Financial assessment of groundwater and rainwater treatments for school clean water supply

Abstract

The global primary school population has experienced a significant increase, in line with the pursuit of Sustainable Development Goal number 4 which strives to ensure inclusive, equitable, and high-quality education, fostering lifelong learning opportunities for all. However, not all schools, especially in developing countries, have access to a sufficient supply of clean water. For example, a 2021 World Bank study found that almost half (47%) of schools in Indonesia have no access to soap and flowing water, which is critical to disease prevention. In this study, we featured a case study of a school in Indonesia that mainly obtains its clean water supply from pumped underground water and treats it with reverse osmosis technology. This study analyzed the potential financial savings from adding combinations of a rainwater harvesting system, an adsorption–filtration system, an ultraviolet radiation disinfection system, and solar photovoltaics to the existing underground water pumping system in a case study school. We utilize local data encompassing factors such as rainfall intensity, facility investment, operation, and maintenance costs in the evaluation of financial performance for each scenario, employing methods such as net present value (NPV), benefit–cost ratio (BCR), and payback period. The findings indicate that the adoption of constructed scenario 1, incorporating an adsorption filtration system and UV disinfection, yields superior financial outcomes in this study. Scenario 1 results in 167,890 IDR NPV over its 12-year lifespan, 1.10 BCR, and a payback period as short as 2 months. The results from this study provide knowledge about the potential financial gains and technological alternatives for other schools in developing countries without access to a centralized clean water or energy supply.