KR102398075B1 - Up-flow bioelectrochemical apparatus and method for advanced wastewater treatment - Google Patents

Abstract

In the upflow bioelectrochemical device of the present invention, an insulated electrode coated with a dielectric material is vertically installed in a bioelectrochemical ultra-high-level processing reactor, a conductive medium is injected between the electrodes, and the electrode is polarized with an external power supply to generate an electric field. It is characterized by dominant growth of electroactive bacteria and promoting electron transfer between the electroactive bacteria by forming them. Therefore, by using the upflow bioelectrochemical device of the present invention, it is possible to treat wastewater and secondary treated wastewater in an ultra-advanced manner.

Description

Up-flow bioelectrochemical apparatus and method for advanced wastewater treatment

The present invention relates to an upflow bioelectrochemical device for ultra-advanced treatment of wastewater. Specifically, the conductive medium in the form of particles is filled inside an upflow reactor equipped with an insulating electrode coated with a dielectric material and polarized by applying a small voltage to the electrode. It relates to an upflow type bioelectrochemical device and method that can effectively treat wastewater and secondary treated water from a wastewater treatment facility in an anaerobic state in an anaerobic state by a method of predominantly growing active bacteria and facilitating the transfer of electrons between them.

Sewage wastewater generally contains various pollutants such as biodegradable organic matter, suspended matter, and nitrogen compounds. go crazy In order to solve the above problems, so far, wastewater has been treated using advanced treatment processes consisting of various combinations of anaerobic tanks, anoxic tanks and aerobic tanks. However, the water quality of the effluent discharged from the existing wastewater treatment facilities is very unstable in connection with the fluctuations of the inflow water quality and flow rate. . Therefore, improving the water quality of the effluent discharged from the wastewater treatment facility and stabilizing it by alleviating water quality variability is a very important issue in the environmental management of the water system. To this end, it is often considered to replace the bioreactor of a wastewater treatment facility with a membrane bioreactor that can significantly increase the amount of microorganisms, or to install additional physicochemical advanced treatment processes such as activated carbon adsorption and ion exchange. However, when a membrane bioreactor is introduced into an existing wastewater treatment facility, a large amount of cost is required for installation and maintenance of the facility, and there is a limit to further improving the water quality of treated water only with the increased amount of microorganisms in the bioreactor. In addition, since the concentration of contaminants in the wastewater after secondary treatment is too low for microorganisms to metabolize and grow effectively, biological ultra-high-level treatment is thermodynamically disadvantageous. It is difficult to do.

In general, pollutants contained in wastewater are biologically treated by allowing activated sludge microorganisms composed of various bacteria to metabolize and grow using the pollutants as substrates. When looking at the growth kinetics of microorganisms related to the decomposition of contaminants in this biological treatment process using the Monod equation of Equation (1), it is the zero-order equation for the substrate concentration when the substrate concentration is high, and 1 for the substrate concentration when the substrate concentration is low. follow the formula

Here, μ is the specific growth rate of the microorganism, and μ _m is the maximum specific growth rate. K _s is the half-saturation rate constant, and S is the substrate concentration. Therefore, the growth kinetics of microorganisms at high substrate concentration is determined by the maximum specific growth rate of microorganisms and is independent of substrate concentration. In contrast, the growth kinetics of microorganisms at low substrate concentrations is mainly limited by the substrate concentration, and the main parameter influencing the growth of microorganisms is the half-saturation rate constant. Here, the reciprocal of the half-saturation rate constant is generally called substrate affinity. In most biological wastewater treatment processes in a fully mixed bioreactor, the growth of microorganisms is greatly limited by the low substrate concentration because the concentration of the substrate in the bioreactor is the same as that of the effluent. Therefore, biological treatment of wastewater is relatively advantageous when the substrate affinity (low Ks) of microorganisms is high. In order for microorganisms to metabolize and grow pollutants in the biological treatment process of wastewater, electron donors, such as substrates, and electron acceptors, such as oxygen, must first move from the bulk solution in the bioreactor to the microbial flocs by physical advection. It must diffuse from the microbial floe back to the surface of the microbial cells and be absorbed by the microorganisms. Therefore, the value of the half-saturation rate constant is determined by physical factors such as movement and diffusion of substrates used by microorganisms in a bioreactor, absorption through cell membranes of microorganisms, and biological factors such as biochemical reactions that metabolize substrates. In general, agitation is a physical method to improve substrate affinity of microorganisms by accelerating movement by advection of substrates in bulk solution and reducing the size of microbial flocs, thereby reducing the distance required for substrate diffusion. Biological methods for improving substrate affinity include using a microbial species with excellent substrate absorption or accelerating substrate metabolism. However, if the bioelectrochemical method is used, the metabolic process of the substrate can be greatly accelerated. To do this, first, an electric field must be formed in the bulk solution between the electrodes by installing an electrode in the bioreactor and applying a voltage using a DC power supply. Under an electric field, microorganisms express electroactive genes that enable direct exchange of electrons with the outside of the microbial cell through cofactors such as cytochrome type C or conductive pili. Microorganisms in which electroactive genes are expressed can be roughly classified into exoelectrogens and electrotrophs, and are called electroactive microorganisms.

