KR20150096105A - Method and apparatus for treating organic waste - Google Patents

Abstract

The present invention relates to a method for processing organic wastewater using an anaerobic digestion apparatus whereby limonen is added in a storage tank or a hydrolysis decomposition tank which stores organic wastewater before being transferred to the hydrolysis decomposition tank. The storage tank, the hydrolysis tank, an acid generation tank, or the anaerobic tank is not heated or is heated less by using an external energy source. Organic materials, which are easy to be coagulated at low temperatures, can be dispersed and emulsified to be fine. Processing efficiency of an anaerobic digestion process can be increased by maximizing activity of microorganisms participating in anaerobic digestion through bioaugmentation. Difference of seasonal processing efficiency can be reduced.

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for treating organic wastewater,

The present invention relates to a method for treating organic wastewater and an apparatus used therefor.

Due to the prohibition of marine dumping of organic wastewater, it is urgent to develop treatment technology for high concentration organic wastewater such as wastewater sludge, food wastewater, and livestock wastewater. Organic wastewater can be treated through an aerobic digestion process or an anaerobic digestion process.

The aerobic digestion process can be easily applied not only to sludge but also to high concentration wastewater and refractory wastewater because organic sludge decomposable in the presence of oxygen is carried out by a biological mechanism.

Although the anaerobic digestion process requires higher technology in maintenance than the aerobic digestion process, it is not affected by the overload of the high concentration wastewater. The sludge production is less than the aerobic digestion process and the final sludge can be reduced, It is possible to reduce organic matter at the concentration of solid matter, and it is widely used for the treatment of organic wastewater in that it can recover energy in the form of methane gas or the like.

Organic wastewater, for example, food wastewater, contains a large amount of oil as much as 8 to 18% on a dry weight basis, and the oil content of the organic wastewater is low due to low specific gravity, or by binding to fibers contained in vegetables or fruits, It is difficult to carry out the anaerobic digestion process because it is difficult to agitate and thus the microbial contact with the microbes is not performed well and the decomposition is not performed well, There is a problem in that the yield of methane production is remarkably lowered and overloading of the anaerobic digestion process occurs and if the organic acid production in the acidogenic tank is insignificant, organic acid is generated in the methane production tank to inhibit the activity of methanogenic bacteria .

Korean Patent No. 10-1157819 discloses an acid fermentation tank including a scum separator, a scum separated from an acid fermentation tank, a hydrolysis tank in which the precipitated sludge is hydrolyzed by a strong base, and an acid fermentation tank And an anaerobic digestion tank for treating the liquid component of the scum, wherein the hydrolysis tank and the strong bases are separately provided for acid hydrolysis of the scum containing the fat component, There has been a problem that a large amount of energy is consumed to heat the bath to 75 DEG C or higher.

It is an object of the present invention to provide an anaerobic digestion tank which is capable of heating a storage tank, hydrolysis tank, acid tank or anaerobic digestion tank at a low temperature The present invention provides an organic wastewater treatment method capable of maximizing the activity of microorganisms involved in anaerobic digestion by dispersing and emulsifying organic substances that are easy to solidify and making them microorganisms and bioaugmentation.

The present invention also provides an anaerobic digestion apparatus for use in the method for treating organic wastewater.

To achieve the above object, the present invention provides a hydrolysis tank for hydrolyzing carbohydrates, proteins and lipids of organic wastewater into monomers; An acidogenic group in which the monomer is converted to an organic acid; And a methane generation tank in which methane is generated from the organic acid, characterized in that limonene is added to organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank in an anaerobic digestion apparatus using an anaerobic digestion apparatus And a method for treating organic wastewater.

The present invention also relates to a hydrolysis tank for converting hydrocarbons, proteins and lipids of organic wastewater into monomers by hydrolysis; An acidogenic group in which the monomer is converted to an organic acid; And a methane generation tank in which methane is produced from the organic acid, characterized in that an input device for adding limonene to organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank is provided in the anaerobic digester, An anaerobic digester is provided.

