Reduction of carbon and water footprints in wet coffee processing and optimization of wastewater treatment at the wet mill factory

With increased coffee production and consumption globally, the coffee industry is gradually embracing a circular economy to curb high carbon and water footprints. Currently, coffee consumption has become part of our daily lives. However, wet coffee processing and coffee wastewater treatment stages are a major source of carbon emission and high-water footprint. This study is designed to evaluate and mitigate carbon and water footprints in wet coffee processing and optimize the coffee wastewater treatment process at the wet mill factory. The results show that from 2019 to 2023 wet mill B had the highest mean carbon and water footprints at (4707.28 t CO₂-e & 9880.47 m³) as compared to wet mill A (1867.58 t CO₂-e & 3917.62 m³) and wet mill C (2788.48 t CO₂-e & 5844 m³) respectively. The major source of carbon emission was wastewater generation (99 %) while water footprint was the pulping, washing and fermentation stages (99 %). The optimization of coffee wastewater treatment technology by the integration of constructed wetland has the potential to reduce COD and BOD concentration by 80 %. The use of efficient fermentation methods, treated wastewater reuse, biogas capture and conversion to clean energy and automation of wet coffee processing can reduce carbon and water footprints.