Evaluating the Role of Feedstock Ratios and Binders in the Performance of Faecal-Derived Briquettes

The increasing population, demand, and high cost of domestic energy sources such as electricity and gas have heightened reliance on charcoal and other combustion fuels recently. This study analysed the performance of composite briquettes produced through briquetting processes. The briquettes were produced by different quantities of feedstock materials with two types of binders, namely cassava starch and paper pulp. The charred faecal sludge (FS) and sawdust (SD) were utilised as feedstock materials in varying ratios by weight (FS:SD) as 70:30, 60:40, 50:50, 40:60 and 30:70. Feedstock materials were densified by a cold manual press machine aided by two binder materials, namely cassava starch and paper pulp binding materials. Briquette performance analysis methods were deployed, including the water boiling test, the shattering index test, the water absorption resistance test and moisture content. The analysis of variance (ANOVA) was applied to analyse mean differences, and further, Fisher’s LSD test was used as post hoc. Results showed that the binding materials have more impact on fuel characteristics than the feedstock ratio. Cassava starch binder yielded a higher calorific value (24 MJ/kg) compared to paper pulp (13.75 MJ/kg), even though all briquettes met durability standards (shatter resistance >50%). The high calorific value of 24 MJ/kg briquette material was obtained from cassava binder briquettes, while all briquette samples passed through the shatter resistance test of above 50%. The study concluded that the use of faecal sludge-based briquettes for domestic energy applications is viable. However, to meet the same level of heating value as wood charcoal, one will need twice as many briquettes as the amount of charcoal. It is further recommended that the frequent use of briquettes should be in an open air environment to allow air circulation and avoid any potential health effects from air state conversions.