A device and method for treating high-salinity ammonia-nitrogen-containing wastewater by coupling micro-electrolysis with nitrifying bacteria

Abstract

The present application relates to a kind of micro-electrolysis coupling nitrifying bacteria device and method for treating high-salt ammonia-nitrogen-containing wastewater, device includes aeration tank reactor, the aeration tank reactor includes the aeration structure, filter plate structure and filler layer sequentially arranged from bottom to top, the filler layer is composed of multiple layers of fillers, which are alternately laid from bottom to top in the order of iron-carbon filler, ceramic filler.The present application changes the permeability of nitrifying bacteria cell membrane under the action of micro-electric field formed by iron-carbon filler, enhances the activity of nitrifying bacteria, improves the salt tolerance of nitrifying bacteria, not only shortens the acclimation time of nitrifying bacteria in high-salt ammonia-nitrogen-containing wastewater, but also improves the ability of nitrifying bacteria to treat ammonia-nitrogen in high-salt wastewater.The present application and traditional high-salt ammonia-nitrogen-containing wastewater treatment technology can reduce energy consumption and treatment cost, and is a kind of efficient and clean high-salt ammonia-nitrogen-containing wastewater treatment method.

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering technology and relates to the treatment of high-salt ammonia nitrogen wastewater. Specifically, it relates to an apparatus and method for treating high-salt ammonia nitrogen wastewater by micro-electrolysis coupled with nitrifying bacteria. Background Technology

[0002] Industries such as biopharmaceuticals, chemicals, and new materials generate high-salt, high-ammonia-nitrogen wastewater during production processes. This type of wastewater is generally difficult to treat and has high treatment costs. There is an urgent need for more efficient and cleaner treatment technologies for this type of wastewater.

[0003] Existing technologies for treating high-salt, high-ammonia-nitrogen wastewater include evaporation, reverse osmosis, sodium hypochlorite oxidation, MAP (method aseptic technique), stripping, and biological methods. Among these methods, evaporation and reverse osmosis suffer from high investment and operating costs, and produce secondary byproducts; sodium hypochlorite oxidation requires large amounts of chemicals; MAP requires large amounts of chemicals, produces large amounts of sludge, and easily leads to excessive phosphorus levels in the effluent; stripping has high energy consumption, still results in high ammonia-nitrogen levels in the effluent, and produces secondary byproducts; traditional biological methods utilize the nitrification of nitrifying bacteria to treat ammonia-nitrogen, generally requiring a salt content not exceeding 2.0%. When the salt content exceeds 2.5%, it significantly inhibits the activity of nitrifying bacteria, requiring an acclimatization period of over 40 days, and reducing treatment efficiency by more than 50%. Summary of the Invention

[0004] To overcome the shortcomings of the existing technology, the present invention provides an apparatus and method for treating high-salt ammonia nitrogen-containing wastewater by micro-electrolysis coupled nitrifying bacteria. The present invention not only shortens the acclimatization time of nitrifying bacteria in high-salt ammonia nitrogen-containing wastewater, but also improves the ability of nitrifying bacteria to treat ammonia nitrogen in high-salt wastewater.

[0005] The technical solution adopted in this invention is as follows:

[0006] A device for treating high-salt ammonia-nitrogen wastewater using micro-electrolysis coupled with nitrifying bacteria includes an aeration tank reactor. The aeration tank reactor includes an aeration structure, a filter plate structure, and a packing layer arranged sequentially from bottom to top. The packing layer consists of multiple layers of packing material arranged alternately from bottom to top in the order of iron-carbon packing material and ceramsite packing material.

[0007] Preferably, the aeration tank reactor is a circular or square aeration filter tank, and the aeration tank reactor is equipped with an online dissolved oxygen meter and an online pH meter. The aeration tank reactor has an inlet at the bottom and an outlet at the top.

[0008] Preferably, the ammonia nitrogen volumetric loading rate of the aeration tank reactor is 40–100 g / m³. 3 •d, the surface loading of the aeration tank reactor is 0.1–0.3 m. 3 / m 2 ·h.

