Characterization of unplanned water reuse in the EU. Final Report

In order to assess policy options regarding requirements for water reuse via agricultural irrigation and groundwater recharge, the European Commission requested an additional source of information. Thus, the aim of this study was to benchmark the current degree of unplanned water reuse in Europe, in particular in areas that are practicing agriculture irrigation and artificial groundwater recharge using surface water. This assessment included a characterization of qualities of water sources currently used in agricultural irrigation in the EU, including direct and indirect reuse of treated wastewater. In addition, the extent of unplanned reuse and the impact of the development of planned (and direct) water reuse has been assessed for case studies in selected EU river basins in Spain, Italy, France and GermanyCon el fin de evaluar las opciones políticas relativas a los requisitos de reutilización del agua a través del riego agrícola y la recarga de aguas subterráneas, la Comisión Europea solicitó una fuente adicional de información. Por lo tanto, el objetivo de este estudio era comparar el grado actual de reutilización no planificada del agua en Europa, en particular en las zonas que practican el riego agrícola y la recarga artificial de aguas subterráneas con aguas superficiales. Esta evaluación incluyó una caracterización de la calidad de las fuentes de agua utilizadas actualmente en el riego agrícola en la UE, incluida la reutilización directa e indirecta de las aguas residuales tratadas. Además, se ha evaluado el alcance de la reutilización no planificada y el impacto del desarrollo de la reutilización planificada (y directa) del agua para estudios de caso en cuencas hidrográficas seleccionadas de la UE en España, Italia, Francia y Alemania

Methodological Advances to Study Contaminant Biotransformation: New Prospects for Understanding and Reducing Environmental Persistence?

Complex microbial communities in environmental systems play a key role in the detoxification of chemical contaminants by transforming them into less active metabolites or by complete mineralization. Biotransformation, i.e., transformation by microbes, is well understood for a number of priority pollutants, but a similar level of understanding is lacking for many emerging contaminants encountered at low concentrations and in complex mixtures across natural and engineered systems. Any advanced approaches aiming to reduce environmental exposure to such contaminants (e.g., novel engineered biological water treatment systems, design of readily degradable chemicals, or improved regulatory assessment strategies to determine contaminant persistence a priori) will depend on understanding the causal links among contaminant removal, the key driving agents of biotransformation at low concentrations (i.e., relevant microbes and their metabolic activities), and how their presence and activity depend on environmental conditions. In this Perspective, we present the current understanding and recent methodological advances that can help to identify such links, even in complex environmental microbiomes and for contaminants present at low concentrations in complex chemical mixtures. We discuss the ensuing insights into contaminant biotransformation across varying environments and conditions and ask how much closer we have come to designing improved approaches to reducing environmental exposure to contaminants

Healthy living on a healthy planet - Summary

Unsere Lebensweise macht krank und zerstört die natürlichen Lebensgrundlagen. In der Vision „Gesund leben auf einer gesunden Erde“ werden menschliche Lebensbereiche – Ernähren, Bewegen, Wohnen – gesund und umweltverträglich gestaltet sowie planetare Risiken – Klimawandel, Biodiversitätsverlust, Verschmutzung – bewältigt. Gesundheitssysteme nutzen ihre transformativen Potenziale, Bildung und Wissenschaft befördern gesellschaftliche Veränderungen. Die Vision ist nur mit internationaler Kooperation realisierbar und erfordert eine globale Dringlichkeitsgovernance.Our lifestyle is making us ill and is destroying the natural life-support systems. In the vision of ‘healthy living on a healthy planet’, human spheres of life – what we eat, how we move, where we live – are designed to be both healthy and environmentally compatible, and planetary risks – climate change, biodiversity loss, pollution – have been overcome. Health systems harness their transformative potential; education and science promote societal change. The vision can only be realized with international cooperation and requires what the WBGU terms global urgency governance

Analysis of Greenhouse Gas Emissions in Centralized and Decentralized Water Reclamation with Resource Recovery Strategies in Leh Town, Ladakh, India, and Potential for Their Reduction in Context of the Water–Energy–Food Nexus

With the constant increase of population and urbanization worldwide, stress on water, energy, and food resources is growing. Climate change constitutes a source of vulnerability, raising the importance of implementing actions to mitigate it. Within this, the water and wastewater sector represents an important source of greenhouse gas (GHG) emissions, during both the construction and operation phase. The scope of this study is to analyze the GHG emissions from the current and future water supply scheme, as well as to draw a comparison between possible water reclamation with resource recovery scenarios in the town Leh in India: a centralized scheme, a partly centralized combined with a decentralized scheme, and a household level approach. Precise values of emission factors, based on the IPCC Guidelines for National Greenhouse Gas Inventories, previous studies, and Ecoinvent database, have been adopted to quantify the different emissions. Potential sources of reduction of GHG emissions through sludge and biogas utilization have been identified and quantified to seize their ability to mitigate the carbon footprint of the water and wastewater sector. The results show that the future water supply scheme will lead to a significant increase of the GHG emissions during its operation. Further, it is shown that decentralizing wastewater management in Leh town has the least carbon footprint during both construction and operation phases. These results have implications for cities worldwide

Reducing the Impacts of Biofouling in RO Membrane Systems through In Situ Low Fluence Irradiation Employing UVC-LEDs

