The effect of seasonality in biogas production in full-scale UASB reactors treating sewage in long-term assessment

Abstract

Bioenergy is generated from anaerobic reactors treating domestic sewage. Nonetheless, for process optimisation a better understanding on the reactor performance and environmental conditions is required for designing equipment and identifying the optimal downstream conversion. This work aims at identifying the influence of seasonality in the biogas production of two full-scale STPs. Data analysed showed how rainfall events were associated with an increase (5–9%) in sewage influent flow, which led to dilution in the organic loading rate and, consequently, a decrease in biogas production (10–20%). This impairs the electric power generation potential in the monitored STPs up to 20%, compromising energy recovery for electricity. On the other hand, temperature did not show a significant influence (18–25°C).

Keywords

• biogas
• sewage
• anaerobic digestion
• renewable energy