Decolorization of Reactive Orange 16 in Rotating Drum Biological Contactor

A laboratory scale Rotating Drum Biological Contactor (RDBC; drum length × diameter: 255 × 130 mm) filled by randomly arranged particulate carriers with mycelium of the white rot fungus Irpex lacteus was tested for Reactive Orange 16 (RO16) decolorization. Five mycelium carriers were pre-screened for fungus immobilization and the dye degradation in static cultures. The best mycelium growth was observed with the straw, wooden shavings and polyether foam cylinders. Considerable dye adsorption (up to 30%) was observed with natural carriers; very low adsorption was observed with carrier particles made of plastics. Natural mycelium carriers with attached I. lacteus yielded the highest RO16 decolorization efficiency (50–90%). The straw, wooden shavings and polyether foam particles were tested in the RDBC in batch dye degradation experiments and the straw was also tested in continuous experiments. The straw yielded the fastest and stable dye decolorization in the subsequent batches. With the straw, wooden shavings and polyether foam particles RO16 decolorization higher than 90% was achieved within 48 h in batch experiments and better than 80% decolorization was attained at liquid mean residence time of 33.3 h in continuous experiments. Dye degradation rate of 3.5–4.0 g m−3 h−1 was achieved in the batch RDBC and the rate of 1.1–1.5 g m−3 h−1 in the continuously operated reactor.