KR20030035962A - Method for disposing of livestock waste water - Google Patents

Abstract

PURPOSE: A treatment method of livestock wastewater is provided, which can reduce plenty of nitrogen by a simple and low cost method without deteriorating activation of nitrifying microorganisms such as nitrosomonas and nitrobacter at the existing facility and enables a steady treatment of wastewater by greatly reducing microorganism load without any seasonal impacts. CONSTITUTION: The treatment method comprises the steps of decomposing and oxidizing ammonia nitrogen by feeding wastewater to aeration tank to raise the pH to more than 10 followed by adjusting to 7.0 to 8.0 to remove organic matter and ammonia nitrogen contained in wastewater; feeding coagulants such as ferric chloride or PAC to the aerated wastewater until the pH of the wastewater is adjusted to pH 4-5 to remove the residual phosphorus and solid; solid/liquid separation; feeding powdery activated carbon to the wastewater to remove colors and suspended solids; and treating the wastewater in biological treatment facilities.

Description

Livestock Wastewater Treatment Method {METHOD FOR DISPOSING OF LIVESTOCK WASTE WATER}

The present invention relates to a method for treating livestock wastewater, and more particularly, it is possible to treat wastewater more simply and inexpensively using conventional equipment, and in particular, to significantly reduce the load of microorganisms and to enable stable wastewater treatment. The present invention relates to a method for treating livestock wastewater which can improve the residual color of effluent and removal rate of suspended solids.

Among the many causes of water pollution, livestock wastewater accounts for only 0.7% of total wastewater, but 8% of BOD (biological oxygen demand) is known. In order to prevent serious water pollution caused by livestock wastewater, various methods have been introduced and implemented. However, none of the methods has satisfied the current effluent standard.

The main cause of this result is that the total amount of nitrogen in the wastewater is so high that basically two steps of reaction are necessary to biologically remove the nitrogen present in the wastewater. The first stage is nitrification, in which ammonia nitrogen is oxidized to nitrate nitrogen, and the second stage is denitrification, which converts nitrate nitrogen into nitrogen gas and releases it into the atmosphere. . Therefore, the removal of nitrogen in water means that the denitrification reaction is completed and finally converted to the nitrogen gas state, which can be carried out only after the nitrification reaction is carried out. The major microorganisms involved in nitrification reactions are nitrosomonas and nitrobacter. They are separated into autotrophs because the energy needed for growth is obtained by the oxidation of inorganic nitrogen. Nitrozomonas oxidizes ammonia nitrogen to nitrite, and nitrobacter oxidizes the nitrite produced by nitrozomonas to nitrate. Therefore, in order to complete the nitrification reaction, two successive reactions must be performed, and the appropriate environmental conditions for nitrozomonas and nitrobacter symbiosis must be satisfied in the water treatment.

However, the denitrification reaction is not easy because the nitrogen in the livestock wastewater is relatively higher than that of BOD, and the high nitrogen concentration adversely affects nitrozomonas, making nitrification difficult, and consequently, NH ₄ N in the treated water. , NO ₂ N, and NO ₃ N concentrations increase.

Conventional livestock wastewater treatment methods include sequencing batch reactor (SBR), C-SBR, and the like. The SBR process that directly treats livestock wastewater is difficult to denitrify because of high NH ₄ N and low C / N (COD / TKN) ratio in the treated water due to the inhibition of nitrification by the excess nitrogen (NH ₄ N) in the reactor. There is a problem that the nitrogen removal efficiency is low because the NO ₃ N in the water. In addition, the C-SBR method of injecting insufficient carbon has a problem that the nitrogen removal efficiency is excellent, but the wastewater treatment period is long.

In addition, as a method for treating livestock wastewater, Korean Patent No. 254998 discloses an excess nitrogen removal step of removing nitrogen by converting nitrogen into ammonia and removing oxygen before nitrification and denitrification by microorganisms, and maintaining a tension state of oxygen. Although it describes a livestock wastewater treatment method consisting of a microbial reaction step and a drug injection step to adjust the nitrification step to increase the denitrification efficiency, this method has a problem that it is difficult to expect stable wastewater treatment due to the high microbial treatment load.

In order to solve the problems as described above, the present invention can be easily and inexpensively removed a large amount of nitrogen without inhibiting the action of the nitrification microorganisms using conventional equipment, as well as significantly reducing the load of microorganisms stable wastewater It is an object of the present invention to provide a method for treating livestock wastewater which enables the treatment and improves the residual color of the effluent and the removal rate of suspended solids.

In order to achieve the above object, the present invention is a livestock wastewater treatment method,

a) Increase the pH of the wastewater to 10 or more by introducing the wastewater into the aeration tank

After adjusting to 7.0 to 8.0, organic matter and ammonia in wastewater

Decomposing and oxidizing noble nitrogen;

b) pH is 4 to 5 by adding a flocculant to the waste water aerated in step a)

Agglomeration until to remove residual phosphorus and solids;

c) solid-liquid separation of the wastewater aggregated in step b); And

d) the wastewater separated from the solid-liquid separated in step c) into the aeration tank

Processing steps

It provides a method for treating livestock wastewater comprising a.

