Three-phase kitchen water treatment method and system

Abstract

The invention discloses a method and system for treating three-phase water from kitchen and dining room. The method comprises: collecting three-phase water and conveying it to a hydrolysis and acidification device, adding anaerobic biogas slurry to the hydrolysis and acidification device, and hydrolyzing and acidifying it for 3 to 4 days; conveying the three-phase water after hydrolysis and acidification to an ammonia device, and ammoniating it for 1 to 3 days to obtain the three-phase water after ammonia; filtering the three-phase water after ammonia to obtain a filtrate; pumping the filtrate into an ultrafiltration membrane system for ultrafiltration, and using the clear liquid of the membrane effluent as an external carbon source in a sewage treatment biochemical system, and the concentrated liquid is refluxed. The invention makes full use of the resources in the three-phase water from kitchen and dining room to prepare a carbon source product, which has a high VFA content, a high ammonia nitrogen / total nitrogen content, and a low solid suspended matter content. When the carbon source can be directly used as an external carbon source in a sewage treatment biochemical system, the sewage treatment cost can be reduced and the system operation stability can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of three-phase kitchen water treatment, and in particular to a three-phase kitchen water treatment method and system. Background Art

[0002] Currently, the carbon sources for biochemical treatment processes of sewage treatment on the market include methanol, glucose, biomass carbon sources, etc.; among them, methanol is the most commonly used, but the cost of methanol as a chemical agent is relatively high, and methanol has certain toxicity when used for a long time; using glucose as a carbon source will lead to an increase in sludge, increase the COD of the effluent, and is more likely to produce nitrite nitrogen accumulation; and the stability of biomass carbon sources is poor, and the COD level needs to be tested before use.

[0003] Therefore, seeking a simple, efficient and cheap carbon source has become an effective way to reduce sewage treatment costs and operating costs.

[0004] In addition, the inventors of the present application also noticed that the water quality is complex, the carbon-nitrogen ratio is seriously unbalanced, and the treatment difficulty is increased during the sewage treatment process. For example, the leachate generated from the landfill, especially the leachate after the closure of the aging landfill, the ammonia nitrogen content reaches a peak during the landfill cycle, while the COD is further reduced, resulting in a serious imbalance in the carbon-nitrogen ratio; the traditional nitrification and denitrification process can only rely on the large-scale addition of external carbon sources to ensure operation, which not only has high operating costs, but also unstable operation and poor system resistance to shock loads. Summary of the invention

[0005] According to one embodiment of the present invention, the purpose is to provide a method and system for treating three-phase water from kitchens and restaurants. The carbon source resources in the three-phase water from kitchens and restaurants are fully utilized to prepare a carbon source product with high VFA content, high ammonia nitrogen / total nitrogen, and low suspended solids content. When the carbon source is used as an external carbon source in a sewage treatment biochemical system, the sewage treatment cost can be reduced, the system treatment burden can be reduced, and the system operation stability can be improved.

[0006] The above purpose can be achieved by implementing the following technical solutions:

[0007] According to one aspect of the present invention, the present invention provides a method for treating three-phase kitchen water, comprising:

[0008] Collect the three-phase water from the kitchen and send it to the hydrolysis and acidification equipment, add anaerobic biogas slurry, and hydrolyze and acidify for 3 to 4 days; send the three-phase water after hydrolysis and acidification to the ammoniation equipment, ammoniate for 1 to 3 days, and obtain the ammoniated three-phase water;

[0009] The three-phase water after ammoniation is subjected to multi-stage filtration to obtain a filtrate; the filtrate is pumped into an ultrafiltration membrane system for ultrafiltration, and the clear liquid out of the membrane is the carbon source product, which is used as an external carbon source in a wastewater treatment biochemical system, and the concentrated liquid is refluxed to the hydrolysis acidification equipment.

[0010] Optionally, the anaerobic biogas slurry refers to the biogas slurry obtained by anaerobic fermentation of three-phase water in an anaerobic digestion system to produce biogas.

[0011] Optionally, the method further includes: collecting three-phase kitchen water and sending it to an anaerobic digestion system for anaerobic fermentation to produce biogas, and storing the fermented anaerobic biogas slurry in a biogas slurry tank.

[0012] Optionally, in the hydrolysis and acidification equipment, the ratio of three-phase kitchen water to anaerobic biogas slurry is: 9: (1-2.5).

[0013] Optionally, during hydrolysis and acidification, the pH value is controlled to be 6.5-7.0 and the temperature is 30°C-40°C.

