KR20020021289A - Method for treating a food waste and livestock wastes at the same time - Google Patents

Abstract

PURPOSE: A method for treating food garbage and livestock wastewater at the same time is provided which highly efficiently forms the food garbage and livestock wastewater into feed and compost respectively by simultaneously treating the food garbage and livestock wastewater through a single process. CONSTITUTION: The method for treating food garbage and livestock wastewater at the same time comprises the steps of removing salt by sorting and washing the food garbage; forming the food garbage into a slurry by crushing the salt removed food garbage; mixing the food garbage in the slurry state with animal excretions in a water collection tank; periodically spraying a mixed wastewater of the food garbage and livestock wastewater stored in the water collection tank onto the upper surface of sawdust inside a sawdust fermentation purification tank in which a contact filter medium tank is equipped at the lower part of a porous bottom surface, sawdust is filled in the upper part of the porous bottom surface, and external air is supplied through the contact filter medium and the porous bottom surface; composting the fermented materials by supplying air into the mixture as agitating a mixture of the sprayed food garbage and livestock wastewater with sawdust so that the materials are fermented; homogenizing a concentration of wastewater by storing washed water generated during washing of the food garbage and leaching filtrate produced from the contact filter medium tank of the sawdust fermentation purification tank; removing the floated scum by floating alien materials in the wastewater homogenized in a pressure flotation tank; and denitrifying the wastewater and treating residual contaminants by biologically treating the wastewater passing through the pressure flotation treatment.

Description

Method for treating a food waste and livestock wastes at the same time}

The present invention relates to a method for simultaneously treating food waste and livestock wastewater, and more particularly, by mixing food waste and livestock wastewater previously treated through an independent treatment system and treating each other in a single treatment system. The present invention relates to a method of mixing and treating food waste and livestock wastewater, which can increase the treatment efficiency by complementary action of food waste and livestock wastewater, and to simplify the treatment process and required equipment.

In recent years, with the overcrowding of the population and the rapid development of the industry, the amount of various wastes and wastewater is increasing, and the kinds thereof are also diversifying. Among these various kinds of wastes and wastewaters, especially the food waste discharged as a result of daily life and the livestock wastewater generated in the industrialized or large-scale livestock farms are seriously considered. Some of the representative treatments that have been made so far related to the disposal of garbage and livestock wastewater are as follows.

First of all, the most common form of disposal of food waste is landfill, which is becoming harder to secure landfills, and leachate is generated after landfill, causing secondary environmental pollution such as contaminating groundwater and soil. And, in order to treat the leachate generated in the landfill in order to eliminate the damage of such leachate there is a problem that takes a lot of equipment and treatment cost.

On the other hand, in view of the above problems pointed out in the landfill method, some methods of incineration of food waste are implemented. Food waste has a water content of 90% or more, which requires considerable fuel costs and incineration facilities. In addition, there is a disadvantage that air pollution caused by smoke, dust, dioxins, etc. generated during incineration.

As an effective treatment method of food waste, it is considered to recycle it as compost or feed, which requires strict separation discharge and rapid collection and transportation to prevent other foreign substances from being included. The situation is not properly performed, but in the summer, when the temperature is high, food waste is easily decayed or deteriorated, and there are many difficulties in treating it as a recycling resource for feed or compost.

Food waste is fed into livestock feed and recycled as food for livestock. This may be the case for direct feeding of livestock or as a supplementary feed, but this is only a small fraction of the total food waste generation.

On the other hand, in the treatment method for composting the food waste, as a bulking agent for controlling salt and water contained in the food waste, subsidiary materials such as sawdust or chaff are mixed with the food waste and fermented, which is a considerable amount of sawdust. It is known that the economy is inferior because of the difficulty in supply and demand of subsidiary materials such as sawdust. In particular, when the salt is composted in a state that is not properly removed, rather than inhibiting the growth of plants, salt control is a very important problem in the composting treatment of food waste, the food of our country shows a relatively high salinity Depending on the separate desalination process or excessive sawdust should be used, according to the composting of food waste there is a more difficult side.

