KR100747682B1 - Method for treatment of livestock excrements using thermophilic aerobic fermentation, lime solidification and separation by reverse osmosis membrane - Google Patents

Abstract

A method for treatment of livestock excrements, which can always maintain the treated water quality within an effluent quality standard range, and produces a liquid fertilizer, a lime treatment fertilizer and a high concentration liquid phase fertilizer by thermophilic aerobic fermentation, solidification and reverse osmosis membrane separation of the livestock excrements respectively, is provided. A method for treatment of livestock excrements comprises: a thermophilic aerobic fermentation step; a chemical coagulation process using lime; and a physical purification process using reverse osmosis membrane separation. The thermophilic aerobic fermentation step comprises passing the livestock excrements through an excrement storage tank and a thermophilic aerobic fermentation equipment, and discharging a fermented liquid into a fermented liquid storage tank. The chemical coagulation process using lime comprises discharging a material stored in the fermented liquid storage tank through the thermophilic aerobic fermentation step into a filtrate storage tank through a mixing tank, a first coagulation tank, a dewatering equipment, a second coagulation tank, and a dewatering equipment. The physical purification process using reverse osmosis membrane separation comprises passing a filtrate through a reverse osmosis membrane separation equipment and a concentrate storage tank.

Description

Method for treatment of livestock excrements using thermophilic aerobic fermentation, lime solidification and separation by reverse osmosis membrane}

1 is a flow chart of a method for treating livestock wastes according to the present invention.

2 is a flowchart showing a biological oxidation process in a high temperature exhalation fermentation apparatus.

3 is a flow chart showing a chemical coagulation process in a lime solidification plant and dehydration apparatus.

4 is a flowchart showing a physical purification process in a reverse osmosis membrane separation apparatus.

5 is a graph showing the effect of rota-virus killing according to the treatment time of the high-temperature exhalation fermentation apparatus.

6 is a graph showing O-157 virus killing effect according to the treatment time of the high-temperature exhalation fermentation apparatus.

7 is a graph showing Salmonella, TGE, PED virus inactivation effect.

8 is a fluorescence picture of Cryptosporidium parvum before and after the high temperature aerobic fermentation treatment.

The present invention combines livestock manure with a biological oxidation process (hot aerobic fermentation), a chemical coagulation process (lime solidification) and a physical purification process (reverse osmosis membrane separation). The biological oxidation process uses a high-temperature aerobic fermentation device operating at a high temperature of 50 ~ 60 ℃ to promote the killing of pathogenic microorganisms and organic decomposition, and to produce lime-treated fertilizer by using lime for chemical coagulation and dehydration process. The removal of SS, chromaticity and organics improves the efficiency of the physical refining process. In the refining process, livestock manure is recycled by producing concentrated liquid fertilizer from residual organics and nitrogen.

The treatment of animal waste is different depending on the species, but it can be largely divided into a purification method and a resource method. As a method of purifying treatment, aerobic anaerobic and liquid corrosion are used. However, due to the high content of organic matter and nutrients, it is practically impossible to purify the wastewater by applying general wastewater treatment technology. Is facing a difficult situation to deal with regulatory concentrations.

   Meanwhile, the high temperature aerobic digestion method using heat energy generated by microbial reaction without additional heat supply from the outside as a treatment method for wastewater containing high concentration of organic material has been studied as part of the purification method of high concentration organic wastewater since the 1970s. It has been progressed, but due to the lack of various control technology, it is not applied in actual field.

  Existing recycling policies were mainly provided to individual farmers in the form of liquid and composting facilities funds. These policies were raised due to insufficient farming skills of individual farmers and insufficient processing capacity. There is a problem such as an increase in the cost of dumping offshore. In addition, the existing livestock wastewater treatment policy suffers a lot of difficulties due to the absence of a purification process that can properly treat animal waste. In this regard, the government proposed a plan to co-process by region by considering the above items in order to treat animal waste, which is the main source of water pollution. However, due to the limitation of the processing process, the existing joint treatment method cannot handle all slurry of animal waste in farms, but only the high water is processed due to the limitations of the collection system and the processing method, and the outbreak of animal infectious diseases occurs periodically. Due to the influx of disinfectants used in the process, the foaming efficiency and the killing of microorganisms cause problems such as drastically deteriorating treatment efficiency. However, there is a need for early development and application of processes that can be efficiently and reliably resourceized and treated.

