CN206089691U - Organic garbage resource recycling system - Google Patents

Abstract

The utility model relates to an organic garbage recycling system, which comprises a pretreatment unit, an organic matter decomposition unit and a methane production unit which are connected in sequence; a pretreatment unit: an automatic classification organic garbage screening machine and an ultrasonic pretreatment machine; and (3) decomposing organic matter units: a reactor for decomposing organic matters and a physical precipitation tank; a methanogenic unit: a pH adjusting cylinder, a methane-producing bioreactor and a sludge settling cylinder; the outlet of the screening machine is connected with the inlet of the pretreatment machine, the outlet of the pretreatment machine is connected with the inlet of the reactor for decomposing organic matters, the outlet of the reactor for decomposing organic matters is connected with the inlet of the nutrient solution of the precipitation cylinder, the outlet of the nutrient solution is connected with the inlet of the adjusting cylinder, and the outlet of the adjusting cylinder is connected with the inlet of the methane-producing bioreactor; the outlet of the reactor is connected with the water inlet of the sludge sedimentation tank. The system has the advantages of small occupied area, low energy consumption, simple operation, low operation cost, less odor generation, capability of effectively recycling all organic matter resources in the garbage, no sewage discharge, no environmental pollution and the like.

Description

Organic Waste Recycling System

This case claims the priority of the U.S. application No. 62/311,916 filed on March 23, 2016, and the title of the invention is: An Innovative 2-Stage Food Waste Recycling System (An Innovative 2-Stage Food Waste Recycling System), and the content recorded in it All incorporated herein.

technical field

The utility model relates to a waste recycling system, in particular to an organic waste recycling system.

Background technique

In recent years, with the accelerated development of urbanization in China, the amount of garbage generated in cities every day is increasing rapidly. How to properly deal with urban domestic garbage and how to utilize it as a resource has become a hot topic. According to statistics, about 40% of the vast majority of urban waste in the world is kitchen waste. The main feature of this type of waste is that it is rich in organic matter such as crude protein and crude fiber, so it is perishable and produces stench. On the other hand, due to the high water content and low calorific value of this type of waste, it generally cannot be directly incinerated. At present, due to the lack of comprehensive treatment equipment and systems, municipal waste has caused a series of serious environmental problems, including water, soil and air pollution. Therefore, the harmless, resourceful and reduction treatment of this kind of garbage has attracted more and more attention from all walks of life.

Traditionally, the anaerobic digestion process can effectively convert the organic matter in the garbage into biogas for utilization. Governments of various countries have also planned to invest or build many large-scale centralized anaerobic digestion systems to deal with organic waste generated in cities. However, this traditional centralized organic waste treatment system has many limitations. For example, the treatment system occupies a large area, requires a complex waste logistics transportation system, and needs to be equipped with a complex waste sorting system. On the other hand, there are two main types of final products from this type of centralized anaerobic digestion system: biogas and biogas residue. Among them, the generated biogas is generally used for power generation, because complex equipment is required to convert the heat energy of the biogas into electricity, and its energy efficiency is very low. On the other hand, the generated biogas residue contains refractory or non-degradable impurities, so its nutritional value is low, the effect of composting is poor, and the market income is low. Therefore, generally speaking, the economic returns of large-scale centralized anaerobic digestion systems are not high, and the government needs to invest a lot of manpower and material resources to build and maintain them. In addition, for cities with high land value, it is difficult to find a suitable site to build a large-scale centralized organic waste treatment system. Therefore, how to build (especially in densely populated cities) an efficient organic waste treatment system has become a difficult point in solving this type of waste treatment process.

Utility model content

The main purpose of the utility model is to provide a new method for resource recycling of organic waste, so as to turn all the organic waste in the garbage into products with market value and realize the complete resource utilization of the organic waste.

Another object of the present invention is to provide a system applicable to the above method.

For this reason, on the one hand, the utility model provides a kind of organic waste recycling method, and described method comprises the following stages successively:

(1) Pretreatment stage: the organic matter in the garbage is partially ground and separated from other non-organic matter, and the ground organic matter is turned into a slurry, and the slurry is subjected to ultrasonic pretreatment;

(2) Decomposing organic matter stage: using a decomposing organic matter reactor to decompose the slurry obtained in step (1) after ultrasonic pretreatment through microbial decomposition into a decomposition product composed of waste oil, nutrient solution and solid residue;

(3) Methanogenic stage: use a methanogenic bioreactor to convert the nutrient solution obtained in step (2) into methane-containing biogas through anaerobic activated sludge fermentation; The treated water is reused in the pretreatment stage for slurry formation.

The method described in the utility model adopts the stage of pretreatment, the stage of decomposing organic matter and the stage of producing methane to turn all the organic matter in the garbage into three kinds of products with market value, so as to realize the complete resource utilization of organic waste. The three types are waste oil, nutrient solution (rich in organic acids) and solid residue (rich in protein), wherein the waste oil can be finally converted into biodiesel; the nutrient solution can be finally converted into biogas; solid After further drying, the residue can be finally converted into environmentally friendly feed, such as fish feed. In addition, the water generated in the conversion process can be treated and reused in the pretreatment stage to form slurry through the membrane filter, and the method of the utility model can make the whole method discharge no sewage through the cooperation of three stages.

The waste oil, nutrient solution and solid residue described in the utility model are defined according to the density of the components in the obtained decomposed product. After a certain period of physical precipitation, the obtained decomposed product will be clearly stratified, and the uppermost layer is the waste product with the lowest density. Grease; the bottom layer is solid residue (solid precipitation, total solid content (TS) is about 10% to 15%), the solid residue is mostly food residue after microbial decomposition, because after hydrolysis, fermentation and acidification, the residue is Based on macromolecular protein, the content of protein is about 30-40% according to the measurement; the middle layer is a nutrient solution rich in organic acids (the suspended solid particle content (SS) in the nutrient solution can be less than 5,000mg /L), the liquid contains a large amount of organic acids, which are the food of methanogenic bacteria, and the methanogenic bacteria will convert the organic acids in this type of water into methane.

