KR20110135042A - Pretreatment method of high concentrated ogranic sludges to applying for uasb - Google Patents

Abstract

PURPOSE: A pre-treating method for the upflow anaerobic sludge blanket(USAB) technique of high concentration organic wastes is provided to reduce the amount of water for reducing the concentration of solid materials and to implement the technique without a fine solid-liquid separator. CONSTITUTION: A pre-treating method pre-treats organic wastes before the organic wastes are introduced into a methane reactor(40) for an USAB technique. The pre-treating method includes the following: Digested liquid generated from a anaerobic digestion reaction is treated. The decomposition of organic wastes and the load of the organic wastes are reduced. SS and oil are reduced. Treated water is introduced into the methane reactor through an acid reactor(30).

Description

Pretreatment method for the application of BAS method of high concentration organic waste {PRETREATMENT METHOD OF HIGH CONCENTRATED OGRANIC SLUDGES TO APPLYING FOR UASB}

The present invention solves the problem of solid waste separation and removal of organic waste, which is a problem of the UASB (Upflow Anaerobic Sludge Blanket) process for producing biogas from organic waste, and thus enables low investment cost and small plant area in small and medium-sized plants. The present invention relates to a pretreatment method for the application of the UASB method of high concentration organic waste to enable the UASB method.

Food wastes and food processing by-products among organic waste resources are relatively small when considering the total amount of organic waste resources generated.

However, in Korea, due to the lack of technology for anaerobic digestion, the treatment of food waste and food processing by-products has mostly been reliant on composting and feed.In addition, even with such treatment methods, many organic waste resources are processed by marine discharge due to sluggish technology development and investment. It's happening.

Various researches are being conducted on the classification of organic matter for biological removal of nutrients contained in food waste and food processing by-products, nitrogen behavior, nitrification and denitrification characteristics, and phosphorus behavior, and denitrification for biological nitrogen removal. In the reaction, it is a situation to study the denitrification rate according to the internal and external carbon source.

In addition, in order to improve the convenience of the operation, researches to derive the optimum conditions for each step using the SBR (Sequencing Batch Reactor) process and treatment methods using the various floating and adhesion growth methods in connection with anaerobic and anoxic oxic processes are being studied. Anaerobic digestion, which has the advantage of recovering CH4, is most commonly used to remove high concentrations of organics, but has a disadvantage in that the initial reaction takes a long time. Recently, high rate anaerobic processes such as Upflow Anaerobic Filter (UAF), Anaerobic Attached Film Expanded Bed (AAFEB), and Upflow Anaerobic Sludge Blanket (UASB) have been developed and applied to many facilities. In particular, the UASB process is being applied in various industrial wastewater and municipal sewage treatment fields due to the advantages of securing a large amount of microorganisms in the reaction zone and the superior treatment efficiency.

However, the prior art to which the UASB method, which is one of the anaerobic digestion processes, is applied (Korea Patent No. 10-0750502 (Registration date August 11, 2007) 'The processing apparatus and the treatment apparatus of high concentration organic livestock manure through anaerobic digestion Treatment method of high concentration organic livestock manure through ', Republic of Korea Patent Registration 10-0569704 (Registration date 04.04.2006)' External circulation type anaerobic digestion apparatus using biogas lifting ', Korea Patent Registration 10-0853287 (Registration date 2008 Aug. 13, 'Livestock Wastewater Treatment Digestion System and Treatment Extinguishing Method Using the Same', Korean Patent Publication No. 10-2010-0028413 (published March 12, 2010) 'Method for treating high concentration organic wastewater' There is a problem of lowering the concentration of solids, and as a pretreatment technology, after desorption of food waste through the conventional solid-liquid separator, the SS is lowered through the process of microsolid-liquid separator and filtration. However, in the case of such a method, clogging, replacement, and cleaning processes are cumbersome, and there is a limit to low concentration of solids. Also, the use of a pretreatment device consumes a lot of power in operating as well as installing equipment. In economic terms, this can be a problem for practical plant applications.

