Hermetia illucens biological decrement and carbon source optimization leachate treatment and recovery system and method

Abstract

The present invention relates to the technical field of water pollution control and treatment, and discloses a hermetia illucens biological decrement and carbon source optimization leachate treatment and recovery system and method, the system comprises: a pretreatment module for performing pH adjustment, impurity removal and microbial pretreatment on an initial leachate; the hermetia illucens biological reduction module is used for treating the pretreatment percolate through hermetia illucens larvae and adding a specific auxiliary matrix to realize reduction of the volume of the percolate; the leachate concentration module is used for concentrating and collecting the residual leachate through a membrane separation technology; the carbon source optimization module is used for mixing the concentrated leachate with an external carbon source to prepare a low-COD equivalent functional solution so as to obtain a mixed carbon source; and the resource recovery module is used for performing graded extraction on the hermetia illucens larvae participating in the pretreatment penetrating fluid treatment in the hermetia illucens biological reduction module to obtain protein, chitin and organic fertilizer. According to the method, efficient reduction of the leachate, removal of pollutants, recycling of organic matters and high-value utilization of hermetia illucens products can be realized.

Description

Technical Field

[0001] The present invention relates to the technical fields of water pollution control and treatment, liquid recycling and utilization, and the fields of environmental engineering and resource recycling. Specifically, it relates to a leachate treatment and recovery system and method for black soldier fly biological reduction and carbon source optimization, which is applicable to the treatment and resource utilization of high-concentration and high-salinity leachate generated from food waste, garbage transfer stations, etc. Background Art

[0002] During the garbage treatment process, the generated leachate exhibits characteristics such as high chemical oxygen demand (COD), high salinity, high ammonia nitrogen, and complex composition, making it one of the important sources of environmental pollution. Currently, most leachate treatments adopt biochemical methods and physicochemical methods, such as anaerobic-aerobic biochemical treatment, membrane separation technology, and evaporation crystallization. However, these treatment methods have many drawbacks: traditional biochemical treatment has poor adaptability to high-salt and high-ammonia-nitrogen leachate, which will seriously inhibit the activity of microorganisms; membrane separation technology faces problems such as serious membrane fouling, high energy consumption, and difficult treatment of concentrated liquid; the evaporation crystallization method not only consumes a large amount of energy but also has a high operating cost. In addition, the existing technical routes generally lack the concept of resource recycling and utilization, and cannot realize the resource utilization of organic matter in leachate.

[0003] With the increasingly strict environmental protection standards and the wide spread of the concept of circular economy, it is urgent to develop a technology that can not only achieve the reduction treatment of leachate but also recover valuable resources therein. As an efficient organic waste conversion organism, the black soldier fly has been applied in the field of food waste treatment, but the special treatment technology for leachate characteristics has not been systematically developed. Moreover, if the high-concentration organic matter in leachate can be reasonably utilized as a carbon source, the resource utilization efficiency can be greatly improved. Unfortunately, there are extremely few systematic solutions for optimizing the utilization of leachate carbon source characteristics in the existing technology. Summary of the Invention

[0004] The present invention aims to provide a leachate treatment and recovery system and method for black soldier fly biological reduction and carbon source optimization, so as to achieve the efficient reduction of leachate, the resource utilization of organic matter, and the reduction of salinity, improve the ability of water pollution control and treatment, and recycle the polluted liquid; at the same time, it can also effectively treat and diversely recycle the products of black soldier fly and convert them into high-value products, with significant environmental and economic benefits.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] Solution 1: A leachate treatment and recovery system for black soldier fly biological reduction and carbon source optimization, comprising:

[0007] A pretreatment module for adjusting the pH, removing impurities, and performing microbial pretreatment on the initial leachate to reduce the toxicity of the leachate and improve its biodegradability, thereby obtaining pretreated leachate;

[0008] A black soldier fly biological reduction module that processes the pretreated leachate with black soldier fly larvae and adds a specific auxiliary substrate to reduce the volume of the leachate, thereby obtaining residual leachate;

[0009] A leachate concentration module that concentrates and collects the residual leachate through membrane separation technology to obtain concentrated leachate;

[0010] A carbon source optimization module that mixes the concentrated leachate with an external carbon source to prepare a functional solution with a low COD equivalent, while reducing the salinity and improving the biodegradability to obtain a mixed carbon source;

[0011] A resource recovery module that fractionally extracts the black soldier fly larvae involved in the pretreatment of the leachate in the black soldier fly biological reduction module to obtain protein, chitin, and organic fertilizer.

[0012] Beneficial effects: Through the coordinated cooperation of multiple functional modules, the system forms a complete leachate treatment technology chain, achieving the synergistic effect of pollutant reduction and resource utilization. It can efficiently treat leachate, reduce its toxicity and salinity, simultaneously recycle the organic matter in the leachate, and also highly value-added recycle the products of black soldier flies, with significant environmental and economic benefits; the intelligent monitoring module monitors and adjusts in real time to ensure the stable and efficient operation of the system.