[0009] As a preferred option, the iron-carbon filler dosage is 20-30 g / L, the iron-to-carbon mass ratio is 1:2-3, the voltage formed is 0.8-1.2 V, the particle diameter is 1-2 cm, and the height of a single layer of iron-carbon filler is 5-10 cm.

[0010] Preferably, the ceramsite filler has a diameter of 3–5 mm and a specific surface area of ​​5–8 m². 2 / g, the height of each layer of ceramsite packing is 0.5-1.3m, and the total volume is 15-40% of the volume of the aeration tank reactor.

[0011] The present invention also provides a method for treating high-salt ammonia-nitrogen-containing wastewater using micro-electrolysis coupled with nitrifying bacteria, employing the above-mentioned apparatus and comprising the following steps:

[0012] (1) Introduce high-salt wastewater containing ammonia nitrogen, pre-aerate for 24 hours, and then add nitrifying bacteria agent;

[0013] (2) Aeration acclimatization for 10-20 days, during which dissolved oxygen and pH value are controlled;

[0014] (3) Once acclimatization is complete, gradually increase the influent load.

[0015] Preferably, the wastewater contains 2.5-5% sodium chloride and has an ammonia nitrogen concentration of 100-500 mg / L.

[0016] Preferably, the nitrifying bacteria agent is a compound of bacteria from the genera *Nitrosomonas*, *Nitrosococcus*, *Nitrospirillum*, *Nitrobacter*, *Nitrococcus*, and *Nitrocystis*, in powder form, with a bacterial count of 100 × 10⁻⁶. 8 ~200×10 8 CFU / g, dosage 3-5g / L.

[0017] As a preferred method, during the acclimatization process, the aeration rate is adjusted to control the dissolved oxygen content at 2–3 mg / L, and sodium bicarbonate is added to control the pH value at 7.0–7.5.

[0018] Preferably, the biofilm formed on the surface of the ceramsite packing is 0.1–0.2 mm thick, and the ammonia nitrogen concentration in the reactor is 15–35 mg / L or reduced by 80–90%, indicating that the acclimatization is complete.

[0019] The beneficial effects of this invention are as follows:

[0020] This invention alters the permeability of nitrifying bacteria cell membranes under the influence of a micro-electric field generated by iron-carbon packing material, enhancing their activity and salt tolerance. This not only shortens the acclimatization time of nitrifying bacteria in high-salt, ammonia-nitrogen-containing wastewater but also improves their ability to treat ammonia nitrogen in such wastewater. Compared to traditional high-salt, ammonia-nitrogen-containing wastewater treatment technologies, this invention offers lower energy consumption and treatment costs, representing a highly efficient and clean method for treating such wastewater. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the device for treating high-salt ammonia-nitrogen wastewater using micro-electrolysis coupled with nitrifying bacteria according to the present invention;

[0022] Diagram description: 1-Inlet; 2-Aeration structure (aeration pipe and aeration head); 3-Filter plate structure (filter plate and filter head); 4-Iron-carbon packing; 5-Ceramic granule packing; 6-Outlet; 7-Online dissolved oxygen meter; 8-Online pH meter. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below through embodiments. These embodiments are for illustrative purposes only and are not intended to limit the present invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Unless otherwise specified, the experimental methods described in the embodiments are conventional methods; the percentages mentioned are all mass percentages unless otherwise specified; and the reagents and materials mentioned are all commercially available unless otherwise specified.

[0025] Example 1

[0026] A heparin sodium production plant was treating resin adsorption wastewater, with a flow rate of 200 t / d. The wastewater contained 4-4.5% salinity and 100-120 mg / L ammonia nitrogen. The original treatment process was "anaerobic + nitrification filter," but the nitrification filter was ineffective, with an effluent ammonia nitrogen concentration of 85-90 mg / L, indicating very poor removal efficiency. During the rectification process, 5 g / L of nitrifying bacteria were added and cultured for 35 days. The biofilm thickness formed on the surface of the expanded clay pellets was 0.04-0.05 mm, and the effluent ammonia nitrogen concentration was reduced to 70-75 mg / L, showing slight improvement. The average volumetric loading rate for ammonia nitrogen was 25 g / m³. 3 ·d.

