Faecal Sludge Treatment: Unveiling the Potential of the plant Panicum maximum

Abstract

This study evaluated the effectiveness of three plant species (Panicum maximum, Echinochloa pyramidalis, and Typha domingensis), in enhancing the removal of salinity, nitrogen, phosphorus, and chemical oxygen demand during sludge treatment within sludge treatment reed beds (STRBs). The experimental setup consists of 1 m³ tanks composed of sand and gravel, simulating the reed bed configuration. A total of twelve pilot-scale units were used, with each plant species tested in triplicate, while three units were used as non-planted (control) groups. Over a 6-month period, the units received weekly loadings of faecal sludge sourced from a site in southern Benin. Sampling was carried out weekly in order to evaluate the removal efficiency of the assessed parameters. The results showed the superior efficacy of STRBs compared to control beds, attributing this enhancement to the presence of vegetation. At a loading rate of 300 kg TS/m²/year, the system presented good performance. In particular, P. maximum and E. pyramidalis beds demonstrated the highest removal rates (Salinity: 97.95%, PO₄³⁻: 97.75%, TP: 98.08%, NH₄⁺: 98.68, NO₃⁻: 98.71%, TKN: 99.53%, TSS: 99.98%, COD: 99.94%). Moreover, the drying rates of E. pyramidalis and P. maximum beds (49.5% and 48.5%, respectively) surpassed those of T. domingensis beds (34.7%). These findings highlight the potential of P. maximum, a newly tested species, for application in STRBs, emphasizing the need for dedicated research on this species.