In addition, the present invention is a livestock wastewater treatment method,

a) Increase the pH of the wastewater to 10 or more by introducing the wastewater into the aeration tank

After adjusting to 7.0 to 8.0, organic matter and ammonia in wastewater

Decomposing and oxidizing noble nitrogen;

b) pH is 4 to 5 by adding a flocculant to the waste water aerated in step a)

Agglomeration until to remove residual phosphorus and solids;

c) solid-liquid separation of the wastewater aggregated in step b); And

d) the powder activated carbon remaining in the solid-liquid wastewater separated in step c)

Removing chromaticity and suspended solids; And

e) the wastewater separated from the solid-liquid separated in step d) into the aeration tank

Processing steps

It provides a method for treating livestock wastewater comprising a.

Hereinafter, the present invention will be described in detail.

In the treatment of livestock wastewater, the present inventors were able to remove a large amount of nitrogen, and while researching a method for maximizing the activity of microorganisms, the wastewater was introduced into an aeration tank to raise the pH of the wastewater to 10 or more. After adjusting to 7.0 to 8.0, a flocculant was added thereto to coagulate until the pH was 4 to 5, solid-liquid separation, and then put into an aeration tank and treated with microorganisms. In addition to being able to process, it was confirmed that the residual color of the effluent and the removal rate of the suspended solids were significantly improved, and based on this, the present invention was completed.

In the livestock wastewater treatment method of the present invention, the wastewater source water is introduced into the aeration tank to increase the pH of the wastewater source to 10 or more, and then adjusted to 7.0 to 8.0 to decompose and oxidize organic matter and ammonia nitrogen in the wastewater, and then a flocculant is added thereto. It is characterized by removing the phosphorus and solids by adding agglomerated until the pH is 4 to 5, separating the solids and solid-liquid separation, and then put into an aeration tank to remove nitrogen by the endogenous breathing action of the microorganisms contained in the aeration tank. .

The treatment method of the livestock wastewater of the present invention will be described in detail as follows.

a) adjusting the pH by adding wastewater to the aeration tank (pH 10 or higher → pH 7 ~ 8)

In this step, the wastewater source water is introduced into the aeration tank to raise the pH of the wastewater source to 10 or more through aeration and then lower it to 7-8. By adjusting the pH through the aeration can be decomposed and oxidized organic matter and ammonia nitrogen contained in the waste water.

The wastewater source water is preferably raw water from which the precipitate is removed through the screen. The ammonia nitrogen present in the wastewater is converted to ammonia and removed through the wastewater aeration. The aeration is preferably carried out until the pH rises to 10 or more and the pH reaches 7 to 8, more preferably until the pH reaches 7.5 to 8. Typically, the period of time until the pH is in the above range is about 5 days. When the pH of the wastewater source water raised through the aeration is not raised above 10, there is a problem that the amount of ammonia nitrogen removed through the aeration is too small. In addition, when the pH of the lowered wastewater exceeds 8, there is a problem in that the treatment efficiency is lowered when treating microorganisms, and when the pH is lower than 7, the removal effect of organic matter and ammonia nitrogen due to aeration is inhibited, resulting in excessive cost and enlargement of equipment. There is a problem that causes.

b) flocculation

In this step, a flocculant is added to the aerated wastewater of pH 7 to 8 to aggregate until pH is 4 to 5 to remove phosphorus and solids remaining in the wastewater.

As the flocculant, a flocculant used for normal wastewater treatment is used, and it is preferable to use ferric chloride or PAC. The amount of the flocculant is usually added to 3 to 5 mL with respect to 500 mL of wastewater, and the aggregation time is within a few minutes.

If the pH of the wastewater exceeds 5 after the flocculant is added, there is a problem in that residual color removal and organic matter removal are not performed well. If the concentration is less than 4, the post-treatment process may be caused due to the over-injection of chemicals and the residual chemicals. Microbial treatment through aeration) is difficult.

c) solid-liquid separation

This step is a step of solid-liquid separation by treating the chemical to the flocculated waste water of pH 4 to 5.

The drug is a drug used in conventional wastewater treatment, and preferably a polymer coagulant. The dosage of the drug is preferably 8 to 10 mL with respect to 500 mL of waste water.

d) microbial treatment

This step is a step of treating the microorganisms by putting the solid-liquid separated wastewater into the aeration tank.

The microorganisms in the aeration tank maximize the activity in the aeration tank to remove contaminants through active metabolism in contact with high concentrations of organic matter.

The microbial treated wastewater is discharged through post-treatment such as precipitation.

In addition, the present invention may further perform the step of adding the powdered activated carbon to the solid-liquid separated wastewater prior to the microbial treatment step through the aeration.

The powdered activated carbon has a great influence on the removal of suspended solids depending on the step of being injected, and most preferably, it is performed between the solid-liquid separation and the microbial treatment step through aeration.

The wastewater treated with the powder activated carbon is not only significantly improved the residual color and the removal rate of suspended solids, but also stabilizes the microorganisms during microbial treatment through aeration.

