Three-dimensional natural ventilation-multi-pond coupled biofilm array tower wastewater treatment method

Abstract

This invention discloses a three-dimensional natural ventilation-multi-pond coupled biofilm array tower wastewater treatment method, belonging to the field of wastewater treatment technology. The system utilizes a unique periodic stacked composite functional layer design to construct alternating spaces between biofilm attachment zones and air circulation zones within the biological treatment tower. Employing high specific surface area biological packing materials, and with a cumulative total height of packing layers no less than 0.4 meters, the system achieves a biofilm attachment area gain of at least 600 times per unit area. The system leverages the thermal and wind pressure created by terrain elevation differences to drive natural airflow through the tower, achieving highly efficient, zero-energy oxygen mass transfer, with an oxygen supply intensity more than 500 times that of traditional oxidation ponds. As the core purification module of a low-energy wastewater zero-discharge system, this invention solves the fundamental contradictions of limited biomass and high oxygen supply energy consumption in traditional processes, achieving a hundredfold increase in treatment efficiency and a revolutionary reduction in energy consumption. It is suitable for decentralized and centralized treatment of various types of biodegradable wastewater.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a low-energy, high-load treatment system suitable for high-concentration organic wastewater and biodegradable wastewater such as domestic sewage, and in particular, a system and method that achieves an order-of-magnitude improvement in treatment efficiency per unit area by coupling a three-dimensional stacked structure with natural ventilation. Background Technology

[0002] Two prominent pain points exist in decentralized wastewater treatment and some industrial wastewater treatment: first, traditional natural treatment processes (such as oxidation ponds) are extremely inefficient and require huge land areas; second, high-efficiency treatment processes (such as activated sludge processes and biofilm reactors) are energy-intensive, with the core bottleneck being aeration energy consumption. The root cause lies in two physical limitations: 1) Biomass ceiling: traditional processes are mainly developed in a two-dimensional plane, and there is a theoretical upper limit to the biofilm attachment area that can be provided per unit area; 2) Oxygen supply ceiling: relying on natural reoxygenation of the water surface results in an extremely low rate; mechanical aeration, on the other hand, consumes enormous amounts of energy. Current technologies lack a disruptive solution that can simultaneously overcome the limitations of biomass and oxygen supply, achieving extremely high land utilization and extremely low operating energy consumption. Summary of the Invention

[0003] (a) Technical problems to be solved This invention aims to resolve the fundamental contradiction in traditional wastewater treatment processes where "high efficiency and low energy consumption are mutually exclusive," and provides a system and method that, through three-dimensional spatial reconstruction and the utilization of natural energy, can achieve a hundredfold increase in treatment capacity per unit of land while reducing the core oxygen supply energy consumption to near zero.

[0004] (II) Technical Solution A three-dimensional natural ventilation-multi-pond coupled biofilm array tower system, characterized in that it includes: At least one oxidation pond should be provided as a buffer and equalization unit for water volume. At least one three-dimensional biofilm treatment unit is in fluid communication with the oxidation pond; The three-dimensional biofilm treatment unit includes at least one biological treatment tower, and the biological treatment tower has multiple periodically stacked composite functional layers arranged inside it along its height direction. Each of the aforementioned composite functional layers is composed of a lower biofilm attachment area and an upper air circulation area arranged adjacent to each other. The biofilm attachment area is filled with granular or porous biological fillers with a high specific surface area (not less than 1500 m² / m³). The air circulation zone is a through cavity not occupied by solid filler, used for air circulation and distribution; The total cumulative height of the packing layer in all biofilm attachment zones within the biological treatment tower shall not be less than 0.4 meters.

[0005] Preferably, the three-dimensional biofilm treatment unit includes multiple biological treatment towers, each tower being arranged in an array (such as a co-located array or a surrounding array) coupled to the oxidation pond of the same level, forming a modular expansion of treatment capacity.

