KR100673831B1 - Treatment methods of swine wastewater, landfill leachate and night soil - Google Patents

Abstract

A method capable of protecting an ecosystem and effectively protecting the nature by effectively treating wastewater containing high concentration organic matters, nitrogen, phosphorous and the like such as livestock wastewater, leachate and excretions is provided. A method for treating wastewater such as livestock wastewater, leachate and excretions comprises: reacting wastewater supplied into a reaction tank(2) with a catalyst in which magnesium is mixed with calcium, thereby producing MgNH4PO4À6H2O and Ca10(OH)2(PO4)6 to primarily treat wastewater by removing ammonia nitrogen, phosphorous, solids and nitrogen; removing organic matters from the primarily treated water in an organic acid tank(3) and a methane fermentation tank(4) in which methane-producing bacteria are filled to secondly treat the treated water; injecting the secondly treated water into a nitrification tank(5) charged with nitrifying bacteria to thirdly treat the secondly treated water by converting ammonia nitrogen into nitrate nitrogen or nitrite nitrogen in the nitrification tank and removing ammonia; and injecting the thirdly treated water into a denitrification tank(9) charged with sulfur-nitrifying bacteria to thirdly treat the wastewater by converting nitrate nitrogen or nitrite nitrogen into nitrogen gas in the denitrification tank and removing nitrogen.

Description

Wastewater treatment methods such as livestock wastewater, leachate and manure {Treatment methods of swine wastewater, landfill leachate and night soil}

1 is a schematic diagram illustrating a wastewater treatment method according to the present invention.

2 and 3 is a reference block diagram showing an embodiment of the present invention.

The present invention relates to a wastewater treatment method, such as livestock wastewater, leachate and manure, more specifically, livestock wastewater, leachate and manure for treating organic matter such as livestock wastewater, manure, leachate, nitrogen, phosphorus It relates to a wastewater treatment method such as.

In general, livestock waste, manure and leachate contain not only high concentrations of organic matter but also high concentrations of organic nitrogen, ammonia nitrogen, and phosphates such as phosphorus, magnesium and calcium (Am. Soc. Civ). Engrs.Trans., Vol. 18, p. 340-343, 1975).

Among them, livestock wastewater, manure, and leachate are treated in a complex treatment process as shown in Table 1, but the reality is that they do not obtain satisfactory treatment efficiency compared to complex treatment processes.

Treatment process according to the substance to be removed Substances to be removed Treatment method Primary treatment (pretreatment) Solids (SS) Physical method (sedimentation, flotation, screen, etc.) Secondary processing (this processing) Dissolved Organics (BOD, COD) Biological methods (anaerobic treatment, aerobic treatment, etc.) 3rd process (advanced processing) Nitrogen (N) Biological method (nitric oxide denitrification) Phosphorus (P) Chemical Method (Agglomeration Separation, etc.) Hardly degradable substance (color, COD) Physical method (activated carbon adsorption method, reverse osmosis membrane method, etc.) Sludge treatment (after treatment) Separated sludge Physical methods (sedimentation, concentration, dehydration, etc.)

Therefore, it is necessary to understand the advantages and disadvantages of the existing treatment system and to configure the treatment system by selecting the optimum treatment process suitable for the treatment of each material to be removed.

In the livestock wastewater, manure and leachate treatment, the anaerobic treatment is the most effective in the secondary treatment (main treatment) for removing organic matter.

However, the anaerobic treatment method is insufficient in the removal of nitrogen and phosphorus, there is a problem that the treatment efficiency is lowered if the influent of the anaerobic treatment method contains a high concentration of ammonia nitrogen. Therefore, it is necessary to remove ammonia nitrogen before the anaerobic treatment.

Aerobic treatment methods include activated sludge method, activated sludge method (AO method, A2O method, membrane separation activated sludge method, etc.), biofilm method (contact oxidation method, rotating disc method, etc.), batch activated sludge method, and oxidative method (법). Establishment and Determination Guide Block, Deposition, p. 13, 2004).

