Comment on "Toxicological relevance of emerging contaminants for drinking water quality" by M. Schriks, M.B. Heringa, M.M.E. van der Kooi, P. de Voogt and A.P. van Wezel [Water Research 44 (2010) 461-476]

This is the post-print version of the final paper published in Water Research. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.No abstract available

Assessing the risks of recycling urban stormwater for potable supply via an aquifer

Urbanisation and the subsequent increase in impervious land use generate increased urban stormwater which can be recycled viamanaged aquifer recharge (MAR) to supplement more traditional surface or ground water supplies. This paper compares the quality of stormwater from two urban catchments in South Australia to assess the risks, in accordance with the Australian Guidelines for Water Recycling, of recycling stormwater via a limestone aquifer for potable water use. In the regional city of Mount Gambier, stormwater MARin a karstic aquifer has been used to supplement the city\u27s drinking water supply for over 100 years. The source water was generally high quality with some instances of turbidity, iron and lead exceeding the Australian Drinking Water Guidelines (ADWG). Effort wasmade to constrain the estimate of minimum residence time within the karstic aquifer to at least two years for evaluation of the potential for passive treatment of trace organic chemicals in this system. In the second example, a purpose built MAR site in Parafield, a northern suburb of Adelaide, has been designed and operated asa full scale trial to determine if wetland treated urban stormwater can be recovered at a standard which meets the ADWG. Based on the analysis undertaken, the source water was generally of high quality with occasional instances of levels of iron and microbial indicators in excess of the ADWG. After a mean residence time in the aquifer of 240 days, recovered water qualitymet the ADWGwith the exception of iron. However, given the uncertainty in pathogen concentrations in the treated stormwater post-recovery from the aquifer, disinfection and aeration for iron removal would be necessary to ensure that the ADWG were met if the water was to be utilised for potable water supply

Water Reuse in Europe - Relevant guidelines, needs for and barriers to innovation

An EU regulatory instrument for water reuse is planned to be developed by 2015, in order to find innovative solutions to the challenges of ensuring water supply for urban, industrial and agriculture use. Despite the water reuse applications already developed in many countries, a number of barriers still prevent the widespread implementation of water reuse around Europe and on a global scale. These barriers will have to be overcome. This JRC Science and Policy Report analyses the technical, environmental and socioeconomic challenges to the option of water reuse as a means of ensuring sufficient supply to meet the growing needs of society. It presents and compares the most relevant national and international guidelines on water reuse, evaluates existing water reuse standards in EU Member States, presents a risk-based management approach for wastewater reuse, and identifies the areas that require technological and regulatory innovation as well as the barriers to be overcome.JRC.H.1-Water Resource

Risk Assessment and Risk Management in Managed Aquifer Recharge and Recycled Water Reuse: The Case of Sabadell