[0014] Optionally, during the ammoniation treatment, the pH value is controlled to be 6.5-7.0 and the temperature is controlled to be 30° C.-40° C.

[0015] Optionally, the step of sequentially performing multi-stage filtration on the ammoniation three-phase water comprises:

[0016] The ammoniated solution is deslagging by a deslagging machine; the deslagging liquid is transported to a Weiam machine for solid-liquid separation; the liquid after solid-liquid separation is pumped to a hydraulic screen for hydraulic screening; the solid residue after deslagging, solid-liquid separation and hydraulic screening is returned to the hydrolysis acidification equipment.

[0017] According to another aspect of the present invention, a three-phase kitchen water treatment system provided by the present invention comprises: a hydrolysis and acidification device, an ammoniation device, a multi-stage filtration device and an ultrafiltration membrane system connected in sequence through pipelines, wherein the hydrolysis and acidification device is used to receive three-phase water and anaerobic biogas slurry, so that the three-phase water and anaerobic biogas slurry are hydrolyzed and acidified therein; the ammoniation device is used to receive the hydrolysis and acidification solution, so that the hydrolysis and acidification solution is ammonified therein; the multi-stage filtration device comprises a deslagging machine, a solid-liquid separator and a hydraulic screen connected in sequence, and is used to perform deslagging, solid-liquid separation, and hydraulic screening on the ammoniation-treated solution in sequence to obtain a filtrate; the ultrafiltration membrane system is used to pump the filtrate into it and perform ultrafiltration, and has a clear liquid outlet and a concentrated liquid outlet, wherein the clear liquid outlet is connected to the external carbon source inlet of the sewage treatment biochemical system, and the concentrated liquid outlet is connected to the hydrolysis and acidification tank and the inlet of the ultrafiltration membrane system through a pipeline.

[0018] Optionally, it also includes: an anaerobic digestion system for performing anaerobic fermentation on three-phase water to produce biogas; and a biogas slurry tank for storing fermented anaerobic biogas slurry, wherein the biogas slurry tank is connected to the hydrolysis and acidification equipment.

[0019] Optionally, the ultrafiltration membrane system is a tubular ultrafiltration membrane system.

[0020] Optionally, the solid residue outlet of the multi-stage filtering device is connected to a hydrolysis acidification device.

[0021] According to one embodiment of the present invention, anaerobic biogas slurry is added to three-phase water of kitchen and kitchen for hydrolysis and acidification, and then sent to ammoniation equipment for ammoniation after hydrolysis and acidification, so as to make full use of the resources in three-phase water of kitchen and kitchen, increase the VFA content, and convert most of the organic nitrogen into ammonia nitrogen. The slag removal-solid-liquid separation-hydraulic screening coordinated treatment method is adopted to effectively remove the large slag, solid matter and fiber components in the three-phase water after the ammoniation treatment to obtain a filtrate, and the filtrate is pumped into the ultrafiltration membrane system for ultrafiltration, wherein the VFA, COD and organic carbon are retained, the solid suspended matter is completely removed, and most of the nitrogen elements are also intercepted. The clear liquid of the membrane outlet water after ultrafiltration can be used as a carbon source product, and the carbon source is prepared by using three-phase water of kitchen and kitchen. The carbon source product has high VFA content, high ammonia nitrogen / total nitrogen content, and low solid suspended matter content. It is directly put into the sewage treatment biochemical system as an external carbon source, which can reduce the use cost of the external carbon source, reduce the system processing burden, improve the system operation stability, and make up for the imbalance of carbon-nitrogen ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a process flow chart of a three-phase kitchen water treatment method in one embodiment of the present invention.

[0023] Figure 2 It is a process flow chart of a three-phase kitchen water treatment method in one embodiment of the present invention.

[0024] Figure 3 and Figure 4 It is a curve comparison diagram of various indicators obtained in specific embodiments 1-4 of the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The three-phase water described in this application, namely the three-phase water of restaurant kitchen, refers to: the liquid and solid phases after the three-phase oil extractor extracts oil in the restaurant kitchen waste treatment process. Among them, the restaurant kitchen waste treatment process: the restaurant kitchen waste is collected and transported to the treatment plant, and solid-liquid separation is achieved in the receiving hopper. The solid is transported for disposal after large material sorting and fine sorting. The separated fine material enters the slurry heating device, and is sent to the solid-liquid separation after heating to obtain solid residue and filtrate. The filtrate is sent to the sand and scum separator together with the drain water in the receiving hopper to remove heavy sand and light scum. The liquid phase after separation enters the three-phase oil extractor, and the separated crude oil is sold to the outside. The liquid and solid phases after oil separation are the three-phase water of restaurant kitchen.

