Method for full-amount resourceful treatment of kitchen waste coalification sewage

Abstract

The invention provides a full-amount resourceful treatment method for kitchen waste coalification sewage, according to the method, grease is obtained through oil-water separation, the grease can be used as a raw material to prepare biodiesel, and a mature process exists; the sewage subjected to oil-water separation is subjected to adsorption separation and ultrafiltration to recover residual coalification slag and the like; organic acid is extracted from the sewage passing through the ultrafiltration system by using ion exchange resin, and the organic acid can be used as a carbon source to be supplemented into a biochemical treatment process of a sewage plant, so that the denitrification effect of biochemical treatment of the sewage of the sewage plant can be improved; the sewage passing through the ion exchange resin enters a nanofiltration system to be treated, because the whole treatment process is carried out in a totally-closed mode and is free of infectious microbe infection, nanofiltration concentrated liquor is in a sterile state, and the intercepted concentrated liquor contains high-concentration carbohydrates, starch, protein and other substances. The microbial culture medium is a nutrient medium for growth and reproduction of microorganisms and mainly comprises carbohydrates, nitrogen-containing substances, inorganic salts, water and the like, so that the nanofiltration concentrated liquid can be used as a raw material of the microbial culture medium to be directly utilized in related industries of fermentation; the nanofiltration liquid passes through a reverse osmosis system, and the clear liquid reaches the reclaimed water reuse standard and is recycled, so that water resources are saved, and full-amount recycling of coalification sewage is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular to the technical field of full-scale resource treatment of kitchen waste coalification sewage. Background Art

[0002] Kitchen waste coalification refers to heating the pretreated kitchen waste to 180-250°C under anoxic conditions and stabilizing it at this temperature and pressure for 30-60 minutes. The solid-liquid separation of the obtained coalification products is coalification slag and coalification wastewater. The moisture content of kitchen waste is about 80%, and the moisture mainly exists in the form of free water and internal bound water, which provides a suitable water environment for coalification reactions such as kitchen waste hydrolysis, dehydration, and decarboxylation. Water can also be used as a solvent to increase the reaction contact area, accelerate the reaction rate, and promote the conversion of some soluble substances to the liquid phase. Sugars, starch, protein and other substances in the kitchen waste are partially dissolved. Therefore, coal chemical wastewater contains animal and plant oils and macromolecular sugars, starch, protein, amino acids, cellulose, hemicellulose, etc., as well as small molecular lactic acid, acetic acid, ethanol, butanol, esters and inorganic salts. Since the coalification temperature is much higher than the sterilization temperature and the coalification time is 30 to 60 minutes, the wastewater after coalification is sterile. In addition, the cooling temperature of coal chemical wastewater after heat exchange is 40 to 50°C; In summary, the above-mentioned sewage contains oil and is rich in nutrients with special properties. Simply treating it wastes resources and has high treatment costs. Therefore, providing a method for treating kitchen waste coal sewage with a high degree of resource utilization has become an urgent problem to be solved.

[0003] The method provided by the present invention can not only avoid the energy consumption of sewage treatment and reduce the water treatment cost, but also realize the full resource utilization of kitchen waste coalification sewage by conducting full closed treatment of kitchen waste coalification sewage to produce corresponding resource products or raw materials. Summary of the invention

