(Fig. 1b). At the inlet, a storing cistern was constructed with a serrated
overflow weir on one side, which facilitated a horizontal flow
of the water (Fig. 2). In the bottom of the CWs near the outlet, a
system of perforated 160-mm (in diameter) PVC pipes was placed
to ensure efficient drainage. The wetland was planted with a mixture
of Canna indica, Iris tectorum, Acorus calamus, Cyperus papyrus
and Thalia dealbata, which propagated rapidly and soon covered
the entire surface of the CWs within a single growing season (see
Table 1 for details on the plants used). These perennial aquatic or
marsh plants have extended root systems and large biomass and
were easily obtained in this district. After the construction and
planting, the systems were allowed to acclimatise for 2 months to
let the plants and microorganisms develop. During this period, the
CWs were loaded with water from the fishpond at loading rates that
varied between 300 (153 m3/day) and 600 (306 m3/day) mm/day.