Organic waste streams in the wine industry

Sammanfattning: Today, the annual global production of grapes surpasses seventy million tonnes. Of the grapes used toward winemaking, one fourth end up as pomace. In addition to pomace, vine pruning residues, stems and wastewater sludge contribute to the immense volumes of waste that for a long time has been considered as without value. The aim with this literature study is to provide a deeper knowledge about the extent of waste from the wine industry. In addition, to investigate current and previous methods of by-product management, and evaluate the benefits and drawbacks of applying them. An additional aim is to present and evaluate more innovative uses that can be applied to utilize the full potential of the plant residues more efficiently. This is done to determine if innovative methods can add value to the industry while reducing the environmental impact. The previous, current, and potential future applications on wineries of different sizes is also evaluated. This is made to determine if the methods will be predominantly beneficial or detrimental to the production value. Most common previous and current methods are incineration and landfills, both with harmful effect on the environment. Other current day methods of by-product management are the production of grappa, using grape pomace as feed and composting. The production of grappa and similar spirits hold great cultural and economic value to the producing countries, but the volume of pomace is only slightly reduced. Grape pomace as feed have been studied with various outcomes. Composting grape pomace is, despite the benefits, not as common as it should be. Few data are available on the proportion of wineries which compost their own residues, however, as an example, in the San Juan province in Argentina, only 5% of wineries compost their by-products. New innovations for the utilization of plant residues include using grape pomace in construction and as an adsorbent of heavy metals. Bioactive compounds can also be retrieved from grape pomace, to be used as food additives or nutraceuticals. Antioxidants show great promise for counteracting coronary heart disease and in preventing lipid oxidation in meats. The production of biofuels presents an option to fully exploit the potential of the plant residues. Producing fuels to reduce demand for externally sourced energy is found to benefit even vineyards with production below 50 tonnes.