[0004] The purpose of the present invention is to provide a method for the full resource treatment of kitchen waste coalification sewage, which obtains oil and fat by oil-water separation, and the oil and fat can be used as a raw material to prepare biodiesel, and there is a mature process; the sewage after oil-water separation is separated by adsorption separation and ultrafiltration to recover the residual coalification slag and the like; the sewage after the ultrafiltration system uses ion exchange resin to extract organic acid, and the organic acid can be used as a carbon source to supplement the biochemical treatment process of the sewage plant, which can improve the denitrification effect of the biochemical treatment of the sewage plant; the sewage after the ion exchange resin enters the nanofiltration system for treatment, because the whole treatment process is fully closed and there is no infection of miscellaneous bacteria, so the nanofiltration concentrate is in a sterile state, and the intercepted concentrate contains high concentrations of sugars, starch, protein and other substances. Since the microbial culture medium is a nutrient matrix for the growth and reproduction of microorganisms, it is mainly composed of carbohydrates, nitrogen-containing substances, inorganic salts and water, so the nanofiltration concentrate can be used as a raw material of the microbial culture medium for direct use by fermentation-related industries; the liquid after nanofiltration reaches the standard of water reuse through the reverse osmosis system clear liquid, which is recycled and reused, saving water resources and realizing the full resource treatment of coalification sewage.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose includes the following steps: Step 1 Oil-water separation: The temperature of kitchen waste coalification wastewater after heat exchange in the coalification system is 40-50°C, and there is a certain amount of animal and plant oils in it. Because of the high temperature, it has good fluidity without heating. The density of oil is generally between 0.91g / cm³ and 0.94g / cm³, so the oil and water separation equipment is used to separate the oil by taking advantage of the different physical properties such as the density of oil and water. The separated animal and plant oils account for 2-8% and can be used as raw materials for the production of biodiesel; Step 2 Adsorption separation: The wastewater treated in step 1 is separated and treated in an adsorption tank filled with fillers. Because the coalification wastewater will carry fine coalification slag during the solid-liquid separation process of the kitchen waste coalification product, separation and recovery are convenient for subsequent process treatment; Step 3 Ultrafiltration: The wastewater after adsorption and separation in step 2 enters the ultrafiltration system for further separation and treatment, and the unadsorbed coal slag, suspended matter, etc. are completely intercepted; Step 4: Ion exchange resin: The wastewater after ultrafiltration in step 3 is extracted through an ion exchange resin system to obtain organic acids mainly composed of lactic acid and acetic acid. The organic acids have high concentrations and can be directly used as a carbon source without pretreatment; Step 5 Nanofiltration: The wastewater after the ion exchange resin in step 4 enters the nanofiltration membrane separation and concentration system, and the percentage of nanofiltration concentrate is controlled at 15-25%. At this time, the nanofiltration concentrate contains intercepted high-concentration macromolecular sugars, starch, protein, inorganic salts, etc. Because the entire treatment process is fully closed and free of bacterial infection, the obtained nanofiltration concentrate can be used as a raw material for microbial culture medium for direct recycling by fermentation-related industries; Step 6 Reverse Osmosis: The clear liquid after nanofiltration in step 5 enters the reverse osmosis membrane separation system, and the concentrated liquid separated by the reverse osmosis system is returned to the nanofiltration system. The separated clear liquid reaches the reclaimed water reuse standard and is directly reused, thereby realizing the full resource utilization of sewage.

[0006] The above-mentioned method utilizes a method for full resource treatment of kitchen waste coalification wastewater, wherein the kitchen waste coalification wastewater is obtained by pre-treating kitchen waste under anaerobic conditions, heating at 180-250°C, and coalification for 30-60 minutes to separate the solid and liquid, and the wastewater is in a sterile state. In addition, the temperature of the coalification wastewater after heat exchange cooling is 40-50°C.

[0007] The above-mentioned method utilizes a method for fully resource-based treatment of kitchen waste coal wastewater. The kitchen waste coal wastewater treatment process is carried out in a closed manner and will not be contaminated by bacteria, so it will not ferment and produce gases such as methane and hydrogen sulfide.

[0008] The above-mentioned method utilizes a method for full resource treatment of kitchen waste coalification wastewater, and the treatment process steps of the method include: oil-water separation, adsorption separation, ultrafiltration, ion exchange resin, nanofiltration, and reverse osmosis.

[0009] The above method utilizes a method for the full resource treatment of kitchen waste coalification sewage, wherein the oil-water separation, the oily sewage separation temperature is 40-50°C, and the density of oil is between 0.91g / cm³ and 0.94g / cm³. The separated animal and plant oils account for 2-8%, and the separated oils can be used as raw materials for the production of biodiesel.

[0010] The above-mentioned method utilizes a method for full resource treatment of kitchen waste coalification wastewater, wherein the adsorption separation and ultrafiltration are performed, and the residual coalification slag separated from the wastewater is recovered and treated.

[0011] The above method utilizes a method for resource-based treatment of kitchen waste coalification wastewater, wherein the ion exchange resin and the extraction of organic acids in the wastewater select weakly alkaline anion resin, etc.

[0012] The above-mentioned method utilizes a method for fully resource-based treatment of kitchen waste coalification wastewater, and the organic acids extracted by the ion exchange resin are mainly lactic acid and acetic acid, which can be directly used as a carbon source.

[0013] The above-mentioned method utilizes a method for full resource treatment of kitchen waste coalification wastewater, in which the percentage of nanofiltration concentrate is controlled at 15-25%. At this time, the nanofiltration concentrate contains intercepted high-concentration macromolecular sugars, starch, protein, inorganic salts, etc. Because the entire treatment process is carried out in a fully closed manner and there is no infection from miscellaneous bacteria, the obtained nanofiltration concentrate can be used as a raw material for microbial culture medium for direct recycling by fermentation-related industries.