[0027] The inventors of this application have found that if all the three-phase kitchen water is used for anaerobic fermentation to produce biogas, it will cause a waste of resources, especially carbon sources. The biogas is used for power generation, and part of it is converted into CO in the process. 2 It is directly discharged and not utilized.

[0028] Through the study of three-phase kitchen water, it is found that the C:N of the three-phase water is ≈ 40:1, but its SS and oil content are relatively high. If it is directly used as a carbon source in a sewage treatment biochemical system, such as in the mainstream process MBR (membrane bioreactor) for leachate treatment, excessive SS and oil content will have a serious impact on the system, and even lead to system collapse, substandard effluent quality, and scrapping of membrane components. Table 1 shows the main parameters of the three-phase water in an embodiment.

[0029] Table 1 Main parameters of three-phase water

[0030]

[0031] As shown in Table 1, in this embodiment, the SS in the three-phase water is as high as 40020 mg / L. Directly using it as a carbon source in the sewage treatment biochemical system will inevitably increase the load of the system. In addition, the inventors of the present application also noticed that the total nitrogen content in the three-phase water is too high, and the organic nitrogen content is high, and the excessive organic nitrogen cannot be completely degraded, which ultimately leads to substandard effluent quality. At present, some processes take into account the degradation of organic nitrogen, but they are degraded as much as possible through long-term sewage biochemical treatment, 6 to 7 days, or even extended to more than 30 days; and for some sewage treatment biochemical treatment processes with short treatment cycles in this application, such as a treatment cycle of 8 to 10 hours, there is currently no effective solution that can remove ammonia nitrogen in such a short time.

[0032] Based on this, the present application combines the three-phase kitchen water treatment with the sewage treatment, and utilizes the three-phase kitchen water to prepare a carbon source product which can be used as an additional carbon source for the biochemical treatment of sewage.

[0033] Figure 1The process flow of the three-phase kitchen water treatment method provided in one embodiment of the present application is schematically shown. Figure 1 As shown, the method for treating three-phase kitchen water comprises: collecting three-phase water and sending it to a hydrolysis and acidification tank for hydrolysis and acidification, sending it to an ammoniaization tank for ammoniaization after hydrolysis and acidification, and treating it with a slag remover, a WAM machine, and a hydraulic screen to obtain a filtrate after ammoniaization, and sending the filtrate to an ultrafiltration membrane system for ultrafiltration. The clear liquid of the membrane effluent is the carbon source product, which can be directly used as an external carbon source in the biochemical treatment of sewage treatment.

[0034] This method can make full use of all carbon sources in three-phase water, realize the maximum utilization of carbon source resources in three-phase water, effectively reduce SS and oil content in three-phase water, convert most of organic nitrogen into ammonia nitrogen, and increase VFA content. The prepared carbon source product can be directly used in the sewage treatment biochemical system as an external carbon source. Compared with the three-phase water directly as the carbon source, it can reduce the burden on the biochemical treatment system. The use of three-phase water to prepare carbon source not only saves a lot of carbon source purchase costs for the sewage treatment plant, but also reduces the cost of treating the three-phase water itself.

[0035] Figure 2 The schematic diagram shows a process of a three-phase kitchen water treatment method provided in a preferred embodiment of the present application. In this embodiment, the hydrolysis and acidification of the three-phase water is carried out by adding anaerobic biogas slurry. The anaerobic biogas slurry refers to the biogas slurry obtained by anaerobically fermenting the three-phase water in an anaerobic digestion system to produce biogas. This embodiment makes full use of the resources in the three-phase water, and at the same time makes full use of the anaerobic biogas slurry after the anaerobic digestion of the three-phase water, and performs hydrolysis, acidification and ammoniation treatment to increase the VFA content and the organic nitrogen conversion rate. Figure 2 As shown, the three-phase kitchen water treatment method in this embodiment includes step S10, step S20 and step S30.

[0036] Step S10, collecting part of the three-phase water into the anaerobic digestion system, anaerobic fermentation produces biogas, and the anaerobic biogas slurry after fermentation is stored in the biogas slurry tank; collecting part of the three-phase water into the hydrolysis and acidification tank, adding the anaerobic biogas slurry, hydrolyzing and acidifying; sending the hydrolyzed and acidified three-phase water to the ammoniation tank, ammoniation, and obtaining the ammonified three-phase water.

