From waste to resource: Training young researchers on developing innovative, circular solutions for waste sludge

Project Information

INCLUE

Grant agreement ID: 101120427

DOI

10.3030/101120427

EC signature date 14 July 2023

Start date 1 October 2023

End date 30 September 2027

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 2 701 720,80

Coordinated by

KATHOLIEKE UNIVERSITEIT LEUVEN
Belgium

Periodic Reporting for period 1 - INCLUE (From waste to resource: Training young researchers on developing innovative, circular solutions for waste sludge)

Reporting period: 2023-10-01 to 2025-09-30

Summary of the context and overall objectives of the project

The overarching aim of INCLUE is to provide top-level training to a new generation of high-potential doctoral candidates (DCs) in a crucial field of today’s society: the exploitation of organic waste streams as a resource.
In this training through research program, INCLUE doctoral candidates will focus on sustainable and circular solutions to treat wastewater treatment sludge containing a wide variety of (in)organic pollutants, enabling the application of this untapped resource for renewable chemicals, materials, fuels and fertilisers.
INCLUE hereby responds to the European Green Deal and Farm-to-Fork strategy, in which sludge has been identified as a prime biogenic renewable resource to boost circular economy in terms of renewable energy generation and organic fertilisers production.
INCLUE entails an intersectoral consortium of 6 academic and 11 non-academic partners from 7 countries, who have developed an interdisciplinary training program, encompassing the fields of chemical & environmental engineering, (nano)materials science, chemistry, environmental biotechnology, microbial ecology, life sciences, modelling and
ecotoxicology.
The success of the program is guaranteed via a unique combination of state-of-the-art PhD research, intersectoral secondments, international mobility and interdisciplinary platform-wide courses.

The Research objectives are:
• To develop and optimise sustainable techniques to enhance the properties and composition of sludge through removal of (in)organic pollutants to eliminate any adverse effects for sludge application (i) in a subsequent bioconversion process or (ii) directly as a fertiliser on land.
• To develop augmented fermentative bioconversion processes to produce renewable chemicals and fuels, and to recover nutrients from municipal and industrial sludges, potentially combined with pre-treatment technologies.
• To create tools to assess the overall environmental performance of treated sludges towards toxicity, pollutant soil dynamics and agricultural fertilising value in a combined decision support tool (WP3) for 5 different types of pollutants: pesticides, endocrine disrupting compounds, heavy metals, PFAS and antibiotics. Develop a socio-economic evaluation tool, to support decision-making and societal acceptance.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

WP1:
• First experimental campaigns completed for all pre-treatment technologies: ultrasound, microwave-assisted HTC, electrochemical treatment, and thermal/torrefaction processes.
• Optimal operating conditions for pollutant removal
• Analytical workflows for micropollutant detection in sludge refined, especially methods for PFAS in complex matrices.
• Initial results show promising removal efficiencies for PFAS, pharmaceuticals, heavy metals, pesticides and microplastics.
• Common challenges identified: matrix complexity, analytical limitations, and need to address potential formation of toxic by-products.
• All DCs completed first round of experiments and defined plans for next phase.
Main achievements:
• Validation of feasibility of four non-chemical, energy-driven pre-treatment concepts.
• First proof of concept results for pollutant degradation and removal in realistic sludge matrices.
• Harmonised experimental protocols and analytical workflows across partners.

WP2:
• Anaerobic fermentation studies performed using the pesticide Diuron; adaptation of microbial communities monitored over time.
• Inhibition trials, VFA/methane productivity and stress response analysed; metagenomic characterisation planned next.
• Assessment of biodegradable plastic bags under AD conditions completed at mesophilic and thermophilic temperatures; digestate quality and biogas yield studied.
• First production and characterisation of sludge-derived biochar achieved and batch digestion assays started.
• DCs engaged in courses, conferences, and collaboration activities.
Main achievements:
• Initial demonstration that sludge-associated pollutants (pesticides, plastics) can be addressed without compromising bioconversion performance.
• Insights into microbial behaviour, inhibition, and adaptation dynamics under realistic sludge conditions.
• First step towards engineered microbial consortia and optimised reactor operations.

WP3:
• Foundational work started for ecotoxicity, environmental impact assessment and modelling of treatment scenarios.
• First results for biosensor concept using Indicator Displacement Assays for multipollutant detection and toxicity screening.
• Limitations in real sludge matrices identified and strategies for improving selectivity defined.
• Embryotoxicity, endocrine disruption and toxicity assays applied across a full-scale WWTP; persistence of endocrine-active compounds observed in sludge streams.
• Database creation and sample characterisation underway for sludge and sludge-derived products (physicochemical properties, pollutants, toxicity, nutrient value).
• LCA models for AD and THP developed and compared; environmental hotspots and advantages mapped.
• First version of multi-criteria decision-making framework drafted.
Main achievements:
• Strong methodological foundation for a combined environmental-techno-economic decision support tool.
• Multi-layer data integration platform established: analytical, toxicological, agricultural and socio-economic dimensions.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Across the three scientific work packages, the project already demonstrates several advances towards exceeding current scientific and technological practice:.

In Work Package 1:
• Application of multiple non-chemical, energy-driven pre-treatment techniques (ultrasound, MW-HTC, thermal, electrochemical) specifically tailored for multi-pollutant removal in sludge is still largely unexplored at this level of integration.
• Development of improved analytical methods for PFAS, heavy metals and microplastics in complex sludge matrices contributes to enhanced detection capability where standard methods are insufficient.
• Initial indication that treatment conditions can be tuned to affect pollutant fate and transformation rather than merely extract or dilute them.

In Work Package 2:
• Novel coupling of sludge pre-treatments with targeted bioconversion strategies for simultaneous pollutant removal and resource recovery.
• Generation of new knowledge on microbial adaptation and community responses to pesticides and biodegradable plastics under anaerobic conditions — areas where available research is still fragmented.
• Systematic assessment of bioplastics degradation in AD and impact on digestate quality is a relevant advancement for real-world deployment of organic waste systems.

In Work Package 3:
• Introduction of biosensor-based toxicity indicators for sludge matrices (IDAs) and integration with endocrine-disruption assays creates a new framework for ecotoxicity and regulatory compliance monitoring.
• Implementation of a multi-database and multi-method evaluation (embryotoxicity, biosensing, phytotoxicity, LCA, LCC, MCDM) surpasses conventional single-indicator sludge evaluation approaches.
• Development of an integrated decision-support methodology that explicitly combines technical, environmental, economic and policy criteria is a clear step beyond current decision-making practice for sludge valorisation.