Source-separating wastewater systems as an alternative to replacing the existing sewer network: a proposed conceptual framework.

Source-separating wastewater systems are a potential alternative for new urban development, particularly in areas where the use and/or replacement of existing sewer infrastructure is not feasible. However, their implementation faces challenges, with low cognitive legitimacy emerging as a key barrier. This study proposes a conceptual framework to strengthen the cognitive legitimacy of source-separating wastewater systems. Workshops were held to identify the main concerns about the implementation of source-separating wastewater systems. Results from workshops were used as inputs for the literature review, and with the aid of additional interviews, a preliminary framework was proposed. The main findings enabled the proposal of four alternatives of source-separating wastewater, along with the identification of main characteristics, potential consequences, and corresponding mitigation measures. Furthermore, the study presented a relationship between these four alternatives and relevant secondary drivers. These insights served as the foundation of the proposed conceptual framework. The suggested framework aims to support stakeholders proposing source-separating wastewater systems in new developments in the planning phase by analysing different configurations and identifying the considerations behind and consequences of their implementation.