Next, the livestock wastewater is a wastewater mixed with livestock manure and livestock wash water, and is a high concentration organic wastewater that depletes the dissolved oxygen in the discharge water system, lowering the self-cleaning ability of the stream, and inducing rapid reproduction of algae when it enters lakes or reservoirs. It acts as a serious pollutant such as eutrophication occurs. As a method of treating livestock wastewater, composting methods using sawdust, etc., storage liquid fertilization method, activated sludge method and anaerobic fermentation method are known, and although they are actually applied to some livestock farms, the processing efficiency is low and the processing cost is burdensome. It is not practical.

That is, because livestock wastewater mixed with manure and urine contains a large amount of organic solids, many chemicals must be used to separate these solids, and the separated solids are subjected to composting treatment, and the separated liquid is purified several steps separately. It must be treated, but the separation liquid itself is high in concentration and therefore requires a great deal of dilution and power for the titration.

One of the factors that makes composting of livestock wastewater difficult is that manure-mixed houses such as slurry pigs are stored for long periods of time before being transported to the composting facility. In this case, if the storage period before the treatment is long, the organic matter is decomposed in the anaerobic state during that time, the carbon that should be used as an energy source of fermentation microorganisms in the composting facility is insufficient, and thus the fermentation efficiency is reduced.

On the other hand, even if the livestock waste is completely decomposed biologically, COD is emitted more than 50mg / L. This is mainly due to the NBD component (natural organic substance is known to occur a lot in the natural state as a main component) does not affect the ecosystem. However, the current COD regulation of domestic livestock wastewater treatment plant is under 50mg / L, so much facility investment and chemicals are consumed for its treatment.

As mentioned above, the existing food waste treatment method or livestock waste water treatment method has been proposed or tried in various forms, but it is not yet satisfactory in terms of economic efficiency, treatment cost, and treatment efficiency. Research and development is desired.

On the other hand, Korean Patent Publication (Patent No. 200031) discloses a compost fermentation agent using a food waste, a method of manufacturing the same and a method for composting livestock wastewater using the same, which is organic matter decomposition microorganism Pits present in the culture are mixed with a bulking agent or fermentation enzyme to mix the calcium compound and fermentation in an aerobic fermenter followed by an anaerobic fermentation step to obtain a compost fermentation agent.

However, the above patent requires a pit and a calcium compound, resulting in an increase in food processing costs, and also requires an aerobic fermentation process and an anaerobic fermentation process to be performed as subsequent processes. This is being pointed out.

In addition, although the patent discloses that the compost fermentation agent obtained from the food waste can be used for composting livestock wastewater, there is no specific description regarding the composting of livestock wastewater.

The inventors of the present invention can improve the processing efficiency through the complementary action when simultaneously processing food waste and livestock wastewater that has been treated through each treatment system through a single treatment system. Development of the present invention has been undertaken and many experiments have led to the completion of the present invention with useful and satisfactory results.

That is, food waste is acidic, while livestock wastewater is alkaline, so mixing it with each other can maintain neutrality, and salt and spicy are removed while washing food waste, and the removed salt flows into the wastewater treatment process. It is possible to solve the problem of salinity in composting facilities, salt and spicy taste in feeder facilities, and the lack of calories in fermenters when treating livestock wastes alone. By maintaining the / N ratio, the fermentation can be activated, and the problem caused by the lack of external carbon can be used to clean up the leaching filtrate of the sawdust fermentation purification facility. The odor generated is connected to the air supply line of the sawdust fermentation plant and sent to the fermenter. As the premise gets the degradation effect of the odor substances by microbial fermentation it would be able to solve the odor problem was trying repetitive experiments.

Thus, the present invention is a simple equipment and through the complementary action of the physical and chemical properties of each of the food waste and livestock waste water by simultaneously processing the food waste and livestock waste water that was conventionally treated through each treatment process through a single process and A simple treatment process aims to provide a mixed treatment method of food waste and livestock wastewater which enables high efficiency food waste feed and livestock waste composting.