[0027] Construct a new aerated filter (aeration tank reactor) according to the present invention.

[0028] Reference Figure 1A device for treating high-salt ammonia-nitrogen wastewater by micro-electrolysis coupled with nitrifying bacteria includes an aeration tank reactor. The aeration tank reactor includes an aeration structure 2, a filter plate structure 3, and a packing layer arranged sequentially from bottom to top. The packing layer consists of multiple layers of packing material arranged alternately from bottom to top in the order of iron-carbon packing material 4 and ceramsite packing material 5.

[0029] The aeration tank reactor is a circular or square aeration filter tank. The aeration tank reactor is equipped with an online dissolved oxygen meter 7 and an online pH meter 8. The bottom of the aeration tank reactor is equipped with an inlet 1 and the top of the aeration tank reactor is equipped with an outlet 6.

[0030] The method for treating high-salt ammonia-nitrogen-containing wastewater using micro-electrolysis coupled with nitrifying bacteria using the above-mentioned device includes the following steps:

[0031] (1) The total volume of the newly built aerated filter tank is 400m³. 3 It adopts two aerated filter tanks connected in series, with each tank measuring 8m×5m×5.6m and an effective filter depth of 5m;

[0032] (2) The iron and carbon addition amount of a single filter is 6t, m(Fe):m(C)=1:3, the voltage formed is 1.0~1.1V, the particle diameter is 1~2cm, and two layers of iron and carbon packing are set, with the height of each layer of iron and carbon packing being 7.5cm.

[0033] The dosage of ceramsite packing for a single-cell filter bed is 80m³. 3 Diameter 3-5mm, specific surface area 5-8m² 2 / g, the height of each layer of ceramsite filler is 1m, and the ceramsite is soaked in water to remove impurities;

[0034] (3) Fill the water to a level of 4.5m, turn on the blower and aeration pipe valve, and pre-aerate for 24 hours;

[0035] The added nitrifying bacteria agent is a compound of bacteria from the genera *Nitrosomonas*, *Nitrococcus*, *Nitrospirillum*, *Nitrobacter*, *Nitrococcus*, and *Nitrocystis*. It is in powder form with a bacterial count of 150 × 10⁻⁶. 8 ~200×10 8 CFU / g, dosage 4g / L;

[0036] (4) The aeration blower is frequency-controlled to control the dissolved oxygen content to 2-3 mg / L, and the metering pump is used to add 10% sodium bicarbonate solution to control the pH value to 7.0-7.5;

[0037] (5) The ammonia nitrogen concentration in the filter bed was measured daily. On the 15th day of acclimatization, the ammonia nitrogen concentration dropped to 20 mg / L, and a uniform biofilm with a thickness of 0.1 to 0.12 mm was formed on the surface of the ceramsite.

[0038] Water intake began on day 16. For the first three days, the intake load was 50% of the design load. From day 4 onwards, full load was applied. Monitoring showed that the effluent ammonia nitrogen concentration was 12–15 mg / L, and the actual average volumetric ammonia nitrogen loading of the filter was 51 g / m³. 3 ·d.

[0039] Example 2

[0040] A pharmaceutical company's fermentation wastewater has a flow rate of 50 tons per day. The original treatment process for this wastewater was "anaerobic + anoxic + aerobic," but the aerobic stage was ineffective, resulting in excessive ammonia nitrogen levels in the effluent. The aerobic tank was subsequently modified. The effluent from the anaerobic stage now contains 2.5–3.0% salinity and 150–200 mg / L ammonia nitrogen.

[0041] The method for treating high-salt ammonia-nitrogen-containing wastewater using micro-electrolysis coupled with nitrifying bacteria using the device described in Example 1 includes the following steps:

[0042] (1) The original aerobic tank had dimensions of 6m × 3m × 5.5m, an effective water depth of 5m, and an effective volume of 90m³. 3 The surface load after conversion to an aerated filter is 0.15m. 3 / m 2 ·h.

[0043] (2) The modified filter bed has an iron and carbon addition of 2.5t, m(Fe):m(C)=1:2, a voltage of 0.9~1.0V, a particle diameter of 1~2cm, and two layers of iron and carbon packing, each layer of iron and carbon packing with a height of 7.0cm.

