KR20180128107A - Anaerobic sewage process with sulfide removal apparatus and method in its effluent - Google Patents

Abstract

The present invention provides an anaerobic sewage treatment method to solve an adverse effect on the treated water of residual sulfide in membrane filtration water which is an anaerobic membrane bioreactor (AnMBR) permeate water. The anaerobic sewage treatment method comprises: a step of precipitating and removing solids contained in wastewater (step 1); a step of decomposing the organic matter contained in the wastewater having undergone the step 1 into methane and carbon dioxide using an anaerobic microorganism (step 2); and a step of recovering the sulfide contained in the treated water through step 2 (Step 3).

Description

TECHNICAL FIELD The present invention relates to an anaerobic sewage treatment apparatus and method,

The present invention relates to a method and apparatus for removing sulfides in treated water from an anaerobic sewage treatment process.

Generally, the waste water treatment apparatus removes organic substances and suspended substances in the waste water and wastewater using the principle of coagulation and sedimentation. These water treatment devices have been widely used to purify industrial wastewater, animal wastewater, domestic sewage, and the like.

However, the conventional water treatment apparatus has discharged stable treated water only when a large sedimentation area and a long agglutination time are satisfied. Thus, when these conditions were not met, there was a tendency to rely on excessive drug administration and specialty medicines to obtain stable treatment water. As a result, there has been a problem in that the costs of chemicals and sludge are increased, which is unpreventable and ineffective.

On the other hand, the bioreactor for waste water treatment is divided into a dispersion growth reactor and an attached biofilm reactor. Biomass (or microorganisms) are mostly present in the suspended floc state in a dispersion growth reactor such as a standard activated sludge process. In order to reduce the volume of the reactor, the concentration of the biomass must be kept high. For this purpose, in a dispersion growth reactor such as a standard activated sludge method, a settling tank for transporting biomass is generally installed. This type of reactor is generally not used for anaerobic processes for municipal sewage and low concentration wastewater treatment due to the relatively short solids retention time.

On the other hand, the biofilm reactor is suitable for efficient anaerobic treatment requiring long solids retention time because biomass can be maintained at a high concentration by attaching biomass to media (media). These reactors include a packed bed reactor using a fixed filter medium and a fluidized bed reactor using a floating filter medium.

In a fluidized bed reactor, an appropriate flow rate of upflow flows through the media material layer of the particles, such as sand or granular activated carbon, allowing the media material to float on the fluid. Here, the downward force due to the gravity and the upward flow around the filter material are balanced. Fluidized bed reactors have been applied to remove nitrate and perchlorate from wastewater in particular. In the fluidized bed reactor, the high biomass concentration is maintained through the thick biofilm formed in the filter media. Therefore, the hydraulic residence time of the other type of reactor is required in the time series, Treatment efficiency can be obtained.

Korean Patent Laid-Open Publication No. 10-2011-0113480

Sulfur oxides present in wastewater are reduced by sulfate reducing bacteria in the anaerobic state and exist as sulfides of H ₂ S / HS ^- / S ^{2 -} form. In addition, it forms colloidal metal sulfides by combining with wastewater and metal cathodes Ca ^{2 +} and Mg ^{2 +} , which are commonly found in natural waters.

Formed metal sulfide is initially formed in a nano-scale, but growing more and size over time, in particular, the size of the particles the pH is higher the more formation there is increases as the pH is relative partial pressure of CO ₂ generated in the anaerobic reaction vessel However, in the case of effluent discharged out of the anaerobic tank, the CO ₂ is degassed while being exposed to the atmosphere, and as the pH increases, it can be observed with the naked eye.

In particular, in the case of an anaerobic membrane bioreactor (AnMBR), the metal sulfide formed is permeated through a membrane, causing turbidity upon exposure to the atmosphere, forming accumulation and scale on the tube, It has an unfavorable effect and causes odor.

In the case of such a metal sulfide, contact with oxygen in the air can be removed by the sulfated microorganism, but a long time or energy is required.

