Environmental and technical improvement of a grape must concentration system via a life cycle approach

Abstract

Irregularities in grape yields can often affect wine production both quantitatively and qualitatively. Hence concentration systems, such as those based on reverse osmosis, are often employed to overcome such problems. The present study illustrates the results of a life cycle assessment approach implemented as means to improve the existing performance and sustainability of a specific industrial reverse osmosis concentration system used in a southern Italian winery to concentrate a specific must. The application of lifecycle approaches to reverse osmosis must concentration is sparsely documented in scientific literature with little or no specific data. The life cycle assessment of this study, developed using large amounts of inventory data and other novel information gathered from industrial testing, has highlighted the use phase as the most impacting one due to the energy consumption during the concentration operations and due to the membrane cleaning operations. In view of these results, the machine setup was improved and tested by varying the feed-flow velocity and the resulting new setup re-assessed via a life cycle approach. The final results exhibit the relationship between permeate production and feed flow velocity that does not appear to have been sufficiently investigated in other work found in literature regarding wine must. Specifically, the curve fitted to the experimental readings indicates that the maximum performance of the reverse osmosis system under analysis is achieved with a feed-flow velocity of approximately 2 m/s. Furthermore the new optimised setup of the machine lowered the environmental profile of all impact categories within a range from a minimum of 25.3% to a maximum of 26.7%, due to lower energy consumption, higher permeate production and reduced cleaning operations for the membranes. Concurrently to the environmental optimisation a technical improvement was identified, namely the substitution of the over-dimensioned piston pump, together with a potential reduction of purchase, running and labour costs of the optimised reverse osmosis system. Overall the study highlights the utility of analysing industrial machinery, such as reverse osmosis must concentration systems, from a life cycle analysis perspective, that can bring about not only environmental sustainability improvements but also technical and economic developments.