[0044] The dosage of ceramsite packing in the modified filter bed is 27m³. 3 Diameter 3-5mm, specific surface area 5-8m² 2 / g, the height of each layer of ceramsite filler is 75cm, and the ceramsite is soaked in water to remove impurities.

[0045] (3) Add coagulation and sedimentation to remove suspended solids in anaerobic effluent. Inflate the water to a level of 4.5m, turn on the blower and aeration pipe valve, and pre-aerate for 24 hours.

[0046] The added nitrifying bacteria agent is a compound of bacteria from the genera *Nitrosomonas*, *Nitrococcus*, *Nitrospirillum*, *Nitrobacter*, *Nitrococcus*, and *Nitrocystis*. It is in powder form with a bacterial count of 150 × 10⁻⁶. 8 ~200×10 8 CFU / g, dosage 3.5g / L.

[0047] (4) Adjust the opening of the aeration pipe valve to control the dissolved oxygen content to 2-3 mg / L, and add 10% sodium bicarbonate solution by metering pump to control the pH value to 7.0-7.5.

[0048] (5) The ammonia nitrogen concentration in the filter bed was measured daily. On the 12th day of acclimatization, the ammonia nitrogen concentration dropped to 35 mg / L and a uniform biofilm with a thickness of 0.15-0.18 mm was formed on the surface of the ceramsite.

[0049] Water intake began on day 13. For the first four days, the intake load was 50% of the design load. From day 5 onwards, full load was applied. Monitoring showed that the effluent ammonia nitrogen concentration was 20–25 mg / L, and the actual average volumetric ammonia nitrogen loading of the filter was 75 g / m³. 3 ·d.

[0050] In comparison, the original aerobic tank was treated with 4 g / L of nitrifying bacteria for 36 days, resulting in an effluent ammonia nitrogen concentration of 45–55 mg / L and an average ammonia nitrogen volumetric loading rate of 45 g / m³. 3 ·d.

[0051] Example 3

[0052] A rubber factory's boiler flue gas is used to discharge wastewater at ultra-low emission rates. The wastewater volume is 30t / d, the salt content is 3-3.5%, and the ammonia nitrogen is 400-500mg / L. The ammonia nitrogen comes from the escape of ammonia during denitrification.

[0053] A method for treating high-salt ammonia-nitrogen-containing wastewater using micro-electrolysis coupled with nitrifying bacteria includes the following steps:

[0054] (1) The total volume of the aerated filter is 150m³. 3 It uses two aeration filters connected in series, and the size of a single aeration filter is... The effective depth of the filter bed is 11m.

[0055] (2) The amount of iron and carbon added to a single filter bed is 2.1t, m(Fe):m(C)=1:3, the voltage formed is 1.0~1.2V, the particle diameter is 1~2cm, and three layers of iron and carbon packing are set, with the height of each layer of iron and carbon packing being 10cm.

[0056] The dosage of ceramsite packing material in a single filter bed is 21m³. 3 Diameter 3-5mm, specific surface area 5-8m² 2 / g, the height of each layer of ceramsite filler is 1.2m, and the ceramsite is soaked in water to remove impurities.

[0057] (3) The raw water is pretreated by coagulation and sedimentation to remove hardness, heavy metals and suspended solids. The water is then introduced to a level of 10m, and the compressed air pipe valve is opened for pre-aeration for 24 hours.

[0058] The added nitrifying bacteria agent is a compound of bacteria from the genera *Nitrosomonas*, *Nitrococcus*, *Nitrospirillum*, *Nitrobacter*, *Nitrococcus*, and *Nitrocystis*. It is in powder form with a bacterial count of 150 × 10⁻⁶. 8 ~200×10 8 CFU / g, dosage 5g / L.

[0059] (4) Install an electric regulating valve on the compressed air pipeline to control the dissolved oxygen content to 2.5-3 mg / L, and add 10% sodium bicarbonate solution to the metering pump to control the pH value to 7.2-7.5.

