A zeolite fluidized bed batch nitrosation reactor
By using a zeolite fluidized bed and an arch-bridge mesh separator in the nitrification reactor, the difficulties of nitrification and sludge loss in the treatment of low-concentration ammonia nitrogen wastewater by traditional reactors were solved, achieving efficient nitrification and low-energy wastewater treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2025-05-08
- Publication Date
- 2026-06-26
AI Technical Summary
Traditional completely mixed nitrification reactors face challenges in treating low-concentration ammonia nitrogen wastewater, including difficulty in enriching nitrifying bacteria, severe sludge loss, poor nitrification efficiency, and long reaction times. Existing improvement measures, such as biofilm reactors and sequencing batch reactors, also present challenges such as packing blockage and complex operation.
A zeolite fluidized bed intermittent nitrification reactor is adopted, using natural zeolite as a carrier. Free ammonia is enriched through ion exchange adsorption, and sludge separation is achieved by combining an arch-bridge type mesh separator. Intermittent aeration and stirring devices are used to promote mass transfer, form a biofilm, and improve nitrification efficiency.
It achieves efficient nitrification of low-concentration ammonia nitrogen wastewater, resulting in excellent effluent quality, reduced energy consumption, and applicability to the treatment of municipal sewage and industrial wastewater, thus lowering operating costs.
Smart Images
Figure CN224411534U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of wastewater biological treatment technology, specifically relating to a zeolite fluidized bed intermittent nitrification reactor. Background Technology
[0002] Anammox is a highly efficient, low-energy biological treatment technology widely used in the treatment of industrial ammonia nitrogen wastewater. This process uses nitrite (NO2-) as the key electron acceptor, reacting with ammonia nitrogen (NH4+). + Nitrification directly generates nitrogen (N2) under anaerobic conditions, thus achieving efficient nitrogen removal and playing a crucial role in anaerobic ammonia oxidation systems. Especially for low-concentration ammonia nitrogen wastewater, short-cut nitrification is often used as pretreatment. However, traditional completely mixed nitrification reactors (CSTRs) have the following significant problems when treating low-concentration ammonia nitrogen wastewater (such as municipal sewage, aquaculture wastewater, and some industrial wastewater):
[0003] 1. Difficulty in accumulating nitrite-oxidizing bacteria: At low substrate concentrations, nitrite-oxidizing bacteria (NOB, such as Nitrobacter) easily compete with ammonia-oxidizing bacteria (AOB, such as Nitrosomonas), leading to further oxidation of NO2- to nitrate (NO3-), thus destroying the NO2- / NH4+ ratio required for Anammox. + Proportion.
[0004] 2. Severe sludge loss: The completely mixed flow state results in poor sludge settling performance, making it difficult to retain biomass and affecting the long-term stable enrichment of nitrifying bacteria.
[0005] 3. Poor nitrite formation: At low ammonia nitrogen concentrations, AOB metabolic activity is limited, and the nitrite accumulation rate (NAR) is usually below 60%, which is insufficient to meet the subsequent Anammox requirements.
[0006] 4. Long reaction time: To compensate for the effects of low substrate concentration, traditional reactors need to be extended, resulting in a large reactor volume and increased operating costs.
[0007] To address the aforementioned issues, existing technologies attempt to improve sludge retention and nitrification efficiency using biofilm reactors (such as MBBRs) or sequencing batch reactors (SBRs), but challenges remain, including packing clogging, mass transfer limitations, and operational complexity. Therefore, there is an urgent need to develop a novel reactor capable of efficiently enriching AOB, suppressing NOB, and stably maintaining a high nitrite accumulation rate under low ammonia nitrogen conditions, while simultaneously optimizing sludge retention capacity to meet the requirements of subsequent anaerobic ammonia oxidation processes. Utility Model Content
[0008] To address the shortcomings and deficiencies of existing technologies, the main objective of this invention is to provide a zeolite fluidized bed intermittent nitrification reactor.
[0009] The objective of this utility model is achieved through the following technical solution:
[0010] A zeolite fluidized bed intermittent nitrification reactor includes an inlet system (1), an aeration system (2), a stirring device (3), a mesh screen separator (4), an overflow weir (5), an outlet system (6), and a reactor body (7).
