Constructed Wetland Carbon Source Layers for Stable Nitrogen Removal
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Solution Overview
Problem
Existing methods for supplying carbon in constructed wetlands result in high costs and inefficient operation due to the use of unsustainable and high-cost carbon sources, leading to reduced nitrogen removal efficiency and increased operational instability.
Innovation Solution
A constructed wetland structure utilizing modified plant straws, straw biochar, and woody biochar as carbon sources, arranged in specified layers with controlled distribution and periodic replacement, ensuring stable and uniform carbon release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbon source materials (glucose, polyhydroxyalkanoate, liquid biological carbon source) are used, then nitrogen removal effect is improved, but operating costs increase significantly
Solution Approach 1:
The patent replaces expensive conventional carbon sources with cheap biomass materials (corn straws, reed straws, cattail straws, canna straws, wetland plant straws) that can be locally sourced and disposed of after use. These disposable carbon sources are treated with alkali to enhance carbon release, achieving effective nitrogen removal while dramatically reducing operating costs compared to expensive conventional carbon sources like glucose and polyhydroxyalkanoate.
Solution Approach 2:
The patent utilizes wetland plants themselves as carbon sources by collecting and treating their straws. This self-service approach allows the wetland system to provide its own carbon supplementation needs using readily available biomass from within the system, eliminating dependence on external expensive carbon source purchases and reducing operating costs.
2Reliability
If carbon sources are supplemented at high frequency to maintain nitrogen removal at high load, then nitrogen removal effect is improved, but operating stability deteriorates
Solution Approach 1:
The patent performs preliminary treatment of biomass carbon sources by alkali treatment before placement in the wetland. This pre-treatment enhances the carbon release characteristics and durability of the carbon sources, allowing them to maintain effective nitrogen removal over extended periods without frequent supplementation, thereby improving operating stability.
Solution Approach 2:
The patent modifies the physical and chemical parameters of biomass carbon sources through alkali treatment, which alters their decomposition rate and carbon release characteristics. This parameter change enables the carbon sources to release carbon more steadily and sustainably, reducing the need for frequent supplementation and improving system stability.
3Ease of operation
If unordered carbon source release is used, then carbon source supplementation is simplified, but water quality purification depth deteriorates
Solution Approach 1:
The patent creates zones with different carbon source release characteristics by using alkali-treated biomass materials with controlled decomposition rates. Different areas of the wetland receive carbon sources tailored to local conditions, ensuring uniform and controlled carbon distribution throughout the system. This localized quality control maintains deep water purification while simplifying supplementation operations.
Solution Approach 2:
The patent ensures continuous and uniform carbon source release through alkali-treated biomass materials that decompose steadily over time. This continuous action prevents carbon source deficiency that would otherwise require frequent supplementation, maintaining consistent nitrogen removal efficiency and deep water quality purification throughout the operational period.
4Manufacturing precision
If complex carbon source addition methods are used, then carbon source distribution uniformity is improved, but device complexity increases
Solution Approach 1:
The patent employs alkali-treated biomass carbon sources that automatically distribute themselves uniformly throughout the wetland substrate through natural decomposition and water flow. This self-distribution mechanism eliminates the need for complex injection systems, pumps, or controlled release devices, achieving uniform carbon source distribution while keeping the system simple and easy to operate.
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
The method achieves stable carbon source distribution, improving nitrogen removal rates by 10% or more and reducing operating costs by 20% or more, with a carbon source use cycle extended by 30% or more compared to conventional methods.
Implementation Method 1
A constructed wetland structure utilizing modified plant straws, straw biochar, and woody biochar as carbon sources, arranged in specified layers with controlled distribution and periodic replacement, ensuring stable and uniform carbon release
Data Source
AI summary
Disclosed are a constructed wetland structure and methods for preparing and using a carbon source, which relate to the technical field of biological treatment of water pollutants, and solve the problems of poor uniformity, complexity, unsatisfactory effects and high operating costs in existing carbon source adding methods. The present disclosure includes a water inlet pond, a treatment unit, and a water storage pond, which communicate in sequence. In the treatment unit, plant straws and biochar are used to prepare a carbon source. By modifying the carbon source material, the carbon source is released stably. By arranging carbon source layers, under the action of a water flow, the uniformity of carbon source distribution is guaranteed. The carbon source is periodically cleaned and replaced. Carbon source material is a biomass material which features a wide source and low costs.