According to a specific embodiment of the utility model, in the pretreatment stage:

Using an automatic sorting organic waste screening machine to process the waste so that the organic matter in the waste is partially ground and separated from other non-organic matter, and the ground organic matter is turned into a slurry;

The automatic sorting organic waste screening machine includes a grinding and separating device, and the grinding and separating device includes:

A cylinder, the upper part of which is provided with a feed port for the garbage to be thrown in, and the lower part of the cylinder is provided with a discharge hole;

A stirring device, which can be rotatably installed in the cylinder, and can grind the organic waste in the waste into organic particles by rotating and stirring;

The spraying device faces into the cylinder and can spray liquid towards the discharge hole, and the liquid carries the organic particles out of the cylinder through the discharge hole;

Put the garbage and cellulose-containing filler into the automatic sorting organic garbage screening machine, and grind the organic matter in the garbage by stirring the paddle clockwise and counterclockwise, and sprinkle water to form the ground organic matter. the slurry.

Preferably, the organic matter in the garbage is ground to a diameter of less than 2mm.

Preferably, the cellulose-containing filler includes one or more of rice husk, sawdust, and straw.

Preferably, the solid content of the slurry is 5%-10%.

The use of automatic sorting organic waste screening machine can realize automatic classification without complicated waste sorting system, which saves floor space and labor costs. The working principle of the automatic sorting organic garbage screening machine described in the utility model is to mix the garbage with some cellulose-rich fillers, such as chaff, sawdust, and straw fillers, and then pass the stirring paddles in the cylinder of the machine clockwise. and counterclockwise agitation to grind the organic matter in the garbage, preferably until the particle diameter is less than 2 mm; then sprinkle water into the cylinder through the spraying device installed in the cylinder, so that the ground fine particle organic matter is mixed with water Flush out; these added spray water can come from the nutrient solution rich in organic acids produced in the subsequent decomposition of organic matter reaction stage or the product water in the subsequent methanogenic stage (such as the product water in the membrane filter): through the machine After treatment, the organic matter in the garbage will become a homogeneous slurry and flow out to the next unit. The solid content of the slurry is preferably 5-10%, while the large pieces of refractory or non-degradable garbage such as animal bones, wooden chopsticks, disposable Substances such as non-toxic plastic tableware will continue to remain in the cylinder of the machine.

The automatic sorting organic waste screening machine described in this utility model is the automatic sorting organic waste in the application date of July 1, 2016, the application number submitted to the Chinese Patent Office is 201610514680.8, and the invention name is "an automatic sorting organic waste processing system". processing system. This case incorporates all the contents recorded in this case by reference.

According to a specific embodiment of the utility model, in the pretreatment stage:

Ultrasonic pretreatment is performed on the slurry with an ultrasonic pretreatment machine, the frequency of ultrasonic pretreatment is 20-60KHZ, and the hydraulic retention time is 5-30 minutes.

Ultrasonic waves will cause cavitation, which can destroy the cell wall or cell membrane of the organic matter, so that the material components in the cells can be released better, increase the solubility of the organic matter in the slurry, and help shorten the microbial life in the next stage of decomposing organic matter. Reaction time.

According to a specific embodiment of the present utility model, in the stage of decomposing organic matter:

Control the pH of the decomposition system to be 3.5 to 6.5, the temperature to be 28 to 40°C and the hydraulic retention time to be 2 to 5 days; and

The waste oil, the nutrient solution and the solid residue are separated from the decomposed mixture by standing in a physical settling tank.

Preferably, the decomposition organic matter reactor is also provided with a mechanical stirring device, a pH meter and/or a temperature control device.

Controlling the pH and temperature within this range is beneficial to the hydrolysis, fermentation and acidification of microorganisms. The hydraulic retention time of the slurry obtained in the pretreatment stage in the reactor for decomposing organic matter only needs 2 to 5 days to complete the decomposition and conversion reaction. to the next unit.

As mentioned above, the slurry obtained in step (1) (slurry rich in organic matter) is decomposed by microorganisms and converted into three products: waste oil, nutrient solution rich in organic acids and solid residue rich in protein. Since the densities of these three products are different, obvious stratification may occur after a certain period of physical precipitation. The uppermost layer is the waste oil with the lowest density, which can be recycled as raw material for biodiesel production; the bottom layer is the solid residue rich in protein (total solid content (TS) is about 10-15%). The quasi-solid residue can be further dried to become the raw material of environmentally friendly feed; the middle layer is a nutrient solution rich in organic acids (the suspended solid particle content (SS) in the nutrient solution is less than 5,000mg/L).

According to a specific embodiment of the present invention, in the stage of decomposing organic matter, after the steady-state operation of the organic matter decomposition reactor, the effective microbial strains in the reactor include hydrolyzing bacteria, fermenting bacteria and acid producing bacteria. According to the relative abundance of bacteria, effective microbial strains accounted for 75% to 95%.

Preferably, based on the relative abundance of total bacteria, the effective microbial strains include 1-5% hydrolytic bacteria, 60-85% fermentative bacteria and 6-20% acid-producing bacteria.

The proportion of effective microbial strains and the proportion of various bacteria can be sequenced by gene sequencing method (preferably 16S rRNA GeneSequencing).

The use of the above-mentioned microorganisms has the advantages of high decomposition reaction efficiency, fast processing of organic matter, and the like.

Exemplary hydrolytic bacteria applicable to the present invention include, but are not limited to, Clostridium and/or Prevotella hydrolytic bacteria.

