Mixed Waste Processing System Using Steam and Optical Sorting

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Solution Overview

Problem

Current recycling programs face challenges such as high labor and capital costs, complex curbside program restrictions, and low participation due to source separation requirements, leading to significant amounts of recyclable materials being landfilled instead of recycled, particularly for materials like plastics and electronics.

Innovation Solution

A waste processing system that utilizes existing MSW collection infrastructure to efficiently separate and recover recyclable materials from mixed household waste, including film plastics, textiles, and electronics, without the need for initial source separation, using a combination of shredding, screening, steam processing, and advanced separation technologies like air/density separation and NIR optical sorting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If source separated curbside recycling programs are implemented, then recyclable materials can be collected, but labor and capital costs increase significantly

Engineering Contradiction:

Improverecyclable materials collectionVSAvoidprogram complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of separating recyclables at the source (curbside), the patent inverts the approach by collecting mixed waste and separating recyclables at the processing facility using automated technologies like optical sorters and density separators

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces manual source separation with automated mechanical and optical separation systems at the processing facility, including near-infrared scanners, eddy current separators, and vibratory sorting equipment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If source separated curbside recycling programs are implemented, then recyclable materials can be collected, but participation decreases due to complexity

Engineering Contradiction:

Improverecyclable materials collectionVSAvoidconsumer participation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent eliminates the need for consumer separation efforts by inverting the process: consumers deposit mixed waste conveniently, and automated facilities perform the separation, making participation simple and accessible

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The automated processing facility performs self-service separation using optical scanners, density separators, and mechanical sorters that automatically identify and separate recyclable materials without human intervention

Inventive Principle:

Principle #25Self-service

3Reliability

If curbside recycling programs are operated, then recyclable materials can be collected, but operating costs increase

Engineering Contradiction:

Improverecyclable materials collectionVSAvoidoperating cost

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent combines waste collection with recyclable recovery in a single integrated process, eliminating separate curbside recycling collection routes and consolidating operations at centralized processing facilities

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the operational parameters from low-volume source-separated collection to high-volume mixed waste processing with automated separation, improving economies of scale and reducing per-ton processing costs

Inventive Principle:

Principle #35Parameter changes

4Productivity

If mixed waste is processed without source separation, then recycling recovery is improved, but separation difficulty increases

Engineering Contradiction:

Improverecycling recoveryVSAvoidmaterial separation

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs optical scanners, near-infrared detectors, and automated sensing systems to identify and sort materials based on their physical and chemical properties, replacing manual separation with sophisticated detection technologies

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent segments the mixed waste stream into multiple fractions using sequential separation stages: density separation for plastics, optical sorting for paper and containers, and mechanical sorting for metals, making complex separation manageable through systematic division

Inventive Principle:

Principle #1Segmentation

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

The system enables the recovery of nearly all recyclable materials, reducing landfill waste, lowering recycling costs, and creating new revenue streams by processing mixed waste streams efficiently, including low-value materials typically ignored in curbside programs, while promoting sustainable recycling and decarbonization efforts.

Implementation Method 1

An air/density separation device downstream of the steam processor separates materials from the waste stream

Methodology Applied

Scientific EffectDensity separation: Density Gradient

Implementation Method 2

NIR optical sorting

Methodology Applied

Scientific EffectNear-infrared detection: Absorption Spectroscopy

Data Source

PatentUS20230405651A1System and method for processing of mixed solid waste to recover recyclable materials

Publication Date: 2023.12.21 ALFORD PAUL W

AI summary

A system for recovering recyclable materials from mixed waste is provided. The system processes existing municipal solid waste collections to recover recyclable materials from the waste. The system uses various separation processes sequenced with a rotating, horizontal constant-flow steam based waste processing vessel to efficiently separate high value materials such as metals and rigid plastics while additionally separating low value plastics and post-consumer commodities. The system reduces landfill load and operational costs while simultaneously providing the reduction of carbon emissions achieved with recycling post-consumer commodities.