KR19990007630A - Food sink treatment device with kitchen sink by anaerobic digestion - Google Patents

Abstract

The present invention relates to a method of treating food waste generated at home by anaerobic digestion without separately collecting it, and to operating the food waste generated in the kitchen by attaching the apparatus to an existing sink drain to clean and quickly clean the food waste. Invented to reduce weight.

Food waste contains 85-90% water, and when incinerated, the calorific value of the incinerator is lowered due to the moisture contained in the incineration, which requires supplementary fuels such as light oil for complete incineration. It is a time when proper management is urgently needed such as suppressing food waste generation itself by increasing the amount of leachate generated by the holding water.

The general characteristics of food waste are 85-90% water content, 90% organic matter (VS), and 90% biodegradability. The organic components are 12.75% fat, 20.2% protein and 76% fiber. Therefore, these wastes can be fermented and extinguished by anaerobic digestion, even with the results of previous studies and sludge treatment in sewage treatment plants.

The present invention is to focus on this point to reduce the amount of food waste by anaerobic bacteria quickly and cleanly.

The present invention applies a method of reducing organic matters in the components of Sludge based on anaerobic digestion in sewage treatment equipment. Food waste is added to the inlet-crushing (dehydration)-hydrolysis (secondary dehydration)-acid production-acetic acid formation. -Gas formation (dehydration) such as methane-Drying and ripening process.

Odor is generated due to gas such as acid and methane generated during this process. To prevent the diffusion of the odor gas into the kitchen, a trap is installed at a drain hole installed at the bottom of the crushing device to prevent the generation of odor.

The configuration of the device is configured as follows and the operation of each component is as described in the specification.

1) inlet, 2) crusher (including driving motor), 3) acid generating chamber (hydrolysis chamber), 4) methane forming chamber (including acetic acid formation), 5) drying and ripening chamber, 6) gas drawing tube, 7) surplus consignee Exit, 8) Drain, 9) Trap 10) Drive motor (with timer), 11) Electric heater (with temperature controller), 12) Surplus outlet

In the present invention, the housewives of each household for food waste treatment are separated and then transported to a central processing unit, or collected and transported separately by US sources. There are many unpleasant things in terms of hygiene due to the tearing of the collection bags by the present invention, but the food waste generated by the present invention can be processed directly in the kitchen sink, which is the place where it is generated. It can be expected to greatly improve.

Description

Food sink treatment device with kitchen sink by anaerobic digestion

The present invention relates to a method of treating food waste generated at home by anaerobic digestion without separately collecting it, and more particularly, food waste generated by attaching and operating the food waste generated in the kitchen to an existing sink drain. Invented to reduce the weight of clean and quick.

Although Korea has been pursuing the appropriate treatment and reduction policy of various wastes, the amount of waste discharged per person per day exceeds 1Kg, and many policies have been established for proper management. Among these, food waste still accounts for about 30% of the total emissions. Therefore, the amount of food waste generated is 4,930 tons / day in Seoul and 15,075 tons / day nationwide. I'm doing it.

Food waste contains 85-90% water, and when incinerated, the calorific value of the incinerator is lowered due to the moisture contained in the incineration, which requires supplementary fuels such as light oil for complete incineration. It is a time when proper management is urgently needed, such as the amount of leachate generated by retained water increases and the food waste generation itself is suppressed.

The general characteristics of food waste are 85-90% of water content, 90% of organic matter (VS), and 90% of biodegradability. The decomposition rate is fast (P28 <Table 3-3> Comparison of characteristics of food waste and sewage) . In addition, in Examples 2 to 5 of the invention patent No. 136987 (Patent Name; Process for Treating Food Waste by Catalytic Pyrolysis. Date of Registration; 1998.2.2) After filtration under reduced pressure using a LASER, a raw material with 80% water content was used, and the volatile substance content was 98.9%, and the components were 12.75% fat, 20.2% protein, and 76% fiber content. Therefore, these wastes can be fermented and extinguished by anaerobic digestion, even with the results of previous studies and sludge treatment in sewage treatment plants.

The present invention is to focus on this point to reduce the amount of food waste by anaerobic bacteria quickly and cleanly.

