A method for filtering high-oil solid sewage using an aged landfill body and a method for preparing a carbon source supplement solution

Abstract

The present invention discloses a method for filtering high-oil solid wastewater using an old landfill body and a method for preparing a carbon source supplement liquid. The present invention uses urban domestic wet garbage as the raw material of the carbon source supplement liquid and cooperates with the landfill body, and can simultaneously process the wet garbage slurry with high oil and high impurities and the old leachate with high nitrogen and low carbon-nitrogen ratio, solving the key problems in the operation and management of the garbage plant and effectively improving the leachate treatment capacity. The wet garbage slurry is taken for pretreatment, and the landfill body is used as a carrier for anaerobic fermentation and screening filtration to prepare a high-quality carbon source supplement liquid, which helps to supplement the problem of low carbon content in the old leachate and ensures the quality of the sewage treatment effluent. At the same time, the effluent will not cause an increase in COD, total nitrogen, and total phosphorus. The carbon source supplement liquid provided by the present invention does not require additional raw material acquisition costs, and the slurry and the old leachate are processed in a coordinated manner, thereby improving the overall efficiency of the garbage treatment plant.

Description

Technical Field

[0001] The invention relates to the technical field of leachate treatment and solid waste resource recycling, in particular to a method for filtering high-oil-solid wastewater using an old landfill and a method for preparing a carbon source supplement liquid. Background Art

[0002] Currently, aged leachate in my country is characterized by high ammonia nitrogen content and a severely insufficient carbon-nitrogen ratio, making it a key challenge in the operation and management of municipal solid waste treatment plants. Leachate treatment processes primarily remove nitrogen, COD, oil content, and suspended solids to ensure that the leachate meets discharge standards.

[0003] Anaerobic denitrification is a common biological denitrification method, and its denitrification effect is closely related to the type and content of carbon sources in the leachate. Due to the severe shortage of carbon sources in aged leachate in my country, there is an urgent need to artificially add carbon sources to promote the denitrification biological denitrification process.

[0004] To achieve optimal denitrification of aged leachate, traditional carbon source supplementation involves adding liquid single organic compounds, such as glucose, acetic acid, methanol, and sodium acetate. However, these supplements increase treatment plant operating costs, and methanol supplementation is flammable and explosive, posing a safety hazard. Consequently, in recent years, many researchers have begun researching new, cost-effective, and efficient carbon sources.

[0005] For example, adding solid cellulose carbon sources, such as straw, rice husks, peanut shells, and sawdust, has been proposed. However, since the carbon source is primarily cellulose, it has low utilization rates and unstable treatment effects. Another approach has been to add liquid mixed organic carbon sources, such as fresh landfill leachate, hydrolyzed fermentation broth, and organic industrial wastewater.

[0006] In order to reduce economic pressure and optimize denitrification efficiency, using fresh landfill leachate as a carbon source supplement is a preferred method.

[0007] However, with the vigorous promotion of wet garbage biocomposting energy recovery technology (bioenergy treatment), the amount of wet garbage entering landfills and incineration plants has dropped sharply, and the amount of leachate produced by landfills and incineration plants has been greatly reduced, which can no longer meet the carbon source demand for anaerobic denitrification of the leachate.

[0008] At the same time, wet garbage slurry with high oil content and high solid suspension characteristics also faces treatment difficulties. Summary of the Invention

[0009] In order to solve the above-mentioned problems of difficulty in treating wet garbage slurry and shortage of fresh leachate as carbon source supplement.

[0010] The present invention proposes to perform extrusion and preliminary screening pretreatment on wet garbage before entering bioenergy treatment to produce wet garbage slurry feed with high oil content and high solid suspension. The old landfill pile is used as an anaerobic and filtration device for the wet garbage slurry feed to prepare a carbon source supplement liquid, which is then synergistically treated with the old leachate. In this way, the economic, efficiency and safety problems caused by the treatment of the raw slurry and the insufficient carbon content of the leachate plant can be solved at the same time.

[0011] In order to achieve the purpose of the present invention, the technical solution adopted is:

[0012] A method for filtering high-oil-solid wastewater using an old landfill and a method for preparing a carbon source supplement liquid include the following steps:

[0013] The wet garbage entering the bioenergy treatment plant is subjected to extrusion pretreatment for 5 to 12 hours to obtain the raw slurry of urban domestic garbage and wet garbage with high salt, oil and solid suspended matter content;

[0014] The wet garbage slurry is placed in a screening tank for preliminary screening. The initial screening adopts a gravity screening method and then the valve under the screening tank is opened after standing to obtain and collect the wet garbage primary screening slurry for the next step of processing;

[0015] The effluent from the wet garbage primary screening slurry is re-injected into the old landfill, and the old landfill is used for anaerobic fermentation and filtration adsorption treatment to obtain a denitrification carbon source supplement for the old leachate;

[0016] The denitrification carbon source supplement liquid is injected into the aged leachate and a biological filter bed is selected for full reaction. Specifically, the denitrification carbon source supplement liquid is gradually injected into the biological trickle bed of the aged leachate to obtain a mixture of the carbon source supplement liquid and the aged leachate.