[0013] Preferably, the pretreatment module includes a pH adjustment unit, a precipitation separation unit, and a microbial pretreatment unit; the pH adjustment unit uses an automatic dosing system to adjust the pH of the leachate to the range of 6.5 - 7.5; the precipitation separation unit removes large particle suspended solids and heavy metals through coagulation precipitation; the microbial pretreatment unit inoculates a salt-tolerant composite microbial community and pretreats it at 28°C for 24 - 48 hours to increase the BOD5 / COD of the leachate.

[0014] Beneficial effects: Adjusting the pH of the leachate to an appropriate range by the pH adjustment unit is beneficial for subsequent treatment; the precipitation separation unit removes large particle suspended solids and heavy metals, reducing the impact on subsequent treatment units; the microbial pretreatment unit uses a salt-tolerant composite microbial community to reduce the toxicity of the leachate, increase the BOD5 / COD, enhance the biodegradability of the leachate, and create good conditions for the black soldier fly biological reduction module.

[0015] Preferably, the black soldier fly biological reduction module adopts a multi-stage temperature gradient design, including a primary treatment unit, an intermediate treatment unit, and a high-temperature treatment unit; the temperature of the primary treatment unit is controlled at 28-32 °C, the temperature of the intermediate treatment unit is 33-37 °C, and the temperature of the high-temperature treatment unit is 38-42 °C; a specific auxiliary substrate is prepared according to the ratio of straw, wood chips, and fruit and vegetable waste of 3:2:5, the C / N ratio is controlled at (20-25):1, and the mass ratio of leachate to the auxiliary substrate is 3:1.

[0016] Beneficial effects: The multi-stage temperature gradient design provides suitable temperatures for different growth stages of black soldier fly larvae, promoting their rapid growth and the treatment of leachate; the auxiliary substrate with a specific ratio and C / N ratio, combined with an appropriate mass ratio of leachate to the auxiliary substrate, optimizes the treatment environment, improves the reduction effect of leachate, significantly reduces the volume of leachate, and at the same time increases the yield and quality of black soldier fly larvae.

[0017] Preferably, the leachate concentration module includes a microfiltration device, an ultrafiltration device, and a storage tank; the microfiltration aperture of the microfiltration device is 0.45 μm, which is used to remove solid impurities in the leachate; the ultrafiltration device uses a hollow fiber membrane with a molecular weight cut-off value of 10,000 Da, which is used to remove macromolecular organic matter and colloidal substances.

[0018] Beneficial effects: The combination of the microfiltration device and the ultrafiltration device can effectively remove solid impurities, macromolecular organic matter, and colloidal substances in the leachate, increase the COD equivalent of the concentrated leachate, improve the concentration multiple, provide a high-concentration organic solution for the carbon source optimization module, and increase the utilization value of the subsequent carbon source.

[0019] Preferably, the carbon source optimization module includes a carbon source preparation unit, a mixing reaction unit, and a performance testing unit; the carbon source preparation unit mixes the concentrated leachate with molasses and food processing waste liquid according to the ratio of 1:3:6, and adds a trace element regulator; the mixing reaction unit stirs and reacts at 30 °C for 4-6 hours; the performance testing unit monitors the COD, BOD5, pH, and salinity indicators of the prepared solution in real time.

[0020] Beneficial effects: The carbon source preparation unit mixes the concentrated leachate with an external carbon source in a specific ratio and adds a trace element regulator to improve the solution composition; the mixing reaction unit promotes the mutual solubility of organic components and improves the solution stability; the performance testing unit monitors the key indicators in real time to ensure that the prepared solution with a low COD equivalent meets the requirements, reduces the salinity, improves the biodegradability, is suitable for the addition of carbon sources in subsequent biological treatment processes, and improves the carbon source utilization efficiency and treatment effect.

[0021] Preferably, the resource recovery module includes a separation device, a protein extraction unit, a chitin extraction unit, and a fertilizer preparation unit; the separation device uses a vibrating screen to separate black soldier fly larvae from residual materials; the protein extraction unit extracts proteins using an alkaline protein dissolution-acidic isoelectric point precipitation process; the chitin extraction unit extracts chitin using a mild alkali extraction technique; the fertilizer preparation unit mixes the extracted residue with the residual materials and adds beneficial microorganisms for fermentation to prepare organic fertilizers.

[0022] Beneficial effects: Through different extraction and preparation processes, the resource recovery module performs hierarchical extraction on black soldier fly larvae, realizes the high-value utilization of resources in the whole chain, obtains high-quality proteins, chitin, and organic fertilizers with comprehensive nutrients, improves the economic benefits of the system, and reduces waste emissions at the same time, having good environmental benefits.