An anaerobic sewage treatment apparatus and an anaerobic sewage treatment method according to an embodiment of the present invention include a step (step 1) of precipitating solid matter contained in wastewater; Decomposing the organic matter contained in the wastewater having undergone the step 1 into methane and carbon dioxide using an anaerobic microorganism (step 2); Recovering the sulfide contained in the treated water through Step 2 (Step 3); And an anaerobic sewage treatment method.

A sedimentation tank for precipitating and removing solid matter contained in wastewater; An anaerobic tank for decomposing the organic matter contained in the wastewater discharged from the settling tank into methane and carbon dioxide using anaerobic microorganisms; A sulphide removal tank for recovering the sulphide contained in the treated water of the anaerobic reactor; And an anaerobic sewage treatment apparatus.

The anaerobic sewage treatment apparatus and the anaerobic sewage treatment method according to the embodiment of the present invention can effectively remove the sulfide by solving the adverse effect of the residual sulfide of the membrane filtration water which is the permeate water of the anaerobic membrane bioreactor.

In addition, 99% of phosphorus (P) remaining in the treatment water can be removed together with the sulfide.

1 is a schematic diagram of an anaerobic sewage treatment apparatus according to an embodiment of the present invention.
2 is a schematic view of an anaerobic sewage treatment apparatus according to another embodiment of the present invention.
3 is a schematic view of an anaerobic sewage treatment apparatus according to another embodiment of the present invention.
4 is a schematic diagram of an anaerobic sewage treatment apparatus according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings may be exaggerated for clarity of description, and the elements denoted by the same reference numerals in the drawings are the same elements. In the drawings, like reference numerals are used throughout the drawings. In addition, "including" an element throughout the specification does not exclude other elements unless specifically stated to the contrary.

Anaerobic sewage treatment method

Hereinafter, the anaerobic sewage treatment apparatus and anaerobic sewage treatment method will be described.

Anaerobic Membrane Bioreactor (ANMBR) is a wastewater treatment technology that operates using a membrane bioreactor (MBR). The sewage is filtered and separated into effluent and sludge, which is anaerobically treated by mesophilic bacteria that release methane as a by-product.

 An anaerobic membrane bioreactor (AnMBR) can be a sustainable alternative to sewage treatment because the energy generated by methane combustion can exceed the energy required to maintain the process.

The anaerobic sewage treatment method according to an embodiment of the present invention can combine the anaerobic membrane bioreactor with the method for removing sulfide to effectively separate the colloidal sulfide in the effluent of the anaerobic membrane bioreactor.

An anaerobic membrane bioreactor (AnMBR) has an advantage of obtaining excellent water quality. However, the metal sulfide thus formed is permeated through a membrane, causing turbidity when exposed to the atmosphere, , Forming a scale, aesthetically affecting the treated water adversely and causing odor. In addition, when it comes into contact with oxygen in the air, it can be removed by sulfated microorganisms, but it takes a long time or a lot of energy.

Therefore, in the embodiment of the present invention, a cohesive precipitation process or an ion exchange resin process may be connected to the rear end of the AnMBR in order to remove sulfide.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described with reference to the drawings.

1 is a schematic diagram of an anaerobic sewage treatment apparatus according to an embodiment of the present invention.

An anaerobic sewage treatment apparatus and an anaerobic sewage treatment method according to an embodiment of the present invention include steps of precipitating and removing solid matters contained in wastewater (step 1); Decomposing the organic matter contained in the wastewater having undergone the step 1 into methane and carbon dioxide using an anaerobic microorganism (step 2); Recovering the sulfide contained in the treated water through Step 2 (Step 3); . Hereinafter, description will be made on the basis of Fig.

As shown in FIG. 1, an anaerobic sewage treatment apparatus according to an embodiment of the present invention includes a sedimentation tank 100, an anaerobic tank 200, and a sulphide removal tank 300.

