Evaluating the efficiency of vetiver grass (Vetiveria zizanoides) for municipal wastewater treatment in Bahir Dar City, Ethiopia

Wastewater pollution is a pressing global environmental issue, which is intensified by urbanization and agricultural expansion. Rapid urbanization has resulted in increased municipal wastewater generation, necessitating the development of sustainable and effective treatment methods. The current study examines vetiver grass ( Vetiveria zizanioides ) as a phytoremediation method for municipal wastewater treatment, focusing on its ability to remove biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrogen (N), and phosphorus (P). Three vetiver plant densities (20, 40, and 60 plants/m 2 ) were evaluated to determine the optimal configuration for pollutant removal over a 9-week treatment period. The results demonstrated that a high-planting density vetiver (60 plants/m 2 ) achieved the highest overall removal efficiencies, reaching 89.7, 80.6, 60.5, and 40.8% for BOD, COD, nitrogen, and phosphate, respectively. These findings highlight the potential of high-planting density vetiver grass as a cost-effective and environmentally sustainable alternative for municipal wastewater treatment, providing valuable insights into planting density optimization under local Bahir Dar conditions and enabling scalable phytoremediation in resource-limited urban areas.