Model of COD and PO

Water pollution remains a critical environmental issue in Indonesia, particularly exemplified by the algae bloom phenomenon in Bima Bay. As a potential solution, it is necessary to treat the water with phytoremediation, which involves the use of a combination of various aquatic plants. This study aims to evaluate the efficacy of Ipomoea aquatica, Pistia stratiotes, and Eichhornia crassipes, along with Effective Microorganism 4 (EM4) as a bioremediator, in reducing pollutants in Bima Bay. This study adopts a quasi-experimental pre-test-post-test control group design. Results show that the initial Chemical Oxygen Demand (COD) in the river water was 539.7 milligrams per liter (mg/L), while the phosphate (PO4) concentration was 0.16 mg/L. Phytoremediation using the Ipomoea aquatica (water spinach), Pistia stratiotes (water lettuce), and Eichhornia crassipes (water hyacinth) plants has demonstrated the effective reduction of river water COD level by 5.3 mg/L to 95.5 mg/L. However, the method proved ineffective in reducing river water PO4 level, with an increase of 0.03 mg/L to 0.32 mg/L. The Kruskal-Wallis test yielded statistically significant results, indicating notable differences in COD and PO4 levels in river water across various measurement periods within each treatment group. The findings indicate that phytoremediation using Ipomoea aquatica, Pistia stratiotes, and Eichhornia crassipes with EM4 as a bioremediator is an effective approach for reducing COD levels in river water. However, this method proved less effective in reducing PO4 levels, which may continue to pose challenges in addressing water pollution in Bima Bay.