Advantages and drawbacks of OFMSW and winery waste co-composting at pilot scale

The winemaking industry produces large volumes of waste which can be recycled and valorized. This study evaluates the advantages and drawbacks of valorizing skins, seeds and stalks from the processing of grapes for the production of Pedro Ximenez wine through co-composting with the organic fraction of municipal solid waste (OFMSW). The ratio of a mixture of both wastes was evaluated. According to the evaluation of the aerobic biodegradability of OFMSW and winery waste (WW) independently, a mixture ratio of 50:50% w/w was determined to be the best option. A slight decrease in the biodegradability of the OFMSW-WW mixture (40%) with respect to the biodegradability of OFMSW was found. Although the biodegradability of OFMSW-WW was lower than that of OFMSW, the co-composting of WW with OFMSW presented numerous advantages: the physico-chemical variables of WW were improved, the heavy metal content of the mixture was adequate during the composting process and corresponded to a compost type A with the exception of the Cd content. Furthermore, the odor emissions produced during the co-composting process were lower than those produced by OFMSW composting carried out under similar conditions. Consequently, co-composting might be a suitable alternative for recycling and valorizing winery waste, with the consequent environmental benefits.