The removal of chemicals from water sources that are harmful to humans and the environment can contribute to improving water quality. Biological treatment methods, such as bioaugmentation are an environmentally sustainable approach for pollutant removal. The 4-nitrophenol is the most hazardous nitrophenol chemical pollutant. In this study, a laboratory investigation was conducted on a flask scale to evaluate the rhizoaugmentation of 4-nitrophenol-polluted water. This was achieved by employing Rhodococcus sp. strain PKR-1, which was reintroduced into the roots of Spirodela polyrhiza. The selected strains were inoculated into the root at the rate of 10⁴ to 10⁶ colony-forming units (CFU) per plant. At high levels exhibited stability across five consecutive two-day degradation cycles, and full elimination of 4-nitrophenol was accomplished within these five repeated cycles. Therefore, the introduction of degraders into the root systems of aquatic plants has proven to be a successful method for treating effluents or aquatic resources contaminated with 4-nitrophenol.