This research which is based on experimental work. devoted to study the improvement and stabilization of dune sands in order to create strong layer and stabilize slope and floor construction of sewage Lagoons. Materials used stabilizing these soils are residual oil from the refinery. To confirm the effectiveness of the use of residual oil to improve the mechanical properties of the sand. https://parisnaturalfoodes.shop/product-category/acidophilus-ultra/