Strategizing Reclaimed Water Use in Metro Manila: A Hybrid Hierarchical DEMATEL–BWM Analysis of Adoption Barriers

Abstract

Amid growing water scarcity in Metro Manila, Philippines, the country is exploring the use of wastewater treatment plant effluents as an alternative potable water source through reclaimed water use (RWU). However, no prior study has systematically mapped the causal interrelationships among multidimensional RWU adoption barriers in the Philippine context. Classical DEMATEL applied directly to complex systems imposes a substantial cognitive burden on respondents. This study developed implementation strategies for RWU using a hybrid decision-making framework that integrates the Hierarchical Decision-Making Trial and Evaluation Laboratory (h-DEMATEL) and the Best–Worst Method (BWM). The hybridization process involved weighting the prominence and relation values from h-DEMATEL with the relative importance scores derived from BWM. Findings reveal that effective communication with stakeholders and the public is the most critical intervention, as it addresses key perceptual barriers, namely, lack of awareness and the disgust factor. Equally important is ensuring the integrity of RWU systems to mitigate public health concerns. In contrast, governance and behavioral barriers were identified as low-impact and weakly connected within the system, suggesting they should be addressed in later phases of implementation. The hybrid h-DEMATEL–BWM approach proves to be a valuable strategic tool for guiding RWU adoption in Metro Manila. Future research may validate these findings through broader population surveys and explore additional context-specific barriers to enhance decision-making and policy design.