The Methodology

STREP applies a user-centred and iterative design approach:

Iterative loops of development, testing, and review
Pilot-scale validation of system performance
Scalability and commercial viability evaluation

Detection & Disintegration

AI-powered sensors identify and remove accessories (zippers, prints, trims) automatically, reducing cost and manual labor.

Design & Assembly

Requirements are collected to optimize sorting, disassembly, and recycling outcomes (capacity, accuracy, automation, and resource use)

Recycling Technologies

Textile waste is treated through a sequence of dissolution, glycolysis, enzymatic hydrolysis, hydrothermal liquefaction, and pyrolysis, optimized for maximum fibre recovery and minimal degradation.

Traceability & Product Identification

Smart sensors generate batch-level data; traceability systems ensure that all recycled outputs are linked to their source materials

Main Innovations

AI + NIR/X-ray/machine vision sorting

Automated accessory removal with sensor fusion

Enzymatic recycling + SCCO₂ purification

Digital twins & DLT for traceability

Data-driven optimization from lab to pilot

Pathway to Sustainability

Textile input

Smart sorting & accessory removal

Chemical/enzyme recycling

Fibre recovery

Repolymerization

New yarn/textile products

STREP Methodologies

Automated Accessory Removal

To improve textile recycling, STREP is developing a cost-efficient, automated system to detect and remove accessories like buttons, zippers, prints, and reflective tapes from textile waste.

The process includes:

Preparation: Cutting garments into optimally sized patches for efficient sorting.
Detection: Using sensors (e.g. NIR, X-ray, vision) and smart algorithms to identify accessories or contaminants.
Removal: Automatically sorting out contaminated patches based on detection data.
Traceability: Integrating with MES systems to track each batch and support process optimization.

Chemical Recycling Technologies

STREP develops and integrates multiple chemical recycling methods to handle non-reusable textile waste, ensuring high resource recovery and sustainability:

Dissolution: A gentle process that preserves natural fibres in polycotton blends. Solvents are recovered via membrane filtration and distillation. Optimised through lab and pilot-scale trials.
Glycolysis/Solvolysis: Applied to low-grade PET and elastane. Yields monomers for repolymerisation into new fibres. Process parameters and purification steps are refined in lab tests.
Enzymatic Recycling: Uses enzymes to break down synthetic fibres in blends. PET is depolymerised, followed by hydrothermal treatment of cotton to produce bio-crude.
Pyrolysis: Treats waste with high plastic or accessory content, producing oil and biochar. Lab studies focus on process optimisation and product purification.
Hydrothermal Liquefaction (HTL): Converts waste to bio-crude and biochar. CIRCE will optimise parameters and valorise the aqueous phase via advanced treatments.
Supercritical CO₂ (SCCO₂): Used for pretreatment or purification to enhance glycol reuse and reduce impurities.
Electrospinning: Produces fibre mats from recycled polymers to test material properties and support enzymatic depolymerisation.

Characterisation & Separation of Valuable Chemicals

STREP addresses the challenge of extracting valuable chemicals from complex recycled textile products, especially from composite materials.

Analysis: Advanced analytical tools (GC×GC-HRMS, IR, NMR) are used to identify and characterise unknown compounds in liquids from pyrolysis, solvolysis, and hydrolysis.
Distillation: Standard or vacuum distillation separates complex liquids into 4–6 simpler fractions based on boiling points, enabling easier analysis and recovery.
Preparative Chromatography: Used to purify and isolate valuable chemicals from complex mixtures like pyrolysis oils, ensuring sufficient purity for reuse.
Equipment Setup: UJEP will install a full system for preparative chromatography, including FTIR with heating stage and textile testing rigs.
Goal: To optimise recovery and purification of valuable compounds from chemically recycled textile waste, supporting a circular economy.

Fibre Length Measurement for Mechanical Recycling

STREP aims to enable real-time fibre length measurement to improve mechanical recycling efficiency.

Current Limitations: Traditional methods (AFIS, HVI) require manual sample prep, slowing down the process.
Approach 1 – Online Measurement: A VIS/NIR camera system will be installed at the fibre-opening machine. Optical characteristics of cotton, polycotton, PET, and nylon will be analysed using machine learning (SVM, PCA, etc.) and deep learning (YOLO, SAM) to estimate fibre length directly from images.
Approach 2 – Automated Sampling: Samples will be automatically extracted, conditioned, and analysed offline using VIS/NIR or hyperspectral cameras near the machine.

