Performance of a hybrid activated sludge/biofilm process for wastewater treatment in a cold climate region: Influence of operating conditions

a b s t r a c t The main aim of the study was to investigate a hybrid MBBR process, mostly in terms of organic matter removal and nitrification, when operating with different values of the mixed liquor sludge retention time (SRT), and highlighting the influence of temperature on the process. Based on experience in practice it was hypothesized that nitrification could be maintained at far lower SRT's than in conventional activated sludge systems and with high organic loading rates applied. A field gathering campaign has been carried out on a hybrid activated sludge/biofilm. The obtained results highlighted that the pilot plant was capable to remove the organic matter at loading rates up to 3…