Material and energy flow analysis of the Malawian tea industry

This paper briefly reviews the material and energy flows of the Malawian tea industry, in order to identify opportunities and reduce its environmental impacts. The review also details the concept and methodology as well as studies on applications of material and energy flow analysis. Environmental impacts are calculated with a life cycle assessment approach, using CML methodology. Results indicate that green leaf consumption in the studied factories ranged from 4.19 to 6.33 kg green leaf/kg made tea (MT), with an average of 4.96 kg per kg of made tea compared to 4.5 and 4.66 kg green leaf for tea factories in Kenya and Sri Lanka, respectively. Average wood consumption in Malawian tea factories is 3.35 kg/kg made tea and specific water consumption ranged from 1.92 to 8.32 kg/kg MT. In addition, the average value of greenhouse gas (GHG) emissions for eight factories is 4.32 kg of CO2-eq/kg MT as compared to 2.27 and 2.7 kg CO2-eq/kg in similar factories in Kenya and Sri Lanka, respectively. The major sources emitting GHG are from boiler fuel combustion and stand-by diesel power generation system. The study indicates that global warming has the highest environmental impact (88%), followed by acidification (6%) and eutrophication (2%), whereas human toxicity is lowest (<1%). The findings demonstrate how MEFA provides early recognition of environmental problems and how it can be used to establish priorities for improving operations in the existing factories. (C) 2015 Elsevier Ltd. All rights reserved.