Carbonized Briquettes as a Tool for Adding Value to Waste from Rain tree (<i>Samanea Saman</i>) and Coffee Ground/Tea Waste
The purpose of this research was to study the physical, environmental, and economic characteristics of carbonized briquettes from rain tree (Samanea saman) residues and coffee ground/tea waste with cassava starch (10% wt.). There were five treatments in this experiment. As a binder, 10%wt cassava starch was added to five ratios of rain tree residues to coffee ground/tea waste: RT100:CT0, RT75:CT25, RT50:CT50, RT25:CT75, and RT0:CT100. The physical properties of the carbonized briquettes were analyzed using ASTM methods. The results showed that the carbonized briquette made from 50% rain tree (Samanea saman) residues and 50% coffee ground/tea waste (RT50:CT50) had the highest calorific value (4,820.25 ± 9.97 Kcal/kg)—not significant at the 95% confidence interval—and highest shatter index (99.16 ± 0.20%). However, all ratios of rain tree residues to coffee ground/tea waste can produce carbonized briquettes for household use with convenience for transportation. In terms of economic performance, carbonized briquettes made from 50% rain tree (Samanea saman) residues and 50% coffee ground/tea waste (RT50:CT50) achieved the optimal payback period (approximately 6 months). Thus, making carbonized briquettes from rain tree residues and coffee ground/tea waste can be an alternative method of production to add value to biomass residue for use as raw materials to produce environmentally friendly fuel products.