Characterizing landfill extent, composition, and biogeochemical activity using electrical resistivity tomography and induced polarization under varying geomembrane coverage

Landfill monitoring is essential for sustainable waste management and environmental protection. Geophysical methods can provide quasicontinuous spatial and temporal insights into subsurface physical properties and processes in a nonintrusive manner. The effectiveness of monitoring landfill extent, composition, and degradation under varying geomembrane coverage is evaluated using electrical resistivity tomography (ERT) and induced polarization (IP) methods. Synthetic electrical models for landfills with different geomembrane damage degrees are inverted to assess data reliability. The current conduction channels into the geomembrane during the electrical survey are quantified. Reliable electrical data are obtained when the inverted conduction channel ratio of the geomembrane (representing the damage to the geomembrane) is 51.6% or higher. This criterion is validated in a landfill experiencing aeration and anaerobic treatments. ERT and IP data capture construction and domestic waste distribution and identify the landfill boundary. The chargeability of domestic waste proves sensitive to microbial degradation activity, corroborated by characteristic ammonium and nitrate ions and a linear relation between chargeability and subsurface temperature. Temperature variations between the aerobic and anaerobic reaction zones (>20°C and ≤12°C) are observed to correlate with high chargeability values (>80.4 mV=V), signifying the presence of biogeochemically active zones. IP excels in characterizing geomembrane-covered landfill boundaries and discerning biogeochemical activity, thereby enhancing landfill monitoring and waste management strategies.