Assessment of Water Reclamation and Reuse Potential in Bali Province, Indonesia

Abstract

Bali Province, Indonesia, experiences serious water shortages and groundwater over-abstraction due to rapidly increasing water demand. Therefore, this study aimed to assess the potential for water reclamation and reuse in Bali Province, focusing on the operational performance of two wastewater treatment plants (WWTPs). Although the Suwung WWTP could increase its treatment capacity to produce reclaimed water for irrigation and landscape, there are multiple management issues to be addressed, including fluctuating water demand, limited customer base beyond hotels, concerns about water quality and safety, and cultural perceptions of reclaimed water. In addition, despite the organic loading rates being lower than the design value, the treatment performance of the Suwung WWTP was found to be significantly lower than that of the ITDC WWTP, which achieved high BOD, COD, and TSS removal rates by performing good maintenance of aerators and post-treatment based on dissolved air flotation (DAF). Causal loop analysis indicates that aerator malfunctioning causes multiple problems, such as low dissolved oxygen, poor BOD removal, sludge carryover, and low sludge concentrations. Therefore, regular maintenance of aerators, as well as the development of aerators robust against malfunctioning, are fundamental to producing effluents from stabilization ponds that meet the requirements for irrigation and landscape reuse.