5. Conclusion. In light of the above results, the valorization of sand dune resources used as a filtering support in the treatment of wastewater represents a promising alternative for the development of large-scale pilots. Indeed, this choice would enable to minimize resorts to costly techniques that require the implication of huge means of management and maintenance. The proposed experimental device was constituted of pilots containing a bi-layer fixed bed made of an appropriate mixture of activated carbon and sand dune. An important elimination efficiency of organic matter has been obtained. The chemical and biochemical oxygen demand yields are respectively 97.7 % and 99%. The study of the filtration efficiency, in the present case, seems to be a powerful mean for the evaluation of local materials especially for water quality improvement and the preservation of the environment.