JPH01218691A - Method for purifying treatment of organic waste water - Google Patents

Abstract

PURPOSE:To purify waste water with high efficiency, by performing purifying treatment under the repetition of an aerobic state and an anaerobic state while a purifying material is fluidized. CONSTITUTION:A purifying tank 1 having a granular purifying material 19 charged therein is filled with org. waste water and compressed air is blown into the purifying tank 1 from an air diffusing cylinder 26 to stir waste water. Thereafter, aeration is stopped and, after an anaerobic state is held for a definite time, aeration is further performed to fluidize a purifying material. Subsequently, aeration is stopped after a definite time and raw water is replenished immediately after stoppage and the discharge of treated water is performed therewith. Since sludge 18 is accumulated on the bottom part 32 of the purifying tank 1 by repeating these operations, said sludge 18 is taken out by a discharge pipe 36. By this method, high purifying capacity can be kept.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for purifying organic wastewater such as livestock @ sewage, miscellaneous wastewater, and sewage.

[Prior art] Conventionally, there has been a method of quantification of organic wastewater using the immersion method. In this method, a solid filter medium (purifying material) is immersed in the center of the tank, and the surface or voids between the solids are removed. Purification was performed by generating a biofilm on the wastewater and bringing the biofilm into contact with the wastewater. The immersed filter bed method includes a fixed bed method in which the filter bed is densely packed with purifying material, and a method in which a granular filter with small particle size and easy to float is used to fill the filter bed with air or oxygen. There is a method using a fluidized bed in which the purifying material is fluidized by aeration.

On the other hand, there is a biological nitrification/denitrification method as a method for removing nitrogen contained in organic wastewater. There are nitrification/denitrification methods and intermittent nitrification/denitrification methods. In this circulating nitrification/denitrification method, the denitrification rate □ is determined by the amount of circulation, so a large amount of circulating water is required to obtain a high quality treated water for wastewater containing high temperature nitrogen. In such cases, similar effects can be obtained by intermittently bringing the inside of the tank into an aerobic or anaerobic state.

Methods for removing phosphorus include the coagulation-precipitation method and the crystallization dephosphorization method, but the present inventors proposed a method for removing phosphorus using porous calcium silicate (Japanese Patent Application Laid-Open No. 62-18389
(See Publication No. 8).

[Problem to be solved by the invention] However, what about the fluidized bed in the immersion bed method? There is a problem in that a purifying material having a high specific surface area and easily floating must be used, resulting in a low purifying ability. In addition, in the intermittent nitrification/denitrification method, the pH must be adjusted in an aerobic state, and furthermore, it must be quickly changed from an aerobic state to an anaerobic state, making operation and maintenance difficult. There was a point. In addition, when processing in a packed column using porous calcium silicate as a dephosphorizing agent, the specific surface area of the dephosphorizing material cannot be increased due to blockages, etc. In other words, the particle size cannot be reduced, so the purifying ability is suppressed. Is there a problem?

As mentioned above, all conventional purification methods have advantages and disadvantages. Even if the 9-ionization treatment method was adopted, it was not possible to realize a method that combines all the advantages of a combustible purification device, which is easy to maintain and manage, and has high purification ability. An object of the present invention is to provide a method for efficiently purifying organic wastewater containing nitrogen and phosphorus using a compact and easy-to-maintain device.

[Means for Solving the Problems] In order to solve the above problems, the present invention employs the following configuration. That is, the present invention provides a method for preventing organic wastewater from coming into contact with the biofilm that has adhered to the purification material described above in a tank containing a purification material containing porous granular calcium silicate hydrate as a main component. In the method of carrying out purification treatment from water, the purification treatment is carried out under repeated aerobic conditions and anaerobic conditions, and in the aerobic condition, the purification material is flowed, and further, the organic wastewater is supplied to the tank. The gist of this paper is a method for purifying organic wastewater, which is characterized by being carried out under substantially anaerobic conditions.

