The Alexandra system will be designed as a network of local grey-water disposal points that will be connected to multiple subsurface flow constructed wetlands throughout the study area. The wetlands are designed as filters with wetland plants, and the treated water will drain to either existing storm-water ditches or sewers. The participatory design and construction part of the project will be supported by pilot-scale studies in greenhouse wetlands, focusing on how the microbial communities in the wetlands impact the treatment efficiency regarding both chemical variables and some selected pathogenic organisms. Different locally available filter materials will be tested with respect to hydraulic and chemical properties in column experiments before being used in the full scale system.
In the full scale systems, interviews, workshops and surveys will help inform the team on how the systems are used and how different actors in the area perceive and interact with the wetlands. On-site chemical and microbial samples will also help determine how well the systems are providing the indented water quality outcomes. Combining on-site social and natural sciences as well as greenhouse and lab methods is crucial to ensure sure that the treatment system is effective in the long term.