Assessment of water, sanitation, and hygiene services in district health care facilities in rural area of Mekong Delta, Vietnam

Access to sufficient water, sanitation, and hygiene (WASH) services is a crucial requirement for patients during therapy and general well-being in the hospital. However, in low- and middle-income countries, these services are often inadequate, resulting in increased morbidity and mortality of patients. This study aimed at assessing the current situation of WASH services in six District Health Care Facilities (DHCFs) in rural areas of the Mekong Delta provinces, Vietnam. The results showed that these services were available with inappropriate quality, which did not compromise the stakeholders' needs. The revealed WASH infrastructures have raised concerns about the prolonged hospital stays for patients and push nosocomial infections to a high level. The safety of the water supply was doubted as the high E. coli (> 60%) and total coliform incidence (86%) was observed with very low residual chlorine concentration (

Water use and quality in life cycle assessment

Anna Kounina

Pressure on freshwater resources is increasingly covered by methodological developments addressing freshwater use in the field of Life Cycle Assessment (LCA). These developments ultimately lead to the publication of the ISO 14046 standard to define the principles, requirement and guidelines for a water footprint in August 2014. The objective of this thesis is to foster the application of water footprint by identifying good practices and developing operational approaches to assess and improve its discriminatory power. Indeed, academic development and LCA application by practitioners often evolve within distinct communities and with various practical constraints. For instance, newly developed methods are spatially differentiated to reduce model uncertainty, improve accuracy, precision and confidence in LCA results. However, models officially recommended by the European commission for product water footprints are generic (i.e., results do not depend on location), such as USEtox for the modelling of the human toxic and ecotoxic impacts. The trade-off between theoretical variability reduction and decrease of uncertainty in practice considering the level of geographical information available to the practitioner requires solutions meeting the needs of both LCA actors. This thesis answers the need to bridge methodological development and water footprint application through three main specific objectives: - Review existing and applicable inventory and impact assessment methods that address quantitative freshwater use in a life cycle perspective and provide preliminary application recommendations for practitioners - Analyse spatial differentiation of toxic emissions to water applied to USEtox at the inter-continental and intra-continental level and explore simplified spatial differentiation approaches such as spatial archetypes - Develop a fate and exposure characterization model and factors for toxic emissions into water with global coverage and fine resolution and test practical solutions to apply spatial characterization factors on a case study The first part of this thesis (Chapter 2) focuses on quantitative aspects of water use by providing a comprehensive review of existing and applicable inventory and impact assessment methods that address freshwater use. This analysis proves that a water footprint is already applicable for experienced practitioners relying on the current state-of-the-art methods. It provides a basis to reference the state-of-the-art of methods addressing water use in LCA already used and cited by several authors in the field of water management and specific water footprint case studies. Practical solutions to operationalize spatial differentiation are tested in Chapter 3 and 4, focusing on impact pathways generated by toxic emissions into water. Spatially differentiated landscapes and models are first developed as a reference to test simplified approaches: (1) landscape parameters are created for USEtox to develop continent and sub-continent specific boxes nested within the world and (2) a fate and exposure characterization model and factors are developed to assess toxic emissions into water with global coverage at 0.5°*0.5° resolution. The results of this work prove that using a generic model is acceptable to cover a low resolution such a continent, country, or sector when the detailed emission location is unknown while a finer resolution is essential for a regional impact score at the watershed or point source level.

EPFL2014

Inactivation of waterborne viruses by ozone: Kinetics and mechanisms

Camille Wolf

The growing world population, in conjunction with climate change, cases the global water de-mand to increase. It is, therefore, crucial to protect existing water resources from chemical pollution and contamination by pathogens. An increasingly popular strategy to meet increased water demand is pota-ble water reuse, which uses wastewater effluent as the water source and treats it to such an extent that it is safe to drink. However, this practise may encompass risks for human health if the treatment train does not ensure a sufficient removal of chemical and microbial contaminants. In the context of both wa-ter and wastewater treatment, ozonation has emerged as an efficient treatment method for the control of pathogens, the abatement of organic micropollutants, and the removal of taste and odor compounds. Despite its popularity, information on the inactivation of waterborne viruses by ozone is scarce. The aim of this thesis was to investigate the kinetics and mechanisms of inactivation of water-borne viruses by ozone. In a first step, the inactivation kinetics of a suite of human viruses and commonly used surrogates (bacteriophages) were determined in well-controlled buffer systems. To this end, we developed a method to control O3 decay in batch reactors. This allowed us to measure virus inactivation as a function of low ozone exposures. The resulting inactivation rate constant (kO3-virus) differed between the virus species studied, but all kO3-virus fell within a narrow range of 105-106 M-1s-1. These high inactivation rate constant indicate that ozone is efficient to inactivate waterborne virus. Increases in temperature and pH resulted in an increased kO3-virus, though the effect was relatively minor. To determine if more complex, natural water matrices influence virus inactivation by ozone, we investigated the virucidal efficacy of ozone in two surface waters and a secondary wastewater effluent. While inactivation kinetics as a function of ozone exposure initially corresponded well to those observed in buffer solutions, the inactivation curve tailed off at higher ozone exposures. Furthermore, because it is not possible to measure virus inactivation during water treatment in real-time, we tested different if âeasy-to-measureâ proxies can be used to track virus inactivation. We determined that the applied specif-ic ozone dose, the reduction in UV254, or the abatement of carbamazepine all correlated to virus inactiva-tion, though some proxy-inactivation relationships were not universal but depended on the water type. The proxies were validated in a pilot-scale ozonation reactor treating Lake Zurich water, and were found to provide good estimates of virus inactivation. Finally, an immunostaining assay was developed to observe how ozonation affects crucial steps in the life cycle of echovirus 11, a representative of the Enterovirus genus. Specifically, we investigated if ozone alters the ability of the virus to enter the host cells, and if it prevents the viral genome from replicating. Preliminary results indicate a loss of internalization after ozone treatment as well as genome replication. In conclusion, this thesis provides new information on the efficacy and mechanisms of ozone as an inacti-vating treatment for waterborne viruses, and it delivers tools to monitor virus inactivation during water and wastewater treatment in real-time.