The aerobic treatment method requires a long site and a large site if the organic matter (BOD) concentration is 3,000 mg / L or more, or the organic matter and nitrogen ratio (C / N ratio) is 5 or less or 10 or more. There is a problem.

In the case of tertiary treatment (advanced treatment), nitrogen removal is mainly performed by a combination of nitrification using autotrophic microorganisms and denitrification using heterotrophic microorganisms.

Nitrification is a process in which ammonia (NH ₄ ⁺ -N) is converted to nitrite nitrogen (NO ₂ ^-- N) or nitrate nitrogen (NO ₃ ^-- N) by autotrophic microorganisms, which can be oxidized from ammonia to nitrite. Nitrosomonas, Nitrosococcus, Nitrosobacillus, and other microorganisms are involved, and when nitric acid is oxidized to nitric acid, Nitrobacter and Nitrosocystis are involved.

The nitrification requires oxygen, and a large amount of nitrifying microorganisms must be secured and maintained in the reactor.

In addition, a large amount of alkalinity is required, so a pH buffer is required to control the lowering pH.

Temperature, BOD / N ratio, and ammonia concentration also influence nitrification.

Denitrification is a process in which nitric acid or nitrous acid is converted to nitrogen gas (N ₂ ) by heterotrophic organisms such as Pseudomonas, Bacillus, and Micrococcus in anoxic state in which no dissolved oxygen (DO) is present but nitric acid or nitrous acid is present. Say.

Denitrification requires an organic carbon source as the electron donor.

At present, the most common nitrogen removal method is circulating nitrification and denitrification using suspended activated sludge.

This method consists of oxygen-free aerobic tank and circulates the waste water so that denitrification in anoxic tank and nitrification occur in aerobic tank.

However, this method requires a separate installation of the reactor, so a large installation site is required and the aerobic capacity must be increased.

In order to obtain stable treated water with a small reaction tank volume, a method of filling activated sludge or a carrier immobilized with nitrifying or denitrifying bacteria is also used instead of suspended activated sludge.

However, there is a disadvantage that the carrier cost is high.

    As a method of nitrifying and denitrifying in a single bath, there is a batch activated sludge process (SBR process).

This process is a variation of the activated sludge method, in which five processes of [inflow-reaction-precipitation-discharge-atmosphere] are sequentially performed in one reactor, and in the precipitation process, aeration is stopped to form an oxygen-free tank to perform denitrification.

This process has the advantage of a simple device, easy maintenance and low installation and operating costs.

However, scum is easy to accumulate in the reactor and a discharge device of supernatant is required.

In any of the above-described methods, wastewater with high nitrogen concentration and low organic matter concentration, that is, low C / N ratio, requires much energy to supply oxygen for nitrification, and an electron donor must be added for denitrification.

The most commonly used is methanol.

However, in the case of methanol addition, it is difficult to control the proper amount of addition, and methanol remains in the treated water due to the toxicity of methanol itself, which causes secondary contamination.

Typically, the amount of methanol requires more than three times the amount of nitrogen to be treated, and the maintenance costs cannot be ignored.

Sulfur denitrification, which has been recently attracting attention, is characterized in that nitrates are produced using oxygen, which is bound to nitrate or nitrite, as the oxygen component required to be sulfated during the oxidation of sulfurized microorganisms represented by Thiobacillus denitrificans . It is the reaction to remove nitrogen component in water by converting cow or nitrite nitrogen into nitrogen gas.

Sulfation denitrification can only be expected in an anoxic state in which no oxygen is present and either nitrate nitrogen or nitrite nitrogen is present.

Sulfated denitrifying microorganism an absolute chemical stand in nutrient microorganism CO _2, HCO ₃ ^- and grown with the inorganic carbon in the carbon source, such as, CO ₃ ^2-.

