 5 to 50 μm, bulk specific gravity
It is 0.1-1.5, preferably 0.15-0.4. The above-mentioned highly porous granular foam glass can be produced by, for example, immersing granular foam glass having a water absorption rate of 5 to 20% produced by a conventional method in hot water or an alkaline solution to remove the soluble alkali components in the granular foam glass. This can be produced by removing the granular foam glass and creating openings in the surface layer as well as in the closed cells. It can also be produced by adding 5 to 10% of a metal oxide with a high melting point, such as alumina, silica, zirconia, etc., to glass powder, firing it, and then rapidly cooling it to generate fine bubbles. can do. Porous ceramics made of porous granular foam glass, for example, are porous as described above, so they have a large specific surface area and pore volume, and have an optimal structure for the adhesion and growth of microorganisms. can be maintained. Therefore, when the biofilm filtration tank is constructed of a carrier made of porous ceramics, the processing capacity can be further increased and the tank can be further downsized. In addition, the specific gravity is close to 1, and even a slight flow can change the position and stir it. In other words, the backwashing power may be extremely small. Further, at the bottom of this biofilm filtration tank S, an opening is opened below the rostre 39, that is, below the biofilm filtration layer 45, and the biofilm filtration layer 4
A pipe 47 is provided to supply the treated water purified by step 5 to the treated water tank T, and to send the treated water from the treated water tank T back to the biofilm filtration tank S during backwashing. This pipe 47 connects the biofilm filtration tank S and the treated water tank T. In the treated water tank T, an intermittent metering pump 54 is installed as an example of a treated water return device. A main pipe 57 is provided upward connected to the intermittent metering pump 54, and as shown in the figure, a return pipe 58 is connected to the main pipe 57.
It is branched into a and 58b. The return pipe 58a extends to the biofilm filtration tank S in order to return a portion of the treated water to the biofilm filtration tank S. And that pipe 58a
A flow rate adjustment valve 59a is provided near the tip of the flow rate adjustment valve 59a, so that the amount of return can be adjusted as desired. By the way, the other return pipe 58b extends to the anaerobic filter bed tank R1 in order to return a part of the treated water to the anaerobic filter bed tank R1.
Similarly, a flow rate adjustment valve 59b is provided at the tip of b. Another example of a treated water return device is the so-called air lift system, in which the height of the weir is adjusted to adjust the flow rate of the treated water returned. . The reason why a portion of the treated water in the treated water tank T is returned to the biofilm filtration tank S and the anaerobic filter bed tank R1 will be explained. The reason why a portion of the treated water in the treated water tank T is returned to the biofilm filtration tank S is to completely nitrify the ammonia nitrogen remaining in the treated water to nitrite and nitrate nitrogen. In other words, by returning a portion of the treated water to the biofilm filtration tank S, dissolved oxygen (DO) in the upper layer of the biofilm filtration tank S is increased and biochemical oxygen demand (BOD) is lowered. In addition, the amount of water passing through the biofilm filtration tank S increases, and as a result, the raw water is evenly distributed throughout the biofilm filtration tank S, which reduces the activity of nitrite bacteria and nitrate bacteria. can oxidize ammonia to nitrite and nitrate ions. In this case, the circulation ratio, that is, the ratio r1 of the amount of returned water to the biofilm filtration tank S to the amount of raw water inflow, is 0.5 to
4.0, especially 2.0-3.0 is preferred. If this value is less than 0.5, the nitrification rate of the treated water will be poor, while if this value exceeds 4.0, it will cause unnecessary circulation, which is not preferable. On the other hand, the reason why a part of the treated water in the treated water tank T is returned to the anaerobic filter bed tank R1 is to denitrify the treated water that has been decomposed into nitrite ions and nitrate ions as described above. . That is, oxygen in nitrite ions and nitrate ions of the treated water returned to the anaerobic filter bed tank R1 is removed by denitrifying bacteria that breed in the anaerobic filter bed tank R1,
