Technical, economic and environmental feasibility of the use of vinasse as an input for the production of organo-mineral fertilizer

Abstract

Vinasse is the main waste from the sugar and ethanol sector. Due its composition with high nutritional content, has as an alternative destination via fertigation practices. However, the distances and the high volumes to be transported can make this activity economically unfeasible, which, when carried out excessively, can cause undesirable environmental impacts. An effective strategy, still little explored, for the reuse of this residue is the production of organo-mineral fertilizer, an alternative closely linked to economic aspects in the production process since the expenses with commercial fertilizers can be reduced, as well as the high transportation costs associated with raw vinasse in fertigation. Moreover, the vinasse reuse would be maintained, however through controlled practices and lower environmental impacts. The present work evaluated the vinasse use as a precursor material in the production of organo mineral fertilizers, estimating the possible impacts on the soil by its use and presenting integrated systems for its obtainment. We summarized and critically discussed the past ten years (2011 – 2021, total number of papers revised: 175) of research data about vinasse composition, along with the limitations to be overcome in the near future to enable the obtainment of organo mineral fertilizers from vinasse. Three different setups were proposed for vinasse treatment with the combination of ultrafiltration (UF), nanofiltration (NF), two-stage anaerobic bioreactor (2S-AnMBR), and reverse osmosis (RO) processes. The systems were analyzed individually, and the composition of each stream was verified for its potential to be used in fertigation, as a granular and liquid organo-mineral fertilizer. The metals in vinasse composition not characterized the risk of soil contamination and the nutrients met the requirements for the formulation of organo-mineral fertilizer. The vinasse concentrate use, when applied via fertigation or organo-mineral fertilizer, provides savings of over 60% when compared to the fertilization process made only with commercial fertilizers, and the best efficiency of transportation was obtained with the granular organo-mineral fertilizer, proving that this form of the organo-mineral fertilizer is more economical for the scenarios studied. The processes demonstrated profit coming from the economy provided by the energy recovery and the lower environmental impacts in terms of CO2 and SO2 emissions. Complementary studies assessing the impact of phenolic compounds on the soil fauna are required to extend the use of organo mineral fertilizers.