1 is a process step of treating food waste and livestock wastewater by the method of the present invention.

The object of the present invention is to remove the salt by screening and washing the food waste, and to feed the food waste in the salt-free state, the food waste in the salt-free state of the food waste is not pulverized food waste And slurrying, and mixing and mixing food slurry in the slurry state into the manure manure stored in the water collection tank, and having a contact media (media) bath at the bottom of the porous bottom surface and having a bottom surface. The furnace is filled with sawdust and periodically spraying the mixture of food waste and livestock waste water stored in the sump to the top of the sawdust inside the sawdust fermentation septic tank is supplied air through the contact filter tank and the bottom surface from the outside, the sawdust layer While stirring the mixture of food waste and livestock wastewater sprayed on the top and sawdust Supplying fish to allow fermentation to occur, and storing the leaching filtrate from the contacting medium of the washing water and the sawdust fermentation septic tank generated during the washing of the food waste and homogenizing the concentration of the waste water, and pressurizing It consists of the step of removing the scum injured by floating the foreign matter in the homogenized waste water in the flotation tank and the biological denitrification treatment of the waste water subjected to the pressure injury treatment.

Looking at each step in the method of mixing the food waste and livestock wastewater by the method of the present invention in more detail as follows.

First, among the collected food wastes, those that are relatively well collected and kept in good condition and those that are separated and poorly collected are separately washed and sorted and then separated and fed into high quality food waste. Do

Such feed treatment is performed by dry feed and wet feed processes after washing, selecting and removing foreign matters unnecessary for feed, such as dish towels, towels, or vinyl, which are included in food waste.

In more detail, the dry feed process is washed and dehydrated to remove salt and spicy taste of food waste, and then cooked for 30 minutes at a temperature of 90-110 ° C. in a cooking facility to minimize nutrient breakdown during processing. After drying at 90 ° C. for 1 hour, the water content was lowered to 10% and cooled by a rotary method to adjust the water content to about 6%. Finally, the pulverized using a hammer mill to filter the vibrating sieve to remove foreign matters to use as a raw material of the blended feed or feed it to livestock farms to mix with the existing blended feed, the wet feed process is to use food In order to remove the salt and spicy taste of the trash, it is crushed in the state of water after washing, dehydration, and then added by heating, sterilization or organic acid to kill the decayed bacteria and mixed fermentation with compound feed or agricultural by-products.

On the other hand, composting treatment is performed on the food waste of the state which is difficult to feed. This composting treatment of food waste is to remove the foreign matter, such as dishcloth, towels, rubber gloves or wooden chopsticks, and to lower the salt concentration through the screening and washing process similar to the feed treatment. In order to encourage the promotion of food wastes with low salt concentrations, the government authorities replaced the use ratio of food wastes, which are defined as 30% or less of raw materials in the current composting process standards, with salt concentration standards. It is desirable to wash food waste.

Next, the food waste, which is difficult to feed in the washed and selected food waste, is finely pulverized by a crusher in the crushing process to become a slurry state (porridge).

Subsequently, the slurry of food waste is mixed with the manure manure transferred from the barn in the sump and stored. At this time, the mixture of livestock waste and food waste stored in the sump is discharged and sprayed every 3 days at the sawdust fermentation septic tank, which is a facility for the subsequent process, so that the capacity of the sump is preferably designed to store more than 5 days. Do.

Next, the mixture of the livestock wastewater and food waste stored in the sump is put into a sawdust fermentation septic tank filled with sawdust therein to compost and purify by fermentation. At this time, the sawdust fermentation septic tank is provided with a contact medium (media) tank at the bottom centered on the porous bottom surface of the bottom, the sawdust is filled in the bottom surface of the sawdust fermentation through the contact filter tank and the bottom surface from the outside blower With this structure, a mixture of livestock wastewater and food waste, which is an organic wastewater containing a high concentration of organic material (SS) sprayed to the top of sawdust, is simultaneously aerobic fermentation and purification by microorganisms.

