Constructed wetlands as a way to treat greywater in South African informal settlements  

The URBWAT project (entitled Designing, implementing, monitoring and understanding a grey-water drainage and partial treatment system within an urban informal settlement) is a collaboration between Swedish, South African, and German partners funded through the 2017 Water JPI funding call.

This 3-year project aims to improve access to water and sanitation for all by working in close cooperation with inhabitants of informal settlements to implement innovative grey-water reticulation and treatment systems. This entails moving beyond the design and construction of wetlands to treat grey-water, and iteratively evaluate what works and what does not in order to improve water quality for residents. New implementation work will focus on the township of Alexandra located in Johannesburg, South Africa, while the team will also work with an informal settlement in the Western Cape area (Langrug township in Stellenbosch) that has an established wetland system to continue evaluation and compare the process in both locations.

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.

Research team
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