Due to this reduction action, nitrogen in nitrite ions and nitrate ions is released into the atmosphere as N ₂ gas, and inorganic nitrogen in the wastewater is removed. In this case, the circulation ratio, that is, the ratio r2 of the amount of returned water to the anaerobic filter bed tank R1 to the amount of raw water inflow, is 0.5
-6.0, especially 3.0-4.0 are preferred. If this value is less than 0.5, the nitrogen removal rate of the treated water will be slightly poor, while if this value exceeds 6.0, unnecessary circulation will be required, which is not preferable. In this way, by returning a portion of the treated water in the treated water tank T to the biofilm filtration tank S and the anaerobic filter bed tank R1, respectively, nitrite ionization and nitrate ionization of ammonia, and oxidized nitrogen Denitrification in the compound takes place. As an example of a specific operation, first, the intermittent metering pump 54 is operated, and a part of the treated water in the treated water tank T is returned to the biofilm filtration tank S via the return pipe 58a, and then the treated water is returned to the biofilm filtration tank S and treated. The ammonia in the treated water is forced to circulate between the water tanks T to ionize nitrite and nitrate, and then the ionized treated water is sent to the anaerobic filter bed tank R1 via the return pipe 58b.
The entire septic tank is brought into continuous operation by starting to return the water to the tank. In addition, the other end of the pipe 47 extends to the bottom of the treated water tank T, and a backwash pump 53 is usually attached to which the treated water is sent back. Further, an elbow pipe 55 is provided at an intermediate position of the pipe 47, and discharges the treated water treated in the biofilm filtration tank S to the treated water tank T. In order to overflow and discharge this treated water, usually a small chamber 57, as shown in the figure,
59 and 61 are provided, and water is discharged from a discharge port 63 provided in the small chamber 61. A cartridge 65 is usually provided in either of the small chambers 59, 61 to neutralize, sterilize, etc. the treated water that has been treated with organic substances. In the purification device of the present invention described above, each tank (anaerobic filter bed tank first chamber R1, anaerobic filter bed tank second chamber R2, treated water tank T, etc.) is manufactured individually, and these are connected by piping. However, usually, each tank is integrally molded from a material such as reinforced fiber plastic (FRP), and predetermined filter beds 5a, 5b, piping, pumps, etc. are built into these to provide predetermined functions. It is preferable to make the purification device more compact. Next, a method for treating wastewater using the purification device 1 described above will be explained. The purpose of the purification device 1 of the present invention is to purify domestic wastewater and human waste that are used individually in general households, and therefore, the size of each tank of the purification device should be adjusted accordingly. be discovered. The sewage first passes through the water conduit 4 from the first inlet 3, is spread by a baffle plate (not shown), is spread on the filter bed 5a, and is sent to the filter bed tank R1 of the raw water tank R. When the water level rises and the raw water reaches the middle of the water pipe 4, it flows out from the side opening 8. When wastewater passes through the filter bed 5a, anaerobic microorganisms are attached to the filter bed 5a, and primary decomposition and adsorption of organic matter takes place here. The water that has passed is filtered into the filter bed tank R.
As the water level of 1 is raised, organic matter is similarly decomposed and adsorbed in the filter bed 5b. Water level is horizontal part 1 of suction pipe
After the pressure exceeds 7, the solenoid valve 15 is opened, and the pressure of the pump blower 16 operates the intermittent metering pump 9 through the pipe 14. This intermittent metering pump 9
By this, a fixed amount of wastewater is sent to the biofilm filtration tank S regardless of the amount of wastewater flowing in. Therefore, when the inflow is large, the water level in the filter bed tank R1 rises within the high water level (HWL) line. The water sent through the pipe 13 enters the biofilm filtration tank S and passes through the biofilm filtration layer 45 in a downward flow. As described above, this biofilm filtration layer 45 is filled with a large number of carriers 43 made of granular porous ceramics, and the carriers 43 descend while bending through the carriers. By the way, at this time, the aeration blower 35 is activated, and the aeration/backwash pipe 37 framed at the bottom is activated.
