Landfill Leachate Treatment via Coagulation and Reverse Osmosis
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Solution Overview
Problem
Current methods for treating landfill leachate are inefficient and costly due to inhibition of activated sludge by high ammonia nitrogen compounds, requiring pre-removal and resulting in secondary pollution, and are characterized by high equipment and operating costs associated with complex biological degradation processes.
Innovation Solution
A method involving coagulative settling, three-stage filtration using specific cartridge filters, and reverse osmosis followed by treatment with chlorine-based oxidants to reduce contaminants, including ammonia nitrogen compounds, with a focus on physical and chemical processes for efficient contaminant removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If biological degradation methods (activated sludge) are used to treat landfill leachate, then organic substances can be degraded, but the high ammonia nitrogen compounds inhibit the leachate-degrading activity of activated sludge
Solution Approach 1:
The patent applies preliminary action by removing ammonia nitrogen compounds through coagulative settling before the biological degradation stage. This pre-treatment step eliminates the inhibitory effect of ammonia nitrogen on activated sludge, ensuring the biological degradation process can proceed efficiently without interference.
2Productivity
If pre-removal of ammonia nitrogen compounds is performed, then activated sludge degradation efficiency is improved, but ammonia nitrogen compounds are discharged directly into the atmosphere causing secondary pollution
Solution Approach 1:
The patent changes the parameter of ammonia nitrogen removal by using coagulative settling instead of traditional methods that release ammonia into the atmosphere. This physical-chemical process transforms ammonia nitrogen from a gaseous emission into a solid precipitate that can be safely disposed of, eliminating secondary pollution while maintaining degradation efficiency.
3Manufacturing precision
If Membrane Bioreactor and Continuous Membrane Filtration methods are used, then purification can be achieved, but equipment and operating costs are high due to complexity and cost of hollow fiber membranes
Solution Approach 1:
The patent replaces expensive, complex hollow fiber membranes with simpler, more economical filtration systems. The coagulative settling process combined with basic filtration achieves comparable purification quality without the high equipment costs and operational complexity associated with membrane bioreactors and continuous membrane filtration systems.
4Productivity
If biological degradation processes are used, then organic substances can be degraded, but the processes are inefficient and expensive
Solution Approach 1:
The patent segments the treatment process into distinct stages: coagulative settling for ammonia nitrogen removal, followed by biological degradation for organic substance decomposition. This segmentation allows each process to operate optimally without interference, improving overall efficiency and reducing costs compared to integrated biological systems that must accommodate multiple contaminants simultaneously.
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 method significantly reduces contaminants, achieving 99% removal of organic substances, heavy metals, and COD/BOD, while being cost-effective and simpler to maintain than existing biological methods, meeting discharge and consumption standards with reduced ammonia nitrogen levels.
Implementation Method 1
coagulatively settling of landfill leachate to produce a supernatant liquid
Implementation Method 2
suspended solids, such as sludge and other solid particles in landfill leachate, are settled
Implementation Method 3
filtering the first filtered liquid in a reverse osmosis apparatus to produce a second filtered liquid
Implementation Method 4
treating said second filtered liquid with a chlorine-based oxidant
Data Source
AI summary
Methods for treating landfill leachate taught herein comprise: (a) coagulatively settling leachate; (b) filtering the resultant supernatant liquid through multistage cartridges; (c) filtering the filtered liquid by reverse osmosis; and (d) treating the resultant liquid with chlorine-based oxidant. These methods provide the advantages of efficient wastewater treatment, compact equipment size, short process flow, and low startup and operational costs.