In addition, as the law on livestock wastewater is strengthened, manure is composted using moisture control materials such as sawdust, and urine is purified by biological treatment such as activated sludge method. Recently, however, farms that rely on ocean dumping for a large amount of livestock wastewater are increasing due to a relatively long time treatment, a lack of operating technology and a burden of treatment costs. In foreign countries, livestock manure is treated with organic waste such as sewage sludge using stabilization, a method of waste treatment, to produce and utilize soil improvers and organic fertilizers. However, in the case of lime stabilization method, when the injected sludge has a water content of 75 to 85% (solid concentration of 15 to 25%), it is applicable to most livestock manure discharged in Korea containing 75 to 90% water as an applicable method. It is difficult to apply. Therefore, for the livestock manure having a water content of more than 85%, lime stabilization methods have been developed, which have secured hazards and safety.

  Accordingly, the present invention has been developed as an economical and efficient resource recycling process using a high-temperature aerobic fermentation, a chemical coagulation process using lime and a physical purification process using reverse osmosis membrane separation, which has high organic matter removal effect as a biological oxidation process in the treatment of animal waste.

High temperature aerobic digestion technology means maintaining the high temperature fermentation process by using the heat generated when the high temperature aerobic microorganisms digest the organic matter inside the fermentation apparatus. This high temperature aerobic digestion technology is largely applied to the field in two forms, one of which is a system in which organic matter is decomposed while oxygen is supplied at the same time as mixing and mixing in the reactor by installing a self-acting aeration / stirrer on the side wall of the reactor. One is to supply oxygen while circulating the lower inner water to the upper by the circulation pump installed outside the reactor. The key to this technology is to fine tune the oxygen supply method to keep the growth of the microorganisms at their maximum. The high temperature aerobic digestion method mainly utilizes high temperature microorganisms, and it is very important to maintain it at 55-65 ℃. In Korea, since the late 1980s, the characteristics of photosynthetic microorganisms have been used for livestock manure to increase the reaction temperature at high temperature (Thermophilic) within a short reaction time, and to raise the temperature of the livestock manure to regenerate it in liquid ratio. Ongoing research has resulted in a reaction time of less than 4 days and a system for producing high quality liquid fertilizers.

Accordingly, an object of the present invention for solving the above-mentioned conventional problems is to provide a method of treating livestock wastes using a chemical coagulation process using high temperature aerobic fermentation and lime and a physical purification process using reverse osmosis membrane separation.

The present invention for achieving the above object is characterized by using a chemical agglomeration process using high temperature aerobic fermentation and lime and a physical purification process using a reverse osmosis membrane separation.

Another aspect of the present invention, by using a high-temperature exhalation fermentation apparatus and a lime solidification device to maintain a high temperature by the self-heating of microorganisms without external heat source supply, stabilization due to the addition of the pathogenic microorganisms and water in the animal feces by stabilizing By killing the causing microorganisms, animal feces can be produced as a stable liquid fertilizer and lime-treated solid fertilizer.

Another aspect of the invention is characterized in that the high temperature maintenance by self-heating of the microorganism is maintained at about 50 ~ 60 ℃.

Another aspect of the present invention, the stabilization due to the addition of lime is characterized in that the pH 12 or more.

Another aspect of the present invention, by introducing lime and inorganic coagulant and polymer coagulant as a dehydration adjuvant to the treated water treated with high temperature aerobic fermentation induces the enlarging of particulate matter and using the solid-liquid separator to utilize the solid as a lime treatment fertilizer The releasing solution is characterized in that heavy metal concentration is suppressed during the production of concentrated liquid fertilizer by reverse osmosis membrane separation process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart of a method for treating animal wastes according to the present invention, and FIG. 2 is a flowchart showing a biological oxidation process in a high temperature expiratory fermentation apparatus.

High-temperature aerobic digestion kills pathogenic microorganisms due to the high temperature retention characteristics, and solves the concern about pathogenic microorganisms when using livestock waste.

