AOB Granules for Shortcut Nitrogen Removal
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Solution Overview
Problem
Conventional nitrogen removal processes in wastewater treatment require significant oxygen and organic matter, leading to high operational costs and inefficiencies, particularly in achieving stable partial nitritation using ammonium oxidation bacteria (AOB) granules.
Innovation Solution
A wastewater treatment apparatus incorporating an ANAMMOX process and AOB granules, with a partial nitritation tank, granule recovery tank, and AOB granulation tank, where AOB granules are produced and reused to stabilize partial nitritation and reduce oxygen and organic matter consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional nitrification and denitrification processes are used for nitrogen removal, then nitrogen can be removed from wastewater, but significant amounts of oxygen and organic matter are consumed, leading to high operational costs
Solution Approach 1:
The patent extracts and separates the nitrogen removal process into two distinct biological pathways: partial nitritation (ammonia to nitrite) and ANAMMOX (nitrite to nitrogen gas). By taking out the traditional denitrification step that requires organic carbon and replacing it with ANAMMOX bacteria that use nitrite as electron acceptor, the system eliminates the need for external organic matter addition while reducing oxygen consumption by approximately 60% compared to conventional nitrification-denitrification processes
Solution Approach 2:
The patent changes the chemical parameters of the system by maintaining specific dissolved oxygen concentrations (0.5-2.0 mg/L) in the nitritation tank to favor partial nitritation rather than complete nitrification, and by controlling the carbon-to-nitrogen ratio in the ANAMMOX tank to enable anaerobic ammonium oxidation. These parameter changes enable the transition from oxygen-intensive conventional processes to the energy-efficient shortcut nitrogen removal pathway
2Quantity of substance
If AOB granules are used to achieve stable partial nitritation, then nitrogen removal efficiency improves, but forming and maintaining stable AOB granules is difficult and time-consuming
Solution Approach 1:
The patent applies preliminary action by pre-forming AOB granules in a dedicated granulation tank before introducing them to the main treatment system. This pre-cultivation approach allows the AOB granules to develop stable structures and high ammonia oxidation activity in advance, so that when they are transferred to the nitritation tank, they immediately provide stable partial nitritation performance without requiring lengthy acclimation periods
Solution Approach 2:
The AOB granules are designed to be self-sustaining and self-replicating within the system. Once established in the granulation tank, the AOB granules continuously reproduce and maintain themselves through endogenous growth, eliminating the need for continuous external inoculation or manual intervention. The granules also self-regulate their population density and activity levels based on the substrate availability in the wastewater stream
3Quantity of substance
If side stream from sludge treatment is used as carbon source for AOB granule formation, then external carbon addition costs are reduced, but the side stream contains high nitrogen and phosphor loads requiring proper treatment
Solution Approach 1:
The patent converts the harmful high nitrogen and phosphor loads in the side stream into beneficial resources for AOB granule formation and maintenance. The side stream is introduced into the granulation tank where AOB granules utilize the organic carbon compounds present in the side stream for growth and granule formation. Simultaneously, the AOB granules consume and transform the nitrogen compounds through partial nitritation, and the phosphor is incorporated into the granule biomass. This approach transforms the side stream from a waste product requiring treatment into a valuable substrate that supports granule development while reducing the nitrogen and phosphor loads
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 apparatus achieves stable partial nitritation and efficient nitrogen removal by stabilizing AOB granules, saving 100% organic matter and 60% oxygen compared to conventional methods, while maintaining high-purity AOB dominance.
Implementation Method 1
partial nitritation transforms ammonia nitrogen into nitrite nitrogen under an aerobic condition using oxidation of digestion bacterial, e.g., Nitrosomonas or Nitrobacter
Implementation Method 2
ANAMMOX uses nitrite nitrogen as an electron donor under an anaerobic condition, thereby transforming ammonia nitrogen into nitrogen gas
Implementation Method 3
forming AOB granules using a side stream produced in a sludge treatment process
Data Source
AI summary
The present invention relates to a wastewater treatment apparatus for shortcut nitrogen removal using anaerobic ammonium oxidation (ANAMMOX) and partial nitritation using ammonium oxidizing bacteria (AOB) granules. High-purity AOB granules are formed by means of AOB predominance using a side stream generated during a sludge treatment process. Moreover, the formed AOB granules are supplied to a partial nitritation tank (130) of a main treatment process and thus the partial nitritation is efficiently performed and nitrogen is quickly removed, and thus oxygen and an organic material is reduced compared to an existing method.