Constructed wetlands using Cyperus alternifolius plants are effective in treating household greywater. A study compared an old and a new wetland system and found both had high removal efficiencies for pollutants like BOD, TSS, and detergent. The old system performed just as well as the new one, showing that it is still effective after four years. The treated water met national standards for discharge and irrigation, indicating that constructed wetlands are a sustainable solution for household greywater treatment.