Method for pretreating white spirit wastewater by utilizing magnesium-carbon primary battery principle

Abstract

The invention relates to the technical field of treatment of high-concentration difficult-to-treat organic wastewater, and discloses a method for pretreating white spirit wastewater by utilizing a magnesium-carbon primary battery principle, which comprises the following steps: S1, introducing the white spirit wastewater into a reaction tank through a water inlet pipe; s2, in the primary battery, a negative plate magnesium plate is subjected to an oxidation reaction to generate magnesium ions, a positive plate carbon plate is subjected to a reduction reaction, part of hydrogen ions in the wastewater are consumed, and hydrogen is generated; s3, the magnesium ions react with ammonia nitrogen (NH) and phosphate (HnPO) in the white spirit wastewater; s4, scraping the magnesium ammonium phosphate precipitate to a sludge deposition hopper through a sludge scraper, and regularly discharging the magnesium ammonium phosphate precipitate; and S5, enabling the treated white spirit wastewater to flow out of the reaction tank through a water outlet pipe, and entering a subsequent treatment process. The magnesium plate and the carbon plate form a primary battery, the reaction is driven by the electrolyte of the white spirit wastewater, the magnesium plate is oxidized to generate magnesium ions, the carbon plate reduces H to generate hydrogen, and an external power supply or mechanical stirring is not needed.

Description

Technical Field

[0001] The invention relates to the technical field of high-concentration difficult-to-treat organic wastewater treatment, and specifically to a method for pretreating liquor wastewater by utilizing the magnesium-carbon primary battery principle. Background Art

[0002] Liquor wastewater is a high-concentration, difficult-to-treat organic wastewater, which mainly comes from flushing water and bottom water generated during the liquor brewing process. Its water quality characteristics are complex, with strong acidity, high ammonia nitrogen, high phosphate, high COD and high hardness. The pH value of typical liquor wastewater is between 4-5, the ammonia nitrogen content is ≤400mg / L, the total nitrogen content is ≤500mg / L, the total phosphorus content is ≤350mg / L, and the chemical oxygen demand (COD) is ≤25000mg / L. Due to its high ammonia nitrogen and high phosphate components, in conventional wastewater treatment processes, especially in the anaerobic treatment stage, large particles of inorganic matter are easily generated, which seriously affects the sludge activity of the anaerobic system, resulting in sludge floating and reduced activity. At the same time, high concentrations of ammonia nitrogen and phosphate significantly increase the nitrification and denitrification loads of the subsequent biochemical system, increase the demand for aeration air volume, and increase the dosage of reagents in the deep treatment stage, resulting in high overall treatment costs.

[0003] In the prior art, the pretreatment of liquor wastewater usually adopts a process of flocculation and sedimentation combined with flotation to remove sediment and scum in the wastewater. For example, by adding flocculants (such as polyaluminium chloride or polyacrylamide) for precipitation, the suspended matter is separated by flotation equipment. However, the process has limited removal effect on ammonia nitrogen and phosphate, resulting in a high concentration of ammonia nitrogen and phosphate in the wastewater entering the anaerobic system. In an anaerobic environment, phosphate and ammonia nitrogen easily react with magnesium ions in the wastewater to form crystals such as magnesium ammonium sulfate (MgNH4SO4), which are deposited on the inner wall of the anaerobic tank and the surface of the equipment, causing serious scaling, sludge calcification and decreased activity. The formation of these crystals not only reduces the treatment efficiency of the anaerobic system, but also has an adverse effect on the operation of the subsequent aerobic-anoxic (AO) system, such as excessive biochemical load and difficulty in sludge treatment. In addition, the existing pretreatment process usually requires greater power support (such as stirring and operation of flotation equipment), high energy consumption, and further increases the treatment cost.

