KR100592332B1 - Advanced high rate anaerobic digester apparatus - Google Patents

Abstract

The present invention relates to a sewage sludge treatment apparatus, and more particularly, is introduced to concentrate the primary sludge through the first concentration tank, and is introduced to concentrate the secondary sludge through the second concentration tank or the thickener, After the primary sludge is mixed with the sludge discharged from the primary thickener and the secondary thickener or the thickener, respectively, and the primary heat is obtained from the mixed sludge while passing the mixed sludge, which is mixed with each other, through a primary heat exchanger. After passing heat through the second heat exchanger so that the sludge temperature is about 50 ° C., the sludge passes through the self-heating high temperature aerobic digester together with the air, and passes through the self-heating high temperature breathing digester. The temperature is about 50-60 ° C. due to the exothermic action of the high temperature microorganisms, which is passed through the first heat exchanger while the first concentration tank and the second The sludge flowing out from the thickener or the concentrator is mutually heat exchanged with the mixed sludge mixed with each other, cooled to about 40 ° C., and passed through a medium temperature anaerobic digester, and the solids of the passed sludge are transferred to a dehydrator and dehydrated.

In this heat exchange system, when the temperature of inflow sludge drops to about 10 ℃ in the cold season of winter season and the amount of biogas is not enough, the third heat exchanger is operated to inject sludge temperature 30-35 ℃ out of the digester. It was used for warming. Biogas generated in the middle temperature anaerobic digester is transferred to a generator (gas engine generator, gas turbine generator, fuel cell generator) to produce electricity, and the waste heat generated from the generator is sent to the second heat exchanger. It relates to a high efficiency anaerobic digester device configured to supply secondary heat to the sludge.

 This allows the high temperature microorganisms contained in the inlet sludge to be actively reacted by using a self-heating exhalation digester in front of the existing medium temperature anaerobic digester, and using the high-temperature sludge heat passing through the self-heating exhalation digester. It supplies heat to the sludge firstly by supplying heat, generates electricity by using the gas generated from the middle temperature anaerobic digester as an energy source for the operation of the generator, and uses the waste heat of the generator to generate the second temperature. By supplying heat to the heat exchanger, to provide a high-efficiency anaerobic digester device for providing the sludge to the secondary sludge temperature required by the self-heating hot digester.

Sewage, sludge, sewage sludge, middle temperature anaerobic digestion, anaerobic digester, self-heating high temperature aerobic digestion

Description

High efficiency Anaerobic Digester Apparatus {Advanced high rate Anaerobic Digester Apparatus}

1 and 2 is a schematic view showing a sewage treatment apparatus according to the prior art.

Figure 3 is a schematic diagram showing a high efficiency anaerobic digester according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: 1st concentration tank 2: 2nd concentration tank or thickener

3: first heat exchanger 4: second heat exchanger

5: self-heating high temperature aerobic digester 6: medium temperature anaerobic digester

7: dehydrator 8: generator

9: 3rd heat exchanger

The present invention relates to a sewage sludge treatment apparatus, and more specifically, to a high-temperature microorganism contained in sludge using a self-heating exhalation digester as a pretreatment to an existing anaerobic digester for treating primary and secondary sludge generated through a concentration tank. Active heat is generated to generate bio-heat, and by using the heat of the hot sludge which passed through the self-heating high-temperature exhalation digester, the heat is supplied to the first heat exchanger to provide the temperature required for the sludge as a primary. By using biogas generated from the digester, it is used as an energy source for the operation of a generator (gas engine, gas turbine, fuel cell) to produce electricity, and the heat is supplied to the second heat exchanger using the waste heat of the generator. , To provide a high efficiency anaerobic digester device that provides the temperature required for self-heating high temperature aerobic digester to secondary sludge A.

In this heat exchange system, when the temperature of inflow sludge drops to about 10 ℃ in the cold season of winter season and the amount of biogas is not enough, the third heat exchanger is operated to inject heat of sludge temperature 30-35 ℃ out of the digester. It was used for sludge warming. In general, sewage containing organic pollutants, nitrogen, and phosphorus depletes dissolved oxygen in water, destroying aquatic ecosystems, and eutrophicating water in lakes and reservoirs.