The organic wastewater treatment method and the anaerobic digestion apparatus used in the method of the present invention can be applied to an organic wastewater treatment method and an anaerobic digestion apparatus which are capable of dispersing and emulsifying organic substances which are not heated using an external energy source, Thereby maximizing the activity of the microorganisms involved in anaerobic digestion through bioaugmentation, thereby increasing the treatment efficiency of the anaerobic digestion process and eliminating the variation in seasonal treatment efficiency.

1 to 3 are longitudinal cross-sectional views illustrating an operation process of a bubble generator added to a microorganism propagation tank according to an embodiment of the present invention.

The present invention relates to a hydrolysis tank which hydrolyzes carbohydrates, proteins and lipids of organic wastewater into monomers; An acidogenic group in which the monomer is converted to an organic acid; And a methane generation tank in which methane is generated from the organic acid, characterized in that limonene is added to organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank in an anaerobic digestion apparatus using an anaerobic digestion apparatus By weight based on the weight of the organic wastewater.

The organic wastewater according to the present invention is not particularly limited as long as the organic wastewater containing organic matter is not particularly limited. For example, the organic wastewater sludge, food wastewater, food wastes and animal wastewater have an organic matter content of 20000-170000 mg / The organic wastewater to which the method or apparatus of the present invention is preferably applied may have a lipid content of 1 to 20% by weight, more preferably 3 to 18% by weight, , Even more preferably 5 to 16 wt%.

The high concentration organic wastewater, particularly the wastewater having a high lipid content, is characterized in that the microorganisms acting on the anaerobic digestion take longer to extinguish the lipid than the carbohydrate source, and that anaerobic digestion including anaerobic digestion tanks, storage tanks, hydrolysis tanks, It is preferable that the method or apparatus of the present invention is applied in that the treatment efficiency drops sharply when the water temperature of the organic wastewater to be treated in the apparatus falls below 15 ° C, and the anaerobic digestion apparatus is liable to be overloaded.

The hydrolysis tank in which the carbohydrates, proteins and lipids are hydrolyzed into monomers and the acidogenic tank in which the monomers are converted into organic acids are not only provided with physically separated hydrolysis tanks and acid tanks, Includes a case where the functions of the hydrolysis tank and the acid production tank are integrally performed, and the hydrolysis and the organic acid conversion in one treatment tank can be performed simultaneously or sequentially.

The organic wastewater may be stored in a separate storage tank for a predetermined period of time before being transferred to the hydrolysis tank, and two or more storage tanks may be connected in series. The hydrolysis of the organic wastewater can proceed even while it is stored in the storage tank.

In the method of treating organic wastewater of the present invention, limonene is added to the organic wastewater before it is transferred to the hydrolysis tank or the hydrolysis tank. The limonene is added in an amount of 0.005 to 0.5 parts by weight, preferably 0.01 to 0.05 parts by weight, based on 100 parts by weight of the organic wastewater. If it is less than the lower limit, it is difficult to achieve a sufficient effect in the amount of solid matter reduction, organic acid production and methane gas production of the organic wastewater. If the upper limit is exceeded, the above effects are not increased any more, and the growth of microorganisms decomposing organic wastewater by the antimicrobial activity of limonene Can be suppressed.

Further, 0.01 to 2 parts by weight of at least one selected from a surfactant and a lipase may be added to the organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank together with the limonene.

Since the surfactant does not have a charge, it is preferable to use a nonionic surfactant capable of withstanding deactivation due to water hardness. For example, fatty acid alcohol ether, alkylpolyglucoside, ethylene oxide adduct and the like may be used.

The lipase is an enzyme that decomposes lipids and decomposes them into fatty acids and glycerin. Any animal, vegetable, bacterial or fungal lipase can be used, preferably those having high activity at 10 to 60 캜, more preferably, It is preferable that the activity is high at 10 to 20 占 폚, which is the temperature range of the organic wastewater of the hydrolysis tank, acid decomposition tank or methane production tank.