[0004] In view of the high ammonia nitrogen and high phosphate characteristics of liquor wastewater, some studies have attempted to introduce chemical precipitation in the pretreatment stage, by adding magnesium salts (such as MgCl2) to react with ammonia nitrogen and phosphate to generate magnesium ammonium phosphate (MgNH4PO4·6H2O) precipitation to reduce the concentration of pollutants. However, this method requires additional addition of chemicals, which increases the cost of chemicals, and fails to effectively utilize the characteristics of the wastewater itself. The treatment process still requires power equipment support, and it is difficult to achieve a combination of low cost and high efficiency. It relies on external power and chemicals, and has high energy consumption and operating costs. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for pretreating liquor wastewater using the principle of magnesium-carbon primary cells, which solves the problem that the prior art treatment process relies on external power and chemicals, and has high energy consumption and operating costs.

[0006] To achieve the above purpose, the present invention is implemented by the following technical scheme: a method for pretreating liquor wastewater using the principle of magnesium-carbon primary battery, comprising the following steps: S1, introducing liquor wastewater into a reaction tank through a water inlet pipe, wherein a negative electrode magnesium plate and a positive electrode carbon plate are arranged in the reaction tank, wherein the negative electrode magnesium plate and the positive electrode carbon plate are connected by a wire, and the liquor wastewater is used as an electrolyte salt bridge to form a primary battery; S2. In the primary battery, the negative electrode magnesium plate undergoes an oxidation reaction: Mg-2e⁻=Mg²⁺, generating magnesium ions, and the positive electrode carbon plate undergoes a reduction reaction: 2H⁺+2e⁻=H2, consuming part of the hydrogen ions in the wastewater and generating hydrogen; S3, the magnesium ions react with ammonia nitrogen and phosphate in the liquor wastewater to form insoluble magnesium ammonium phosphate precipitate: Mg²⁺+NH4⁺+H n PO4³⁻ⁿ+6H2O=MgNH4PO4·6H2O↓+nH⁺ (n=0-2); S4, scraping the magnesium ammonium phosphate precipitate to the mud bucket by a scraper and discharging it regularly, while using the hydrogen bubbles to drive the scum to rise, scraping the scum to the slag discharge tank by the scraper, and discharging it through the slag discharge pipe; S5. The treated liquor wastewater flows out of the reaction tank through the outlet pipe and enters the subsequent treatment process.

[0007] Preferably, the negative electrode magnesium plate and the positive electrode carbon plate in the reaction tank are evenly spaced, and according to the concentration of ammonia nitrogen and phosphate in the liquor wastewater, the reaction tank is arranged in multiple stages in series.

[0008] Preferably, the multi-stage series connection is set to 3 stages in series.

[0009] Preferably, according to the amount of liquor wastewater, the plurality of reaction tanks are operated in parallel.

[0010] Preferably, the overall process flow of the method includes: the liquor wastewater passes through a mechanical screen, a regulating tank, a magnesium-carbon primary battery reaction tank, an alkali-added high-efficiency flocculation sedimentation tank, a flotation tank, a hydrolysis acidification tank, an anaerobic reactor, a two-stage AO reaction tank, a secondary sedimentation tank and a deep treatment system in sequence, wherein the magnesium-carbon primary battery reaction tank is arranged after the regulating tank and before the alkali-added high-efficiency flocculation sedimentation tank.

[0011] Preferably, the pH value of the liquor wastewater is 4-5, the ammonia nitrogen content is ≤400 mg / L, the total nitrogen content is ≤500 mg / L, and the total phosphorus content is ≤350 mg / L.

[0012] Preferably, the scraper has a scraping mud condition and a scraping slag condition in the reaction tank, wherein in the scraping mud condition, the sediment is scraped into the mud hopper, and in the scraping slag condition, the slag is scraped into the slag discharge tank.

[0013] Preferably, the method does not require an external power device and is carried out spontaneously using the primary cell reaction.

[0014] Preferably, a magnesium-carbon primary battery reaction pool comprises a reaction tank, a water inlet pipe is arranged inside the left side of the reaction tank, a water outlet pipe is arranged inside the right side of the reaction tank, a slag discharge tank one and a slag discharge tank two are opened inside the upper side of the reaction tank, a negative electrode magnesium plate and a positive electrode carbon plate are arranged inside the reaction tank, a mud scraper is arranged inside the reaction tank, and a mud bucket is fixedly connected to the bottom end of the water inlet pipe.

