The cases of drops and jets have been searched experimentally for various conditions in trickling filters and a relationship has been found with calculation between the unit flowrates and the specific surface areas. it is found that wastewater effects this relationship. in addition to this another relationship has been found between spherical materials and comered ones with the same specific surface. As a scientifical and economical conclusion, this study otiers some significant advantages such as optimum flow characteristic, optimum specific surface, optimum dimension of support material and increasing removal efficiency for trickling filler.