In the high temperature aerobic fermentation system, the biological oxidation process is carried out by feeding the animal waste stored in the wastewater storage tank into the high temperature aerobic fermentation system (TAO system), which is a biological treatment process, without the pre-treatment, and simultaneously performing strong mixing and aeration. Induces a self-heating reaction. In this reactor, most pathogenic microorganisms are killed by the maintenance of high temperature due to self-heating, and the pH rises due to the generation of ammonia by the removal of organic substances and decomposition of protein components by high temperature microorganisms. Nitrogen is removed by degassing. A pump is installed inside the high temperature exhalation fermentation system to apply air automatically by the pressure difference through suction of internal liquid. The upper part of the reactor is attached with a propeller defoaming device to remove the bubbles generated by the air injection.

  The high temperature aerobic fermentation system is a batch type high temperature microorganism using high concentration (more than BOD 30,000mg / L) as a substrate to reach 60 ℃, which is the killing temperature of pathogenic microorganisms on the first day of reaction, 100% killing pathogenic microorganisms. The killing of pathogenic microorganisms acts as an important factor in land reduction of the produced liquor.

  When the liquid ratio produced by the high temperature exhalation fermentation equipment is not available, the problem of the imbalance requires the purification process. Most of the livestock manure that occurs in breeding farms is discharged in the form of slurry, which is very high. In the existing livestock wastewater treatment, the influent wastewater is separated by solid-liquid separation by centrifugation, and it is processed through chemical flocculation / dehydration and anaerobic digestion and then activated sludge process. The problem here is that when agglomerates the raw water, which is the main ingredient, excessive foaming occurs and a large amount of polymer material is contained in the desorption filtrate after dehydration. It will cost processing. The high-temperature breathing fermentation device performs an excellent function as pretreatment during runaway manure purification process by lowering the molecular weight of the polymer material, and has the effect of reducing the amount of foaming and injection during chemical aggregation.

3 is a flow chart showing a chemical coagulation process in a lime solidification plant and dehydration apparatus.

The basic purpose of lime stabilization is to prevent the activity of pathogenic microorganisms. This depends on the pH level and the pH duration of the reactants rather than on the amount of lime used. If the pH is maintained above 12 hours for 2 hours, pathogens are sterilized and the activity of decaying microorganisms is suppressed. Preferred pH of the reactants is to follow EPA's Process to Significantly Reduce Pathogens (PSRP), which are maintained above 12.5 or above pH 12.

  In addition, lime itself is absorbed by plant nutrients, but it improves the physicochemical properties of soils by increasing the osmoticity of soils, increasing the water holding capacity of soils, coagulating soils, decreasing cohesiveness, replacing bases, and eliminating year. Enhances the absorbency by strengthening the vitality of the roots, and also eliminates or repels various harmful conditions that inhibit the growth of crops, promotes decomposition of organic matter, mineralizes organic nitrogen and accumulates ammonia nitrogen to Direct and indirect effects are reported to be large.

Lime solidification removes organic matter, suspended solids and heavy metals contained in the high temperature aerobic liquor by using lime, inorganic coagulant and polymer coagulant to improve the treatment efficiency of the latter membrane separation process and to remove pathogenic microorganisms that are not killed in high temperature aerobic treatment. Lime is added to increase the pH to 12 to inactivate and stabilize the remaining organics.

  Agglomeration sedimentation is a process of removing dissolved or suspended solids in water by injecting a chemical. Coagulation sedimentation can often be thought of as three steps: coagulation by chemical injection, coagulation of the fine flocs produced, and precipitation of large flocs formed. Among these, the flocculation step refers to the formation of flocs that can be easily precipitated by destabilizing fine colloidal particles, dissolved ions, or larger suspended solids by injecting a drug, that is, a flocculant.

Referring to FIG. 3, the lime solidification facility and the dehydration device according to the chemical flocculation process are facilities for producing lime-treated fertilizers by solidifying high concentrations of suspended solids contained in livestock manure. It consists of a filtrate reservoir, a secondary flocculation tank and a filter press. In order to induce alkaline hydrolysis of TAO treated water, the coagulation sample adjusting tank raises the pH from 9.0 to 12.0 by adding slaked lime, and induces the formation of flocs by adding iron salt and polymer coagulant. Perform solid-liquid separation.

