Sustainability Assessment of the Green Compost Production Chain from Agricultural Waste: A Case Study in Southern Italy

Horticultural farms are faced with the problem of disposing of huge amounts of agricultural by-products whose management requires sustainable solutions. Composting means to recycle organic waste to make compost-a high agronomic value product-able to positively affect soil quality: A good occasion to switch definitively from a conventional agriculture to an organic one. Nevertheless, composting can have negative direct/indirect environmental impacts. The aim of this research was to assess the sustainability of a windrow composting system, able to treat agricultural green waste of different typology ("light" and "heavy" with dry matter below or above 10%, respectively). Environmental impacts, energy consumptions, and production costs of all composting stages were evaluated by Life Cycle Assessment. Results show that the production of 1 ton of compost caused CO(2)eq emissions ranging from 199 to 250 kg and required between 1500 and 2000 MJ of energy; costs ranged between 98 and 162 euro, nevertheless lesser than the commercial green compost. The raw material typology affected significantly the composting process making compost based on "heavy" materials the most sustainable. These findings underline the need to spread this low technology process, easy to apply, especially in organic farms, and to promote the agronomic use of compost.