KR100200231B1 - Biological activated carbon - Google Patents

Abstract

The present invention relates to water treatment using a carrier in which microorganisms are immobilized, wherein two or more biological packing layers made of a carrier in which microorganisms are immobilized are separated and disposed in a reactor, and raw water is dispersed and injected into a plurality of packs. The removal efficiency of organic matter and ammonia nitrogen can be improved than biological treatment.

Description

Reactor for water treatment in which microorganisms are immobilized with multiple carriers and water treatment method using the same

The present invention relates to a water treatment reactor and a water treatment method using the same while maintaining aerobic conditions for a short empty bed contact time (EBCT) while improving the removal efficiency of organic substances and ammonia nitrogen.

Drinking water and wastewater treatment using microorganisms are very sensitive to the operating conditions of the reactor, so it is necessary to maintain the dissolved oxygen content, removal material and pH at the optimum conditions. The oxidation process of organic materials by microorganisms under general aerobic conditions is shown in Scheme 1.

C _X H _Y + (x + 0.25y) O ₂ → xCO ₂ + 0.5yH ₂ O

As shown in Scheme 1, the theoretical amount of oxygen required to completely convert dissolved organics to CO ₂ and water is (x + 0.25y) O ₂ . However, in the presence of insufficient dissolved oxygen, partial oxidation of organic matter occurs.

In addition, the nitriding process of converting ammonia nitrogen to nitrate nitrogen consists of two steps in which two microorganisms, namely, nitrozomonas and nitrobacter, are activated, and the process is shown in Scheme 2 below.

^{_{NH 4 + + 2O 2 → NO}} 3 - + 2H + + H 2 O

As shown in Scheme 2, the amount of oxygen required to convert 1 mg of ammonium ions into nitrate ions is 3.6 mg, which is an aerobic reaction that requires a large amount of dissolved oxygen.

As such, a large amount of dissolved oxygen is required for the reactions to be carried out under aerobic conditions, and sufficient oxygen must be supplied to all parts of the packed bed to further enhance the efficiency of these reactions.

However, in the existing biological activated carbon treatment method, since most of the dissolved oxygen is used in the upper layer of the carrier packed integrally in the reactor, the amount of dissolved oxygen required for the oxidation and nitrification reaction of organic matter decreases as the lower layer is lowered, thus inhabiting not only the activity of the microorganism but also There is a problem that even the number of microorganisms are sharply dropped.

In addition, in the conventional biological activated carbon treatment method, when a high concentration of organic matter or ammonia nitrogen is introduced into the reactor, denitrification reaction under anaerobic conditions occurs due to deactivation of microorganisms due to overload and reduction of dissolved oxygen, thereby generating nitrogen gas. Due to plugging phenomenon, the pressure drop occurs within a short time, and the number of backwashing increases, so that the microbial activity is not stabilized, thereby greatly reducing the treatment efficiency.

Moreover, in the case of the conventional one-piece filling method, the location of the filler is determined at the time of backwashing according to the specific gravity of the filler.

In order to solve this problem, the present inventors have developed a reactor in which a carrier in which microorganisms are immobilized in a reactor is separated into multiple layers and filled with raw materials into a plurality of layers of the reactor, thereby removing the removal material from the conventional biological treatment method. A treatment method with improved processing efficiency has been developed.

An object of the present invention is to provide a biological reactor and a treatment method using the same to improve the removal efficiency of organic substances and ammonia nitrogen.

Figure 1 shows a comparison of the reactor (BAC2) of the biological activated carbon treatment method of the present invention and the reactor (BAC1) of the conventional biological activated carbon treatment method.

FIG. 2 is a graph showing the removal efficiency of ammonia nitrogen over time in a biological activated carbon reactor.

3 is a graph showing the change of dissolved oxygen amount during the column residence time in the biological activated carbon reactor.

4 is a graph showing the change of ammonia soluble during the column residence time in the biological activated carbon reactor.

In accordance with the above object, the present invention provides a water treatment reactor in which two or more biologically packed layers consisting of carriers immobilized with microorganisms in a reactor are disposed, and a raw water to be treated is dispersedly injected into two or more packed layers of the reactor. to provide.

As the carrier of the present invention, a biologically activated carbon (BAC) or other polymer which can fix microorganisms necessary for filtration can be used.

Since the biological reactor of the present invention includes a plurality of packing layers, the type of carrier may be different for each layer, and when a specific material is to be removed, a carrier having a superior performance is selected and partially filled in the upper layer for treatment effect. Can be further increased.