[0015] Preferably, the negative electrode magnesium plate and the positive electrode carbon plate are both arranged in a reaction tank, and are connected by a wire to form a primary battery.

[0016] The present invention provides a method for pretreating liquor wastewater using the principle of magnesium-carbon primary battery. It has the following beneficial effects: 1. The present invention utilizes magnesium plates and carbon plates to form a primary battery. The reaction is driven by the electrolyte of liquor wastewater itself. The magnesium plates are oxidized to generate magnesium ions, and the carbon plates reduce H⁺ to generate hydrogen. No external power supply or mechanical stirring is required. Compared with the traditional flocculation sedimentation + flotation process, about 0.5-1 kWh of electricity can be saved for every 1 m³ of wastewater treated. For a winery that treats 100,000 m³ of wastewater annually, 50,000-100,000 kWh of electricity can be saved, reducing the operating cost by about 10-15%.

[0017] 2. The present invention uses magnesium-carbon primary battery reaction, the negative electrode generates Mg²⁺ and NH4⁺ and PO4³⁻ to generate magnesium ammonium phosphate precipitation, and the positive electrode consumes H⁺ to generate hydrogen, thereby achieving the simultaneous removal of acidity, ammonia nitrogen and phosphate. Taking wastewater with 350mg / L ammonia nitrogen and 300mg / L phosphate as an example, after treatment, the ammonia nitrogen is reduced to about 120mg / L (removal rate 65%), the phosphate is reduced to about 90mg / L (removal rate 70%), and the pH is increased from 4.5 to 5.5, which reduces the load of the subsequent anaerobic system by about 20%, avoids sludge floating and activity decline, and reduces the nitrification and denitrification burden of the AO system by about 15-20%, reducing aeration energy consumption.

[0018] 3. The magnesium ammonium phosphate precipitate generated by the present invention can absorb calcium and magnesium ions in wastewater and reduce the hardness of the water body. Taking the treatment of liquor wastewater with high hardness as an example, the calcium and magnesium ion content is reduced by about 30-40% after pretreatment, and the scaling tendency of the anaerobic system and the subsequent biochemical system is reduced by about 30-50%. Compared with the situation in which equipment scaling is serious and frequent maintenance is required in traditional processes, this method extends the equipment maintenance cycle by about 1.5 times, reduces downtime for cleaning, and improves operational stability.

[0019] 4. The present invention utilizes the carbon plate positive electrode reaction 2H⁺+2e⁻=H2 to consume hydrogen ions in the wastewater, thereby raising the pH from 4.5 to about 5.5. Taking the daily treatment of 50m³ of wastewater as an example, the amount of NaOH used in the subsequent alkaline flocculation sedimentation tank after pretreatment is reduced by about 20-30%, and the cost of alkali agent is saved by about 0.5-1 yuan per ton of wastewater. This not only reduces the investment in chemical agents, but also reduces the risk of corrosion to subsequent equipment (such as anaerobic tanks) due to high acidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an overall process flow chart of a method for pretreating liquor wastewater using the magnesium-carbon primary battery principle of the present invention; Figure 2 This is a partial structural diagram of a water inlet pipe of a magnesium-carbon primary battery reaction tank of the present invention; Figure 3 It is a schematic diagram of the partial structure of a positive electrode carbon plate of a magnesium-carbon primary battery reaction cell of the present invention; Figure 4 It is a schematic diagram of the partial structure of a scraper for a magnesium-carbon primary battery reaction tank of the present invention; Figure 5 The present invention is a partial structural schematic diagram of a slag discharge trough of a magnesium-carbon primary battery reaction cell.