In the step (step 1) of precipitating solids contained in the wastewater, the wastewater may be high-concentration wastewater or municipal wastewater and low-concentration wastewater, and the present invention is not particularly limited thereto. In the step 1, the sediment contained in the wastewater can be precipitated and removed by using the settling tank (100).

The sedimentation tank 100 removes Suspended Solids (SS) in the incoming sewage and low concentration wastewater and removes biological oxygen demand (BOD) or chemical oxygen demand (COD) Oxygen Demand) can be removed together to reduce the post-treatment process load and increase the treatment efficiency. The sedimentation tank 100 removes suspended solids by gravity sedimentation through the initial sedimentation facility, which can perform functions such as reducing the load of the biological treatment process, reducing the facility capacity of the subsequent treatment facility, and stably reducing the operation cost have. In addition, the inflowing municipal sewage and the low-concentration wastewater can settle for finer fine particles in the sewage while staying for several hours. In the sedimentation tank 100, suspended matters floating on the surface can be removed using a scraper.

The settling tank 100 is divided into an inlet portion, a settling portion, a sludge storage portion, and an outlet portion. In the inflow portion, the lower force is dispersed, and in the precipitation portion, the precipitate is precipitated.

At this time, the precipitated precipitate is referred to as a primary sludge and is sent to a thickener 500 of a sludge treatment process to be described later to undergo a sludge treatment process. Sewage treated in the settling tank 100 is discharged from the anaerobic tank 200 ) And can be processed through biological processing.

Typically, in the settling tank 100, approximately 30% of the biological oxygen demand is removed while the sewage is staying for about 2 to 3 hours, and about 35% of the suspended substances can be removed. The sedimentation efficiency depends on the type of sewage network, the period of sewage production, and the degree of crushing prior to sedimentation. The settling tank 100 can perform a function of appropriately discharging the sludge accumulated in the water quality management to smooth the function of the subsequent process.

The sedimentation tank 100 may use a mechanical solids separation device such as a coagulation sedimentation tank or a centrifugal separator using a flocculant to reduce the load of the anaerobic tank 200 that increases the removal efficiency of the suspended solids, The invention is not particularly limited.

In step 2, the organic matter contained in the wastewater passed through step 1 is decomposed into methane and carbon dioxide using anaerobic microorganisms. The step 2 may be performed using the anaerobic tank 200.

The anaerobic reactor 200 can decompose organic matter in sewage water into methane and carbon dioxide by using the anaerobic microorganisms in the sedimentation tank 100.

Examples of the anaerobic reactor 200 include anaerobic bacteria reactor (AFR), anaerobic fluidized bed reactor (AFBR), anaerobic filter (AF), upflow anaerobic sludge blanket (UASB), anaerobic membrane bioreactor (ANMBR), continuous storaged tank reactor (CSTR) , Anaerobic Expanded Granular Sludge Blanket Reactor, Anaerobic Internal Circulation Bioreactor, ASBR (Anaerobic Sequencing Batch Reactor), AFMBR (Anaerobic Fluidized Membrane Bioreactor), etc. Also, a hybrid reaction tank or the like may be used, Is not particularly limited thereto.

The step (step 3) of recovering the sulfide contained in the treated water after the step 2 may proceed in the sulfide removing tank 300.

 Referring to FIG. 1, in the sulfide recovery process according to the present embodiment, the sulfide dissolved in the effluent discharged from the anaerobic tank 200 can be recovered in the sulfide removal tank 300.

The sulfide dissolved in the effluent discharged from the anaerobic reactor 200 is reduced by sulfate reducing bacteria in an anaerobic state and exists as a sulfide of H ₂ S / HS ^- / S ² -form. In addition, it forms colloidal metal sulfides by combining with wastewater and metal cathodes Ca ^{2 +} and Mg ^{2 +} , which are commonly found in natural waters.

