Fig. 1

a The SOPAS system utilised in the current study was connected to a RWH tank installed on a metal stand. A: Untreated RWH tank (capacity: 2 000 L), B: Inlet pipe leading into the SOPAS tank, C: High grade polyethylene tank (capacity: 125 L), D: 10 × High borosilicate glass collector tubes, E: Outlet pipe and water collection point. b The SODIS system with two polyethylene terephthalate (PET) bottles containing harvested rainwater. The SODIS system was constructed from a black polyethylene material that was lined with a reflective aluminium surface. The system was covered with a transparent Perspex lid to increase insulation