The method of treating organic wastewater according to the present invention is characterized in that the anaerobic digestion apparatus further comprises a microorganism propagation tank, and after the microorganism that hydrolyzes the organic wastewater is propagated in the microorganism propagation tank and then transferred to the hydrolysis tank or the hydrolysis tank It is preferable to supply the organic wastewater to the former organic wastewater. The rate of decomposition of organic matters such as carbohydrates, proteins and lipids is increased through the bioaugmentation in which the microorganisms are propagated in the microorganism propagation tank and then transferred to the storage tank or the hydrolysis tank, thereby increasing the amount of organic acid and methane produced .

In order to further promote bioaccumulation in the microorganism propagation tank, 0.1 to 10 wt% of a composition for the growth of a microorganism having a pH of 3 to 6, which comprises 1 to 30 wt% of an organic acid and 0.1 to 30 wt% of an amino acid, Can be added.

The organic acid is at least one selected from lactic acid, acetic acid, formic acid, propionic acid, sorbic acid, benzoic acid, salicylic acid and boric acid, preferably lactic acid or acetic acid. The organic acid is contained in an amount of 1 to 30% by weight, preferably 2 to 25% by weight, more preferably 3 to 20% by weight and most preferably 5 to 15% by weight. The microorganisms may proliferate and corruption or degeneration may occur. When the upper limit is exceeded, the cost is relatively increased, but the growth effect of microorganisms and the efficiency of degradation of organic matters are not improved.

The composition for liquid microbial growth has a pH of 3 to 6, preferably a pH of 3.5 to 5.5. When the upper limit is exceeded, the microorganism tends to proliferate as a liquid product stored and circulated at 1 to 35 ° C at room temperature, and the amount of organic acid added exceeds the upper limit value below the lower limit.

The amino acid may be a complex of at least one synthetic amino acid or a natural amino acid, and the natural amino acid may be a peptone or a yeast extract. The amount of the amino acid is 0.1 to 30% by weight, preferably 0.2 to 20% by weight, more preferably 0.3 to 15% by weight. When the upper limit is exceeded, The proliferation effect of microorganisms and the efficiency of decomposing organic matter may be lowered. Preferably, when a natural amino acid such as peptone or yeast extract is supplied, a vitamin B group such as riboflavin or thiamine necessary for microorganism growth can be supplied together, which is preferable.

If necessary, the monosaccharide or disaccharide may be added to at least one selected from the group consisting of fructose, glucose, galactose, maltose, sucrose and lactose, preferably fructose or glucose.

The liquid microorganism growth composition is added in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, more preferably 0.4 to 4 parts by weight, based on 100 parts by weight of the culture solution of the microorganism growth tank. It is difficult to achieve the effect of increasing the proliferation effect and the decomposition efficiency of the organic matter, and even if the upper limit is exceeded, the organic matter decomposition efficiency is not further increased.

The present invention relates to a hydrolysis tank for converting hydrocarbons, proteins and lipids of organic wastewater into monomers by hydrolysis; An acidogenic group in which the monomer is converted to an organic acid; And a methane generation tank in which methane is produced from the organic acid, characterized in that an input device for adding limonene to organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank is provided in the anaerobic digester, It is an anaerobic digester.

The anaerobic digestion apparatus may further include a storage tank for storing organic wastewater before being transferred to the hydrolysis tank.

The hydrolysis tank or the storage tank may further include an addition device for adding a surfactant or lipase.

Further, a microorganism propagation tank may be further provided for propagating a microorganism that hydrolyzes organic wastewater, and then supplying the microorganism to the hydrolysis tank or the storage tank.

The microbial growth tank may further include a bubble generator that uses a venturi effect to circulate the culture liquid through the microbial growth tank provided with the circulation pipe and to simultaneously perform the air supply and the dispersion of the culture liquid.