Exemplary fermenting bacteria applicable to the present invention include but not limited to one or more fermenting bacteria of the genus Lactobacillus, Lactococcus and Leuconostoc.

The acid-producing bacteria described in the present invention include acetogenic bacteria and acidifying bacteria; exemplary acetogenic bacteria applicable to the present invention include but not limited to acetogenic bacteria of the genus Acetobacter. Exemplary acidifying bacteria that may be used in the present invention include, but are not limited to, acidifying bacteria of the genus Megasphaera.

According to a specific embodiment of the present utility model, in the methanogenic stage, the methanogenic bioreactor is an upflow anaerobic sludge bed reactor, and

Adjusting the pH of the nutrient solution or the nutrient solution separated from the physical settling tank to 6-7 and allowing it to enter the upflow anaerobic sludge bed reactor;

Control the temperature in the reactor to 28-40°C and the hydraulic retention time to be 7-10 days;

Preferably, the hydraulic retention time of the permeable membrane filter is also controlled to be 1-2 days.

If the nutrient solution produced in the stage of decomposing organic matter described in the present invention is calculated by soluble chemical oxygen demand (SCOD), its range is usually 20,000-100,000 mg/L. After treatment in the methanogenic stage, it can be reduced to 4,000-15,000mg/L. If it is further treated with a membrane filter, it can be further reduced to 1,000-8,000 mg/L.

Considering the compactness of the whole recycling system, the utility model preferably adopts an upflow anaerobic sludge bed (UASB) reactor. Nutrient solution rich in organic acids can enter from the bottom of the reactor, while the biogas produced can be collected at the top of the reactor. On the other hand, in order to prevent a large amount of anaerobic sludge with methanogenic bacteria from being lost, a small settling tank can also be equipped at the back end of the UASB reactor, and the anaerobic sludge in the settling tank can be regularly drained according to the system operating conditions. The sludge is pumped back into the reactor.

Controlling the temperature in the methanogenic bioreactor within the range of 28°C to 40°C can make the growth environment in the reactor most suitable for the growth of methanogenic bacteria. Most of the organic matter in the nutrient solution rich in organic acids is converted into biogas rich in methane within 7-10 days of hydraulic retention time, and the content of methane is about 50%-85%. The gas can further increase the methane content after passing through gas purification devices such as water vapor separation and sulfur removal. The content of organic matter contained in the effluent water after the unit reaction is usually in the range of 4,000-15,000 mg/L in terms of soluble chemical oxygen demand (SCOD).

According to a specific embodiment of the present invention, in the methanogenic stage, after the steady-state operation of the methanogenic bioreactor, the effective microbial strains in the reactor include methanogenic bacteria and acetogenic bacteria. According to the abundance meter, effective microbial strains account for 20-35%.

The method described in the utility model is preferably applicable to kitchen waste. These food waste can come from local communities, food processing factories and catering factories.

On the other hand, the utility model has developed a resource recycling system of organic waste, which can be applied to the method of the utility model. Specifically, the system includes a pretreatment unit, a decomposition organic matter unit and a methane production unit connected in sequence:

The pretreatment unit includes: an automatic classification organic waste screening machine and an ultrasonic pretreatment machine;

The automatic sorting organic waste screening machine includes a grinding and separating device, and the grinding and separating device includes:

A cylinder, the upper part of which is provided with a feed port for the garbage to be thrown in, and the lower part of the cylinder is provided with a discharge hole;

A stirring device can be rotatably installed in the cylinder, and can grind the organic waste in the waste into organic particles by rotating and stirring;

The spraying device faces into the cylinder and can spray liquid towards the discharge hole, and the liquid carries the organic particles out of the cylinder through the discharge hole;

The decomposed organic matter unit includes a decomposed organic matter reactor and a physical settling tank;

The methanogenic unit includes: a pH adjustment tank, a methanogenic bioreactor and a sludge settling tank;

The material outlet of the automatic classification organic waste screening machine is connected with the material inlet of the ultrasonic pretreatment machine, and the material outlet of the ultrasonic pretreatment machine is connected with the material inlet of the decomposed organic matter reactor; the material of the decomposed organic matter reactor The outlet is connected with the nutrient solution inlet of the physical sedimentation tank, the nutrient solution outlet of the physical sedimentation tank is connected with the material inlet of the pH adjustment tank, and the material outlet of the pH adjustment tank is connected with the methanogenic bioreactor. The material inlet is connected; the material outlet of the methanogenic bioreactor is connected with the water inlet of the sludge settling tank.

Preferably, the methanogenic unit further includes a membrane filter, and the water outlet of the sludge settling tank is connected to the water inlet of the membrane filter.

The automatic sorting organic garbage screening machine of the utility model is as mentioned above, which can grind the organic matter in the garbage and separate it from other non-organic matter, and make the ground organic matter into slurry.

The ultrasonic pretreatment machine described in the utility model can perform ultrasonic on the obtained slurry.

The reactor for decomposing organic matter described in the utility model is a place where microbial bacteria decompose the ultrasonicated slurry into decomposed products composed of waste oil, nutrient solution and solid residue.

The physical settling cylinder of the utility model can separate the waste oil, the nutrient solution and solid residue from the decomposed matter by standing still.

The pH adjustment tank of the utility model can be used as a place for adjusting the pH of the nutrient solution, and the pH can be adjusted to 6-7.

The methanogenic bioreactor of the utility model can use anaerobic activated sludge to convert the nutrient solution into biogas containing methane.

The permeable membrane filter of the utility model can process the water produced by the methanogenic bioreactor. Preferably, the permeable membrane filter includes an intermediate cylinder, a membrane module and a water production cylinder connected in sequence; the material inlet of the intermediate cylinder is connected with the water outlet of the sludge settling cylinder.

According to a specific embodiment of the present utility model, in the recovery system of the present utility model, the spray device in the automatic sorting organic waste screening machine is connected to the water outlet of the water production tank or the physical sedimentation tank. The nutrient solution outlet is connected.

