Integrated Waste Digester for Biogas and Compost
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Solution Overview
Problem
Current solid waste treatment methods face challenges in efficiently decomposing organic matter into biogas and compost, particularly due to limitations in solids handling and the need for separate stages with inoculation and heating, which can lead to inefficiencies and increased energy consumption.
Innovation Solution
A system that integrates hydrolysis, methanogenesis, and composting stages in a single process module, where organic waste is initially loaded into a chamber, subjected to anaerobic conditions for methane extraction, followed by aerobic composting without moving the solid fraction, utilizing a closed system with recirculation of percolate liquid and air ventilation to produce high-methane biogas and stable compost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solid waste is treated using conventional two-stage anaerobic digestion methods with separate reactors, then biogas production is achieved, but solids handling requirements increase and process complexity increases
Solution Approach 1:
The patent combines the hydrolysis reactor and methanogenesis reactor into a single integrated digester vessel. The system uses internal separation where percolate liquid flows to a separate methanogenesis zone while solid waste remains in the hydrolysis zone, eliminating the need for multiple external reactors and complex solids handling infrastructure.
Solution Approach 2:
The single digester is divided into functional zones: a hydrolysis zone for solid waste breakdown and a methanogenesis zone for biogas production. Percolate liquid is separated and routed to the methanogenesis zone, while solid fraction remains in the hydrolysis zone, achieving functional segmentation without physical reactor separation.
2Productivity
If solid waste is moved between different stages of treatment, then processing can be completed, but solids handling requirements and energy consumption increase
Solution Approach 1:
Both hydrolysis and methanogenesis stages occur within the same digester vessel, eliminating the need to transport solid waste between reactors. The system processes waste in-place through sequential biological stages, reducing mechanical handling and energy requirements.
3Speed
If inoculation and heating are used to accelerate decomposition, then decomposition rate increases, but energy consumption and process complexity increase
Solution Approach 1:
The system relies on natural microbial populations already present in the waste to perform decomposition without external inoculation. The exothermic nature of decomposition provides self-heating that maintains optimal temperatures for microbial activity, eliminating the need for external energy inputs for inoculation or heating.
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 eliminates the need for solids handling between stages, achieves high methane content in biogas, reduces contaminants, and ensures energy efficiency by maintaining anaerobic conditions, allowing for self-sustaining processes without inoculation or heating, while producing pathogen-free compost.
Implementation Method 1
The percolate liquid is pumped into a biogas reactor tank in which methane and/or other biogases are produced
Implementation Method 2
The percolate is pumped into a biogas reactor tank in which methane and/or other biogases are produced
Implementation Method 3
an aerobic composting process begins in the same chamber. The organic waste remains in place and oxygen (e.g., in air) is forced into the chamber for an additional period of time
Implementation Method 4
utilizing a closed system with recirculation of percolate liquid
Implementation Method 5
oxygen (e.g., in air) is forced into the chamber for an additional period of time
Data Source
AI summary
This invention relates generally to systems and methods for digestion of solid waste that simplify solids handling. In certain embodiments, anaerobic methane extraction takes place for a period of time (e.g., from 1 to 4 weeks), after which an aerobic composting process begins in the same chamber. The organic waste remains in place and oxygen (e.g., in air) is forced into the chamber for an additional period of time (e.g., from 2 to 4 weeks). At the conclusion of the aerobic phase, the process yields a rough compost product that is stable and pathogen free. The rough compost can be further processed and blended to create high value engineered soils.