[0017] In a preferred embodiment of the present invention, the standing time is 10-12 hours, preferably 12 hours.

[0018] In a preferred embodiment of the present invention, the density of the wet garbage primary screening slurry after extrusion is 600-700 kg / m 3 .

[0019] In a preferred embodiment of the present invention, the parameter indicators of the aged landfill are as follows:

[0020] COD is 2000-3000 mg / L;

[0021] Ammonia nitrogen is 2000-3000 mg / L;

[0022] Total nitrogen is 2500-3800 mg / L;

[0023] Total phosphorus is 150-250 mg / L.

[0024] In a preferred embodiment of the present invention, the outlet water is recharged 1 to 4 times per week.

[0025] In a preferred embodiment of the present invention, the rate of water re-injection is 6.6×10 -6 m / s.

[0026] In a preferred embodiment of the present invention, the anaerobic fermentation temperature inside the aged landfill is 30-35°C.

[0027] In a preferred embodiment of the present invention, the waiting period for the initial recharge is 3 to 5 days before the carbon source supplement solution is taken out.

[0028] In a preferred embodiment of the present invention, the mixing ratio of the carbon source supplement solution to the aged leachate is 0.5-1.5:10.

[0029] In a preferred embodiment of the present invention, the carbon source supplement solution and the aged leachate are mixed and reacted for 1 to 2 days.

[0030] The beneficial effects of the present invention are:

[0031] This invention provides a method for filtering high-oil-solid wastewater and preparing a carbon source supplement using aged landfills. This method uses wet garbage slurry as the raw material, and uses the aged landfill as a carrier for anaerobic fermentation and filtration to produce a high-quality carbon source supplement. After the carbon source supplement and leachate are synergistically treated, the aged leachate achieves COD removal rates exceeding 90%, total nitrogen removal rates exceeding 80%, ammonia nitrogen removal rates exceeding 95%, and total phosphorus removal rates exceeding 95%.

[0032] At the same time, the effluent does not cause an increase in COD, total nitrogen, or total phosphorus levels. This invention simultaneously treats high-oil-solids raw slurry and aged leachate, eliminating the need for additional raw material costs. This avoids direct addition of high-oil-solids raw slurry to the leachate conditioning tank, which can cause pumping system failures during operation. This significantly improves treatment plant resource utilization and significantly enhances the treatment of aged leachate, resulting in multiple economic and social benefits. Data from specific examples demonstrate that the landfill treatment raw slurry proposed in this invention can be used as a high-quality carbon source supplement. DETAILED DESCRIPTION

[0033] The present invention discloses a method for filtering high-oil-solid wastewater using an aged landfill and a method for preparing a carbon source supplement. An economical carbon source supplement is prepared by using wet garbage high-oil-solid slurry as the raw material and the landfill as a carrier for anaerobic fermentation and screening and filtration. The technical solution of the present invention is clearly and completely described in conjunction with the embodiments. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] This implementation is based on the collaborative work of the Shanghai Laogang Municipal Waste Phase I and II Bioenergy Center and the Phase IV Landfill. The landfill pile is used to perform anaerobic fermentation and screening and filtration on the wet garbage slurry to prepare the carbon source supplement liquid in the denitrification process of the aged leachate.

[0036] A method for filtering high-oil-solid wastewater using an old landfill and a method for preparing a carbon source supplement liquid include the following steps:

[0037] (1) Wet garbage pretreatment:

[0038] Step 1: Pour the wet garbage into the extrusion pool of the bio-energy treatment center for extrusion pretreatment. The extrusion time is 5 to 12 hours to obtain the wet garbage raw slurry feed.

[0039] The wet garbage components include food waste, leftovers, expired food, melon peels, fruit cores, flowers and plants, etc. The pH value of the wet garbage raw pulp feed is 3.99, COD is 128000 mg / L, solid suspended matter content is 45660 mg / L, and oil content is 4450.528 mg / L;

[0040] Step 2: Transfer the slurry feed to a well-sealed screening bucket for initial screening. This is done by gravity screening and allowed to rest for 12 hours. Subsequently, the valve at the bottom of the screening bucket is opened, allowing gravity to drain the slurry from the bottom. This wet waste slurry is then collected in a fermentation bucket.

