Experimental investigation on the migration of leachate under flowing conditions through laboratory ERT

With an increase of service time of landfills, a great amount of old landfills begin to leak and the leachate impairs the surrounding environment severely. Defining the flow of leachate is significant to the monitoring and restoration of the landfill. Field tests and laboratory tests are often used to investigate the leachate flow. However, many uncontrollable factors may affect the accuracy of field tests, and the application of field test results is usually limited. At the same time, it is difficult to simulate and monitor the migration process of leachate in real time in laboratory. To address this problem, a new physical simulating device is created to simulate the leachate migration under flowing conditions, and improved ERT device is designed to monitor the migration in laboratory tests. The results show that the improved ERT could delineate the migration range well in laboratory tests, providing a new method to investigate the leachate migration in laboratory test and providing a reference to the application of ERT in field tests. The relative variation rate of resistivity could reduce the influence of background, and is very suitable for time-lapse ERT. In addition, the effect of flowing rate, leakage rate, and time on the leachate migration is also investigated. The results show that the horizontal migration rate increases with an increase of flowing rate. The leakage rate has a significant influence on the vertical migration, but has limited effect on the horizontal migration. The curvature of migration front increases with an increase of flowing rate and time.