[0023] Preferably, it further includes an intelligent monitoring module for real-time monitoring of the operating parameters of each module, including temperature, humidity, pH value, COD concentration, and the growth status of black soldier fly larvae, and automatically adjusting the target range of the system operating parameters through an adaptive algorithm.

[0024] Beneficial effects: The intelligent monitoring module monitors multiple parameters in real time, timely grasps the operating conditions of the system, automatically adjusts parameters through an adaptive algorithm, ensures the stable and efficient operation of the system, reduces labor costs and operation risks, and improves the processing efficiency and economic benefits.

[0025] Solution 2: A method for treating and recovering leachate with black soldier fly bioreduction and carbon source optimization, using the aforementioned leachate treatment and recovery system with black soldier fly bioreduction and carbon source optimization, includes the following steps:

[0026] Step 1, use the pretreatment module to adjust the pH, remove impurities, and perform microbial pretreatment on the initial leachate to obtain pretreated leachate;

[0027] Step 2, send the pretreated leachate into the black soldier fly bioreduction module, and through the treatment of black soldier fly larvae and specific auxiliary substrates, achieve volume reduction of the leachate to obtain the remaining leachate;

[0028] Step 3, send the remaining leachate treated by the black soldier fly bioreduction module into the leachate concentration module, and concentrate it through membrane separation technology to obtain concentrated leachate;

[0029] Step 4, send the concentrated leachate into the carbon source optimization module, mix it with an external carbon source to prepare a functional solution with a low COD equivalent to obtain a mixed carbon source;

[0030] Step 5, perform hierarchical extraction on black soldier fly larvae, and obtain proteins, chitin, and organic fertilizers through the resource recovery module.

[0031] Beneficial effects: Based on the functions of each module of the system, a complete treatment process is formed, achieving efficient reduction of leachate, resource utilization of organic matter, and reduction of salinity. At the same time, the products of black soldier fly are recycled in a diversified manner, giving full play to the advantages of the system. Compared with traditional treatment methods, the treatment efficiency is significantly improved, the salinity and toxic substances are significantly reduced, the degree of resource utilization is high, the economy is remarkable, and the environmental friendliness is good.

[0032] Preferably, in the microbial pretreatment step of step one, the salt-tolerant composite bacteria are inoculated and pretreated at 28 °C for 24 - 48 hours, and the BOD5 / COD is increased from the initial 0.1 - 0.2 to 0.25 - 0.35.

[0033] Beneficial effects: Through specific microbial pretreatment conditions, the BOD5 / COD of the leachate is effectively increased, and the biodegradability of the leachate is enhanced, laying a good foundation for subsequent treatment steps such as biological reduction of black soldier fly and carbon source optimization, which is beneficial to improving the efficiency and effect of the entire treatment system.

[0034] Preferably, in the biological reduction step of black soldier fly in step two, during the treatment of the pretreated leachate, 15 - 25% of the leachate is accepted by the black soldier fly larvae themselves, 60 - 75% of the leachate is removed by evaporation through temperature gradient control, and the remaining leachate is transferred to the concentration module.

[0035] Beneficial effects: The different treatment routes and proportions of the leachate in the biological reduction process of black soldier fly are clarified. Through the acceptance of black soldier fly larvae and evaporation by temperature gradient, etc., efficient reduction of the leachate is achieved, the treatment load of the subsequent concentration module is reduced, and the treatment efficiency and economy of the entire system are improved.

[0036] Preferably, in the carbon source optimization step of step four, the COD of the prepared low-COD equivalent solution is 5000 - 10000 mg / L, the salinity is reduced to less than 0.5%, and the BOD5 / COD is increased to more than 0.4.

[0037] Beneficial effects: The key indicators of the solution after carbon source optimization are specified, ensuring that the prepared functional carbon source solution is suitable for subsequent biological treatment processes, improving the carbon source utilization efficiency, reducing the treatment cost, effectively reducing the salinity at the same time, reducing the inhibition of microorganisms in the subsequent treatment process, and improving the effect and stability of the entire treatment system.

[0038] The advantages of this solution are:

[0039] Existing leachate treatment technologies have problems such as poor adaptability, high energy consumption, and lack of resource recovery. Through the coordination and cooperation of multiple modules, the present invention cleverly uses black soldier fly as a waste liquid treatment tool and at the same time becomes a product to be recycled, realizing efficient treatment and resource recovery:

[0040] 1. High efficiency in treatment: The volume reduction rate of leachate reaches 80 - 90%, which is significantly improved compared with traditional technologies. Through microbial pretreatment and temperature gradient regulation, etc., it can effectively deal with high-salt and high-ammonia-nitrogen leachate, reduce the salinity to below 0.5%, and the removal rate of toxic substances exceeds 95%.

[0041] 2. High resource utilization: It converts the organic matter in leachate into carbon sources, and extracts high-value products such as proteins and chitin from black soldier fly larvae in a hierarchical manner. The residue is made into organic fertilizers, realizing the whole-chain resource utilization.