[0006] (III) Core theoretical breakthroughs and quantitative advantages of this invention The core of this invention lies in extending traditional planar processes to three-dimensional space through a three-dimensional stacking design, thereby achieving a geometric increase in biofilm attachment area and oxygen mass transfer capacity, and coupling it with natural ventilation to completely transform the oxygen supply method: 1. The principle of ultra-high specific surface area (breaking through the ceiling of biomass) Advantages of filler-grade materials: They use lightweight porous biological ceramic particles and other fillers, with a specific surface area of ​​up to 1500-2500 m² / m³.

[0007] System-level scale-up: The specific surface area of ​​the filler is scaled up at the system level through periodic stacking in the vertical direction.

[0008] Quantization gain: System-level effective specific surface area gain coefficient = specific surface area of ​​packing × total cumulative height of packing layer.

[0009] Example: With a filler specific surface area of ​​2000 m² / m³, and a design of 12 layers stacked (total height of filler layers 2.4 meters), the system-level specific surface area gain = 2000 × 2.4 = 4800 times (relative to unit floor area). By increasing the number of stacked layers to 96 (total height of filler layers 19.2 meters), the gain can reach 38400 times, which is a dimensional breakthrough compared to traditional processes (approximately 1 time).

[0010] 2. Highly efficient natural oxygen supply principle (breaking through the oxygen supply ceiling) Traditional limit: Traditional oxidation ponds rely on natural reoxygenation at the water surface, with a rate of only about 0.01-0.03 gO2 / (m²·h), resulting in a weak oxygen supply capacity.

[0011] The mechanism of this invention: Three-dimensional stacking creates a huge gas-liquid-film three-phase contact interface (i.e., a huge surface area of ​​the biofilm attachment zone), and a continuous airflow zone is designed. Utilizing the thermal pressure difference (chimney effect) formed by the high-level arrangement of the tower and the ambient wind pressure difference, air is driven to flow naturally and continuously through all airflow zones within the tower, and oxygen is supplied to the biofilm through gas-liquid-film mass transfer.

[0012] Quantitative comparison: With a comparable footprint, relying on three-dimensional ventilation and an ultra-large interface, the oxygen supply capacity of this invention is more than 500-1000 times that of traditional oxidation ponds. The measured oxygen supply intensity can reach 1.5-2.0 kgO2 / (m³ packing material·d), which is sufficient to support a high organic load of 0.8-1.2 kgCOD / (m³·d).

[0013] (iv) Beneficial effects 1. Revolutionary breakthrough in treatment efficiency: The biofilm area per unit area is increased by hundreds to tens of thousands of times, the oxygen supply capacity per unit area is increased by more than 500 times, it can stably withstand high organic loads, and the treatment capacity per unit area is 150-200 times higher than that of traditional oxidation ponds.

[0014] 2. Revolutionary reduction in energy consumption: The core oxygen supply process relies on natural ventilation, achieving zero power consumption. The system's energy consumption is mainly concentrated in wastewater lifting, with direct power consumption per ton of water treated being less than 0.8 kWh, saving 70-90% more energy than traditional aeration processes.

[0015] 3. Extreme conservation of land resources: Under the same processing scale, the land area can be reduced by more than 60%; or under the same land area, the processing capacity can be increased by a hundredfold.

[0016] 4. Perfect compatibility as a core purification unit: As the core purification reaction module of the entire "natural energy driven zero emission system", this array tower system perfectly matches the water quality and low energy consumption characteristics of the subsequent "distributed self-regulating filtration" inlet water requirements with its effluent quality and low energy consumption characteristics. It also provides a stable and clean water source guarantee for the terminal "enhanced natural evaporation" or "spray evaporation", which is the cornerstone for achieving low energy consumption and zero emissions throughout the entire process. Attached Figure Description

[0017] Figure 1 This is a top view of the planar layout of the system of the present invention (array surround type, pond surface superposition type).

[0018] Figure 2 Front view (array surround, pond surface overlay).

[0019] Figure 3 This is a left-side side view (array-surround, pond-surface overlay).

[0020] Figure 4 This is a combination diagram of array surround and pond surface superposition.