Here, as the porous granular calcium silicate hydrate,
For example, one or more of tobermorite, xonotlite, C3H gel, phosagite, gyrolite, or hireplandite can be used as a component, and these porous granular calcium silicate hydrates have high purification ability and are suitable.

Further, it is preferable that the porous granular calcium silicate hydrate has a porosity in the range of 60 to 85% because it has high purification ability and is excellent in strength during use.

Furthermore, by carrying out the initialization treatment when the amount of porous granular calcium silicate hydrate packed in the tank is 50% or less by volume, the efficiency of the layer competition can be increased.

[Function] By heating organic wastewater in a tank containing a purification material mainly composed of porous granular calcium silicate hydrate, sufficient oxygen is supplied to the tank and aerobic bacteria are activated. Maintain suitable aerobic conditions. In this aerobic state, organic matter is decomposed by the biofilm deposited on the purification material, and dephosphorization and nitrification are performed.

On the other hand, by stopping aeration, the oxygen in the tank is reduced to maintain a suitable anaerobic state, and denitrification is performed by denitrifying bacteria. Also, by stopping the aeration)
By making the purification material non-fluid, the sludge is quickly settled. In this way, by repeating an aerobic state and an anaerobic state, and then repeating a fluid state and a non-fluid state as the aerobic state is repeated, the environment can be polluted sequentially according to each state within one tank. remove substances that cause

In addition, by supplying the organic wastewater in an anaerobic state, the OD source necessary for denitrification is replenished, and the DO in the water is quickly reduced to enhance the denitrification effect. Also, since it does not interfere with the purification activity of bacteria in an aerobic state, the purification ability is always maintained at a high level.

Due to the above-described effects, the purification/treatment method of the present invention can efficiently purify organic wastewater containing nitrogen and phosphorus with a compact and easy-to-maintain device.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a purification species 1 used in the purification method of this embodiment. The purifying seed 1 is made by joining one end of a cylindrical member 4 and the wide mouth part of a funnel-shaped member 6.

At the top of the septic tank 1, there are provided a supply pipe 10 for sending organic wastewater to the septic tank 1, and a discharge pipe 12 for taking out the purified treated water.

Around the supply pipe 10 placed in the septic tank 1,
The first separation wall 1 is installed to prevent high concentration organic wastewater from directly flowing into the center of the septic tank 1 and causing a sudden change in the purification state.
4? It is provided near the bottom of the septic tank 1. In order to create a one-way flow = 7- in the septic tank 1, a second separation wall 16 and a third separation wall 17 are provided on the center side of the septic tank 1 in parallel with the first separation wall 14. There is. Note that a gap 20 is provided at the lower end of the second separation wall 16 to allow the settled sludge 18 and granular cleaning material 19 to pass through. In addition, a fourth separation wall 24 is provided around the outlet 22 provided at the top of the septic tank 1 to collect the rising liquid to prevent floating matter from the water surface from getting mixed in. .

On the other hand, said? Is there air at the bottom of septic tank 1? A diffuser pipe 26 that blows air into the septic tank 1 is provided, and this diffuser pipe 2
The air pump 301 is connected via an air pipe 28. A discharge pipe 36 connected to a discharge pump 34 for pumping out the sludge 18 is provided at the bottom 32 of the purification type 1.

Inside the septic tank 1, a particle size of 3 m containing tobermorite, a calcium silicate hydrate, as a main component is used as a purification material.
Porous granular cleaning material 1 with an IT of 1 or less and a porosity of 75%
9, 2,50, which corresponds to 25% of the tank capacity 10Q, is put in. Incidentally, the particle size of the granular purifying material 19 may be 20 mm or less, and particularly, if the particle size is 5 mm or less, the purifying ability is also excellent. Further, when the porosity of the granular purifying material 19 is within the range of 60 to 85%, it exhibits sufficient purifying ability and strength to withstand use. The granular purifying material 19 is suitable because of its high purifying ability and strength. Furthermore, if the amount filled in the tank is less than 50% by volume, the purification ability will be high.
In particular, if the filling amount is in the range of 10 to 30%, the purification ability will be higher and it is preferable.