[0021] Among them, 1. water inlet pipe; 2. reaction tank; 3. negative electrode magnesium plate; 4. positive electrode carbon plate; 5. slag discharge trough 1; 6. water outlet pipe; 7. slag discharge trough 2; 8. mud scraper; 9. mud bucket. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0023] Please see attached Figure 1 -Attached Figure 5 The embodiment of the present invention provides a method for pretreating liquor wastewater using the principle of magnesium-carbon primary battery, comprising the following steps: S1, introducing liquor wastewater into a reaction tank 2 through a water inlet pipe 1, wherein a negative electrode magnesium plate 3 and a positive electrode carbon plate 4 are arranged in the reaction tank 2, wherein the negative electrode magnesium plate 3 and the positive electrode carbon plate 4 are connected by a wire, and the liquor wastewater is used as an electrolyte salt bridge to form a primary battery; S2. In the primary battery, the negative electrode magnesium plate 3 undergoes an oxidation reaction: Mg-2e⁻=Mg²⁺, generating magnesium ions, and the positive electrode carbon plate 4 undergoes a reduction reaction: 2H⁺+2e⁻=H2, consuming part of the hydrogen ions in the wastewater and generating hydrogen; S3, magnesium ions and ammonia nitrogen (NH4⁺) and phosphate (H n PO4³⁻ⁿ) to form an insoluble magnesium ammonium phosphate precipitate: Mg²⁺+NH4⁺+H n PO4³⁻ⁿ+6H2O=MgNH4PO4·6H2O↓+nH⁺ (n=0-2); S4, scrape the magnesium ammonium phosphate precipitate to the mud bucket 9 through the scraper 8 and discharge it regularly, and use the hydrogen bubbles to drive the scum to rise, and scrape the scum to the slag discharge tank 5 through the scraper 8, and discharge it through the slag discharge pipe 7; S5. The treated liquor wastewater flows out of the reaction tank 2 through the outlet pipe 6 and enters the subsequent treatment process.

[0024] Specifically, a rectangular reaction tank 2 with a length of 2m, a width of 1m, and a height of 1.5m is selected, and the material is corrosion-resistant stainless steel. Ten magnesium metal plates with a specification of 1m×0.8m×0.01m are installed in the reaction tank 2 as the negative plate magnesium plate 3 and 10 carbon plates of the same specification as the positive plate carbon plate 4. The magnesium plates and carbon plates are evenly distributed with a spacing of 5cm and connected by copper wires to form a primary battery. Liquor wastewater (pH4.5, ammonia nitrogen 350mg / L, phosphate 300mg / L) is introduced into the reaction tank 2 at a flow rate of 2m³ / h through a water inlet pipe 1 with a diameter of 50mm. During the reaction, the magnesium plate 3 is oxidized to generate Mg²⁺, the carbon plate 4 reduces H⁺ to produce hydrogen, and Mg²⁺ reacts with NH4⁺ and PO4³⁻ to generate magnesium ammonium phosphate precipitation. The precipitate is scraped to the conical sludge bucket 9 once every 12 hours by the chain scraper 8 installed at the bottom of the reaction tank. A valve is provided at the bottom of the sludge bucket 9 to discharge the sludge once every 24 hours. The hydrogen bubbles drive the scum to rise. When the scraper 8 turns to the upper part, the scum is scraped to the slag discharge tank 5 every 6 hours and discharged through the slag discharge pipe 7 with a diameter of 30 mm. The treated wastewater flows into the alkali flocculation sedimentation tank through the outlet pipe 6.

[0025] No-power operation, energy-saving and environmental protection: Utilizing the principle of primary battery for spontaneous reaction, no external power supply is required, saving electricity costs, and saving about 0.5-1kWh of electricity for every 1m³ of wastewater treated.

[0026] The negative electrode magnesium plate 3 and the positive electrode carbon plate 4 in the reaction tank 2 are evenly spaced and distributed, and according to the concentration of ammonia nitrogen and phosphate in the liquor wastewater, the reaction tank 2 is arranged in multiple stages in series.

[0027] Specifically, for high-concentration liquor wastewater with an ammonia nitrogen concentration of 400 mg / L and a phosphate concentration of 350 mg / L, three reaction tanks 2 are arranged in series, and the specifications of each tank are the same as those described in claim 1, with a length of 2m, a width of 1m, and a height of 1.5m. Ten magnesium plates 3 and ten carbon plates 4 are arranged in each reaction tank, evenly distributed at intervals of 5cm, and the magnesium plates and carbon plates are connected by copper wires. Liquor wastewater enters from the water inlet pipe 1 of the first reaction tank at a flow rate of 1.5m³ / h, and flows through the second and third reaction tanks in turn. The outlet pipes 6 of each tank are connected to the water inlet pipe 1 of the next level through a pipeline. Each reaction tank is equipped with a scraper 8, a mud bucket 9 and a slag discharge tank 5. The sedimentation and scum treatment method is the same as that of claim 1. The residence time of each reaction tank is about 1 hour, and the total treatment time is 3 hours, ensuring the efficient removal of ammonia nitrogen and phosphate.