Republic of Korea Patent Registration 10-0750502 (Registration Date August 11, 2007) Republic of Korea Patent Registration 10-0569704 (Registration date 04 Apr 2006) Korean Patent Registration No. 10-0853287 (Registration date August 13, 2008) Republic of Korea Patent Publication No. 10-2010-0028413 (published March 12, 2010)

In order to solve the above problems, the present invention is to apply the UASB process of high concentration organic waste, pretreatment of organic waste by precipitation before applying the UASB process, does not require expensive equipment or operation, low investment cost and small plant It is an object of the present invention to provide a pretreatment method for applying the UASB process of high concentration organic waste, which makes the UASB process applicable.

In order to achieve the above object,

In order to apply the UASB method, the present invention is a pretreatment method before introducing the organic waste into the methane reactor for biogasification,

Sewage treatment of digestive fluid generated during the anaerobic digestion reaction,

Organic matter decomposition and organic load reduction step of hydrolyzing digested liquor treated water that has undergone the sewage treatment at a ratio of 10 to 20 times weight to organic waste after introducing organic waste into a sump;

After introducing the organic waste that passed the organic decomposition and organic load reduction step into the sedimentation tank, the turbulence in the sedimentation tank by the membrane installed in the sedimentation tank is suppressed, and the sedimentation process is allowed to stand for 3 to 5 hours in a state of increasing sedimentation efficiency. SS reduction, oil removal step,

The main technical configuration of the pretreatment method for applying the UASB method of the high concentration organic waste, which is through the step of removing the upper and lower portions of the settling tank and the remaining treated water after passing through the acid reaction tank to the methane reactor.

And, the precipitation process in the settling tank is to be made by the addition of a flocculant to enhance the effect of separating and removing solids from organic waste,

The flocculant was added to a 30-fold weight of 0.1 N NH ₄ Cl solution, stirred at 150 to 300 rpm at room temperature, subjected to ammonium adsorption, and then subjected to adsorption of slurry clay at 100 to 110 ° C. After drying for 24 hours, the mixture was allowed to cool and injected through a sieve separation process of 200mesh in an amount of 5 to 15 mg based on the amount of organic waste (L).

As described above, the pretreatment method for applying the UASB method of the high concentration organic waste of the present invention does not need to use a fine solid-liquid separator to apply the UASB method by pre-treatment of the high concentration organic waste, and also to use the digested liquid treated water that is dumped at sea By utilizing it for water, it is possible to considerably lower the concentration of solids in organic waste, and to reduce the amount of water for lowering the concentration of solids, and to reduce the volume of the plant accordingly. For plants, this has the advantage of significantly reducing the investment costs.

1 is a front view showing the device configuration of the UASB method to which the present invention is applied.

Hereinafter, a detailed description of the technical configuration will be described with reference to the accompanying drawings.

1 is a front view showing the device configuration of the UASB method to which the present invention is applied,

Apparatus for the application of the UASB method consists of a collecting tank (10), sedimentation tank (20), acid reaction tank (30), methane reaction tank (40), effluent storage tank (50), gas storage tank (60) In addition, the present invention relates to a pretreatment method for applying the UASB method of the high concentration organic waste made through the collection tank (10) and the settling tank (20) configured in front of the acid reaction tank (30).

Looking briefly for the remaining reaction tank except for the collection tank (10) and the settling tank (20), the acid reaction tank 30 is installed in the front of the methane reaction tank 40, the volatile organic acid used as a substrate (feeding) of methane producing bacteria ( VFA), the pH through NaOH is maintained at 6.5 or more in order to control the pH optimum environment and load of methane producing bacteria.

The optimal environmental conditions of the methane producing bacteria is by was has the optimum conditions in the neutral, so pH 6.8 ~ 7.2, to methane of methanogens like transition small Acetic Acid, Propionic Acid, Lactic Acid , Butyric Acid, H 2, CO 2 CH 4 and Is converted to CO ₂ and organics are removed.

The methane reactor 40 is a xiangry type anaerobic sludge blanked reactor, flows from the bottom up, and is filled with a high concentration of anaerobic sludge (Granular Sludge), the filling amount is about 30% of the total methane reactor volume. The inflow water passes through the high concentration anaerobic sludge layer, where organic matter and organic acids are converted to methane, and the generated gas is collected and stored in the gas storage tank 60.