According to the treatment method of the present invention, it is possible to remove a large amount of nitrogen simply and inexpensively without inhibiting the action of nitrifying microorganisms using conventional equipment, and to significantly reduce the load of microorganisms and to enable stable wastewater treatment. In addition, the residual color of the effluent and the removal rate of the suspended solids can be improved. In addition, the treatment method of the present invention does not react sensitively to temperature changes, and is not significantly influenced by seasonal factors, thereby providing a stable effect.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

EXAMPLE

Example 1

After separating the solids from the livestock wastewater through the screen, they were placed in a storage tank and aerated through the aeration system. The aeration was carried out until the pH of the wastewater rose to 10 and reached 8.0. The duration was 5 days. After aeration, 4 mL of ferric chloride was used as a flocculant and the flocculation reaction was performed until the pH of the wastewater reached 4.0. After the flocculant treatment, the wastewater was chemically treated with 9 mL of the polymer coagulant. Subsequently, the chemically treated wastewater was treated with microbial reactor in parallel with PACT for 48 hours and then microorganisms were separated to obtain final effluent.

Example 2

Except that the aeration in the storage tank in Example 1 until the pH was 11 was carried out in the same manner as in Example 1.

Example 3

In the same manner as in Example 1 except that the aggregation reaction in Example 1 was carried out until the pH is 4.5.

Example 4

Powder activated carbon was added to the wastewater treated with the polymer coagulant in Example 1, followed by treatment, followed by the same method as Example 1 except that the microorganism treatment was performed through aeration.

Comparative Example 1

The wastewater was treated in the same manner as in Example 1, except that the livestock wastewater was not screened and then aerated, and the coagulant used in Example 1 was added in the same amount.

Comparative Example 2

After adding the flocculant in Example 1, the microbial treatment step was performed immediately without chemical treatment to treat wastewater.

Comparative Example 3

In Example 1, the procedure of the drug treatment was performed in the same manner as in Example 1 except that the procedure of the microbial treatment was performed after the step.

Comparative Example 4

In Example 4, the powder activated carbon was added in the same manner as in Example 1, except that the microbial treatment was performed after the microbial treatment step.

BOD, T-N, COD, SS, and chromaticity were measured using the final effluent water treated in Example 4 and Comparative Example 4, and the results are shown in Table 1 below.

division Example 4 Comparative Example 4 1st Aeration → After Solid Solution After final treatment BOD 120 ppm 20 ppm 50 ppm T-N 140 ppm 70 ~ 80 ppm 700 ~ 800 ppm SS 10-20 ppm 20 ppm or less 50 ppm COD 200 ppm 70 ~ 80 ppm 1000 ppm or more Chromaticity - 5 degrees or less 2000 degrees

Through Table 1, the BOD, TN, SS, and COD of the effluent of Example 4 treated according to the method of the present invention are superior to the effluent of Comparative Example 4, and the livestock wastewater treatment criteria (BOD: 50 ppm or less, TN: 260 ppm or less, SS: 50 or less). In addition, the effluent water of Example 4 according to the present invention showed chromaticity (5 degrees or less) of the tap water level, and thus, it was confirmed that the residual color removal effect of the wastewater was excellent.

According to the present invention, it is possible to remove a large amount of nitrogen simply and inexpensively without inhibiting the action of nitrifying microorganisms by using a conventional facility, to significantly reduce the load of microorganisms, to enable stable wastewater treatment, and In addition to improving the residual color and removal rate of suspended solids, there is an effect that the livestock wastewater can be treated stably because it is not significantly affected by seasonal factors.

Claims (3)

In the livestock wastewater treatment method, a) Increase the pH of the wastewater to 10 or more by introducing the wastewater into the aeration tank After adjusting to 7.0 to 8.0, organic matter and ammonia in wastewater Decomposing and oxidizing noble nitrogen; b) pH is 4 to 5 by adding a flocculant to the waste water aerated in step a) Agglomeration until to remove residual phosphorus and solids; c) solid-liquid separation of the wastewater aggregated in step b); And d) the wastewater separated from the solid-liquid separated in step c) into the aeration tank Processing steps Livestock wastewater treatment method comprising a. The method of claim 1, Process for treating livestock wastewater, wherein the coagulant is ferric chloride, or PAC in step b). Provide a treatment method for livestock wastewater. In addition, the present invention is a livestock wastewater treatment method, a) Increase the pH of the wastewater to 10 or more by introducing the wastewater into the aeration tank After adjusting to 7.0 to 8.0, organic matter and ammonia in wastewater Decomposing and oxidizing noble nitrogen; b) pH is 4 to 5 by adding a flocculant to the waste water aerated in step a) Agglomeration until to remove residual phosphorus and solids; c) solid-liquid separation of the wastewater aggregated in step b); And d) the powder activated carbon remaining in the solid-liquid wastewater separated in step c) Removing chromaticity and suspended solids; And e) the wastewater separated from the solid-liquid separated in step d) into the aeration tank Processing steps Livestock wastewater treatment method comprising a.