Electroactive bacteria can transfer electrons using direct interspecies electron transfer through direct physical contact with each other or mediated interspecies electron transfer mediated by abiotic redox substances. Efficient substrate metabolism is possible because the heterogeneous electron transfer is further enhanced under an electric field. The electroactive bacteria grow on the surface of the polarized electrode or the bulk solution of the anaerobic reactor exposed to an electric field. However, even in a general bioreactor without polarization electrodes, if conductive materials such as activated carbon, carbon nanotubes, and magnetite exist, electroactive bacteria can grow on their surfaces, and the conductive materials serve as a conduit to mediate electron transfer between species. do

On the other hand, in order to examine the effect of the metabolic process of microorganisms by heterogeneous electron transfer enhanced by an electric field on substrate affinity, the half-saturation rate constant is expressed as a function of the change in free energy as in Equation (2).

Here, ΔG ⁰ and ΔG are the changes in free energy between the standard state and the present state, and R and T are the ideal gas constant and absolute temperature, respectively. In Equation (2), when the amount of free energy change (ΔG) in the current state increases, the half-saturation rate constant (K _s ) value becomes small and the substrate affinity increases. able to metabolize the body. The amount of change in free energy in the redox reaction can be expressed as in Equation (3) below by combining the Nernst equation and the free energy equation.

Here, n is the number of moles of electrons transferred in the redox reaction, and F is the Faraday constant. In addition, E represents the polarization potential of the electrode or the strength of the electric field that affects the movement of electrons. The polarization potential of the electrodes installed in the bioreactor or the electric field between the electrodes changes the polarity of the reactant and the alignment of the permanent dipole, thereby affecting the enthalpy and entropy of the reaction system, thereby increasing the amount of free energy change. This means that contaminants in wastewater can be effectively removed to a lower concentration by improving the substrate affinity of microorganisms on the surface of the polarization electrode or in the solution exposed to an electric field. This thermodynamically demonstrates that contaminants can be more effectively removed even to low concentrations by installing a polarizing electrode in a bioreactor for wastewater treatment to form an electric field and injecting a conductive material that can act as an electron transport medium.

However, there has been no reported case of ultra-advanced treatment of wastewater by injecting a conductive medium into the bioreactor as above and creating an electric field.

The patents and references mentioned in this specification are hereby incorporated by reference to the same extent as if each publication were individually and expressly specified by reference.

Korean Patent Laid-Open Patent 10-2006-0119282

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The present invention is to solve the above problems by injecting a conductive medium in the form of particles into an upflow bioreactor and installing a polarizing electrode to form an electric field, thereby predominately growing electroactive bacteria between in vitro electron-emitting bacteria and electrontrophic bacteria. It relates to a bioelectrochemical device that enables ultra-high-level treatment of wastewater by increasing the substrate affinity of microorganisms by improving interspecies electron transfer.

An object of the present invention is a bioelectrochemical ultra-advanced treatment reactor in which wastewater is supplied in an upward flow by a porous influent distributor; two or more insulated electrodes positioned inside the bioelectrochemical ultra-high-level processing reactor and coated with a dielectric material; And to provide an upflow bioelectrochemical device for ultra-advanced treatment of wastewater including a conductive medium disposed between the two or more insulating electrodes, and a method for ultra-advanced treatment of wastewater using the same.

Other objects and technical features of the present invention are more specifically set forth by the following detailed description of the invention, claims and drawings.

The present invention relates to a bioelectrochemical ultra-advanced treatment tank in which wastewater is supplied in an upward flow by a porous influent distributor; two or more insulated electrodes positioned inside the bioelectrochemical ultra-high-level processing reactor and coated with a dielectric material; and a conductive medium disposed between the two or more insulating electrodes. It provides an upflow bioelectrochemical device for ultra-advanced treatment of wastewater comprising a.

The wastewater is characterized in that it is low-concentration wastewater or sewage treatment plant inflow water having a chemical oxygen demand (COD) of 40 mg/L or less or a total nitrogen (TN) concentration of 20 mg/L or less, and the formula for the initial operation of the bioelectrochemical device It is characterized in that activated sludge, anaerobic sludge, or a mixture thereof collected from a bioreactor of a wastewater treatment facility as a seed strain is used as a seed strain.

