Potable Reuse of Coalbed Methane-Produced Waters in Developing Country Contexts—Could the Benefits Outweigh the Costs to Facilitate Coal Transitions?

Development of coalbed methane (CBM) projects is critical to the achievement of climate change goals because it will help facilitate coal-to-gas transitions in Asia-Pacific countries with low conventional gas reserves. However, growth in CBM in these regions will necessitate strategic, sustainable approaches to produced water management. We posit that it may be possible to deliver synergistic water, energy, and health benefits by reusing CBM-produced waters as potable water supply in water-stressed coal-bearing regions. The goal of this study is to probabilistically evaluate life cycle costs and benefits of using reverse osmosis to treat CBM-produced water in the Damodar Valley coalfields in eastern India. Two treatment configurations are assessed, namely, centralized, and decentralized (i.e., in-home). We find that both configurations offer good cost-effectiveness based on two separately computed metrics to account for the value of health improvement benefits (i.e., disability-adjusted life years (DALYs) averted or monetized health benefits). We also observe that centralized systems are more cost-effective than decentralized, because they reduce capital cost and use-phase energy consumption per unit-volume treated. Average estimated values for the cost–benefit ratio are <0.5 and 1.0 for centralized and decentralized, respectively. Normalizing by anticipated health benefits, cost-effectiveness metrics are <$30/DALY for the centralized system versus <$200/DALY for the decentralized system. These results are highly sensitive to the value of statistical life and baseline water access. A related analysis taking into account both CBM-produced waters and mine waters revealed that deployment of reverse osmosis (RO) could provide drinking to approximately 3.5 million people over 20 years in the Damodar Valley region. These results have interesting implications not only for the study region but also for other CBM-producing countries experiencing chronic severe water stress. [ABSTRACT FROM AUTHOR]