Landfill Leachate Nitrogen Removal via Partial Nitrification
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Solution Overview
Problem
Current wastewater treatment methods for ammonium-rich waste, such as landfill leachate, face challenges including high energy requirements, excess sludge production, and insufficient organic carbon sources for denitrification, particularly in single-reactor systems and fixed-bed processes.
Innovation Solution
A two-stage process where ammonium in wastewater is partially oxidized to nitrite at specific temperature and oxygen levels in the first stage, followed by anaerobic conversion to nitrogen in activated carbon fixed bed reactors without oxygen, utilizing Planctomycetes bacteria, which eliminates the need for additional carbon sources and reduces sludge production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If complete nitrification is performed to remove ammonium, then nitrogen removal is achieved, but high energy requirements and excess sludge production occur
Solution Approach 1:
The nitrogen removal process is segmented into two distinct stages: partial nitrification (ammonium to nitrite) followed by anammox (nitrite and ammonium to nitrogen gas). This segmentation allows the system to avoid complete nitrification to nitrate, thereby reducing aeration energy requirements while still achieving effective nitrogen removal.
Solution Approach 2:
The process changes key operational parameters: oxygen concentration is controlled to enable partial nitrification but prevent complete nitrification, and the system transitions to anaerobic conditions for the anammox stage. These parameter changes allow nitrogen removal with lower energy consumption.
2Quantity of substance
If complete nitrification is performed to remove ammonium, then nitrogen removal is achieved, but excess sludge production increases
Solution Approach 1:
By segmenting the nitrogen removal into partial nitrification and anammox stages, the system avoids the extensive biomass growth associated with complete nitrification. The anammox process inherently produces less sludge because it is a direct conversion process rather than a growth-based process.
3Quantity of substance
If organic carbon sources are added for denitrification, then nitrogen removal is enhanced, but process complexity and cost increase
Solution Approach 1:
The system uses the ammonium present in the wastewater itself as the carbon source for the anammox process, eliminating the need for external carbon source addition. The ammonium serves dual purposes: as the nitrogen to be removed and as the electron donor for the anammox reaction.
4Device complexity
If single-reactor systems are used for nitrogen removal, then device complexity is reduced, but insufficient organic carbon sources for denitrification occur
Solution Approach 1:
The system changes the fundamental parameter of oxygen availability, creating alternating aerobic (partial nitrification) and anaerobic (anammox) conditions within the reactor system. This parameter change enables the process to proceed without requiring external carbon sources that would be necessary for traditional denitrification.
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 approach results in energy savings, minimal excess sludge generation, and efficient nitrogen removal without requiring degradable carbon, optimizing the process by controlling ammonium and oxygen levels and using activated carbon reactors for anaerobic ammonium oxidation.
Implementation Method 1
the ammonium contained in the wastewater is partially oxidized and then converted into gaseous nitrogen
Implementation Method 2
in a second stage with the exclusion of oxygen in one or several activated carbon fixed bed reactors to form nitrogen
Data Source
AI summary
The method for the treatment of landfill water with high nitrogen and low 5-day biochemical oxygen demand in a two-stage process, comprises mixing the landfill water with nitrifying activated sludge in a first step, oxidizing ammonium contained in the landfill water only in a part to nitrite, and reacting nitrite and ammonium contained in the aqueous phase separated from the activated sludge under exclusion of oxygen in activated carbon fixed bed reactor to molecular nitrogen in a second step. The activated carbon fixed bed reactors turned in rows are flowed one after the other. The method for the treatment of landfill water with high nitrogen and low 5-day biochemical oxygen demand in a two-stage process, comprises mixing the landfill water with nitrifying activated sludge in a first step, oxidizing ammonium contained in the landfill water only in a part to nitrite, and reacting nitrite and ammonium contained in the aqueous phase separated from the activated sludge under exclusion of oxygen in activated carbon fixed bed reactor to molecular nitrogen in a second step. The activated carbon fixed bed reactors turned in rows are flowed one after the other. The ammonium content is adjusted in the first step, which is operated under microaerophilic condition. The oxygen content adjusted in the first step is 0.01-0.4 mg/l. The ratio of nitrogen content in the ammonium and in the nitrogen dioxide of 1:1.1 is adjusted in the flow of the first step over a process control. In the first step, temperature is adjusted to 28-39[deg] C. The addition to the second step is same as the addition to the activated carbon fixed bed reactors free from dissolved oxygen. The activated carbon is inoculated to begin the process with planctomycetes containing granular. The ratio of the used activated carbon and the granular is 50:1 related to the volume. The internal surface of the used activated carbon is 600-1800 m 2>/g. The first and the second step are separated through a membrane filtration. An independent claim is included for a device for the treatment of landfill water with high nitrogen and low 5-day biochemical oxygen demand in a two-stage process.