The present invention polarizes by applying a voltage so that an electric field of 0.2 to 3.3 V/cm is formed between the two or more insulating electrodes. It is characterized in that the carbon-based particulate material having high conductivity and high biocompatibility is filled as a conductive medium.

The present invention provides a first step of injecting seedling sludge into a bioelectrochemical ultra-advanced treatment tank;

a second step of supplying wastewater in an upflow manner to the bioelectrochemical ultra-advanced treatment tank to which the seedling sludge is supplied; and injecting a conductive medium into the bioelectrochemical ultra-advanced treatment tank supplied with the wastewater, installing two or more insulating electrodes coated with dielectric material, and then applying a voltage to the insulating electrodes to obtain a voltage of 0.2 to 3.3 V/cm between the electrodes. It provides a method for ultra-advanced treatment of wastewater using an upflow bioelectrochemical device comprising; a third step of polarizing to form an electric field.

In the upflow bioelectrochemical device for ultra-advanced treatment of wastewater according to the present invention, the conductive medium in the form of particles injected between insulating electrodes coated with dielectric material relieves the distance attenuation of the electric field strength formed in the bulk solution between the electrodes, and the inside of the reaction tank so that an electric field is evenly formed in the In addition, the electroactive bacteria attach and grow on the surface of the injected conductive medium, thereby increasing the biomass of the electroactive bacteria. Therefore, if the upflow bioelectrochemical device for ultra-advanced treatment of wastewater of the present invention is used, stable ultra-advanced treatment of wastewater and additional ultra-advanced treatment (tertiary treatment) of secondary treatment sewage treatment plant effluent thermodynamically impossible due to low substrate affinity ) is possible.

1 is a schematic diagram of an upflow bioelectrochemical device for ultra-advanced treatment of wastewater according to the present invention.
2 shows an insulating electrode and a conductive medium of the present invention.
Figure 3 shows the change in chemical oxygen demand (COD) according to the treatment time in the tertiary treatment Example 1 and Comparative Example 1 for model wastewater having the same physicochemical properties as the effluent from the secondary treatment wastewater treatment plant of the present invention; .
4 shows the change in total nitrogen (TN) concentration according to the treatment time of the tertiary treatment Example 1 and Comparative Example 1 for model wastewater having the same physicochemical properties as the effluent from the secondary treatment wastewater treatment plant of the present invention; .
Figure 5 shows the change in chemical oxygen demand (COD) according to the treatment time of the tertiary treatment Example 2 and Comparative Example 2 of the effluent from the secondary treatment wastewater treatment plant of the present invention.
6 shows the change in total nitrogen (TN) concentration according to the treatment time of Example 2 and Comparative Example 2 for the tertiary treatment of the effluent from the secondary treatment wastewater treatment plant of the present invention.
7 shows the change in chemical oxygen demand (COD) according to the treatment time of the ultra-advanced wastewater treatment Example 3 and Comparative Example 3 of the present invention.
Figure 8 shows the change in total nitrogen (TN) concentration according to the treatment time of the ultra-advanced wastewater treatment Example 3 and Comparative Example 3 of the present invention.

The present invention is a bioelectrochemical ultra-high-level processing reactor (10); a porous influent distributor 50 located under the bioelectrochemical ultra-advanced treatment tank 10; Insulated electrode pairs (21, 22) installed vertically inside the bioelectrochemical ultra-high-level processing reactor; and a conductive medium (60) disposed between the insulated electrode pairs (21, 22); It relates to an upflow bioelectrochemical device for ultra-advanced treatment of wastewater, characterized in that it comprises an external voltage source 30 for polarization by applying a voltage to the insulated electrode. Hereinafter, the bioelectrochemical ultra-advanced treatment tank may be used in combination with the bioelectrochemical ultra-advanced treatment tank.

In addition, by injecting the seeding sludge into the bioelectrochemical ultra-advanced treatment tank 10 and using the external voltage source 30 to polarize the insulating electrodes 21 and 22 to positive and negative poles, the electric field between the insulating electrodes 21 and 22 Forming and supplying the wastewater in an upflow manner to the bioelectrochemical ultra-advanced treatment tank 10 through the influent distributor 50 at the bottom so that the wastewater is ultra-highly treated while passing through the bioelectrochemical ultra-advanced treatment tank 10 A method of characterizing it is provided.