1. Technical Field; Environment

2. Prior art in the field

As a method of treating food waste that has been put to practical use until now, it is a method of collecting and using it as a feed, landfilling, composting by aerobic fermentation, dumping after dehydration drying, and heating decay after dehydration drying. Since most food wastes are collected from the kitchen after being collected from the kitchen, they are cumbersome and have a lot of water in the process of handling, and there are a lot of inconveniences when handling them. It was a lot of adverse effects.

The technical problem to be achieved by the present invention is to reduce the food waste generated from the kitchen quickly and hygienically to prevent odors during treatment and to reduce the environmental hazard when the final processed product is reduced to the natural environment.

FIG. 1; Process diagram schematically showing the process of digesting food waste by anaerobic according to the method of the present invention.

2nd degree; Main section

Explanation of symbols for main parts of the drawings

1-inlet, 2-crusher (including driving motor), 3-acid generating chamber (hydrolysis chamber),

4-methane forming chamber (including acetic acid formation), 5-drying and aging chamber,

6-gas outlet pipe, 7-excess water outlet pipe, 8-drain pipe, 9-trap,

10-drive motor with timer, 11-electric heater with thermostat,

12-surplus outlet,

3; Detail view of trap to block odor

4; Detailed diagram of dehydration device after hydrolysis and digestion

The present invention applies a method of reducing organic matters in the components of the waste in the sewage treatment plant based on anaerobic digestion. The anaerobic digestion method for the treatment of sewage treatment plant sludge is added to the apparatus-hydrolysis-acid production-acetic acid formation. -After the process of methane formation, it is processed by repetition of withdrawing surplus waste.

The present invention is to apply the food waste to the inlet-crushing (dehydration)-hydrolysis (secondary dehydration)-acid production-acetic acid formation-gas formation (dehydration), such as methane-drying and aging process have.

Odor is generated due to gas such as acid and methane generated during this process. In order to prevent diffusion of the odor gas into the kitchen, a trap is installed at a drain hole installed at the bottom of the crushing device to prevent the generation of odor.

1. Composition of this unit

The configuration of this apparatus is as follows.

1) inlet, 2) crusher (including driving motor), 3) acid generating chamber (hydrolysis chamber), 4) methane forming chamber (including acetic acid formation), 5) drying and ripening chamber, 6) gas extraction pipe, 7) surplus water Exit, 8) Drain, 9) Trap, 10) Drive motor (with timer), 11) Electric heater (with temperature controller), 12) Surplus outlet

2. Function of the device

Looking at the principle of anaerobic digestion that is generally applied to help understand the operation of the device of the present invention.

2.1 Principle of Anaerobic Digestion (this text is partly quoted by Wastewater Treatment, Kim Dong-min, Cheongmun-gak, 1998 edition, P342-345)

Anaerobic digestion is a process in which high concentrations of organic solids and organic polymers are converted into more stable low-molecular substances such as gases, liquids, and inorganic substances by anaerobic conditions. Carbohydrates, fats and proteins are three substances. Among them, carbohydrates are mainly in the form of polymers such as fiber, semi-fiber, and starch. However, these polymers must be dissolved in water and broken down into low molecules before they can be finally metabolized by cells. Therefore, the preliminary step of anaerobic digestion for such substrates is hydrolysis, which is hydrolyzed by in vitro enzymes by various kinds of bacteria and broken down into glucose, fatty acids and amino acids, respectively, in the low molecular form. The small molecule thus decomposed is taken up by the cells of the microorganism and then catalyzed and assimilated. The anaerobic reaction is carried out step by step in productivity, acetic acid formation, methane formation.

(1) acid formation stage

The acid formation step refers to the process from the hydrolysis of the substrate to the production of carbon dioxide, hydrogen, and various carboxylic acids by the cells. The catabolism of the acid formation step takes the following steps.

Substrate ---------- → CO ₂ + H ₂ + Acetic Acid (1)

Substrate ---------- → Propionic Acid + Butyric Acid + Ethanol (2)

The first reaction occurs thermodynamically when the hydrogen partial pressure in the system is low enough, meaning that the free energy change ΔG is negative. When the partial pressure of hydrogen in the system is high, the second path is followed, resulting in the production of organic acids such as propionic acid and butyric acid and reducing substances such as ethanol.

(2) acetic acid formation step

In the acetic acid formation step, the produced organic acids such as propionic acid and butyric acid and ethanol are metabolized as follows.

