In recent decades, emerging contaminants (ECs) have surfaced as one of the key environmental problems threatening ecosystems and public health. Most emerging contaminants are present in low concentrations, and therefore often remain undetected and are also referred to as ‘micropollutants’. Despite this, many ECs raise considerable concerns regarding their impacts on human and environmental health. DEMEAU (Demonstration of promising technologies to address emerging contaminants in water and wastewater), a European Seventh Framework Programme (EU-FP7, 2013-2015) project, aimed to tackle ECs in drinking and wastewater by advancing the uptake of knowledge, prototypes, practices and removal technologies. The project followed a solutions-oriented approach using applied research and demonstration sites, and explored four promising technologies for EC removal and/or degradation: Managed Aquifer Recharge (MAR), Hybrid Ceramic Membrane Filtration (HCMF), Automatic Neural Net Control Systems (ANCS) and Advanced Oxidation Techniques (AOT). Furthermore, Bioassays (BA) were investigated as an effect-based monitoring tool. This article shares new findings for each approach and their potential for widespread integration in the drinking- and wastewater sector. Research results from DEMEAU demonstration sites show that opportunities for synergies among these developments offer the most promising and effective methods for tackling ECs in the water sector.

Different types of managed aquifer recharge (MAR) schemes are widely distributed and applied on various scales and for various purposes in the European countries, but a systematic categorization and compilation of data has been missing up to now. The European MAR catalogue presented herein contains various key parameters collected from the available literature. The catalogue includes 224 currently active MAR sites found in 23 European countries. Large quantities of drinking water are produced by MAR sites in Hungary, Slovakia, the Netherlands, Germany, Finland, Poland, Switzerland and France. This inventory highlights that, for over a century, MAR has played an important role in the development of European water supply and contributes to drinking-water production substantially. This development has occurred autonomously, with “trial-and-error” within the full range of climatically and hydrogeologically diverse conditions of the European countries. For the future, MAR has the potential to facilitate optimal (re)use and storage of available water resources and to take advantage of the natural purification and low energy requirements during MAR operations. Particularly with respect to the re-use of wastewater treatment-plant effluent and stormwater, which is currently underdeveloped, the use of MAR can support the public acceptance of such water-resource efficient schemes. Particularly for the highly productive and urbanized coastal zones, where the pressure on freshwater supplies increases by growing water demand, salinization and increased agricultural needs for food production (such as along the Mediterranean and North Sea coasts), MAR is expected to be increasingly relied on in Europe.

The La Vall d’Uixó (Spain) pilot site has been selected by DEMEAU because it is a new Aquifer Storage Transfer and Recovery (ASTR) site consisting of two injection wells surrounded by farmer wells for irrigation in a water scarce area. Potential water source for this MAR site is the effluent of the local WWTP, which is a quite constant water source in terms of availability, but gives concerns in terms of water quality. The investigations carried out within DEMEAU supports the work previously done by the Water Recovery Project (2011 – 2014), coordinated by IGME (Instituto Geológico y Minero de España) and UJI (Universitat Jaume I). The Water Recovery Project consists of different implementation phases and aimed to establish an appropriate MAR scheme with reclaimed wastewater to counteract salinity ingress in the coastal aquifer. In the third phase of the project two injection wells have recharged 310,000 m3 with water from the Belcaire River. To foster the implementation of the fourth and final phase of the Water Recovery Project, DEMEAU focused on the evaluation of the effluent of the local WWTP as source water for the ASTR system. This has been done by three sampling campaigns to analyse bulk chemistry, emerging pollutants and bioassays in native groundwater (six agricultural wells), Belcaire River (the current source water of the MAR scheme) and WWTP effluent (potential future source water). Risk assessment based on Australian MAR guidelines have been applied to evaluate risks related to the usage of WWTP effluent as source water. The Australian guidelines have been applied in two steps: entry level assessment and maximal risk assessment. Entry level assessment concluded that La Vall d’Uixó is suitable for a MAR scheme using reclaimed water, while maximal risk assessment identified hazards associated to reclaimed water as source water. As La Vall d’Uixó is an agricultural area of citrus crops, the use of reclaimed water for the injection in the MAR system must be compatible with the use of recovered water for irrigation. The risk assessment done in this report considered this end use of water, as there are no drinking water wells in the area. High risks have been identified for inorganic chemicals (conductivity, chloride and bicarbonate) and nutrients (nitrate). Risks associated to inorganics can be minimized by mixing effluent and Belcaire River water 1:1. Bulk chemistry coincided mainly with the description carried out in Water Recovery project, identifying two main quality problems in native groundwater: (1) salinity ingress (2) high nitrate concentration due to the intensive agricultural practices in the area. Ion displacement pattern in groundwater samples clearly indicates on-going salinization and documents minor effects of the injected water on few wells only. Cl/Br ratios indicate additional sources of chloride apart from seawater. It seems plausible that the underlying Keuper formations (Triassic) contribute to salinity ingress and SO4 excess in groundwater to some extent. Chlorides and nitrate are regulated by the implementation in Spain of the EU Water Framework Directive for the Castellón aquifer. The threshold value for nitrate is 200 mg/L, while the threshold value for chloride is 650 mg/L. WWTP effluent has nitrate and chlorides below the threshold concentrations (60 mg/L and 140 mg/L respectively) and, therefore, the MAR with reclaimed water would suppose a reduction of groundwater pollution and a step towards a qualitative good status in the aquifer. In total 63 organic micro pollutants have been analysed in groundwater, surface water and WWTP effluent. WWTP effluent shows elevated concentrations in almost all groups of organic micro pollutants compared to river- or groundwater. Only pesticides are found in higher concentrations in groundwater compared to the effluent. The Belcaire River shows the lowest concentrations for all groups of micro pollutants. It was shown that the Vall d’Uixó aquifer is contaminated by various organic micro pollutants and does not reflect a near natural aquifer condition. The aquifer chemistry in terms of organic micro pollutants reflects the usage of (untreated) effluent for direct irrigation over years. Elevated concentration of artificial sweeteners, analgesics, stimulants, caffeine metabolites and cocaine metabolites were found in WWTP samples taken during weekends compared to workday samples. In contrast, iopromide has been quantified in higher concentrations in the effluent of WWTP in work days than in the weekend, as this contrast media is used in hospitals for diagnostic tests normally carried out from Monday to Friday. These patterns of the effluent of WWTP during the week of weekend could be determinant for the selection of the working days as most suitable days to store treated waste water. In order to link analysed chemical concentrations to the observed toxicity in the samples a procedure based on bioassay-specific relative potency (REP) factors was applied. REP factors are determined by the effect concentrations of the reference compound and of the test compound. Despite the lack of toxicological data for a number of the selected target compounds and the lower relevance of the selected compounds for (eco)toxicological risk assessment, this study greatly demonstrate the usefulness of combined analyses of environmental samples. Effect-based methods could complement conventional chemical analysis in water quality monitoring as pre-screening techniques by (1) identifying toxic “hotspots” for further investigation, (2) assessing the effect of the entire mixture of compounds present in waters and therefore and (3) reduce uncertainty in safety evaluation.

This project report summarizes work conducted in work package 11. Along with the deliverable 11.1 and milestone report 11 it covers the tasks from work package 11 as formulated in the Description of Work (DoW). The content of the different sections is interrelated, but each section is organized as an independent part. Title of this report differs from DoW because recommendations for optimum design and operation will be handled in the deliverable 12.2. The sections in this report cover various topics and each section can be found as a stand-alone report in the DEMEAU tool box (http://demeaufp7.eu/toolbox/) for download. Detailed summaries can be found for each section separately.