Comparison of the cost of the sulfur compounds in drug costs per electronic equivalent as a hydrogen acceptor in a sulfur denitrification reaction by the T. denitrificans, it is reported that S ^O is the most cost-effective hydrogen donor (Bisogni, JJr & Driscoll, CT Jr.: Denitrification using thiosulfate and sulfide, J. Environ. Eng. Div. Proc. ASCE, Vol. 103, p. 593-604 (1977)).

S ^O is resource rich, low-cost prices, good handling, easy to save, but the advantages of non-toxic, there is a disadvantage does not dissolve readily in water.

In addition, sulfated denitrification microorganisms are known to be difficult to accumulate and solid-liquid separation of microorganisms due to their cohesiveness.

In addition, sulphate ions, the final product of the sulphation reaction, lower the pH, and when the pH is 5.5 or less, there is a problem in that the denitrification reaction is inhibited and the alkalinity must be continuously replenished.

There is a technology developed by the present inventors (Patent No. 0503134) to solve the problems of the above-mentioned desulfurization denitrification method, which is a conventional sulfate by using an integrated carrier prepared by melting sulfur and alkaline substances. All problems caused by denitrification have been solved.

And the removal of phosphorus is mainly a chemical treatment method using a flocculant and a polymer, but there is a problem in that the operating cost of the operation is high according to the drug usage.

In addition, in the biological treatment of the primary treatment may be treated by repeating the anaerobic treatment and aerobic treatment, there is a problem that the removal amount is insufficient compared to the amount to be removed.

In the case of hardly decomposable materials, the most problematic is chromaticity.

Livestock wastewater and manure have a brown color derived from humic acid, which is rarely removed by primary, secondary and tertiary treatments.

In order to remove the color, the phenton oxidation method, ozone treatment method, electrolysis method, etc. are used, but excessive treatment cost is a problem compared to removal efficiency such as chemical cost and electric charge.

     The present invention has been drawn to solve the problems of the prior art as described above is an object of the present invention is to treat livestock wastewater, manure, leachate, in particular, high concentrations of organic matter, such as livestock wastewater, manure, leachate, nitrogen, phosphorus It is for the treatment of waste water.

In order to achieve the above object, the present invention aims to remove ammonia nitrogen, phosphorus and solids through the reaction tank, to remove organic matter from the organic acid tank and the methane fermentation tank, and to replace the ammonia nitrogen in the nitrification tank with nitrate nitrogen or nitrite. It was possible by treating wastewater through a method of removing ammonia by converting to nitrogen and removing nitrogen by converting from nitrate nitrogen or nitrite nitrogen to nitrogen gas in a denitrification reactor.

Generally in Korea, livestock wastewater and manure are sent to sewage treatment plants after biological treatment or chemical and physical treatment.

Since sewage in domestic sewage treatment plants has a low C / N ratio and is difficult to treat biologically, it is encouraged to treat livestock wastewater or manure with high organic matter concentration.

However, the livestock wastewater and manure contain high concentrations of organics and ammonium (NH ₄ ), phosphate (PO ₄ ), magnesium (Mg) and calcium (Ca).

These components are present in high concentrations even after treatment in livestock wastewater treatment or manure treatment plants.

Therefore, organic matter depleted in sewage by livestock wastewater or manure introduced into the sewage treatment plant is replenished, but in most cases, the nitrogen and phosphorus loads increase and the treatment capacity of nitrogen and phosphorus in the sewage treatment plant is exceeded.

As a result, current sewage treatment plants are reluctant to constantly inflow of livestock wastewater or manure.

In order to solve the above problems, it is necessary to further remove nitrogen and phosphorus from the livestock wastewater treatment plant or manure treatment plant.

In this case, biological sewage treatment will be performed more smoothly because there are suitable organic materials and low concentrations of nitrogen and phosphorus in the livestock wastewater and manure to increase the C / N ratio of the sewage.

Referring to the accompanying drawings, the present invention for solving this problem will be described in detail as follows.

In the present invention, the wastewater supplied from the raw water storage tank (1) is to remove ammonia nitrogen, phosphorus and solids at the same time in the reaction tank (2).