The process physically and biologically treats a mixture of livestock wastewater and food waste without using chemicals to produce solids with high quality compost, and contaminants in the leachate collected by flowing down through the sawdust fermentation layer. The source of contamination is minimized by treatment by microorganisms such as catalytic oxidation in silver contact media.

The sawdust fermentation purification process in the present invention is not a way to mix the livestock wastewater and sawdust and then put it into the fermentation tank, but to stir while spraying the mixed wastewater of the livestock wastewater and food waste to the sawdust pre-loaded inside the sawdust fermentation septic tank The sawdust fermentation purification device used in this manner has already been filed by the present applicant (application number: Patent Application No. 2000-45974).

In the sawdust fermentation purification process of the present invention, about 30% of the mixed wastewater input is generated as a filtrate, and the treatment water quality is better than the filtrate dehydrated after chemical treatment, and thus the treatment cost can be reduced.

Looking at the mechanism that the food waste in the sawdust fermentation purification process and livestock manure (livestock wastewater) mutually complementary action to promote the fermentation reaction for composting as follows.

Cellular components of microorganisms are mainly carbon, nitrogen, oxygen and phosphorus, especially carbon and nitrogen require large amounts. Therefore, the reaction rate in the fermentation reaction is greatly influenced by the carbon and nitrogen ratio (C / N) present in the organic matter and is known to show a large difference in the C / N ratio required according to the type of microorganism.

In general, the compostable C / N ratio is less than 50, and the optimum C / N ratio range is known to be about 10-30, although there are some differences depending on the operating conditions. When the C / N ratio is high, the decomposition rate is slowed due to the lack of nitrogen source, so a long time is required for composting, and the pH is lowered due to the formation of lower fatty acids as it is partially anaerobic. On the contrary, when the C / N ratio is low, the reaction time may be shortened, but ammonia is excessively generated, resulting in low decomposition rate and loss of nitrogen.

In the sawdust fermentation purification process of the present invention, the carbon source consumed by anaerobic decomposition in the long-term storage of the livestock wastewater can be supplemented from food waste to maintain the appropriate C / N ratio in the range to maximize the decomposition rate.

On the other hand, the fermentation is completed in the sawdust fermentation septic tank can be supplied to farms and the like as organic fertilizer.

Next, the leaching filtrate discharged from the washing wastewater and sawdust fermentation septic tank generated during the washing process of food waste is transferred to the filtrate storage tank and homogenized. Since the leaching filtrate from the sawdust fermentation tank has already undergone one stage of purification, most of the organic matter has been removed, so the concentration of organic matter is relatively low and the concentration of nitrogen is relatively high.

Therefore, when biological treatment of the leaching filtrate in the above state through the denitrification process that is a subsequent process, there is a problem that a separate external carbon source must be added because normal treatment is difficult due to the imbalance of nutritional balance.

However, in the present invention, the leaching filtrate is not directly transferred to the denitrification process, but is mixed with the washing wastewater of the food waste having a high concentration of organic material and low nitrogen, so that a homogenization treatment is performed, thereby providing an additional carbon source. This has the advantage of eliminating the need to supply.

Next, the mixed wastewater of the homogenized washing water and the leaching filtrate in the filtrate adjusting tank is subjected to flotation and separation of foreign matters through a pressurized flotation process. That is, the washing water of the food waste contains a large amount of oil components and contaminants, which are floated to the surface in the pressure flotation tank to be removed as scum, this separated scum is sent to the livestock waste water storage tank to be processed.

As a final process, the mixed wastewater in which the pressure flotation is completed is discharged through a biological treatment including a denitrification process. That is, the leaching filtrate from the sawdust fermentation septic tank and the food waste washing waste water contain a large amount of organic contaminants. Therefore, biological treatment such as activated sludge process should be performed. It is discharged after denitrification so that the nitrogen component (typically 60ppm or less) within a proper standard is passed through the biological treatment included.