The electric field formed inside the bioelectrochemical ultra-advanced treatment tank 10 expresses the electroactive genes of some microorganisms present in the seeding sludge to change them into electroactive bacteria, and to grow them dominantly on the surface of the bulk solution and the conductive medium 60 Thus, it is characterized in that it effectively removes contaminants by electron transfer between species.

The role of the components of the up-flow bioelectrochemical device for ultra-advanced treatment of wastewater of the present invention and the ultra-advanced treatment method of wastewater of the present invention will be described in detail as follows.

In the up-flow bioelectrochemical device for ultra-advanced treatment of wastewater according to the present invention, since wastewater is supplied up-flow from the lower part of the bio-electrochemical ultra-advanced treatment tank 10, the solids sink by gravity and only purified fresh water flows to the top. is the structure This structure has the effect of improving and stabilizing the treatment efficiency of wastewater by preventing the outflow of the electroactive bacteria and the conductive medium 60 while continuously operating the bioelectrochemical ultra-advanced treatment reactor 10 .

The influent distributor 50 located at the lower portion of the bioelectrochemical ultra-advanced treatment tank 10 has a porous structure and serves to uniformly supply wastewater from the bottom to the top to the front end surface of the reactor.

The insulating electrodes 21 and 22 of the present invention are manufactured by coating a dielectric material 24 on the surface of the base electrode 23 having high electrical conductivity. Preferably, the base electrode 23 may be a titanium foil resistant to corrosion, and the dielectric material 24 used for surface coating of the base electrode is made of polyester, polyvinyl chloride, polypropylene, polyvinylidene fluoride, etc. It may be a polymer material or a ceramic material. An electrode without a surface coating may be used in the bioelectrochemical ultra-high-level treatment tank, but if the voltage applied to the electrode to maintain the electric field is 1.5 V or higher, energy loss may occur due to the electrolysis reaction of water occurring on the electrode surface, The disadvantage is that the electrode is easily corroded.

The conductive medium 60 is positioned between the insulating electrodes 21 and 22 . The conductive medium 60 not only serves to promote interspecies electron transfer of the electroactive bacteria, but also serves as a support for the electroactive bacteria to attach and grow. The conductive medium 60 may be a conductive carbon-based material or magnetite, but is preferably a carbon-based material such as carbon black, activated carbon, carbon nanotubes, graphene or graphite in the form of particles (60) or plate (61). am. A more preferable form is particulate activated carbon having a diameter of 5 to 10 mm. The carbons have excellent biocompatibility as well as high conductivity, which is advantageous for the growth of electroactive bacteria. When the carbons are pre-treated to oxidize and remove contaminants present on the surface and improve porosity and conductivity, the biomass of the electroactive bacteria attached to and growing on the surface is increased, and there is an advantage of improving electron transfer between species. A preferred pretreatment method of the carbons is a Fenton oxidation method. When the Fenton oxidation method is used, all foreign substances such as organic substances present on the carbon surface are removed, and the voids, roughness, and electrical conductivity of the surface are increased, so that the attachment of electroactive bacteria is facilitated. The Fenton oxidation method may be performed by supporting carbons in a Fenton solution in which hydrogen peroxide and iron ions are mixed and stirring.

When the insulating electrodes 21 and 22 are polarized using an external voltage source 30, an electric field is formed between the insulating electrodes 21 and 22, and some microorganisms exposed to the electric field express electroactive genes and thus electroactive bacteria. will be changed to The electroactive bacteria exposed to the electric field rapidly and effectively metabolize the substrate by direct interspecies electron transfer by physical contact or mediated interspecies electron transfer mediated by abiotic redox substances. . The abiotic redox material may be a material such as flavin and quinone secreted by microorganisms in an endogenous state, or a humic material.

The electric field formed in the bioelectrochemical ultra-high-level processing reactor 10 by polarizing the insulating electrodes 21 and 22 to positive and negative poles is 0.2 V/cm to 3.3 V/cm, preferably 0.83 V/cm. If the electric field is less than 0.2 V/cm, the strength of the electric field is weak and the heterogeneous electron transfer phenomenon of the electroactive bacteria is not active, so that the wastewater treatment efficiency may be lowered. As the number of species decreases, the amount of electrons transferred between species decreases, and the coating layer on the surface of the insulating electrode easily weakens.

As the seeding sludge injected at the initial stage of operation of the bioelectrochemical ultra-advanced treatment tank, activated sludge of a bioreactor that can be collected from an existing wastewater treatment facility, anaerobic sludge living in an anaerobic digestion tank of sewage sludge, or a mixture thereof can be used. .