EPFL2019

Swiss Potential for Hydropower Generation and Storage - Synthesis report

François Avellan, Paolo Burlando, Pedro Filipe De Almeida Manso, David Felix, Martin Schmid

Hydropower (HP) is the backbone of the Swiss electricity system providing around 60 % (36 TWh/a) of the total electricity generated on a yearly average. With the planned phase-out of nuclear power plants, HP and other Renewable Energy Sources (RES) will need to fill the substantial gap in domestic electricity generation, particularly in the winter season. Because of the intermittent nature of RES generation (mainly solar photovoltaics and wind) and their typically lower production in winter, the need for storage up to the seasonal time scale increases. Such large-scale storage is offered mainly by storage HP. However, maintaining the HP infrastructure will pose significant challenges, mainly due to market and legal conditions. For the latter, partly diverging interests according to the Swiss legislation will need to be fulfilled at the same time. On the one hand, HP is supposed to be extended in the scope of the Energy Strategy (ES) 2050 and to keep climate goals by reducing greenhouse gas emissions. On the other hand, current negative effects of mainly older HP infrastructure on aquatic ecology will need to be remediated according to the Swiss Waters Protection Act to fulfill biodiversity goals. Meeting all these goals will require to systematically refurbish the existing Swiss HP fleet, to extend it in a smart way with prioritization on large storage HP to foster electricity generation in the critical winter season and to construct new HP schemes, again with a focus on electricity generation in winter. As to new HP facilities, the retreating glaciers open new opportunities for high-altitude storage plants that, besides generating quasi CO2-free electricity, have also other benefits like protection from natural haz- ards and water supply for irrigation. Extending existing storage lakes by heightening of their dams is a complementary option to create additional storage with generally low environmental impact and possibly higher public acceptance. Both the environmental legislation and economic and market conditions currently hinder investment in HP infrastructure. Regarding legal conditions, certain energy infrastructure has been declared to be of "national interest" in the Swiss Energy Act. However, wetlands of national importance are excluded from this weighing of interest, limiting hence the HP development potential at retreating glaciers that feature such protected wetlands in their forefields. Regarding market environments and general framework conditions, the major uncertainties during typical concession periods of 80 years in combination with long planning and approval procedures do not foster investments in HP. The target values of the ES 2050 in terms of annual generation by HP can be met only in an upper-bound scenario, which would require more favourable framework conditions for HP than today. Otherwise, a intermediate scenario is more realistic, according to which the annual generation is expected to increase by 0.5 TWh/a until 2050, which is well below the target of 2.6 TWh/a. A lower-bound scenario predicts a decrease by -3.0 TWh/a, mainly due to mitigation measures to fulfill the Waters Protection Act, with reductions in generation primarily from increased residual flow requirements. In terms of energy storage, an effective increase of 1.2 TWh by 2050 is forecast in the intermediate scenario including dam heightening and a few new periglacial storage HP plants. Such an increase would correspond to almost 20 % of today’s energy storage capacity of the Swiss HP reservoirs. It is expected that the increase of storage capacity of 2 TWh by 2040 envisaged in the recently revised draft version of the Electricity Supply Act cannot be implemented by HP within this rather short time frame. However, setting such targets is important. All in all, significant efforts are required to maintain the electricity generation from HP around its current level. Potential increases are very limited because a high share of the Swiss HP generation potential is already exploited. In contrast to generation, the storage capabilities of HP shall be significantly expanded because more large-scale seasonal storage is an essential prerequisite for the efficient integration of a higher share of RES into the electricity supply system.

ETH Zurich2021