[0028] Through three-stage cascade reactions, ammonia nitrogen in wastewater is reduced from 400 mg / L to 100 mg / L, phosphate is reduced from 350 mg / L to 80 mg / L, and pH is increased to 6.0, effectively reducing the subsequent alkali addition amount by about 30-40% and the biochemical system load by about 25%, reducing the scaling tendency by about 50%, and significantly improving the pretreatment effect of high-concentration wastewater.

[0029] The multi-stage series connection is set to 3 stages in series.

[0030] Specifically, a three-stage series reaction tank 2 is selected to treat liquor wastewater with 380 mg / L of ammonia nitrogen and 320 mg / L of phosphate. The specifications of each stage of the reaction tank are 2 m long, 1 m wide and 1.5 m high, and 10 magnesium plates (3) and 10 carbon plates 4 are arranged inside, with a spacing of 5 cm, and connected by wires to form a primary cell. The wastewater enters from the first-stage water inlet pipe 1 at a flow rate of 1.5 m³ / h, and flows through the second and third stages in sequence. The first-stage water outlet pipe 6 is connected to the second-stage water inlet pipe 1, and the second-stage water outlet pipe is connected to the third-stage water inlet pipe. Each stage is equipped with a scraper 8, which scrapes the mud to the mud bucket 9 every 12 hours, and scrapes the scum to the slag discharge tank 5 every 6 hours. The third-stage water outlet pipe 6 discharges the treated wastewater, and the ammonia nitrogen is reduced to about 150 mg / L, and the phosphate is reduced to about 100 mg / L.

[0031] The fixed three-stage series design increases the pH of wastewater from 4.5 to 5.8, and the removal rates of ammonia nitrogen and phosphate reach 60% and 69% respectively, reducing the amount of alkali added by about 25-35%, reducing the scaling of the anaerobic system by about 40% and the biochemical load by about 20%, providing stable and efficient pretreatment for medium-concentration wastewater.

[0032] According to the amount of liquor wastewater, multiple reaction tanks 2 are operated in parallel.

[0033] Specifically, for the large amount of liquor wastewater with a daily processing capacity of 50m³, 5 reaction tanks 2 are selected for parallel operation. The specifications of each tank are 2m long, 1m wide and 1.5m high. There are 10 magnesium plates 3 and 10 carbon plates 4 inside, which are 5cm apart and connected by wires. The wastewater is evenly distributed from the main water inlet pipe to the water inlet pipe 1 of each reaction tank at a flow rate of 10m³ / h through the diversion pipe, and each reaction tank processes 2m³ / h. Each reaction tank is equipped with a scraper 8, a mud bucket 9 and a slag discharge tank 5. The sediment is scraped to the mud bucket 9 every 12 hours, and the slag is scraped to the slag discharge tank 5 every 6 hours. The outlet pipes 6 of each tank are collected to the main outlet pipe for discharge, ensuring the efficient treatment of large amounts of wastewater.

[0034] Parallel operation reduces ammonia nitrogen from 350mg / L to 120mg / L, phosphate from 300mg / L to 90mg / L, pH to 5.5, reduces alkali addition by about 20-30% and biochemical load by about 20%, reduces scaling risk by about 30%, saves about 0.5-1kWh of electricity per m³ of wastewater, and efficiently adapts to large water treatment needs.

[0035] The overall process flow of the method includes: the liquor wastewater passes through a mechanical screen, a regulating tank, a magnesium-carbon primary battery reaction tank, an alkali-added high-efficiency flocculation sedimentation tank, a flotation tank, a hydrolysis acidification tank, an anaerobic reactor, a two-stage AO reaction tank, a secondary sedimentation tank and a deep treatment system in sequence, wherein the magnesium-carbon primary battery reaction tank is arranged after the regulating tank and before the alkali-added high-efficiency flocculation sedimentation tank.