[0037] By adding anaerobic biogas slurry to the three-phase water for hydrolysis and acidification, on the one hand, the bacterial flora contained in the anaerobic biogas slurry meets the inoculation requirements of hydrolysis acidification and ammoniation; on the other hand, the addition of anaerobic biogas slurry can increase the pH of the three-phase water, providing a favorable environment for the reaction, thereby reducing the addition of alkaline agents such as NaOH, avoiding the harm of chemical agents to the proliferation of microorganisms in the sewage treatment biochemical system, and reducing costs.

[0038] Through hydrolysis-acidification-ammoniation treatment, the VFA content is increased, which can be better utilized by microorganisms in the biochemical system, improving the nitrification-denitrification performance, and at the same time converting most of the organic nitrogen into ammonia nitrogen, solving the problem of excessive organic nitrogen in three-phase water, which can be better removed in the nitrification-denitrification process. In addition, through the hydrolysis-acidification-ammoniation treatment of three-phase water, substances that were originally difficult to remove are degraded into small, fragile, and easy-to-handle particles, making the subsequent treatment easier.

[0039] In addition, in the food waste treatment plant, the amount of food waste water discharged every day is very large. If it only relies on a single treatment method, such as relying solely on "anaerobic digestion treatment", the utilization rate is too low and it cannot be fully utilized as a resource. This embodiment divides the three-phase water into two treatment paths, one part is sent to the anaerobic digestion system for treatment, and the other part is sent to the hydrolysis acidification tank for treatment. The specific distribution ratio is not limited and can be determined according to the demand for external carbon source for sewage treatment; thereby achieving the maximum utilization of the three-phase water resources of food waste.

[0040] In a preferred embodiment, the hydrolysis and acidification is carried out for 3 to 4 days, for example, 3 days, etc. Within this time, the VFA content can reach a peak value, which can maximize the nitrification-denitrification performance of the biochemical system.

[0041] In addition, the hydrolysis and acidification treatment is carried out in a hydrolysis and acidification tank under the following conditions: the pH value is controlled at 6.5-7.0 and the temperature is 30°C-40°C. Through hydrolysis and acidification, the macromolecular insoluble organic matter in the three-phase water is converted into small molecular soluble organic matter, and then into organic acids, which effectively increases the content of VFA.

[0042] In a preferred embodiment, the hydrolyzed acidified three-phase water is sent to an ammoniation tank and ammoniation is performed for 1 to 4 days to obtain ammoniation three-phase water. Preferably, the ammoniation is performed for 1 to 3 days. The inventors of the present application have found that if the ammoniation treatment time exceeds 3 days, the VFA content will decrease, VFA / SCOD will decrease, and SCOD / TN will decrease; in addition, the ammoniation effect has reached the best within 3 days, and increasing the time will waste tank capacity, or the tank volume needs to be increased to meet the treatment requirements.

[0043] In addition, the ammoniation treatment is carried out in the ammoniation tank under the following conditions: pH value is controlled at 6.5-7.0 and temperature is 30℃-40℃. The ammoniation effect is optimal under the above conditions. During the ammoniation process, the ammonifying bacteria brought into the anaerobic biogas slurry convert most of the organic nitrogen into ammonia nitrogen, so that it can be better removed in the nitrification-denitrification process of the biochemical system. In other words, it is possible to obtain water quality that meets the standards in a shorter biochemical treatment cycle.

[0044] In a preferred embodiment, in the hydrolysis and acidification tank, the ratio of three-phase water to anaerobic biogas slurry is: 9: (1-2.5). For example, the ratio of the two is 9: 1, 8: 2, etc. The above ratio can meet the requirements of hydrolysis and acidification and subsequent ammoniation; the inventors also found that: the COD content in the anaerobic biogas slurry is low, and the addition amount should not be too large, so as not to over-dilute the carbon content of the three-phase water and reduce the COD in the three-phase water, which will reduce the carbon-nitrogen ratio. In order to make full use of all carbon sources in the three-phase water, the anaerobic biogas slurry is controlled within the above range.

[0045] In some embodiments of the present invention, considering that the optimal pH for ammoniation treatment is 6.5-7.0, the pH during hydrolysis and acidification treatment is limited to a narrow range of pH 6.5-7.0, thereby satisfying the hydrolysis and acidification treatment and being more conducive to the subsequent ammoniation reaction, thereby avoiding the addition of chemical agents and causing harm to the growth and reproduction of microorganisms in the sewage treatment biochemical system.

[0046] In addition, the hydrolysis acidification and amination of the present invention are carried out in respective tanks, so that both bacteria can work in their most suitable environment, thereby improving the efficiency of hydrolysis acidification and amination, and there is no need to add additional catalysts, and only the above conditions need to be controlled.

