Industrial waste from biomass boiler: Ash as a liming replacement for Eucalyptus planting in Brazil

Abstract

Upon insertion of biomass into a boiler, the material is incinerated, generating heat for the system. The combustion of biomass in the boiler produces ash, which is comprised of inorganic and mineral components that possess the potential for usage as a soil amendment. This study aimed to evaluate the efficacy of utilizing bottom ash from a Eucalyptus wood panels company, either partially or wholly replacing liming, for Eucalyptus planting. Chemical, physical and morphological characterizations of the ash and chemical characterization of the soil were carried out. An experiment was set up for the development of clonal Eucalyptus (3 ×2 m spacing), using different concentrations of ash and/or lime in the soil. The chemical characterization of ash was considered safe for use in agriculture, according to current legislation in Brazil (Normative Instruction SDA, n° 27). The diameter above ground and height of the seedlings were evaluated during twelve months in the field. In all treatments, elements such as copper and zinc presented concentrations within the limit parameters for soil, set by the government agency, CETESB. The findings indicate the feasibility of partially or fully replacing liming with ash, thereby promoting a more sustainable integration of circular economy into forest-based industries' energy generation processes.