Reverse osmosis (RO) membranes used in reverse osmosis, one of the membrane separation processes, can be used as modules such as ultrafiltration, which are tubular (T), micro hollow fiber (HFF), flat (PF) and spiral ( SW). These forms are essentially the same as ultrafiltration. The RO membrane has pores as small as 0.0005 μm excluding ions and operates at a pressure of 200 to 600 psi. The operating speed of the RO membrane is typically in the range of 3 to 20 g / sfd.

Referring to FIG. 4, which is a flowchart illustrating a physical purification process in the reverse osmosis membrane separation apparatus, the reverse osmosis membrane of the reverse osmosis membrane separation apparatus according to the physical purification process is a selective permeation membrane for removing dissolved solids such as metal salts. The device consists of a pretreatment pump and a high pressure pump for injecting pressure above osmotic pressure and separates the treated and concentrated water by running a pressure pump. Membrane materials are cellulose acete and aromatic polyamide. The membrane replacement cycle is about 2 years, and when the water volume decreases, the membrane is cleaned with a washing solution and the tubular or plate membrane is scraped off with a brush or the like. Replace the membrane when cleaning is no longer effective. Theoretically, the water pumped by the R / O system is recovered and processed 100%, but due to contamination problems, 15-25% of the inflow is recovered as concentrated water and the system consists of multiple stages. The typical reverse osmosis membrane has a pore size of 0.0005 to 0.002 μm and a pressure of 300 to 400 psi (20 to 27 atm) to prevent contamination, pretreatment of the influent to maintain turbidity below 1 NTU. The pretreatment facility requires chemical treatment, sedimentation and filtration facilities, and the final cartridge filter is 5μm in size.

Livestock excretion is based on abundant nutrients, and various microorganisms are breeding. Among them, pathogenic microorganisms are included, and there is a problem in reusing sludge generated in livestock excretion treatment. The fermentation apparatus solves the problem of sludge reuse by stabilizing sludge by killing pathogenic microorganisms by maintaining high temperature by self-heating by using organic material of livestock excrement as energy source.

  High-temperature aerobic fermentation is operated in a batch type, inflow / outflow of the planned flow once a day. The temperature of raw water is 4 ℃ ~ 24 ℃, and after 24 hours, the internal temperature of the reactor rises to 60 ℃, and then maintains a constant temperature continuously. All pathogenic microorganisms are killed between 30 minutes and 120 minutes at a temperature of less than 60 ℃, 100% of pathogenic microorganisms are killed when liquefaction of livestock feces using the high temperature aerobic fermentation device.

 In the case of conventional lime stabilization methods, when the injected sludge has a water content of 75 to 85% (solid concentration of 15 to 25%), it is applicable to most livestock manure discharged in Korea containing 75 to 90% water as an applicable method. Although it was difficult to apply, it is a lime stabilization method that has been applied to livestock manure with a water content of 95% or more.

Example 1

Applicant prepared a livestock waste treatment model facility according to the above configuration, and experimented with a processing capacity of 5 m ³ / day for approximately 5 months. Referring to the flow chart showing the biological oxidation process in the high temperature expiratory fermentation apparatus according to Figure 2, the manure storage tank was treated with a stirring device as a volume of 37 m ^{3 with} a concentration of 5 to 8% solids, the transfer pump in the manure storage tank The high temperature exhalation fermenter was pumped at an air injection rate of 60 m ³ / hr and the operating temperature was 55 to 65 ° C. Manure input was 4.0 ~ 5.0 m ³ / day and manure discharge was 3.0 ~ 4.0m ³ / day.

The discharged liquid from the high temperature aerobic fermentation system is sent to the fermentation broth reservoir, and the fermentation broth is equipped with a stirring device and has a capacity of 37 m ³ .

The fermentation broth is sent from the fermentation broth to the mixing tank. The mixing tank is equipped with a stirring device, the capacity is 10 m ³ , the treatment is performed by adding 40 kg / m ³ of slaked lime and 5.0 kg / m ³ of iron salt. pH was treated with 12 ~ 12.5.

It was sent from the treated mixing tank to the primary coagulation tank using a transfer pump, which was equipped with a stirring device, the capacity was 6.0 m ^3, and the polymer was added 0.50 kg / m ³ . The treatment in the primary coagulation tank was sent back to the dehydrator for dehydration and back to the secondary coagulation tank. This secondary coagulation tank was equipped with a stirring device, the capacity was 10 m ³ and iron salt 5.0 kg / m ³ was added. Further 0.25 kg / m ³ of polymer was added. pH was treated with 10 ~ 10.5. Thereafter, after the dehydration process in the dehydrator was sent back to the filtrate reservoir with agitator.