In the reaction tank (2) of the present invention, if ammonium, phosphate, and magnesium are present, the phosphate and ammonium present in the water are reacted by using a chemical reaction to form crystals in the form of magnesium phosphate (Phosphate Magnesium Ammonium). Nitrogen and phosphorus are removed using the principle of removal, and solids are precipitated.

_{^{HPO 4 2 - + NH 4 +}} + Mg 2 + + OH - + 6H 2 O → MgNH 4 PO 4 6H 2 O ↓ + H 2 0

In addition to the crystallization of the MgNH ₄ PO ₄ 6H ₂ O and to form a crystal of calcium hydroxide (Hydroxyl Apatite) to remove the phosphorus.

_{^{6HPO 4 2 - + 10Ca 2 +}} → Ca 10 (OH) 2 (PO 4) 6 ↓ + 6H2O

As a basic condition for the reaction of MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ to occur, ① a large amount of ① ammonium, phosphate, magnesium, calcium should be present, ② pH is 8 Should be higher than

Although there are differences according to the treatment method of livestock manure (Scrap type, Slurry type) in feed or barn, in general, in the case of livestock wastewater, ammonium concentration is 400 ~ 1,200 mg / L, phosphate concentration is 50 ~ 400 mg / L, magnesium Concentration is 50 ~ 300mg / L, calcium concentration is about 50 ~ 300 mg / L.

Manure also tends to be similar to livestock manure or higher in ammonium and phosphate. Most of the pH is 7 or more.

That is, if the pH is adjusted to 8 or more, the reaction with MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ may be facilitated, thereby removing nitrogen and phosphorus in water. have.

As such, if nitrogen and phosphorus are removed to some extent and the livestock wastewater or manure is sent to the sewage treatment plant, the nitrogen and phosphorus load in the sewage treatment plant is small, and the organic concentration is supplemented to maintain the appropriate C / N ratio for biological treatment. Is more smooth.

In the present invention, the reaction of MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ may be more easily generated, thereby increasing nitrogen and phosphorus removal efficiency.

Therefore, in the present invention, ① aeration in the reaction tank (2) by administering an acid engine to easily maintain a pH of 8 or more, ② attach a catalytic reactor in the form of a cartridge to replenish the magnesium and calcium which may be insufficient The catalyst charged inside the catalytic reactor is prepared by mixing magnesium, calcium as much as necessary, mixing, melting, and then crushing and fractionating to prepare pellets to slowly elute the necessary components during the reaction. and to give supplements, it crystallized ③ to recover MgNH ₄ PO ₄ 6H ₂ O and _{Ca 10 (OH) 2 (PO} 4) 6 material is precipitated separately from the solid substance _{(SS) MgNH 4 PO 4 6H} 2 A stainless steel mesh is installed to attach the O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ materials, and the MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ materials must be installed inside the pipe. Even if it can't attach Use a rubber material.

As described above, the reaction vessel 3 removes some phosphorus, solid matter and ammonia nitrogen.

The treated water treated in the reaction tank (3) of the present invention is transferred to the organic acid tank (circulating water tank) 3 and the methane fermentation tank (4).

In the organic acid tank (circulating water tank) (3) and the methane fermentation tank (4) in the present invention, the treated water is treated while circulating the first treated water, wherein the methane fermentation tank (4) is Methanothrix and By administering granules formed of the same methane-producing bacteria, the methane gas is generated by reacting with the organic matter contained in the treated water, and the methane gas is collected separately.

That is, it can be seen that the organic acid tank (circulating water tank) 3 and the methane fermentation tank 4 process organic substances contained in the treated water.

At this time, the organic acid tank (circulation water tank) (3) and the methane fermentation tank (4) circulates the treated water but the flow rate is increased to allow the flow of granules formed of methane-producing bacteria such as Methanothrix to perform the contact area with the treated water. Maximization can increase the removal efficiency of the organic matter.

Meanwhile, the methane gas generated above may be collected together with carbon dioxide and H ₂ S generated while the organic matter is decomposed, collected through the desulfurization device 6, and collected in the gas holder 7. The methane gas may be used as a fuel. .

