Economic Analysis of NbS for Wastewater Treatment Under Uncertainties

Nature-based solutions (NbS) for wastewater treatment are environmentally friendly and sustainable approaches that utilise natural processes to remove pollutants and improve the quality of wastewater. In most developing countries, NbS are underutilised due to the lack of community awareness, policy support, financing mechanisms, and various uncertainties. This chapter provides support for technological, environmental, social, and governance aspects of NbS project implementation by presenting an integrated economic analysis of NbS under investment uncertainties. First, the viability of the project is analysed by applying an economic valuation of the ecosystem services offered by NbS. Next, the project is evaluated using benefit–cost analysis (BCA) from financial and societal perspectives. Then, the BCA is extended by integrating decision flexibility and the uncertainties in NbS implementation. Lastly, the proposed economic analysis framework is tested using the case study of existing constructed wetlands, an NbS for domestic wastewater treatment in Bayawan City, Philippines.