The objective was to evaluate the influence of particle size of the solid ground corncob and sugarcane bagasse, used as filter materials, the efficiency of removing pollutants from swine wastewater (SWW). It was used columns containing the filtering material in three particle sizes (0.84 to 1.19; 1.19 to 2.00 and 2.00 to 2.83 mm). To evaluate the efficiency of the system, the influent and effluent were characterized in relation to the following parameters: biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total solids (TS), total nitrogen (total-N) total phosphorus (total-P), potassium (K), sodium (Na), total copper (total-Cu) and total zinc (total-Zn). Curves were generated by relating the relative concentrations of the variables and the depth of the filtered SWW. The lowest concentrations of BOD in the effluent were obtained, in general, filters made of materials in its largest size; the removals of COD, TS, total-N, total-P were not significantly influenced by the size of the filter materials; the Na and the K had not been retained in the filter materials, in none of the grain sizes studied, however the removal of total-Zn and total-Cu were generally higher in filters consist of filter materials of smaller particle size.
organic filter; water treatment; particle size