Hydraulic distribution effect on a real-scale trickling filter

In this work, the influence of several operational parameters on the efficiency of a real-scale trickling filter placed in an urban wastewater treatment plant in Mexico, is discussed. Special attention is placed on the parameters that influence the biofilm hydraulics such as the instantaneous dosing intensity (SK) and the radial distribution of the superficial hydraulic load. The low speed of the distribution arms forced an instantaneous dosing intensity of 150 mm/pass, resulting in a short liquid retention time of 32 s, which was the reason why a poor COD removal efficiency was obtained. The average removal is 36%, although the daily efficiencies increase with increasing inlet COD concentrations. However, the high shear forces of the water provides a constant and homogenous biofilm detachment, avoiding filter clogging because of the solids. Finally, a slight decrease in the theoretical efficiency has been found due to a nonuniform radial distribution of flow, because the real superficial load is too high in the center of the filter.