As this granular purifying material 19, in addition to Tobermoray l-,
For example, a calcium silicate hydrate composed of one or more of zonotri r-, C3H gel, phoshagite, gyrolite, and hireplandite can be used. Among these, L. bamorite, zonotrai),
CSH gel has high pHi binding capacity and a specific surface area of 20-40
It is a preferable granular purifying material because it has a large particle size of 0 m2/g.

Next, how about organic wastewater using the septic tank 1 with the above configuration? Regarding the purification treatment method, the time schedule Ll shown in FIG.
This will be explained accordingly. In addition, in FIG. 2, the timing of each operation for draining raw water, stirring, discharging treated water, and aeration retraction is plotted on the horizontal axis t.

First, granular purifying material 19 was introduced at time t1)
The septic tank 1 is filled with pigsty waste water (raw water) as organic waste water, and pressurized air is blown out from the aeration pipe 26 to stir the raw water for 5 minutes (agitation aeration).

Thereafter, the raw water is allowed to stand for 2 hours without aeration, but an anaerobic state is maintained by stopping the aeration.

Then, at time t2j, two hours after the supply of raw water, aeration is started by blowing out pressurized air (aerobic aeration). This aeration system supplies oxygen and fluidizes the purification material by feeding 2 Q of air into the septic tank per minute. By performing the aeration system, an aerobic state is maintained.

Next, the aeration is stopped at time t3j, which is 4 hours after the start of one aerobic aeration.

Immediately after stopping the aeration, first, 0.50% of raw water is replenished, and along with this, treated water is discharged, and then the inside of the septic tank 1 is stirred by aeration for 5 minutes in the same manner as described above.

After that, repeat the above-mentioned operation, stop the aeration for 2 hours, perform the aeration for 4 hours, and perform rIiI.
Repeat the aerobic state and the aerobic state. The supply of raw water is performed immediately after the aeration is stopped, that is, in each anaerobic state. The interval at which the aerobic state and anaerobic state are repeated is aerobic state period: anaerobic state period = 1:2 to 4:
1, the purification ability is high, and in particular, if the ratio of aerobic state period: anaerobic state period is within the range of 1:1 to 3:1, the purifying ability is even higher and is suitable.

Moreover, if these operations are repeated, the bottom part 32 of the septic tank 1
Since the sludge 18 accumulates in the tank, the discharge pump 34 is driven at predetermined intervals and the sludge 18 is taken out by the discharge vibrator 36. When taking out this sludge 18, the amount of sludge taken out per day IQ
Is it granular compared to j? Replenish 0.5Q of purifying material 19. still,
The supply of raw water is divided into four times of 0.5Q each for 2Q a day.

The above operation has the following effects.

First, the amount of dissolved oxygen (
As is clear from the change in D O), an aerobic state and an anaerobic state can be clearly distinguished depending on whether or not aeration is performed. Furthermore, by discharging raw water after stopping aeration, aerobic microorganisms decompose organic matter in the raw water, reducing dissolved oxygen in the water and causing air pollution. Therefore, purification activities in each state ζ become active.

That is, in an aerobic state, a fine uneven surface is formed on the surface of the porous granular purifying material 19 by the crystals of the calcium silicate hydrate, so that the formation of a biofilm on the surface of the granular purifying material 19 is prevented. This biofilm can be used to remove organic matter from raw water, and can also sufficiently perform dephosphorization and nitrification. In addition, granular purifying material 19
As the particles rub against each other during fluidization, their surfaces are exposed to an appropriate degree, so that extremely high purification performance can be maintained.

In addition, in an anaerobic state, -12= denitrification is performed by denitrifying bacteria and the like. Figure 4 shows the change in dissolved nitrogen amount due to this denitrification. As is clear from this figure, the nitrogen contained in the raw water (60 mg/Q) decreases to 40 mg/Q when the anaerobic condition is maintained for 2 hours. Also,
A part of the granular purification material 19 flows out when the sludge 18 is taken out, but it only needs to be replenished by adding it when the sludge 18 is taken out.