In the present invention, when the microorganisms contained in the inoculum are exposed to an electric field, some microorganisms express electroactive genes to change into electroactive bacteria, and when continuously exposed to an electric field in a bioelectrochemical ultra-high-level treatment tank, these microorganisms grow dominantly. The electroactive bacteria include exoelectrogens and electrotrophs. The in vitro electron-emitting bacteria are bacteria that transfer electrons to the outside of cells, and electrotrophs are bacteria that are activated by an electric field and use electrons transferred from the electron-emitting bacteria. The electron-trophic bacteria grow in a bulk solution exposed to an electric field, and are bacteria capable of taking electrons directly from the in vitro electron-emitting bacteria or taking electrons through the mediation of abiotic redox substances.

The sewage wastewater that can be treated at a very high level by the upflow bioelectrochemical device according to the present invention is diverse, such as domestic sewage, industrial wastewater, food wastewater, leachate, livestock and livestock wastewater, aquaculture wastewater, and the like. However, even in the case of low-concentration wastewater characterized in that the chemical oxygen demand (COD) is 40 mg/L or less and the total nitrogen (TN) concentration is 20 mg/L or less, it can be effectively treated with ultra-high-level treatment. In the biological treatment of wastewater, the concentration of contaminants as a substrate is an important factor determining treatment efficiency. Therefore, if the substrate affinity of microorganisms is low, it is impossible to effectively treat low concentrations of contaminants. Conventionally, there have been many cases in which wastewater is first treated by physicochemical methods such as sedimentation and then biologically secondarily treated and then discharged. However, in recent years, where environmental management of aquatic systems has become a major social issue, standards for effluent from wastewater treatment facilities are gradually being strengthened. Therefore, in order to satisfy the strengthened effluent standards, additional ultra-advanced treatment corresponding to the tertiary treatment of the effluent from the secondary treatment of the wastewater treatment plant is absolutely necessary. However, the biological ultra-advanced treatment of the secondary treatment effluent from the wastewater treatment plant had low treatment efficiency and economic feasibility due to thermodynamic limitations. In the present invention, as a method of improving the substrate affinity, a method of improving the metabolic process of microorganisms by improving the heterogeneous electron transfer between electroactive bacteria such as in vitro electron-emitting bacteria and electrontrophic bacteria is used.

The present invention provides a method for ultra-advanced treatment of wastewater using an upflow bioelectrochemical device comprising the following steps.

Step 1: supplying the seeding sludge containing the electroactive bacteria to the bioelectrochemical ultra-advanced treatment tank 10;

Second step: injecting wastewater in an up-flow manner into the bioelectrochemical ultra-advanced treatment tank 10 to which the seeding sludge is supplied;

Step 3: Inject a conductive medium 60 into the bioelectrochemical ultra-advanced treatment tank 10 supplied with the wastewater, and install dielectric materials-coated insulating electrodes 21 and 22 between the electrodes at 0.2 V Applying a voltage such that an electric field of /cm to 3.3 V/cm is formed.

In the bioelectrochemical ultra-advanced treatment tank 10, a porous influent water distributor 50 is installed at the bottom, and insulating electrodes 21 and 22 are installed in the effective part of the bio-electrochemical ultra-advanced treatment tank in which the wastewater treatment is in progress. A conductive medium 60 is filled between the insulating electrodes 21 and 22, and a passage through which the treated water flows out is located.

The volume of the seeding sludge initially injected for the operation of the bioelectrochemical ultra-advanced treatment reactor 10 is 40 to 60% of the effective volume of the reactor 10, preferably 50%. When the seeding sludge is supplied at less than 40%, it takes more time for the dominance of the electroactive bacteria, and thus the initial operation time may be lengthened, and even if the seeding sludge exceeds 60%, the dominance time of the electroactive bacteria is similar.

The wastewater is supplied in an upward flow through the influent distributor 50 of the bioelectrochemical ultra-advanced treatment tank 10 to which the seedling sludge is supplied, so that the seeding sludge and the wastewater come into contact, and the bioelectrochemical ultra-advanced treatment reactor by the supplied wastewater When the insulating electrodes 21 and 22 of (10) are submerged, a voltage is applied so that an electric field of 0.2 V/cm to 3.3 V/cm is formed between the insulating electrodes 21 and 22 to polarize the electrodes.

The conductive medium 60 filled between the insulating electrodes 21 and 22 is composed of carbons with excellent biocompatibility. It is porous and has improved surface roughness by pre-treatment using it. When the electroactive bacteria predominantly grow due to the electric field formed by the insulating electrode, effective treatment is possible not only in wastewater but also in wastewater with a low concentration of contaminants, such as secondary treated water from sewage treatment facilities.

The present invention will be described in detail through the following examples.

