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

Abstract

The population increase, demand and high cost of energy sources such as electricity and gas in recent years increase charcoal and other combustion fuel dependencies. There is a need for rethinking and planning for alternative renewable energy sources. In this study, investigations were undertaken to analyze the produced composite briquettes through briquetting processes. The briquettes were produced by varying amounts of charred dried faecal sludge and sawdust as feedstock materials with two types of binding materials namely cassava starch and paper pulp. Faecal sludge (FS) and Saw dust (SD) char materials of different ratios by weight (FS: SD); 70:30, 60:40, 50:50, 40:60 and 30:70 was densified by a cold manual press machine using two binder materials. Different analysis methods were deployed including water boiling test, shattering index test, water absorption resistance test and moisture content to describe the physical properties such as density, strength and burning properties of briquettes. The analysis of variance (ANOVA) was applied to analyze mean differences and further Fisher’s LSD test as post hoc. Results showed that the binding materials have more impact to fuel characteristics than the feedstock ratio. The high calorific value of 24 MJ/kg briquette material was obtained from cassava binder briquettes while all briquette samples were 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 as briquettes amount than charcoal amount. It is further recommended that the frequet use of briquettes should be in an open air environment to allow air circulation and avoid any potential health effects from air states conversions