[0047] Step S20, the three-phase water after ammoniation is subjected to deslagging, solid-liquid separation, and hydraulic screening in sequence to obtain a filtrate, and the filtrate is sent to an ultrafiltration membrane system for treatment.

[0048] This step can filter out most of the solid matter through slag removal and solid-liquid separation, and then use a hydraulic screen for hydraulic screening. The hydraulic screen is a non-powered design, and relies on waterfalls to filter out a large amount of fine fiber components in the water. The filtrate obtained is beneficial to the subsequent ultrafiltration membrane system, avoiding membrane clogging and increasing the service life of the membrane. In addition, it is also more conducive to the implementation of some membrane-treated wastewater treatment processes.

[0049] In an optional embodiment, a combination of a slag remover, a WAM machine and a hydraulic screen is used. Specifically, it includes:

[0050] 1) The three-phase water after hydrolysis-acidification-ammoniation is transported to the slag remover through a pipeline to remove large slag from the kitchen waste, such as bones. The solid slag can be partially returned to the hydrolysis and acidification tank or transported out for disposal.

[0051] 2) After slag removal, the three-phase water is transported to the WAM machine through a pipeline to remove most of the solid matter. The three-phase water after slag removal enters the screen box from the feed inlet, and the shaftless screw in the screen box separates, lifts and compresses the solid waste raw materials from the water. The filtered liquid enters the buffer box below the WAM machine from the liquid outlet of the WAM machine for storage. The volume of the buffer box is about 2 cubic meters. The solid slag can be partially returned to the hydrolysis acidification tank or transported for disposal.

[0052] 3) The filtered liquid in the buffer box after being treated by the WAM machine is pumped into the hydraulic screen to remove the fiber components in the three-phase water. There is a water storage tank above the hydraulic screen, and the water in it is evenly distributed to the arc screen through the overflow weir. Since the gap on the surface of the screen is small and smooth, and the gap on the back is large, the water body continuously washes the screen, which plays a role in cleaning the screen and is not easy to block. The solid matter is trapped on the mesh surface, and the water passing through the screen flows out from the gap of the screen plate and enters the next processing section; at the same time, under the action of gravity, the intercepted solid matter gathers and rolls along the surface of the screen to the spiral system, and the filtered liquid enters the buffer barrel of the hydraulic screen outlet, and the volume of the buffer barrel is about 5 cubic meters. The solid residue can be partially returned to the hydrolysis acidification tank, or it can be transported for disposal. After the slag remover and the WAM machine filter out most of the solids, a large amount of fine fiber components in the water are further filtered out by using a hydraulic screen to obtain a filtrate. The filtrate will not cause the membrane of the ultrafiltration membrane system to be blocked, thereby improving the service life of the ultrafiltration membrane system.

[0053] Step S30, the filtrate is pumped into the ultrafiltration membrane system for ultrafiltration, and the clear liquid out of the membrane is the carbon source product, which can be used as an external carbon source in the sewage treatment biochemical system, and the concentrated liquid is returned to the hydrolysis acidification equipment for recycling.

[0054] After hydrolysis, acidification and amination treatment, most of the organic nitrogen in the three-phase water is converted into ammonia nitrogen. The VFA, COD and organic carbon in the filtrate are retained by filtering and ultrafiltration membrane treatment, and all suspended solids are removed, and most of the nitrogen elements are also intercepted. The clear water from the membrane can be directly put into the sewage treatment biochemical system as an external carbon source, which can reduce the cost of using the external carbon source while reducing the system processing burden, improve the system operation stability, and make up for the imbalance of the carbon-nitrogen ratio.

[0055] The inventor of this application has considered the particularity of three-phase kitchen water and the requirements of the biochemical treatment process for sewage treatment. This application uses an ultrafiltration membrane system to further filter the filtrate, which has at least the following beneficial effects: 1) The clear liquid obtained by the ultrafiltration membrane system is sent to the sewage treatment biochemical system, which is more conducive to the biochemical treatment, can reduce the system operation burden, and improve stability. In addition, it can avoid the membrane clogging problem in the sewage treatment biochemical system treated by the membrane. For example, if the clear liquid is used as an external carbon source for the MBR treatment of landfill leachate, it can effectively avoid the MBR membrane clogging problem and improve the treatment efficiency. 2) SS can be further reduced to 0, which is more conducive to the stable operation of the sewage treatment biochemical system and prolongs its service life. 3) In addition, the ultrafiltration membrane system can further intercept particulate organic nitrogen and reduce the organic nitrogen content in the membrane effluent clear liquid. 4) The ultrafiltration membrane system is filtered, and the membrane equipment has a high degree of integration, a small footprint, and is easy to operate.