Example

<Upstream bioelectrochemical ultra-advanced processing device>

The upflow bioelectrochemical device of the present invention used in the embodiment is an inflow water distributor 50, a bioelectrochemical ultra-high-level processing reactor 10, insulating electrodes 21 and 22, a conductive medium 60, a DC power supply device 30 ), and a conducting wire (40).

The bioelectrochemical ultra-advanced treatment tank 10 is made of rectangular acrylic resin, and at the bottom of the bio-electrochemical ultra-advanced treatment tank 10, the inflow water is evenly supplied to the bioelectrochemical ultra-advanced treatment tank 10 in an upward flow manner. A porous influent distributor 50 made of a plate was installed. Insulated electrodes 21 and 22 were vertically installed at intervals of 3 cm inside the bioelectrochemical ultra-advanced treatment tank 10, and a conductive medium 60 was filled in the remaining internal space of the bioelectrochemical ultra-advanced treatment tank 10. An outlet for discharging purified treated water was installed at the upper portion of the bioelectrochemical ultra-high-level treatment reactor 10 .

A DC voltage source 30 is connected to the insulating electrodes 21 and 22 so that, when a voltage is applied, the insulating electrodes 21 and 22 are polarized to form an electric field (see FIG. 1 ). The insulating electrodes 21 and 22 were manufactured by coating the surface of a 0.3 mm thick titanium foil with polyester, which is a dielectric material.

Activated carbon 60 having excellent conductivity and biocompatibility was used as the conductive medium 60 (see FIG. 2 ). The conductive medium 60 used in the example was loaded in a Fenton solution in which 7.5 g/L of hydrogen peroxide and 1 g/L of iron ions were mixed, pretreated by stirring at 250 rpm for 1 hour, washed and dried. Activated carbon particles of 5 to 8 mm were used.

<Operation of upstream bioelectrochemical ultra-advanced processing equipment>

The upflow bioelectrochemical device for ultra-advanced treatment of wastewater of the present invention was operated in the following manner. First, a one-to-one mixture of the aerobic sludge collected from the bioreactor of the sewage treatment plant and the anaerobic sludge (seeding bacteria) collected from the anaerobic digester was inoculated into the bioelectrochemical ultra-advanced treatment tank 10 . The insulated electrodes 21 and 22 are polarized while continuously injecting wastewater in an upward flow through the inflow water distributor 50 installed at the bottom of the bioelectrochemical ultra-high-level treatment tank 10 to form an electric field between the electrodes of 0.83 V/cm. made it The seeding bacteria expressed electroactive genes by the electric field formed between the insulated electrodes 21 and 22 to transform into electroactive bacteria to grow dominantly, and to the secondary treatment water of sewage treatment facilities by transferring electrons between them. The low concentrations of organic matter and nitrogen contained were made to be highly processed. The treated water of the upflow bioelectrochemical device for the ultra-advanced treatment was discharged through the upper outlet.

1) Examples and Comparative Examples 1: Advanced purification of low-concentration secondary treatment wastewater

The model wastewater used in the tertiary treatment example of the secondary treatment water of the low concentration sewage treatment facility for Example (1) was synthesized based on the effluent standard of the wastewater treatment plant, and its characteristics are shown in <Table 1>. In Example 1, the model wastewater was supplied to the upflow bioelectrochemical device having the above structure so that the hydraulic residence time was 60 minutes, and an experiment was conducted in the above-described manner. In Comparative Example (1), an electric field was not formed in the ultra-high-level bioelectrochemical treatment tank, but the experimental apparatus and other methods were the same as in Example (1).

Composition (1ℓ) Analysis Kinds content Chemical Oxygen Demand (COD) Total Nitrogen (TN)
(Nitrogen content ratio, molar ratio) CH ₃ COONa 0.051g 40mg/L 20mg/L
(Ammonia nitrogen: nitrite nitrogen: nitrate nitrogen = 80: 2: 18) KCl 0.005g NH ₃ Cl 0.061g NaCO ₂ 0.002g KNO ₃ 0.023g

The chemical oxygen demand (COD) of treated water, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen were analyzed according to the standard method once every 2 days while operating the upflow bioelectrochemical device of the present invention for a total of 40 days. .

3 is a change with time of the chemical oxygen demand (COD) of Example 1 (BER) and Comparative Example 1 (Control).

According to the results of FIG. 3 , in both Example 1 and Comparative Example 1, the water quality of the effluent was stabilized after about 12 days. However, in the effluent, the chemical oxygen demand of Comparative Example 1 was as high as 16.2 mg/L, but the chemical oxygen demand of Example 1 was as low as 1.49 mg/L.

