Assessment of carbon footprint of potable water production: A case from Bangladesh

Carbon footprint (CF), a measure of greenhouse gas (GHG) emissions, is currently a global concern because of its significant effects on climate change. Understanding GHG emissions from potable water production is important because water treatment and distribution consume much energy while emitting a significant amount of GHG. With economic and population growth, water demand has increased, resulting in higher GHG emissions. This study aims to assess the CF of potable water production in Bangladesh, focusing on the country’s economic capital, Chattogram. This study estimates and compares the CF of the treatment, distribution, and consumption phases. It also estimates the CF of different water treatment plants (WTPs) during the treatment phase. WTPs use electricity for a full-scale operation, during which approximately 4.5 million m³ of raw water of varying turbidity is treated. This study calculates a country-specific GHG emission factor for Bangladesh’s electricity generation method as different sources produce different quantities of GHGs. This study also considers the energy consumed to distribute water from the WTPs to household rooftop tanks in the distribution phase. For the consumption phase, the study considers the energy consumption for domestic water treatment, which involves boiling of a portion of treated water for drinking purposes. The study estimates that approximately 0.18, 0.27, and 17.52 kg CO₂ equivalent (CO₂-eq) are emitted in the treatment, distribution, and consumption phases, respectively, for the production of 1 m³ of water. Boiling at the consumption phase alone generates 97.48% of the total CF. The daily CFs for surface water and groundwater use in 2017 were 16,387.78 and 34,092.08 kg CO₂-eq, respectively; those in 2022 were 83,769.25 and 2130.97 kg CO₂-eq, respectively. The outcome of this study will assist stakeholders and policymakers in the progress of SDG-13 and in effective planning and operational decision making for sustainable water systems.