Biological Filtration Process for Nitrogen Removal with Reduced Aeration
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Solution Overview
Problem
Current biological wastewater treatment processes for nitrogen pollution are costly due to high oxygen and exogenous organic carbon consumption, and they struggle to maintain optimal deammonification conditions without additional adjustments.
Innovation Solution
A biological filtration process that includes a nitritation and filtration step followed by a deammonification and denitrification step, where the stoichiometry of the Anammox reaction is adjusted using treated water to optimize conditions without external carbon sources, utilizing autotrophic and heterotrophic bacteria in aerated and non-aerated reactors respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrification-denitrification process is used to reduce nitrogen pollution, then nitrogen removal effectiveness is improved, but oxygen consumption and treatment cost increase
Solution Approach 1:
The process is divided into three distinct stages: nitritation (ammonia to nitrite), filtration, and deammonification (nitrite + ammonia to nitrogen gas). This segmentation allows each stage to be optimized independently, with the nitritation stage producing nitrites that are then consumed in the deammonification stage, reducing the need for external carbon sources and lowering overall oxygen consumption compared to conventional nitrification-denitrification
Solution Approach 2:
The process changes the nitrogen transformation parameters by stopping at nitrite production in the first stage (rather than complete nitrification to nitrate), and then using these nitrites in the deammonification stage. This parameter change from full nitrification to partial nitritation followed by deammonification reduces oxygen consumption while maintaining nitrogen removal effectiveness
2Reliability
If nitrification-denitrification process is used to reduce nitrogen pollution, then nitrogen removal effectiveness is improved, but treatment cost increases due to exogenous organic carbon source requirements
Solution Approach 1:
The system uses itself to provide the carbon source needed for deammonification. The heterotrophic bacteria in the deammonification stage use organic matter present in the wastewater itself as their carbon source, eliminating the need for external carbon addition. This self-service approach maintains nitrogen removal effectiveness while avoiding the costs associated with exogenous organic carbon sources
Solution Approach 2:
The process converts the potentially harmful organic pollution in wastewater into a beneficial resource. The organic matter that would normally be considered waste or pollution is utilized as the carbon source for heterotrophic bacteria in the deammonification stage, transforming a harmful substance into a useful resource that drives nitrogen removal without requiring external carbon addition
3Use of energy by moving object
If nitritation process is used to reduce oxygen consumption, then oxygen consumption is reduced, but nitrate production occurs which requires additional treatment
Solution Approach 1:
The process implements feedback control by monitoring the nitrite to ammoniacal nitrogen ratio and using this information to adjust operations. The ratio measurement provides feedback on the nitritation stage performance, allowing operators to optimize the balance between nitrite production and consumption in the deammonification stage, thereby controlling nitrate formation while maintaining low oxygen consumption
Solution Approach 2:
The process dynamically balances nitrite production and consumption by adjusting operational parameters based on the nitrite to ammoniacal nitrogen ratio. This dynamic control allows the system to adapt to varying influent conditions, maintaining optimal nitritation-deammonification balance and preventing nitrate accumulation while keeping oxygen consumption low
4Use of energy by moving object
If deammonification is performed without aeration, then oxygen consumption is reduced, but stoichiometry optimization requires complex adjustments
Solution Approach 1:
The process replaces complex mechanical control systems with a simpler chemical parameter-based control approach. Instead of using complex automated systems to adjust stoichiometry in real-time, the invention uses the measurable nitrite to ammoniacal nitrogen ratio as a straightforward indicator to guide operational adjustments, simplifying the control mechanism while maintaining deammonification effectiveness without aeration
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 reduces oxygen and carbon consumption by up to 55% and 100% respectively, while maintaining effective nitrogen removal, ensuring treated water meets health and regulatory standards without the need for exogenous carbon supplies.
Implementation Method 1
ammonia oxidising bacteria) capable of converting the ammoniacal nitrogen (NH4+) into nitrites (NO2−)
Implementation Method 2
Anammox bacteria are autotrophic, and capable of converting the nitrites and the ammoniacal nitrogen into gaseous nitrogen (N2)
Implementation Method 3
denitrifying biomass capable of reducing the nitrates into nitrites, then into molecular gaseous nitrogen (dinitrogen, N2)
Implementation Method 4
biological filtration tank performs biological filtration as a pretreatment process of influent wastewater and removes solids and organic matters
Data Source
AI summary
The present invention relates to a biological filtration process for water loaded with nitrogenous pollutants in order to reduce the global nitrogen content of said water, characterised in that it comprises a first step of nitritation and filtration carried out in a first aerated biological reactor, a second step of deammonification, denitrification and filtration carried out in a second non-aerated biological reactor, and a step of evaluation of the ratio of the nitrite content to the ammoniacal nitrogen content of the water at the outlet of the first reactor. When this ratio is greater than a predetermined stoichiometry value, the process according to the invention comprises a step of addition of water to be treated to the water originating from the first reactor so as to obtain, at the inlet of the second reactor, a mixture having a ratio of the nitrite content to the ammoniacal nitrogen content that is close to the stoichiometric ratio of the Anammox reaction.