Life cycle inventory and mass-balance of municipal food waste management systems: Decision support methods beyond the waste hierarchy Joel Edwards a,⇑ , Maazuza Othman a , Enda Crossin b , Stewart Burn a,c a Department of Chemical and Environmental Engineering, RMIT University, Melbourne 3000, Australia b Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn 3121, Australia c Manufacturing Flagship, Commonwealth Scientiﬁc and Industrial Research Organisation (CSIRO), Clayton 3168, Australia article info Article history: Received 22 November 2016 Revised 30 May 2017 Accepted 5 August 2017 Available online xxxx Keywords: Food waste Bioenergy Circular economy Life cycle Municipal solid waste OFMSW abstract When assessing the environmental and human health impact of a municipal food waste (FW) manage- ment system waste managers typically rely on the principles of the waste hierarchy; using metrics such as the mass or rate of waste that is ‘prepared for recycling,’ ‘recovered for energy,’ or ‘sent to landﬁll.’ These metrics measure the collection and sorting efﬁciency of a waste system but are incapable of deter- mining the efﬁciency of a system to turn waste into a valuable resource. In this study a life cycle approach was employed using a system boundary that includes the entire waste service provision from collection to safe end-use or disposal. A life cycle inventory of seven waste management systems was calculated, including the ﬁrst service wide inventory of FW management through kitchen in-sink disposal (food waste disposer). Results describe the mass, energy and water balance of each system along with key emissions proﬁle. It was demonstrated that the energy balance can differ signiﬁcantly from its’ energy generation, exempliﬁed by mechanical biological treatment, which was the best system for generating energy from waste but only 5 th best for net-energy generation. Furthermore, the energy balance of kitchen in-sink disposal was shown to be reduced because 31% of volatile solids were lost in pre- treatment. The study also conﬁrmed that higher FW landﬁll diversion rates were critical for reducing many harmful emissions to air and water. Although, mass-balance analysis showed that the alternative end-use of the FW material may still contain high impact pollutants. Crown Copyright Ó 2017 Published by Elsevier Ltd. All rights reserved. 1. Introduction Municipal solid waste is known to make a signiﬁcant contribu- tion to many of the world’s most critical environmental problems; including climate change, resource depletion and ecosystem dam- age. FW is typically the largest component of municipal solid waste in both developed and developing nations and, despite its biodegradable nature, is one of the biggest sources of pollution to water and the atmosphere stemming from solid waste manage- ment, particularly when landﬁlled (Laurent et al., 2014). Waste managers and policy makers the world over recognise the need to better manage FW. Many nations have thus implemented a number of legislative and policy tools in order to promote better management of FW from as early as 1997 (European Council, 2008; Kim et al., 2011; Kjaer, 2013; Zhang et al., 2014). Australia has recently implemented policy measures including landﬁll levies and incentivising source separation of FW (Edwards et al., 2015; Pickin, 2015; Randell et al., 2014). Yet, only 270,000 Mg of FW was sent for recycling in Australian for the ﬁscal year 2010/11, approximately 11% of municipal FW generated, with the remaining 2,720,000 Mg sent to landﬁll (Randell et al., 2014). Given this con- text and further increases to landﬁll levies, waste managers are seeking alternative methods of treating FW that both divert FW from landﬁll and achieve better environmental outcomes. When assessing the environmental impact of a waste manage- ment system (WMS), in Australia, and in many other nations, the assessment is guided by the waste management and treatment hierarchy, which is written into legislation (Randell et al., 2014). The hierarchy detailed as highest to lowest in priority is as follows (1) avoidance and the reduction of waste generation, (2) the re-use of waste i.e. cleaning and re-ﬁlling glass beverage containers, (3) the recycling of waste into alternative products, (4) the recovery of energy from waste, (5) treatment and disposal. Governments at all levels are henceforth interested in reducing waste as per http://dx.doi.org/10.1016/j.wasman.2017.08.011 0956-053X/Crown Copyright Ó 2017 Published by Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: RMIT University, Building 10, Level 12 Swanston St., Melbourne 3000, Australia. E-mail address: s3137258@student.rmit.edu.au (J. Edwards). Waste Management xxx (2017) xxx–xxx Contents lists available at ScienceDirect Waste Management journal homepage: www.elsevier.com/locate/wasman Please cite this article in press as: Edwards, J., et al. Life cycle inventory and mass-balance of municipal food waste management systems: Decision support methods beyond the waste hierarchy. Waste Management (2017), http://dx.doi.org/10.1016/j.wasman.2017.08.011