title: Merging two waste streams, wood ash and biowaste, results in improved composting process and end products.
abstract: A trial was carried out to evaluate the influence of wood ash admixture on biowaste composting. The aim was to find the optimal dosage of ash addition to enhance the composting process without endangering the final compost characteristics and use. Six treatments including an unamended control (K0) and composts with additions of 3% (K3), 6% (K6), 9% (K9), 12% (K12) and 15% (K15) of wood ash (w/w) were studied. The composting process was monitored in situ for 49days, by measuring temperature, CO2, O2, and CH4 in the piles and pH, electric conductivity (EC), and inorganic N in the laboratory. At the end of the process, the products were tested for Reifegrad (maturity), toxicity and quality. The addition of up to 15% of wood ash to biowaste did not negatively affect the composting process, and the initial differences found between both the low and high ash-treated composts were attenuated with the ongoing process development. Nevertheless, and mainly due to Cd level, composts with higher ash amendment did not comply with the highest quality standards established by the Austrian Compost Ordinance. The failure of obtaining class A+ quality after ash amendment emphasizes the need for a rigid quality selection of (bottom) ashes and thus reducing environmental risks related to high pollutant loads originating from the ashes.
authors.affiliation: Universität Innsbruck, Institut für Mikrobiologie, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: marina.fernandez@uibk.ac.at.
authors.forename: M
authors.initials: M
authors.lastname: Fernández-Delgado Juárez
authors.affiliation: Universität Innsbruck, Institut für Mikrobiologie, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Gómez-Brandón
authors.affiliation: Universität Innsbruck, Institut für Mikrobiologie, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Insam
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D017744:Medical Waste Disposal / Q000379:methods; D012037:Refuse Disposal / Q000379:methods; D014934:Wood / Q000737:chemistry
chemical_list: D017744:Medical Waste Disposal; D002606:Charcoal
keywords: Compost maturity; Ecological risk; Gas emissions; Heavy metal content; Waste valorisation