Biomass carbon source production system using garbage transfer station leachate

Abstract

The invention relates to a biomass carbon source production system using leachate of a waste transfer station, which comprises a grating pool, an adjusting tank, a sludge tank, a reaction tank, a return sludge tank, a sludge storage tank and a carbon source finished product warehouse, and is characterized in that the collected landfill leachate is subjected to biological anaerobic treatment, and during treatment, large-particle-size impurities and fibers of the leachate are discharged into sludge in the adjusting tank; macromolecular organic matters are fermented in the reaction tank to obtain micromolecular organic acids, and the micromolecular organic acids are intensively converted into acetic acid, propionic acid and the like, which are different from the existing treatment mode of living-source organic waste liquids such as kitchen and kitchen garbage slurry, and are used for processing and treating garbage transfer station leachate with lower COD (Chemical Oxygen Demand) concentration and more complex components. The landfill leachate which is originally sent to a sewage treatment plant for centralized treatment is subjected to resource utilization, so that high-value low-carbon resource utilization of the wastewater and synergistic interaction of reducing pollution and carbon are realized.

Description

Technical Field

[0001] This invention belongs to the technical field of carbon source production systems, and particularly relates to a biomass carbon source production system using leachate from a waste transfer station. Background Technology

[0002] Leachate from waste transfer stations is a high-concentration organic wastewater generated from the combined effects of water content in the waste itself, rainwater infiltration, and organic matter degradation. Its quality is highly polluted and highly volatile. Its chemical oxygen demand (COD) concentration can reach 20,000-40,000 mg / L, with nitrogen content exceeding 1,000 mg / L, and it contains heavy metals such as lead and cadmium, as well as high-salt components. With prolonged storage, the proportion of recalcitrant organic matter such as humic acid in the leachate increases, significantly reducing its biodegradability (BOD5 / COD ratio). Simultaneously, the water quality and quantity fluctuate dramatically with the seasons and waste composition, greatly increasing the difficulty of treatment. If discharged untreated, it will lead to eutrophication of water bodies and accumulation of heavy metals in the soil, threatening the ecosystem and human health through the food chain.

[0003] The current mainstream treatment technology is a combined process of "pretreatment-biological treatment-advanced treatment," after which the leachate is incorporated into the municipal sewage network and sent to sewage treatment plants for centralized treatment. Leachate is first pretreated to remove suspended solids; the biological stage mainly uses A / O and membrane bioreactors (MBR); and advanced treatment often employs nanofiltration (NF) and reverse osmosis (RO), with MBR+NF / RO combinations accounting for over 65%. However, this traditional process suffers from bottlenecks such as a 20%-30% membrane concentrate ratio and severe membrane fouling; furthermore, deploying a leachate treatment unit at a landfill transfer station requires a large area and incurs high daily operating costs. Achieving efficient treatment and resource utilization of landfill leachate is currently one of the key directions of scientific research.

[0004] Meanwhile, most municipal wastewater treatment plants suffer from poor treatment efficiency due to insufficient carbon source supply. Effectively addressing this carbon source shortage is one of the key ways to improve nitrogen and phosphorus removal efficiency and achieve compliant wastewater discharge. Currently, municipal wastewater treatment plants commonly use traditional single commercial carbon sources (methanol, sodium acetate, glucose, etc.) or composite commercial carbon sources (hybrid acids and alcohols). These traditional carbon sources suffer from poor safety, high prices, and complex compositions, significantly increasing wastewater treatment costs. Therefore, designing a biomass carbon source production system utilizing leachate from waste transfer stations that promotes waste resource reuse and reduces carbon source costs has become an urgent technical challenge. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a biomass carbon source production system using leachate from a waste transfer station.

[0006] The technical solution of this invention is a biomass carbon source production system using leachate from a waste transfer station, comprising a bar screen, a regulating tank, a sludge tank, a reaction tank, a return sludge tank, a sludge storage tank, and a finished carbon source silo. The carbon source production process includes... s1 collects leachate from the waste transfer station and feeds it into a bar screen, where the bar screens intercept large-diameter impurities and fibers in the leachate. s2, after intercepting impurities, the leachate is pumped from the bar screen into the equalization tank, and then an alkaline solution is introduced into the equalization tank to adjust the pH value of the leachate to 8-9, so that heavy metals in the leachate are precipitated and removed. s3, the sediment in the regulating tank is filtered, and the filtered sediment is transported to the sludge tank for sludge discharge treatment; s4, the filtered leachate is pumped from the regulating tank into the reaction tank, and anaerobic bacteria are inoculated in the reaction tank to hydrolyze and acidify the macromolecular organic matter in the leachate. s5. The pH value in the reaction tank is monitored by a pH sensor. By adding an acidic solution, the pH value of the leachate is maintained at 5-6 for acid fermentation treatment, or an alkaline solution is added to maintain the pH value of the leachate at 8-9 for alkaline fermentation treatment, to generate small molecule organic acids. s6, the sludge produced by the biological reaction is discharged from the reaction tank into the return sludge tank; s7. Use a sludge concentration meter to monitor the MLSS concentration in the reaction tank, return part of the sludge in the return sludge tank to the reaction tank, and discharge the remaining sludge into the sludge storage tank. s8, after the sludge settles in the reaction tank, an organic liquid biomass carbon source containing small molecule organic acids is obtained and pumped into the carbon source finished product silo for storage. S9 transports organic liquid biomass carbon sources from the finished carbon source warehouse to the carbon source addition point of the wastewater treatment equipment.

