Repurposing Fly Ash Derived from Biomass Combustion in Fluidized Bed Boilers in Large Energy Power Plants as a Mineral Soil Amendment

Abstract

This research involved studying the physico-chemical parameters of fly ash derived from the combustion of 100% biomass in bubbling and circulating fluidized bed boilers of two large energy plants in Poland. Chemical composition revealed that ash contains substantial amounts of CaO (12.86–26.5%); K2O (6.2–8.25%); MgO (2.97–4.06%); P2O5 (2–4.63%); S (1.6–1.83%); and micronutrients such as Mn, Zn, Cu, and Co. The ash from the bubbling fluidized bed (BFB) was richer in potassium, phosphorus, CaO, and micronutrients than the ash from the circulating fluidized bed (CFB) and contained cumulatively less contaminants. However, the BFB ash exceeded the threshold values of Cd to be considered as a liming amendment. Additionally, according to our European Community Bureau of Reference (BCR) study Pb and Cd were more mobile in the BFB than in the CFB ash. Except for a low nitrogen content, the ash met the minimum requirements for mineral fertilizers. Acute phytotoxicity revealed no inhibition of the germination and seed growth of Avena sativa L. and Lepidium sativum plants amended with biomass ash. Despite the fact that low nitrogen content excludes the use of biomass fly ash as a sole mineral fertilizer, it still possesses other favorable properties (a high content of CaO and macronutrients), which warrants further investigation into its potential utilization.

The Effect of Mineral-Based Mixtures Containing Coal Fly Ash and Sewage Sludge on Chlorophyll Fluorescence and Selected Morphological Parameters of Deciduous and Coniferous Trees

“…Samaras et al [56] demonstrated that ash and sewage sludge mixtures meet phytotoxicity and ecotoxicity standards when small amounts of fly ash are added to sewage sludge. However, in a study Jarosz-Krzemińska and Poluszyńska [58], biomass ash with desirable physicochemical properties added to soil exerted no toxic effects on seed germination or plant growth. In the current study, mixtures containing only CFA were most phytotoxic.…”

Organic Petrographical Features of Fly Ashes Originating from Coal and Coal-SRF Co-Combustion

“…Additionally, the obtained results show that the studied fly ashes do not meet the requirements for utilization in the cement industry, as the unburned organic residuals are elevated [5,7]. Nevertheless, other applications, in which high content of organic matter either in an un-combustible or partially carbonized form is favorable, can be further investigated, such as implementation as soil-improving agencies, e.g., [30,31], or even in the environmental sector [32,33]. Additionally, the obtained results show that the studied fly ashes do not meet the requirements for utilization in the cement industry, as the unburned organic residuals are elevated [5,7].…”

Properties of Animal-Origin Ash—A Valuable Material for Circular Economy

“…Such action may be beneficial to avoid further land degradation and promote land restoration hence these issues are important in terms of Sustainable Development Goals (SDGs) [25,26]. The studies of biomass ashes in terms of fertilizer usefulness and environmental safety were conducted mainly for plant-origin biomass [27,28], and only limited studies for animal-origin biomass can be found in the literature. The majority of these studies relate to poultry litter ashes from combustion and gasification processes, while cow manure ash has been less studied.…”