CN115678922A - Process for directionally preparing VFAs organic acid by resourceful treatment of kitchen garbage - Google Patents
Process for directionally preparing VFAs organic acid by resourceful treatment of kitchen garbage Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel
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- Processing Of Solid Wastes (AREA)
Abstract
The invention discloses a process for preparing VFAs organic acids by recycling kitchen garbage, which belongs to the technical field of preparing the VFAs organic acids by the kitchen garbage. The technology of the invention utilizes the influence of pH on the biological activity of the microorganism to inhibit the growth of methanogenic microorganisms, so that only acidifying bacteria can maintain the activity to continuously produce volatile organic acid (VFA), and the aim of directionally preparing the volatile organic acid all the year without season is achieved. The VFAs organic acid can be used as a raw material to produce the degradable plastic material PHA, can also be used as a carbon source to be added into a water purification plant to participate in a sewage denitrification treatment process, and has double economic benefits of 'open source' and 'closure' for the field of kitchen garbage treatment.
Description
Technical Field
The invention relates to the technical field of preparing VFAs organic acids from kitchen waste, in particular to a process for directionally preparing the VFAs organic acids by recycling the kitchen waste.
Background
The kitchen waste treatment process mainly comprises anaerobic fermentation, aerobic composting, direct drying for making feed, a microbial treatment technology, an insect source protein feed biotransformation technology and a cooperative resource treatment technology.
The mechanical crushing direct discharging method is that the household garbage crusher is used to crush the household kitchen garbage and the crushed garbage is discharged into a municipal sewer network. Directly increased municipal water purification factory's processing load, the kitchen is surplus immediately grease content high, easily condenses the piece in drainage pipe, accumulates to cause the jam problem to the sewage pipe network along with the time. And the kitchen garbage is easy to be left in the pipeline, so that odor is generated, the environment is polluted, and the breeding chances of germs, mosquitoes and flies and the spreading chances of diseases are increased.
The high-temperature aerobic composting technology is a process of composting kitchen garbage under the condition of manual control to ensure that organic solid waste is biologically stabilized. The products of the aerobic composting are unsmooth, are greatly influenced by seasons and climates, have high long-distance transportation cost, cause odor pollution to compost treatment facilities to disturb residents, have large occupied area and the like.
The anaerobic fermentation treatment technology is to treat kitchen garbage by using microorganisms under the high-temperature anaerobic condition to decompose and convert organic substances in the kitchen garbage into methane, carbon dioxide, fermentation residues and the like. The requirement on the pH value of the kitchen waste is high, the technical control is complex, the biological start time of the reactor is long, biogas residues generated by anaerobic fermentation need to be further treated, the C/N of the biogas slurry is low, and the treatment difficulty is high.
The insect transformation treatment technology is to decompose and transform organic matters in the kitchen garbage through the synergistic effect of the insects such as earthworm, hermetia illucens and tenebrio molitor and microorganisms. High-content grease and inorganic substances in the kitchen waste have negative influence on the decomposition of organic matters by insects, so before the kitchen waste insects are treated, careful oil and slag removal work needs to be carried out, and the treatment workload is increased. The insect transformation treatment technology has the problems that the insect breeding base occupies a large area, is obviously changed by seasonal climate, residual residues after insect decomposition need to be further treated, odor is easy to generate and the like.
Kitchen waste (including household kitchen waste) is the most main component of organic solid waste after the classification of household waste, and is also the most main carrier of organic carbon in the household waste. The kitchen waste has obvious resource and waste duality, and is easy to emit peculiar smell, pollute the environment and generate high-concentration organic wastewater when being not treated well.
The anaerobic fermentation for producing biogas is a mainstream kitchen waste recycling technology, the biogas generated by anaerobic fermentation treatment of the kitchen waste can be used for power generation, biogas residues can be treated according to solid waste, and the difficulty in biogas slurry treatment is high. The biogas slurry has the characteristics of high pollutant concentration, complex components, high ammonia nitrogen content and inconsistent carbon-nitrogen ratio, and the high-concentration nitrogen is difficult to remove and treat and the treatment process is long.