[0056] The reflux process is used to return the microorganisms in the concentrated solution to the hydrolysis acidification tank, so that the concentration of microorganisms is improved. Some organic matter in the reflux wastewater that has not been decomposed in time can also be further decomposed after returning to the front tank, further reducing the disposal cost. In addition, the concentrated solution can also be returned to the ultrafiltration membrane system for recycling. Preferably, a tubular ultrafiltration membrane system is used for ultrafiltration.

[0057] In addition, the sewage treatment biochemical system, for example, can be a landfill leachate MBR system, a sewage treatment biochemical system with a short treatment cycle, and the clear liquid obtained in the present application, i.e., the carbon source product, has a more prominent beneficial effect, especially for a sewage treatment biochemical system with a treatment cycle of 8 to 10 hours, because in the 8 to 10-hour sewage treatment cycle, it is completely impossible to convert all of it into ammonia nitrogen, and then it is impossible to completely remove it, resulting in substandard water quality and poor system operation stability. In the embodiments of the present application, the organic nitrogen in the clear liquid has been converted into ammonia nitrogen, which can be completely removed during the nitrification-denitrification process of 8-10 hours of sewage treatment.

[0058] According to the three-phase kitchen water treatment method provided by the preferred embodiment of the present invention, the final ultrafiltration clear liquid has ammonia nitrogen / total nitrogen of 65% to 75%, VFA increased by 25g / L to 30g / L, and VFA / SCOD of 40% to 50%. COD is usually 60000mg / L to 80000mg / L. C / N is 40 to 50. In addition, in most embodiments, SS can be completely removed and reduced to 0, and all embodiments are reduced to below 0.01.

[0059] The three-phase kitchen water treatment system provided in one embodiment of the present application comprises: a hydrolysis and acidification device, an ammoniation device, a multi-stage filtration device and an ultrafiltration membrane system connected in sequence through pipelines. The hydrolysis and acidification device is used to receive three-phase water and anaerobic biogas slurry, so that the three-phase water and anaerobic biogas slurry are hydrolyzed and acidified therein. The ammoniation device is used to receive the hydrolysis and acidification solution, so that the hydrolysis and acidification solution is ammonified therein. The multi-stage filtration device comprises a deslagging machine, a solid-liquid separator and a hydraulic screen connected in sequence, which are used to perform deslagging, solid-liquid separation, and hydraulic screening on the ammoniation-treated solution in sequence to obtain a filtrate; the solid residue outlet is connected to the hydrolysis and acidification device. The ultrafiltration membrane system is used to pump the filtrate into it and perform ultrafiltration. The ultrafiltration membrane system can be, for example, a tubular ultrafiltration membrane system, having a clear liquid outlet and a concentrated liquid outlet, wherein the clear liquid outlet is connected to the external carbon source inlet of the sewage treatment biochemical system, and the concentrated liquid outlet is connected to the hydrolysis and acidification tank and the inlet of the ultrafiltration membrane system through a pipeline.

[0060] In a preferred embodiment, it also includes: an anaerobic digestion system for anaerobic fermentation of three-phase water to produce biogas; and a biogas slurry tank for storing fermented anaerobic biogas slurry, wherein the biogas slurry tank is connected to the hydrolysis and acidification equipment, so that the anaerobic biogas slurry is added to the three-phase water for hydrolysis and acidification treatment.

[0061] The present application is described in more detail below with reference to specific embodiments:

[0062] Examples 1-4

[0063] First, the three-phase water anaerobic hydrolysis produces acid and ammoniation reaction

[0064] Collect the three-phase water into the hydrolysis acidification tank, control the pH value at 6.5-7.0, adjust the temperature to 35°C, add anaerobic biogas slurry into the hydrolysis acidification tank, the ratio of three-phase water to anaerobic biogas slurry is 9:1, and the hydrolysis time is 3 days. On the 4th day, the three-phase water in the hydrolysis acidification tank is transported to the ammoniation tank through a pipeline, the pH value in the ammoniation tank is controlled at 6.5-7.0, the temperature is controlled at 35°C, and the ammoniation treatment is carried out for 4 days.

