Purpose: The transport behavior of human pharmaceuticals in groundwater depends on a multitude of factors such as the physico-chemical conditions in the aquifer and the organic carbon content of the sediment, and, in particular, on the redox conditions in the groundwater. This is of special interest at managed aquifer recharge sites where the occurrence of trace organics is important for drinking water production. The aim of this study was to evaluate the possibility of influencing the redox system of the aquifer in a way that optimizes the potential of managed aquifer recharge systems to reduce the amount of trace organics. Materials and methods: Column studies were performed using natural and thermally treated sediments from an infiltration basin of the Berlin area, Germany. Special emphasis was placed on thermal treatment of the sediments to influence the total organic carbon (TOC) content in the sediment. In one experiment, the sediment was thermally pretreated at 550 °C, in two experiments the sediment was pretreated at 200 °C, and in one the sediment was untreated. Furthermore, the influence of ozonation, a very common disinfectant used in drinking water production, was studied in the experiments. The retardation and degradation parameters for primidone (PMD), carbamazepine (CBZ), and sulfamethoxazole (SMX) under different redox conditions were evaluated. Results and discussion: Oxic conditions were obtained in the experiment with low TOC (0. 06 wt%) in the sediment pre-treated at 550 °C. Anoxic conditions were predominant in two column experiments with a TOC content of 0. 17 wt% in the sediment, irrespective of the mode of treatment (natural or 200 °C). All three pharmaceutical compounds show almost conservative transport behavior with retardation factors between 1. 02 and 1. 25 for PMD, between 1. 06 and 1. 37 for CBZ, and between 1. 00 and 1. 08 for SMX. Differences in the transport behavior were observed depending on the TOC content of the sediment. For CBZ, and to a minor extent for PMD, the higher retardation factors were observed in the sediment with a TOC content of 0. 17 wt% under anoxic conditions. The ozonation of the influent water affects the influent concentrations of PMD, CBZ and SMX. However, it has no influence on the oxygen concentration of the column outflow. Conclusions: CBZ and PMD are retarded in the presence of organic matter in the aquifer. Variations of the TOC content of the sediment have a direct influence on the retardation of CBZ and PMD. The three human pharmaceuticals may be ranked in order of decreasing retardation: CBZ & PMD & SMX. The microbial activity in the experiments was not studied, although it can be assumed that the thermal pretreatment influences the microbial activity in the sediments. In particular, the microbial activity was severely inhibited at 550 °C, resulting in a shift of the redox conditions.

The present study provides an overview of geogenic contamination, its occurrence, impacts and possible treatment options for drinking water production. Natural background and anthropogenic contamination can be differentiated using an algorithm based on the frequency distribution of measured substance concentrations. Case studies for geogenic contaminants such as ammonium, fl uoride, chloride, sulfate and uranium are discussed based on the origin, occurrence, controlling factors and treatment options. It is suggested that, in case of occurrence of geogenic contaminants, water must be treated or alternative sources need to be found, e.g., managed aquifer recharge, prior to the distribution as drinking water.

