Ammonia Stripping and Absorption for Zootechnical Waste Purification
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Solution Overview
Problem
Current methods for managing zootechnical waste, such as biological nitrification/denitrification and ammonia stripping/absorption, face inefficiencies and environmental concerns, particularly in areas lacking sufficient agricultural land, and require significant energy and chemical additives.
Innovation Solution
A process combining batch ammonia stripping and continuous absorption, utilizing a cogeneration system and solid/liquid separation, which eliminates the need for chemical additives and reduces energy consumption by leveraging heat from cogeneration and anaerobic digestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If biological nitrification/denitrification is used to manage zootechnical waste, then nitrogen transformation occurs, but significant electricity consumption and loss of bioavailable nitrogen occur
Solution Approach 1:
The patent replaces the biological nitrification/denitrification system with a thermal-chemical system consisting of ammonia stripping followed by absorption. Instead of using biological processes that require aeration (high electricity consumption), the invention uses heating to strip ammonia from the waste stream, then absorbs it into acid solutions to produce ammonium salts. This substitution of biological mechanisms with thermal-chemical processes eliminates the need for significant electricity input while maintaining nitrogen management effectiveness.
Solution Approach 2:
The patent changes the operational parameters from biological conditions (aeration, specific temperature ranges for microbes) to thermal-chemical parameters (higher temperatures for stripping, controlled pH for absorption). By raising the temperature to facilitate ammonia stripping and then controlling the pH of absorption solutions, the system transforms nitrogen from a biological process requiring continuous energy input to a thermal process that can be more efficiently managed and that produces valuable ammonium salt products.
2Loss of substance
If ammonia stripping/absorption is used to recover nitrogen, then ammonium salts are produced, but dependence on temperature and pH control remains
Solution Approach 1:
The patent implements feedback control systems for both temperature and pH parameters. Temperature sensors monitor the stripping process and adjust heating input to maintain optimal stripping conditions. pH sensors in the absorption tanks provide feedback to control the acid addition rates, ensuring efficient ammonium salt formation. This feedback mechanism automates the complex parameter control, reducing manual intervention while maintaining high nitrogen recovery efficiency.
Solution Approach 2:
The patent uses pH-adjusting agents and buffering systems as intermediaries to simplify temperature and pH control. By introducing substances that buffer pH changes or mediate the acid-base reactions, the system reduces the complexity of direct pH control. These intermediaries act as buffers that stabilize the chemical environment, making the overall process more robust and easier to control despite the inherent complexity of ammonia-stripping/absorption chemistry.
3Quantity of substance
If solid/liquid separation with centrifugal decanters is used to increase inorganic-reduced nitrogen ratio, then separation efficiency increases, but energy consumption and operational complexity increase
Solution Approach 1:
The patent employs dynamic solid/liquid separation systems that can adjust their operational characteristics based on feed composition and desired output quality. Rather than using high-energy centrifugal decanters that operate at constant high speeds, the invention uses adjustable separation mechanisms that can modulate their intensity. This dynamic approach allows the system to achieve the necessary inorganic-reduced nitrogen ratio while consuming less energy by adapting separation intensity to actual process needs rather than operating at maximum capacity continuously.
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 achieves high ammonia removal efficiency with reduced energy and chemical usage, producing a valorizable ammonium salt product while minimizing environmental impact and pathogenic microorganisms, and requires minimal maintenance.
Implementation Method 1
a) digestion, ... operating under anaerobic conditions, this mixture mainly includes methane and carbon dioxide, the so-called biogas
Implementation Method 2
c) stripping, ... Pre-heating and a slight supply of air are maintained throughout the loading period
Implementation Method 3
a slight supply of air are maintained throughout the loading period
Implementation Method 4
d) absorption of ammonia, ... the aeriform flow coming from the stripping tanks is washed in countercurrent with an acid solution, inside a filling column (scrubber)
Implementation Method 5
e) cogeneration, ... The gas is sent to a cogeneration system
Implementation Method 6
The heat thus recovered is used for the operation of the digesters and for the operation of the ammonia removal plant
Data Source
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AI summary
The present invention relates to a process for the purification of waste from zootechnical sources or from small agri-food companies.