[0042] 3. Economical and environmentally friendly: The operating cost is 40% lower than that of traditional membrane separation technology. The system has nearly zero emissions, low energy consumption, and a small carbon footprint, combining economic and environmental benefits.

[0043] 4. Technical integration and innovation: It breakthroughly integrates technologies such as pretreatment, black soldier fly biotransformation, and carbon source optimization to form a complete technical chain, rather than simply piecing together existing technologies. It is a brand-new treatment idea.

[0044] 5. Optimization of parameters and conditions: The parameters and conditions of each treatment link are accurately set, such as the strain combination, temperature, and time of microbial pretreatment, and the temperature gradient and auxiliary matrix ratio of black soldier fly treatment. The optimization of these parameters requires a large number of experimental explorations and is not a conventional means easily thought of by those skilled in the art. Brief Description of the Drawings

[0045] Figure 1 It is a logic block diagram of the system of the present invention.

[0046] Figure 2 It is a flow chart of the method of the present invention. Detailed Description of the Specific Embodiment

[0047] The following is a further detailed description through specific embodiments:

[0048] The reference numerals in the accompanying drawings of the specification include: pretreatment module 1, black soldier fly biological reduction module 2, leachate concentration module 3, carbon source optimization module 4, resource recovery module 5, and console 6.

[0049] The embodiment is basically as shown in the Figure 1 accompanying drawings: An integrated system for leachate treatment and resource recovery based on black soldier fly biological reduction and carbon source optimization technology, including console 6 and the following respectively connected to console 6:

[0050] Pretreatment module 1, used for pH adjustment, impurity removal, and microbial pretreatment of leachate to reduce the toxicity of leachate and improve its biodegradability;

[0051] The black soldier fly biological reduction module 2, connected to the pretreatment module 1, is used to treat leachate with black soldier fly larvae, add an auxiliary substrate to reduce the volume of leachate by 80 - 90%, and the remaining 10 - 20% of the leachate retains a high COD equivalent;

[0052] The leachate concentration module 3, connected to the black soldier fly biological reduction module 2, is used to collect the remaining leachate and concentrate and store it through membrane separation technology;

[0053] The carbon source optimization module 4, connected to the leachate concentration module 3, is used to mix the remaining leachate with an external high COD equivalent carbon source to prepare a low COD equivalent solution, while reducing the salinity of the solution and increasing the biodegradability index to obtain a new mixed carbon source;

[0054] The resource recovery module 5 is used to collect the black soldier fly larva products after being treated by the black soldier fly biological reduction module 2 and convert them into protein, chitin, and organic fertilizer through a fractional extraction process;

[0055] The intelligent monitoring module is used to monitor the operating parameters of each module in real time, including temperature, humidity, pH value, COD concentration, and the growth status of black soldier fly larvae, and automatically adjust the system operating parameters through an adaptive algorithm.

[0056] The console 6, as an existing technology, is connected to each module of the system and mainly undertakes the overall management function of the system operation. It is connected to the pretreatment module 1, the black soldier fly biological reduction module 2, the leachate concentration module 3, the carbon source optimization module 4, the resource recovery module 5, and the intelligent monitoring module through data transmission lines, can receive the operating parameter information of each module in real time, and issue control commands to each module according to preset programs or operator instructions. For example, when the intelligent monitoring module monitors that the temperature of the black soldier fly biological reduction module 2 is abnormal, the console 6 can respond quickly and adjust the temperature control equipment; at the same time, the operator can also intuitively view the overall operating status of the system through the human - machine interaction interface of the console 6, manually adjust the parameters of each module, and achieve convenient control and management of the entire leachate treatment and resource recovery integrated system.

[0057] Among them, the pretreatment module 1 includes a pH adjustment unit, a precipitation separation unit, and a microbial pretreatment unit. A salt - tolerant composite bacterial group is added to the microbial pretreatment unit to reduce the toxicity of organic matter in the leachate.

[0058] In the black soldier fly biological reduction module 2, the auxiliary substrate includes straw, wood chips, fruit and vegetable waste, or a combination thereof, and is configured according to a specific C / N ratio. During the leachate treatment process, the black soldier fly larvae themselves accept 15 - 25% of the leachate, and 60 - 75% of the leachate is removed by evaporation through temperature gradient control.

[0059] The black soldier fly biological reduction module 2 includes multiple temperature gradient treatment units. The temperature of the initial treatment unit is 28 - 32 °C, and the temperature of the subsequent treatment units is 38 - 42 °C. The COD equivalent of the leachate is concentrated 4 - 5 times in the remaining leachate.

[0060] The leachate concentration module 3 includes a microfiltration device, an ultrafiltration device, and a storage tank. The microfiltration device and the ultrafiltration device are configured in series to remove solid impurities and macromolecular organic matter in the leachate. The storage tank is used to temporarily store the concentrated leachate.