[0041] The gravity screening method preferably uses a screening barrel with a total column height of 65 cm, which contains filter material with a full diameter of 5-10 mm recycled aggregate; the pH value of the primary screening slurry is 7.31, the COD is 71100 mg / L, the solid suspended matter content is 6620 mg / L, the oil content is 35.086 mg / L, and it is black and obviously anaerobic.

[0042] (2) Obtain various parameters of aged leachate:

[0043] Step 1: Determination of aged leachate.

[0044] The aged leachate has a COD of 2000-3000 mg / L, ammonia nitrogen of 2000-3000 mg / L, total nitrogen of 2500-3800 mg / L, and total phosphorus of 150-250 mg / L.

[0045] (3) The above-mentioned primary screening slurry is subjected to anaerobic fermentation and separation treatment using the old landfill:

[0046] First, the primary screened slurry is poured into an old landfill model.

[0047] The aged landfill model adopts the material component characteristics of Shanghai Laogang Phase IV landfill for simulation;

[0048] The perfusion process preferably adopts a low recharge frequency of 3 times per week; a low recharge speed of 6.6×10-6 m / s; an internal ambient temperature of the landfill model of 30-35° C.; and a fermentation time of 216 hours.

[0049] Second, unseal and take the supernatant in the fermentation barrel under static state to obtain the carbon source supplement liquid.

[0050] The anaerobic fermentation process is preferably kept in a static and sealed state throughout the entire process to prevent air from entering the slurry, resulting in the absence of an anaerobic space inside the slurry, which would affect the effect of the anaerobic reaction;

[0051] The removal rates of COD, suspended solids and oil content of the carbon source supplement liquid are as high as 58.9%, 97.1% and 99.0% respectively.

[0052] (4) Inject the carbon source supplement obtained in (3) into the aged leachate for full reaction:

[0053] The carbon source supplement obtained in (3) is gradually injected into the biological trickle bed of the aged leachate. The mixing ratio of the wet garbage carbon source supplement and the aged leachate is 1:10. The mixing reaction time is 1 to 2 days to obtain a mixed solution after synergistic treatment.

[0054] As can be seen from Table 1, the carbon source supplement solution prepared according to this embodiment can effectively remove the nitrogen content in the aged leachate and meet the carbon demand for leachate treatment.

[0055] Table 1 Effect of wet garbage carbon source supplement solution on synergistic leachate sewage treatment

[0056]

[0057] The above-mentioned Example 1 is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for filtering high-oil-solid wastewater using old landfills and a method for preparing a carbon source supplement solution, characterized in that: The steps include: The wet garbage entering the bioenergy treatment plant is subjected to extrusion pretreatment for 5 to 12 hours to obtain the raw slurry of urban domestic garbage and wet garbage with high salt, oil and solid suspended matter content; The density of the wet garbage primary screening slurry after extrusion is 600-700 kg / m 3 ; The wet garbage slurry is placed in a screening tank for preliminary screening. The initial screening adopts a gravity screening method and then the valve under the screening tank is opened after standing to obtain and collect the wet garbage primary screening slurry for the next step of processing; The effluent from the wet garbage primary screening slurry is re-injected into the old landfill, and the old landfill is used for anaerobic fermentation and filtration adsorption treatment to obtain a denitrification carbon source supplement for the old leachate; The parameter indicators of the aged landfill are as follows: COD is 2000-3000 mg / L; Ammonia nitrogen is 2000-3000 mg / L; Total nitrogen is 2500-3800 mg / L; Total phosphorus is 150-250 mg / L; The effluent recharge is 1 to 4 times per week; The water recharge rate is 6.6×10 -6 m / s; The anaerobic fermentation temperature inside the aged landfill is 30-35°C; After the initial re-injection waiting period of 3 to 5 days, the carbon source supplement solution is taken out; Injecting the denitrification carbon source supplement into the aged leachate and selecting a biological filter bed for full reaction, specifically, gradually injecting the denitrification carbon source supplement into the biological trickle bed of the aged leachate to obtain a mixture of the carbon source supplement and the aged leachate; The mixing ratio of the carbon source supplement and the aged leachate is 0.5 to 1.5:10; The carbon source supplement solution and the aged leachate are mixed and reacted for 1 to 2 days.

2. The method for filtering high-oil-solid wastewater and preparing carbon source supplement liquid using an old landfill as claimed in claim 1, characterized in that: The standing time is 10-12 hours.

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