It is preferable in terms of filtration efficiency to have as many packed beds in the reactor as possible.

In addition, in the biological treatment method of the present invention, the amount of dissolved oxygen in the lower packed layer is increased by dispersing and injecting the raw water having sufficient dissolved oxygen into not only the uppermost packed layer but also a plurality of lower layers thereof. Especially in the case of overload raw water containing excessively contaminants to be treated, the raw water injected into the lower filling layer is combined with the raw water purified in the upper layer and the concentration of organic matter, which is pollutant, is diluted, resulting in stable treatment of microorganisms. do. In addition, because backwashing is partially divided, the expansion rate is further increased even when using the same flow rate, so that the effective backwashing is achieved. In other words, it is possible to reduce the pump operation cost and the amount of water used for backwashing.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

EXAMPLE

Reactor manufacturer

As shown in FIG. 1a, a reactor was prepared by separating and filling biological activated carbon (charcoal activated carbon from Picabiol Co., Ltd.) into 6 layers of 1.3 kg in 6 layers.

Purification of raw water

While maintaining the concentration of ammonia nitrogen at 6-7 mg / l, as shown in FIG. 1a, the top of the packed bed 1 and the packed bed and the packed bed below ((II), (III) and (IV)). Was fed continuously. The injection ratio of each layer of raw water to be injected was (I): 23%, (II): 22%, (III): 33% and (IV): 22%, respectively. Operation conditions were measured at the pilot-scale as shown in Table 1 below.

Compared with FIG. 1 (A), which is a reactor (BAC2) of the novel biological activated carbon treatment method of the present invention, FIG. 1B is a conventional biological activated carbon reactor (BAC1).

FIG. 2 is a graph showing the removal efficiency of ammonia nitrogen over time in a biological activated carbon reactor. As shown here, in the conventional BAC1 reactor, the ammonia nitrogen concentration of the final effluent was 4.5 to 5.6 mg / l, and the removal rate was 12 to 26%. The nitrogen concentration was 4.0 to 5.2 mg / l, indicating that the removal rate was increased by 16 to 40%. In addition, it can be seen that in the reactor using the biologically activated carbon treatment method of the present invention, the activity and number of microorganisms increase over time, thereby improving the removal rate of ammonia nitrogen.

3 is a graph showing the change of dissolved oxygen amount during the column residence time in the biological activated carbon reactor. Here, in the existing BAC1 reactor, almost all of the dissolved oxygen rapidly decreases between 5 to 10 minutes of the tower residence time, and after 25 minutes, it becomes almost 0, thereby becoming an anaerobic condition in which nitriding reaction cannot occur. In the BAC2 reactor using activated carbon treatment, dissolved oxygen was kept constant throughout to maintain aerobic conditions in which nitrification could occur.

4 is a graph showing the change of ammonia nitrogen during the column residence time in the biological activated carbon reactor. In the conventional BAC1 reactor, ammonia nitrogen was rapidly decreased during the initial tower residence time of 5 minutes and remained almost constant after 10 minutes, so that no further nitriding reaction occurred, but BAC2 using the biologically activated carbon treatment method of the present invention In the reactor, as the tower residence time increases, the concentration of ammonia nitrogen is gradually decreased, so that the nitriding reaction occurs in the lower packed layer. This shows that in the biological reactor of the present invention, dissolved oxygen required for the nitriding reaction is maintained above a certain level in the lower packed layer as well as the upper packed layer.

In addition, as a result of examining the removal efficiency of ammonia nitrogen while changing the raw injection ratio injected into each layer of the BAC2 reactor, it was more preferable to make each injection ratio of raw water similar. This is understood to be due to the same reasons that the BAC2 reactor using the biologically activated carbon treatment method of the present invention is efficient at overload.

According to the present invention, by separating and filling a carrier in which a microorganism is immobilized in a multi-layered reactor, and dispersing and injecting raw water into a plurality of packs, it is possible to increase the treatment efficiency in removing organic substances and ammonia nitrogen than conventional biological treatment methods. Many applications are expected in water treatment facilities.

Claims (3)

A reactor for water treatment comprising two or more biological packing layers made of a carrier having a microorganism immobilized therein and a raw water supply part for dispersing and injecting raw water to be treated on top of each packing layer. The reactor of Claim 1, wherein the carrier is activated carbon. And separating and disposing two or more biological packing layers made of a carrier in which microorganisms are immobilized in the reactor, and dispersing and injecting raw water to be treated on top of each packing layer.