Characterisation of faecal sludge simulants for drying experiments

In order to optimize the drying process in covered, unplanted sludge drying beds more testing on faecal sludge drying and dewatering is required. Using real faecal sludge for drying and dewatering experiments is often not viable given the health and safety risk and its high variability. Following a thorough literature review of current synthetic simulants, an existing simulant (PRG, 2014) was prepared and tested to characterise its drying and dewatering behaviour in relation to real faecal sludge. It was found that the recipe proved robust to alterations and exhibited similar chemical characteristics as real faecal sludge; however, it was unlike real faecal sludge in terms of consistency and colour. It is concluded that further investigation is required to develop a synthetic simulant that replicates the chemical, physical and thermal properties of real faecal sludge for drying and dewatering experiments.