Assessment of swine wastewater treatment systems and statistical modeling of operational parameters for anaerobic digester monitoring

This study assessed wastewater treatment practices on swine farms in Pará de Minas, Minas Gerais, Brazil, and investigated statistical models to support the monitoring and operational control of anaerobic digesters. Six farms representing different production settings were surveyed to characterize their wastewater treatment systems, with particular emphasis on anaerobic digestion and biogas recovery. In a complementary experimental phase, laboratory-scale experiments were conducted to investigate relationships among process parameters and develop statistical models for monitoring digester performance. The findings revealed considerable potential to expand regional biogas production through wider adoption of anaerobic digesters and improved operation of existing facilities. However, additional technological investment is needed to support smaller farms, strengthen process monitoring, and improve wastewater treatment and biogas production efficiency. Among the evaluated relationships, the model linking pH to intermediate and partial alkalinity ratio showed the most satisfactory statistical performance, with residuals below 1 and no detected violations of the assumptions assessed. In contrast, the model relating pH to soluble phosphorus was limited by non-normal residuals and a smaller sample size. These results highlight the need to adapt statistical models to local operating conditions, incorporate additional explanatory variables, and apply robust validation procedures. Overall, the proposed approach combines field assessments with laboratory-based statistical analysis to inform anaerobic digester monitoring. With further validation under full-scale operating conditions, its application may help improve operational decision-making, promote more efficient biogas recovery, and support environmentally sustainable wastewater management in swine production systems.