The interest in natural surface-water treatment techniques such as bank filtration and artificial ground water replenishment has increased with the growing worldwide need for clean drinking water. After detecting a number of pharmaceutical residues in groundwater samples from a bank filtration site in Berlin, Germany, the research on these compounds has focused on investigating their transport behavior during the infiltration process. In the studies presented in this paper, the fate of six pharmaceutical residues detected at concentrations up to the µg/L-level in Berlin’s surface waters was investigated. During bank filtration, the analgesic drugs diclofenac and propyphenazone, the antiepileptic drugs carbamazepine and primidone and the drug metabolites clofibric acid and 1-acetyl-1-methyl-2-dimethyl-oxamoyl-2-phenylhydrazide (AMDOPH) were found to leach from the surface water into the groundwater aquifers. They also occur at low ng/Lconcentrations in the receiving water-supply wells. Other compounds namely the antiphlogistic drug indometacine and the blood regulating drug bezafibrate which are also detected at concentrations up 100 ng/L in the surface water are efficiently removed by bank filtration. Thus, they have not been detected downstream of the first two monitoring wells. In conclusion, bank filtration was found to decrease the concentrations of some drug residues (e.g. of diclofenac, carbamazepine) or even to remove selected compounds (e.g. bezafibrate, indometacine). However, a complete removal of all potential pharmaceutical residues by bank filtration cannot be guaranteed.

In the course of the interdisciplinary research project NASRI (natural and artificial systems for recharge and infiltration) many investigations are currently being carried out to assess the risk of break through of persistent organic substances into raw water used for drinking water supply. One part of these studies is the determination of the transport behavior of pharmaceutical residues in test sand filters, so called enclosures, equipped with sampling points at various depths. Breakthrough curves were determined for carbamazepine, primidone (both antiepileptic drugs), clofibric acid (a metabolite of blood lipid lowering agents), diclofenac, ibuprofen (both analgesic drugs) and for chloride, used as a conservative tracer. Retardation coefficients and degradation rates were obtained by using the software Visual CXTFIT. Degradation rates between 0.7 h–1 and 1 h–1 were observed for ibuprofen whereas clofibric acid, primidone, carbamazepine and diclofenac showed no or very little degradation (lambda < 0.06 h–1).

This paper presents the results on the occurrence and fate of antibiotic residues during bankfiltration obtained from a study carried out in terms of an interdisciplinary project at three transects in Berlin, Germany. Six antibiotic compounds and two metabolites were detected at ng/L concentrations in water samples from the lakes or in the monitoring wells of the transects. Clarithromycin, roxithromycin (macrolide), trimethoprim (synergist for sulfonamides) and acetyl-sulfamethoxazole (metabolite) are efficiently removed by bank filtration. Residues of clindamycin (lincosamid) and dehydro-erythromycin (metabolite) were completely attenuated during the soil passage. For sulfamethoxazole (sulfonamide), a significant but not complete removal during bank filtration was observed. It was the only compound that could be detected at tracelevels in samples collected from water-supply wells.

Residues of pharmaceuticals used in human medical care have recently been detected as important trace contaminants of sewage, surface and groundwater. This paper compiles the recent state of knowledge on the occurrence and fate of pharmaceutical residues in the aquatic environment of urban areas. Findings in sewage effluents, surface, ground, and drinking water at concentrations up to the µg/L-level have been reported and will be discussed to demonstrate the impact of pharmaceutical residues on the aquatic environment and on public water supply. The efficiency of natural and technological processes such as bank filtration or membrane filtration for the removal of pharmaceutical residues including estrogenic steroids, analgesics, antibiotics, anti-epileptic drugs, blood lipid regulators, and several drug metabolites will be presented and discussed.

Bank filtration and artificial ground water recharge are important, effective, and cheap techniques for surface water treatment and removal of microbes, as well as inorganic, and some organic, contaminants. Nevertheless, physical, chemical, and biological processes of the removal of impurities are not understood sufficiently. A research project titled Natural and Artificial Systems for Recharge and Infiltration attempts to provide more clarity in the processes affecting the removal of these contaminants. The project focuses on the fate and transport of selected emerging contaminants during bank filtration at two transects in Berlin, Germany. Several detections of pharmaceutically active compounds (PhACs) in ground water samples from bank filtration sites in Germany led to furthering research on the removal of these compounds during bank filtration. In this study, six PhACs including the analgesic drugs diclofenac and propyphenazone, the antiepileptic drugs carbamazepine and primidone, and the drug metabolites clofibric acid and 1-acetyl–1-methyl–2-dimethyloxamoyl– 2-phenylhydrazide were found to leach from the contaminated streams and lakes into the ground water. These compounds were also detected at low concentrations in receiving public supply wells. Bank filtration either decreased the concentrations by dilution (e.g., for carbamazepine and primidone) and partial removal (e.g., for diclofenac), or totally removed PhACs (e.g., bezafibrate, indomethacine, antibiotics, and estrogens). Several PhACs, such as carbamazepine and especially primidone, were readily transported during bank filtration. They are thought to be good indicators for evaluating whether surface water is impacted by contamination from municipal sewage effluent or whether contamination associated with sewage effluent can be transported into ground water at ground water recharge sites.

The spatial distribution of confining layers within a system of two aquifers strongly affects the hydraulics and sensitivity to pollution. The test site is located close to a well field. Wells are switched with short intervals and hydraulic heads are recorded in several observation wells. Because the absolute levels of simulated hydraulic heads do not always coincide with the measurements, the model is calibrated with short term head variations. The characteristic shape of the hydraulic heads at each observation wells contains sensitive information about the structure of the aquifer. A numerical technique is developed which enables to simulate the spatial distribution of the confining layer. The method comprises the use of pilot points and regularisation technique. Cross validation is carried out in order to show the results are physically based. The method is shown to provide significant results even under non optimal conditions.