The La Vall d’Uixó (Spain) pilot site has been selected by DEMEAU because it is a new Aquifer Storage Transfer and Recovery (ASTR) site consisting of two injection wells surrounded by farmer wells for irrigation in a water scarce area. Potential water source for this MAR site is the effluent of the local WWTP, which is a quite constant water source in terms of availability, but gives concerns in terms of water quality. The investigations carried out within DEMEAU supports the work previously done by the Water Recovery Project (2011 – 2014), coordinated by IGME (Instituto Geológico y Minero de España) and UJI (Universitat Jaume I). The Water Recovery Project consists of different implementation phases and aimed to establish an appropriate MAR scheme with reclaimed wastewater to counteract salinity ingress in the coastal aquifer. In the third phase of the project two injection wells have recharged 310,000 m3 with water from the Belcaire River. To foster the implementation of the fourth and final phase of the Water Recovery Project, DEMEAU focused on the evaluation of the effluent of the local WWTP as source water for the ASTR system. This has been done by three sampling campaigns to analyse bulk chemistry, emerging pollutants and bioassays in native groundwater (six agricultural wells), Belcaire River (the current source water of the MAR scheme) and WWTP effluent (potential future source water). Risk assessment based on Australian MAR guidelines have been applied to evaluate risks related to the usage of WWTP effluent as source water. The Australian guidelines have been applied in two steps: entry level assessment and maximal risk assessment. Entry level assessment concluded that La Vall d’Uixó is suitable for a MAR scheme using reclaimed water, while maximal risk assessment identified hazards associated to reclaimed water as source water. As La Vall d’Uixó is an agricultural area of citrus crops, the use of reclaimed water for the injection in the MAR system must be compatible with the use of recovered water for irrigation. The risk assessment done in this report considered this end use of water, as there are no drinking water wells in the area. High risks have been identified for inorganic chemicals (conductivity, chloride and bicarbonate) and nutrients (nitrate). Risks associated to inorganics can be minimized by mixing effluent and Belcaire River water 1:1. Bulk chemistry coincided mainly with the description carried out in Water Recovery project, identifying two main quality problems in native groundwater: (1) salinity ingress (2) high nitrate concentration due to the intensive agricultural practices in the area. Ion displacement pattern in groundwater samples clearly indicates on-going salinization and documents minor effects of the injected water on few wells only. Cl/Br ratios indicate additional sources of chloride apart from seawater. It seems plausible that the underlying Keuper formations (Triassic) contribute to salinity ingress and SO4 excess in groundwater to some extent. Chlorides and nitrate are regulated by the implementation in Spain of the EU Water Framework Directive for the Castellón aquifer. The threshold value for nitrate is 200 mg/L, while the threshold value for chloride is 650 mg/L. WWTP effluent has nitrate and chlorides below the threshold concentrations (60 mg/L and 140 mg/L respectively) and, therefore, the MAR with reclaimed water would suppose a reduction of groundwater pollution and a step towards a qualitative good status in the aquifer. In total 63 organic micro pollutants have been analysed in groundwater, surface water and WWTP effluent. WWTP effluent shows elevated concentrations in almost all groups of organic micro pollutants compared to river- or groundwater. Only pesticides are found in higher concentrations in groundwater compared to the effluent. The Belcaire River shows the lowest concentrations for all groups of micro pollutants. It was shown that the Vall d’Uixó aquifer is contaminated by various organic micro pollutants and does not reflect a near natural aquifer condition. The aquifer chemistry in terms of organic micro pollutants reflects the usage of (untreated) effluent for direct irrigation over years. Elevated concentration of artificial sweeteners, analgesics, stimulants, caffeine metabolites and cocaine metabolites were found in WWTP samples taken during weekends compared to workday samples. In contrast, iopromide has been quantified in higher concentrations in the effluent of WWTP in work days than in the weekend, as this contrast media is used in hospitals for diagnostic tests normally carried out from Monday to Friday. These patterns of the effluent of WWTP during the week of weekend could be determinant for the selection of the working days as most suitable days to store treated waste water. In order to link analysed chemical concentrations to the observed toxicity in the samples a procedure based on bioassay-specific relative potency (REP) factors was applied. REP factors are determined by the effect concentrations of the reference compound and of the test compound. Despite the lack of toxicological data for a number of the selected target compounds and the lower relevance of the selected compounds for (eco)toxicological risk assessment, this study greatly demonstrate the usefulness of combined analyses of environmental samples. Effect-based methods could complement conventional chemical analysis in water quality monitoring as pre-screening techniques by (1) identifying toxic “hotspots” for further investigation, (2) assessing the effect of the entire mixture of compounds present in waters and therefore and (3) reduce uncertainty in safety evaluation.