The Weight of Environment Aspect in the Choice of Vinasse Processing with New Technology through Economic Assessment

Abstract

Vinasse improper disposal can cause damages to the environment. Fertigation, concentration and digestion aerobic or anaerobic generating fuel gas are the main technologies for vinasse use. Such alternatives present different impact on the environment; however, the weight of environment aspect in the decision remains under discussion. In this paper, authors present a discussion and valuations of environmental aspects about the main technologies of vinasse treatments. First, authors elaborated questionnaires, consulting specialists about the environmental and economical aspect of decision for changing to more environmentally friend technologies. The answers strongly suggest that the decisions of companies are mainly motivates by economics issue, and changing the current technology would be possible only if IRR (Internal Rate of Return) remains around 25%-30%. Then, authors proposed and performed calculations for inserting environmental aspects in the economical evaluation of technologies. The environmental resources performed considering carbon credit, economy with mineral fertilizers and the cost avoided with environmental fines. Scenarios and sensitivity cases performed, presenting discussions about the weight of environmental aspect in technology choice. It is possible to propose government policies that can economically value environmental benefits, such as tax reductions for people using vehicles to RGN (Renewable Gas Natural) or the implementation of a green label for companies that use biogas or RGN in their production processes (green label can be a differential or an extra score for company in future public bids, for example). The results showed that environmental aspect impacts directly the NPV (Net Present Value) of each technology, which can lead even to positive financial returns to companies; however, depending on valuation of environmental resources. Considering the environmental feature in economic impacts, the best option is the use of anaerobic digestion to produce energy that reduces carbon dioxide emissions or anaerobic digestion to produce gas if considering environmental scenario with the government policy of exemption from the tax on the ownership of motor vehicles. From the point of view of the land and water, it is possible to value economically in qualitative aspects through sectoral governmental policies.