[0007] As a further improvement of the present invention, the alkaline solution is a NaOH solution.

[0008] As a further improvement of the present invention, the acidic solution is Solution.

[0009] As a further improvement of the present invention, alkaline fermentation is the optimal method for treating macromolecular organic matter with anaerobic bacteria.

[0010] As a further improvement of the present invention, the acid fermentation treatment includes a hydrolysis stage, an acidification stage, and a volatile organic acid (VFA) production stage. In the hydrolysis stage, hydrolytic fermentation bacteria decompose macromolecular organic matter, controlling the pH of the leachate to 6.5-7.5 and the residence time (HRT) to 1-3 days. In the acidification stage, acid-producing bacteria convert the hydrolysis products into bioavailable organic acids, controlling the pH of the leachate to 5.0-6.0 and the residence time (HRT) to 1-2 days. In the VFA production stage, hydrogen-producing acetic acid bacteria convert organic acids into acetic acid, propionic acid, butyric acid, and valeric acid, controlling the pH of the leachate to 5.0-6.0 and the residence time (HRT) to 1-2 days. The difference between the alkaline fermentation treatment and the acid fermentation treatment is that the pH of the acidification stage and the VFA production stage is controlled at 8.0-9.0.

[0011] As a further improvement of the present invention, the hydrolysis stage includes low-temperature fermentation and medium-temperature fermentation. The temperature of the leachate is controlled at 10-20°C during low-temperature fermentation and at 20-40°C during medium-temperature fermentation.

[0012] As a further improvement of the present invention, a variable frequency stirrer is installed in the reaction vessel, and the speed of the variable frequency stirrer during the hydrolysis acidification treatment is 30-45 r / min.

[0013] As a further improvement of the present invention, during the hydrolysis acidification treatment, the MLSS concentration in the reaction vessel is less than 10 g / L.

[0014] By employing the above method, the collected landfill leachate is subjected to biological anaerobic treatment through the coordinated use of the grit chamber, equalization tank, sludge tank, reaction tank, return sludge tank, sludge storage tank, and carbon source finished product silo of this production system. During the treatment, not only are large-particle impurities and fibers in the leachate discharged as sludge, but large-molecule organic matter is also fermented to obtain small-molecule organic acids, which are then converted into acetic acid. This method differs from existing treatment methods for organic waste liquids from domestic sources such as kitchen waste and food waste slurry. It processes leachate from landfill transfer stations, which has a lower COD concentration and more complex composition, to obtain leachate biomass carbon source that can replace commercial carbon sources. This resource utilization of landfill leachate that should have been sent to sewage treatment plants for centralized treatment achieves high-value, low-carbon resource utilization of wastewater and synergistic effects of pollution reduction and carbon reduction.

[0015] By controlling the MLSS concentration of leachate during fermentation to be much lower than that of traditional fermentation processes (20-40 g / L), fermentation can be carried out under both acidic and alkaline conditions, efficiently producing biomass carbon sources. While ensuring a low COD loss rate, hydrogen-producing and acetic acid-producing bacteria are used to convert organic acids into acetic acid, propionic acid, butyric acid, and valeric acid, thereby increasing the conversion rate of VFAs that can be directly used for wastewater treatment. This transforms leachate from waste transfer stations, which originally had poor biodegradability (i.e., a low B / C ratio), into a high-quality biomass carbon source with better biodegradability and a higher B / C ratio. Attached Figure Description

[0016] Figure 1 The diagram shown is a schematic diagram of the carbon source production system of the present invention. Detailed Implementation