The problem that kitchen waste treatment facilities are easy to encounter the 'neighborhood effect' when being selected, and fermentation biogas slurry is difficult to treat objectively restricts the improvement of the treatment capacity and level of urban kitchen waste, and a new technical route and a treatment scheme with strong applicability need to be explored.
Most of traditional carbon sources are liquid or soluble substances, and in the actual adding process, due to fluctuation of the water quality of inlet water, the adding is easy to cause the condition of insufficient or excessive adding, so that the water quality of outlet water cannot stably reach the standard, and the sewage treatment cost is further increased. In recent years, many researchers turn to research on developing carbon sources which are high in environmental safety, low in cost and even capable of treating wastes with wastes, and the novel carbon sources mainly comprise liquid carbon sources mainly comprising industrial wastewater, sludge, kitchen waste hydrolysate and garbage leachate. Wherein, the digestive solution or the hydrolysate which is rich in Volatile Fatty Acid (VFA) is adopted to provide a carbon source, the biodegradability is good, the toxic and side effect is less, the problem of low carbon-nitrogen ratio in the original sewage is solved, and the resource utilization of the waste water can be realized.
Disclosure of Invention
The invention aims to provide a process for directionally preparing VFAs organic acids by utilizing the resource treatment of kitchen waste, so as to solve the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme: the process for directionally preparing the VFAs organic acid by recycling the kitchen garbage comprises the following steps: the method comprises the following steps:
s1: pouring kitchen fruit and vegetable garbage into a garbage receiving tank;
s2: crushing garbage bags in the kitchen Yu Guo vegetable garbage through a bag crushing device, conveying the garbage bags into a coarse crushing and sorting system through a hydraulic flow control device, performing coarse crushing on kitchen, fruit and vegetable garbage and screening out impurities with the particle size larger than 100 mm;
s3: conveying the coarsely crushed kitchen fruit and vegetable garbage into a gravity winnowing device, and sieving heavy impurities with the particle size of more than 10mm and less than 100 mm;
s4: conveying the kitchen waste, fruit and vegetable wastes from which the heavy impurities are removed into a fine pulping device, screening out light impurities with the particle size of less than 10mm, and preparing kitchen waste, fruit and vegetable waste pulp;
s5: conveying the kitchen waste, fruit and vegetable waste pulp subjected to light impurity removal to a pulp temporary storage pool, selecting whether backflow tempering is needed according to the pulp condition, if so, returning the pulp to a waste receiving tank for backflow tempering and repeating the steps, and if not, entering the step S6;
s6: conveying the kitchen fruit and vegetable waste slurry in the slurry temporary storage pool to an oil and sand removing device to remove floating oil and partial fine and heavy impurities, conveying the slurry to a hydrolysis reactor for hydrolysis, and conveying the slurry to an acidification reactor for acidification;
s7: conveying the kitchen fruit and vegetable waste slurry after acidification in the acidification reactor to a VFAs preparation reactor for directionally preparing VFAs organic acid, removing fine and light impurities through a scum extrusion device, and finally conveying the VFAs organic acid to an acidification discharge temporary storage tank;
s8: the VFAs organic acid in the acidification discharge temporary storage pool is detected according to water quality indexes, when the indexes meet the requirements of the VFAs organic acid, the step S9 is carried out, otherwise, the VFAs organic acid is refluxed and tempered ， Conveying the VFAs organic acid in the acidified discharging temporary storage pool into a slurry temporary storage pool for VFAs organic acid backflow tempering, and repeating the steps S6-S7;
s9: and purifying the VFAs organic acid in the acidification discharge temporary storage tank by a VFA ultrafiltration purification device, and then conveying the organic acid into a carbon source discharge temporary storage tank for transporting and supplementing a carbon source.
