Constructed wetlands were tested to see how well they clean sewage at different flow rates. The researchers built three wetland cells, two with plants and one without. They tested the water going in and coming out for various pollutants. The results showed that the flow rate affected how well the wetlands cleaned up pollutants like organic matter and nutrients. The plants helped remove nitrogen, especially at longer flow times. Overall, the treated water met Malaysia's standards for safe discharge into water bodies.