Assessing the effectiveness of electromagnetic surveying techniques to determine the extent of buried waste in small trench-and-fill landfills

To properly manage the challenges of small legacy landfill operations in remote areas such as Northern Ontario, it is important to accurately delineate areas of buried waste. A proper delineation of buried waste is required for site life calculations, future development planning and site closure planning. Traditional methods of waste delineation, such as test pitting, can be destructive, expensive and limited by poor site access. This study aims to delineate buried waste at three separate trench-and-fill style landfills using a Frequency-Domain Electromagnetics (FDEM) survey. The results of the FDEM survey were compared to the results of concurrent traditional test-pitting programmes. The EM31-MK2 was successful in accurately determining the lateral extents of buried waste compared to the results of the test-pitting programme. Other geophysical survey methods, used with FDEM surveys, may improve measurements of waste thickness. The calculated areas of buried waste from the FDEM survey were within 6% of the calculated area from the test-pitting programme, with the exception of one site with a large area of thin buried waste. The calculated volumes of waste using the FDEM survey were within 15% of the calculated volumes of waste using the test-pitting programme. Additionally, the area of waste delineated by the FDEM survey had a 70% overlap with the area of waste defined by the test-pitting programme. The accurate delineation of buried waste, combined with the manoeuvrability and ease-of-use of the EM-31 MK2, make it an effective tool for lateral waste delineation at small landfilling sites.