[0065] Secondly, three-phase water deep treatment

[0066] First, the three-phase water after ammoniating is removed by a deslagging machine-WAM machine-hydraulic screen in turn for deslagging, separation, hydraulic screening and filtration to obtain the filtrate; then the filtrate is pumped into the ultrafiltration membrane system for ultrafiltration, and the membrane effluent clear liquid is the carbon source product, which is used as an external carbon source in the landfill leachate MBR system, and the concentrated liquid is returned to the hydrolysis acidification tank and the ultrafiltration membrane system for recycling; part of the solid residue is returned to the hydrolysis acidification tank, and part is transported out for disposal.

[0067] Among them, Examples 1-4 correspond to ammoniation treatment for 1 day, ammoniation treatment for 2 days, ammoniation treatment for 3 days, and ammoniation treatment for 4 days, respectively, and the other steps are the same.

[0068] Taking Example 3, i.e. the three-phase water obtained by ammoniation treatment for 3 days, as an example, the comparison of various data before and after deep treatment is shown in Table 2 below: Among them, the three-phase water before deep treatment refers to the three-phase water after ammoniation, which has not been filtered and contains many impurities, and many indicators are much higher than the clear liquid after filtration.

[0069] Table 2 Comparison of data before and after deep treatment of three-phase water

[0070]

[0071]

[0072] It can be seen from Table 2 that by deeply treating the three-phase water after ammoniation, VFA, COD, and organic carbon are retained, all suspended solids SS are removed, and most of the nitrogen elements are intercepted. The ultrafiltration clear liquid can be directly put into the sewage treatment biochemical system as an external carbon source.

[0073] In addition, the various indicators obtained in specific examples 1-4 were tested (after filtering), and curve comparison diagrams were drawn, as shown in the following figure. Figure 3 and Figure 4 As shown. Figure 3 It can be seen that the VFA content increased significantly, ammonia nitrogen increased after 4 days and before 7 days, and the total nitrogen remained within a certain range. It can be seen that most of the organic nitrogen was converted into ammonia nitrogen. After 7 days, the VFA decreased rapidly. Figure 4 It can be seen that ammonia nitrogen / total nitrogen increased rapidly after 4 days, reached the highest point after 5 days and before 7 days and remained above 60%. At this time, SCOD / TN and VFA / SCOD also remained within a certain range.

[0074] Compared with the prior art, some embodiments of the present application also have the following advantages:

[0075] 1) The carbon source resources in the three-phase water of the kitchen are fully utilized. By hydrolysis, acidification and ammoniation treatment and optimizing its reaction conditions, the problem of excessive organic nitrogen in the three-phase water is solved, so that most of the organic nitrogen is converted into ammonia nitrogen, which can be better removed in the nitrification-denitrification process. At the same time, the VFA content is increased, which can be better utilized by microorganisms in the sewage biochemical system, thereby improving the nitrification-denitrification performance.

[0076] 2) The three-phase water is treated by hydrolysis, acidification and amination. The substances that were originally difficult to remove are degraded into small, fragile and easy-to-handle particles, making the subsequent treatment easier.

[0077] 3) Most of the solid matter in the three-phase water of food waste can be filtered out by using a slag remover and a WAM machine; the hydraulic screen is a non-powered design, and relies on the waterfall to filter out a large amount of fine fiber components in the water; through the coordinated use of the slag remover-WAM machine-hydraulic screen, the filtrate is obtained, and the filtrate is treated with an ultrafiltration membrane, which solves the problem of easy clogging of the ultrafiltration membrane when the three-phase water passes through the ultrafiltration membrane, and at the same time improves the service life of the membrane.

[0078] 4) The filtrate after slag removal, separation and hydraulic screening is ultrafiltered, VFA, COD and organic carbon are retained, all suspended solids are removed, and most of the nitrogen elements are intercepted, which can be directly added to the sewage treatment biochemical system as an external carbon source, reducing the use of external carbon sources in the system. The membrane equipment has a high degree of integration, small footprint and easy operation.

[0079] 5) Physical multi-stage filtration is used to treat the three-phase water of food waste as a carbon source without the addition of chemicals, thus avoiding the harm of chemical agents to the growth and reproduction of microorganisms in the sewage treatment biochemical system.

[0080] 6) Through the reflux process, the microorganisms in the three-phase water are returned to the hydrolysis acidification tank, the microbial concentration is improved, and some organic matter in the reflux wastewater that has not had time to decompose can be further decomposed after returning to the front tank, further reducing the disposal cost.