An embodiment of the method of the present invention will be described with reference to the series of process flow charts shown in FIG.

First, the food waste is washed with water and the removal of foreign matter that is impossible to feed and compost by washing and sorting, and also to wash the salt, spicy taste, spoiled substances and toxic components. At this time, fresh and high-quality food wastes are sorted separately and sent to a wet feed process or dry feed process for feed treatment.Other food wastes that are impossible to feed can be pulverized to become a slurry state and then into a collecting tank. It is stored in and treated with livestock wastewater.

On the other hand, the washing wastewater generated in the washing process is mixed with the leaching filtrate of the sawdust fermentation purification plant is treated.

The washed and sorted food waste is subjected to a wet feed process and a dry feed process according to the use of the feed. In order to increase the safety, it is heated and sterilized to kill the decayed bacteria, and to supplement the insufficient nutrients of food waste feed, the mixed feed and agricultural by-products are mixed and fermented and used as feed in livestock farms.

The dry feed process dehydrates food waste from washing and screening process, and then increases the temperature at 90 ~ 110 ℃ in the cooking facility to increase the temperature for 30 minutes to minimize the nutrient destruction according to processing, and secondly, it is dried at 90 ℃ for 1 hour. Lower the water content to 10% or less and cool it by rotary method so that the water content is about 6%. Subsequently, it is pulverized using a hammer mill and the foreign matter is removed with a vibrating sieve to be used as a raw material for blended feed or supplied to a livestock farm and mixed with an existing blended feed.

On the other hand, the livestock manure generated in the barn is mixed with the food waste in the form of slurry after being crushed after washing and sorting and stored in the sump tank.

The mixed wastewater of food waste and livestock manure stored in the sump is supplied to the sawdust fermentation septic tank equipped with a contact filter tank capable of purifying treatment with a contact filter at the bottom thereof.

The organic matter in the mixed wastewater introduced into the sawdust fermentation septic tank is decomposed by aerobic microorganisms, and the solid material in the mixed wastewater is mixed with the sawdust layer of the sawdust fermentation septic tank and fermented for about 6 months, followed by a packaging process. It is sold as an organic fertilizer.

Then, about 30% of the mixed wastewater introduced into the sawdust fermentation septic tank is generated as a leaching filtrate and is stored in the filtrate storage tank together with the food waste washing water to be homogenized and transferred to the pressure flotation tank.

Subsequently, the wastewater treated in the pressure flotation tank is discharged to the outside after treating the concentration of untreated residual pollutants and nitrogen below a proper standard by a biological treatment process including a denitrification process through a flow adjusting tank.

In this case, a separate purification treatment facility may be additionally installed between the biological treatment process including the denitrification process and the discharge tank to further increase the degree of purification treatment.

As described above, the present invention can treat the food waste and livestock wastewater, which have been previously treated through separate treatment facilities at the same time using a single facility, thereby reducing the treatment cost.

In other words, the disposal of food waste by incineration requires enormous incineration facility installation and operation costs, and there is a problem of dioxin emission and air pollution due to incineration. There was a problem of leachate generation, and when the food waste is composted directly, there is a problem that the salt accumulates in the soil and acts as a high cause of crops, but the above problems are excluded by the method of the present invention.

In particular, the present invention can be expected to replace the import effect on the feed that is mostly dependent on the import through the food waste of the food waste, and the feed obtained by the method of the present invention contains a small amount of salt, so it is mixed with the feed compound Therefore, when fed to livestock there is an advantage that does not need to add salt to the feed compounded separately.

In addition, the present invention can promote the decomposition for composting by the complementary action of the characteristics of each of the food waste and livestock waste water can produce a good compost, without the need for a separate chemical physical and biological treatment Composting is done through the bay, so there is an advantage in reducing the incidental cost of processing.

