Two-Stage Composting Process for Heterogeneous Waste

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Solution Overview

Problem

Current industrial composting processes face challenges in efficiently sorting and processing heterogeneous waste mixtures containing both biodegradable and non-biodegradable materials, leading to high costs, environmental pollution, and inefficient waste recovery due to the need for preliminary sorting and infrastructure, which often results in a significant portion of waste being incinerated or buried.

Innovation Solution

A process involving two composting cycles separated by a drying stage, where a mixture of waste is first composted to produce pre-composted waste, then dried and separated into heavy and light fractions, with the light fraction undergoing a second composting cycle to produce refined compost, while the heavy fraction is recycled or processed differently, reducing the need for preliminary sorting and infrastructure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If preliminary sorting of waste is performed before composting, then the quality of compost is improved, but the cost and complexity of the process increases

Engineering Contradiction:
Improvecompost qualityVSAvoidsorting infrastructure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing a preliminary composting cycle on the entire waste mixture before separation. This pre-composting step stabilizes the organic matter and reduces its moisture content, making subsequent separation into heavy and light fractions more effective. The preliminary action prepares the waste for easier processing in later stages without requiring complex preliminary sorting infrastructure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by altering the physical state of waste through drying and composting processes. By changing the moisture content and density parameters of the waste during the composting cycles, the material becomes suitable for separation by density (heavy vs. light fractions). This parameter transformation enables simple gravitational separation without complex sorting equipment.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If complete sorting of waste is performed, then the amount of compostable material is maximized, but the time and resource consumption increases

Engineering Contradiction:
Improvecompostable material recoveryVSAvoidprocessing time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies segmentation by dividing the composting process into two distinct cycles: a first composting cycle that processes the entire mixture, followed by separation into heavy and light fractions, and then a second composting cycle that processes only the light fraction. This segmented approach allows selective processing of the most compostable materials while avoiding the time-consuming task of completely sorting the entire waste stream beforehand.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the most compostable organic matter through the separation process between the two composting cycles. By removing the heavy fraction (containing inert materials, metals, and dense organics) after the first composting cycle, the process extracts and processes only the valuable light fraction in the second cycle, maximizing compostable material recovery without requiring complete initial sorting.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If heterogeneous waste mixture is processed directly, then the infrastructure requirement is reduced, but the efficiency of composting decreases

Engineering Contradiction:
Improveinfrastructure requirementVSAvoidcomposting efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies periodic action by implementing two sequential composting cycles separated by a drying and separation stage. The first composting cycle processes the heterogeneous mixture, followed by drying and separation into heavy and light fractions. The second composting cycle then processes the light fraction. This periodic repetition of composting-drying-separating allows the system to handle heterogeneous waste efficiently while maintaining high composting productivity through controlled, staged processing.

Inventive Principle:
Principle #19Periodic action

4Ease of manufacture

If manual sorting by households is performed, then the initial sorting cost is reduced, but the reliability of waste separation is low

Engineering Contradiction:
Improvecollection costVSAvoidsorting accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies self-service by designing a system where the waste mixture automatically separates into heavy and light fractions through density-based gravitational separation during the drying process. The physical properties of the waste materials cause them to self-separate without requiring manual intervention or complex mechanical sorting equipment. This self-service mechanism ensures reliable separation while keeping infrastructure requirements and collection costs low.

Inventive Principle:
Principle #25Self-service

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 allows for the efficient recovery and refinement of biodegradable waste into high-quality compost with reduced environmental impact and lower resource and energy consumption, simplifying waste collection and treatment processes, and enabling a more automated and cost-effective treatment method.

Implementation Method 1

at least one drying bay for the pre-composted waste mixture, allowing a mixture of dried waste to be obtained

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

means for separating the dried waste mixture into at least a portion of heavy waste and a portion of light waste, the portion of heavy waste being substantially formed by waste with a higher density than the waste in the portion of light waste

Methodology Applied
Scientific EffectDensity separation: Density Gradient

Implementation Method 3

at least one first composting bay allowing the waste mixture to undergo a first composting cycle so as to compost at least part of the biodegradable waste from said waste mixture

Methodology Applied
Scientific EffectBiological decomposition: Decomposition (biological)

Data Source

PatentEP3145636B1Method for treating a mixture of waste, having two composting cycles
Publication Date: 2022.01.26 FINANCE DEV ENVIRONNEMENT CHARREYRE FIDEC
  • EP3145636B1 patent drawingFigure 1
  • EP3145636B1 patent drawingFigure 2
  • EP3145636B1 patent drawingFigure 3~4

AI summary

- The invention relates to an installation and a method for treating a mixture of waste (4) comprising biodegradable waste, the method being characterized in that it comprises the following successive steps: - Step A: the mixture of waste (4) is subjected to a first composting cycle so as to obtain a mixture of pre-composted waste (4), - Step B: the mixture of pre-composted waste (4) is dried in order to obtain a mixture of dried waste (4), - Step C: the mixture of dried waste (4) is separated into at least one portion of heavy waste (14) and one portion of light waste (13), - Step D: the portion of light waste (13) is subjected to a second composting cycle so as to obtain a mixture of refined waste (4; 20). - Treatment of biodegradable waste.