Evaluation of the Use of Filter Beds with Bioclastic Granulate at Pilot Scale for Phosphorus Removal in Sewage Post-Treatment

Objective: To evaluate the use of filter beds with bioclastic granulate at pilot scale for phosphorus removal in sewage post-treatment. Theoretical Framework: Demand for sustainability highlights the use of the bioclastic granulate Lithothamnium calcareum in the removal of phosphorus and metal ions from wastewater, with low cost and diffuse pollution control. Method: The pilot-scale system for phosphorus removal was implemented at the outlet of an activated sludge wastewater treatment plant. Cylindrical filters were installed in parallel, with a diameter of 110 mm and bed heights of 30, 40, and 50 cm (F1, F2, and F3). The bioclastic granulate bed was fractionated using 4.75 and 1.0 mm sieves. Filters operated for four days under an average flow of 1.90 L·min⁻¹. Bed density and porosity of the media were determined. Total phosphorus concentrations were monitored at the inlet and outlet of each filter during the operation period. Results and Discussion: Maximum hosphorus removal efficiencies were 51.38% in F1, 54.72% in F2, and 62.50% in F3. Filter F3 maintained its adsorption efficiency throughout the operation. The pilot-scale evaluation demonstrated the feasibility of using bioclastic granulate for phosphorus removal in sewage post-treatment systems based on the activated sludge process. Research Implications: Enables commercial filter development and evaluates agricultural reuse of phosphorus-saturated media.