The overall aim of the CWPharma project is to reduce the load of active pharmaceutical ingredients (APIs) going into the aquatic environment and especially the Baltic Sea. Municipal wastewater treatment plants (WWTPs) are relevant point sources of APIs, as they treat the wastewater from public households, hospitals and industry of the connected catchment area. However, conventional "state-of-the-art" WWTPs can only remove some APIs, which are either easily biodegradable and/or absorbable to activated sludge, whereas other APIs can pass the WWTP with minor to no reduction. Therefore, reduction of a broad range of APIs can only be achieved by using targeted advanced treatment techniques such as ozonation or powdered and granular activated carbon, respectively, which have already been applied on full-scale for API removal in wastewater treatment in Germany and Switzerland and proven their practical and economical suitability. At the usual applied ozone doses, ozonation of secondary effluent does not mineralize (convert an organic substance into inorganic matter) but transforms organic compounds into smaller and (usually) more biodegradable compounds. Secondary effluent is a complex water matrix consisting of hundreds of different organic substances, and it is not feasible to determine all possible transformation products and oxidation by-products, which might be created by the ozonation process. Thus, utilities and water authorities sometimes struggle with the uncertainties of the ozonation process as they perceive difficulties to judge whether oxidation of the organic matrix is beneficial or if it is creating more problems. As chemical analysis of the water only provides quantitative data for known APIs and transformation products for which chemical standards are available, effect-based ecotoxicological test systems can be used to assess the integrated actual toxicity of the whole water matrix. Based on previous research compiled by Völker et al. (2019), ozonation has a positive impact on several toxicological endpoints. But there are also indications that ozonation can create negative effects for a few toxicological endpoints that can be reduced by a suitable post-treatment. However, only little knowledge is available regarding suitable post-treatments and which ecotoxicological test systems are appropriate to evaluate their impact. In addition, post-treatment options might also have beneficial impacts on water quality parameters, APIs and transformation products. Thus, this report will evaluate different aspects regarding the impact of ozonation and its posttreatment options on (i) water quality parameters, (ii) APIs and transformation products (TPs) and (iii) ecotoxicological effects. The evaluation was conducted at three WWTPs in Linköping (SE), Kalundborg (DK) and Berlin (DE) and different post-treatment options such as moving bed bioreactors (MBBR), deep-bed filters, and a constructed wetland.

The final report of the project COSMA describes the modeling results of four different scenarios regarding the pressure build-up in shallow aquifers due to the injection of CO2 into the sandstone aquifers of the Detfurth Formation. It is based on the “Technical Report on hydrogeological and static structural geological model implementation” (D 2.1) which focuses on the compilation of geological and hydrogeological background data (average values) and the development of a simplified conceptual hydrogeological model for a setting typical for the Northern German Sedimentary Basin as well as the model selection, model parameterization, definition of boundary conditions and implementation in hydrogeological flow model software packages. The hydrogeological model of the Cenozoic includes Quaternary and Tertiary aquifers down to the layer beneath the Rupelian clay. Moreover, a concept for modeling the interaction between deep, consolidated, saline aquifers with unconsolidated freshwater aquifers was developed. This report describes scenario analyses by using the numerical hydraulic model of the Detfurth Formation (Middle Bunter) and the simplified numerical groundwater model of the Cenozoic. The numerical models can be used to assess the key parameters, having an impact on the upconing of deeper saline groundwater beneath the well fields of water works (in shallow aquifer) due to imposed pressure signals.

In Chennai (India) public water supply and agriculture depend on groundwater to various extents, but the valuable resource shows increasing salinity over the past decades due to seawater intrusion. This study aims at identifying major hydrogeological processes which lead to salinity ingress in the main aquifer and investigates the effect of MAR structures such as check dams. Regional hydrochemistry is discussed by a combination of stiff diagrams, Cl/Br ratios, ion exchange diagram and stable isotopes (d18O, dD). The identified hydrogeochemical processes were high saline evolution due to intensive seawater evaporation for commercial salt production and typical ion displacement under refreshening and salinization conditions. Stable isotopes give new insights on (1) mixing processes of different end members (2) occurrence and degree of evaporation in ground- and surface water and (3) isotopical characterisation of groundwater recharge of the region. The identified processes were summarized in a conceptual model of the region. © 2014 Springer-Verlag Berlin Heidelberg.

