Assessing the feasibility of using phytoremediation technologies: a case study of two wastewater treatment plants in Mpumalanga Province, South Africa

Optimising wastewater treatment to ensure compliance has become a growing focus for many regions.Recently, the application of passive treatment methods has gained traction, whereby it has been adopted either as a complete treatment system or as a complementary tool to polish treated wastewater effluents.This study aimed to assess the potential of phytoremediation methods for treating domestic sewage, bringing forth innovation and sustainability in failing municipal treatment plants, a case study of two WWTPs in Mpumalanga province, South Africa.Wastewater effluent quality was analysed from 2017 to 2022 to establish the effectiveness of the current treatment systems employed at both WWTPs.Despite conventional treatments, the data indicated that various parameters were not adequately removed, including suspended solids, phosphates, ammonia, nitrates, and faecal coliforms.By applying a Weighted Arithmetic Wastewater Quality Index, it was found that the discharged effluents were unsuitable for the receiving water bodies.In one of the plants, phosphate concentrations were found to be higher after treatment as compared to the influent concentration levels.This evidently showed that the wastewater infrastructure system was contaminating the wastewater within its unit processes.Introducing a Green Technology Model, the study explored the use of Pistia stratiotes and Chrysopogon zizanioides for effective contaminant removal, suggesting a viable integration of phytoremediation into existing wastewater systems to improve effluent quality and protect wetland ecosystems.The observed wastewater quality conditions and literature findings were used to inform the development and application of the Model in this study.The model results indicated that the Pistia stratiotes could be applied as a free-floating macrophyte suitable for the treatment of high phosphate, ammonia, and nitrate effluent, while the Chrysopogon zizanioides indicated significant potential in treating faecal coliforms and heavy metals through their root system.