From this filtrate reservoir it was sent to a reverse osmosis membrane separator using a transfer pump and then to a 37 m ³ concentrate reservoir with agitation.

Example 2 Analysis of Treated Water According to the Present Invention

Livestock excreta were collected from pig farms located in Gungchon-ri, Munmak-eup, Wonju-si, Gangwon-do, Korea. . The treated water generated at this time was analyzed according to the wastewater discharge standard of the public treatment plant. Effluent water quality standards, the BOD, CODcr, COD _Mn, SS, TN, TP, and is configured to measure the E. coli, the average concentration of the treated respectively _{BOD 16 ㎎ / L, COD Mn} 25 ㎎ / L, SS 2 ㎎ / L, TN 44 mg / L, TP 0 mg / L, and E. coli were not detected and showed good values suitable for the effluent water quality standards.

Comparison of Inflow / Outflow by Effluent Water Quality Standards  division BOD COD SS T-N T-P Escherichia coli inflow 35,000 25,877 40,927 4,864 1,082 47,837 outflow 16 25 2 44 0 voice Discharge standard 30 50 30 60 8 3,000

Unit: mg / L

Example 3 Pollutant Removal Efficiency

As a result of analysis using the same manure as above, the average BOD and CODcr concentrations of raw water were 35,000 mg / L and 25,877 mg / L, which were relatively higher than the concentrations introduced into the public treatment plant. The fact that the water quality is very high compared to the design concentration of the existing livestock wastewater public treatment plant is considered to reflect the concentration of the wastewater generated in the farmhouse.

Table 2 shows the concentrations and removal efficiencies of influent and unit processes. When the removal efficiency of each treatment unit process is expressed as the whole process, the removal efficiency is over 99%.

Pollutant Concentration and Treatment Efficiency division BOD5 CODMn SS TN TP Escherichia coli Influent (mg / L) (average concentration) 23000 ~ 44900 (34,540) 20,042 ~ 33,900 (25,877) 27,600 ~ 53,800 (40,942) 3,039 ~ 6,497 (4,864) 676-1,446 (1,082) 16,000 ~ 74,000 (47,837) TAO treated water Concentration (mg / L) 6,627--10,296 (8,286) 8,017 ~ 13,560 (10,039) 25,696 ~ 50,162 (38,117) 2,431 ~ 5,198 (3,892) 609-1,301 (974) voice efficiency(%) 76.01 61.21 6.90 20.00 10.00 100  Lime solidification primary Concentration (mg / L) 2,982 ~ 4,633 (3,729) 4,008 ~ 6,780 (5,019) 1,100 ~ 1,500 (1,042) 1,935 ~ 4,158 (3,113) 18--39 (29) - efficiency(%) 55.00 50.00 97.26 20.00 97.00 Lime solidification 2nd Concentration (mg / L) 895 ~ 1,390 (1,119) 2,004 ~ 3,390 (2,510) 100-300 (150) 100-300 (150) 1,848 ~ 3,950 (2,958) 5 ~ 10 (7) efficiency(%) 70.00 50.00 85.60 5.00 75.00 Reverse Osmosis Membrane Treatment Water Concentration (mg / L) 13-21 (16) 19--36 (25) 1 ~ 5 (3) 28-49 (44) 0 (0) voice efficiency(%) 98.50 99.00 98.66 98.50 99.99 100 Processing efficiency (%) 99.95 99.90 99.99 99.09 99.99 100

Example 4 Eradication of Pathogenic Bacteria of High-temperature Exhalation

 Livestock manure and livestock waste (respiratory secretions, urine and slaughtered feathers, hides, etc.) contain high concentrations of pathogenic microorganisms that are harmful to humans. The amount per area is also very high. Therefore, it must be managed efficiently for environmental pollution and public health. The reaction temperature in this system is operated at 55 ± 5 ° C. for more than 24 hours at a high temperature, so that the E. coli and the harmful pathogenic bacteria contained in the livestock manure are converted into clean liquid ratios. The experimental results are shown in FIGS. 5 to 7. Indicated.