In addition, the effluent storage tank 50 installed at the rear end of the methane reaction tank 40 has a function of storing the effluent water of the organic waste passed through the methane reaction tank 40.

Hereinafter, looking at the pretreatment method which is the main technical configuration of the present invention,

In order to apply the UASB method, before the organic waste is introduced into the methane reaction tank 40 for biogasification,

Sewage treatment of digestive fluid generated during the anaerobic digestion reaction,

After the organic waste is introduced into the sump (10), the organic material decomposition, organic load reduction step of hydrolyzing the digestive fluid treated water after the sewage treatment at a ratio of 10 to 20 times the weight of the organic waste,

After introducing the organic waste that passed the organic decomposition and organic load reduction step into the settling tank 20, after removing the contaminants through the separation membrane 201 installed in the settling tank 20, SS reduction, oil remaining for 3 to 5 hours Removal step,

After removing the upper and lower portions of the settling tank 20 is passed through the acid reaction tank 30 is made through the step of introducing into the methane reaction tank (40).

The digestive fluid sewage treatment step is a process in which the digestive fluid generated in the anaerobic digestion reaction is used for sewage treatment of organic waste, and the digestive fluid generated in the anaerobic digestion reaction is subjected to primary denitrification, primary nitrification, and second treatment. It is used for denitrification, second nitrification, post-denitrification and reaeration, and is generally used for pretreatment of high concentration organic waste by going through the treatment performed in sewage treatment.

In this way, the digestive liquid, that is, the digestive liquid treated water, which has undergone the sewage treatment process is introduced into the sump tank 10, where the amount of the organic wastes filled in the sump tank 10 is 10 to 20 times by weight ratio.

If the amount of the water is more than 20 times, the size of each tank of the plant should be increased, the economical efficiency due to the manufacturing and construction costs disappear, and if the water is less than 10 times, the amount of influent flowing into the methane reactor 40 Since it is difficult to match the properties and the solids concentration, it is preferable that the amount of the hydrolyzate of the digested liquid treated water is 10 to 20 times by weight to the amount of organic waste.

That is, when the amount of water is low, it is difficult to meet the operating conditions according to the concentration of solids, and when the amount of water is too high, the size of the plant must be large, so that the amount of water is kept in the above range.

The organic wastes are specifically food wastes or food processing by-products, and the organic wastes are hydrolyzed in the collection tank 10 to decompose organic matters and reduce organic loads.

The organic waste that passed through the sump (10) is introduced into the settling tank 20, after removing the contaminants through the separation membrane 201 installed in the settling tank 20, left for 3 to 5 hours to reduce the SS and The oil is removed.

If the settling time in the sedimentation tank is less than 3 hours, the sedimentation efficiency of the solids may be higher than the concentration of the introduced solids. If the sedimentation time exceeds 5 hours, there is no significant effect on sedimentation. It affects the size and HRT (hydraulic residence time), the leaving time in the settling tank is preferably maintained within the range of 3 to 5 hours.

The precipitated solids generated in the settling tank are discharged to the outside by a pump connected to the lower part of the settling tank.

Precipitation in the settling tank 20 is made by a flocculant and a separation membrane, the flocculant is put into a 30 times weight of 0.1 N NH ₄ Cl solution and stirred at 150 ~ 300rpm at room temperature and then subjected to ammonium adsorption , After drying slurry for 24 hours at 100 ~ 110 ℃ after the adsorption process, allowed to cool and injected through a sieve separation of 200 mesh in 5 ~ 15mg of the amount of organic waste (L) It is.

The membrane separation treatment effect in parallel with the flocculant has the most stable permeation recovery rate and removal efficiency of SS, turbidity, humic acid and DOC, which are the most stable permeation recovery rate and fouling inducing agent.

The membrane for membrane separation may include a microfiltration (MF) membrane having a membrane pore size of 0.02 to 10 μm, an ultrafiltration (UF) membrane of 0.001 to 0.02 μm, and a reverse osmosis of 0.0001 to 0.001 μm. osmosis, RO) film is selected from any one selected.