Formed metal sulfide is initially formed in a nano-scale, but growing more and size over time, in particular, the size of the particles the pH is higher the more formation there is increases as the pH is relative partial pressure of CO ₂ generated in the anaerobic reaction vessel However, in the case of effluent discharged out of the anaerobic tank, the CO ₂ is degassed while being exposed to the atmosphere, and as the pH increases, it can be observed with the naked eye.

The sulfide removing tank 300 is connected to one side of the anaerobic tank 200 so that the sulfide can be recovered. The phosphorus (P) may be removed together when the sulfide is recovered.

The method of recovering the sulfide in the step 3 may be an anaerobic sewage treatment method by coagulation sedimentation method. The flocculation and sedimentation method may include all the steps of transforming the zeta potential into an unstable state.

In the case of fine particles or colloids, as the absolute value of the Zeta potential obtained experimentally increases, the repulsive force between the particles increases and the stability of the particles increases. On the other hand, when the zeta potential approaches zero, the particles tend to flocculate. Thus, the zeta potential can be used as a measure of the dispersion stability of the colloidal particles

The coagulation and sedimentation method may consist of rapid stirring, slow stirring and precipitation, and the rapid stirring may be performed using an impeller or a static mixer.

The coagulation process is a process for precipitating and removing colloidal substances or fine particles, and it is necessary to stir the coagulant to make the collision between the coagulant and the wastewater to be increased, and to stir rapidly for uniform dispersion and to form a floc.

The purpose of the rapid stirring is to cause a lot of collision between the flocculant and the particles in the sewage, to achieve uniform dispersion, and the purpose of the slow stirring is to form a large flocculable precipitate by agglomeration of the floc produced by the rapid stirring have. The method of the slow stirring may be a method using a paddle type or a turbine type slow speed stirrer.

The sedimentation step of the coagulation sedimentation method may be a process of sinking and physically removing suspended matters. If sedimentation occurs only without coagulation and flocculation reaction, there may be a problem that only a large amount of suspended particles are removed.

The coagulated sedimentation method is a method for removing colloidal particles by adding a charge opposite to that of the colloid particles or by causing a pH change to reduce the zeta potential so as to form a floc, At this time, the larger the ionization value of the coagulant, the opposite charge substance, the greater the coagulation effect.

The flocculation process of the coagulation sedimentation method may be a process of aggregating fine particles by adding a flocculant to form indefinite flocs, and growing the flocculent flocculent by addition of coagulant aid to improve and eliminate precipitability. In this case, after the coagulant is added to the sewage, rapid stirring may be performed to promote the reaction of the coagulant and the fine particles in the sewage, followed by slow stirring to form a flock.

In the anaerobic sewage treatment method according to an embodiment of the present invention, the raw water is dewatered in the rapid stirring tank, the flocculant is supplied to the rapid stirring tank, and the sludge is agglomerated through the flocculant to purify the water.

The impeller is formed to rotate and can act to forcefully stir the introduced additive and the wastewater. The static mixer may be agitated and mixed while moving the fluid sequentially.

The coagulant used in the settling tank 100 may be an aluminum sulfate (Al ₂ (SO ₄ ) ₃ 14H ₂ O), ferrous sulfate (FeSO ₄ 7H ₂ O) ferric sulfate _{(Fe (SO 4) 3 9H} 2 O), polyaluminum chloride (PAC, poly aluminum chloride), poly aluminum sulphate (poly aluminum sulfate, PAS), poly-aluminum sulfate silicate (poly aluminum sulfate silicate, PASS) , Polyaluminum chloride (PACS), starch, glue, polyethyleneimine, polyacrylamide, sodium polyacrylate and the like can be applied. Preferably, an aluminum-based coagulant which does not cause chromaticity can be applied have. The present invention is not particularly limited thereto.

