The initial design criteria were a capacity of 400m3 d−1 and
influent levels of BOD (Biochemical Oxygen Demand) at 100mgL−1
and TKN (Total Kjeldahl Nitrogen) at 10mgL−1. To respond to the
experienced water scarcity on the island the treated wastewater
should be re-useable as a secondary water resource. Given the
framing premise of land scarcity, vertical flow constructed wetlands
were quickly agreed on as a main component of the system
because of their high treatment capacity and relatively smaller
footprint (