Wastewater reuse is increasingly considered as possible alternative water source for diverse non-potable uses. Among the major questions, defining which water quality for which reuse is required is crucial. If the demand for reclaimed water is seasonal, the question of reclaimed water storage is also essential. Aquifer recharge for further nonpotable reuse can be a solution to address many final reuse applications, including indirect agricultural or landscape irrigation, saltwater intrusion barriers, subsidence mitigation/aquifer replenishment or other non-potable reuses. Most of the aquifer recharge applications of wastewater reuse so far rely on high-pressure membrane systems or even double-membrane combined with advanced oxidation processes. However, when non-potable reuse is targeted, or the replenishment of a threatened aquifer is planned, recharge with high-quality non-potable water could be envisaged as acknowledged by the legislation of several countries. In this report, the performance of hybrid disinfection/filtration and recharge schemes is assessed in comparison to a high-pressure membrane system working under similar conditions. Among the portfolio of available disinfection and filtration technologies, five treatment trains were chosen – combinations of ozone or UV treatment with sand filters or UF membrane and final infiltration or injection – and compared to a double-membrane system (UF+NF). A synthetic secondary effluent (SE) was considered for this conceptual study on the basis of a worldwide survey of typical SE water qualities. The major legislations from the WHO, the USEPA and Australian guidelines were considered to define the water quality to be reached by these hybrid treatment schemes. The low targeted value in suspended solids (10 mg/L) and microbiological contaminants (1 fecal coliform / 100 mL) requires extensive disinfection and filtration processes. The proposed schemes were selected on the base of a large review of typical pollutant removal efficiencies found in the literature. To perform a comparative Life-Cycle Assessment of the different treatment trains, similar assumptions were made in all cases for a hypothetical case study of a 50,000-PE reuse plant downstream of a secondary sewage treatment plant. All five proposed hybrid treatment trains are capable of supplying very high non-potable water quality, and the combination of disinfection, filtration and aquifer passage proved to be an efficient combination for removing suspended solids, residual BOD and microbiological contaminants. The environmental performance of the treatment trains was compared in terms of carbon footprint, but also energy demand, human toxicity, acidification impact and land footprint. Both the energy demand and carbon footprint of hybrid schemes was found to be considerably lower than for a double-membrane system, besides offering an additional storage solution in the aquifer. Thus, there is a significant margin for lowering the environmental impact, energy demand and operational costs if non-potable water quality is sufficient for the reuse goal. However, the legal context and social acceptability may represent barriers for this intended recharge of nonpotable water to the aquifer. This conceptual study has shown the potential of hybrid solutions to provide high-quality non potable water for aquifer recharge and further reuse. A large portfolio of solutions was proposed to reach the intended non-potable uses. To assist the selection of adequate treatment trains, the strengths and weaknesses of the solutions can be summarized in a decision tree taking into account the reuse goal, aquifer type and space availability, and selecting the least energy-intensive solution for a given legal and sociocultural context.

Managed Aquifer Recharge (MAR) is a means to replenish aquifers in case of over-abstraction and store water, especially in regions with semi-arid or arid climate. For water re-use schemes MAR can offer additional treatment in the subsurface so the CO2-footprint can be reduced. Pre-treatment via ozonation and dual media filtration before infiltration of treated wastewater was studied to compare the obtained water quality to guidelines for water reuse. While the removal of bulk parameters such suspended solids or chemical oxygen demand were easily reduced by ozonation and filtration, the disinfection turned out to be the limiting process.

Water is one of the sectors where climate change will be most pronounced. While the extents of the impacts are not known yet, it is the right period to prepare the utilities to adapt to the global changes in an urbanising world. Adaptation to climate change, though not always perceived as such, is often already reality in the urban water sector. Several adaptation strategies have been tested to address the key questions: Adapt to what? What to adapt? How to adapt? In this context, within the framework of the EU-project PREPARED, a tentative classification and catalogue of implemented initiatives in the water sector has been compiled. This catalogue is organised into four major categories of initiatives: (1) risk assessment and management, (2) supply-side measures, (3) demand-side measures and (4) global planning tools. The document aims at providing examples on how utilities could go ahead into preparing their water supply and sanitation systems to climate change. Initiatives include various measures ranging from the promotion of active learning to the prevention of sewer flooding and water conservation measures. Within PREPARED, this catalogue is supporting the development of solutions. Being a living document, it is updated regularly along the project when new solutions and initiatives are known. In addition, this work and the subsequent database of adaptation initiatives are accessible to a broader audience thanks to the web-based ‘WaterWiki’ of the International Water Association (IWA).

The optimisation of drinking water well field operation may significantly reduce the energy demand and associated costs, but is seldom applied in a systematic methodological approach. In this study, a well field was analysed using a coupled model that takes into account aquifer, wells, pumps and raw water pipes. This coupled approach enabled to identify and quantify the key energy demand drivers. The geometrical elevation was the most important driver, while pipe network losses were in the same order of magnitude as aquifer- and well losses. Using the modelling tool, the most energyefficient well field operation scheme could be derived and energy savings of up to 17% may be achieved by optimising well field operation only whereas further 5% may be saved by investing in new pump equipment. These findings show the potentials for significant energy savings in the field of drinking water abstraction.

Water is one of the sectors where climate change will be most pronounced, but at the same time it is one of the sectors where numerous adaptation possibilities exist. While the extents of the impacts are not known yet, it is the right period to prepare the utilities to adapt to the global changes in an urbanizing world. Adaptation to climate change, though not always perceived as such, is already reality in the urban water sector. In this context, within the framework of the international research project PREPARED funded by the European Commission and, among others, Veolia Water and local utilities, a toolbox consisting in a catalogue and a dynamic matrix of initiatives in the water sector is being compiled by the Berlin Centre of Competence for Water, KWB.