Performances d'un biofiltre à garnissage plastique pour le traitement d'effluents fortement contaminés en phénol, cadmium et chrome

The presence in domestic wastewater of high concentrations of organic and inorganic contaminants represents a serious problem for the treatment of these effluents. This research aimed to establish the performance of an aerobic biofiltration system with plastic packing for the treatment of effluents having high concentrations of phenol (300–500 mg·L^–1), Cd(II) (2.5–10.0 mg·L^–1), and Cr(III) (5.0–20.0 mg·L^–1). Six biofilter units were first started in batch mode and then operated in continuous mode under similar conditions. High removal yields were measured for chemical oxygen demand (98.3% ± 0.3%), phenol (100% ± 0%), Cr (99.3% ± 0.6%), and Cd (90.4% ± 0.8%) from a synthetic effluent initially containing 300 mg·L^–1 phenol, 5.0 mg Cr·L^–1, and 2.5 mg Cd·L^–1. Thereafter, the six columns were submitted to various operating conditions (hydraulic load, pH, phenol, cadmium, and chromium concentrations). This study showed that this system is efficient for the treatment of effluents having high concentrations of contaminants. To preserve a good efficiency of the system, the affluent must be kept at pH values equal to or higher than 6.0. Key words: biofiltration, phenol, chromium, cadmium, column, effluent, biomass, plastic.[Journal translation]