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.

In Berlin, 70 % of the drinkinq water is derived from bank filtrate or artificially recharged water. Because the surface water system contains elevated proportions of secondary treated municipal sewage, a number of sewage indicators from various sources can be detected in the bank filtrate. An artificial recharge site and a bank filtration site in Berlin Tegel are introduced and compared in terms of their hydrogeological and hydrochemical properties. Because of a permanent clogging layer and the geological properties, travel times are slower at the BF site and the hydrochemical conditions are more reducing. First estimates for the reaction rate constants of oxygen and nitrate are obtained with exponential data fitting. Some of the effects of the different redox conditions on minor substances such as drug residues are highlighted.

Simulation tools help develop an integrated approach for Berlin’s combined sewage system in which sewage overflows pose risk to groundwater and surface water quality

The effect of oscillating pumping regimes at the bank filtration site in Berlin Tegel is examined via a scenario based modelling study. There are several scenarios for the pumping regimes, some adopted from the operation of the plant by the Berlin Water Works (BWB), some hypothetical with a regular oscillating regime. A horizontal 2D model of the lower aquifer is set-up, in which the third type boundary condition is used to mimic the influence of an irregularly shaped till layer, overlying the main aquifer. Model results in form of flowpaths are presented for several pumping scenarios. They reveal that there is a substantial influence of the pumping regime on the flowpaths in the vicinity of the well gallery, while in the farfield, including the bank of the surface water body (here: Lake Tegel) the oscillating effect is rather small. It depends very much on the infiltration position on the bank, whether traveltime through the aquifer changes as effect of irregular pumping.

The effect of oscillating pumping regimes at the bank filtration site in Berlin Tegel is examined via a scenario based modelling study. Several scenarios for the pumping regimes are calculated, some adopted from the operation of the plant by the Berlin Water Works (BWB), some hypothetical with a regular oscillating regime. Two of these are presented here. A horizontal 2D model of the lower aquifer is set-up, in which the third type boundary condition is used to mimic the influence of an irregularly shaped till layer, overlying the main aquifer. Model results in form of flowpaths are presented for several pumping scenarios. They reveal that there is a substantial influence of the pumping regime on the flowpaths in the vicinity of the well gallery, while in the far field, including the bank of the surface water body (here: Lake Tegel) the oscillating effect is rather small. It depends very much on the infiltration position on the bank, whether traveltime through the aquifer changes as effect of oscillating pumping regime.

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.

Since the 1970s we know about the idea of real-time control of urban drainage systems. Anyway, global real-time control strategies still show a lack of implementation for large drainage systems of high complexity. In Berlin, Germany, a city of 3.5 million inhabitants covering an area of around 900 km², the demand for enhanced protection of the environment and the growing economic pressure have led to an increasing application of control assets and concepts within the sewage system. In the framework of the project “Integrated Sewage Management” the possibilities of a global and integrated control strategy for the Berlin system are examined. The paper is focused on the historical concept and design of the sewerage and the further improvement towards an environment-oriented system that builds the basis for today’s considerations. The operational method and functionality of local regulators that have already been implemented are described. Further more the model-based methodology for the analysis of the system and the development of global control concepts as well as results of system analysis are stated. On the basis of model simulations it is shown that a global coordination of pump stations can lead to a reduction of sewer overflows and consequently to an enhanced water protection.

The paper introduces an algorithm for a level dependent real-time control of sewage pump stations and states results from its evaluation based on a spectrum of simulations for three different catchments of the Berlin drainage system. The objective of the control function is to smooth the delivery of the pumps towards the wastewater treatment plant during storm weather events by throttling the flow and implicitly activating inline retention capacities of the sewer networks. The article comprises the definition and functioning of the control concept as well as operational constraints and boundary conditions and the derivation of optimal control parameters. The simulation-based evaluation of the concept shows that it is possible to manage available inline storage volume by applying the control function. However, only if an adequate retention volume of around 50.0 m³/ha Aimp or more is available a significant improvement of the flow characteristic towards the wwtp is possible.