Preferably, in the step S2, the removed coarse impurities are transported to an outside for incineration to generate electricity.
Preferably, in the step S2, impurities which are difficult to break in the kitchen waste, fruit and vegetable, and garbage slurry crushed by the coarse crushing and sorting system are conveyed to an impurity extruding device, and the impurities are extruded to remove excessive water and then discharged, and are transported to an outside for incineration and power generation.
Preferably, in the step S3, the removed heavy impurities are added into an impurity squeezing device, and the impurities are squeezed to remove excess moisture and then discharged, and are transported to an external incineration facility for power generation.
Preferably, in the step S4, the removed light impurities are added into an impurity squeezing device, and the impurities are discharged after squeezing excess water, and are transported to an external incineration for power generation.
Preferably, in the steps S6 and S7, the removed fine and heavy impurities and fine and light impurities are added into an impurity squeezing device, and the impurities are squeezed to remove excess moisture and then discharged, and are transported to an outside for incineration and power generation.
Preferably, in step S6, the hydrolysis acidification reaction time is 7-10 days.
Preferably, in the step S7, the reaction conditions for preparing VFAs organic acids are optimized: pH3.8-4.8; the temperature is 20-30 ℃; suspension 4.0X 10 4 ～6.0×10 4 mg/L。
Preferably, in step S8, the COD of VFAs organic acids in the acidification treatment temporary storage tank is detected to be less than 8.0X 10 4 And mg/L, refluxing the VFAs organic acid in the acidified discharging temporary storage tank to the slurry temporary storage tank for tempering.
Compared with the prior art, the invention has the beneficial effects that:
1) The Volatile Fatty Acid (VFA) is one of fatty acids, can be used as a carbon source to produce degradable plastic material Polyhydroxyalkanoate (PHA), and can also be used as a carbon source to be added into a town water purification plant to replace a chemical carbon source to participate in a sewage denitrification treatment process;
2) The kitchen waste is the most main carrier of organic carbon in the household garbage of residents, and hydrolysate generated after the kitchen waste is further hydrolyzed and acidified is rich in short-chain micromolecular organic carbon up to tens of thousands of milligrams per liter and is a high-quality raw material serving as a carbon source;
3) The technology of the invention utilizes the influence of pH value on the biological activity of microorganisms to inhibit the growth of methanogenic microorganisms, so that only acidifying bacteria can maintain the activity to continuously produce volatile organic acid (VFA), the aim of non-seasonal directional preparation of volatile organic acid all the year is achieved, the VFA is used as a carbon source, the degradable plastic material PHA can be industrially produced, the carbon source can also be used as a carbon source to be added into a water purification plant to participate in a sewage denitrification treatment process, the investment and the operating cost of kitchen garbage treatment are reduced, the economic value of the kitchen garbage resource utilization is improved, and the double economic benefits of 'source opening' and 'cut-off' are achieved;
4) The process only adopts an efficient hydrolysis acidification technology to inhibit anaerobic methane production and directionally prepare the volatile organic acid, no reagent is added in the process for reaction catalytic regulation, and then the volatile organic acid is used as a supplementary carbon source of the municipal sewage, so that the utilization level of kitchen waste resources is improved, and the treatment cost of the municipal sewage is reduced;
5) The process for directionally preparing the VFAs organic acid by recycling the kitchen waste is blank in the industry at present, and belongs to the technical route of the original process.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a schematic representation of the preparation of VFAs organic acids in accordance with the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top/bottom", etc. indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings, which are merely for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "provided", "fitted/connected", "connected", and the like, are to be interpreted broadly, such as "connected", which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example (b):