Secondary Textile Marketplace

To tackle textile waste and enable circularity, STREP is developing a digital secondary textile marketplace to facilitate the exchange of discarded textiles as valuable resources.

Current Challenge: ~12.6M tonnes of textile waste are generated annually in the EU, with low recycling rates due to siloed systems and lack of standardised data exchange.
STREP’s Marketplace Goals:
Automate and connect existing stakeholders’ workflows.
Enable dynamic, standardised sharing of material availability.
Launch to third parties in Year 3 with scaling via partners, events, and outreach.
Key Features:
Digital Trading Platform: For individuals and businesses to list, buy, and sell used textiles, starting with clothing and fabrics.
Incentivised Recycling: Introduces a recycling-for-textiles model where discarded materials gain monetary value.
Demand Connection: Links textile supply with buyers willing to pay (WTP), such as recyclers and processors.
Impact:
Encourages participation in textile recycling through financial incentives.
Establishes standards and transparency to build trust in the quality and usability of recycled textiles.
Acts as a digital catalyst for circularity across the textile value chain.

This marketplace aims to close the information gap and unlock the full potential of textile reuse and recycling at scale.

Life Cycle Assessment (LCA) and Sustainability in Textile Recycling

STREP will conduct detailed Life Cycle Assessments (LCA) and Life Cycle Costing (LCC) to evaluate the environmental and economic impacts of textile recycling, considering raw material composition, origin, production, and use phases.

Key Objectives:

Comprehensive LCA: Assess the entire product life cycle—from raw material extraction to the final recycled product.
Decision Support: Use results to guide supplier selection and recycling technology choices based on fibre origin and composition.
Alignment with Policy: Apply principles from the EU Waste Framework Directive, Circular Economy Action Plan, and EU Strategy for Sustainable and Circular Textiles.

Key Elements:

E-LCA & LCC: Measure environmental impact and costs across the full life cycle using standardised methods (ISO 14040/14044).
Chemical Safety: Monitor and manage hazardous substances (e.g. SVHCs under REACH).
Eco-Design: Apply 10 eco-design principles to minimise materials, pollution, and energy use.

Tools & Implementation:

Online LCA-LCC Tool: A web-based tool will:
Simplify data collection for pilots.
Provide visual breakdowns of impact by material/process.
Support eco-design comparisons to select optimal alternatives.
Circular Metrics:
Apply Product Environmental Footprint (PEF) and Environmental Product Declarations (EPD).
Integrate the Circular Footprint Formula (CFF) to quantify recycled content, recyclability, energy recovery, and disposal.

Integration:

Early-stage workshops to train partners and perform preliminary LCAs.
Use findings to optimise design decisions for textile products and robotic applications.
Feed LCA/CFF results into the Digital Product Passport (DPP) to support transparency and compliance.

Advancing End-of-Life (EOL) Textile Supply Chain Integration and Knowledge

STREP applies the CIMO logic (Context-Intervention-Mechanism-Outcome) to develop and evaluate innovative Supply Chain Management (SCM) solutions aimed at improving circular textile flows.

1. Context Analysis

STREP begins with analysing the current EOL fibre supply chains to identify:

Volumes, qualities, and seasonality of recyclable textiles.
Existing supply chain structures, actors, roles, and logistics capabilities.
Dominant material flows and business models.

This phase includes interviews, observations, and data synthesis to trace fibres from collection to recycling.

2. SCM Interventions & Evaluation

The project will assess proposed interventions from a SCM perspective, identifying:

Barriers and enablers under various supply-demand scenarios.
Pre-sorting impacts on material fractions and fibre availability.
Coordination methods between stakeholders and collection initiatives.
Alternative supply chain network designs aimed at lowering costs and environmental impact.

3. Innovative SCM Solutions

New models will focus on:

Improving coordination between supply chain actors.
Enhancing traceability via advanced data collection aligned with fibre characterization.
Designing systems that share decision responsibilities and information flows across the supply chain.
Evaluating logistic synchronisation in circular systems characterised by:
Supply-driven dynamics.
High volume variability.
Quality and demand uncertainty.

4. Granular Analysis of Recyclables

Unlike past studies that rely on manual pre-sorting or limited fibre categorisation, STREP will leverage its partners’ capabilities to analyse recyclables in more depth:

Fibre quality (via real-time fibre length measurement).
Colour and content combinations.
Simulation of multiple supply chain scenarios.