Historically, cleaning practices in the wine industry have involved the use of hypochlorite, sodium hydroxide, tri-sodium phosphate, and in some cases a final rinse with citric acid. While the use of hypochlorite and citric were phased out many years ago, the continued use of strong caustic soda and tri-sodium phosphate solutions results in a significant sodium footprint in treated wastewater. The design and operation of aerobic wastewater ponds in wineries has generally focused on the biological oxygen demand (or BOD) of the winery wastewater whether from grape pulp, yeast and wine residues or discharged cleaning solutions. The energy and land requirements of this treatment approach and the carbon, nitrogen, phosphorus and sodium footprints of these practices are now no longer sustainable. A green chemistry alternative is the use of dilute, inorganic potassium-based buffers (KOH and KHSO4) and hydrogen peroxide, employed at ambient temperatures as an alternative sanitizing protocol. Such an approach results in no contribution to the BOD and chemical oxygen demand (or COD) measures and insignificant contributions to the sodium, carbon, nitrogen and phosphorus footprints in the discharged waters. The move towards the use of dilute solutions of monovalent inorganic buffers also permits the application of nanofilter membranes for solution and buffer recovery, with the potential to significantly reduce the total chemical footprint of winemaking cleaning practices.

Paired potassium-based buffers for sanitizing winery equipment and the carbon, nitrogen, sodium, and phosphorus footprints of winery cleaning practices

248th National Meeting (2014)

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