referring to fig. 1-2, the present invention provides a technical solution: the process for directionally preparing the VFAs organic acid by utilizing the resource treatment of the kitchen garbage comprises the following steps: the method comprises the following steps:
s1: pouring kitchen fruit and vegetable garbage into a garbage receiving tank;
s2: crushing garbage bags in the kitchen Yu Guo vegetable garbage through a bag crushing device, conveying the garbage bags into a coarse crushing and sorting system through a hydraulic flow control device, performing coarse crushing on kitchen, fruit and vegetable garbage and screening out impurities with the particle size larger than 100 mm;
s3: conveying the coarsely crushed kitchen fruit and vegetable garbage into a gravity winnowing device, and sieving heavy impurities with the particle size of more than 10mm and less than 100 mm;
s4: conveying the kitchen waste, fruit and vegetable, and kitchen waste, from which the heavy impurities are removed, into a fine pulping device, screening out light impurities with the particle size of less than 10mm, and preparing kitchen waste, fruit and vegetable, and kitchen waste pulp;
s5: conveying the kitchen waste, fruit and vegetable waste pulp subjected to light impurity removal to a pulp temporary storage pool, selecting whether backflow tempering is needed according to the pulp condition, if so, returning the pulp to a waste receiving tank for backflow tempering and repeating the steps, and if not, entering the step S6;
s6: conveying the kitchen fruit and vegetable waste slurry in the slurry temporary storage pool to an oil and sand removing device to remove floating oil and partial fine and heavy impurities, conveying the slurry to a hydrolysis reactor for hydrolysis, and conveying the slurry to an acidification reactor for acidification;
s7: conveying the kitchen fruit and vegetable waste slurry after acidification in the acidification reactor to a VFAs preparation reactor for directionally preparing VFAs organic acid, removing fine and light impurities through a scum extrusion device, and finally conveying the VFAs organic acid to an acidification discharge temporary storage tank;
s8: detecting the VFAs organic acid in the acidification discharge temporary storage pool according to water quality indexes, entering the step S9 when the indexes meet the requirements of the VFAs organic acid, and otherwise, carrying out backflow tempering on the VFAs organic acid ， The VFAs in the acidification discharge temporary storage tank haveConveying the organic acid to a slurry temporary storage pool for VFAs organic acid backflow tempering, and repeating the steps S6-S7;
s9: and purifying the VFAs organic acid in the acidification discharge temporary storage tank by a VFA ultrafiltration purification device, and then conveying the organic acid into a carbon source discharge temporary storage tank for transporting and supplementing a carbon source.
And in the step S2, the removed coarse impurities are transported to the outside for incineration and power generation.
And in the step S2, impurities which are difficult to crush in the kitchen fruit and vegetable waste slurry crushed by the coarse crushing and sorting system are conveyed to an impurity extruding device, the impurities are extruded to remove redundant moisture and then are discharged, and the impurities are transported to an outside for incineration and power generation.
And in the step S3, the removed heavy impurities are added into an impurity extruding device, the impurities are extruded to remove redundant moisture and then are discharged, and the impurities are transported to be incinerated for power generation.
And in the step S4, the removed light impurities are added into an impurity extruding device, the impurities are extruded to remove redundant water and then are discharged, and the impurities are transported to burn for power generation.
And in the steps S6 and S7, the removed fine and heavy impurities and the removed fine and light impurities are added into an impurity extruding device, the impurities are extruded to remove excessive water and then are discharged, and the impurities are transported to be incinerated for power generation.
In the step S6, the time of the hydrolysis acidification reaction is 7-10 days.
In the step S7, the optimal reaction conditions for directionally preparing the VFAs organic acid are as follows: pH3.8-4.8; the temperature is 20-30 ℃; suspension 4.0X 10 4 ～6.0×10 4 mg/L。
In the step S8, the COD of the VFAs organic acids in the temporary storage tank after acidification treatment is less than 8.0 multiplied by 10 through detection 4 And mg/L, refluxing the VFAs organic acid in the acidified discharging temporary storage tank to the slurry temporary storage tank for tempering.