In addition, the present invention by treating the livestock manure by using a sawdust fermentation purification facility to efficiently treat the manure and urine in the livestock manure containing a large amount of organic solid material without separating the existing facility costs for separation of manure, urine It is economical because the amount of moisture control material (sawdust, etc.), which has been a obstacle to composting due to supply and demand, is reduced by more than 90%, especially in the composting and purification treatments held by slurry pigs. The problem can be solved.

In the conventional high concentration livestock wastewater treatment, a large amount of energy and chemicals are added to biologically treat the wastewater separated from the solid-liquid, while the solid-liquid separation contaminants and sludge generated in the process have to be separately composted. In the treatment of manure manure using the sawdust fermentation purification system of the present invention, fermentation and purification are carried out simultaneously without adding any chemicals, so that the filtrate that has been brought down to the lower purification facility in parallel with the composting of organic solids in the upper fermentation tank is considerably made. It is possible to reduce the contamination load in the biological treatment process.

In the present invention, the fermentation over 6 months to the lignin in the sawdust is decomposed to obtain a good compost, the air used in the contact medium layer of the lower part of the fermenter is reused in the fermentation layer, in particular cold air contact Since it reaches the fermentation layer through the filter media layer can be expected to preheat the action to prevent the degradation of the fermentation efficiency due to temperature decrease.

In addition, in the present invention, it is possible to solve the caloric shortage problem of the fermenter by using food waste, which is one of the problems pointed out when treating livestock waste water alone, and also solve the problem of lack of external carbon source generated during purification treatment. By supplying a carbon source by using there is an advantage that can maintain an appropriate C / N ratio.

Claims (4)

A method of simultaneously treating food waste and livestock waste water, the method comprising the steps of screening and washing food waste to remove salt, crushing food waste in a salt-free state, and slurrying the slurry, and food waste in the slurry state. Mixing in the sump with the livestock manure, and a contact filter tank is provided at the lower part of the porous bottom surface, and the sawdust is filled at the bottom surface, and air is supplied from the outside via the contact filter tank and the porous bottom surface. Periodically spraying the mixed wastewater of the food waste and livestock waste stored in the sump into the sawdust upper surface of the sawdust fermentation septic tank, supplying air while stirring the mixture of the sprayed food waste and the livestock wastewater and sawdust Composting step by step, three of the food waste Homogenizing the concentration of the wastewater by storing the leaching filtrate from the contact filter medium of the washing water and the sawdust fermentation septic tank generated in the process, and removing the scum caused by injuring foreign matter in the homogenized wastewater from the pressure flotation tank. And a step of treating denitrification and residual pollutants through biological treatment of the wastewater that has undergone pressurization treatment. According to claim 1, Food waste that can be fed in the food waste from which the salt and spicy taste is removed in the step of sorting and washing the food waste is increased by heating at a high temperature in a dry feed method and then dried and pulverized to feed or wet feed method It is crushed in the state of water and treated with warming, sterilization or organic acid to kill decayed bacteria, and then mixed and fermented with mixed feed or agricultural by-products, and then fermented.The food wastes that are difficult to feed are comminuted and mixed with livestock wastewater to compost. Mixing treatment method of food waste and livestock waste water, characterized in that. According to claim 1, wherein the sawdust fermentation septic tank is supplemented by food waste having a carbon source rich in caloric insufficiency of the fermentation tank appearing in the treatment of livestock wastewater to maintain the appropriate C / N ratio to activate the fermentation, The air is supplied to the fermentation tank to decompose odorous substances by microorganisms to prevent odor generated during food waste treatment, characterized in that the mixed treatment method of food waste and livestock waste water. The method of claim 1, wherein the purification treatment for the leaching filtrate from the sawdust fermentation septic tank is a biological containing a high-efficiency denitrification process without supplying a separate external carbon source by supplementing the shortage of external carbon source with organic matter in the food waste washing water Mixed treatment method of food waste and livestock waste, characterized in that the treatment is made.