Nested A2O Wastewater System for Deep Denitrification
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Solution Overview
Problem
Existing sewage biological treatment processes are inefficient and energy-intensive, particularly in anaerobic and oxic processes, and struggle to meet stringent discharge standards for industrial wastewater with high COD and nitrogen concentrations, leading to high energy consumption and large land occupancy.
Innovation Solution
A deep denitrification treatment system using a high-oxygen three-phase contact process, incorporating an annular anaerobic treatment device, uniform water distribution, high-oxygen three-phase contact biological oxidative degradation, nitrification liquid collecting and shunting, annular nitrification liquid anoxic nitrification, and sludge sedimentation reflux clean water discharge devices, which enables one-time anoxic nitrification, internal reflux, sedimentation, and sludge reflux treatment to meet national first-class discharge standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional independent plane stepped structures are used for anaerobic, facultative, and oxic processes, then each process can be independently operated, but the system occupies large area and has high cost
Solution Approach 1:
The patent implements a nested vertical structure where the oxic process device is positioned above the anoxic process device, which in turn is positioned above the anaerobic process device. This nested arrangement allows multiple independent treatment processes to occupy a minimized footprint area by stacking them vertically, resolving the contradiction between independent operation capability and land occupancy.
Solution Approach 2:
The patent transitions from conventional horizontal plane-stepped arrangement to a vertical three-dimensional stacked configuration. By utilizing the vertical dimension, the system maintains independent operation of each process while dramatically reducing the horizontal land area required, thus resolving the contradiction between operational independence and space efficiency.
2Stability of the object's composition
If submersible mixer or air micro-aeration airflow is used for stirring in anaerobic and facultative processes, then microbial strains are prevented from settling, but energy consumption is high and there are blind angles
Solution Approach 1:
The patent removes the conventional submersible mixers and air micro-aeration systems from the anaerobic and facultative processes. Instead, it introduces an internal reflux mechanism that uses hydraulic flow to maintain microbial suspension, eliminating the need for high-energy mechanical or aerative mixing while preventing settler blind angles.
Solution Approach 2:
The system employs an internal reflux mechanism where treated water flows downward to create hydraulic circulation that naturally keeps microbial strains suspended. This self-service approach uses the process flow itself to achieve mixing and suspension without requiring additional energy-consuming mechanical devices.
3Use of energy by moving object
If air micro-aeration airflow is used for stirring, then oxygen is dissolved in water, but the basic requirement of dissolved oxygen is not sufficient for deep denitrification
Solution Approach 1:
The patent replaces conventional air micro-aeration with a high-oxygen three-phase contact device that uses pure oxygen or high-concentration oxygen gas. This strong oxidant approach dramatically increases oxygen dissolution efficiency and achieves the high dissolved oxygen levels required for deep denitrification, resolving the contradiction between energy-efficient oxygen dissolution and sufficient dissolved oxygen levels.
4Productivity
If conventional A/O tower with three-phase contact is used, then most COD and nitrogen organics are removed, but high COD and total nitrogen remain and it is not suitable for industrial wastewater with high concentration
Solution Approach 1:
The patent implements a continuous internal reflux mechanism where nitrified water from the oxic process continuously flows to the anoxic process, and treated water from lower layers continuously circulates upward. This continuous hydraulic action ensures sustained high-level treatment, enabling the system to reliably handle high-concentration industrial wastewater by maintaining continuous pollutant removal rather than batch-wise treatment.
Solution Approach 2:
The patent merges multiple treatment functions into an integrated vertical system where anaerobic, anoxic, and oxic processes are stacked and hydraulically connected. This integration allows simultaneous COD removal, nitrification, and denitrification to occur in sequence, achieving deep removal of both COD and total nitrogen from high-concentration industrial wastewater.
5Reliability
If multiple lifting and reflux operations are performed to meet strict discharge standards, then treatment effectiveness is improved, but energy consumption and system complexity increase
Solution Approach 1:
The patent designs the vertical stacked structure with gravity-assisted hydraulic flow between layers. The elevation differences between anaerobic, anoxic, and oxic layers create natural hydraulic gradients that drive internal reflux without requiring multiple mechanical lifters. This equipotential design uses gravity to achieve the necessary water circulation for meeting discharge standards while minimizing energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system achieves efficient deep denitrification, reducing energy consumption and land use while ensuring compliance with stringent discharge standards by optimizing microbial activity and pollutant mixing, resulting in effective nitrogen removal from wastewater.
Implementation Method 1
The high-oxygen three-phase contact biological oxidative degradation device is used for converting ammonia nitrogen in wastewater into nitrate nitrogen after nitrification reaction in an oxic process
Implementation Method 2
The annular nitrification liquid anoxic nitrification device is used for carrying out anoxic denitrification reaction on the nitrate nitrogen under a condition of having a carbon source to generate nitrogen dioxide and nitrogen
Implementation Method 3
sludge sedimentation reflux clean water discharge device
Data Source
AI summary
A deep denitrification treatment system for wastewater by A2O based on high-oxygen three-phase contact is provided, including an annular anaerobic treatment device, a uniform water distribution device, a high-oxygen three-phase contact biological oxidative degradation device, a nitrification liquid collecting and shunting device, an annular nitrification liquid anoxic nitrification device and a sludge sedimentation reflux clean water discharge device sequentially connected between a water inlet and a water outlet, where the annular anaerobic treatment device surrounds a periphery of the annular nitrification liquid anoxic nitrification device, the annular nitrification liquid anoxic nitrification device surrounds a periphery of the sludge sedimentation reflux clean water discharge device, and an upper part of the sludge sedimentation reflux clean water discharge device is sequentially provided with the nitrification liquid collecting and shunting device, the high-oxygen three-phase contact biological oxidative degradation device and the uniform water distribution device.