Introduction: In coffee production, wastewater generated during the pulping process show a high organic load, which represents an environmental risk to receiving water bodies when discharged without prior treatment
Objective: To optimize the treatment of wastewater from the wet processing of coffee through a batch electrocoagulation process using aluminum electrodes.
Methodology: A Plackett-Burman design was applied to identify the operational variables with the greatest influence (pH, temperature, salt concentration, electric current, stirring speed, and reaction time). Subsequently, the significant variables were optimized using a Box-Behnken design and response surface methodology.
Results: Under optimal conditions, a quadratic model was developed to describe biochemical oxygen demand (BOD₅). The estimated treatment cost was 24.02 MXN·m^-3, considering both energy consumption and electrode wear. The BOD₅ removal efficiency reached 98.5 %, a value consistent with the model prediction (97.49 %), which showed a good fit to the data (R² = 0.911).
Limitation of the study: The study did not include variability among different coffee harvests.
Originality: The proposed treatment represents an innovative alternative in the study region, with high efficiency in the removal of organic load.
Conclusions: The treated wastewater presented BOD₅ concentrations below 20 mg·L^-1, which complies with the criteria established by NOM-003-SEMARNAT-1997 and allows its potential reuse for irrigation of coffee plantations.