As solid biofuels gain increasing importance, the issue of rational management of the ash obtained from biofuel combustion is becoming increasingly relevant. This relevance will only increase in the future, since it is predicted that the main biofuel raw material will not be wood, but agricultural biomass with a high ash content. Biomass ash contains valuable nutrients, such as potassium and phosphorus, and therefore, it could be used for fertilization in agriculture. The concentration of nutrients in the ash can be made more balanced by granulating it with organic waste. This work presents the results of the environmental impact of using multi-crop biomass ash for fertilization of spring barley using the life cycle assessment method. Five scenarios were analyzed: (1) mineral fertilizer (MF), (2) non-granulated ash (NA), (3) ash and cattle manure pellets (ACM), (4) ash and sewage sludge pellets (ASS), and (5) ash and sapropel pellets (ASP). The results of the study show that all scenarios using ash for fertilization have a lower environmental impact compared with the scenario using only mineral fertilizers (MFs). The lowest carbon footprint (583.94 CO2eq.) was determined for the ASP scenario. Normalization of the results showed that the ASS and ASP scenarios are the best from an environmental point of view, with the lowest environmental impact (24.90 and 24.60 Pt, respectively).
Petlickaitė et al. (Sat,) studied this question.