According to a specific embodiment of the utility model, the recycling system of the utility model further includes a deodorizing device, which is connected to the water production tank and the ultrasonic pretreatment machine through pipelines respectively, and Install exhaust fans on the road.

According to a specific embodiment of the utility model, in the recovery system of the utility model, the decomposition organic matter reactor is further provided with a mechanical stirring device, a pH meter and/or a temperature control device.

According to a specific embodiment of the utility model, the system of the utility model further includes a sludge drying device, which is connected with the solid sediment outlet of the physical sedimentation tank.

According to a specific embodiment of the utility model, the system of the utility model further includes an automatic control device for automating the entire system.

According to actual needs, each unit, reactor, equipment, etc. of the system described in the present invention can be connected through pipelines or other methods, and valves or pumps can be arranged between pipelines.

The system described in the utility model has the advantages of small footprint, low system energy consumption, simple system operation, low operating cost, less odor generation, effective recycling of all organic resources in garbage, no sewage discharge, and no environmental pollution. .

The method and the system provided by the utility model are especially suitable for the recycling and utilization of kitchen waste. The system can continuously separate the organic matter in the garbage from other refractory or non-degradable garbage, and then use microorganisms to turn all of them into products with market value, realizing the complete resource utilization of organic waste.

The new organic waste resource recycling system provided by the utility model is used to separate the organic matter in the waste from other refractory or non-degradable waste, and realize the complete resource utilization of organic waste. The recycling system consists of three units: a pretreatment unit, a decomposition organic matter unit and a methane production unit.

As mentioned above, the new organic waste resource recycling system uses microorganisms to turn all the organic matter in the waste into three products with market value.

As mentioned above, the new organic waste recycling system, wherein the three products are:

Waste oils and fats, which can eventually be converted into biodiesel;

A nutrient solution rich in various organic acids, which can eventually be converted into biogas; and

A protein-rich solid residue that can eventually be converted into environmentally friendly feed.

As mentioned above, the new organic waste recycling system, wherein, the pretreatment unit may include:

Automatic sorting organic waste screening machine, which can grind the organic matter in the waste into fine particles, and transform it into a homogeneous slurry with a solid content of 5% to 10%;

Ultrasonic pretreatment machine, which can destroy the cell wall or cell membrane of organic matter, so that the material components in the cells can be released better, increase the solubility of organic matter in the slurry, and shorten the subsequent reaction time.

As mentioned above, the new organic waste recycling system, wherein the decomposed organic matter unit may include:

A reactor for decomposing organic matter, which can be equipped with a mechanical stirring device, so that the organic matter in the reactor can be mixed evenly with the microorganisms that can decompose organic matter, and the reactor can be equipped with a device that can automatically adjust the pH value and temperature to maintain the reaction The microbial bacteria in the reactor are in the most suitable environment for growth, and the hydraulic retention time of the reactor is 2 to 5 days;

Physical sedimentation tank, after passing through the physical sedimentation tank, the slurry is divided into three layers, waste oil, nutrient solution rich in various organic acids and solid residue rich in protein.

As mentioned above, the new organic waste recycling system, wherein, the methane production unit may include:

Methanogenic bioreactor, the reactor can be an upflow anaerobic sludge bed (UASB), and can be equipped with a settling tank at the rear end of the reactor, and the anaerobic sewage in the settling tank can be regularly removed according to the system operation The mud is pumped back into the reactor, which is equipped with a device that can automatically adjust the temperature to maintain the most suitable environment for the growth of effective bacteria in the reactor. The hydraulic retention time of the reactor is 7 to 10 days. Most of the organic matter in the nutrient solution will be converted into biogas rich in methane in the reactor;

Membrane filter, the hydraulic retention time design value of the membrane filter is 1 to 2 days, the membrane filter is used to treat the effluent of the methanogenic bioreactor, and keep useful microorganisms in the system as much as possible The water will not be lost, and further degrade the organic matter contained in the water.

As mentioned above, in the new organic waste recycling system, all the water produced by the permeable membrane filter can be reused in the organic waste screening machine in the pretreatment stage, so the whole system has no sewage discharge.

The system described in the utility model can recycle the municipal solid waste, especially the organic waste in the kitchen waste, and can separate the organic matter in the waste from other refractory or non-decomposable waste. In the anaerobic digestion process, the organic matter in the garbage can be completely recycled by using microorganisms. After being treated by this system, the degradable organic substances in the garbage will become three kinds of products with market value: waste oil (which can be finally converted into biodiesel), nutrient solution rich in various organic acids (which can be finally into biogas) and protein-rich solid residues (which can eventually be converted into environmentally friendly feed). The system has the advantages of small footprint, low system energy consumption, simple system operation, low operating cost, less odor, and can effectively recycle all organic resources in garbage, no sewage discharge, and no environmental pollution. Therefore, the system can be used as an organic resource recycling system for general municipal solid waste to recycle the degradable organic resources in the garbage.

As shown in Figure 1, the system described in the utility model mainly consists of 3 units: a pretreatment unit, a decomposition organic matter unit and a methane production unit. Correspondingly, the method using the system is divided into 3 stages, which are respectively: pretreatment stage, decomposition of organic matter stage and methanogenic stage. As shown in Figure 1, after the pretreatment unit, complex organic matter, such as starch, cellulose, protein, lipid, etc., will be separated from the garbage and enter the decomposing organic matter unit. In this unit, complex organic matter such as carbohydrates, proteins or fats in organic waste will be decomposed into soluble organic matter by microorganisms, and then these soluble organic matter will be changed into shorter carbon chains by microorganisms that can produce organic acids organic acids, ethanol, carbon dioxide and hydrogen, etc. After the decomposition reaction at this stage, the organic matter will be transformed into three products that can be recycled and utilized: waste oil, nutrient solution and solid residue. Among them, waste oil can be used as raw material for the production of biodiesel; the solid residue rich in protein can be dried to become the raw material for the manufacture of environmentally friendly feed (such as fish feed); the nutrient solution rich in soluble organic acids will enter the next production methane unit. In this methanogenic unit, methanogenic bacteria further convert the organic acids into biogas whose main components are methane and carbon dioxide.