[0061] In the carbon source optimization module 4, the external high - COD equivalent carbon source includes molasses, sodium acetate, food processing waste liquid, or a combination thereof, and a trace element regulator is added. The COD equivalent of the formulated low - COD equivalent solution is 5000 - 10000 mg / L, the salinity is reduced to less than 0.5%, and the biodegradability index (BOD5 / COD) is increased to more than 0.4.

[0062] The resource recovery module 5 includes a separation device, a protein extraction unit, a chitin extraction unit, and a fertilizer preparation unit. The separation device is used to separate black soldier fly larvae from the residual materials. The protein extraction unit and the chitin extraction unit are used to extract high - value products from black soldier fly larvae. The fertilizer preparation unit is used to ferment the extracted residue and the residual materials to prepare organic fertilizer.

[0063] As Figure 2 shown, when using the system of the present invention for leachate treatment and recovery, the following steps are included:

[0064] Step 1: Use the pretreatment module 1 to adjust the pH, remove impurities, and perform microbial pretreatment on the initial leachate to obtain pretreated leachate.

[0065] Step 2: Feed the pretreated leachate into the black soldier fly biological reduction module 2, and through the treatment of black soldier fly larvae and a specific auxiliary substrate, achieve volume reduction of the leachate to obtain the remaining leachate.

[0066] Step 3: Feed the remaining leachate treated by the black soldier fly biological reduction module 2 into the leachate concentration module 3, and concentrate it through membrane separation technology to obtain concentrated leachate.

[0067] Step 4: Feed the concentrated leachate into the carbon source optimization module 4, and mix it with an external carbon source to formulate a low - COD equivalent functional solution to obtain a mixed carbon source.

[0068] Step 5: Perform fractional extraction on the black soldier fly larvae, and obtain protein, chitin, and organic fertilizer through the resource recovery module 5.

[0069] The innovation points of the present invention include:

[0070] (1) Multi - level collaborative treatment technology: Innovatively combine pretreatment, black soldier fly biotransformation and carbon source optimization technology to form a complete technical chain for leachate treatment, achieving synergistic efficiency improvement in pollutant reduction and resource utilization;

[0071] (2) Microbial pretreatment and black soldier fly high - efficiency reduction technology: Reduce the toxicity of leachate through pretreatment with salt - tolerant composite bacteria, and cooperate with temperature gradient regulation and optimization of the C / N ratio of auxiliary substrates to reduce the leachate volume by 80 - 90%, improving the acceptance capacity of black soldier flies for leachate;

[0072] (3) Membrane separation and carbon source optimization integration technology: Concentrate the remaining high - COD - equivalent leachate through membrane separation and use it as a special carbon source, mix it with external carbon sources to prepare a low - COD - equivalent functional solution, while reducing the salinity to less than 0.5% and improving biodegradability;

[0073] (4) High - value resource recovery technology: Through a hierarchical extraction process for black soldier fly larvae, successively extract protein, chitin and organic fertilizers to achieve high - value utilization of resources throughout the whole chain;

[0074] (5) Intelligent monitoring and adaptive regulation: Real - time monitor the operation parameters of each treatment unit through an intelligent sensor network, and use an adaptive algorithm to automatically adjust process parameters to optimize system performance.

[0075] The present invention has the following beneficial effects compared with the prior art:

[0076] (1) Significantly improved treatment efficiency: The leachate volume reduction rate reaches 80 - 90%, which is more than 30% higher than traditional technologies;

[0077] (2) Significantly reduced salinity and toxic substances: Through microbial pretreatment and carbon source optimization, the salinity is reduced to less than 0.5%, and the removal rate of toxic substances reaches more than 95%;

[0078] (3) High degree of resource utilization: The yield of black soldier fly larvae is high, the protein content reaches 40 - 45%, the chitin content reaches 5 - 8%, and the nutrients of the residue organic fertilizer are comprehensive;

[0079] (4) Significantly economical: The operating cost is 40% lower than traditional membrane separation technology, the comprehensive value of products is high, and the system investment payback period is short;

[0080] (5) Good environmental friendliness: The system has near - zero emissions, low energy consumption and a small carbon footprint.

[0081] The specific implementation process is as follows:

[0082] Example 1: Construction of an integrated system for leachate treatment and resource recovery

[0083] The integrated system for leachate treatment and resource recovery of the present invention includes a pretreatment module 1, a black soldier fly biological reduction module 2, a leachate concentration module 3, a carbon source optimization module 4, a resource recovery module 5, and an intelligent monitoring module.