[0017] like Figure 1 The system shown is a biomass carbon source production system using leachate from a landfill transfer station, comprising a bar screen, equalization tank, sludge tank, reaction tank, return sludge tank, sludge storage tank, and finished carbon source silo. The carbon source production process includes... s1 collects leachate from the waste transfer station and feeds it into a bar screen, where the bar screens intercept large-diameter impurities and fibers in the leachate. s2, after intercepting impurities, the leachate is pumped from the bar screen into the equalization tank, and then an alkaline solution is introduced into the equalization tank to adjust the pH value of the leachate to 8-9, so that heavy metals in the leachate are precipitated and removed. s3, the sediment in the regulating tank is filtered, and the filtered sediment is transported to the sludge tank for sludge discharge treatment; s4, the filtered leachate is pumped from the regulating tank into the reaction tank, and anaerobic bacteria are inoculated in the reaction tank to hydrolyze and acidify the macromolecular organic matter in the leachate. s5. The pH value in the reaction tank is monitored by a pH sensor. By adding an acidic solution, the pH value of the leachate is maintained at 5-6 for acid fermentation treatment, or an alkaline solution is added to maintain the pH value of the leachate at 8-9 for alkaline fermentation treatment, to generate small molecule organic acids. s6, the sludge produced by the biological reaction is discharged from the reaction tank into the return sludge tank; s7. Use a sludge concentration meter to monitor the MLSS concentration in the reaction tank, return part of the sludge in the return sludge tank to the reaction tank, and discharge the remaining sludge into the sludge storage tank. s8, after the sludge settles in the reaction tank, an organic liquid biomass carbon source containing small molecule organic acids is obtained and pumped into the carbon source finished product silo for storage. S9 transports organic liquid biomass carbon sources from the finished carbon source warehouse to the carbon source addition point of the wastewater treatment equipment.

[0018] The alkaline solution is a NaOH solution. The acidic solution is... Solution. Alkali fermentation is the optimal treatment method for anaerobic bacteria to process macromolecular organic matter.

[0019] The acid fermentation treatment includes a hydrolysis stage, an acidification stage, and a volatile organic acid (VFA) production stage. In the hydrolysis stage, hydrolytic fermentation bacteria decompose macromolecular organic matter, controlling the pH of the leachate to 6.5-7.5 and the retention time (HRT) to 1-3 days. In the acidification stage, acid-producing bacteria convert the hydrolysis products into bioavailable organic acids, controlling the pH of the leachate to 5.0-6.0 and the HRT to 1-2 days. In the VFA production stage, hydrogen-producing acetic acid bacteria convert organic acids into acetic acid, propionic acid, butyric acid, and valeric acid, controlling the pH of the leachate to 5.0-6.0 and the HRT to 1-2 days. The difference between the alkaline fermentation treatment and the acid fermentation treatment is that the pH of the acidification and VFA production stages is controlled at 8.0-9.0.

[0020] The hydrolysis stage includes low-temperature fermentation and mesophilic fermentation. Low-temperature fermentation controls the leachate temperature at 10-20℃, while mesophilic fermentation controls it at 20-40℃. A variable-frequency stirrer is installed inside the reaction vessel, and its rotation speed is 30-45 r / min during the hydrolysis-acidification treatment. During the hydrolysis-acidification treatment, the MLSS concentration in the reaction vessel is less than 10 g / L.

[0021] Example 1: Results of acid fermentation treatment.

[0022] COD mg / L BOD mg / L Suspended solids (SS) mg / L ammonia nitrogen mg / L Total phosphorus mg / L Total nitrogen mg / L Total acid mg / L Sample injection 27210.75 11937.79 4218.15 792.32 36.39 1179.16 7188.09 Sample 23134.05 15080.62 1316.33 742.71 33.68 1083.69 17368.81

[0023] Example 2: Results of alkaline fermentation treatment.

[0024] The initial COD of the high-concentration organic leachate to be treated was 40832.17 mg / L, BOD5 was 17171.48 mg / L, suspended solids (SS) was 3698.42 mg / L, ammonia nitrogen was 795.32 mg / L, total phosphorus was 495.54 mg / L, total nitrogen was 1089.34 mg / L, and VFAs were 13858.94 mg / L.

[0025] COD mg / L BOD mg / L Suspended solids (SS) mg / L ammonia nitrogen mg / L Total phosphorus mg / L Total nitrogen mg / L Total acid mg / L Sample injection 40832.17 17171.48 3698.42 795.32 495.54 1089.34 13858.94 Sample 35599.42 22071.64 1722.75 723.73 475.06 1044.2 31395.17

[0026] This production system, through the coordinated use of a bar screen, equalization tank, sludge tank, reaction tank, return sludge tank, sludge storage tank, and carbon source finished product silo, performs biological anaerobic treatment on the collected landfill leachate. During the treatment, not only are large-particle impurities and fibers from the leachate discharged as sludge, but large-molecule organic matter is also fermented to obtain small-molecule organic acids, which are then converted into acetic acid, propionic acid, etc. This differs from existing methods for treating organic waste liquids from domestic sources such as kitchen waste and food scraps. It processes leachate from landfill transfer stations, which has a lower COD concentration and more complex composition, to obtain a leachate biomass carbon source that can replace commercial carbon sources. This resource-based utilization of landfill leachate that would otherwise be sent to a wastewater treatment plant achieves high-value, low-carbon resource utilization of wastewater and synergistic effects of pollution reduction and carbon reduction.

