Large‐scale anaerobic/aerobic treatment of complex industrial wastewater using immobilized biomass in fluidized bed and air‐lift suspension reactors

Warm concentrated industrial wastewaters are preferably treated in an anaerobic reactor for reasons of energy generation and low surplus sludge production. Problems to be solved in the practical application concern a low growth rate of the micro‐organisms, their low settling rate, process instability and the need for after treatment of the noxious anaerobic effluent which often contains NH and HS−. The use of biomass immobilized on small suspended carriers (< 0.5 mm) has proven to be a suitable means to overcome most of these problems. Results are presented on pilot and full‐scale pretreatment of industrial wastewater in an anaerobic 2‐state fluidized bed reactor for CH4‐production and laboratory and pilot scale post‐treatment of the anaerobic effluent, which contains NH and HS− in an aerobic air‐lift suspension reactor for the production of NO and SO .