Next, the degree of purification of the treated water obtained by the above treatment is shown in the table below in comparison with the conventional example. The pH of this example
, visibility, biological oxygen demand (BOD), suspended solids (S
S), total nitrogen (TN).

The total phosphorus (TP) data is from the 6th to 8th week after the acclimatization of the purified species 1 was completed. The raw water to be purified was the same wastewater from a pigsty.

As is clear from this table, in this example, the visibility is improved, and the values of BOD, SS, 'r-N, and TP are also significantly reduced.

In this way, in this embodiment, one purification type 1 can serve as an aerobic tank or an anaerobic tank by simply adjusting the execution or stopping of aeration.

In other words, since it is possible to remove suspended solids, decompose organic matter, dephosphorize, nitrify, denitrify, etc. in one tank, the organic wastewater treatment equipment becomes extremely compact and the purification capacity is also improved compared to conventional methods. However, it is not inferior. Therefore, there is a significant advantage that a large purification plant is not required.

Also, only one tank is required, and like when multiple tanks are used,
Since there is no need to circulate organic wastewater, the equipment can be simplified from this point as well.

Furthermore, since the granular purifying material 19 is fluidized by aerobic aeration, the purifying performance does not deteriorate due to clogging, and a high purifying ability can always be maintained.

Furthermore, since the granular purification material 19 is stirred by aeration, the sludge 18 that has accumulated between the granular purification materials 19 and the sludge 18 that has adhered to the granular purification material 19 can be removed by stopping the aeration and allowing it to stand still. sludge 1
8 has good sedimentation properties.

The sludge 18 is also removed from the bottom 3 of the septic tank 1.
It can be easily done by just pulling it out.

In addition, to replace the reduced amount of granular purification material 19, instead of suspending the purification process and replacing it all as is the case in the past, the part that was washed away during the day's sludge removal is put into the septic tank 1. All you have to do is replenish it, and the purification process is not interrupted and is very simple.

Therefore? There is an advantage that maintenance and management of the septic tank 1 is extremely easy.

It should be noted that the present invention is not limited to the above-described embodiments, and can be implemented in any manner without departing from the gist of the present invention.

[Effects of the Invention] As explained below, according to the method of the present invention, one purifying species can function as an aerobic tank and an anaerobic tank to sufficiently purify organic wastewater. At the same time, nitrogen and phosphorus can also be removed. Furthermore, it does not require circulating water and is very easy to maintain. In addition, purification performance can be maintained at a high level at all times, replenishment of purification material is easy, and the sludge produced has good settling properties.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the nitrogen purification apparatus of this embodiment, Fig. 2 is an explanatory diagram showing the purification time schedule, Fig. 3 is a graph showing changes in the amount of D○, and Fig. 4 is a graph showing the change in the amount of nitrogen-IC. It is a graph showing changes in the amounts of ' and -. 1...? Purification (sodium 10...supply purive 19...granular purifying material 22...discharge port 26...dispersion pipe 36...discharge pipe

Claims (1)

[Claims] 1. Purifying organic wastewater while bringing it into contact with a biofilm formed on the purifying material in a tank containing a purifying material whose main component is porous granular calcium silicate hydrate. In the method, the purification treatment is carried out under repeated aerobic conditions and anaerobic conditions, and in the aerobic condition, the purification material is flowed, and further, the supply of organic wastewater to the tank is substantially anaerobic. A method for purifying organic wastewater, which is characterized in that it is carried out below. 2. The porous granular calcium silicate hydrate is tobermorite, xonotlite, CSH gel, phosiyaite,
2. The method for purifying organic wastewater according to claim 1, comprising one or more of gyrolite and hireplandite as a component. 3. The porosity of the porous granular calcium silicate hydrate is
The method for purifying organic wastewater according to claim 1, wherein the concentration is 60 to 85%. 4. The method for purifying organic wastewater according to claim 1, wherein the amount of porous granular calcium silicate hydrate packed in the tank is 50% or less by volume.