The kitchen garbage is treated by recycling, and an innovative process technology of 'pretreatment, separation and pulping and preparation of organic acid by acidification of slurry' is adopted. In the pretreatment, separation and pulping stage, inorganic substances which cannot be utilized in kitchen waste and impurities which cannot be crushed and have the particle size larger than 100mm are separated and stripped, and utilized grease and partial slag materials with the particle size larger than 5mm are screened out and used for preparing biofuel, biopharmaceutical and the like. And (4) homogenizing the slurry with the diameter of less than 5mm, and then entering a high-efficiency hydrolysis acidification and directional acid preparation stage.
The acidifying bacteria are colony names capable of generating acidifying fermentation reactions, wherein the colony groups are complex, metabolites of different acidifying bacteria are different, for example, acetate metabolites generate acetic acid, and lactic acid bacteria metabolites generate lactic acid, so that complex and various short-chain volatile fatty acids can be generated after the kitchen garbage is converted in an acidifying stage.
VFAs (volatile fatty acids) organic acids, mainly including acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, etc., all of which are volatile. The volatile fatty acid can be used for producing the degradable plastic material polyhydroxyalkanoate PHA, is easy to be directly utilized by microorganisms due to the short-chain molecular structure of the polyhydroxyalkanoate PHA, and provides energy for the metabolism of the microorganisms.
VFA generally refers to short chain fatty acids having 1 to 6 carbon atoms, and is a generic term, and acetic acid, propionic acid, butyric acid, etc. are all included therein. Therefore, the high-concentration VFA organic acid product with one short-chain fatty acid as the main component in the VFA organic acid can be obtained by artificially controlling the temperature, pH, SS and other bacteria growth environmental conditions in the VFA reactor, thereby highlighting the directionality of the technical process for directionally preparing the VFAs organic acid. For example, the conditions of temperature of 28 to 33 ℃ and pH of 3.5 to 6.5 are most suitable for the growth of acetic acid bacteria; therefore, if the environmental conditions are controlled under the condition parameters by human intervention, the acetic acid bacteria rapidly grow and reproduce in the VFA reactor, occupy the dominance of bacterial colonies and become main flora and dominant flora; correspondingly, acetic acid is produced by the metabolism of the acetobacter to become VFAs organic acids with the highest proportion in metabolites, and the content of the acetic acid in the prepared VFAs organic acids can reach 80%.
As shown in figure 2, the process adopts a hydrolysis acidification staged fermentation degradation method, takes kitchen waste as a raw material, and converts long-chain macromolecular organic acid in the kitchen waste into short-chain micromolecular organic acid through the combined action of hydrolytic bacteria and acidifying bacteria. In order to achieve the purpose of high-efficiency hydrolytic acidification, the slurry has enough residence time in the hydrolytic reactor and the acidification reactor, and the hydrolytic acidification reaction time is preferably 7-10 days in total, so that the slurry can quickly reduce the pH value to 3.8-4.8 under the action of the acidification bacteria. Under the condition of the pH value, the aims of improving the VFAs partial pressure, the hydrogen partial pressure and the carbon monoxide partial pressure in the VFAs reactor can be fulfilled, and the growth of methanogenic microorganisms is inhibited, so that only acidifying bacteria can maintain the activity to continuously produce acid.
The optimal pH value for the growth of the methane bacteria is between 6.8 and 7.2, and when the pH value deviates from the pH range, the pH value can generate an inhibiting effect on the growth of the methane bacteria, and the inhibiting effect is more obvious when the pH value deviates far; the pH range of 3.8-4.8 is the optimal living environment of the acidifier, the acidifier can quickly grow and reproduce, but the growth of the methane bacteria can be inhibited due to environmental discomfort, so that the aim of inhibiting the growth of the methane bacteria is fulfilled. Thus, the VFAs production reactor is operated at a temperature of 20 to 30 ℃ and a pH of 3.8 to 4.8.
