Particle and bulk media characteristics of food waste compost-based biomedia by dynamic high-temperature aerobic composting process

Abstract

The dynamic high-temperature aerobic composting (DHAC) process, as a decentralized system, is considered a sustainable strategy for renewable resource-based raw materials. The food waste compost-based biomedia (BMFWCs) produced within five days of the DHAC process exhibited the physical properties of peaty topsoil with acceptable maturity under the meso-thermophilic phase. To understand the particle and bulk media characteristics of the BMFWCs, organic matter (OM) fraction–density–porosity parameters, particle size distribution, and uniformity coefficient were considered. Operating the DHAC process produced end products characteristics of relatively high total porosity (φb,T) and low dry bulk density (ρb) compared to the conservative mixture theory due to binary mixing and shape effects. A significant change in total porosity was estimated as an increase in non-spherical fibrous particles within the OM fraction of 0.4. Appropriate organic–mineral additives led to the effective arrangement of the variable porosity structure and improvement of aggregate stability (fom,spent coffee grounds≥0.2, fm,oyster shell powder≤0.4). The Forced aeration supply contributed to the expansion of the open space and macropore structures that serve as gas passages in the BMFWCs, while the introduction of microbes (Bacillus subtilis) promoted the biodegradation of medium and small macroaggregates (0.25–2 mm). The BMFWCs produced by the DHAC process was expected to have application potential in sustainable nature-based solution technology, due to appropriate particle properties, uniformity, and maturity.