[0084] The pretreatment module 1 includes a pH adjustment unit, a precipitation separation unit, and a microbial pretreatment unit. The pH adjustment unit uses an automatic dosing system to adjust the pH of the leachate to the range of 6.5 - 7.5; the precipitation separation unit removes large particulate suspended matters and heavy metals through coagulation precipitation; the microbial pretreatment unit inoculates a salt-tolerant composite bacterial community (an optimized combination of Halomonas sp., Bacillus sp., and Pseudomonas sp.), and pretreats for 24 - 48 hours at 28°C to reduce the toxicity of the leachate and increase the BOD5 / COD from the initial 0.1 - 0.2 to 0.25 - 0.35.

[0085] The black soldier fly biological reduction module 2 adopts a multi-stage temperature gradient design, including a primary treatment unit, an intermediate treatment unit, and a high-temperature treatment unit. The temperature of the primary treatment unit is controlled at 28 - 32°C, mainly for the adaptation period of black soldier fly larvae; the temperature of the intermediate treatment unit is 33 - 37°C to promote the rapid growth of black soldier fly larvae; the temperature of the high-temperature treatment unit is 38 - 42°C to accelerate the evaporation of the leachate. The auxiliary substrate is prepared according to the ratio of straw, wood chips, and fruit and vegetable waste of 3:2:5, the C / N ratio is controlled at 20 - 25:1, and the mass ratio of the leachate to the auxiliary substrate is 3:1. During the leachate treatment process, 15 - 25% of the leachate is absorbed by the black soldier fly larvae themselves, 60 - 75% of the leachate is removed by evaporation through temperature gradient control, and the remaining 10 - 20% of the leachate is transferred to the concentration module.

[0086] The leachate concentration module 3 includes a microfiltration device, an ultrafiltration device, and a storage tank. The microfiltration pore size is 0.45 μm to remove solid impurities in the leachate; the ultrafiltration uses a hollow fiber membrane with a molecular weight cut-off value of 10,000 Da to remove macromolecular organic matters and colloidal substances. The COD equivalent of the concentrated leachate is increased from the initial 40,000 - 60,000 mg / L to 180,000 - 250,000 mg / L, and the concentration multiple is 4 - 5 times.

[0087] The carbon source optimization module 4 includes a carbon source preparation unit, a mixing reaction unit, and a performance testing unit. The carbon source preparation unit mixes the concentrated leachate with molasses and food processing waste liquid according to the ratio of 1:3:6, and adds trace element regulators (including Fe 2+ 、Mg 2+ 、Mn 2+etc.); the mixing reaction unit stirs and reacts for 4 - 6 hours at 30°C to promote the mutual solubility of organic components; the performance testing unit monitors in real time the indicators such as COD, BOD5, pH, and salinity of the prepared solution. The COD of the prepared low-COD equivalent solution is 6000 - 9000 mg / L, the salinity is reduced to 0.3 - 0.5%, and the BOD5 / COD is increased to 0.4 - 0.5, which is suitable for the addition of carbon sources in subsequent biological treatment processes.

[0088] The resource recovery module 5 includes a separation device, a protein extraction unit, a chitin extraction unit, and a fertilizer preparation unit. The separation device uses a vibrating screen to separate black soldier fly larvae from residual materials; the protein extraction unit uses an alkaline protein dissolution - acidic isoelectric point precipitation process to extract protein, with an extraction rate of over 85%; the chitin extraction unit uses a mild alkali extraction technology to extract chitin, with an extraction rate of over 80%; the fertilizer preparation unit mixes the residue after extraction with the residual materials, adds beneficial microorganisms (such as Bacillus subtilis, actinomycetes, etc.) and ferments for 7 - 10 days to prepare organic fertilizer, with the nitrogen, phosphorus, and potassium content ≥ 5%.

[0089] The intelligent monitoring module configures a multi-parameter sensor network to monitor in real time parameters such as temperature, humidity, pH, COD, dissolved oxygen, and the growth status of black soldier flies, and automatically adjusts the process parameters through a PLC control system and an adaptive optimization algorithm to optimize the system performance.

[0090] Example 2: Treatment of landfill leachate

[0091] Treat the leachate generated from a certain landfill. The initial characteristics of the leachate are: COD 55000 mg / L, BOD5 6800 mg / L, NH3-N 2500 mg / L, salinity 3.2%, pH 5.8.

[0092] The pretreatment module 1 adjusts the pH to 7.0, adds 200 mg / L of coagulant PAC, and after removing suspended solids by precipitation, inoculates a salt-tolerant composite bacterial community for pretreatment for 36 hours, and the BOD5 / COD is increased to 0.28.

[0093] The black soldier fly biological reduction module 2 adds a proportionally prepared auxiliary substrate (straw, wood chips, and fruit and vegetable waste), and the mass ratio of leachate to the auxiliary substrate is 3:1. It is treated for 3 days, 2 days, and 2 days under three temperature gradient conditions of 30°C, 35°C, and 40°C respectively. After treatment, the volume of the leachate is reduced by 86%, among which 21% is accepted by black soldier fly larvae, 65% is removed by evaporation, and the remaining 14% of the leachate is transferred to the concentration module.