Among the above flocculants, aluminum sulfate is treated in such a manner that it directly bonds with water in water or binds to OH ions in water, and is then adsorbed and removed from the sulfide or phosphorus (P) in water. In order to react with aluminum sulfate, sufficient alkalinity should be supplied, and in the case of lack of alkalinity, it may be necessary to supply alkalinity using calcium hydroxide. The pH titration range is about 6.5 to 8, in which case additional alkalinity replenishment may be unnecessary. Aluminum sulphate is less expensive than other flocculants and is effective for removal of almost all suspended substances or suspended matters such as turbidity, color, and algae, and can be injected in large quantity because there is no toxicity. In addition, the crystals are easy to handle because they are not corrosive and have the advantage of not spoiling the facilities like iron salts.

The above-mentioned coagulant such as aluminum sulfate has a wide range of cohesion with respect to pH or turbidity, is excellent in cohesive force, does not consume much alkalinity, and preferably suppresses the occurrence of degradation.

In order to form an optimum flocculation state by using a coagulant and a coagulant, it is possible to reduce the amount of flocculant used in combination. Coagulant adjuvants can be divided into inorganic agents and organic agents. When using acidic aluminum or iron salts, it is necessary to add sodium hydroxide or lime to prevent the pH from dropping relatively.

The coagulation aid used in the flocculation and sedimentation method is a cationic polymer, calcium hydroxide (Ca (OH) ₂ ), calcium oxide (CaO), aluminum nitride (Na ₂ Al ₂ O ₄ ) , Bentonite (Clay), calcium carbonate (CaCO ₃ ), and anionic polymer, and the present invention is not particularly limited thereto.

The positively charged monomers in the polymer are called cationic polymers, the negatively charged monomers are called anionic polymers and the polymer with a total charge close to zero is called a nonionic polymer . Cationic polymers have the ability to adsorb and neutralize negatively charged particles.

As the coagulation assistant for use in the flocculation and sedimentation method, a cationic polymer may be preferably used to effectively remove a negatively charged sulfide.

The amount of the flocculant to be injected may be an injection concentration of 10 ppm to 30 ppm in the case of AnMBR. When the amount of the coagulant is 50 ppm or more and the pH is decreased to 6 or less, it is difficult to form stable floc of the metal sulfide.

When the amount of the flocculant is less than 10 ppm, the amount of the flocculant is insufficient to remove the sulfur (S) and phosphorus (P) normally present without supplementing the alkali. When the flocculant is added in an amount exceeding 30 ppm, There is a problem that it is difficult to form flocculent floc.

In the anaerobic sewage treatment method according to another embodiment of the present invention, the method for recovering the sulfide in the step 3 may be a method by an ion exchange resin method.

When the method of recovering the sulfide in the step 3 is a method using an ion exchange resin method, it may include ion-binding using an artificial resin or a natural resin.

An ion exchange resin is a polymer substance that exchanges and purifies ionic impurities dissolved in a polar and nonpolar solution, which is obtained by bonding an ion exchanger to a polymer having a fine three-dimensional structure. But the present invention is not particularly limited thereto.

The artificial resin includes a synthetic polymer, and the natural resin may include natural effluents such as rosin, corpus, and animal effluents such as shellac and casein.

Among the odor components, those having an anionic group and a cationic group can be captured and deodorized by an ion exchange resin. At this time, the deodorization mechanism can be attributed to the ion adsorption and the physical adsorption due to the porosity of the resin surface. When the ion-adsorbing ability of the ion-exchange resin is lowered, it can be regenerated and used repeatedly as a regenerant such as a soda solution, a hydrochloric acid solution and a sodium chloride (NaCl) solution.

The anaerobic sewage treatment method according to another embodiment of the present invention may further include the step of recovering methane dissolved in the effluent discharged through the step 3 after the step 3.

Further, in the anaerobic sewage treatment method further comprising the step of recovering methane dissolved in the effluent discharged through the step 3 after the step 3, the step 3 may be carried out in a closed state so as to prevent the loss of dissolved methane Lt; / RTI > The following description is based on Fig.

2 is a schematic view of an anaerobic sewage treatment apparatus according to another embodiment of the present invention.