[0060] (5) The ammonia nitrogen concentration in the filter bed was measured daily. On the 18th day of acclimatization, the ammonia nitrogen concentration dropped to 35 mg / L and a uniform biofilm with a thickness of 0.1 to 0.15 mm was formed on the surface of the ceramsite.

[0061] Water intake began on day 19. For the first three days, the intake load was 50% of the design load; from day 4 to 7, the intake load was 75% of the design load; and from day 8 onwards, full load was applied. Monitoring showed that the effluent ammonia nitrogen concentration was 20–25 mg / L, and the actual average volumetric ammonia nitrogen loading of the filter was 89 g / m³. 3 ·d.

[0062] Example 4

[0063] The apparatus and method are the same as in Example 1, except that: the amount of iron and carbon added to the single-cell filter is 3t, m(Fe):m(C) = 1:3, the voltage formed is 0.4-0.6V, the ammonia nitrogen concentration in the filter is measured daily, and on the 25th day of acclimatization, the ammonia nitrogen concentration drops to 40mg / L, and a uniform biofilm with a thickness of 0.08-0.1mm is formed on the surface of the ceramsite.

[0064] Water intake began on day 26. For the first three days, the intake load was 50% of the design load. From day 4 onwards, full load was applied. Monitoring showed that the effluent ammonia nitrogen concentration was 40–45 mg / L, and the actual average volumetric ammonia nitrogen loading of the filter was 38 g / m³. 3 ·d.

[0065] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for treating high-salt ammonia-nitrogen-containing wastewater using micro-electrolysis coupled with nitrifying bacteria, characterized in that... Includes the following steps: (1) Introduce high-salt wastewater containing ammonia nitrogen, pre-aerate for 24 hours, and then add nitrifying bacteria agent; (2) Aeration acclimatization for 10-20 days, during which dissolved oxygen and pH value are controlled; (3) Once acclimatization is complete, gradually increase the influent load; The apparatus used in the method includes an aeration tank reactor, which comprises an aeration structure, a filter plate structure, and a packing layer arranged sequentially from bottom to top. The packing layer consists of multiple layers of packing material arranged alternately from bottom to top in the order of iron-carbon packing material and ceramsite packing material. The aeration tank reactor is equipped with an online dissolved oxygen meter and an online pH meter. The wastewater has a salt content of 2.5-5% and an ammonia nitrogen concentration of 100-500 mg / L, calculated as sodium chloride. The dosage of the iron-carbon packing material is 20-30 g / L, the mass ratio of iron to carbon is 1:2-3, the voltage generated is 0.8-1.2 V, the particle diameter is 1-2 cm, and the height of a single layer of iron-carbon packing material is 5-10 cm. The ammonia nitrogen volumetric loading rate of the aeration tank reactor is 40–100 g / m³. 3 •d, the surface loading of the aeration tank reactor is 0.1–0.3 m. 3 / m 2 ·h; The diameter of the ceramsite filler is 3-5 mm, and the specific surface area is 5-8 m². 2 / g, the height of each layer of ceramsite packing is 0.5-1.3m, and the total volume is 15-40% of the volume of the aeration tank reactor; Nitrifying bacteria agent is a compound of bacteria from the genera *Nitrosomonas*, *Nitrosococcus*, *Nitrospirillum*, *Nitrobacter*, *Nitrococcus*, and *Nitrocystis*. It is in powder form and has a bacterial count of 100 × 10⁻⁶. 8 ~200×10 8 CFU / g, dosage 3-5g / L; During the acclimatization process, the aeration rate was adjusted to control the dissolved oxygen content at 2–3 mg / L, and sodium bicarbonate was added to control the pH value at 7.0–7.

5. When the biofilm formed on the surface of the ceramsite packing is 0.1–0.2 mm thick, and the ammonia nitrogen concentration in the reactor is 15–35 mg / L or decreases by 80–90%, it indicates that the acclimatization is complete.

2. The method for treating high-salt ammonia-nitrogen-containing wastewater by micro-electrolysis coupled with nitrifying bacteria according to claim 1, characterized in that: The aeration tank reactor is a circular or square aeration filter tank. The aeration tank reactor has an inlet at the bottom and an outlet at the top.

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