Bottled water or filtered tap water? A nexus-based sustainability assessment for Qatar

In Qatar, despite the presence of advanced water desalination infrastructure, heavy reliance on bottled water persists. This dependence contributes significantly to high energy consumption and plastic waste generation. A critical knowledge gap remains in evaluating the techno-economic and behavioral trade-offs between centralized bottled water systems and household-level filtration alternatives. The overarching objective of this study is to provide an evidence-based answer to whether drinking tap water treated with household filtration systems constitutes a more economically, environmentally, and socially sustainable option than reliance on bottled drinking water in Qatar. This study assesses a novel biomass-based, magnetic nanoparticle enhanced activated carbon (AC) filter developed at the Qatar Environment and Energy Research Institute (QEERI), part of Hamad Bin Khalifa University. The performance of this system is compared with conventional bottled water sources representing three dominant drinking water pathways: reclaimed groundwater, desalinated seawater, and treated sewage effluent. A multidimensional assessment framework is employed, integrating carbon auditing, Techno-Economic Analysis (TEA) through the estimation of the Levelized Cost of Water (LCOW), and flow-based game theory modeling to capture government policy influences and strategic interactions between policymakers and consumers. The results indicate that bottled desalinated water for human consumption imposes the highest economic burden, with LCOW values ranging from USD 0.15 to USD 0.22 per liter. In contrast, the innovative QEERI household filter achieves an LCOW at least two orders of magnitude lower, ranging from USD 0.00081 to USD 0.00102 per liter, while simultaneously reducing energy intensity. From a policy perspective, the game-theoretic analysis highlights the importance of targeted interventions, such as plastic levies or consumption subsidies to shift the Nash equilibrium toward more sustainable water consumption behaviors. The findings provide a practical blueprint for water-scarce regions to transition away from plastic-intensive bottled water systems toward low-cost, energy-efficient household filtration technologies.