2, the anaerobic sewage treatment apparatus according to another embodiment of the present invention may include a sedimentation tank 100, an anaerobic tank 200, a sulphide removal tank 300, and a dissolved methane recovery tank 400 have. After step 3, the step of recovering the methane dissolved in the effluent discharged through step 3 may be performed in the dissolved methane recovery tank 400.

The sedimentation tank 100, the anaerobic tank 200, and the sulphide removal tank 300 have the same structure and function as those of the anaerobic sewage treatment apparatus according to the embodiment of the present invention described above, Hereinafter, the dissolved methane recovery tank 400 will be described.

Referring to FIG. 2, in the methane recovery process according to the present embodiment, methane dissolved in the effluent discharged from the anaerobic reactor 200 can be recovered from the dissolved methane recovery vessel 400.

Methane present in the gaseous phase in the anaerobic process exists in dissolved state in the effluent according to Henry's law. When the low concentration wastewater is treated in a short residence time, the gas produced in the solution is not sufficiently separated and saturation or supersaturation and may be discharged together with the effluent in an oversaturation state. The dissolved methane contained in the effluent escapes into the atmosphere to form an equilibrium when it comes into contact with air. Methane is a 28 to 36 times higher global warming potential (GWP) than carbon dioxide, which has an adverse effect on global warming. . In an anaerobic process for treating low-concentration wastewater, 40% to 60% of the methane generated is released in the form of dissolved methane. Therefore, the recovery process is very important for energy independence in order to improve energy recovery efficiency.

The dissolved methane recovery tank 400 may be connected to one side of the sulphide removal tank 300 to recover methane dissolved in the effluent discharged from the anaerobic tank 200.

The method for removing or recovering dissolved methane present in the treated water of the anaerobic digestion process of the present invention may be biological oxidization, aeration, air degassing, separation membrane, or the like, and the present invention is not particularly limited thereto.

The apparatus for anaerobic sewage treatment according to another embodiment of the present invention further includes a step of concentrating the sludge precipitated in step 1 and a step of heating and stirring the concentrated sludge to decompose the organic matter of the sludge into byproducts and methane gas can do. 3 will be described below.

3 is a schematic view of an anaerobic sewage treatment apparatus according to another embodiment of the present invention.

3, the anaerobic sewage treatment apparatus according to another embodiment of the present invention includes a sedimentation tank 100, an anaerobic tank 200, a sulphide removal tank 300, a thickener 500, a sludge digester 600, , And a generator (700).

The step of concentrating the precipitated sludge in the step 1 may be performed in the thickener 500.

The concentration tank 500 can perform solid-liquid separation of the primary sludge that has been generated in the sedimentation tank 100, thereby increasing the concentration and reducing the sludge volume. At this time, the sludge can be concentrated by precipitation by gravity.

Since the primary sludge is an inevitable by-product from the sewage treatment process, the sludge must be minimized in the sewage treatment plant, and the concentration of the sludge in the sludge tank 500 can be reduced by 97% to 99.2%. At this time, the sludge concentration situation not only has a great influence on the overall effect of the sludge treatment facility, but also requires a sufficient management because the separated liquid affects the sewage treatment facility.

The concentrated sludge in the concentration tank 500 may be sent to the sludge digestion tank 600.

The step of heating and stirring the concentrated sludge to decompose the organic matter of the sludge into by-products and methane gas may be performed in the sludge digestion tank 600.

The sludge digestion tank 600 chemically processes the concentrated sludge. By heating and stirring the sludge in the closed tank, the organic matter of the sludge is decomposed to generate methane gas and byproducts.

The sludge digestion tank 600 may be an aerobic digester or an anaerobic digestion tank for treating sludge by decomposing organic matter by the action of microorganisms. At this time, the aerobic digester is easy to operate, has almost no odor, and has a low biological oxygen demand and low concentration of suspended substances.