[0011] The water inlet system (1) includes an inlet pipe (101) and an inlet pump (102), the inlet pipe (101) and the inlet pump (102) are connected, and the inlet pipe (101) is connected to the bottom of the reactor body (7); the aeration system (2) includes an aeration perforated pipe (201) and an aeration device (202), the aeration perforated pipe (201) is connected to the bottom of the reactor body (7); the stirring device (3) extends vertically along the longitudinal center line of the reactor body (7), and the blades are located in the middle working area of the reactor; the mesh isolator (4) is installed across the upper opening of the reactor body (7), and the central axis of the mesh isolator coincides with the longitudinal center line of the reactor body; the overflow weir (5) is set at the upper part of the reactor body (7); the water outlet system (6) is connected to the overflow weir (5), and the reactor body (7) is filled with zeolite packing (8).
[0012] Preferably, the mesh isolator (4) is a composite structure, including an arched body and a protruding structure disposed on the upper part of the arched body. The protruding structure is disposed centrally along the axial direction of the arched body, and the arched body and the protruding structure disposed on its upper part form a continuous and integrated cavity.
[0013] Preferably, the arc-shaped edges of the arched body are tangent to the inner walls of the two right-angled long sides of the reactor body (7).
[0014] Preferably, the mesh isolator (4) is detachably connected to the reactor body.
[0015] Preferably, the detachable connection is a snap-fit connection.
[0016] Preferably, the mesh isolator (4) is located at 1 / 5 to 1 / 3 of the upper end of the reactor body.
[0017] Preferably, the overflow weir (5) is a double-sided overflow weir, including an overflow plate and an overflow trough. The top of the overflow plate is provided with a continuous toothed structure, and the overflow trough is a square ring. The water that has completed the reaction in the reactor overflows through the overflow plate into the square overflow trough, and after being buffered in the overflow trough, it enters the water outlet system and flows out.
[0018] Preferably, the overflow weir is fixedly attached to the upper part of the reactor body (7) by bonding.
[0019] Preferably, the inlet pipe (101) and the aeration perforated pipe (201) are symmetrically distributed along the central axis at the bottom of the reactor body (7). After the wastewater enters the reactor, it comes into short-distance contact with the airflow, thereby achieving rapid and uniform mixing of wastewater and zeolite sludge.
[0020] Preferably, the water outlet system (6) drains water through the outlet pipe under the action of gravity, and the water outlet flow rate is regulated by controlling the inlet pump (102) to adjust the inlet flow rate.
[0021] Preferably, the zeolite filler (8) has a particle size of 3-10 mm and a density of 6-7 g / cm³. 3 Zeolite filler has a filling rate of 30-60%, and is abundant, inexpensive and readily available.
[0022] Preferably, the zeolite filler (8) is 3-10 mm green zeolite powder with a density of 6.35 g / cm³. 3 This improves the adsorption and enrichment efficiency of free ammonia, serving as a carrier for microbial growth. The mobile zeolite carrier not only provides microorganisms with enriched ammonia nitrogen as nutrients, enhancing their activity and promoting nitrification, but the high-frequency collisions of the zeolite also promote ion exchange on its surface.
[0023] This design utilizes zeolite as the fluidized bed carrier, leveraging its powerful ion exchange capacity to adsorb and enrich free ammonia in wastewater, thereby improving nitrification efficiency. As a carrier, nitrifying bacteria grow on the surface of zeolite particles, forming a biofilm to purify the wastewater. In the zeolite fluidized bed, the zeolite is in a fluidized state, and the wastewater flows upwards at a certain velocity, coming into full and repeated contact with the zeolite under the combined effects of aeration and stirring. During the mixing process of sludge and zeolite, nitrifying bacteria aggregate on the zeolite surface to form a microbial biofilm, achieving microbial attachment and growth. Due to the small size and large specific surface area of the zeolite particles, they rub and collide with each other under aerated and fluidized conditions, resulting in high biofilm activity, thus enhancing the mass transfer process and achieving efficient nitrogen removal from the wastewater. An arch-shaped isolator installed in the upper zone of the reactor isolates the zeolite in the middle zone, significantly reducing the loss of the zeolite carrier and facilitating the enrichment and growth of microorganisms.
[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0025] 1. Utilizing natural zeolite to adsorb and enrich free ammonia, which is gradually released through ion exchange during fluidization, the high efficiency of enriching low-concentration free ammonia is achieved. The zeolite surface enriched with ammonia nitrogen is more attractive to the attachment and growth of nitrifying bacteria, greatly improving the nitrification rate.