[0036] Specifically, liquor wastewater (pH 4.5, ammonia nitrogen 350mg / L, phosphate 300mg / L) first passes through a mechanical grid with an aperture of 10mm to remove large particle impurities, and enters a regulating tank with a volume of 20m³ for homogenization for 48 hours. Then it enters the magnesium-carbon primary battery reaction tank, which has a length of 2m, a width of 1m, and a height of 1.5m. It is equipped with 10 magnesium plates 3 and 10 carbon plates 4, and is treated at a flow rate of 2m³ / h, with a residence time of 1 hour. The precipitation and scum treatment are the same as claim 1. The effluent enters the alkali-added high-efficiency flocculation sedimentation tank, adds NaOH to adjust the pH to 7-8, adds PAM flocculant for precipitation for 30 minutes, and then removes the scum through the flotation tank. After that, it enters the hydrolysis acidification tank (staying for 12 hours), the anaerobic reactor (staying for 24 hours), the two-stage AO reaction tank (staying for 12 hours at each stage), the secondary sedimentation tank (staying for 4 hours), and finally passes through the deep treatment system to meet the discharge standards.

[0037] The reaction tank reduces ammonia nitrogen to 120 mg / L, phosphate to 90 mg / L, pH to 5.5, reduces the amount of alkali added by about 20-30%, reduces anaerobic system sludge calcification by about 40% and AO system load by about 20%, reduces the amount of phosphorus removal agents used by about 30%, and improves the economy and stability of the overall process.

[0038] The pH value of liquor wastewater is 4-5, the ammonia nitrogen content is ≤400mg / L, the total nitrogen content is ≤500mg / L, and the total phosphorus content is ≤350mg / L.

[0039] Specifically, the treated liquor wastewater has a pH of 4.5, ammonia nitrogen 350mg / L, total nitrogen 450mg / L, phosphate 300mg / L, and COD 20000mg / L. The specifications of the reaction tank 2 are 2m long, 1m wide, and 1.5m high. There are 10 magnesium plates 3 and 10 carbon plates 4 with a spacing of 5cm. The wastewater enters at a flow rate of 2m³ / h and stays for 1 hour. The reaction generates magnesium ammonium phosphate precipitation. The scraper 8 scrapes the mud to the mud bucket 9 every 12 hours, and scrapes the scum to the slag discharge tank 5 every 6 hours. After treatment, the ammonia nitrogen in the wastewater drops to about 120mg / L, the phosphate drops to about 90mg / L, the pH rises to about 5.5, and the COD drops slightly to 18000mg / L, and enters the subsequent process.

[0040] For specific water quality, the method reduces ammonia nitrogen to 120mg / L, phosphate to 90mg / L, pH to 5.5, reduces the amount of alkali added by about 20-30% and the biochemical load by about 20%, reduces the risk of scaling by about 30%, saves about 0.5-1kWh / m³ of electricity without power operation, and effectively solves the problem of high ammonia nitrogen and high phosphorus.

[0041] The scraper 8 has a scraping mud working state and a scraping slag working state in the reaction tank 2 , wherein in the scraping mud working state, the sediment is scraped to the mud hopper 9 , and in the scraping slag working state, the slag is scraped to the slag discharge tank 5 .

[0042] Specifically, the reaction tank 2 is 2m long, 1m wide and 1.5m high, and is equipped with 10 magnesium plates 3 and 10 carbon plates 4. The wastewater is treated at a flow rate of 2m³ / h. The scraper 8 is a chain structure, equipped with a two-way scraper, and the scraper is 2m long and 0.2m wide. Under the scraping condition, the scraper is located at the bottom of the tank and runs along the bottom once every 12 hours to scrape the magnesium ammonium phosphate precipitate to the mud bucket 9; under the scraping condition, the scraper flips to the upper part of the tank and runs once every 6 hours to scrape the scum to the slag discharge tank 5. The sludge hopper 9 discharges the sludge once every 24 hours, and the slag discharge pipe 7 discharges the slag.