Further, the anaerobic digestion tank is advantageous in that the anaerobic digestion tank does not require a power facility, can be continuously treated, can be easily maintained, obtain useful methane gas, and can kill pathogens and parasites. The methane gas generated in the anaerobic digester may be used as its own fuel (generator 700) to help recycle resources.

The sludge digestion tank 600 mainly uses an anaerobic digestion method which is a method of treating sludge by blocking oxygen, and it can reduce the content of organic matter and can minimize and stabilize secondary pollution after death.

Anaerobic digestion of the sludge through the anaerobic digestion tank not only can reduce the sludge but also improves the dewaterability of the sludge, creates a sanitary sludge and uses the generated digested gas as fuel.

The sludge in the sludge digestion tank 600 may be sent to a dehydrating tank (not shown) to lower the water content and then be incinerated, dried, recycled, or buried. The sludge generated as a result of sewage treatment usually has a large volume and a large amount of water, so it is almost impossible to dispose of the sludge as it is liquid. Therefore, by using a sludge dewatering system such as a pressure filter combined with filtration and compression, it is possible to reduce the sludge capacity by dewatering into a cake phase having a sludge water content of about 80% or less, thereby facilitating the removal, transportation and disposal.

Another embodiment of the present invention may be an anaerobic sewage treatment method further comprising the step of removing nitrogen of the treated water after the step 2, prior to the step 3. Hereinafter, description will be made on the basis of Fig.

4 is a schematic view of an anaerobic sewage treatment apparatus according to another embodiment of the present invention.

Referring to FIG. 4, the nitrogen removal device 800 may be connected to the anaerobic tank 200 to remove nitrogen from the treated water.

Before the step 3, the step of removing nitrogen from the treated water through the step 2 may be performed in the nitrogen removing apparatus 800.

The nitrogen removal apparatus 800 may be installed to adjust the concentration of nitrogen in the effluent discharged as final treatment to the discharge water quality standard. Urban sewage and low concentration wastewater contain not only organic matter but also nutrient salts including nitrogen and phosphorus. Nutrients are inorganic elements necessary for growth and proliferation of microorganisms causing degradation of organic matter. Among them, nitrogen compounds and phosphates are the elements that must be continuously supplied for biological cell formation and energy metabolism. However, when nutrients such as nitrogen (N) or phosphorus (P) are increased, ecosystem balance is destroyed and eutrophication phenomenon occurs. Nitrogen sources that cause such eutrophication include domestic sewage, factory wastewater, and agricultural wastewater. Living sewage contains proteins, peptides, amino acids and urea as organic nitrogen compounds, and contains a small amount of ammonia as an inorganic nitrogen compound. The form of organic nitrogen compounds or nitrogen is oxidized into nitrite or nitrate by the action of microorganisms in water and consumes oxygen in water. Nitrite or ammonia has a devastating effect on fish.

When nitrogen (N) accumulates in the reservoir, the problem of eutrophication occurs. Eutrophication is a phenomenon in which when nitrogen or phosphorus is introduced into water bodies such as reservoirs, microorganisms that feed on these nitrogen or phosphorus begin to overproduce. Therefore, in order to fundamentally prevent eutrophication, the nutrient components in the wastewater must be removed before entering the river or other waters.

In the present embodiment, the nitrogen removal device 800 for removing nitrogen (N) contained in the effluent discharged from the wastewater by decomposition of the organic material is additionally provided, so that the concentration of nitrogen can be adjusted to the discharged water quality standard have.

Anaerobic sewage treatment plant

An anaerobic sewage treatment apparatus according to an embodiment of the present invention includes a sedimentation tank for precipitating and removing solid matter contained in wastewater; An anaerobic tank for decomposing the organic matter contained in the wastewater discharged from the settling tank into methane and carbon dioxide using anaerobic microorganisms; A sulphide removal tank for recovering the sulphide contained in the treated water of the anaerobic reactor; .