[0026] 2. The arch-bridge type mesh isolator isolates the zeolite biofilm in the reaction zone, achieving the separation of flocculent sludge and improving the quality of effluent (SS<15mg / L).
[0027] 3. Compared with traditional processes, aeration energy consumption is reduced by 40%, and stirring energy consumption is reduced by 25%.
[0028] 4. A sequencing batch reactor that achieves efficient nitrification of low-concentration ammonia nitrogen through the synergistic effect of zeolite adsorption enrichment and dynamic sludge separation is suitable for the treatment of low-concentration ammonia nitrogen wastewater such as municipal sewage. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the structure of the intermittent nitrification reactor based on a zeolite fluidized bed according to an embodiment of the present invention;
[0030] 1-Water inlet system, 101-Water inlet pipe, 102-Water inlet pump; 2-Aeration system, 201-Aeration perforated pipe, 202-Aeration device (including air compressor and air flow meter); 3-Stirring device; 4-Mesh isolator; 5-Overflow weir; 6-Water outlet system; 7-Reactor body; 8-Zeolite packing. Detailed Implementation
[0031] The present invention will be further described in detail below with reference to specific embodiments. However, the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.
[0032] Example 1
[0033] Urban wastewater treatment plant low-concentration ammonia nitrogen enhanced treatment project
[0034] Reactor size: The reactor body is a rectangular steel structure with an effective volume of 4.5 m³. 3 (1.5m long and wide, 2m high), filled with natural zeolite packing material with a particle size of 3-10mm (40% filling rate). The mesh separator uses arch-shaped stainless steel mesh (0.5mm aperture), installed in the upper section of the reactor, dividing the reaction zone into the upper effluent zone and the lower zeolite biofilm reaction zone.
[0035] Working principle:
[0036] 1. Inlet stage: Wastewater is injected through the bottom inlet system at a flow rate of 10m³. 3 / h, ammonia nitrogen concentration 20-30mg / L. Zeolite packing rapidly adsorbs free ammonia and enriches it on the biofilm surface. 2. Aeration and stirring: Intermittent aeration mode is adopted (aeration for 30min / stop for 15min), DO is controlled at 0.5-1.0mg / L. A stirring device (30rpm) promotes mixing and mass transfer and prevents zeolite packing from caking. 3. Reaction and separation: Nitrifying bacteria form a biofilm on the zeolite surface, oxidizing ammonia nitrogen to nitrite. A mesh separator intercepts flocculent sludge to prevent it from being lost with the effluent. 4. Effluent stage: The treated water enters the effluent system through an overflow weir (2.8m high), with SS concentration below 10mg / L.
[0037] Operational results: Ammonia nitrogen removal rate: over 95%, effluent ammonia nitrogen <1.5mg / L; Nitrite accumulation rate: 90%-95%, no nitrate accumulation detected;
[0038] Stability: Under conditions of 25-30℃ and pH 7.5-8.0, the system has strong resistance to shock loads, and the zeolite packing needs to be regenerated every 6 months.
[0039] The above cases have all been verified through actual engineering projects. By combining process parameter optimization and equipment innovation, the stability and economy of the nitrification process have been significantly improved. For further technical details, please refer to relevant literature and engineering reports.
[0040] Example 2
[0041] Industrial wastewater high ammonia nitrogen short-cut denitrification retrofit project
[0042] Reactor size: The reactor body is a rectangular concrete structure with an effective volume of 20m³. 3 (5m long × 2m wide × 2m high), zeolite packing is layered (total filling rate 50%), and the mesh isolator is a double-layer nylon mesh (1mm aperture) located in the middle of the reactor.
[0043] Working principle:
[0044] 1. Influent and Pretreatment: High ammonia nitrogen wastewater (80-100 mg / L) enters evenly through a bottom distributor. Zeolite adsorbs free ammonia and buffers concentration fluctuations. 2. Aeration Control: Low-oxygen intermittent aeration (DO = 0.7-1.2 mg / L) is used, with an aeration cycle of 35 min / 10 min. The aeration system is equipped with microporous aeration discs, increasing oxygen utilization by 30%. 3. Biofilm and Sludge Synergy: A stirring device (20 rpm) maintains the fluidized state of the packing material. A mesh screen retainer traps detached biofilm in the reaction zone, while flocculent sludge settles and is periodically discharged. 4. Effluent Optimization: The water level is regulated by an overflow weir, ensuring effluent ammonia nitrogen <5 mg / L and nitrite content above 90%, allowing it to directly enter the subsequent anaerobic ammonia oxidation process.