4 is a change with time of the total nitrogen (T-N) measured in Example 1 (BER) and Comparative Example 1 (Control).

According to the results of FIG. 4 , the total nitrogen concentration of the effluent in Comparative Example 1 was stabilized at 18.6 mg/L, while the total nitrogen concentration of the effluent in Example 1 was sharply decreased from about 4 days after the start of operation, and 3.48 mg/L A stable value was maintained at low concentrations of

According to the above results, the conventional biological reactor (Comparative Example 1) indicates that it is difficult to effectively treat secondary treated water having a low concentration of contaminants as a substrate. On the other hand, the upflow bioelectrochemical device (Example 1) of the present invention shows that ultra-high-level treatment of low-concentration contaminants is possible by heterogeneous electron transfer of electroactive bacteria.

2) Examples and Comparative Example 2: Ultra-advanced treatment of secondary treatment effluent from actual sewage treatment facilities

In Example 2) and Comparative Example 2), an upflow type bioelectrochemical device for ultra-advanced treatment of wastewater of the present invention, which is the same as that used in Example 1) and Comparative Example 1), respectively, using secondary treatment effluent from an actual sewage treatment facility and method were used to verify processing performance. The characteristics of the secondary treated water of the actual sewage treatment facility are shown in Table 2 below.

Analysis Chemical Oxygen Demand (COD) Total nitrogen (TN)
(Nitrogen content ratio, molar ratio) 5.88 to 6.11 mg/L 4.74 to 6.03 mg/L
(Ammonia nitrogen: nitrite nitrogen: nitrate nitrogen = 1: 0: 2.14) ammonia nitrogen 1.5 to 1.95 mg/L Nitrous Nitrogen 0mg/L nitrate nitrogen 3.22 to 4.25 mg/L

5 is a chemical oxygen demand (COD) result measured in Example 2 (BER) and Comparative Example 2 (Control).

According to the results of Figure 5, in both Example 2 and Comparative Example 2, the COD of the effluent was stabilized after about 12 days. The effluent COD of Example 2 was very low, about 1.5 mg/L. This shows that even though the COD value of the influent is very low as 5.88 to 6.11 mg/L by the present invention, it is possible to perform ultra-high-level treatment. This is the result of verifying that organic pollutants in low-concentration secondary treatment wastewater can be treated at a very high level using the upflow bioelectrochemical device of the present invention.

6 is a result of total nitrogen (T-N) concentration measured in Example 2 (BER) and Comparative Example 2 (Control).

As shown in FIG. 6 , in Comparative Example 2, the total nitrogen concentration in the influent was 4.74 to 6.03 mg/L, and the total nitrogen concentration in the effluent was about 5.8 mg/L, confirming that the total nitrogen was not additionally removed. However, the total nitrogen concentration of the effluent in Example 2 under the electric field formed by polarizing the insulating electrode was 2.62 mg/L, indicating that additional total nitrogen can be removed according to the present invention. This means that using the upflow bioelectrochemical device of the present invention, it is possible to ultra-highly treat low-concentration secondary treatment effluent from a sewage treatment facility.

3) Examples and Comparative Example 3: Ultra-advanced treatment of actual wastewater

In Example 3) and Comparative Example 3), the actual sewage treatment facility influent was injected into the upflow bioelectrochemical device for ultra-advanced treatment of wastewater of the present invention so that the hydraulic residence time was 1 hour, 3 hours, and 5 hours. ) and Example 2), respectively, and the processing performance was verified by the same method. In addition, the effect was verified by returning the runoff at a hydraulic residence time of 5 hours. The characteristics of the inflow wastewater of the actual sewage treatment facility are shown in Table 3 below.

Analysis Chemical Oxygen Demand (COD) Total nitrogen (TN)
(Nitrogen content ratio, molar ratio) 62.51 to 68.21 mg/L 26.88 to 30.15 mg/L
(Ammonia nitrogen: nitrite nitrogen: nitrate nitrogen = 1: 0: 0.08) ammonia nitrogen 13.12 to 15.44 mg/L Nitrous Nitrogen 0mg/L nitrate nitrogen 1.05 to 1.35 mg/L organic nitrogen 10.89 to 14.65 mg/L

7 shows the chemical oxygen demand (COD) processing performance according to the hydraulic residence time and conveyance of Example 3 (BER) and Comparative Example 3 (Control).