[0081] 7) A carbon source product is prepared by making full use of the three-phase food waste water, and can be directly used as an external carbon source in the sewage treatment biochemical system, especially in the sewage treatment biochemical system with a treatment cycle of 8 to 10 hours. It has a more outstanding contribution, not only saving a lot of carbon source costs for the sewage treatment plant, but also reducing the system processing burden, improving the system operation stability, compensating for the imbalance of carbon-nitrogen ratio, and also reducing the cost of treating food wastewater itself.

[0082] 8) Taking into full consideration the characteristics of anaerobic biogas slurry, the anaerobic biogas slurry is added to the three-phase water for hydrolysis and acidification, and the addition ratio is optimized. On the one hand, the bacterial flora contained in the anaerobic biogas slurry meets the inoculation requirements of hydrolysis, acidification and ammoniation; on the other hand, the addition of anaerobic biogas slurry can increase the pH of the three-phase water, provide a favorable environment for the reaction, reduce the addition of pH chemical agents, and avoid the harm of chemical agents to the proliferation of microorganisms in the sewage treatment biochemical system.

[0083] The description of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for particular uses.

Claims

1. A method for treating three-phase kitchen water, characterized in that: include: Collect three-phase kitchen water and send it to the anaerobic digestion system for anaerobic fermentation to produce biogas, and store the fermented anaerobic biogas in the biogas tank; Collecting three-phase kitchen water and sending it to a hydrolysis and acidification device, adding the anaerobic biogas slurry, hydrolyzing and acidifying for 3 to 4 days, controlling the pH value to 6.5 to 7.0, and the temperature to 30° C. to 40° C.; sending the hydrolyzed and acidified three-phase water to an ammoniation device, ammoniating for 1 to 3 days, controlling the pH value to 6.5 to 7.0, and the temperature to 30° C. to obtain ammoniated three-phase water; The three-phase water after ammoniation is subjected to deslagging, solid-liquid separation and hydraulic screening in sequence to obtain a filtrate; the filtrate is pumped into an ultrafiltration membrane system for ultrafiltration, and the clear liquid out of the membrane is the carbon source product, which is used as an external carbon source in a wastewater treatment biochemical system, and the concentrated liquid is refluxed to the hydrolysis acidification equipment.

2. The method for treating kitchen three-phase water according to claim 1, characterized in that: In the hydrolysis and acidification equipment, the ratio of three-phase kitchen water to anaerobic biogas slurry is: 9: (1-2.5).

3. The method for treating kitchen three-phase water according to claim 1, characterized in that: The steps of sequentially performing slag removal, solid-liquid separation, and hydraulic screening on the three-phase water after ammoniation include: The ammoniated solution is deslagging by a deslagging machine; the deslagging liquid is transported to a Weiam machine for solid-liquid separation; the liquid after solid-liquid separation is pumped to a hydraulic screen for hydraulic screening; the solid residue after deslagging, solid-liquid separation and hydraulic screening is returned to the hydrolysis acidification equipment.

4. A three-phase kitchen water treatment system used in the three-phase kitchen water treatment method according to any one of claims 1 to 3, characterized in that: include: Anaerobic digestion system, hydrolysis acidification equipment, ammoniation equipment, multi-stage filtration device and ultrafiltration membrane system connected in sequence through pipelines, wherein: The anaerobic digestion system is used to perform anaerobic fermentation on three-phase water to produce biogas; it includes a biogas slurry tank for storing fermented anaerobic biogas slurry, and the biogas slurry tank is connected to the hydrolysis and acidification equipment; The hydrolysis and acidification equipment is used to receive the three-phase water and the anaerobic biogas slurry, so that the three-phase water and the anaerobic biogas slurry are hydrolyzed and acidified therein; The ammoniaizing device is used to receive the hydrolyzed and acidified solution and to ammoniaize the hydrolyzed and acidified solution therein; The multi-stage filtering device comprises a deslagging machine, a solid-liquid separator and a hydraulic screen connected in sequence, and is used to perform deslagging, solid-liquid separation and hydraulic screening on the solution after the ammoniation treatment in sequence to obtain a filtrate. The ultrafiltration membrane system is used for pumping filtrate into it and performing ultrafiltration, and has a clear liquid outlet and a concentrated liquid outlet, wherein the clear liquid outlet is connected to the external carbon source inlet of the sewage treatment biochemical system, and the concentrated liquid outlet is connected to the hydrolysis acidification tank and the inlet of the ultrafiltration membrane system through a pipeline.

5. The three-phase kitchen water treatment system according to claim 4, characterized in that: The ultrafiltration membrane system is a tubular ultrafiltration membrane system; The solid residue outlet of the multi-stage filtering device is connected to the hydrolysis acidification equipment.

Images