An anaerobic sewage treatment apparatus according to another embodiment of the present invention includes a sedimentation tank for sedimenting and removing solid matter contained in wastewater; An anaerobic tank for decomposing the organic matter contained in the wastewater discharged from the settling tank into methane and carbon dioxide using anaerobic microorganisms; A sulphide removal tank for recovering the sulphide contained in the treated water of the anaerobic reactor; A dissolved methane recovery tank for recovering dissolved methane contained in the treated water of the anaerobic reactor; .

An anaerobic sewage treatment apparatus according to another embodiment of the present invention includes a sedimentation tank for sedimenting and removing solid matter contained in wastewater; An anaerobic tank for decomposing the organic matter contained in the wastewater discharged from the settling tank into methane and carbon dioxide using anaerobic microorganisms; A sulphide removal tank for recovering the sulphide contained in the treated water of the anaerobic reactor; A concentrating tank for increasing the concentration and reducing the sludge volume by solid-liquid separation of the primary sludge settled in the settling tank; A sludge digester for chemical treatment of concentrated sludge; generator; .

An anaerobic sewage treatment apparatus according to another embodiment of the present invention includes a sedimentation tank for sedimenting and removing solid matter contained in wastewater; An anaerobic tank for decomposing the organic matter contained in the wastewater discharged from the settling tank into methane and carbon dioxide using anaerobic microorganisms; A nitrogen removal device; A sulphide removal tank for recovering the sulphide contained in the treated water of the anaerobic reactor; .

The settling tank, the reaction tank, the sulphide removal tank; The dissolved methane recovery tank, the concentration tank, the sludge digestion tank, the nitrogen removal unit, and the like are the same as those described above, and a description thereof will be omitted.

The present invention is not limited to the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

100: settling tank
200: anaerobic tank
300: Sulfide removal tank
400: dissolved methane recovery tank
500: Enrichment tank
600: sludge digester
700: generator
800: nitrogen removal device

Claims (13)

Precipitating the solid contained in the wastewater (step 1);
Decomposing the organic matter contained in the wastewater having undergone the step 1 into methane and carbon dioxide using an anaerobic microorganism (step 2); And
Recovering the sulfide contained in the treated water through Step 2 (Step 3); ≪ / RTI >
The method according to claim 1,
Further comprising the step of recovering methane dissolved in the effluent discharged through the step 3 after the step 3.
3. The method of claim 2,
Wherein the step (3) is carried out in an enclosed atmosphere to prevent the loss of dissolved methane.
The method according to claim 1,
The step 3 is an anaerobic sewage treatment method according to the coagulation sedimentation method.
5. The method of claim 4,
Wherein the coagulation sedimentation method comprises a step of transforming the zeta potential to an unstable state.
5. The method of claim 4,
The flocculant used in the flocculation and precipitation method is an aluminum (Al) -based anaerobic sewage treatment method.
5. The method of claim 4,
Wherein the coagulation aid used in the flocculation and sedimentation method is a cationic polymer.
The method of claim 4, wherein the flocculation and sedimentation method comprises a rapid stirring step, a slow stirring step, and a precipitation step.
The method according to claim 1,
The step 3 is an anaerobic sewage treatment method using an ion exchange resin method.
10. The method of claim 9,
Wherein the ion exchange resin method comprises ion-binding using an artificial resin or a natural resin.
The method according to claim 1,
Further comprising the steps of: concentrating the sludge precipitated in step 1; and heating and stirring the concentrated sludge to decompose the organic matter of the sludge into by-products and methane gas.
The method according to claim 1,
Further comprising the step of removing nitrogen in the treated water after the step 2 before the step 3.
A sedimentation tank for precipitating and removing solid matter contained in wastewater;
An anaerobic tank for decomposing the organic matter contained in the wastewater discharged from the settling tank into methane and carbon dioxide using anaerobic microorganisms; And
A sulphide removal tank for recovering the sulphide contained in the treated water of the anaerobic reactor; Wherein the anaerobic sewage treatment apparatus comprises:

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