According to the results of FIG. 7 , when the hydraulic residence time was 1 hour, it was confirmed that in both Example 3 and Comparative Example 3, they were stabilized after about 12 days, and the chemical oxygen demand (COD) of the effluent of Example 3 was about 6.00. mg/L. Considering that the chemical oxygen demand of the incoming real wastewater is 62.51 to 68.21 mg/L, it was found that the real wastewater can be sufficiently treated. In addition, when the hydraulic residence time was adjusted to 3 hours or more, the chemical oxygen demand (COD) concentration of the effluent was reduced to 1.84 to 2.90 mg/L. However, the chemical oxygen demand (COD) concentration of the effluent of Comparative Example 3 was maintained at 11.91 to 12.40 mg/L even though the hydraulic residence time was adjusted to 3 hours or more, so that the real sewage could no longer be treated at a low concentration.

8 shows the total nitrogen (T-N) treatment performance of Example 3 (BER) and Comparative Example 3 (Control).

As shown in FIG. 8, the total nitrogen concentration of the effluent of Comparative Example 3 was maintained at about 21.05 mg/L even when the hydraulic residence time was increased to 5 hours per hour and internally returned to 0.5Q, and the inflow total nitrogen concentration was 26.88 to The total nitrogen in the sewage of 30.15 mg/l was hardly treated. However, the total nitrogen concentration of the effluent in Example 3 in which a voltage was applied to the insulated electrode was about 11.28 mg/L when the hydraulic residence time was adjusted to 1 hour, 5.17 mg/L for 3 hours, and 4.15 for 5 hours. The removal efficiency was greatly improved with mg/L. In addition, when the hydraulic residence time was 5 hours and the internal return was 0.5Q, the total nitrogen concentration in the effluent was reduced to 2.98 mg/L. This means that it is possible to effectively treat sewage using an upflow bioelectrochemical ultra-high-level treatment tank in which voltage is applied to the insulated electrode.

Although the present invention has been described above using several preferred embodiments, these examples are illustrative and not restrictive. Those of ordinary skill in the art to which the present invention pertains will understand that various changes and modifications can be made without departing from the spirit of the present invention and the scope of the appended claims.

10: bioelectrochemical ultra-high-level processing reactor 21, 22: insulated electrode
23: base electrode 24: dielectric material
30: DC power supply device 40: lead wire
50: porous influent distributor 60: particulate conductive medium
61: plate-shaped conductive medium

Claims (8)

In the upflow bioelectrochemical device for ultra-advanced treatment of wastewater,
a bioelectrochemical ultra-advanced treatment tank in which wastewater is supplied in an upward flow by a porous influent distributor;
two or more insulating electrodes located inside the bioelectrochemical ultra-high-level processing reactor and coated with a dielectric material; and
a conductive medium disposed between the two or more insulating electrodes;
includes,
The wastewater is low-concentration wastewater or sewage treatment plant inflow water having a chemical oxygen demand (COD) of 40 mg/L or less or a total nitrogen (TN) concentration of 20 mg/L or less,
The conductive medium is a carbon-based particulate material with high biocompatibility, and is an up-flow bioelectrochemical device for ultra-advanced treatment of wastewater, characterized in that it is activated carbon particles pretreated with a Fenton solution mixed with hydrogen peroxide and iron ions.
delete delete The upflow bioelectrochemical device for ultra-advanced treatment of wastewater according to claim 1, wherein the polarization is applied by applying a voltage so that an electric field of 0.2 to 3.3 V/cm is formed between the two or more insulating electrodes.
[Claim 2] The upflow bioelectrochemical device for ultra-advanced treatment of wastewater according to claim 1, wherein the conductive medium is filled between the insulating electrodes in order to alleviate the attenuation of the electric field strength and promote the adhesion growth of electroactive bacteria. .
delete A first step of injecting seedling sludge into a bioelectrochemical ultra-high-level treatment tank;
a second step of supplying wastewater in an upflow manner to the bioelectrochemical ultra-advanced treatment tank to which the seedling sludge is supplied; and
An electric field of 0.2 to 3.3 V/cm between the electrodes is applied by injecting a conductive medium into the high-level bioelectrochemical treatment tank supplied with the wastewater, installing two or more insulating electrodes coated with dielectric materials, and then applying a voltage to the insulating electrodes. A third step of polarizing to form
The wastewater is low-concentration wastewater or sewage treatment plant inflow water having a chemical oxygen demand (COD) of 40 mg/L or less or a total nitrogen (TN) concentration of 20 mg/L or less,
The conductive medium is a carbon-based particulate material with high biocompatibility, and is an ultra-advanced treatment method of wastewater using an upflow bioelectrochemical device, characterized in that it is activated carbon particles pretreated with a Fenton solution mixed with hydrogen peroxide and iron ions.
[8] The method according to claim 7, wherein the hydraulic residence time for the ultra-advanced treatment of the wastewater is 60 to 480 minutes.

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