Predictive Modelling for Characterisation of Organics in Pit Latrine Sludge from Unplanned Settlements in Cities of Malawi

The limited availability of data on faecal sludge characteristics remains one of the major challenges faced by the developing countries in proper management of faecal sludge. Taking into account the limited financial resources and expertise, there is a need to come up with less resource intensive approaches for faecal sludge characterisation in these resource-constrained developing countries. Despite being used substantially in wastewater, there is a lack of evidence pointing towards the predictive modelling being used as a tool for cost-effective characterisation of faecal sludge. In this study, first order multiple linear regression models are developed as a cost-effective approach for accurate predictions of organics (biochemical oxygen demand and chemical oxygen demand) in pit latrine sludge. The predictors explored during the modelling include pH, electrical conductivity, total solids, total volatile solids, fixed solids and moisture content. The models are built using the data collected from a total of 80 latrines from informal settlements in four cities in Malawi. The results for the models show that it is possible to reliably predict the chemical oxygen demand and biochemical oxygen demand in pit latrine sludge using the electrical conductivity and total solids, the determination of which requires low levels of resources and expertise