Application of the analytic hierarchy process for the selection of recycling rainwater/household grey water to improve SIDS sustainability targets

Water and wastewater reuse and recycle are key prerequisite practices towards the achievement of sustainability commitments. However sustainable practices in small island developing states (SIDS) on the conservation and management of water resources have been shown to be woefully deficient in the absence of formal policies and systems to encourage the reuse and recycling of stormwater and greywater in households. The aim of this study is to investigate, and baseline, sustainable management practices in SIDS by examining the effects of urbanization, increased rainfall, inadequate infrastructure, and improper drainage on stormwater and greywater management. The analytical hierarchy process (AHP) and multi-criteria analysis (MCA) were employed to provide a systematic decision-making approach to analyze four critical criteria against five alternatives with the objective of evaluating the effectiveness of rainwater harvesting (RWH) and greywater reuse techniques within the context of Trinidad and Tobago. The findings revealed that the most critical criterion for reusing and recycling stormwater and greywater is awareness, while the top performing alternative was Rainwater Harvesting for Agriculture (RHA). The findings also showed a positive relationship between RHA prioritization with the priority score of awareness, lending credence to its feasibility and efficiency for sustainable water management practices in SIDS. The study discussed novel insights and contributed to the body of knowledge in promoting resilience and long-term sustainable development in the often ignored and underdeveloped regions of SIDS in three areas. Firstly, this study addresses the unique challenges faced by SIDS to ensure long-term water resource resilience by prioritizing investments in capacity building, policy support, infrastructure development, and fostering stakeholder collaboration. Secondly, the need to address challenges in legislative policy building and infrastructural development to ensure the successful implementation of these alternatives was justified. Finally, the study advocates continued research and innovation in this field by academia and professionals to inform new policies and improve contemporary practices to achieve both the sustainable development and management of water resources in SIDS.