[0094] The leachate concentration module 3 processes through microfiltration and ultrafiltration to concentrate the COD of the remaining leachate to 220000 mg / L, and the concentration multiple is 4 times.

[0095] The carbon source optimization module 4 mixes concentrated leachate with molasses and food processing waste liquid in a ratio of 1:3:6, adds a trace element regulator, and reacts for 5 hours to prepare a functional carbon source solution with a COD of 7500 mg / L, a salinity of 0.42%, and a BOD5 / COD of 0.48.

[0096] The resource recovery module 5 collects 12.5 kg (fresh weight) of black soldier fly larvae per 100 L of leachate. After protein extraction, 2.1 kg of high-quality protein (protein content 93%) and 0.32 kg of chitin (purity ≥ 90%) are obtained. The residue and residual materials are used to prepare 15 kg of organic fertilizer (total nitrogen, phosphorus, and potassium content 6.5%).

[0097] Example 3: System performance comparison test

[0098] The system of the present invention and a traditional membrane treatment system were subjected to a 60-day continuous operation comparison test. The results are shown in the following table:

[0099]

[0100]

[0101] Example 4: Verification of the utilization effect of the functional carbon source

[0102] The functional carbon source solution produced by the system of the present invention was applied to the denitrification process of a sewage treatment plant and compared with a traditional externally added carbon source (sodium acetate). The results are as follows:

[0103] Index Functional carbon source of the present invention Traditional sodium acetate Total nitrogen removal rate 92.5％ 85.3％ Denitrification rate (mgN / gVSS·h) 3.8 3.2 Effect of improving microbial activity Significant General Carbon source utilization efficiency (kgN / kgCOD) 0.12 0.09 Carbon source cost (yuan / kgN removal) 8.5 15.2

[0104] The functional carbon source produced by the present invention is rich in easily degradable organic matter and trace nutrient elements, has a significant promoting effect on microbial activity, improves the denitrification efficiency and carbon source utilization efficiency, and reduces the operating cost.

[0105] Example 5: Effect of improving the degree of intelligence

[0106] Compare the operating effects of traditional manual operation and adaptive control of the intelligent monitoring module:

[0107]

[0108]

[0109] The intelligent monitoring module optimizes the system operating parameters through real-time data collection and adaptive control algorithms, improves the growth efficiency of black soldier flies and the stability of leachate treatment, and reduces the labor cost.

[0110] In the present invention, an organic and interconnected technical chain is formed among various modules, which synergistically enhance the efficiency. The pretreatment module reduces the toxicity of the leachate, creating suitable conditions for the biological reduction by black soldier flies; the biological reduction by black soldier flies achieves a significant reduction in the leachate volume and simultaneously produces high-value biomass; the leachate concentration module increases the organic matter concentration, providing a basis for carbon source optimization; the carbon source optimization module realizes the resource utilization of the organic matter in the leachate; the resource recovery module realizes the multi-stage and hierarchical utilization of the products of black soldier flies, maximizing the economic benefits.

[0111] The system of the present invention is applicable to the treatment of high-concentration and high-salinity leachate generated by various waste treatment facilities, and is particularly suitable for the treatment and resource utilization of leachate from food waste treatment plants, waste transfer stations and landfills. The system scale can be modularly expanded according to actual needs, and the treatment capacity can be expanded from 5 m 3 / d to 500 m 3 / d, having broad application prospects.

[0112] The above are only embodiments of the present invention. Specific technical solutions and / or common knowledge such as characteristics well known in the art are not described in detail herein. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application shall be subject to the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. A leachate treatment and recovery system for black soldier fly biological reduction and carbon source optimization, characterized in that Including: A pretreatment module for adjusting the pH, removing impurities, and performing microbial pretreatment on the initial leachate to reduce the toxicity of the leachate and improve its biodegradability, thereby obtaining pretreated leachate; A black soldier fly bioreduction module that processes the pretreated leachate with black soldier fly larvae and adds a specific auxiliary substrate to reduce the volume of the leachate and obtain the remaining leachate; A leachate concentration module that concentrates and collects the remaining leachate through membrane separation technology to obtain concentrated leachate; A carbon source optimization module that mixes the concentrated leachate with an external carbon source to prepare a functional solution with a low COD equivalent, while reducing salinity and improving biodegradability to obtain a mixed carbon source; A resource recovery module that hierarchically extracts the black soldier fly larvae involved in the pretreatment of the permeate in the black soldier fly bioreduction module to obtain protein, chitin, and organic fertilizer.