[0014] The above-mentioned method utilizes a method for resource-based treatment of kitchen waste coalification sewage in full, wherein the reverse osmosis, the concentrated liquid separated by the reverse osmosis system is returned to the nanofiltration system, and the separated clear liquid reaches the reclaimed water reuse standard and is directly reused.

[0015] The above-mentioned method utilizes a method for fully resource-based treatment of kitchen waste coalification wastewater, and the method described can save water resources and realize the full resource utilization of coalification wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of the steps of a method for fully resource-based treatment of kitchen waste coalification wastewater according to the present invention. DETAILED DESCRIPTION

[0017] Example 1 Step 1: In a kitchen waste treatment project in Shenzhen, the collected urban kitchen waste was crushed and pulped after pretreatment, and then sent to the kitchen waste coalification system for treatment. The temperature was controlled at 200℃, and the reaction lasted for 0.5h. The materials after the reaction were discharged into the heat exchanger for cooling and recycling of waste heat. The temperature of the cooled materials dropped below 45℃, and then they entered the mechanical dehydration device for solid-liquid separation, thereby obtaining coalification slag and coalification wastewater. 5T of coalification wastewater was separated into oil and water, and 0.1T of grease was separated. The density of grease was 0.92g / cm³, which was recycled by a renewable resource company as raw material for biodiesel production. After separation, 4.9T of wastewater remained; Step 2: After the oil-water separation in the first step, 4.9 tons of sewage is separated and treated by an adsorption tank filled with fillers and an ultrafiltration system, and 4.85 tons of sewage remains; Step 3: The 4.85T sewage from the second step is passed through ion exchange resin to obtain 0.1T of high-concentration organic acid, which is recycled as a carbon source in a sewage treatment plant; Step 4: After the ion exchange resin system in step 3, 4.75T of sewage enters the nanofiltration membrane separation and concentration system. The percentage of nanofiltration concentrate is 18%. The 0.855T sterile nanofiltration concentrate contains high concentrations of sugars, starch, protein, inorganic salts, etc. A fermentation industry company recycles it as a raw material for microbial culture medium, and the effect meets the relevant standards. Step 5: The wastewater after nanofiltration in the fourth step enters the reverse osmosis membrane separation system. The concentrated liquid separated by the reverse osmosis system flows back to the nanofiltration system. The separated clear liquid reaches the reclaimed water reuse standard and is directly reused, thereby realizing the full resource utilization of wastewater without secondary pollution.

[0018] Example 2 Step 1: In a kitchen waste treatment project in Shenzhen, the collected urban kitchen waste was crushed and pulped after pretreatment, and then sent to the kitchen waste coalification system for treatment. The temperature was controlled at 220℃ and the reaction lasted for 1h. The materials after the reaction were discharged into the heat exchanger for cooling and recycling of waste heat. The temperature of the cooled materials dropped below 45℃, and then they entered the mechanical dehydration device for solid-liquid separation, thereby obtaining coalification slag and coalification wastewater. 5T of coalification wastewater was separated into oil and water, and 0.2T of grease was separated. The density of grease was 0.93g / cm³, which was recycled by a renewable resource company as raw material for biodiesel production. After separation, 4.8T of wastewater remained; Step 2: After the oil-water separation in the first step, 4.8 tons of sewage is separated and treated by an adsorption tank filled with fillers and an ultrafiltration system, and 4.75 tons of sewage remains; Step 3: The 4.75T sewage from the second step is passed through ion exchange resin to obtain 0.1T of high-concentration organic acid, which is recycled as a carbon source in a sewage treatment plant; Step 4: After the ion exchange resin system in the third step, 4.65T of sewage enters the nanofiltration membrane separation and concentration system. The percentage of nanofiltration concentrate is 20%. The 0.93T sterile nanofiltration concentrate contains high concentrations of sugars, starch, protein, inorganic salts, etc. A fermentation industry company recycles it as a raw material for microbial culture medium, and the effect meets the relevant standards; Step 5: The wastewater after nanofiltration in the fourth step enters the reverse osmosis membrane separation system. The concentrated liquid separated by the reverse osmosis system flows back to the nanofiltration system. The separated clear liquid reaches the reclaimed water reuse standard and is directly reused, thereby realizing the full resource utilization of wastewater without secondary pollution.