Thus, to prevent water pollution of rivers. Pollutants and nutrients contained in the wastewater should be removed before they enter the body of water, such as rivers.

To remove it. As a treatment method of wastewater treatment facilities, many biological treatment methods that are excellent in economics are applied. Among the biological treatment methods, organic matters using microorganisms such as activated sludge method and advanced treatment are removed, but microorganisms grown during organic matter removal process It is generated as sludge.

The treatment and disposal of sludge generated from organic matter removal process collects sludge and manure, livestock, and food waste from the primary and secondary sedimentation basins, and the concentrated sludge is transferred to the middle temperature anaerobic digester.

The digester supernatant after digestion to about 35 ° C. in the anaerobic digester is re-transmitted to the aeration tank of the activated sludge process, and the remaining solid sludge is infused with chemicals to increase the dehydration efficiency and dehydrated below the appropriate moisture. Is disposed of by external transport, incineration, or dumping at sea by transport vehicles for final disposal.

Recently, due to the ban on landfilling of sludge in landfill facilities, it is being temporarily disposed of by mixing with other waste such as construction waste and using it as landfill agent. In this case, landfill shortages are accelerating, and additionally, complex water treatment processes are required to treat leachate discharged from landfills.

In order to incinerate the sludge, the water content of the dehydrated sludge should be lowered to about 20 to 30%, and additional auxiliary fuel is required as the heat of the sludge is insufficient, and large dust collection facilities or odor removal are removed to remove the air pollution generated during incineration. There are many problems such as the need for facilities.

In addition, research on the reduction of organic sludge that has been recycled to agricultural land by using it as a composting method is being conducted, but it is not composted whole due to lack of carbon source and calorie of sludge, or other materials such as sawdust, manure or food waste. After mixing with the situation is composting. Especially in the case of sludge from sewage treatment facilities in industrial complexes, the effects of toxic substances such as heavy metals contained in the sludge should be identified.

In addition, the solidification method of mixing the solidifying agent in the sludge to minimize the elution of harmful substances such as heavy metals to reuse the solidified material. In the case of dumping at sea, the dumping method is the cheapest method at present, but the Ministry of Agriculture and Fisheries in Korea will prohibit dumping at sea in accordance with the pollution near the sea and the London Convention. Therefore, ultimate sludge reduction measures should be established, and continuous treatment and disposal measures should be devised in the absence of effective reuse plans.

1 and 2 is a schematic view showing a sewage sludge treatment apparatus according to the prior art, the conventional method for treating sewage sludge generally generated in the sewage treatment plant, the sewage sludge is concentrated in a concentration tank, the concentrated sludge is medium temperature anaerobic Processed in the digester to generate methane and carbon dioxide, and to dehydrate the solid to make a cake.

In the conventional method of FIG. 1, since the heating method of the anaerobic digester is a method of heating using steam or hot water using a boiler, most of the generated gas is burned in a boiler to produce steam or hot water. And most of the steam or hot water is used for heating the anaerobic digester, so it is difficult to recover the electric energy by power generation and the processing efficiency is low _. Most of the gas production is 0.4m ³ / kgVS _removed. As it is relatively small, cold weather requires additional heat from the external combustion energy (fuel, natural gas).

The method of FIG. 2 is a method recently attempted to introduce electricity into a generator instead of the boiler of FIG. 1 to generate electricity and to use waste heat for power generation for heating a digester. However, heat generated by waste heat alone is insufficient and requires external heating.

In order to solve the above problems, the present invention is to mix the secondary sludge made of surplus activated sludge with the first sludge made of particulate contaminants mixed in the conventional sewage, and the constituents, manure, food waste liquid, and the existing medium temperature By using a self-heating high temperature digestion tank as a pretreatment in the anaerobic digester, the high temperature microorganisms contained in the sludge are activated to react with the heat generated by the high temperature microorganisms to generate hydrolysis and organic acid. Sludge heat is used to supply heat to the first heat exchanger to provide the temperature required for the sludge firstly, and generators (gas engines, gas turbines, fuel cells) using biogas generated from the medium temperature anaerobic digester To generate electricity by using it as the energy source of operation, and to heat the secondary heat exchanger using the waste heat of the generator. Supplied, to self to provide a self-temperature sludge in a high temperature heat required by the aerobic digestion anaerobic digestion to provide a high-efficiency apparatus using a high temperature heat generating aerobic pretreatment. Secondly, if the sludge temperature of the sludge drops to about 10 ℃ in the cold weather of the winter season and the amount of biogas is not enough, the third heat exchanger is operated to heat up the sludge 30 ~ 35 ℃ out of the digester. Was used to inlet sludge warming.