[0021] Figure 5 3D view of the array-surround shell Figure 6 Large-scale drawing of the core components of the biofilm array tower Figure 7 Topographical images of natural evaporation in mountain forest belts Figure 8 Photo 1 shows the use of natural evaporation in mountain forest belts. Detailed Implementation

[0022] Taking a daily treatment capacity of 100 tons of aquaculture wastewater as an example, the system is built on a mountain platform and includes six interconnected, seepage-proof oxidation ponds (single pond dimensions: 30m × 3m × 1.5m) and six corresponding biological treatment towers. The biological treatment towers are steel-framed structures, each measuring 30m × 3m × 1.5m, with three periodically stacked composite functional layers inside. Each layer has a 0.2-meter-high biofilm attachment zone filled with lightweight ceramsite with a specific surface area of ​​2000 m² / m³; the air circulation zone is 0.3 meters high. The total height of the packing layers in a single tower is 0.6 meters. The tower is suspended 0.5 meters above the oxidation ponds. Each tower has an integrated water distribution and filtration layer consisting of a water distribution branch pipe and an 80-mesh nylon filter screen at its top. Each oxidation pond is equipped with a circulating pump (1.5kW) to pump the pond water to the top of the corresponding tower for distribution. Wastewater flows through the packing layer under gravity, and after biodegradation, drips back into the original oxidation pond. The high-level tower arrangement and the chimney effect created by its internal structure drive natural airflow through each air circulation zone, providing oxygen to the biofilm. After multi-stage "pond-tower" circulation treatment, the effluent from the final oxidation pond (COD < 150 mg / L) can meet the requirements for subsequent advanced treatment or zero discharge. This embodiment of the system achieves highly efficient biochemical treatment within an area of ​​approximately 540 square meters, with no other power consumption besides the lifting and circulation pumps, demonstrating the significant advantages of this invention in improving efficiency, reducing energy consumption, and saving land.

Claims

1. A wastewater treatment method using a three-dimensional natural ventilation-multi-pond coupled biofilm array tower, characterized in that, This system is the core purification reaction module of a wastewater deep purification and zero-discharge system based on natural energy synergy and spatial coupling, including: At least a primary oxidation pond; At least one three-dimensional biofilm treatment unit is in fluid communication with the oxidation pond; The three-dimensional biofilm treatment unit includes at least one biological treatment tower, and at least two periodically stacked composite functional layers are arranged inside the biological treatment tower along its height direction. Each of the aforementioned composite functional layers is composed of a lower biofilm attachment area and an upper air circulation area arranged adjacent to each other. The biofilm attachment area is filled with granular or porous biological filler, and the specific surface area of ​​the biological filler is not less than 1500 m² / m³. The total cumulative height of the packing layer in all biofilm attachment zones within the biological treatment tower shall not be less than 0.4 meters; The air circulation zone is a through cavity not occupied by solid filler, used for the natural circulation and distribution of air; The biological treatment tower and the oxidation pond have a relative height difference in vertical space. This height difference is configured to drive or assist in driving natural air convection to flow through each of the air circulation zones, so as to achieve unpowered or low-power oxygen supply to the biofilm attachment zone.

2. The system according to claim 1, characterized in that, The specific surface area of ​​the biological packing material is not less than 2000 m² / m³, and the cumulative total height of the packing layer is preferably 0.4-4.8 meters, more preferably 2.4 meters (corresponding to 12 standard stacks), and the maximum height can reach 19.2 meters (corresponding to 96 stacks).

3. The system according to claim 1, characterized in that, The number of composite functional layers is 2-100 layers, the vertical height H1 of the biofilm attachment area is 0.1-0.5 meters, the vertical height H2 of the air circulation area is 0.1-0.9 meters, and the ratio of H1:H2 is between 1:1 and 1:

3.

4. The system according to claim 3, characterized in that, When the number of composite functional layers is 3, H1 = 0.2 meters, H2 = 0.3 meters, the total cumulative height of the filler layers is 0.6 meters, and the system-level specific surface area gain is not less than 1200 times; when the number of composite functional layers is 12, the total cumulative height of the filler layers is 2.4 meters, and the system-level specific surface area gain is not less than 4800 times.

