Horizontal flow constructed wetland for greywater treatment and reuse: an experimental case

In the coming years, water stress is destined to worsen considering that the consumption of water is expected to increase significantly, and climate changes is expected to become more evident. Greywater (GW) has been study as an alternative water source in arid and semi-arid zones. Although there is no single optimal solution in order to treat GW, constructed wetlands proved to be effective. In this paper, the results of the treatment of a real GW by HFCW for more than four months are shown. In the preliminary laboratory-scale plant, Phragmites australis, Carex oshimensis and Cyperus papyrus were tested separately and showed very similar results. In the second phase, pilot-scale tests were conducted to confirm the performance in a larger scale and evaluate the influence of hydraulic retention time obtaining very high removal yields on turbidity (> 92 %), TSS (> 85 %), COD (> 89 %), and BOD5 (> 88%). Based on the results of the pilot-scale HFCW, a comparison with international recommendations by World Health Organization and European Union is discussed.