Title : Turning waste into water treatment media: Waste-derived aggregates in nature-based solutions for treating diverse water matrices
Abstract:
The transition towards a circular and climate-resilient water economy requires treatment systems that recover water while reducing dependence on virgin construction materials. This keynote explores the use of waste-derived aggregates as filtration, support and reactive media in nature-based solutions for the treatment of diverse water matrices. Particular attention will be given to aggregates produced from construction and demolition waste, water treatment sludge and waste-derived geopolymers. Their suitability for use in biofilters, vegetated channels, constructed wetlands and related systems depends on their physical, hydraulic, mechanical, mineralogical and chemical properties, including particle-size distribution, porosity, permeability, structural stability, alkalinity, surface area, sorption capacity and compatibility with plants and microbial biofilms.
The presentation will examine their application to polluted surface water, groundwater, domestic wastewater, greywater, landfill leachate, industrial and agricultural wastewater, rainwater and urban stormwater. Within these systems, contaminant attenuation may occur through filtration, sedimentation, adsorption, ion exchange, precipitation, biodegradation, nitrification–denitrification, plant uptake and pathogen inactivation. These combined processes can contribute to the removal of organic matter, nitrogen, phosphorus, emerging contaminants and pathogenic microorganisms. Drawing on current research and practical examples, the keynote will also discuss the main barriers to implementation, including material heterogeneity, clogging, excessive alkalinity, release of salts or trace elements, long-term hydraulic performance, environmental safety and end-of-life management.
The lecture will demonstrate how appropriately processed and characterised waste-derived aggregates can connect waste valorisation, water treatment and nature-based infrastructure, offering a scalable pathway towards low-energy treatment, water reuse and more resource-efficient urban and rural systems.
