Vol.:(0123456789) 1 3 Waste Biomass Valor DOI 10.1007/s12649-017-0047-2 ORIGINAL PAPER Co-composting of Green Waste Mixed with Unprocessed and Processed Food Waste: Influence on the Composting Process and Product Quality E. R. Oviedo-Ocaña 1  · I. Dominguez 1  · D. Komilis 2,3  · A. Sánchez 2   Received: 3 June 2017 / Accepted: 5 August 2017 © Springer Science+Business Media B.V. 2017 end-product from treatment C was 4.8–5.0, which indicates that the product can be suitable for agricultural use. Keywords Biowaste · Composting · Green waste · Fertility index · Food waste Introduction Green waste GW represents a significant fraction of munici- pal solid waste (MSW). For example, in the United States in 2013, GW represented 13.45% of MSW (34.7 million tons) [1], while in Taiwan, GW accounts for 22–30% of MSW [2]. Municipal green waste (GW) commonly consists of tree wood and bark, pruning from young trees and shrubs, dead and green leaves, grass clippings and soil, and originates from municipal parks, gardens, reserves and domestic dwell- ings [3, 4]. GW has increased dramatically with the rapid development of urban green spaces in several countries [5]. GW management is often difficult and expensive due to its low bulk density. The principal cost is due to collection and transportation to landfill or treatment facilities [6]. Composting is an alternative for GW management in cities. For example, in the United States, 36 states have reported a total of 3474 GW composting facilities [7]. Other authors reported GW management in composting facilities like Benito et al. [8] in Madrid and Lopez et al. [6] and Cáceres et al. [9] in Catalunya, Spain. Composting can constitute a suitable method for the recy- cling of GW, since the compost obtained is a useful organic amendment and/or organic substrate that can be reincorpo- rated into the economic system, can reduce waste to be dis- posed, and can reduce emissions of greenhouse gases [10]. In addition, compost can sequestrate carbon and result in reduced net CO 2 emissions to the atmosphere. However, the Abstract Green waste (GW) represents a large fraction of municipal solid waste (MSW) and has increased signifi- cantly with the rapid development of urban green areas in some countries. Composting is an appropriate method for the treatment and recovery of these wastes. However, the high content of lignocellulosic substances in GW is known to slow down the decomposition process. This research evaluated the effect of introducing processed food waste (PFW) and unprocessed food waste (UPFW) on compost- ing of GW, it monitored the process itself and assessed the end-product quality. A field-scale experiment was devel- oped using three treatments: Treatment A (100%GW), Treatment B (40%UPFW + 60%GW) and Treatment C (50%GW + 30%UPFW + 20%PFW). Treatment C reached thermophilic temperatures in a shorter time than the other treatments and maintained those temperatures for longer periods. In addition, treatment C reached ambient temper- atures during curing in a shorter time compared to treat- ments A and B. An improved product quality was observed in treatment C compared to other treatments. For example, products from treatment C had lower ash content, higher concentrations of TOC and P Total and lower EC values com- pared to treatments A and B. The final fertility index of the * D. Komilis Dimitrios.Komilis@uab.cat 1 Escuela de Ingeniería Civil, Facultad de Ingeniería Fisico-mecánica, Universidad Industrial de Santander, Carrera 27 Calle 9, Bucaramanga, Colombia 2 Composting Research Group, Department of Chemical Engineering, Universitat Autònoma de Barcelona, 08193 Barcelona, Bellaterra, Spain 3 Department of Environmental Engineering, Democritus University of Thrace, Xanthi, Greece