Simulation of Contaminants Transport and Groundwater Flow for Basrah Landfill Site

Abstract

groundwater aquifers is mostly effected from landfills due to intrusion of leachate from its base b. Active surface of landfills represents main source for leachate generation during rains or may be due to direct contact with groundwater, leading to the transport 5 pollutants from landfill which is intrudes to the aquifer under the landfill. In this research a 3-dimensional simulation models was constructed and calibrated to characterize groundwater flow and leachate pollution transport from Basrah province main landfill site. The selected study area is Al-Rafdhia landfill site, which is lie at Al-Zubair district (southern part of Iraq at Basrah). The model used in the simulation was Visual MODFLOW finite difference approach. All the required landfill and aquifer parameters, stressing and recharge estimates from field and laboratories works, Basrah climate data, observations, soil investigation reports and previous studies for the same region and then used in the model or adjusted by calibration. Six-month observation period was achieved to estimate the monthly state variables data such as heads and physical-chemical leachate and groundwater characteristics by measurement and sampling from the groundwater selected wells. Many soils and water samples were collected to know the aquifer characteristics and analyze the pollutants concentration values. Accordingly, the calibrated model was used to simulate the flow and pollution transport at current year and then used for prediction of future changes in water levels and landfill contaminant transport in the aquifer for planning period of 15 future years. The final simulation and predication results show that the landfill represent main source of contamination and the pollution would occur in the aquifer at high levels and with approximate lateral transporting of 285 m/year if the current state of solid waste disposal continue with increase of pumping from the aquifer from its current rate with future. The groundwater flow and concentration profiles for pollutants with time and spaces from the pollution sources was predicated and a 3-D representation were done for pollutants spreading for specific pollutants.