[cat] La regeneració d’aigües és una pràctica cada cop més generalitzada, que pot incloure o no recàrrega artificial d’aqüífers (MAR: Managed Aquifer Recharge), i que requereix una avaluació dels riscs en sistemes reals en ús. L’estudi actual es desenvolupà a Sabadell, Espanya. En aquest cas de MAR la recàrrega de l’aqüífer es realitza a través del llit del riu Ripoll i s’utilitza l’efluent secundari d’una depuradora. L’aigua que posteriorment s’extreu de l’aqüífer passa per un tractament ultraviolat, cloració i filtre de sorra, i s’utilitza per al reg de parcs i neteja de carrers. Aquest sistema formà part del projecte europeu RECLAIM WATER. Al present treball s’ha desenvolupat una avaluació i gestió del risc. A més a més, s’ha fet un estudi del risc probabilístic, cosa habitual en aigües potables però no en aigües regenerades o en MAR. Les dades utilitzades per a l’avaluació del risc es van generar en el marc del projecte RECLAIM WATER. Altres dades es van obtenir d’institucions públiques i altres estudis. L’avaluació del risc per als usos considerats de l’aigua recuperada i tractada indica que aquest és baix i en alguns casos moderat, amb l’excepció de l’ús com a aigua potable, que no es preveu fer a Sabadell. Els riscs residuals que cal considerar i gestionar tenen com a protagonistes els compostos inorgànics, els compostos orgànics i la salinitat. Un altre resultat important a tenir en compte és que la recàrrega a través del llit del riu és un tractament efectiu per a reduir els riscs derivats de patògens, nutrients, compostos orgànics i partícules. Aquest resultat dóna suport a la demanda de molts autors de considerar el MAR com a un tractament més. Finalment, s’ha desenvolupat un pla de gestió del risc, integrant els resultats de l’avaluació del risc. En aquest pla no només s’han identificat els punts de control crític sinó que també s’han avaluat els dotze elements de les Guies Australianes per a la gestió del risc en MAR, fent molt més robust l’estudi. L’èmfasi ha estat posat en les accions correctives i preventives, la definició dels punts de control crític, la monitorització del sistema i els punts de mostreig.[eng] The increasing practice of water recycling, including or not managed aquifer recharge (MAR), requires to thoroughly assess the risks posed by it in real systems, not only in laboratory and column studies. The present work has been developed in a case study in Sabadell, Spain. For this site, the treated effluent of the Ripoll River WWTP is discharged into the Ripoll River, thus enhancing the natural infiltration to the alluvial aquifer. Pumping of the groundwater induces a riverbed filtration process (RBF), which is one of types of MAR. The recovered water undergoes further post-treatments, including UV, chlorination and sand filtration. After the post-treatments, the water is used for park irrigation and street cleaning. This site was part of the RECLAIM WATER project, supported by the European Commission and devoted to studying MAR and the use of reclaimed water for it in different locations in Europe, as well as in other countries outside Europe. For Sabadell case study, named “RISMAR” in the present work, a risk assessment and a risk management have been developed. In addition, a quantitative microbial risk assessment (QMRA) has been developed too. QMRA is not as usually applied to recycled water schemes as it is to drinking water ones, and even less to MAR. In order to develop the risk assessment, it was necessary to gather data on the site. Most of the data used to develop the present work were generated in the framework of the RECLAIM WATER project, and it included not only basic wastewater and surface water regular parameters and microbiological indicators, but also trace compounds, pathogens and antibiotic resistance genes. Other data were available from public institutions and previous works. The main results of the risk assessment indicate that for the uses considered for the final treated water the risk is low and in some cases medium, with the exception of using the final treated water as drinking water. Currently, this use it is not in place at the site, and it is not expected to be in the near future. The QMRA results additionally indicate that cross-connection, swimming and the immunocompromised population would be in the limit of the acceptable level of risk. Thus, the immunocompromised population should be considered in risk assessments, as the risk for them might be much higher than for the rest of the population. The residual risks that needed to be managed and considered were posed by inorganic compounds, organic compounds, salinity and mobilization of inorganic compounds from the sediments. Another important result of the work is that the RBF and subsurface treatment proved to be very useful in reducing the risks posed by pathogens, nutrients, organic compounds and particulates. In contraposition, other risks appeared, like the mobilization of inorganic compounds from the aquifer. Then, these positive results support the request by many authors of treating MAR as an additional treatment. Finally, a risk management plan has been developed, integrating the results of the risk assessment. For this risk management plan, not only the critical control points are identified, as it is typical for risk managements, but the twelve elements of the framework issued by the Australian Government (NRMMC-EPHC–NHMRC, 2009) have been assessed and developed, thus supporting a robust risk management plan. Emphasis is put in corrective and preventive actions for the system, as well as in defining the critical limits, monitoring program and sampling points. Besides, validation is given the importance it has in order to ensure a proper functioning of the system

Applying the water safety plan to water reuse: towards a conceptual risk management framework

The Water Safety Plan (WSP) is receiving increasing attention as a recommended risk management approach for water reuse through a range of research programmes, guidelines and standards. Numerous conceptual modifications of the approach – including the Sanitation Safety Plan, the Water Cycle Safety Plan, and even a dedicated Water Reuse Safety Plan – have been put forward for this purpose. However, these approaches have yet to encapsulate the full spectrum of possible water reuse applications, and evidence of their application to reuse remains limited. Through reviewing the existing evidence base, this paper investigates the potential for adapting the WSP into an approach for water reuse. The findings highlight a need for the management of risk to reflect on, and facilitate the inclusion of, broader contexts and objectives for water reuse schemes. We conclude that this could be addressed through a more integrated approach to risk management, encapsulated within an overarching risk management framework (adapted from the WHO's Framework for safe drinking water) and operationalised through the Water Reuse Safety Plan (WRSP). We also propose that the WRSP should be based on modifications to the existing WSP approach, including an increased emphasis on supporting communication and engagement, and improvements in decision support mechanisms to better account for uncertainty, risk interactions and risk prioritisation

From risk to safety management: stakeholder engagement to inform the governance and design if water reuse schemes.