The stage and unit that can be applied to the present utility model are further described in detail below:

(1) Preprocessing unit (for the preprocessing stage of the method)

As shown in Figure 2, the organic waste pretreatment unit may include an automatic sorting organic waste screening machine and an ultrasonic pretreatment machine. The main function of this unit is to continuously separate the organic matter in the garbage and grind it into a homogeneous slurry with small particles, so that the organic matter that can be recycled can enter the next unit for biochemical reaction; and through the action of ultrasonic waves, Accelerate the subsequent reaction efficiency. The detailed description of the organic waste screening machine and ultrasonic processor is as follows:

(a) Automatic sorting organic waste screening machine

The automatic sorting organic waste screening machine is as described above. The working principle of the screening machine is to first mix the garbage with some cellulose-rich fillers, such as chaff, wood chips, and straw fillers, and stir the garbage in the garbage by the clockwise and counterclockwise stirring of the stirring paddle in the machine cylinder. Partially grind the organic matter, preferably until the particle diameter is less than 2 mm; then sprinkle water into the cylinder body through the spray device installed in the cylinder body, so as to wash out the ground fine particle organic matter with water; these added spray water , which can come from the nutrient solution rich in organic acids produced by the subsequent decomposition of organic matter reaction unit or the water produced by the permeable membrane filter in the subsequent methanogenic unit; after being processed by this screening machine, the organic matter in the garbage will become homogeneous The slurry flows out to the next unit, and the solid content of the homogeneous slurry is preferably 5% to 10%, while large pieces of refractory or non-degradable garbage such as animal bones, wooden chopsticks, and disposable plastic tableware will continue to remain in the cylinder of the machine.

(b) Ultrasonic pretreatment machine:

The homogeneous slurry processed by the automatic sorting organic waste screening machine enters a low-frequency ultrasonic pretreatment machine, preferably, the frequency range of the ultrasonic wave is 20-60KHz. The ultrasonic wave will cause cavitation in the cylinder, which can destroy the cell wall or cell membrane of the organic part, so that the material components in the cells can be released better, and the solubility of the organic matter in the slurry can be increased, which is beneficial to shorten the next decomposition. Reaction time of microorganisms in organic matter unit.

(2) Decomposing organic matter unit (for the stage of decomposing organic matter with the method)

Most of the biochemical reactions are carried out in the decomposing organic matter unit. As shown in Figure 3, the unit may include a decomposition organics reactor and a physical settling tank. The complex organic matter in the pretreated homogeneous slurry will be decomposed into low molecular soluble organic matter in the reactor, and then further converted into organic acid. After being treated by this unit, the organic matter in the garbage is transformed into 3 products: waste oil, nutrient solution and solid residue. These 3 products will be separated after physical precipitation for a certain period of time. A detailed description of the reactor for decomposing organic matter and the physical settling tank is as follows:

(a) Reactor for decomposition of organic matter

Most of the hydrolysis, fermentation and acidification reactions are completed in this bioreactor. The bioreactor is equipped with a mechanical stirring device to increase the mass transfer rate of the biochemical reaction, so that the organic matter and microorganisms in the reactor can be fully mixed evenly, thereby increasing the speed of hydrolysis, acidification and fermentation. The reactor can be equipped with a device that can automatically adjust the pH value and temperature. The pH value in the reactor is maintained within the range of 3.5-6.5, and the temperature is maintained within the range of 28-40°C. Under normal conditions, the hydraulic retention of the reactor The time is 2 to 5 days, and it will flow to the next unit.

(b) Physical sedimentation tank

The slurry rich in organic matter is decomposed by microorganisms in the decomposition organic matter reactor into three products: waste oil, nutrient solution rich in soluble organic acids and solid residue rich in protein. Since the densities of these three products are different, obvious stratification may occur after a certain period of physical precipitation. The top layer is waste oil with the lowest density, which can be recycled as raw material for biodiesel production; the bottom layer is protein-rich solid residue (total solid content (TS) is about 10% to 15%), Such solid residues can be further dried to become raw materials for environmentally friendly feeds. During the reaction process, the solid residues can be returned to the reactor for decomposing organic matter to increase the effective bacteria content of the reactor for decomposing organic matter. When the system is running stably, the solid residue can no longer continue to return to mud; the middle layer is a nutrient solution rich in soluble organic acids (the suspended solid particle content (SS) in the nutrient solution is less than 5,000mg/L). As shown in Figure 3, there are two destinations for the nutrient solution: part of the nutrient solution can be returned to the organic waste screening machine in the previous pretreatment unit; part of the nutrient solution can enter the next methanogenic unit. The content of organic matter in the nutrient solution rich in soluble organic acids ranges from 20,000 to 100,000 mg/L in terms of soluble chemical oxygen demand (SCOD).