      In addition, by introducing a self-heating high temperature aerobic digester into the existing medium temperature anaerobic digester as a pretreatment, pollutants (polymers, polysaccharides, surfactants, etc.) that are difficult to decompose under medium temperature anaerobic conditions are easily hydrolyzed and organic acid fermentation occurs under high temperature aerobic conditions. This allows for rapid methanation of organics in the subsequent anaerobic digester and increased gas production. This result can reduce the residence time of anaerobic digester by 50%. At this time, if the middle temperature anaerobic digester is installed in multiple stages, a part of the anaerobic digester can be converted into a self-heating high temperature aerobic digester, and is installed in the existing anaerobic digester to supply oxygen required for the high temperature aerobic microbial metabolism and to agitate the reactor. By supplying compressed air instead of biogas or using an ejector using a pump in a gas agitation facility, an oxygen supply and agitation can be simultaneously performed.

Hereinafter, embodiments of the present invention to which the above features are applied will be described in detail with reference to the accompanying drawings.

3 is a schematic view showing a high-efficiency anaerobic digester according to the present invention, which will be described in detail.

In sewage sludge treatment apparatus,

It is introduced to concentrate the primary sludge through the first concentration tank (1), it is introduced to concentrate the secondary sludge through the second concentration tank or the concentrator (2), the primary concentration tank (1) and the second After the primary sludge is obtained by mixing the sludge flowing out from the primary concentrator or the concentrator 2 with the mixed sludge mixed with each other, the manure, condensate, and food waste liquid are passed through the primary heat exchanger 3. While passing through the heat exchanger (4), the second sludge obtains heat at a temperature range of about 50 ° C., and then passes the self-heating hot aerobic digester (5) together with the air to activate the high temperature microorganisms contained in the sludge. . At this time, the temperature of the sludge spontaneously rises to about 60 ° C due to the metabolic activity of high temperature microorganisms. While passing the sludge passed through the self-heating high temperature digestion tank (5) to the first heat exchanger (3), the sludge discharged from the primary concentration tank (1) and the second concentration tank or the concentrator (2) are mixed with each other. Heat exchanged with the mixed sludge and cooled to about 40 ° C., passed through the medium temperature anaerobic digester (6), the sludge passed and deposited is transferred to the dehydrator (7), and the generated gas is transferred to the generator (8) to transfer electricity. To produce, the waste heat generated by the generator 8 is sent to the second heat exchanger (4) relates to a high-efficiency anaerobic digester device configured to supply secondary heat to the sludge.

In addition, when the temperature of the inlet sludge from the first and second concentration tanks 1 is lowered to about 10 ° C. during the cold winter season and the amount of biogas is not enough, the first concentration tank 1 is removed from the first concentration tank 1. A third secondary heat exchanger (9) is added to the pipe to which the primary heat exchanger (3) is connected, and the sludge flowing out of the middle temperature anaerobic digestion tank (6) is transferred to the third secondary heat exchanger (9). , The heat exchanger is heated to the first and second sludge flowing out from the secondary concentration tank (1,2) to be heated.

If the temperature of the sludge drops to about 10 ℃ in the cold weather of the winter season and the amount of biogas is not enough, the third heat exchanger is activated to heat the sludge 30 ~ 35 ℃ out of the medium temperature anaerobic digester. Was used to inlet sludge warming.

      In addition, when converting the existing medium temperature anaerobic digester of gas stirring type into self-heating high temperature aerobic digester, Root's blower, compressor, ejector, etc. In the exothermic high temperature aerobic digester (5), the supply and stirring of oxygen required by the high temperature aerobic microorganism is performed.