The bubble supplying device includes a depression formed in a surface of the bubble supplying device, the depression being formed in an inner surface of the depression, a first hole communicating with the depression and penetrating to the other surface of the depression, A first coupling member; And a second assembly formed with threads on the outer side so that one side is inserted into the depressed portion and screwed on the inner side surface of the depressed portion and having a second hole penetrating from one surface to the other surface and communicating with the first hole Wherein the suction groove is formed in the inner surface of the depression so as to extend along the depression direction of the depression, and the suction groove is communicated with the space between the depression and the second assembly And the second hole is narrowed in diameter in a direction from the other surface of the second coupling member to the first hole, and when the organic wastewater is supplied into the second hole and discharged to the first hole, air is sucked through the suction groove, The culture medium discharged into the first hole together with the organic wastewater and discharged to the first hole is supplied again to the microorganism breeding tank through the circulation pipe, Class, and it performs the distribution and circulation of the culture medium at the same time.

Figs. 1 to 3 are longitudinal sectional views showing the operation of the bubble generator, the liquid is shown by a solid line, and the gas is shown by a dotted line. 1, when a liquid is supplied to the tubular member 155 using a pump, the liquid is supplied to the second space (not shown) of the supply member 130 through the second supply hole 136 via the protruding member 150, The liquid is transferred to the liquid supply pipe 139. Further, the gas is transferred to the first space 137 of the supply member 130 through the first supply hole 134. That is, the liquid is supplied to the second space 139 of the supply member 130 at a constant flow rate, and the gas is delivered to the first space 137 of the supply member 130. Next, as shown in FIG. 2, a constant flow amount of the liquid supplied to the second space 139 of the supply member 130 is supplied to the second hole 127 of the second combination body 120. At this time, since the diameter of the second hole 127 of the second coupling member 120 becomes closer to the diameter of the first hole 117 of the first coupling member 110, the liquid at a constant flow rate becomes faster and the pressure becomes lower. Thus, as the pressure of the liquid decreases, the gas existing in the first space 137 of the supply member 130 is sucked through the suction groove 119 of the first assembly 110. As a result, the gas can be sucked in naturally using the venturi effect without a means for forcibly supplying the gas such as a compressor. 3, the liquid supplied to the second hole 127 of the second coupling body 120 and the gas sucked into the suction groove 119 of the first coupling body 110 pass through the first coupling body 110 In the space 114 between the depression 113 and the second coupling member 120 of the second coupling member 120. As such, when the liquid and the gas are mixed, very small bubbles can be generated. These bubbles are discharged through the first hole 117 of the first coupling member 110.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. It will be apparent, however, to those skilled in the art that these embodiments are for further explanation of the present invention and that the scope of the present invention is not limited thereby.

Experimental Example 1: Hydrolytic efficiency of organic wastewater according to temperature

Food wastewater having the composition shown in Table 1 discharged from the middle distillery of food waste materials in Ulsan was used for the following experiments.

division Total solids volatility
Solids Crude protein Crude fat Crude fiber Ash weight% 13.6 ± 0.5 11.4 ± 0.3 5.13 ± 0.2 3.07 ± 0.2 1.16 ± 0.2 2.36 ± 0.2

500 ml of the food wastewater was placed in a 1 l hydrolysis tank and maintained at 60 rpm for 3 days under the conditions of 12 캜, 18 캜 and 24 캜 for 3 days. Thereafter, the total solid content (TS), volatile solids The contents of crude protein, crude fat and crude fiber were analyzed by Kjeldahl protein determination method, ether extraction method and filtration method, respectively, and the results are shown in Table 2.

division Total solids volatility
Solids Crude protein Crude fat Crude fiber Ash 12 ° C 12.90 10.80 4.85 2.95 1.17 2.36 18 ℃ 12.40 9.90 4.45 1.85 1.17 2.34 24 ℃ 10.6 8.16 3.33 1.47 1.16 2.34

The hydrolysis of food wastewater by temperature showed a decrease of about 28% in volatile solids and about 20% in total solids content at 24 ° C, but the volatile solids and total solids content decreased about 5% at 12 ° C .