The acidified kitchen waste slurry is introduced into a VFAs preparation reactor, the metabolism of various VFA strains of the VFAs reactor is enhanced through regulating and controlling the parameters in the VFAs reactor, the concentration of VFAs (volatile fatty acids) organic acids is increased, and the VFAs organic acids account for more than 90% of the total organic carbon. Or changing the environmental conditions in the reactor according to the known conditions to generate the competitive effect of 'superior and inferior elimination' among VFA strains, thereby achieving the organic acid product which takes a certain short-chain fatty acid as the main component.
For wastewater with high ammonia nitrogen and low carbon nitrogen ratio, when the carbon source of inlet water is insufficient, the enhanced denitrification reaction and the improvement of the total nitrogen removal rate are necessary for the integral operation of a water quality purification plant. In order to achieve a good denitrification effect in the conventional biological denitrification process, methanol, acetic acid, glucose and the like are usually added as carbon sources. The traditional biological denitrification process means that nitrogen-containing compounds sequentially undergo three reactions of ammoniation, nitrification and denitrification under the action of microorganisms, so that the aim of denitrification is fulfilled. The nitrification process requires aeration and consumes energy, and the energy consumption of the nitrification process can be up to 50 percent in the energy consumption of a typical urban sewage plant. In addition, the carbon source required in denitrification is usually consumed in a large amount in the nitrification process, and a large amount of carbon source needs to be additionally added. In order to achieve a proper denitrification rate and a good denitrification effect, a carbon source is added according to 2-3 times of theoretical consumption. In addition, in order to maintain higher biological concentration in the system and obtain good denitrification effect, the return of sludge and nitrified liquid must be carried out simultaneously, and the power consumption and the operating cost are increased. Volatile Fatty Acids (VFAs) are one type of fatty acid that are highly volatile and are therefore called volatile fatty acids. The volatile fatty acid can be used as a carbon source to produce degradable plastic material Polyhydroxyalkanoate (PHA) and can also be used as a carbon source to be added into a town water purification plant to replace a chemical carbon source to participate in a sewage denitrification treatment process.
The VFAs organic acids belong to short-chain organic acids, and the short-chain organic acids are required to be used as a supplementary carbon source in the sewage treatment process of a water quality purification plant, so that the VFAs organic acids directionally prepared by the method can be used as the supplementary carbon source to be supplied to the water quality purification plant.
The technology inhibits anaerobic methanogenesis by regulating and controlling the operation parameters of the VFAs reactor, achieves the aim of directionally preparing acid, and breaks through the spontaneous methanogenesis theory of the anaerobic fermentation process. Regulating pH value to 3.8-4.8, regulating temperature to 20-30 deg.C, and regulating SS value to 4 × 10 4 -6×10 4 In the mg/L interval, methanogenic bacteria can not grow in the reactor, and the acidified kitchen waste slurry enters the reactor and can not spontaneously carry out fermentation methanogenesis reaction.
While there have been shown and described the fundamental principles and essential features of the invention and advantages thereof, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof; the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not to be construed as limiting the claims.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (9)
1. The process for directionally preparing the VFAs organic acid by utilizing the resource treatment of the kitchen garbage comprises the following steps: the method is characterized in that: the method comprises the following steps:
s1: pouring kitchen fruit and vegetable garbage into a garbage receiving tank;
s2: crushing garbage bags in the kitchen Yu Guo vegetable garbage through a bag crushing device, conveying the garbage bags into a coarse crushing and sorting system through a hydraulic flow control device, performing coarse crushing on kitchen, fruit and vegetable garbage and screening out impurities with the particle size larger than 100 mm;
s3: conveying the coarsely crushed kitchen fruit and vegetable garbage into a gravity winnowing device, and sieving heavy impurities with the particle size of more than 10mm and less than 100 mm;
s4: conveying the kitchen waste, fruit and vegetable wastes from which the heavy impurities are removed into a fine pulping device, screening out light impurities with the particle size of less than 10mm, and preparing kitchen waste, fruit and vegetable waste pulp;