_{CH 3 CH 2 COOH + 3H 2} O ---------- → CH 3 COOH + HCO 3 - + H + + 3H 2

Propionic acid acetic acid

CH ₃ CH ₂ CH ₂ COOH + 2H ₂ O ---------- → CH ₃ COOH + 2H ₂

Butyric Acid Acetic Acid

CH ₃ CH ₂ OH + H ₂ O ---------- → CH ₃ COOH + 2H ₂

For the acetic acid formation reaction to proceed without supplying energy from the outside, the change in free energy value must be ΔG negative. However, if the generated hydrogen gas is quickly removed without accumulating in the cyste and the partial pressure is kept low, the ΔG value becomes negative. It is methane producing bacteria and sulfate reducing bacteria that play such a role. As shown below, the metabolic activity of acetic acid-producing bacteria is dependent on methane-forming bacteria.

4H ₂ + CO ₂ ------ → ΔCH ₄ + 2H ₂ O

(3) methane formation

Methane-producing bacteria are classified into four types: Methanobacterium, Methanococcus, Methanosarcina, and Methanospillium. Substrates that can be used directly by these bacteria are acetic acid, hydrogen, carbon dioxide, formic acid, methanol, and the like, and fatty acids and alcohols are transferred to methane and carbon dioxide under the premise of non-methane bacteria and methane bacteria. Such non-methane bacteria are some acetogenic bacteria. According to Jeris and McCarty, the most abundant intermediate in the anaerobic fermentation of carbohydrates, lipids and proteins is acetic acid and about 70% of the final release of methane is converted from it.

^{_{CH 3 COO - + H 2 O}} -------- → CH 4 + HCO 3 - + energy

The bicarbonate is converted to carbon dioxide again, the rate depends on the pH.

The above equation is the first pathway of methane production and the second pathway is methane formation by carbon dioxide or bicarbonate and hydrogen. The second pathway is important enough to influence the entire anaerobic reaction. Because this reaction removes hydrogen in the system and keeps its partial pressure low, it is possible to produce acetic acid.

Since methane producing bacteria have a low growth rate, it is important to maintain optimal environmental conditions such as temperature and pH, and hydrogen partial pressure has a significant effect on the overall fermentation reaction rate in the system, but its concentration is very low and thus difficult to monitor. Instead, if the hydrogen partial pressure becomes too high, pH can be seen in the system as non-acetic acid such as propionic acid.

2.2 Actions of constituent devices

The operation of each component device is as follows.

1) inlet; The inlet is installed at the bottom of the sink bowl, and food waste and drainage are put together, and some of the surface water existing in the drainage and food waste is drawn out to the sewer by a screen (grating net) installed at the bottom. Also make sure that the water is separated out.

2) shredders (including drive motors); The food waste collected from the inlet is crushed into small particles (less than 3 mm) to make it easier for the next process. In this process, the surface water attached to the surface of the waste is separated by sewage through some sort of drainage pipe (35-45% of water is dehydrated).

3) acid production chamber (hydrolysis chamber); Waste that passes through the crusher is introduced into the acid production. The temperature here is maintained at around 35 ° C and is automatically maintained by an electric heater. It is also the place where severe odors occur because waste is hydrolyzed and acid is generated. Here, the waste stays for 12-24 hours and the waste is converted into organic acids and large amounts of water, such as propionic acid and butyric acid. The structure here is screw convex and the part going to the next stage is cone, so that part of the generated water is dehydrated (15-18% of water is dehydrated). The upper part is attached with a gas outlet pipe to take out the odor and gas generated. In addition, the bottom portion of the cone (cone) is attached to the excess water withdrawal pipe for drawing the dehydrated surplus water.

4) methane forming chambers (including acetic acid formation); Waste that passes through the acid production chamber is transferred to the methane formation chamber. The temperature here is controlled by an electric heater to maintain a temperature of 55 ° C, which is suitable for high temperature fire extinguishing. Here, organic acids such as propionic acid and butyric acid produced in the acid generating chamber are metabolized into acetic acid by moisture. This metabolized acetic acid is methanated by methanogenic bacteria. Here, the waste is extinguished for 5-7 days, which causes the food waste to be gasified and extinguished. The structure is screw convex, just like the acid generating chamber, and the part that goes to the next stage is cone, so that part of the generated water is dehydrated (3-6% of water is the result of experiment). The upper part is attached with a gas outlet pipe to remove odor and generated gas. In addition, the bottom portion of the cone (cone) is attached to the excess water withdrawal pipe for drawing the dehydrated surplus water.

