Vertical-Flow Reed Bed Filter for Effluent Nitrogen Removal
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Solution Overview
Problem
Current effluent treatment methods for small and medium-sized communities face challenges in efficiently eliminating nitrogenous pollutants, requiring high maintenance, energy, and land use, while also needing additional carbon sources for denitrifying bacteria, which increases costs and complexity.
Innovation Solution
A biological treatment process using a filter planted with reeds with vertical flow, where nitrification and denitrification occur simultaneously, utilizing sewage sludge as a carbon source, eliminating the need for external carbon additions and optimizing denitrification efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional nitrification-denitrification methods are used, then nitrogenous pollutants are eliminated, but additional carbon sources (methanol) must be added, increasing operational costs and complexity
Solution Approach 1:
The system uses the effluent's own carbonaceous matter as the carbon source for denitrifying bacteria, eliminating the need for external carbon source addition. The organic matter naturally present in the wastewater serves the dual purpose of food for heterotrophic bacteria and reducing agent for nitrate reduction.
Solution Approach 2:
The same effluent serves multiple functions: it provides the carbon source for denitrification, acts as the substrate for heterotrophic bacteria, and is the medium being treated. This multi-functionality eliminates the need for separate carbon source addition systems.
2Productivity
If intensive biological processes like activated sludge are used, then treatment efficiency is improved, but energy consumption and maintenance requirements increase
Solution Approach 1:
The system uses periodic tidal flow to alternately flood and drain the bed, creating alternating aerobic and anoxic conditions without requiring continuous aeration energy input. The natural flooding cycle provides oxygen during inundation and creates denitrification conditions during drainage.
Solution Approach 2:
The system replaces mechanical aeration systems with natural tidal flooding to provide oxygenation. The kinetic energy of incoming tide water provides mixing and oxygen transfer, eliminating the need for electrically-powered aerators and mixers.
3Use of energy by moving object
If extensive biological processes like lagooning are used, then energy consumption is reduced, but large land surfaces are required
Solution Approach 1:
The system creates localized aerobic and anoxic zones within a compact vertical structure through tidal flooding. The flooded zones provide aerobic conditions while intertidal zones provide anoxic conditions, enabling both nitrification and denitrification in a small footprint.
Solution Approach 2:
The system transitions from horizontal land use (lagooning) to vertical land use with tidal flooding. The tidal cycle creates temporal separation of aerobic and anoxic conditions, allowing high treatment efficiency in a compact vertical footprint rather than requiring large horizontal areas.
4Reliability
If separate facilities are used for nitrification and denitrification, then each process can be optimized, but device complexity and land use increase
Solution Approach 1:
The system combines nitrification and denitrification into a single tidal flow bed. The tidal flooding creates alternating aerobic (nitrification) and anoxic (denitrification) conditions in the same physical space, eliminating the need for separate facilities while maintaining process optimization through natural cycling.
Solution Approach 2:
The tidal flooding creates periodic alternation between aerobic and anoxic conditions in the same facility. During flooding, oxygen is supplied for nitrification; during drainage, anoxic conditions prevail for denitrification. This temporal separation allows both processes to occur optimally in the same space.
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 process effectively eliminates up to 90% of nitrogenous pollutants and 95% of BOD5, reducing operational costs and energy consumption, while integrating seamlessly into the landscape and minimizing odor release.
Implementation Method 1
the oxygen required for treatment is provided by exchanges with the atmosphere... the reeds are planted in a porous substrate... the root development of the reeds forms a root bed within the substrate
Implementation Method 2
The organic nitrogen present in the wastewater is transformed into ammoniacal nitrogen... The two stages of nitrification and denitrification... from the ammoniacal nitrogen, gaseous nitrogen is released
Implementation Method 3
the operating conditions of the installation are modified to promote the direct reduction of nitrites into gaseous nitrogen, under the action of heterotrophic bacteria, in an anoxic environment
Implementation Method 4
a filter planted with reeds with vertical flow... the flow of the effluents in the filter planted with reeds takes place under the simple action of gravity
Data Source
Figure 1
Figure 2
AI summary
The treatment of effluents comprises a biological pretreatment of the effluents using bacterial bed, and a biological treatment of nitrification-denitrification of a clarification sludge obtained at an exit of the bacterial bed using vertical-flow reed bed filter. The clarification sludge has a carbon source for nitrification and denitrification. In permanent operating regime, a nitrification-denitrification filter comprises a lower inundated zone and an upper inundated zone. The treatment of effluents comprises a biological pretreatment of the effluents using bacterial bed, and a biological treatment of nitrification-denitrification of a clarification sludge obtained at an exit of the bacterial bed using vertical-flow reed bed filter. The clarification sludge has a carbon source for nitrification and denitrification. In permanent operating regime, a nitrification-denitrification filter comprises a lower inundated zone and an upper inundated zone, on which a biological anaerobic denitrification treatment and a biological aerobic denitrification treatment, are carried out respectively. The height of the inundated zone is greater than or equal to the height of its non-inundated zone. An independent claim is included for a device for waste processing.