2. The leachate treatment and recovery system for black soldier fly biological reduction and carbon source optimization according to claim 1, characterized in that, The pretreatment module includes a pH adjustment unit, a precipitation separation unit, and a microbial pretreatment unit; the pH adjustment unit uses an automatic dosing system to adjust the pH of the leachate to the range of 6.5 - 7.5; the precipitation separation unit removes large particle suspensions and heavy metals through coagulation precipitation; the microbial pretreatment unit inoculates a salt-tolerant composite bacterial community and pretreats it at 28°C for 24 - 48 hours to increase the BOD5 / COD of the leachate.

3. The leachate treatment and recovery system for black soldier fly biological reduction and carbon source optimization according to claim 1, characterized in that, The black soldier fly bioreduction module adopts a multi-stage temperature gradient design, including a primary treatment unit, an intermediate treatment unit, and a high-temperature treatment unit; the temperature of the primary treatment unit is controlled at 28 - 32°C, the temperature of the intermediate treatment unit is 33 - 37°C, and the temperature of the high-temperature treatment unit is 38 - 42°C; the specific auxiliary substrate is prepared according to the ratio of straw, wood chips, and fruit and vegetable waste of 3:2:5, the C / N ratio is controlled at (20 - 25):1, and the mass ratio of the leachate to the auxiliary substrate is 3:

1.

4. The leachate treatment and recovery system for black soldier fly bioreduction and carbon source optimization according to claim 1, characterized in that, The leachate concentration module includes a microfiltration device, an ultrafiltration device, and a storage tank; the microfiltration pore size of the microfiltration device is 0.45μm, which is used to remove solid impurities in the leachate; the ultrafiltration device uses a hollow fiber membrane with a molecular weight cut-off value of 10000Da to remove macromolecular organic matter and colloidal substances.

5. The leachate treatment and recovery system for black soldier fly biological reduction and carbon source optimization according to claim 1, wherein The carbon source optimization module includes a carbon source preparation unit, a mixing reaction unit, and a performance testing unit; the carbon source preparation unit mixes the concentrated leachate with molasses and food processing waste liquid according to the ratio of 1:3:6 and adds a trace element regulator; the mixing reaction unit stirs and reacts at 30°C for 4 - 6 hours; the performance testing unit monitors the COD, BOD5, pH, and salinity indicators of the prepared solution in real time.

6. The leachate treatment and recovery system for black soldier fly biological reduction and carbon source optimization according to claim 1, wherein The resource recovery module includes a separation device, a protein extraction unit, a chitin extraction unit, and a fertilizer preparation unit; the separation device uses a vibrating screen to separate black soldier fly larvae from residual materials; the protein extraction unit extracts protein using an alkaline protein dissolution - acidic isoelectric point precipitation process; the chitin extraction unit extracts chitin using a mild alkali extraction technique; the fertilizer preparation unit mixes the extracted residue with the residual materials and adds beneficial microorganisms to ferment and prepare organic fertilizer.

7. A method for treating and recycling leachate by reducing the amount of black soldier fly and optimizing carbon sources, characterized in that, The leachate treatment and recovery system for black soldier fly biological reduction and carbon source optimization described in claim 1 comprises the following steps: Step 1, using a pretreatment module to adjust the pH of the initial leachate, remove impurities and perform microbial pretreatment to obtain pretreated leachate; Step 2, sending the pretreated leachate into the black soldier fly biological reduction module, and treating it with black soldier fly larvae and a specific auxiliary substrate to achieve volume reduction of the leachate and obtain the remaining leachate; Step 3, sending the remaining leachate treated by the black soldier fly biological reduction module into the leachate concentration module, and concentrating it by membrane separation technology to obtain concentrated leachate; Step 4, sending the concentrated leachate into the carbon source optimization module, mixing it with an external carbon source to prepare a functional solution with a low COD equivalent, and obtaining a mixed carbon source; Step 5, performing hierarchical extraction on the black soldier fly larvae, and obtaining protein, chitin and organic fertilizer through a resource recovery module.

8. The method for treating and recycling leachate with biological reduction of black soldier fly and carbon source optimization according to claim 7, characterized in that, In the microbial pretreatment step of Step 1, inoculating a salt-tolerant composite bacterial community and pretreating it at 28°C for 24 - 48 hours to increase the BOD5 / COD from the initial 0.1 - 0.2 to 0.25 - 0.

35.

9. The method for treating and recycling leachate with black soldier fly for biological reduction and carbon source optimization according to claim 7, characterized in that, In the black soldier fly biological reduction step of Step 2, during the treatment of the pretreated leachate, the black soldier fly larvae themselves accept 15 - 25% of the leachate, 60 - 75% of the leachate is removed by evaporation through temperature gradient control, and the remaining leachate is transferred to the concentration module.

10. The method for treating and recovering leachate with black soldier fly for biological reduction and carbon source optimization according to claim 7, wherein, In the carbon source optimization step of Step 4, the COD of the prepared low-COD equivalent solution is 5000 - 10000 mg / L, the salinity is reduced to less than 0.5%, and the BOD5 / COD is increased to more than 0.4.

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