In addition to the legal standard, maturation and the presence of harmful microorganisms are very important factors when using fertilizer fertilizer (liquid) and solid compost. Currently, C. parvum and G. lamblia are microorganisms that cause aquatic infectious diseases. C. parbium has been recognized as a major cause of aquatic infections since 1983. It is recognized as the most important pathogenic microorganism. It is also reported that there are at least 0.8 oocysts / L and 112.0 oocysts / L of C. farbium in the channel, which may present a risk of mass diarrhea. (Tsushima, 2001; LeChevallier, 1991; Rose, JB, et al 1991).

In general, cysts and oocysts of protozoa have a strong resistance to disinfectants, but in particular, C. farium Oocysts are known to be very resistant to chlorine disinfection. However, in WHO (1996) and Fujino, et al (2002), C. farbium and G. ramblia are heat-resistant, and C. farbium is sterilized for 55 seconds to 30 seconds and 60 degrees to 15 seconds. Reported inactivation. In the case of the liquid fertilizer treated using the high temperature aerobic fermentation system, it was possible to inactivate the microorganisms causing the waterborne infectious diseases to remove the secondary pollution caused by animal waste.

Example 5 Treatment Efficiency and Performance of Separation Method of Organics and Phosphorus Removal Using Lime Solidifying Device

The present invention stabilizes by raising the residual hardly decomposable organic material, color causing substances and pathogenic microorganisms which are not removed by the high temperature aerobic fermentation apparatus to pH 12 or higher using calcined lime, induces alkali hydrolysis and aggregates / removes heavy metals, SS and TP. It is a process for producing organic lime fertilizer. Table 3 shows the influent, treated water concentration and treatment efficiency of the lime solidification method. Each concentration of effluent shows high removal rates for SS, BOD and TP at BOD 1,119 mg / L, COD _Mn 2,510 mg / L, TN 2,958 mg / L, TP 7 mg / L, SS 150 mg / L.

Inflow / Outflow Concentration and Treatment Efficiency of Lime Solidification Equipment Item Influent (average concentration) Treated water (average concentration) Treatment efficiency (%) BOD ₅ 6,62710,296 (8,286) 8951,390 (1,119) 86.5 COD _Mn 8,01713,560 (10,039) 2,0043,390 (2,510) 76.0 SS 25,69650,162 (38,117) 100300 (150) 99.6 T-N 2,4315,198 (3,892) 1,8483,950 (2,958) 24.0 T-P 6091,301 (974) 510 (7) 99.3

As described above, the present invention can prevent the eutrophication of the water system by killing the livestock feces recognized as environmental pollutants at all times within the legal effluent water quality standards and killing pathogenic microorganisms by the high temperature aerobic fermentation treatment. It is possible to build a livestock waste treatment and reuse system that can promote circular eco-friendly agriculture by producing lime concentrate fertilizer and liquid fertilizer using reverse osmosis membrane separation by reducing liquid fertilizer and solidification. .

In addition, economically, by diluting raw water and treating pig manure using a simple process combination, it has the advantage of being economical, short in residence time, and less land area.

Claims (7)

A method for processing animal waste, comprising a chemical coagulation process step using high temperature aerobic fermentation step and lime and a physical purification process step using reverse osmosis membrane separation. The method of claim 1, wherein the high temperature expiratory fermentation step is discharged to the fermentation broth after passing through the feces storage tank and the high temperature expiratory fermentation device. According to claim 1, wherein the chemical coagulation process step using lime is a high temperature aerobic fermentation step through the material stored in the fermentation broth storage tank mixing tank, primary coagulation tank, dehydration device, secondary coagulation tank and dewatering device to the filtrate storage tank Characterized in that it is discharged. The method of claim 1, wherein the physical purification process step using the reverse osmosis membrane separation comprises a step of passing through the reverse osmosis membrane separation apparatus and the concentrate storage tank. It maintains high temperature by self-heating of microorganisms without using external heat source and stabilizes by adding lime by using high temperature aerobic fermentation device and lime solidifying device, and kills microorganisms present in animal wastes. How to switch to fertilizer. The method of claim 5, wherein the high temperature maintenance by self-heating of the microorganism is maintained at about 50 ~ 60 ℃. The method of claim 5, wherein the stabilization due to the addition of lime is characterized in that the pH 12 or more.

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