For aquifer remediation purpose using techniques like PRB sources of pollution and their strength is required. In first section two permeable reactive barriers are simulated to check the spread of nitrate pollution in a heterogeneous anisotropic aquifer system. Finite element is applied to simulate wall and funnel type PRBs with one, two and three meter of PRB thickness and their effectiveness to reduce the nitrate below 45ppm at observation wells is examined. Cost comparisons are also made to suggest the most appropriate PRB to bring down nitrate concentration to desired limits. In the second section a rectangular and later a complex aquifer problem is simulated with finite element and differential evolution optimisation is used to find the location and load from polluting sources. Solutions are found satisfactorily. DE is appropriate for implicit, non-linear, non-differentiable and discrete objective function.