Use of biomass ash-based materials as soil fertilisers: Critical review of the existing regulatory framework

Abstract

Growing quantities of biomass ashes are currently produced worldwide due to the increasing consumption of biomass in energy applications. The disposal of biomass ash in landfills is costly and leads to the loss of valuable resources. Biomass ash has important macro-nutrient contents and relevant soil liming capacity, and can be recycled to soils, thus contributing to biomass-to-energy process integration and a sustainable energy production. Although the EU Thematic Strategy for Soil Protection has highlighted the importance of promoting soil amelioration through nutrient recycling and some Member States have already recognised biomass-ash value in a context of circular economy, recycling of this material at the EU level and the potential use of ash-based material in fertilisers is still not properly framed by the EU regulatory framework. Adequate regulation for biomass ash from the energy sector is recognised of most importance as a driving force towards implementation of correct management and valorisation of ash as a raw material.This review provides a discussion on biomass ash properties and related EU regulations, notably the Waste Framework Directive and the Fertilisers Regulation, which are relevant for implementing a strategy for valorisation of biomass ash for soil amelioration purposes. Steps needed to provide the biomass ash with an appropriate end-of-waste and/or by-product status were identified. Key product and process aspects to enable the inclusion of biomass ash in the list of materials that can be used as fertilisers or as ingredients of soil fertilisers in the scope of the revised Fertilisers Regulation were discussed. Quality and safety standards to be harmonised at the EU level, as well as necessary revisions of the risk assessment framework were also discussed here.