5) drying and ripening room; Wastes that pass through the methane chamber are lost about 70-90%, but some of the less easily decomposed vegetable plots such as ligrin and minerals remain with water. The undigested minerals and organics are transferred to the drying and aging chamber. The drying and aging chamber is located inside the acid generating chamber and the methane forming chamber, and consists of a screw conveyor to be dried and aged during the transfer process.

6) gas drawing pipe; It is a pipe for drawing out various gases generated from the acid generating chamber and the methane forming chamber, and is installed at the upper part of each chamber, and the extracted gas is led to the lower end of the trap.

7) surplus water withdrawal pipe; It is installed in the lower part of each chamber to withdraw the dewatered excess water from the cone of the acid generating chamber and the methane formation chamber, and the surplus water extracted therefrom is led to the lower end of the trap.

8) drain pipe; It is a pipe for withdrawing the drained water drawn from the inlet, the crusher and the excess water withdrawal pipe and the gas withdrawn into the gas withdrawal pipe.

9) traps; P-type or S-type traps are used at the bottom of the crusher to prevent backflow of odor from the sewer and odor from gas and excess water.

10) driven motors (including timers); As a motor for driving the screw conveyor for transporting and mixing the wastes of the acid generating chamber, the methane forming chamber and the drying and aging chamber, the speed is properly controlled by a timer.

11) electric heaters (including thermostats); The temperature is controlled by a thermostat as a heater for proper temperature maintenance to promote the reaction conditions of the acid generating chamber and the methane forming chamber.

12) surplus outlet; Finally, the dried and aged waste is withdrawn and installed at the bottom of the aging chamber.

Example

The results of the experiment using food waste generated in my house are as follows.

300g collected in the state discharged in the usual state, and crushed by the juicer to separate the water and the device manufactured for the experiment (experimental device is made of 80mm internal diameter acrylic tubing with screw conveyors with pitch 30mm inside) After the temperature was controlled by electric heater, the outside was insulated, and the upper part of the acid generating chamber and the methane forming chamber were equipped with a gas outlet for drawing gas, and a lower outlet for drawing out the moisture generated at the bottom. According to the experimental results, the driving was performed by controlling the formation speed of the small girder motor and the reduction belt of 25W).

As shown in the table, when crushed by green juice, water of 90-120g is generated, which indicates that about 30-40% of the total amount of water is removed. Next, about a day after the hydrolysis began, gas was generated with a bad smell and a large amount of water began to be produced. It was maintained at 35 ℃ by electric heater and the feed speed was rotated about 1 hour per day at about 1 / 10th of rpm. The next step, the methane fermentation chamber, was dehydrated by the cone form just before the transfer, and about 45-55 g of water was dehydrated. It can be seen that about 15-18% of the total input is dehydrated. Next, the food waste transferred to the methane formation chamber continued to form water and fermentation began. Gas was generated by the generation of a bad smell like a relatively rotting egg. It was maintained at 55 ℃ by electric heater, and the feed speed was rotated about 1 hour per day at about 1 / 10th of rpm. Dehydration was achieved by the cone shape just before the maturation and drying chamber transfer, and about 10-20g of water was dehydrated. It can be seen that about 3-6% of the total input is dehydrated. Next, the amount of surplus discharged through the drying and aging chambers averaged about 45g, leaving only 15% of the original input.

In the present invention, the housewives of each household for food waste treatment are separated and then transported to a central processing unit, or collected and transported separately by US sources. There are many unpleasant things in terms of hygiene, such as tearing of the collected bags, but the food waste generated by the present invention can be processed directly in the kitchen sink, which is the place where it is generated. It can be expected to improve.

Claims (3)

Treatment device that treats food waste by anaerobic processor attached to kitchen sink The apparatus of claim 1, wherein the food waste is transferred and screwed by a screw. The trap apparatus according to claim 1, for preventing odors from gas and wastewater generated from an acid generating chamber and a methane forming chamber.