The secondary treated water in the state of removing the organic matter is moved to the nitrification tank (5) again.

The nitrification tank 5 is for treating ammonia nitrogen remaining in the secondary treated water.

It is treated with nitric oxide such as Nitrobactor or Nitrosomonas to the nitrification tank 5 to react with the second treated water to treat ammonia or ammonia nitrogen.

Ie NH ₃ + Nitrifying bacteria → NO ₃ → NO ₂

The tertiary treated water treated in the nitrification tank 5 is transferred to the denitrification tank 9 through the precipitation tank 8 again.

The above-described denitration reactor (9), the zoom blow the N ₂ gas to generate N ₂ gas react with the NO _3, NO ₂ dissolved in sulfated denitrifying microorganisms (Thiobacillus denitrificans), the above treatment tertiary administered As a result, the nitrogen remaining in the tertiary treated water is removed.

By discharging the fourth treated water from which such nitrogen is removed, wastewater, in particular, wastewater containing high concentrations of organic matter such as livestock wastewater, manure, and leachate, nitrogen, phosphorus, etc., is effectively treated.

In the course of the present invention, the reaction tank 2 is preferably configured as shown in FIG. 2.

That is, a structure in which a division tank 101 made of a rubber material is installed in the reaction tank 2 to install an diffuser 102 receiving oxygen therein, and a plurality of stainless steel nets 103 are installed thereon. It consists of.

At this time, the outlet of the reactor 2 is provided with a discharge port 105, the valve 104 is installed, and the inflow path 100 for introducing the waste water supplied from the raw water storage tank 1 of the reactor 2 Into the stainless steel network 103 of the one side through the upper portion, but the treated water is moved through the circulation pipe 106 through the upper portion of the reaction tank 2 again passes through the catalyst tank 107 filled with magnesium and calcium. It is made of a structure to be mixed with the wastewater passing through one inlet 100 and at the same time to move to the organic acid tank (3).

Through this structure, the MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ generated by the reaction as described above are aggregated in the stainless steel network 103, and some of the above-mentioned non-aggregation are performed. MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ are precipitated with the solids and are thus removed via outlet 105.

That is, in the reaction tank 2, the wastewater supplied through the inflow passage 100 is introduced into the stainless steel network 103 located on one side to treat the wastewater through reaction with ammonia nitrogen and phosphorus in the wastewater as described above. This is because the waste water introduced into the reaction tank (2) through the circulation pipe 106 continuously performs a circulation action accompanied with magnesium and calcium charged in the catalyst tank 107 by the above-described action MgNH ₄ Ammonia nitrogen and phosphorus are removed while producing PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ .

In addition, the diffuser 102 is intended to facilitate a smooth reaction through the supply of air and to increase the dissolved oxygen rate in the treated water.

In particular, the compartment 101 of the rubber material in the present invention, as mentioned above, while the solid and MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ is not attached to the stainless steel net It is intended to increase the collection rate by inducing to gather only at (103).

That is, since MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ is a component used as a fertilizer is necessary for its efficient collection.

The well oxidation tank 5 for converting the ammonia nitrogen remaining in the treated water into nitrate nitrogen or nitrite nitrogen is preferably the structure as shown in FIG.

That is, in order to prevent outflow of nitrifiers, such as Nitrobactor or Nitrosomonas , which are introduced into the nitrification tank 5, the inlet 200 and the lower part are formed narrowly, but the central part is formed in the shape of the mid-low light narrowing which has a wide central part. It consists of the structure which installed 102.

In particular, in the case of nitrification bacteria such as Nitrobactor or Nitrosomonas is sensitive to temperature, the insulating layer 201 may be provided on the outside of the nitrification tank 5 as necessary.

In addition, in the case of the nitrifiers such as Nitrobactor or Nitrosomonas it is necessary to immobilize for use, in the present invention is to immobilize the nitrifiers such as Nitrobactor or Nitrosomonas through the following method.