The smaller the particle diameter, the lower the water permeation performance under the same pressure, and it is necessary to increase the pressure in order to maintain the water permeation performance. Therefore, the operation pressure increases in the order of microfiltration and ultrafiltration reverse osmosis.

As such, organic waste having undergone SS reduction and oil removal in the precipitation tank 20 is subjected to SS 500ppm and COD 5,000ppm treated water introduced into the methane reaction tank 40 through the acid reaction tank 30 installed at the rear of the precipitation tank. You will go through the process.

As described above, when the organic waste pretreatment method according to the present invention is applied, the organic load is converted to 2-8 kg COD / ㎥ × d (COD: 3000-9000 ppm) to convert the concentration of the influent, not the HRT change. As a result of operation, the gas generation amount was increased up to 8 kg COD / ㎥ × d without significant load, and the efficiency of removal was more than 90% even when the organic matter was removed.

SS of negative wastewater was introduced below 500 ppm during operation, but SS flowed out with increasing organic load, and pH appeared to be stable for each reactor.In the early stage, 1N-NaOH was consumed a lot, but after stabilization There was little consumption of NaOH due to the effluent return.

Organics removal was maintained at 95% or more during the run, and 90% efficiency was achieved when organic loads were raised to 8 kg COD / m 3 × d. In each tank, the removal rate of acid production tank was about 60%, and the methane production tank showed removal rate of 80%, which showed higher removal by Granular Sludge and easier removal of SCOD than TCOD.

In the case of VFA (Volatile Fatty Acid), Acetic Acid 50%, Propionic Acid 35%, Lactic Acid 25% and Butyric Acid were below 1%.

The pretreatment method for applying the UASB method of high concentration organic waste according to the present invention has an effect of reducing the operating cost and reducing the plant area when applied to medium and small scales, and thus has high economic feasibility.

10: sump tank
20: sedimentation tank
30: acid reactor
40: methane reactor
50: effluent storage tank
60: gas reservoir

Claims (4)

In order to apply the UASB method, as a pretreatment method before introducing the organic waste into the methane reactor for biogasification,
Sewage treatment of digestive fluid generated during the anaerobic digestion reaction,
After the organic waste is introduced into the sump (10), the organic material decomposition, organic load reduction step of hydrolyzing the digestive fluid treated water after the sewage treatment at a ratio of 10 to 20 times the weight of the organic waste,
After introducing the organic waste, which has undergone the organic decomposition and organic load reduction step, into the settling tank 20, the turbidity in the settling tank 20 is suppressed by the separation membrane 201 installed in the settling tank 20 to increase the settling efficiency. SS is left for 3 to 5 hours in the sedimentation process to reduce the SS, oil removal step,
The pretreatment method for applying the UASB method of the high concentration organic waste, characterized in that the step of removing the upper and lower portions of the settling tank 20 is passed through the acid reaction tank 30 and then introduced into the methane reactor (40). .
The method according to claim 1,
The precipitation process in the precipitation tank 20 is made by the addition of a flocculant,
The flocculant was added to a 30-fold weight of 0.1 N NH ₄ Cl solution, stirred at 150 to 300 rpm at room temperature, subjected to ammonium adsorption, and then subjected to adsorption of slurry clay at 100 to 110 ° C. Pre-treatment method for applying the UASB method of high-concentration organic waste to dry it for 24 hours to cool and to inject 5 ~ 15mg based on the amount (L) of organic waste by cooling through 200mesh sieve separation process.
The method according to claim 1,
The separation membrane 201 is a microfiltration (MF) membrane having a membrane pore size of 0.02 to 10 μm, an ultrafiltration (UF) membrane of 0.001 to 0.02 μm, and a reverse osmosis (RO) of 0.0001 to 0.001 μm. Pretreatment method for applying the UASB method of high concentration organic waste, characterized in that one of the selected one of the membrane.
The method according to claim 1,
Treated water introduced into the methane reactor (40) is SS 500ppm, COD 5,000ppm pretreatment method for applying the UASB method of high concentration organic waste, characterized in that.

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