[0027] By controlling the MLSS concentration of leachate during fermentation to be much lower than that of traditional fermentation processes (20-40 g / L), fermentation can be carried out under both acidic and alkaline conditions, efficiently producing biomass carbon sources. While ensuring a low COD loss rate, hydrogen-producing and acetic acid-producing bacteria are used to convert organic acids into acetic acid, propionic acid, etc., thereby improving the conversion rate of VFAs that can be directly used for wastewater treatment. This transforms leachate from waste transfer stations, which originally had poor biodegradability (i.e., a low B / C ratio), into a high-quality biomass carbon source with better biodegradability and a higher B / C ratio.

Claims

1. A biomass carbon source production system using leachate from a landfill transfer station, characterized in that: The process includes a bar screen, equalization tank, sludge tank, reaction tank, return sludge tank, sludge storage tank, and carbon source finished product silo. The carbon source production process includes... s1 collects leachate from the waste transfer station and feeds it into a bar screen, where the bar screens intercept large-diameter impurities and fibers in the leachate. s2, after intercepting impurities, the leachate is pumped from the bar screen into the equalization tank, and then an alkaline solution is introduced into the equalization tank to adjust the pH value of the leachate to 8-9, so that heavy metals in the leachate are precipitated and removed. s3, the sediment in the regulating tank is filtered, and the filtered sediment is transported to the sludge tank for sludge discharge treatment; s4, the filtered leachate is pumped from the regulating tank into the reaction tank, and anaerobic bacteria are inoculated in the reaction tank to hydrolyze and acidify the macromolecular organic matter in the leachate. s5. The pH value in the reaction tank is monitored by a pH sensor. By adding an acidic solution, the pH value of the leachate is maintained at 5-6 for acid fermentation treatment, or an alkaline solution is added to maintain the pH value of the leachate at 8-9 for alkaline fermentation treatment, to generate small molecule organic acids. s6, the sludge produced by the biological reaction is discharged from the reaction tank into the return sludge tank; s7. Use a sludge concentration meter to monitor the MLSS concentration in the reaction tank, return part of the sludge in the return sludge tank to the reaction tank, and discharge the remaining sludge into the sludge storage tank. s8, after the sludge settles in the reaction tank, an organic liquid biomass carbon source containing small molecule organic acids is obtained and pumped into the carbon source finished product silo for storage. S9 transports organic liquid biomass carbon sources from the finished carbon source warehouse to the carbon source addition point of the wastewater treatment equipment.

2. The biomass carbon source production system using leachate from a landfill transfer station according to claim 1, characterized in that: The alkaline solution is a NaOH solution.

3. The biomass carbon source production system using leachate from a landfill transfer station according to claim 1, characterized in that: The acidic solution is Solution.

4. The biomass carbon source production system using leachate from a landfill transfer station according to claim 1, characterized in that: Alkali fermentation is the optimal treatment method for anaerobic bacteria to process macromolecular organic matter.

5. A biomass carbon source production system using leachate from a landfill transfer station according to claim 1, characterized in that: The acid fermentation treatment includes a hydrolysis stage, an acidification stage, and a volatile organic acid (VFA) production stage. In the hydrolysis stage, hydrolytic fermentation bacteria decompose macromolecular organic matter, controlling the pH of the leachate to 6.5-7.5 and the retention time (HRT) to 1-3 days. In the acidification stage, acid-producing bacteria convert the hydrolysis products into bioavailable organic acids, controlling the pH of the leachate to 5.0-6.0 and the HRT to 1-2 days. In the VFA production stage, hydrogen-producing acetic acid bacteria convert organic acids into acetic acid, propionic acid, butyric acid, and valeric acid, controlling the pH of the leachate to 5.0-6.0 and the HRT to 1-2 days. The difference between the alkaline fermentation treatment and the acid fermentation treatment is that the pH of the acidification and VFA production stages is controlled at 8.0-9.

0.

6. The biomass carbon source production system using leachate from a landfill transfer station according to claim 5, characterized in that: The hydrolysis stage includes low-temperature fermentation and mesophilic fermentation. Low-temperature fermentation controls the temperature of the leachate at 10-20℃, while mesophilic fermentation controls the temperature of the leachate at 20-40℃.

7. The biomass carbon source production system using leachate from a landfill transfer station according to claim 1, characterized in that: The reaction vessel is equipped with a variable frequency stirrer, which rotates at 30-45 r / min during the hydrolysis and acidification process.

8. The biomass carbon source production system using leachate from a landfill transfer station according to claim 1, characterized in that: During the hydrolysis and acidification treatment, the MLSS concentration in the reaction vessel is less than 10 g / L.

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