[0043] The scraper's dual-mode operation can efficiently separate sediment and scum, reducing ammonia nitrogen from 350mg / L to 120mg / L, phosphate from 300mg / L to 90mg / L, pH value to 5.5, reducing the amount of alkali added by about 20-30% and the scaling risk by about 30%, and improving the operating stability of the reaction tank and the solid-liquid separation efficiency by about 50%.

[0044] The method does not require an external power device and utilizes the spontaneous reaction of the primary cell.

[0045] Specifically, the specifications of the reaction tank 2 are 2m long, 1m wide and 1.5m high, and there are 10 magnesium plates 3 and 10 carbon plates 4 inside, which are connected by copper wires and spontaneously form a primary cell using wastewater electrolyte. Wastewater (ammonia nitrogen 350mg / L, phosphate 300mg / L) enters at a flow rate of 2m³ / h and stays for 1 hour. The magnesium plate is oxidized to generate Mg²⁺, and the carbon plate reduces H⁺ to produce hydrogen, without the need for external power supply or mechanical stirring. The precipitation and scum treatment is the same as claim 1, and is completed spontaneously by the primary cell reaction. After 24 hours of operation, the ammonia nitrogen is reduced to about 130mg / L and the phosphate is reduced to about 95mg / L.

[0046] The unpowered reaction raises the pH of wastewater from 4.5 to 5.5, and the removal rates of ammonia nitrogen and phosphate reach 63% and 68% respectively, reducing the amount of alkali added by about 20-30% and the biochemical load by about 20%, reducing scaling by about 30%, and saving about 0.5-1kWh of electricity per m³, taking into account both energy saving and efficient treatment.

[0047] Please see attached Figure 2 -Attached Figure 5 A magnesium-carbon primary battery reaction cell comprises a reaction tank 2, a water inlet pipe 1 is arranged inside the left side of the reaction tank 2, a water outlet pipe 6 is arranged inside the right side of the reaction tank 2, a slag discharge tank 1 5 and a slag discharge tank 2 7 are opened inside the upper side of the reaction tank 2, a negative electrode magnesium plate 3 and a positive electrode carbon plate 4 are arranged inside the reaction tank 2, a scraper 8 is arranged inside the reaction tank 2, and a mud bucket 9 is fixedly connected to the bottom end of the water inlet pipe 1.

[0048] The negative electrode magnesium plate 3 and the positive electrode carbon plate 4 are both arranged in the reaction tank 2, and are connected by a wire to form a primary battery.

[0049] Specifically, during actual installation, the diameter of the water inlet pipe 1 is reasonably selected according to the input flow rate of the liquor wastewater to ensure that the wastewater can flow into the reaction tank 2 stably and smoothly. The diameter of the water outlet pipe 6 also needs to be determined based on the discharge requirements of the treated wastewater to ensure that the treated wastewater can be discharged in time to avoid accumulation in the reaction tank 2. The reaction tank 2 is made of polyurethane-coated stainless steel to extend the service life of the reaction tank 2. The arrangement of the negative electrode magnesium plate 3 and the positive electrode carbon plate 4 in the reaction tank 2 should ensure uniform spacing, so that the primary battery reaction can be more sufficient and stable, and the reaction efficiency is improved.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for pretreating liquor wastewater using the principle of magnesium-carbon primary cells, characterized in that: The following steps are involved: S1, introducing liquor wastewater into a reaction tank (2) through a water inlet pipe (1), wherein a negative electrode magnesium plate (3) and a positive electrode carbon plate (4) are arranged in the reaction tank (2), wherein the negative electrode magnesium plate (3) and the positive electrode carbon plate (4) are connected by a wire, and the liquor wastewater is used as an electrolyte salt bridge to form a primary battery; S2. In the primary battery, the negative electrode magnesium plate (3) undergoes an oxidation reaction: Mg-2e⁻=Mg²⁺, generating magnesium ions, and the positive electrode carbon plate (4) undergoes a reduction reaction: 2H⁺+2e⁻=H2, consuming part of the hydrogen ions in the wastewater and generating hydrogen; S3, the magnesium ions react with ammonia nitrogen and phosphate in the liquor wastewater to form insoluble magnesium ammonium phosphate precipitate: Mg²⁺+NH4⁺+H n PO4³⁻ⁿ+6H2O=MgNH4PO4·6H2O↓+nH⁺ (n=0-2); S4, scraping the magnesium ammonium phosphate precipitate to a sludge bucket (9) by a sludge scraper (8) and discharging it regularly, while using the hydrogen bubbles to drive the slag to rise, scraping the slag to a slag discharge tank (5) by the sludge scraper (8), and discharging it through a slag discharge pipe (7); S5. The treated liquor wastewater flows out of the reaction tank (2) through the outlet pipe (6) and enters the subsequent treatment process.

