The biomass from a pilot-scale two-stage (carbon oxidation first stage, ammonia oxidation second stage) fixed-film biological aerated filter (BAF) was divided in three fractions depending on their attachment strength to the media: detached, easily detachable and strongly attached. VSS measurement showed that the detached and easily detachable fractions accounted for 25 to 40% of the biomass in the bed and are present even after backwash. Protein was the major constituent of all fractions of the biomass. The ratio of carbohydrate to protein differed between fractions and between type of biofilms, with a larger value for detached and detachable fractions and a lower value for a largely heterotrophic biofilm, implying a difference in the composition of the biomass matrix that could be related to the attachment state of the biomass. The biomass did not appear to be substrate-limited anywhere in the system, although the specific activity of the biomass was dependent upon the position in the column. Activity of the strongly attached biomass was less than 70% of the total activity, even after backwash. A mass balance on VSS showed that the backwash flushed a mass equivalent to less than 35% to 45% of the detached and detachable fractions, which was less than 15% of the total biomass present in the system. Data also suggested that during backwash, part of the strongly attached biomass was sheared off the media and regenerated the mass of biomass in the detached phase. In conclusion, it can be stated that a non-negligible part of the biomass in a BAF is in a detached state. Actual mechanistic BAF models based solely on biofilm modeling may be overlooking the role of that biomass, especially in the performance recovery of BAF systems after backwash. / Master of Science

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The effect of the pasture management on dung beetle communities was studied on three sites in Šumava Mts. (South and West Bohemia). The intensity of pasturing was different: 78 cattle on the first, 106 on the second and 162 on the third pasture. The beetles were collected using pitfall traps baited by 1.5 litres of fresh cattle dung. The traps were located on each pasture. Altogether 3 traps were used per each pasture. The pitfall traps were exposed in the pasture for 7 days in monthly repetitions from April to October 2008. Totally 8725 specimen and 33 species of beetles were collected. These species belong to families Scarabaeidae,Geotrupidae and Hydrophilidae. The number of species and individuals was evaluated for each pasture, as well as seasonal dynamics and biomass distribution. The results indicate that the more intensive pasturing has the positive effect on the activity of some groups of coprophagous beetles.Other effects of the different pasture management on the beetles were not documented.