Agrochemical value of the liquid phase of wastes from fermenters during biogas production

Abstract

We tested the procedure of combined phytomass utilization Integrated Generation of Solid Fuel and Biogas from Biomass (IFBB) proposed for ensiled grass matter from the aspect of suitability of its use for a typical substrate of new Czech biogas stations, a mixture of cattle slurry, maize silage and grass haylage. The agrochemical value of the liquid phase from a biofermenter was also evaluated. We concluded that this procedure is suitable for the tested substrate and improves the agrochemical value of a fugate from biogas production. By chlorine transfer to the liquid phase, it enables to use the solid phase as a material for production of solid biofuels with a reduced threat of the generation of polychlorinated dioxins and dibenzofurans during combustion. However, the concentration of mineral nutrients in the liquid phase during IFBB procedure is extremely low after anaerobic digestion as a result of dilution with water, and so its volume value is negligible.