This study aims to determine the optimal concentration and soaking duration of banana flowers in lime water to produce high quality chips, as well as to analyze the financial feasibility of the production process. The study uses a Completely Randomized Design with two factors: the concentration of lime water (P) and the soaking time of banana flowers in lime water (L). The result showed that the best quality banana flower chips were obtained by soaking for 30 minutes in a 5% lime water concentration. The chips had a moisture content of 14.96%, crude fiber content of 2.49%, and ash content of 5.75% and in the preference test, with scores for taste (4.9), texture (4.7), color (4.75), and smell (4.5).

The utilization of rice husk in Indonesia concentrate to low economic value products, while this biomass waste has significant potential for various higher-value applications. This study aims to analyze material flow (Material Flow Analysis) and calculate the carbon footprint of the rice husk biochar production process using pyrolysis methods. The pyrolysis techniques employed were slow pyrolysis and fast pyrolysis at the Renewable Energy Laboratory of Tribhuwana Tunggadewi University. This study shows that the slow pyrolysis method with 30.05 kg of rice husk input and 0.6 kg of water produces 38.2% biochar yield, while fast pyrolysis with 0.5 kg of rice husk input without water produces a yield of 40.6%. Carbon trail analysis revealed that in slow pyrolysis, of the total carbon input 0.971 kg only 0.674 kg identified in the final product (BioChar 0.410 kg, Bio-Oil 0.250 kg, gas 0.014 kg), while fast pyrolysis of the total carbon input of 3.003 kg produces 1,1532 kg carbon in the final product (biochar 0.415 kg, bio-il 0.5656 kg, gas 0.1726 kg), with electrical energy consumption that produces emissions of 1,983 kgCO2e. Pyrolysis technology has proven to convert rice husks into high -value BioChar, with fast pyrolysis shows a higher yield and better process efficiency without the addition of water. Although fast pyrolysis produces higher emissions, slow pyrolysis with the use of residual gas is more recommended for regions with limited electricity networks.