Water reuse is a feasible technological approach to addressing urban water management challenges. Whilst stakeholder acceptance is acknowledged as important for scheme success, less is known about how to interpret and influence stakeholder attitudes to water reuse, how preferences for risk mitigation influence scheme design, and what forms of engagement with risk work in what contexts. This thesis aims to understand the nature of stakeholder perceptions and expectations in the context of water reuse schemes, and to critically evaluate how stakeholder engagement with risk management can be used to enhance the governance and design of water reuse schemes. Through an embedded case study design and mixed-methods research, perceptions of water reuse as a feasible water management intervention in London are explored. This study offers a number of contributions to the immediate field of research. Firstly, the findings highlight perceived benefits to engaging stakeholders through more collaborative learning-by-doing risk management. Secondly, the findings help to improve knowledge of methods for interpreting, informing and influencing stakeholders’ perceptions through mediums such as online news and video animations. Thirdly, findings contribute to the understanding of the effectiveness of communication through showing an impact on public perceptions predicated on the focal characteristics of risk management messages. Fourthly, findings indicate that preferences for different recycled water uses and perceptions of certain scheme configurations could influence design decisions. Finally, findings support benefits of including stakeholders in multi-criteria evaluations of risk-based decisions. A further contribution of this research is the identification of a number of thematic conditions necessary for enhancing scheme governance and design. These thematic conditions can assist in developing knowledge that focuses on overcoming the challenges of translating contemporary management and design theory into practice. In particular, this research highlights implication for advancing state-of-the-art risk management frameworks, specifically, through adopting more adaptive rationales informed through stakeholder engagement. This study contributes to the development of local and regional capabilities for water reuse risk management with implications for developing more strategic water reuse guidance and policy.STREAM EngD programm

Risk control in recycled water schemes

Recycled water is becoming one of the indispensable and reliable water resources at present. When it is introduced as an alternative source, risks on human health and the environment become major constraints driving the application and extension of recycled water. The authors examine the sources and associated risks of recycled water and introduce the practical risk control technologies on various end uses. They also review some existing risk assessment models by comparing their strengths and weaknesses toward the good approach of integrated modeling. Some critical suggestions on risk management and communication are made based on the given information. © 2013 Taylor and Francis Group, LLC

Quantitative microbial risk assessment of a non-membrane based indirect potable water reuse system using Bayesian networks

Indexación ScopusRisk-based approaches are used to define performance standards for water and wastewater treatment to meet health-based targets and to ensure safe and reliable water quality for desired end use. In this study, a screening level QMRA for a non-membrane based indirect potable reuse (IPR) system utilizing the sequential managed aquifer recharge technology (SMART) concept was conducted. Ambient removals of norovirus, Campylobacter and Cryptosporidium in advanced water treatment (AWT) steps were combined in a probabilistic QMRA utilizing Bayesian networks constructed in Netica. Results revealed that all pathogens complied with disease burden at the 95th percentile, and according to the assumptions taken about pathogen removal, Cryptosporidium was the pathogen with the greatest risk. Through systematic sensitivity analysis, targeted scenario analysis, and backwards inferencing, critical control points for each pathogen were determined, demonstrating the usefulness of Bayesian networks as a diagnostic tool in quantifying risk of water reuse treatment scenarios. © 2021 Elsevier B.V.https://www-sciencedirect-com.recursosbiblioteca.unab.cl/science/article/pii/S0048969721015308?via%3Dihu

Managed aquifer recharge at a farm level : evaluating the performance of direct well recharge structures

A field study evaluated the performance of direct well recharge structures (DWRS) in order to harvest and filter farm runoff and its discharge into open dug wells to augment groundwater recharge. This was undertaken between 2016 and 2018 using a total of 11 wells in the Dharta watershed, situated in a semi-arid hardrock region of Udaipur district, Rajasthan, India. The depth to water level in each DWRS well was monitored weekly for 1 to 3 years before and after the DWRS was established, and water samples were taken for water quality analysis (pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, fluoride, and Escherichia coli) before and during the monsoon period. For each DWRS well, two control wells in close proximity were also monitored and sampled. Five of the DWRS established in 2018 also had flow meters installed in order to measure discharge from the filter to the well. The volume of water recharged through DWRS into individual wells during the 2018 monsoon ranged from 2 to 176 m3 per well. Although the mean rise in water levels over the monsoon was higher in DWRS wells than in nearby control wells, the difference was not significant. Values of pH, EC, TDS, and F decreased in DWRS and control wells as each monsoon progressed, whereas the turbidity of wells with DWRS increased slightly. There was no significant difference between DWRS and control wells for pH, EC/TDS, turbidity, or fluoride. The presence of E. coli in DWRS wells was higher than in control wells, however, E. coli exceeded drinking water guidelines in all sampled wells. On the basis of this study, it is recommended that rural runoff should not be admitted to wells that are used for, or close to, wells used for drinking water supplies, even though salinity and fluoride concentrations may be reduced. For this study, none of the 11 DWRS wells produced sufficient additional recharge to potentially increase dry season irrigation supplies to justify expenditure on DWRS. This even applies to the DWRS well adjacent to a small ephemeral stream that had a significantly larger catchment area than those drawing on farmers’ fields alone. An important and unexpected finding of this study was that no sampled open dug well met drinking water standards. This has led to a shift in local priorities to implement well-head water quality protection measures for wells used for drinking water supplies. It is recommended that parapet walls be built around the perimeter of such dug wells, as well as having covers be installed