At 24 ℃, more than 50% of the fat was decomposed. However, as the temperature decreased, the decomposition rate of the fat rapidly decreased. At 12 ℃, only about 4% of the fat was decomposed and more than 90% of the fat remained.

Experimental Example 2: Hydrolytic efficiency of surfactant and lipase added to organic wastewater according to temperature

D-limonene alone or a mixture of limonene and a nonionic surfactant (IC Chem, model: ISODOL LA7) was added to the food wastewater of Experimental Example 1 at a rate of 60 rpm for 3 days at 12 캜, After the decomposition, the total solid content and the volatile solid content were measured and shown in Tables 3 and 4.

division Total solids
(%) Volatile solids
(%) Volatile solids / total solids
(%) Before processing 16.55 14.83 89.60 No additives 16.15 14.42 89.29 Limonene 100ppm 15.37 13.63 88.63 Limonene 200ppm 14.52 12.78 88.02 Limonene 300ppm 14.35 12.62 87.94

The decrease of volatile solid content and total solid content in the non - addition group at 12 ℃ was almost insignificant, but the volatile solid content and the total solid content decreased and the volatile solid content ratio to the total solid content decreased in proportion to the addition amount of limonene.

The amount of limonene added was fixed to 300 ppm and the addition of a nonionic surfactant was further performed to confirm the change of the volatile solid content and the total solid content after hydrolysis at 12 rpm for 3 days at 60 rpm under the same conditions as above.

division Total solids
(%) Volatile solids
(%) Volatile solids / total solids
(%) Before processing 16.55 14.83 89.60 Limonene 14.35 12.62 87.94 Limonene +
Nonionic surfactant 100 ppm 14.26 12.48 87.52 Limonene +
Nonionic surfactant 150 ppm 14.15 12.37 86.81 Limonene +
Nonionic surfactant 200 ppm 14.06 12.11 86.13

When the nonionic surfactant was added together with limonene, volatile solids and total solids were decreased in proportion to the addition amount, and the ratio of volatile solids to total solids was also decreased.

Experimental Example 3: Methane Production Rate and Yield by Addition of Surfactant

60 ml of the food wastewater of Experimental Example 1 and 340 ml of the anaerobic digestion sludge obtained from Ulsan Food Waste Intermediate Treatment Plant were mixed and 400 ml of the mixed solution was added to the 1 l hydrolysis tank and maintained at 18 rpm for 3 days at 60 rpm The amount of methane gas was measured. Table 5 shows the methane production rate and yield of the limonene or limonene of Experimental Example 2 and the sample to which the nonionic surfactant was added.

division Methane production rate
(CH ₄ ml / mgVS) Relative methane production No additives 0.434 100.0% Limonene 300 ppm 0.496 112.5% Limonene 300 ppm +
Nonionic surfactant 200 ppm 0.607 128.5%

Experimental Example  4: Methane production rate due to the increase of organisms

60 ml of the food wastewater of Experimental Example 1 and 340 ml of the anaerobic digestion sludge obtained from the food waste intermediate treatment company in Ulsan were mixed and the microorganisms having high hydrolysis activity were separated at the low temperature separated by the intermediate treatment company in the winter After culturing in a microbial growth apparatus at 30 ° C for 24 hours, a culture solution having a total bacterial concentration of 10 ⁸ CFU / ml or more in the cultured medium was prepared, 10 ml of the culture solution was added, and the mixture was maintained at 18 ° C for 3 days at 60 rpm And the amount of methane gas generated thereafter was measured (Sample 4-1).