Air bubbles are blown out and rise. Since the bubbles rise in a curved manner while colliding with the carrier 43, the bubbles do not become coarse rapidly and the residence time becomes long, and a high oxygen utilization rate is obtained, so that high-load operation is possible. In this way, by bringing the raw water into countercurrent contact with the air in the biofilm filtration tank 45, contact aeration is performed, oxygen is dissolved in the wastewater, and the biological oxidation function is enhanced to decompose organic matter and grow microorganisms. Through the filtration effect between the carrier particles and adsorption on the wide biofilm surface, the treated water is purified more efficiently. Note that, as will be described later, the biofilm filtration layer 45 is backwashed every predetermined time period, so there is almost no precipitation at the bottom. The treated water is sent to the treated water tank T through the pipe 47 from the opening of the elbow pipe 55. A part of the treated water in the treated water tank T is circulated in a constant amount to the biofilm filtration tank S via the return pipe 58a by the intermittent metering pump 54, and untreated ammonia nitrogen is completely converted to nitrite and nitrate nitrogen. and is oxidized. The details are as described above. Similarly, a certain amount of the treated water in the treated water tank T is returned to the first anaerobic filter bed tank R1 by the intermittent metering pump 54 via the return pipe 58b.
Here, denitrification of the treated water, which has been decomposed into nitrite ions and nitrate ions, is performed. Note that the details are as described above. By the way, most of the treated water in the treated water tank T is usually stored in connected small chambers 57, 59, 6.
1 and is discharged from the discharge port 63. During this time, the treated water that overflowed from the small chamber 57 was poured into the cartridge 65.
It is neutralized and sterilized by the injection of chemicals, and then released. The processing speed of this discharge is set by supplying water received by the anaerobic filter bed tank R by the intermittent metering pump 9, and this setting is normally set for the biofilm filtration layer 45 of the biofilm filtration tank S. It is set according to processing capacity. Therefore, stable quality of treated water can always be ensured. As a result of sewage treatment, organic matter and proliferated sludge have adhered to the carrier 43 of the biofilm filtration layer 45, and when the backwash pump 53 is activated before this comes off the carrier 43 and begins to settle, the inside of the treated water tank T is removed. The treated water collected in pipe 4
7 and blows up from the bottom of the biofilm filtration tank S into the biofilm filtration layer 45. At this time, elbow pipe 5
Some of it also blows out from 5, but the diameter is small so it's not a problem. Due to this upward flow, the grown sludge and the like that are attached and trapped in the biofilm filtration layer 45 are removed by the aeration blower 3.
Together with the air bubbles blown out from the air bubbles 5 through the aeration/backwash pipe 37, the air bubbles are removed and floated in the backwash wastewater. Here, the biofilm filtration layer 45 is a multi-carrier 43 of granular porous ceramics, as described above,
Since the specific gravity is close to 1, the carriers 43 fly up and collide with each other, causing the trapped grown sludge to be released and washed. As the treated water from the treated water tank T is sent in by the backwash pump 53, the water level in the biofilm filtration tank S rises, and together with the floating proliferated sludge, the water is sent to the filter bed by the upper backwash drain pipe 31 as backwash wastewater. It is returned to tank R1. This backwash wastewater passes through the filter beds 5a and 5b and is decomposed by anaerobic microorganisms again, reducing the grown sludge to float or settle at the bottom of the anaerobic filter bed tank R. This backwashing is performed every predetermined period of time to wash the biofilm filtration layer 45, restore the decomposition and adsorption capacity, and return the grown sludge etc. to the anaerobic filter bed tank R.