(3) Methanogenic unit (for the methanogenic stage of the method)

After the pH of the nutrient solution rich in organic acids is adjusted to 6-7, it will be converted into biogas rich in methane under the action of methanogenic bacteria. As shown in Figure 4, the methanogenic unit may include a methanogenic bioreactor and a membrane filter, and the detailed description of the methanogenic bioreactor and the membrane filter is as follows:

(a) Methanogenic bioreactor

Considering the compactness of the whole recycling system, the utility model can adopt an upflow anaerobic sludge bed (UASB) reactor. Nutrient solution rich in organic acids can enter from the bottom of the reactor, while the biogas produced can be collected at the top of the reactor. On the other hand, in order to prevent a large amount of anaerobic sludge with methanogenic bacteria from being lost, a small settling tank can be equipped at the back end of the UASB reactor, and the anaerobic sludge in the settling tank can be regularly drained according to the system operating conditions. The sludge is pumped back into the reactor. Sludge domestication can be completed in this reactor, and the microorganisms in the methanogenic bioreactor will slowly transform into granular sludge, making the reaction efficiency of this stage higher. When the reactor is actually applied, controlling the temperature in the methanogenic bioreactor within the range of 28° C. to 40° C. can make the growth environment in the reactor most suitable for the growth of methanogenic bacteria. Most of the organic matters in the nutrient solution rich in organic acids will be transformed into biogas rich in methane within 7-10 days, and the methane content is about 50%-85%. The gas can further increase the methane content after passing through gas purification devices such as water vapor separation and sulfur removal. The content of organic matter contained in the effluent water after the unit reaction is in the range of 4,000-15,000 mg/L in terms of soluble chemical oxygen demand (SCOD).

(b) membrane filter

The main function of the permeable membrane filter is to treat the effluent of the methanogenic bioreactor, keep the useful microbial bacteria in the system as much as possible without loss, and further degrade the organic matter contained in the effluent. The content of organic matter contained in the product water treated by the permeable membrane filter ranges from 1,000 to 8,000 mg/L in terms of soluble chemical oxygen demand (SCOD). The produced water will be reused in the organic waste screening machine in the pretreatment stage, so the whole system has no sewage discharge. The hydraulic retention time of the permeable membrane filter is 1 to 2 days.

The utility model also has the following beneficial effects:

(1) In the methanogenic unit, the nutrient solution is controlled to enter the methanogenic biochemical reactor, and the organic acid is converted into biogas (mainly methane and carbon dioxide) by methanogenic bacteria in the reactor.

The operating conditions and bacterial species were different in the organic decomposition unit and the methanogenic unit. The present invention controls these two groups of bacteria in two separate bioreactors in order to increase their efficiency. Also, fat or grease generated from food waste in the method using the decomposition organic matter unit is removed before the methanogenic unit to minimize disturbance to the methane process. Furthermore, separating the slow-heating methanogens in separate bioreactors can protect methanation from fluctuations in the nature of food waste and make biogas production more stable and controllable.

(2) Unlike traditional centralized food waste treatment facilities, the system developed by the utility model does not require a loaded food waste storage system. Through a pretreatment process, the expendable organic matter can be ground into small organic particles, which can be easily separated from inert matter such as animal bones, fibers, and toothpicks.

The decomposing organic matter unit of the system decomposes food waste into 3 products that can be recycled and utilized for resources, namely, waste oil, nutrient solution rich in soluble organic acids and solid residue rich in protein. Among them, waste oil can be used as raw material for the production of biodiesel; the solid residue rich in protein can be dried to become the raw material for the manufacture of environmentally friendly feed (such as fish feed); the nutrient solution rich in soluble organic acids can enter the next methane production process stage.

Each ton of food waste (based on 95% organic debris and 70% wet weight) produces about ^10-50L waste oil, about 100-200m3 containing 50%-85% biogas and about ^1-1.5m3 dry weight of about 10% to 15% wet solid residue. The wet sludge contains homogeneous organic particles which can be further processed into valuable products such as fish feed.

(3) The HRT of the decomposition reactor in the decomposition organic matter unit is 2-5 days, while the HRT of the methanation reactor in the methanation unit is 7-10 days. The total system HRT is shorter than the traditional one-step anaerobic digestion system (20-30 days), which can reduce the occupied area.

(4) Unlike traditional centralized food waste treatment facilities, which usually adopt a single-step system, the system of the present invention can control the rate of biogas generation by controlling the feeding rate of the nutrient solution into the methanogenic unit, so that Matching biogas generation and required mode to reduce biogas storage.

(5) The stability and ease of operation of the developed system does not require any skilled operations, making it very suitable for the centralized treatment of food waste from local communities, food processing factories and catering factories.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is the schematic diagram of the embodiment of the utility model recycling method;

Fig. 2 is the process flow diagram of the specific embodiment of the utility model pretreatment stage;

Fig. 3 is the process flow chart of the embodiment of the utility model decomposition organic matter stage;

Fig. 4 is the process flow chart of the specific embodiment of the methane production stage of the utility model;

Fig. 5 is a schematic diagram of the structure of the reuse system adopted in embodiment 2, wherein the symbols in the figure have the following meanings:

1: Automatic sorting organic waste screening machine; 2: Ultrasonic pretreatment machine; 3: Decomposing organic matter reactor; 4: Physical sedimentation tank; 5: Sludge drying device; 6: pH adjustment tank; 71: Methanogenic bioreactor; 72: sludge settling tank; 8: permeable membrane filter; 81: intermediate tank; 82: membrane module; 83: water production tank; 9: deodorizing device; 91: exhaust fan; 10: automatic control device.

detailed description

The utility model is further described in conjunction with the schematic diagram of FIG. 5 and the embodiment, but the content of the utility model is not limited to the following embodiment. In the examples, the experimental methods without specifying the specific conditions are conventional methods and conventional conditions well known in the art, or according to the conditions suggested by the instrument manufacturer.

Example 1

Take the garbage collected by ordinary chain tea restaurants in Hong Kong as an example to illustrate. In the garbage used in the present embodiment, except rice, porridge noodles, vegetables and meat, there is also a small amount of refractory or non-degradable garbage, such as toothpicks, bones, disposable tableware, etc. The organic waste recycling system in this embodiment is a continuous feeding mode, with a total processing capacity of 50 kg of unsorted restaurant waste per day. It has been determined that the total solid content (TS) of this type of garbage is about 20% to 40%, and the volatile solid content accounts for about 90% to 95% of the total solid content (VS/TS).