5 ml of a liquid phase microorganism growth composition having pH 4.5 in which lactic acid, a yeast extract having a natural amino acid content of 40% by weight and water at a weight ratio of 20: 50: 30 was added to 100 ml of the mixture of the food wastewater and the anaerobic digestion sludge And cultured at 30 ° C for 24 hours to prepare a culture solution having a total bacterial concentration of 10 ⁸ CFU / ml or more in the cultured medium. 10 ml of the above culture solution, 60 ml of food waste water of Experimental Example 1, and 340 ml of anaerobic digestion sludge obtained from Ulsan Food Waste Intermediate Treatment Plant were mixed and maintained at 18 rpm for 60 days at 60 rpm to measure the amount of methane gas generated (Sample 4-2).

division Methane production rate (CH ₄ ml / mgVS) No additives 0.357 Sample 4-1 0.516 Sample 4-2 0.623

100: bubble generating means 110:
113: depression 114: space
115: thread 117: first hole
119: Suction groove 120: Second coupling body
125: thread 127: second hole
127a: Step 129:
130: supply member 133: outer wall
133a: first through hole 134: first supply hole
135: inner wall 135a: second through hole
136: second supply hole 137: first space
139: second space 140: first sealing means
145: second sealing means 150: projecting member
153: first flange 155: tubular member
157: second flange 160: flat face
165: Dowel groove 170: Rotation means

Claims (10)

A hydrolysis tank which hydrolyzes carbohydrates, proteins and lipids of organic wastewater into monomers; An acidogenic group in which the monomer is converted to an organic acid; And a methane generation tank in which methane is generated from the organic acid, the method comprising the steps of:
Wherein the limonene is added to the organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank.
The method according to claim 1, wherein the limonene is added in an amount of 0.005 to 0.5 part by weight based on 100 parts by weight of the organic wastewater.
The method of treating organic wastewater according to claim 1, wherein 0.01 to 2 parts by weight of at least one selected from a surfactant and a lipase is further added to the organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank.
The method according to claim 1, wherein the anaerobic digester further comprises a microbial growth tank, wherein the anaerobic digestion apparatus further comprises a microbial growth tank for growing microbes that hydrolyze organic wastewater in the microbial growth tank, Wherein the organic wastewater is supplied to the treatment tank.
5. The method according to claim 4, wherein 0.1 to 10 parts by weight of a composition for the growth of a microorganism having a pH of 3 to 6, which comprises 1 to 30% by weight of an organic acid and 0.1 to 30% by weight of an amino acid, is added to 100 parts by weight of the culture solution of the microorganism- ≪ / RTI >
A hydrolysis tank which hydrolyzes carbohydrates, proteins and lipids of organic wastewater into monomers; An acidogenic group in which the monomer is converted to an organic acid; And a methane generation tank in which methane is generated from the organic acid,
And an input device for adding limonene to the organic wastewater before being transferred to the hydrolysis tank or the hydrolysis tank.
The anaerobic digestion apparatus according to claim 6, further comprising a storage tank for storing organic wastewater before being transferred to the hydrolysis tank.
[7] The anaerobic digestion apparatus of claim 6, further comprising a feeding device for adding a surfactant or lipase to the hydrolysis tank or the storage tank.
9. The anaerobic digestion apparatus according to any one of claims 6 to 8, further comprising a microorganism propagation tank for propagating a microorganism that hydrolyzes organic wastewater, and then supplying the microorganism to the hydrolysis tank or the storage tank.
10. The microorganism-producing apparatus according to claim 9,
And a first hole communicating with the depressed portion and penetrating to the other surface, the first hole having a diameter smaller than the depressed portion, the first depressed portion being formed in the depressed portion; And a second assembly formed with threads on the outer side so that one side is inserted into the depressed portion and screwed on the inner side surface of the depressed portion and having a second hole penetrating from one surface to the other surface and communicating with the first hole And a bubble generating means
A suction groove is formed in the inner side surface of the depression so as to extend along the depression direction of the depression, the suction groove communicates with the space between the depression and the second combination body,
The second hole is narrowed in the one surface direction from the other surface direction of the second coupling member,
Air is sucked through the suction groove and discharged to the first hole together with the organic wastewater when the organic wastewater is supplied to the second hole and discharged to the first hole,
Wherein the organic wastewater discharged into the first hole is supplied again to the microorganism breeding tank and is further provided with a bubble generator that simultaneously performs air supply and dispersion and circulation of the organic wastewater.

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