s5: conveying the kitchen waste, fruit and vegetable, and vegetable waste pulp without light impurities to a pulp temporary storage pool, selecting whether backflow tempering is needed according to the pulp condition, if so, returning the pulp to a waste receiving groove for backflow tempering, and repeating the steps, and if not, entering the step S6;
s6: conveying the kitchen fruit and vegetable waste slurry in the slurry temporary storage pool to an oil and sand removing device to remove floating oil and partial fine and heavy impurities, conveying the slurry to a hydrolysis reactor for hydrolysis, and conveying the slurry to an acidification reactor for acidification;
s7: conveying the kitchen fruit and vegetable waste slurry after acidification in the acidification reactor to a VFAs preparation reactor for directionally preparing VFAs organic acid, removing fine and light impurities through a scum extrusion device, and finally conveying the VFAs organic acid to an acidification discharge temporary storage tank;
s8: detecting the VFAs organic acid in the acidification discharge temporary storage pool according to water quality indexes, entering step S9 when the indexes meet the requirements of the VFAs organic acid, otherwise, carrying out VFAs organic acid backflow tempering, conveying the VFAs organic acid in the acidification discharge temporary storage pool to the slurry temporary storage pool for carrying out VFAs organic acid backflow tempering, and repeating the steps S6-S7;
s9: and purifying the VFAs organic acid in the acidification discharge temporary storage tank by a VFA ultrafiltration purification device, and then conveying the organic acid into a carbon source discharge temporary storage tank for transporting and supplementing a carbon source.
2. The process for directionally preparing VFAs organic acids by utilizing kitchen garbage resource treatment as claimed in claim 1, wherein: and in the step S2, the removed coarse impurities are transported to the outside for incineration and power generation.
3. The process for the directional preparation of VFAs organic acids by the resource recovery treatment of kitchen waste as claimed in claim 1, wherein: and in the step S2, impurities which are difficult to crush in the kitchen fruit and vegetable waste slurry crushed by the coarse crushing and sorting system are conveyed to an impurity extruding device, the impurities are extruded to remove redundant moisture and then are discharged, and the impurities are transported to an outside for incineration and power generation.
4. The process for the directional preparation of VFAs organic acids by the resource recovery treatment of kitchen waste as claimed in claim 1, wherein: and in the step S3, the removed heavy impurities are added into an impurity extruding device, the impurities are extruded to remove redundant moisture and then are discharged, and the impurities are transported to be incinerated for power generation.
5. The process for directionally preparing VFAs organic acids by utilizing kitchen garbage resource treatment as claimed in claim 1, wherein: and in the step S4, the removed light impurities are added into an impurity extruding device, the impurities are extruded to remove redundant moisture and then are discharged, and the impurities are transported to be incinerated for power generation.
6. The process for the directional preparation of VFAs organic acids by the resource recovery treatment of kitchen waste as claimed in claim 1, wherein: and in the steps S6 and S7, the removed fine and heavy impurities and the removed fine and light impurities are added into an impurity extruding device, the impurities are extruded to remove redundant water and then are discharged, and the impurities are transported to be incinerated for power generation.
7. The process for the directional preparation of VFAs organic acids by the resource recovery treatment of kitchen waste as claimed in claim 1, wherein: in the step S6, the time of the hydrolysis acidification reaction is 7-10 days.
8. The process for the directional preparation of VFAs organic acids by the resource recovery treatment of kitchen waste as claimed in claim 1, wherein: in the step S7, the optimal reaction conditions for directionally preparing the VFAs organic acid are as follows: pH3.8-4.8; the temperature is 20-30 ℃; suspension 4.0X 10 4 ～6.0×10 4 mg/L。
9. The process for directionally preparing VFAs organic acids by utilizing kitchen garbage resource treatment as claimed in claim 1, wherein: in the step S8, the COD of the VFAs organic acids in the temporary storage tank after acidification treatment is less than 8.0 multiplied by 10 through detection 4 And mg/L, refluxing VFAs organic acid in the acidified discharging temporary storage tank to the slurry temporary storage tank for tempering.
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