      Referring to the principle of operation of the embodiment according to the present invention in detail.

In general sewage, particulate contaminants are mixed, and excess 0.8% of TS (Total Soild) is passed through the primary concentration tank (1) to the primary concentration tank (2). Intermix with secondary sludge consisting of activated sludge. At this time, the concentration of TS in each sludge is concentrated to 2.0-5.0%. This mixed sludge can be mixed with manure, manure, and food waste as necessary. The winter temperature of this mixed sludge is approximately 10 ° C.-16 ° C. and in summer 20 ° C.-30 ° C.

The sludge is heated to approximately 35 ° C. by the 60 ° C. liquid sludge and the first heat exchanger 3 that have passed through the self-heating high-temperature exhalation digester 5, and exchanges waste heat of the generator 8 for the second heat exchange. The temperature of the sludge passed through the first heat exchanger 3 is increased from 35 ° C. to about 50 ° C. by transferring to the machine 4.

The sludge raised in the temperature range is transferred to the self heating pyrophoric digestion tank 5 together with the air, and the temperature is raised by the self heating pyrogen action of the high temperature microorganism in the self heating pyrophoric digestion tank 5, and the temperature is approximately 60 ° C. It is spilled in the liquid state.

The sludge in the liquid state at 60 ° C is fed to the first heat exchanger (3) and passes through the primary concentrate tank (1) and the secondary concentrate tank or concentrator (2), respectively. The sewage sludge temperature of TS is raised to approximately 35 ° C., and the sludge in the liquid state at 60 ° C. is cooled to about 40 ° C. and supplied into the mesophilic anaerobic digester 6. This allows the medium temperature anaerobic digester to maintain the temperature in the digester at 35 ° C. without additional external warming.

The sludge deposited inside the anaerobic digester in the middle temperature anaerobic digester (6) is drawn and supplied to the dehydrator (7), and the volume of the dehydrated sludge cake is about 10-30% smaller than the amount of cake generated in the conventional anaerobic digester. . Biogas generated by anaerobic decomposition of organic matter in the inflow sludge is introduced into the generator 8 to produce electricity.

Waste heat, which is discarded to the outside during electricity production of the generator 8, is transferred to the second heat exchanger 4, and the temperature of the sludge in which the temperature is raised in the primary heat exchanger 3 is raised to about 50 ° C in a second order. It is to let. This temperature range is to provide optimum temperature conditions for the metabolism and self-heating of the high temperature microorganisms in the self-heating high temperature aerobic digester (5).

As another embodiment of the present invention,

In the case where the middle temperature anaerobic digester has good treatment efficiency and the amount of gas is produced or the temperature is good even in winter,

The primary sludge 1 is introduced to concentrate the primary sludge formed of the particulate matter mixed in the normal sewage, and the secondary sludge composed of the surplus activated sludge through the secondary concentration tank or the concentrator 2. Mixed sludge mixed with sludge discharged from the first concentration tank 1 and the second concentration tank or the concentrator 2, respectively, which flows in to concentrate the manure, the animal waste, and the food waste liquid, and the first heat exchanger 3 After acquiring the primary heat to the sludge mixed while passing through), the first heat exchanger 3 passes through the first heat exchanger 3 while acquiring the heat to the second sludge while passing through the second heat exchanger (4). The sludge flowing out from the primary concentration tank (1) and the secondary concentration tank or the concentrator (2) is allowed to mutually heat exchange with the mixed sludge mixed with each other, and then cooled to pass through the medium temperature anaerobic digestion tank (6), and the passed sludge. Deposition The sludge in solid phase is transferred to the dehydrator 7, and the generated gas is transferred to the generator 8 to produce electricity. The waste heat generated by the generator 8 is transferred to the second heat exchanger 4. ) To supply secondary heat to the sludge.

As described above, the present invention efficiently utilizes the calorific value of the high temperature microorganisms generated in its own device and the generated waste heat of the generated gas, even without a separate energy source from the outside. There is no need for energy.

In addition, the heating method of the existing medium temperature anaerobic digester converts most of the generated gas (biogas) into steam or hot water and uses it to warm the digester, so there is almost no energy production that can be sent out of the system. Secondary heat of combustion is required.