This embodiment utilizes the organic waste recycling system as shown in Figure 5, and the system includes a pretreatment unit, a decomposed organic matter unit and a methane production unit connected in sequence:

The pretreatment unit includes: an automatic classification organic waste screening machine 1 and an ultrasonic pretreatment machine 2;

The automatic sorting organic waste screening machine includes a grinding and separating device, and the grinding and separating device includes:

A cylinder, the upper part of which is provided with a feed port for the garbage to be thrown in, and the lower part of the cylinder is provided with a discharge hole;

A stirring device can be rotatably installed in the cylinder, and can grind the organic waste in the waste into organic particles by rotating and stirring;

The spraying device faces into the cylinder and can spray liquid towards the discharge hole, and the liquid carries the organic particles out of the cylinder through the discharge hole;

The decomposed organic matter unit includes a decomposed organic matter reactor 3 and a physical settling tank 4;

The methanogenic unit includes: a pH adjustment tank 6, a methanogenic bioreactor 71, a sludge settling tank 72 and a membrane filter 8;

The material outlet of the automatic classification organic waste screening machine 1 is connected with the material inlet of the ultrasonic pretreatment machine 2, and the material outlet of the ultrasonic pretreatment machine 2 is connected with the material inlet of the decomposed organic matter reactor 3; the decomposed organic matter The material outlet of the reactor 3 is connected with the material inlet of the physical sedimentation cylinder 4, the material outlet of the physical sedimentation cylinder 4 is connected with the material inlet of the pH adjustment cylinder 6, and the material outlet of the pH adjustment cylinder 6 is connected with the material outlet of the pH adjustment cylinder 6. The material inlet of the methanogenic bioreactor 71 is connected, the material outlet of the methanogenic bioreactor 71 is connected with the sludge settling tank 72, and the water outlet of the sludge settling tank 72 is connected with the permeable membrane filter connected to the water inlet;

The permeable membrane filter includes an intermediate cylinder 81, a membrane module 82 and a water production cylinder 83 connected in sequence; the material inlet of the intermediate cylinder is connected with the water outlet of the sludge settling cylinder;

The recovery system also includes a deodorizing device 9, which is respectively connected to the water production tank 83 and the ultrasonic pretreatment machine 2, and an exhaust fan 91 is arranged on the pipeline;

The water outlet of the water production tank 83 is connected with the spraying device in the automatic sorting organic waste screening machine 1 .

The system is also provided with an automatic control device 10 .

The method described in this embodiment includes the following steps:

(1) Pretreatment stage: The restaurant waste weighing about 50 kg is continuously fed into the automatic organic waste screening machine 1 in batches every day. After being processed by the screening machine, the organic matter in the waste will become the total solid content (TS) 5% to 7%, the homogeneous slurry with a solid particle diameter of about 1 to 2 mm flows out, while large pieces of refractory or non-degradable garbage such as bones, wooden chopsticks, disposable plastic tableware and other substances will temporarily remain in the Screening machine, and then regularly discharged through other discharge ports. The homogeneous slurry will then enter the ultrasonic processor 2 for further processing. The frequency range of the ultrasonic wave is set at 20-40KHz, and the hydraulic retention time of the ultrasonic processor is about 30 minutes.

(2) Decomposing organic matter stage: the pretreated homogeneous slurry will continue to flow into the decomposing organic matter reactor 3 with a slow stirrer, and the microbial bacteria that can decompose organic matter in the decomposing organic matter reactor 3 The inoculum was mixed. The concentration of the inoculum is about 10% based on the total solid content (TS), and its addition amount is about 10% of the overall volume of the reactor. The inoculum is rich in strains such as hydrolytic bacteria, fermentative bacteria, and acid-producing bacteria, and the proportion of effective strains is about 80% (the inoculum is made in the laboratory after adding water to food waste mainly composed of rice, and the total The mixture with a solid content (TS) of about 10% is placed in a closed reactor to control the temperature at about 35°C, the mechanical stirring speed is maintained at 30rpm, and the mixture is self-fermented for about 30 days). The temperature in the reactor is controlled to be about 30-40° C., the pH value is about 4-6, and the hydraulic retention time is about 3 days. When the system is initially started, part of the solid sediment after the physical settling tank settles will flow back into the reactor to increase the microbial content in the reactor. After the system was running stably for about one month, the reflux was stopped, and the homogeneous slurry in the reactor was sampled and sequenced by gene sequencing method (16S rRNA Gene Sequencing). See Table 1 below for the types and proportions of bacteria species:

Table 1

Then, the slurry will flow to the inclined-bottom physical sedimentation tank 4 with a hydraulic retention time of about 1 day for static precipitation to achieve solid-liquid separation. After the microbial bacteria in the reactor are decomposed, the pretreated slurry becomes 3 layers: The uppermost layer is waste oil, about 0.5-1 liter/day, which can be used as raw material for biodiesel after testing; the middle layer is a nutrient solution rich in organic acids with a solid content of less than 5000mg/L, about 90 liters/day, the nutrient solution will be pumped into the methanogenic bioreactor to be converted into methane-rich biogas; the lowest solid sediment is protein-rich solid residue, about 0.6-0.7 liters per day, the composition of this type of solid residue is determined to be close to that of general fish feed. Concrete each composition and the contrast of fish feed are shown in following table 2:

Table 2

(3) Methanogenic stage: According to measurements, the pH value of the nutrient solution rich in organic acids is about 4-5.5, and the soluble chemical oxygen demand (SCOD) is about 30,000-80,000 mg/L. Adjust the pH value of the nutrient solution to about 6-6.5, and then pump it regularly and quantitatively from the bottom into the methanogenic bioreactor 71 (UASB reactor), in which there is already anaerobic sludge with methanogenic bacteria (this activated sludge can come from the sludge in the anaerobic tank of the sewage station that utilizes anaerobic process to process food industry wastewater or domestic sewage, and the sludge in this embodiment comes from the sewage in the anaerobic tank of Jiujiang winery sewage station in Guangdong Province Mud), the height of the mud bed accounts for about 20% to 40% of the entire reactor. After the system was running stably for 3 months, the anaerobic activated sludge in the reactor was sampled and sequenced using the gene sequencing method (16S rRNA GeneSequencing), and the useful bacterial species contained in the sample sample in the bioreactor were found See Table 3 below for their proportions:

table 3

The temperature in the reactor is maintained at about 28-40° C. by the temperature control equipment inside the reactor, and the hydraulic retention time of the reactor is about 7-10 days. The organic matter in the water will be converted into methane-rich biogas in the reactor, which will be collected and released from the top of the UASB reactor, and then the water and hydrogen sulfide will be removed by the water-gas separation device and desulfurization device before storage and utilization. It is determined that the content of methane in the biogas is about 70%-80%, and the content of carbon dioxide is about 15%-25%. The soluble chemical oxygen demand (SCOD) in the effluent after the UASB reactor is about 5,000-15,000mg/L. After retreatment by the permeable membrane filter, the soluble chemical oxygen demand in the effluent will be further reduced to 1500-4000mg/L . All the water produced by the membrane will be reused to the organic waste screening machine in the pretreatment stage, so the whole system will have no sewage discharge.

(4) Other accessories: The main accessories of the whole recycling system are as follows:

(a) Deodorization device 9: Since the garbage will produce odor during the process of disposal, except for the methane-producing bioreactor and the permeable membrane filter in the entire recycling system, other reactors or water tanks that produce odor will be deodorized. Completely sealed treatment, this kind of odor will be pumped to a deodorization device 9 through the exhaust fan 91 for treatment, and the treated gas will be discharged into the atmosphere. For different types of garbage, chemical deodorization agents or biological filters can be selected. Deodorization is carried out in the form of a tower.

(b) Sludge drying device 5: the bottom layer of solid sediment discharged after being treated in the microbial decomposition stage is a solid residue rich in protein, which can be heated and dried by using a low-energy and high-efficiency sludge drying device 5 (such as a heat pump), It is prepared as a raw material for animal feed.

(c) Automatic control device 10: The entire recycling system will be fully automatic and run continuously for 24 hours by the automatic control device and PLC software.

The above descriptions are only specific implementation methods of the present utility model, and are not intended to limit the scope of the present utility model. It should be noted that each component of the utility model is not limited to the above-mentioned overall application, and each technical feature described in the specification of the utility model can be selected to be used alone or in combination according to actual needs. Therefore, this utility model The utility model naturally covers other combinations and specific applications related to the utility model points of this case.

Claims (8)

1. A recycling system for organic waste recycling, characterized in that: the system includes a pretreatment unit, a decomposed organic matter unit and a methane-generating unit connected in sequence: The pretreatment unit includes: an automatic classification organic waste screening machine and an ultrasonic pretreatment machine; The automatic sorting organic waste screening machine includes a grinding and separating device, and the grinding and separating device includes: A cylinder, the upper part of which is provided with a feed port for the garbage to be thrown in, and the lower part of the cylinder is provided with a discharge hole; A stirring device can be rotatably installed in the cylinder, and can grind the organic waste in the waste into organic particles by rotating and stirring; The spraying device faces into the cylinder and can spray liquid towards the discharge hole, and the liquid carries the organic particles out of the cylinder through the discharge hole; The decomposed organic matter unit includes a decomposed organic matter reactor and a physical settling tank; The methanogenic unit includes: a pH adjustment tank, a methanogenic bioreactor and a sludge settling tank; The material outlet of the automatic classification organic waste screening machine is connected with the material inlet of the ultrasonic pretreatment machine, and the material outlet of the ultrasonic pretreatment machine is connected with the material inlet of the decomposed organic matter reactor; the material of the decomposed organic matter reactor The outlet is connected with the nutrient solution inlet of the physical sedimentation tank, the nutrient solution outlet of the physical sedimentation tank is connected with the material inlet of the pH adjustment tank, and the material outlet of the pH adjustment tank is connected with the methanogenic bioreactor. The material inlet is connected; the material outlet of the methanogenic bioreactor is connected with the water inlet of the sludge settling tank. 2. The organic waste recycling system according to claim 1, characterized in that: the methane-generating unit also includes a membrane filter, and the water outlet of the sludge settling tank is connected to the outlet of the membrane filter. connected to the water inlet. 3. The organic waste resource recycling system according to claim 2, characterized in that: the permeable membrane filter includes an intermediate cylinder, a membrane module and a water production cylinder connected in sequence; the material inlet of the intermediate cylinder is connected to the The water outlet of the above sludge settling tank is connected. 4. The organic waste resource recycling system according to claim 3, characterized in that: the spray device in the automatic sorting organic waste screening machine and the water outlet of the water production tank or the physical precipitation The nutrient solution outlet of the tank is connected. 5. The organic waste recycling system according to claim 3, characterized in that: the recycling system also includes a deodorizing device, and the deodorizing device is connected with the water production tank and the ultrasonic pretreatment respectively The machine is connected by a pipeline, and an exhaust fan is installed on the pipeline. 6. The organic waste recycling system according to any one of claims 1-5, characterized in that: the reactor for decomposing organic matter is also provided with a mechanical stirring device, a pH meter and/or a temperature control device. 7. The organic waste recycling system according to any one of claims 1 to 5, characterized in that the system also includes a sludge drying device connected to the solid sediment outlet of the physical sedimentation tank . 8. The organic waste recycling system according to any one of claims 1-5, characterized in that the system further comprises an automatic control device for automating the entire system.