Development of a blueprint for water reuse in Cape Town; Inform the Adaptable Implementation Program; Identification at pre-feasibility level which reuse schemes could follow the New Water Programme ; Align with Bulk Water Optimisation Study

Agriculture faces increasing challenges due to the degradation of natural resources and a growing global food demand, both exacerbated by the impacts of climate change Consequently, water scarcity has become a primary concern of this sector One of the ways to ensure water availability is to optimize water management through water balance analysis at the irrigation district scale This type of analysis can identify water losses and evaluate the ratio between supplied volumes and water Needs

Cape Town currently disposes of 55 ML/d of untreated wastewater daily through its marine outfall sewers (CCT, 2018) without any provision for reuse Wastewater reuse is not feasible within the existing system However, an alternative system that uses chlorinated seawater for sanitation may be a viable alternative to increase coastal areas' water supply resilience In line with sustainable transition, it is essential to broadly understand the potential environmental impacts of a new water source before introducing it, given the additional energy, treatment and distribution requirements associated with dual water system

The European Regulation 2020/741 represents the first legislation at the European-wide level in the field of water reuse A key aspect is ensuring the hygienic quality of water One component to ensure safe water reuse (ie unrestricted irrigation (Class A)) is to validate the treatment performance of water reclamation plants regarding bacterial, parasitic, and viral pathogens via indicator organic To this end, the regulation defines log10 performance targets for selected target organic, which should be achieved in 90 % of validation trials However, the regulation lacks to define in detail how validation monitoring should be performed and which statistical methods should be applied for subsequent data evaluation.