Microalgae-Wetland Coupled System for Enhanced Denitrification
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Solution Overview
Problem
The constructed wetland in prior art systems has a limited denitrifying capacity, which restricts the effective removal of nitrogen pollutants from sewage.
Innovation Solution
A microalgae culturing pond-constructed wetland coupled system is introduced, where microalgae are cultured in a pond using sewage as a medium, and the algae-containing water is added to the constructed wetland. A portion of the recovered microalgae is directed into an anoxic denitrification area within the wetland, where they lyse and provide a carbon source for enhanced denitrification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If microalgae are added to the surface of constructed wetland, then oxygen supply is improved, but carbon source for denitrification is insufficient
Solution Approach 1:
The system divides microalgae utilization into two segments: (1) microalgae at the surface provide oxygen through photosynthesis, and (2) lysed microalgae cells in the anoxic zone provide carbon source for denitrification. This segmentation allows simultaneous optimization of both oxygen supply and carbon source availability.
Solution Approach 2:
The patent introduces an intermediary mechanism where microalgae serve dual functions: living microalgae at the surface act as oxygen producers, while lysed microalgae cells in the anoxic zone act as carbon source. The flow guide pipe serves as an intermediary device to deliver lysed microalgae to the appropriate zone.
2Productivity
If aeration and tidal flow are applied to remove ammonia nitrogen, then removal rate is improved, but operating cost increases
Solution Approach 1:
The system employs self-service mechanisms where microalgae naturally perform oxygen production through photosynthesis and provide organic carbon through lysis, eliminating the need for external aeration equipment and reducing operating costs while maintaining high ammonia nitrogen removal rates.
Solution Approach 2:
The patent changes the chemical parameters of the wetland system by introducing microalgae that naturally alter oxygen and carbon concentrations, replacing mechanical aeration with biological processes that achieve the same purification effect at lower cost.
3Productivity
If microalgae are added to constructed wetland, then water quality purification is improved, but microalgae dosage requirement is high
Solution Approach 1:
The patent makes microalgae multi-functional by having them simultaneously serve as oxygen producers in aerobic zones and carbon sources in anoxic zones. This universality maximizes the utilization efficiency of each microalgae cell, reducing the total dosage required while enhancing overall water quality purification capacity.
Solution Approach 2:
The patent converts the natural lysis (death) of microalgae cells, which would normally be considered waste or harm, into a beneficial carbon source for denitrification. This transformation allows the system to utilize microalgae more efficiently, reducing the dosage needed while improving nitrogen removal.
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 maximal nitrogen removal with minimal microalgae dosage by optimizing the introduction of microalgae into the anoxic denitrification area, thereby improving the denitrifying capacity of the constructed wetland.
Implementation Method 1
converts pollutants such as nitrogen and phosphorus in sewage into microalgae biomasses by means of photosynthesis of microalgae
Implementation Method 2
The algae-containing water enters the surface of the constructed wetland, and generates oxygen by means of photosynthesis, which can strengthen oxygen supply of the constructed wetland
Implementation Method 3
a part of recovered microalgae is introduced into the anoxic denitrification functional area away from the surface in the constructed wetland by means of a flow guide pipe, algae cells entering a deep layer of the wetland are lysed and dead due to adverse conditions, and the lytic algae cells as a carbon source promote denitrification in the wetland
Implementation Method 4
Owing to oxygen exudation of plant root systems and low atmospheric oxygen-enriched efficiency in the wetland
Data Source
AI summary
A system that relates to the technical field of sewage purification includes microalgae culturing pond and constructed wetland that are connected in series. A microalgae capturing filler is arranged in the microalgae culturing pond, algae-containing water obtained from microalgae capturing filler is communicated with the constructed wetland for oxygen transfer and forming algal-bacterial mutualistic symbiosis for strengthened pollutant removal, and part of captured microalgae is introduced into an anoxic denitrification functional area away from a surface in constructed wetland by flow guide pipe. Microalgae culture and sewage purification are realized in microalgae culturing pond by taking sewage as a culture medium, 80% or more of the microalgae biomasses in microalgae culturing pond are recovered with low cost, part of microalgae is introduced into the anoxic denitrification functional area away from the surface in the constructed wetland, and lytic algae cells serving as a carbon source promote denitrification in the wetland.