The behaviour of residues of phenazone-type pharmaceuticals during bank filtration was investigated at a field site in Berlin, Germany, where bank-filtered water is used for drinking water production. The concentrations of the pharmaceutical residues in the shallow, young bank filtrate (travel times < one month) were correlated to the prevailing hydrochemical conditions at the field site. In addition, their behaviour during passage through an undisturbed sediment core from the lake base at the site (clogging layer) was evaluated in the laboratory. Phenazone, 4-acetylaminoantipyrine (AAA), 4-formylaminoantipyrin (FAA) and 1,5-dimethyl-1,2-dehydro-3-pyrazolone (DP) were eliminated more efficiently under oxic conditions, while 1-acetyl-1-methyl-2-dimethyloxamoyl-2-phenylhydrazide (AMDOPH) was not eliminated at all. The redox conditions and the elimination of the respective pharmaceutical residues displayed strong seasonal variations. Oxic conditions were only encountered close to the shore in winter, when temperatures were low. The column study showed that the elimination is restricted to the uppermost decimetres of the lake base, where oxygen is present. While phenazone elimination is almost complete during aerobic rapid sand filtration in the waterworks, the compounds were found to be more persistent under anoxic field conditions.

Managed aquifer recharge is gaining importance as a practice to bank and treat surface water for drinking water production. Neon (Ne) concentrations were analysed at four different recharge sites in and near Berlin, where groundwater is recharged directly from surface water courses, either by near-natural bank filtration, induced bank filtration or engineered basin recharge. Neon concentrations in excess of saturation (DNe) were used to identify excess air in the infiltrates. Excess air concentrations were around saturation at the near-natural bank filtration site, where river water infiltrates through a permeable river bed into a confined aquifer under completely saturated conditions. At two induced unconfined bank filtration sites, samples generally contained excess air (up to 60% DNe). Highest excess air concentrations (up to 81% DNe) were encountered at the engineered basin recharge site. The degree of water table fluctuations, the water saturation of the sediments in the infiltration zone and the presence of a confining layer affect the formation of excess air. Excess air can only be used to trace bank filtrate or artificially recharged water in a setting where the ambient groundwater in the near vicinity of production wells is not affected by large water-table fluctuations. Nevertheless, excess air concentrations provide valuable additional information on the type of recharge (saturated or unsaturated, degree of water table fluctuations).

Odours emerging from sewage networks are unpleasant, can cause health impacts on sewer workers and impair public perception of the operator companies. Corrosion is one of the causes for the cost of repairs for damages to wastewater systems in the public sewage network, which are rising extremely [DWA, 2004]. Both phenomena can have their origin in biogenic acid corrosion that is illustrated in this report. The Kompetenzzentrum Wasser Berlin (KWB) commissioned the Technical University Berlin and the Material Testing Institute of Berlin-Brandenburg to give a report on: • State of the art on control systems for odours and corrosion problems in sewer networks, (i) State of the art on sensor technologies for water, gas and corrosion parameters to follow corrosion and H2S production, (ii) Investigation on the feasibility to develop a three-phase model to predict the mass transfer of H2S from water to the gas phase and to the wall of the pipe through the biofilm and (iii) Elaboration of a draft of the functional and technical specifications for a sewer network pilot plant.

Tropical cyanobacteria in German waters: Causes and consequences - Toxic cyanobacteria of tropical origin have spread to water bodies in northern Germany. Here their population size is determined by the onset of germination: the earlier the time of germination, the larger the summer population. Climate-related early increase in water temperatures over the course of the years has promoted their spreading to temperate regions. Toxins known from these species in tropical regions were also found in German lakes. Surprisingly, these toxins are not produced by the invaders but by native species. Thus, the invasion have drawn our attention to an old problem. However, the invaders itself potentially also poses a health risk in German lakes since they produce other – so far unidentified – toxic substances.