Biofouling is a major concern for numerous reverse osmosis membrane systems. UV pretreatment of the feed stream showed promising results but is still not an established technology as it does not maintain a residual effect. By conducting accelerated biofouling experiments in this study, it was investigated whether low fluence UV in situ treatment of the feed using UVC light-emitting diodes (UVC-LEDs) has a lasting effect on the biofilm. The application of UVC-LEDs for biofouling control is a novel hybrid technology that has not been investigated, yet. It could be shown that a low fluence of 2 mJ∙cm−2 delays biofilm formation by more than 15% in lab-scale experiments. In addition, biofilms at the same feed channel pressure drop exhibited a more than 40% reduced hydraulic resistance. The delay is probably linked to the inactivation of cells in the feed stream, modified adsorption properties or an induced cell cycle arrest. The altered hydraulic resistance might be caused by a change in the microbial community, as well as reduced adenosine triphosphate levels per cells, possibly impacting quorum sensing and extracellular polymeric substances production. Due to the observed biofilm attributes, low fluence UV-LED in situ treatment of the feed stream seems to be a promising technology for biofouling control

A novel concept to integrate energy recovery into potable water reuse treatment schemes

Potable water reuse applications can provide a safe and sustainable water supply where conventional freshwater resources are limited. The objectives of this study were fourfold: (i) to analyse existing potable water reuse applications regarding operational characteristics and energy demands, (ii) to determine the theoretical energy potential of wastewater and identify opportunities for energy recovery, (iii) to define design requirements for potable water reuse schemes that integrate energy recovery and (iv) to propose strategies for more energy efficient potable water reuse schemes. Existing potable water reuse schemes commonly utilize conventional wastewater treatment processes including biological nutrient removal followed by advanced water treatment processes. While meeting high product water quality, these treatment schemes are characterized by relatively high specific energy demands (1.18 kWh/m3). Given that the theoretical energy potential of municipal wastewater is approximately two times higher (2.52 kWh/m3), opportunities exist to integrate energy recovery strategies. We propose three alternative potable water reuse schemes that integrate energy recovery from carbon via methane and nitrogen via either the coupled aerobic–anoxic nitrous decomposition operation process or partial nitritation/anammox. Compared to conventional potable water reuse schemes, the energy requirements of these schemes can be reduced by 7–29% and the overall energy balance by 38–80%

Strategies for enhanced deammonification performance and reduced nitrous oxide emissions

Deammonification's performance and associated nitrous oxide emissions (NO) depend on operational conditions. While studies have investigated factors for high performances and low emissions separately, this study investigated optimizing deammonification performance while simultaneously reducing NO emissions. Using a design of experiment (DoE) method, two models were developed for the prediction of the nitrogen removal rate and NO emissions during single-stage deammonification considering three operational factors (i.e., pH value, feeding and aeration strategy). The emission factor varied between 0.7±0.5% and 4.1±1.2% at different DoE-conditions. The nitrogen removal rate was predicted to be maximized at settings of pH 7.46, intermittent feeding and aeration. Conversely, emissions were predicted to be minimized at the design edges at pH 7.80, single feeding, and continuous aeration. Results suggested a weak positive correlation between the nitrogen removal rate and NO emissions, thus, a single optimizing operational set-point for maximized performance and minimized emissions did not exist

Application of the Water–Energy–Food Nexus Approach to the Climate-Resilient Water Safety Plan of Leh Town, India

Climate-resilient water safety plans (CR-WSPs) have been developed as a risk-based approach to ensure a safe drinking-water supply while addressing the increasing stress on water resources resulting from climate change. Current examples of the application of CR-WSPs show a strong sectoral approach that fails to explore the potential synergies between other climate-sensitive sectors related to water, such as food and energy. This can increase the vulnerability or decrease the overall resilience of urban systems when planning climate change adaptation measures. In this work, the Water–Energy–Food (WEF) Nexus approach was applied in the formulation of a CR-WSP in Leh Town, India, a city with rapid development and population growth located in the Himalayas—one of the most sensitive ecosystems to climate change. The WEF Nexus approach was applied in the system description using a critical infrastructure approach and in the formulation of scenarios for risk management which exploited intersectoral synergies through water reclamation with resource recovery using constructed wetlands. The improvements in WEF security and risk reduction were demonstrated through indicators and risk mapping with geographical information systems (GISs). The methods for integrating the WEF Nexus approach in CR-WSPs provided through this work can serve as a base for a trans-sectoral, resilient approach within risk-based approaches for water security

Neighborhood-Scale Urban Water Reclamation with Integrated Resource Recovery for Establishing Nexus City in Munich, Germany: Pipe Dream or Reality?

With the rapid expansion of cities due to population growth and urbanization, conventional centralized wastewater collection and treatment systems are slowly becoming a burden; expensive maintenance is required for aging plants and piping infrastructure, the cost of expanding the capacity to cover demand from population growth, and new regulations for tighter control over certain pollutants such as micropollutants. As an alternative to this system, this study discusses the feasibility of decentralized treatment systems at the neighborhood scale. Taking a Water-Energy-Food (WEF) Nexus approach, such systems can support water and energy conservation, recovery of water, energy, and nutrients as well as generation of energy from wastewater, be customized to individual water and energy requirements, and eliminate the need for lengthy pipe networks. The method employed in this study is comparing the economic feasibility of the status quo to a proposed decentralized solution. The study finds that the costs of implementing a hypothetical decentralized water reclamation with an integrated resource recovery system using an anaerobic membrane bioreactor (AnMBR) in a downtown high-density neighborhood of the city of Munich, Germany, can theoretically be recuperated within two years. This alternative system may cost 60% of what it costs to run the centralized system. By linking the AnMBR to a biogas digestor and using systematically harvested organic waste as a co-substrate, the decentralized system can generate enough energy to run itself and even feed some energy to the grid. This study is highly hypothetical, yet generating evidence such as this can support a systemic socio-technical transition towards a more circular economy with optimal resource recovery