Supply chain analysis for cassava starch production: Cleaner production opportunities and benefits Prus Pingmuanglek a , Napat Jakrawatana a, * , Shabbir H. Gheewala b, c a School of Energy and Environment, University of Phayao, Phayao, Thailand b The Joint Graduate School of Energy and Environment, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand c Centre of Excellence on Energy Technology and Environment, PERDO, Bangkok, Thailand article info Article history: Received 6 April 2016 Received in revised form 23 March 2017 Accepted 16 June 2017 Available online 18 June 2017 Keywords: Cassava starch Material Flow Analysis Supply chain Biogas Cassava pulp abstract This research assesses resource efficiency and the loss through the processes of the cassava starch production supply chain in order to find opportunities to improve resource use efficiency, reduce loss and recover resources from waste. The case study was conducted at a cassava starch company in the north of Thailand. The starch supply chain includes cassava cultivation, cassava root transport and processing of cassava starch. In the base case, 25,000 tonne of freshwater was used to produce 1000 tonne of cassava starch. Water consumption in the extraction process accounted for over 60% of freshwater use in the supply chain. The extraction and separation processes were the main hotspots because they consumed a large amount of water and a large portion of cassava mass including cassava pulp was separated out at these stages. Over 81% of energy was used in the starch plant including hot air (53%) and electricity (28%). Diesel used for crop production and transport accounted for only 6% and 12% respectively. Drying process was the hotspot in terms of energy use; the process used heat accounting for over 68% of the total energy use in the supply chain. Fortunately, hot air produced from biogas covered 100% of the hot air requirement and electricity produced from biogas covered 86% of the electricity demand in the plant. The conventional system of cassava starch production was compared with an improved one incor- porating changes in practice of crop production, transport and starch production. In the improved sce- nario, in crop production, several nutrient management practices were applied along with fertilizer optimization. The starch plant was modified to enhance water recycling and reduce loss in order to reduce cassava root input. Starch loss reduction was achieved in the fiber and pulp separation processes where the largest starch loss occurred. The results showed that the scenario of improved technology and management could reduce consumption of all resources and emissions including cassava roots (4%), fertilizers (50%), water (30%), wastewater (40%) as well as energy (8%). All of the cassava pulp could be recovered to produce ethanol instead of using for feed with some ending up in the landfill in the base case. All wastewater could be reused for irrigation in the cassava farms instead of being evaporated. Moreover, recovering cassava pulp for ethanol production led to positive energy balance and net GHG benefit of 107 t CO 2 eq/y. Net GHG benefit from wastewater reuse for irrigation in the improve scenario was 3 t CO 2 eq. © 2017 Published by Elsevier Ltd. 1. Introduction Cassava is a versatile plant that can be used for food, feed and fuel; it is a very important economic crop for Thailand which is the top cassava product exporter in the world. In Thailand, over half of the cassava is used for starch production, about 44% is used for producing chips and pelleted cassava for animal feed and only 2% is available for ethanol production (OAE, 2013). The cassava value chain in Thailand is worth over 3.7 billion USD and when including related value-added industries, it can be worth 8.5 billion USD. The supply chain created jobs for 2.4 million people (NSTDA, 2009). The Alternative Energy Development Plan (AEDP 2015e2036) has set a target to increase ethanol production from cassava and hence cassava use is expected to outpace (FAO, 2010; DEDE, 2014; * Corresponding author. E-mail address: napat_j@hotmail.com (N. Jakrawatana). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro http://dx.doi.org/10.1016/j.jclepro.2017.06.148 0959-6526/© 2017 Published by Elsevier Ltd. Journal of Cleaner Production 162 (2017) 1075e1084