However, the present invention can transfer the entire amount of biogas generated in the middle temperature anaerobic digester to the electric generator to be used for power generation, so that most of the generated electricity can be sent out of the system, and efficient heat exchanger use and bioreaction heat can be used in winter. This eliminates the need for external auxiliary combustion heat.

In addition, organic materials, which are difficult to decompose under the existing medium temperature conditions, can be easily hydrolyzed and acid fermented under high temperature aerobic conditions, thereby enabling rapid methane gasification in a medium temperature anaerobic digester. As a result, the decomposition time in the middle temperature anaerobic digester can be reduced by about 50%, and the sludge cake generation amount can be reduced by 10-30% compared to the existing one due to the increase in the removal efficiency of organic matter.

Claims (3)

In sewage sludge treatment apparatus, The primary sludge 1 is introduced to concentrate the primary sludge formed of the particulate matter mixed in the normal sewage, and the secondary sludge composed of the surplus activated sludge through the secondary concentration tank or the concentrator 2. Mixed sludge mixed with sludge discharged from the first concentration tank 1 and the second concentration tank or the concentrator 2, respectively, which flows in to concentrate the manure, the animal waste, and the food waste liquid, and the first heat exchanger 3 After acquiring the primary heat to the sludge mixed while passing through), and after passing the heat through the second secondary heat exchanger 4 to obtain the heat to the temperature range of 50 ℃ to the second sludge, the high temperature microorganisms contained in the sludge Passes the self-heating hot expiratory digester (5) together with air so as to activate the self, and passes the sludge passing through the self-heating exhaled digestive digester (5) to the first heat exchanger (3). 1) and 2nd The sludge flowing out from the thickener or the concentrator 2 is mutually heat exchanged with the mixed sludge mixed with each other, and then cooled and passed to the middle temperature anaerobic digestion tank 6, and the solid sludge deposited in the passed sludge is dehydrator ( 7), the generated gas (Biogas) is transferred to the generator (8) to produce electricity, the waste heat generated by the generator (8) is sent to the second heat exchanger (4) to the sludge 2 High efficiency anaerobic digester device, characterized in that configured to supply the heat shield. In sewage sludge treatment apparatus, In the case where the middle temperature anaerobic digester has good treatment efficiency and the amount of gas is produced or the temperature is good even in winter, The primary sludge 1 is introduced to concentrate the primary sludge formed of the particulate matter mixed in the normal sewage, and the secondary sludge composed of the surplus activated sludge through the secondary concentration tank or the concentrator 2. Mixed sludge mixed with sludge discharged from the first concentration tank 1 and the second concentration tank or the concentrator 2, respectively, which flows in to concentrate the manure, the animal waste, and the food waste liquid, and the first heat exchanger 3 After acquiring the primary heat to the sludge mixed while passing through), the first heat exchanger 3 passes through the first heat exchanger 3 while acquiring the heat to the second sludge while passing through the second heat exchanger (4). The sludge flowing out from the primary concentration tank (1) and the secondary concentration tank or the concentrator (2) is allowed to mutually heat exchange with the mixed sludge mixed with each other, and then cooled to pass through the medium temperature anaerobic digestion tank (6), and the passed sludge. Deposition The sludge in solid phase is transferred to the dehydrator 7, and the generated gas is transferred to the generator 8 to produce electricity. The waste heat generated by the generator 8 is transferred to the second heat exchanger 4. High efficiency anaerobic digester device, characterized in that made to send to the secondary heat to the sludge. The method according to claim 1 or 2, When the temperature of the inflow sludge from the primary concentration tank 1 drops to about 10 ° C. during the cold winter season and the amount of gas generated is not sufficient, the primary heat exchanger 1 is discharged from the primary concentration tank 1. 3) add a third heat exchanger (9) to the pipe connected to, and transfer the sludge flowing out of the medium temperature anaerobic digestion tank (6) to the third heat exchanger (9) to the first and second concentration tanks ( High efficiency anaerobic digester device, characterized in that the heat exchanged with the first and second sludge flowing out from 1,2) to be heated.

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