A nozzle of a cleaning pump is inserted into the cleaning tube 6 of the cleaning tube 6, and the grown sludge is periodically extracted and treated. This type of backwashing method does not particularly reduce the processing capacity of the biofilm filtration layer and does not require a settling tank.
This is ideal for maintaining processing capacity that does not change much at all times. After this backwashing is completed, the wastewater continues to flow into the anaerobic filter bed tank R, and normal purification processing is performed. When treating domestic gray water, it is sufficient to carry out such backwashing once a day, for example. In the embodiment of the present invention, the pump, which is an example of a treated water return device, is installed in the treated water tank T, but the pump is not limited to this, and can be used to transport some of the treated water in the treated water tank T. They may be installed anywhere as long as they can be returned to the biofilm filtration tank S and the anaerobic filter bed tank R1, respectively. Further, the number of treated water return devices is not limited to one, and two devices may be provided, one for returning to the biofilm filtration tank S and the other for returning to the biofilm filtration tank S. Further, in the embodiment of the present invention, a part of the treated water is returned to the anaerobic filter bed tank R1, but it goes without saying that it may be returned to the anaerobic filter bed tank R2. Also,
It may be returned to both anaerobic filter beds R1 and R2. Next, a specific purification experiment was conducted using the apparatus shown in FIG. Experimental Example 1 First, in order to investigate the change in nitrification rate due to circulation between the treated water tank T and the biofilm filtration tank S, the following experiment was conducted. That is, first, raw water is introduced through the inlet 3 and subjected to normal purification treatment, and then the pump 54, which is the treated water return device, is operated to send a certain amount of treated water only to the biofilm filtration tank S ( return) and
Purification treatment was carried out while circulating between the treated water tank T and the biofilm filtration tank S. In this case, the circulation rate was varied. The results are shown in Table 1 below.

[Table] In Table 1, the circulation ratio r1 represents the ratio of the amount of raw water returned to the biofilm filtration tank to the amount of raw water inflow. Raw water TN and treated water TN indicate the total nitrogen content in raw water and treated water, respectively. Treated water NOx _- N indicates the total nitrogen content in nitrogen oxides. Experimental example 2 Circulation ratio r1 = 2 where the optimal effect was obtained in experimental example 1
was left as it was, and the treated water in the treated water was returned to the anaerobic filter bed tank R1. In this case as well, the amount of return (circulation ratio r2) was varied. The results are shown in Table 2 below.

[Effect of idea]

From the above results, the effects of the present invention are clear. That is, the purification device of the present invention is equipped with a treated water return device that returns a portion of the treated water from the treated water tank to the biofilm filtration tank and the anaerobic filter bed tank. Nitrification and denitrification are performed by returning the water to the anaerobic filter bed tank.
Therefore, the treatment capacity for purifying gray water and human waste water used individually in general households, especially for denitrification, is extremely excellent, and as a result, the apparatus itself is extremely compact.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of the purification device of the present invention. R1...Anaerobic filter bed tank 1st chamber, R2...Anaerobic filter bed tank 2nd chamber, S...Biofilm filtration tank, T...Treatment water tank, 5a, 5b...Filter bed, 39,41... ...Rostol, 43...Carrier, 45...Biofilm filtration layer, 5
4...Intermittent metering pump.

Claims (1)

[Scope of Claim for Utility Model Registration] A purification device having an anaerobic filter bed tank, a biofilm filtration tank filled with a granular porous carrier, and a treated water tank, A process in which a portion of the treated water in the treated water tank that has been sequentially processed through the filtration tank and treated water tank is returned to the biofilm filtration tank and the anaerobic filter bed tank for biological nitrification and denitrification. Equipped with a water return device, the ratio of the amount returned to the biofilm filtration tank to the amount of raw water inflow in the treated water return device is 0.5 to 4.0, and the ratio of the amount returned to the anaerobic filter bed tank to the amount of raw water inflow is:
A purification device characterized in that it is 0.5 to 6.0.