5. The system according to claim 1, characterized in that, The three-dimensional biofilm treatment unit includes multiple biological treatment towers, each tower being coupled to the oxidation pond of the same level in a co-located array, linear array, or surrounding array, forming a scalable modular treatment cluster.

6. The system according to claim 1, characterized in that, There is a positive height difference ΔH between the centerline of the bottom surface of the biological treatment tower and the normal water level of the oxidation pond, where ΔH is 0.2-100 meters.

7. The system according to claim 1, characterized in that, The system also includes a ventilation drive module, which comprises: S1. Topographic elevation difference and structural module, which, by placing the biological treatment tower at a relatively high position, utilizes the thermal pressure difference and wind pressure difference inside and outside the tower as the main driving force to drive air to flow naturally through the air circulation zone; and / or S2. Mechanical auxiliary module, which includes a fan installed on the biological treatment tower for assisting or enhancing airflow through the air circulation zone when natural driving force is insufficient.

8. The system according to claim 7, characterized in that, The fan in the mechanical auxiliary module is a high-volume, low-speed negative pressure induced fan.

9. The system according to claim 1, characterized in that, The system is further integrated with a water distribution and filtration guarantee module, which includes: S1. A top-level water distribution and filtration unit, located at the very top of the biological treatment tower, is used to receive incoming water and perform uniform water distribution and primary filtration; and S2. Bottom gradient filtration unit, located in the easily maintained space at the bottom of the biological treatment tower, is used to perform gradient filtration from coarse to fine on the effluent after biological treatment.

10. The system according to claim 1, characterized in that, The effluent outlet of the oxidation pond is further connected to a zero-emission terminal module, which is selected from: S1. Enhanced natural evaporation unit, configured to distribute purified water to the transpiration surface of vegetation in open spaces; or S2. Spray evaporation unit, configured to atomize purified water and spray it into a high-level natural wind field.

11. A wastewater treatment method based on the system according to any one of claims 1-10, characterized in that, Includes the following steps: S1. The wastewater to be treated is introduced into the oxidation pond for buffering and equalization; S2. The wastewater in the oxidation pond is lifted or diverted to the top of the three-dimensional biofilm treatment unit coupled thereto; S3. Under the action of gravity, the sewage flows from top to bottom through the biofilm attachment area of ​​each of the composite functional layers, comes into contact with the microbial community attached to the biological packing and undergoes a biochemical reaction; S4. Simultaneously, air is driven by natural forces mainly composed of thermal pressure difference and / or wind pressure difference to flow through the air circulation area of ​​each of the composite functional layers, providing oxygen for the biochemical reaction through gas-liquid-film mass transfer; S5. The effluent treated by the three-dimensional biofilm treatment unit is returned to the oxidation pond for further recycling, or it is transported as deeply purified effluent to the subsequent filtration support module and zero-emission terminal module.

12. The method according to claim 11, characterized in that, In step S4, the oxygen supply intensity achieved by the system is not less than 0.8 kgO2 / (m³ packing material·d), which is sufficient to support an organic load of not less than 0.6 kgCOD / (m³ packing material·d); the preferred oxygen supply intensity is 1.5-2.0 kgO2 / (m³ packing material·d), and the supported organic load is 0.8-1.2 kgCOD / (m³ packing material·d).

13. The method according to claim 11, characterized in that, In step S4, the force driving the airflow mainly comes from the thermal pressure difference generated by the temperature difference inside and outside the biological treatment tower and / or the wind pressure difference generated by the ambient wind, so that the core oxygen supply process achieves zero power consumption.

14. The method according to claim 11, characterized in that, In step S4, when the natural driving force is insufficient, the mechanical auxiliary ventilation device is activated to provide part or all of the airflow driving force.

15. A wastewater deep purification and zero-discharge system, characterized in that, The system includes a multi-pond coupled three-dimensional natural ventilation biofilm array tower system as described in any one of claims 1-10 arranged in series or in an integrated manner as a core purification reaction module, a water distribution and filtration guarantee module as described in claim 3, and a zero-emission terminal module as described in claim 10.

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