[0019] Example 3 Step 1: In a kitchen waste treatment project in Shenzhen, the collected urban kitchen waste was crushed and pulped after pretreatment, and then sent to the kitchen waste coalification system for treatment. The temperature was controlled at 200℃ and the reaction lasted for 1h. The materials after the reaction were discharged into the heat exchanger for cooling and recycling of waste heat. The temperature of the cooled materials dropped below 45℃, and then they entered the mechanical dehydration device for solid-liquid separation, thereby obtaining coalification slag and coalification wastewater. 5T of coalification wastewater was separated into oil and water, and 0.2T of grease was separated. The density of grease was 0.92g / cm³, which was recycled by a renewable resource company as raw material for biodiesel production. After separation, 4.8T of wastewater remained; Step 2: After the oil-water separation in the first step, 4.8 tons of sewage is separated and treated by an adsorption tank filled with fillers and an ultrafiltration system, and 4.75 tons of sewage remains; Step 3: The 4.75T sewage from the second step is passed through ion exchange resin to obtain 0.1T of high-concentration organic acid, which is recycled as a carbon source in a sewage treatment plant; Step 4: After the ion exchange resin system in the third step, 4.65T of sewage enters the nanofiltration membrane separation and concentration system. The percentage of nanofiltration concentrate is 20%. The 0.93T sterile nanofiltration concentrate contains high concentrations of sugars, starch, protein, inorganic salts, etc. A fermentation industry company recycles it as a raw material for microbial culture medium, and the effect meets the relevant standards; Step 5: The wastewater after nanofiltration in the fourth step enters the reverse osmosis membrane separation system. The concentrated liquid separated by the reverse osmosis system flows back to the nanofiltration system. The separated clear liquid reaches the reclaimed water reuse standard and is directly reused, thereby realizing the full resource utilization of wastewater without secondary pollution.

Claims

1. The present invention discloses a method for the full resource treatment of kitchen waste coalification sewage, which is characterized by: The treatment process steps of the method include oil-water separation, adsorption separation, ultrafiltration, ion exchange resin, nanofiltration, and reverse osmosis.

2. The method for recycling kitchen waste coal wastewater according to claim 1, characterized in that: The kitchen waste coalification wastewater is obtained by heating the pre-treated kitchen waste at 180-250°C under anoxic conditions, coalifying it for 30-60 minutes, and then separating the solid and liquid. The wastewater is sterile, and the temperature of the coalification wastewater after heat exchange cooling is 40-50°C.

3. The method for resource-based treatment of kitchen waste coalification sewage according to claim 1, characterized in that: The kitchen waste coalification sewage treatment process is carried out in a closed manner and will not be contaminated by bacteria, so it will not ferment and produce gases such as methane and hydrogen sulfide.

4. The method for resource-based treatment of kitchen waste coalification sewage according to claim 1, characterized in that: The oil-water separation and oily wastewater separation temperature are 40-50°C, and the density of oil and fat ranges from 0.91g / cm³ to 0.94g / cm³. Separated animal and plant oils account for 2-8% and the separated oils can be used as raw materials for producing biodiesel.

5. The method for full resource treatment of kitchen waste coalification sewage according to claim 1, characterized in that: The adsorption separation and ultrafiltration are used to recover and treat the residual coal slag separated from the sewage.

6. The method for full resource treatment of kitchen waste coalification sewage according to claim 1, characterized in that: The ion exchange resin used to extract organic acids from sewage is a weakly alkaline anion resin.

7. The method for full resource treatment of kitchen waste coalification sewage according to claim 1, characterized in that: The organic acids extracted by the ion exchange resin are mainly lactic acid and acetic acid, which can be directly used as carbon sources.

8. The method for full resource treatment of kitchen waste coalification sewage according to claim 1, characterized in that: In the nanofiltration, the percentage of nanofiltration concentrate is controlled at 15-25%. At this time, the nanofiltration concentrate contains intercepted high-concentration macromolecular sugars, starch, protein, inorganic salts, etc. Because the entire treatment process is fully closed and free of bacterial infection, the obtained nanofiltration concentrate can be used as a raw material for microbial culture medium for direct recycling by fermentation-related industries.

9. The method for full resource treatment of kitchen waste coalification sewage according to claim 1, characterized in that: The reverse osmosis system separates the concentrated liquid which is refluxed to the nanofiltration system, and the separated clear liquid reaches the reclaimed water reuse standard and is directly reused.

10. The method for full resource treatment of kitchen waste coalification sewage according to claim 1, characterized in that: The method described can save water resources and realize the full resource utilization of coal chemical wastewater.

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