Monitoring municipal solid waste biodrying processes using electrical resistivity tomography: insights for enhanced efficiency

The management of municipal solid waste in developing countries presents significant challenges due to the waste’s high moisture content. Biodrying is an effective approach to reducing moisture in organic waste, thereby improving its calorific value. This study explores the application of electrical resistivity tomography to monitor the municipal solid waste biodrying process, which enables real-time, spatial tracking of key parameters, including moisture content and temperature. Here, a biodrying reactor was used to process 240 kg of municipal solid waste over 12 days. Electrical resistivity tomography measurements were collected continuously alongside temperature, gas emission, and settlement data. The moisture decrease was also strongly correlated with increasing bulk electrical resistivity, which rose from 294 Ωm initially to 763 Ωm at the end. Peak microbial activity was observed on day 7.5 when the reactor’s temperature reached its maximum (63 °C). This study identified a strong correlation (r >  ± 0.7) between electrical resistivity and temperature, as well as between electrical resistivity and gravimetric moisture content. The electrical resistivity tomography measurements provided spatial distribution data that revealed moisture and temperature gradients within the reactor, thus optimizing the biodrying performance. These findings demonstrate the potential of electrical resistivity tomography as a monitoring tool for enhancing biodrying processes, which can increase the energy recovery potential of municipal solid waste.