2. The method for pretreating liquor wastewater using the magnesium-carbon primary battery principle according to claim 1 is characterized in that: The negative electrode magnesium plate (3) and the positive electrode carbon plate (4) in the reaction tank (2) are evenly spaced and distributed, and according to the concentration of ammonia nitrogen and phosphate in the liquor wastewater, the reaction tank (2) is arranged in multiple stages in series.

3. The method for pretreating liquor wastewater using the magnesium-carbon primary battery principle according to claim 2 is characterized in that: The multi-stage series connection is configured as a three-stage series connection.

4. The method for pretreating liquor wastewater using the magnesium-carbon primary battery principle according to claim 1 is characterized in that: According to the amount of liquor wastewater, a plurality of reaction tanks (2) are operated in parallel.

5. The method for pretreating liquor wastewater using the magnesium-carbon primary battery principle according to claim 1 is characterized in that: The overall process flow of the method includes: the liquor wastewater passes through a mechanical screen, a regulating tank, a magnesium-carbon primary battery reaction tank, an alkali-added high-efficiency flocculation sedimentation tank, a flotation tank, a hydrolysis acidification tank, an anaerobic reactor, a two-stage AO reaction tank, a secondary sedimentation tank and a deep treatment system in sequence, wherein the magnesium-carbon primary battery reaction tank is arranged after the regulating tank and before the alkali-added high-efficiency flocculation sedimentation tank.

6. The method for pretreating liquor wastewater using the magnesium-carbon primary battery principle according to claim 1 is characterized in that: The pH value of the liquor wastewater is 4-5, the ammonia nitrogen content is ≤400 mg / L, the total nitrogen content is ≤500 mg / L, and the total phosphorus content is ≤350 mg / L.

7. The method for pretreating liquor wastewater using the magnesium-carbon primary battery principle according to claim 1 is characterized in that: The scraper (8) has a scraping mud working condition and a scraping slag working condition in the reaction tank (2), wherein in the scraping mud working condition, the sediment is scraped into the mud accumulation bucket (9), and in the scraping slag working condition, the floating slag is scraped into the slag discharge tank (5).

8. The method for pretreating liquor wastewater using the magnesium-carbon primary battery principle according to claim 1 is characterized in that: The method does not require an external power device and is carried out spontaneously by utilizing the galvanic cell reaction.

9. A magnesium-carbon primary battery reaction cell, characterized in that: A method for pretreating liquor wastewater using the principle of a magnesium-carbon primary battery as described in any one of claims 1 to 8, comprising a reaction tank (2), a water inlet pipe (1) being arranged inside the left side of the reaction tank (2), a water outlet pipe (6) being arranged inside the right side of the reaction tank (2), a slag discharge tank 1 (5) and a slag discharge tank 2 (7) being arranged inside the upper side of the reaction tank (2), a negative electrode magnesium plate (3) and a positive electrode carbon plate (4) being arranged inside the reaction tank (2), a sludge scraper (8) being arranged inside the reaction tank (2), and a sludge bucket (9) being fixedly connected to the bottom end of the water inlet pipe (1).

10. A magnesium-carbon primary battery reaction cell according to claim 9, characterized in that: The negative electrode magnesium plate (3) and the positive electrode carbon plate (4) are both arranged in the reaction tank (2), and are connected by a wire to form a primary battery.

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