Spread of landfill leachate into groundwater

Many landfills built a few decades ago do not meet modern requirements. In this regard, leaks in landfills occur, that have a negative impact on the environment and especially on water objects. The aim of the work is to determine the infiltration rate of landfill filtrate taking into account the natural and climatic conditions on the example of the landfill “Novyye Cherkassy” (Ufa, Russia). The HELP program is used to simulate the leachate infiltration through existing landfill layers. To simulate the movement of a toxic liquid seeping through the waste layer into the soil profile, the HYDRUS program is used. Results of 10 years hydrologic evaluation by HELP program showed that the volume of filtrate formed is 341 m3/day. Comparison of the result obtained with the works of other authors showed that the increased filtrate value is due to the landfill age (the landfill is as old as 56 years) and the lack of protective measures for prevention infiltration into the soil. The seasonality in the leachate formation at the landfill is revealed. There is no leachate in the winter (negative temperature) but in the spring volley receipt caused by snowmelt (positive temperature) occurs. In the summer months, evapotranspiration was about 77% of the total precipitation, while infiltration did not exceed 7%. In the autumn month's evapotranspiration was only 30-40%, while infiltration increased up to 16%. The calculations showed that during landfill operation toxic mass has spread over 7 km. To prevent further environmental impact, it is necessary to close the landfill or remediate it.