This study focuses on the biological wastewater treatment for vegetable plots quality improvement. Based on planted wetland technology using vetiver grass, treated water quality was significantly improved at 95% performance. Toxic heavy metal and other pollutant loads were reduced. Chemical analyses revealed such improvement: pH, TOC, K, N, P, Cr VI, Cd, Pb were lowered. This simple, efficient and low-cost technology will be extended to two other sites in Matadi. Statistical analysis revealed significant differences between untreated and treated water pollutant loads.