Increasing subsurface activities like geothermal energy production, unconventional gas exploitation (EGR – enhanced gas recovery), enhanced oil recovery (EOR) or geological carbon dioxide storage (GCS) are potentially hazardous for the environment. Especially fresh water aquifers used as drinking water resources need to be protected. The first phase of the project COSMA focuses on potential hazards and hazardous events arising from those activities and aims at developing an approach for quantifying and comparing potential risks. A general description of hazards and hazardous events resulting from emerging subsurface activities is given in the first deliverable D1.1 “Geological CO2 Storage and Other Emerging Subsurface Activities: Catalogue of Potential Impacts on Drinking Water Production”. In this 2nd deliverable, reported hazards and hazardous events resulting from geothermal energy production in Germany are described. This report includes analyses of enquiries to experts from all federal states, State Geological Surveys, information from standardization committees, developers, planners, drilling contractors, expert committees, consulting engineers and regulatory authorities such as environmental agencies, water authorities and mining authorities as well as from media reports. It aims to list and categorize observed impacts arising from recent geothermal projects, as there have been increasing activities in this field in the past 10 years in Germany and because there are many similarities to other subsurface activities with respect to drilling processes, fracking methods and reinjection of fluids. The German classification of geothermal systems distinguishes between shallow or nearsurface (< 400 m depth) and deep geothermal energy (> 400 m depth) systems, which will be used in the following chapters. Table 1 shows the difference to international classification schemes, regarding enthalpies and temperatures. The reported case studies of failures potentially leading to contamination of freshwater aquifers are described in chapter 2 with respect to the setting and the reason for failure (if known). Chapter 3 gives some recommendations with respect to possible precautions and countermeasures to prevent such potentially hazardous events. Regardless of the drilling depth there are general hazards and hazardous events that must be taken into account for all subsurface activities. Amongst these are hazardous events during operation which can lead to a contamination of the site, hazardous events during drilling caused by wrongly selected drilling techniques, drilling into unknown caverns, cavities or caves or faulty casing, construction or plugging (sealing). Furthermore, unexpected chemical reactions between fluids and casing or sealing material (e.g. grout) can cause seepage or leakage and therefore hydraulic short circuits. Table 2 gives a summary of general impacts of drilling, especially when multiple aquifers are intersected, as well as from operation of geothermal facilities. Further details are given in COSMA-1 report D 1.1.

The overall goal of the project Cosma-1: “Geological CO2 storage and other emerging subsurface activities” is the assessment of potential impacts of subsurface activities on shallow aquifers used for drinking water production. The first two deliverables (D 1.1 and D 1.2) dealt with general approaches for risk assessment and a description of potential hazards and hazardous events, which might be a risk for shallow freshwater aquifers, as well as lessons learned from existing geothermal energy production and storage sites in Germany. This Technical Report describes the activities of the second phase of the project COSMA-1 and focuses on the compilation of geological and hydrogeological background data (average values) and the development of a simplified conceptual hydrogeological model for a setting typical for the Northern German Sedimentary Basin. The hydrogeological model of the Cenozoic includes Quaternary and Tertiary aquifers down to the layer beneath the Rupelian clay. On this basis, a numerical model with the program Modflow (PMWIN 5.3) was implemented as no complex geometries had to be considered. The structural geological model of the target formation for underground utilisation, the Detfurth Formation (Middle Bunter), incorporates four different fault systems with nine faults in total enclosing the area of interest. Further, a concept for modeling the interaction between deep, consolidated, saline aquifers with unconsolidated freshwater aquifers in a setting typical for the Northern German Sedimentary Basin was developed. This included the model selection, model parameterization, definition of boundary conditions and implementation in hydrogeological flow model software packages. In the further course of the project, a scenario analysis will be performed by using the numerical hydraulic model of the Middle Bunter and the simplified numerical groundwater model of the Cenozoic. The numerical models will be used to assess the key parameters, having an impact on the upconing of deeper saline groundwater beneath the well fields of water works (in shallow aquifer) due to imposed pressure signals.