Water-energy-nexus in water supply: a Case study on greenhouse gases emissions trends of a water utility company in Johor, Malaysia

Abstract

Carbon Footprint (CF) assessment of water utility company (WUC) was originally initiated in 2011. The WUC carried out a holistic assessment of the impact of WUC operations on the environment on activities ranging from water treatment, supply activities, administration and interaction with its stakeholders. The aim of this study is to determine the WUC's operational CF for the years 2012 - 2014 in units of kg CO2eq/m3 of raw water. The aim of this paper is threefold: (1) to examine the direct emissions of diesel usage for electricity generation, diesel and petrol usage for a fleet vehicle (2) to examine the indirect emissions from purchased electricity and (3) to investigate the indirect emissions of chemical usage at WTP. The carbon footprint measurement is carried out to identify the sources of Green House Gas (GHGs) emissions from the various WUC's operational and administrative activities. The Intergovernmental Panel on Climate Change (IPCC) standard was used to calculate the CF of WUC for the years 2012 - 2014 based on the identified sources of emissions. The results showed that the purchased electricity (85 - 90 %) has the highest overall carbon emission for three consecutive years (2012 to 2014). Second, petrol usage was the major contributor for staff commuting (3 - 4 %) and for transporting chemicals from producer to the WTP (6 - 7 %). The analysis showed that in 2014 the carbon footprint was similar to the situation in 2013. In 2014, the green gas emission increased to 207,295.73 Mt CO2eq due to the increase in WTPs numbers (that is from 27 to 42) with a capacity to treat 579,481,988.42 m3 of water. The outcomes of this study would serve as a guideline and benchmark for other water industries, especially in the Malaysia context.