That is, polyvinyl alcohol (PVA) is added to water, and then adjusted to a final concentration of 20%.

The 20% PVA thus adjusted is sterilized and melted at 120 ° C. for 5 minutes using an autocrep.

The 20% PVA aqueous solution was cooled to 30 ° C. at room temperature, and then, the above-mentioned nitrifying bacteria were cultivated so that the concentration of the PVA aqueous solution was 10%, and the mixture was uniformly mixed at a ratio of 1: 1.

The mixture is uniformly injected into a metal box to have a constant thickness and frozen at -4 ° C for 24 hours.

After thawing at room temperature, cut to a size of 3 to 5mm and use the carrier of the cube.

In this immobilization method, the polyvinyl alcohol (PVA) is not converted into a 20% PVA aqueous solution, or the mixture with sludge in the form in which the above-mentioned nitrifier is incubated is 1: 1, and the concentration is not maintained at 10%. If it is maintained at a concentration below that, it does not harden during freezing and easily melts when administered to the nitrification tank 5, and if it is maintained at a higher concentration, it becomes too hard to be mixed with water and air. This results in a problem that results in ineffective treatment of the treated water.

Nitrogen bacteria such as Nitrobactor or Nitrosomonas immobilized by the above method are administered to the nitrification tank 5 to remove ammonia from the treated water by converting ammonia into nitrate nitrogen.

The present invention is intended to remove ammonia nitrogen, phosphorus, solids and nitrogen through the reaction tank in the salping bar and waste water, particularly wastewater containing high concentrations of organic matter such as livestock wastewater, manure, leachate, nitrogen, phosphorus, etc. In the organic acid tank and the methane fermentation tank, organic matters are removed, and ammonia is removed by converting ammonia nitrogen into nitrate nitrogen or nitrite nitrogen in the nitrification tank, and nitrate nitrogen or nitrite nitrogen is removed from the denitrification tank. It can be confirmed that the invention is characterized by treating wastewater through the method of removing nitrogen by converting to.

As described above, the present invention can effectively treat wastewater containing high concentrations of organic matter, such as livestock wastewater, manure and leachate, nitrogen, phosphorus, etc., which can effectively protect nature and protect the ecosystem. It is obvious that this is a useful invention.

Claims (5)

In the method for treating wastewater containing high concentration of organic matter such as livestock wastewater, manure, leachate, nitrogen, phosphorus, etc., The wastewater supplied to the reactor is reacted with a catalyst mixed with magnesium and calcium to produce MgNH ₄ PO ₄ 6H ₂ O and Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ to produce ammonia nitrogen, phosphorus and solids. And wastewater is treated primarily by the removal of nitrogen, Treating the treated water secondly by promoting the removal of organic matter in the methane fermentation tank filled with the organic acid tank and methane-producing bacteria in the first treated water, Treating the treated water in a third step by removing the ammonia by converting the ammonia nitrogen into nitrate nitrogen or nitrite nitrogen in a nitrification tank filled with the second treated water; Livestock wastewater, leachate and the waste water characterized in that the treatment of the waste water by removing the nitrogen by converting the nitrate nitrogen or nitrite nitrogen into nitrogen gas in the denitration reaction tank filled with the sulfided denitrification microorganisms Waste water collection methods such as manure. The method according to claim 1, Wastewater treatment method, such as livestock wastewater, leachate and manure, characterized in that for maintaining the wastewater at pH 8 or more in the reactor. The method according to claim 1, Livestock wastewater, leachate and manure treatment method characterized in that the interior of the reaction tank is built in a compartment of a rubber material and a stainless steel mesh therein. The method according to claim 1, Livestock wastewater, such as livestock wastewater, leachate and manure, characterized in that to increase the flow rate of the treated water transferred to the methane fermentation tank to increase the contact area and time with the methane-producing bacteria. The method according to claim 1, Livestock wastewater, leachate and manure waste treatment method, characterized in that the nitrification tank is composed of the upper and lower, the narrow and the central portion of the middle light and down.

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