[0045] Operational results: Treatment efficiency: Ammonia nitrogen load reaches 0.3 kg / (m³) 3 •d) The nitrite accumulation rate remained stable at 91%-93%;
[0046] Energy consumption comparison: Compared with traditional processes, aeration energy consumption is reduced by 40% and stirring energy consumption is reduced by 25%;
[0047] Economic efficiency: Zeolite filler costs 60% less than activated carbon, and the regeneration cycle is extended to 1 year.
[0048] Summary of technical advantages
[0049] 1. High-efficiency adsorption of zeolite packing: Natural zeolite adsorbs free ammonia through ion exchange, solving the problem of low-concentration ammonia nitrogen enrichment and enhancing the activity of nitrifying bacteria.
[0050] 2. Structural innovation: The arch-bridge type mesh separator achieves physical separation of biofilm and flocculent sludge, ensuring effluent quality (SS<15mg / L).
[0051] 3. Operational flexibility: Intermittent aeration and stirring are controlled in tandem to adapt to water quality fluctuations, while reducing N2O release (20% less than continuous aeration).
[0052] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.
Claims
1. A zeolite fluidized bed intermittent nitrification reactor, characterized in that, It includes an inlet system (1), an aeration system (2), a stirring device (3), a mesh isolator (4), an overflow weir (5), an outlet system (6), and a reactor body (7); The water inlet system (1) includes an inlet pipe (101) and an inlet pump (102), the inlet pipe (101) and the inlet pump (102) are connected, and the inlet pipe (101) is connected to the bottom of the reactor body (7); the aeration system (2) includes an aeration perforated pipe (201) and an aeration device (202), the aeration perforated pipe (201) is connected to the bottom of the reactor body (7); the stirring device (3) extends vertically along the longitudinal center line of the reactor body (7), and the blades are located in the middle working area of the reactor; the mesh isolator (4) is installed across the upper opening of the reactor body (7), and the central axis of the mesh isolator coincides with the longitudinal center line of the reactor body; the overflow weir (5) is set at the upper part of the reactor body (7); the water outlet system (6) is connected to the overflow weir (5), and the reactor body (7) is filled with zeolite packing (8).
2. The zeolite fluidized bed intermittent nitrification reactor according to claim 1, characterized in that, The mesh isolator (4) is a composite structure, including an arched body and a protruding structure set on the upper part of the arched body. The protruding structure is set in the center along the axial direction of the arched body, and the arched body and the protruding structure set on its upper part form a continuous and integrated cavity.
3. The zeolite fluidized bed intermittent nitrification reactor according to claim 2, characterized in that, The arc-shaped edges of the arched main body are tangent to the inner walls of the two right-angled long sides of the reactor body (7).
4. The zeolite fluidized bed intermittent nitrification reactor according to claim 1, characterized in that, The mesh isolator (4) is detachably connected to the reactor body.
5. The zeolite fluidized bed intermittent nitrification reactor according to claim 4, characterized in that, The detachable connection is a snap-fit connection.
6. The zeolite fluidized bed intermittent nitrification reactor according to claim 1, characterized in that, The mesh isolator (4) is located at 1 / 5 to 1 / 3 of the upper part of the reactor body.
7. The zeolite fluidized bed intermittent nitrification reactor according to claim 1, characterized in that, The overflow weir (5) is a double-sided overflow weir, including an overflow plate and an overflow trough, and the top of the overflow plate is provided with a continuous toothed structure.
8. The zeolite fluidized bed intermittent nitrification reactor according to claim 1, characterized in that, The overflow weir is fixedly attached to the upper part of the reactor body (7) by bonding.
9. The zeolite fluidized bed intermittent nitrification reactor according to claim 1, characterized in that... The inlet pipe (101) and the aeration perforated pipe (201) are symmetrically distributed along the central axis at the bottom of the reactor body (7).
10. The zeolite fluidized bed intermittent nitrification reactor according to claim 1, characterized in that, The particle size of the zeolite filler (8) is 3-10 mm, the density is 6-7 g / cm 3 , and the filling rate of the zeolite filler is 30-60%.