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 domin- gensis), 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 param- eters. 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.