# The Energy Potential, Environmental Impact, and Occupational Health and Safety Potential of Biogas Obtained from Filter Cake in Artisanal Panela Production

## TL;DR

This paper explores using filter cake from panela production in Ecuador's Amazon to generate biogas, reducing biomass use and environmental impact while highlighting health risks.

## Contribution

The study introduces a novel approach to valorize filter cake for biogas, quantifying energy and environmental benefits in the Amazon region.

## Key findings

- Biogas from filter cake can replace significant amounts of wood and bagasse in panela production.
- Biogas production conserves Amazon rainforest by reducing biomass use.
- High risks in handling filter cake and digestate were identified for occupational health.

## Abstract

Filter cake (or cachaza), a residue generated in the artisanal production of panela, represents an under-explored source of renewable energy in the Ecuadorian Amazon. Valorizing filter cake could reduce the use of solid biomass and emissions associated with traditional combustion. Our objective was to determine the energy potential of the biogas obtained and its contribution to the sustainability of the panela (unrefined cane sugar) production system. A sequential procedure was applied that included the physicochemical characterization of filter cake, feed flow modeling, and stoichiometric simulation under mesophilic conditions. The anaerobic digestion of filter cake with the optimal Composition 6 generated up to 1736.40 m3·day−1 of biogas with 40.7% methane and a calorific value of 14,350 kJ·m−3. This was enough to replace 1.24 t·day−1 of wood or 2.38 t·day−1 of bagasse in the production system. This represents an annual saving of 631.08 t of solid biomass, equivalent to conserving 3.63 ha·year−1 of the Amazon rainforest. The Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) analysis showed impacts on climate change (17.40 kg CO2 eq/m3) and acidification (0.00516 kg SO2 eq/m3), attributable to unburned methane and residual H2S. Meanwhile, the social assessment using the Occupational Health and Safety Potential (OHSP) indicator showed high risks in terms of handling filter cake and cleaning the digestate.