Research at LTQE focuses on the following areas in combination with the Drinking Water Chemistry Group at Eawag:
Micropollutants: Development of a web-based tool for the prediction of transformation products of micropollutants formed during oxidation processes. This tool will include both published information and new research results on kinetics and mechanisms or oxidative transformation processes. It will be based on chemical structure recognition, QSAR analyses and quantum chemical calculations to predict the extent and products of transformation of micropollutants in oxidative processes. This will enable scientist and practitioners to obtain information on the efficiency of transformation of conventional and emerging contaminants.
Toxicological assessment of transformation products: The successful research line on the toxicological assessment of oxidatively formed transformation products from micropollutants will be continued with various biological endpoints (estrogenicity, antibacterial activity, EROD activity, algal toxicity, mutagenicity, genotoxicity, etc.)
Oxidation by-products: Studies on the formation of undesired oxidation by-products from the water matrix components will focus on nitrogenous products such as nitro- and nitroso- compounds which are of high toxicological concern. The role of bromide in the formation of these products has been overlooked in the past. In many oxidation processes bromide can play an important role as a catalyst. Therefore, kinetic and mechanistic studies on bromide in oxidation processes are carried out. To improve the understanding of the formation of halo-organic compounds, stable isotope techniques (GC-IRMS) will be applied. Furthermore, in a related project the formation and mitigation of trichloramines in indoor swimming pools is investigated.
Novel treatment and monitoring systems
Removal of halide ions: Oxidation of bromide- and iodide-containing waters may lead to the formation of undesired and sometimes toxic halo-organic compounds. Novel treatment methods for the mitigation of bromide- and iodide-related oxidation by-products will be developed. They are based on silver-doped carbon aerogels, silver nano particles, quenching of HOBr by polyphenols and selective oxidation of iodide to iodate.
Hybrid treatment systems: Hybrid treatment systems are able to reach various treatment goals in one treatment step and are therefore interesting options for systems requiring compact and flexible units. Processes such as novel membrane-based ozone contactors for disinfection and advanced oxidation processes, combination of ozone with PAC and ceramic membranes for disinfection and removal of micropollutants, UV-LEDs for disinfection and catalytic oxidation (combined with e.g. TiO2), VUV for disinfection and oxidation, inline ozonation or chlorination in combination with activated carbon filters (small scale filters) for disinfection and (advanced) oxidation, “activated carbon” membranes based on carbon aerogels for combined filtration and removal of micropollutants, ferrate(VI) for combined oxidation and phosphate removal, etc. will be investigated.
Water reuse: Globally, there is an increased demand for drinking water, which can only be provided by water reuse in many situations. The advantages and consequences of oxidation processes in RO-based systems will be investigated in LTQE in collaboration with Curtin University in Perth, WA.
Monitoring of water quality: In connection with small-scale, point of entry and point of use systems, novel monitoring options for water quality control at community or household level, possibly at the tap, become essential. Sensors for residual disinfectants, hygienic parameters, heavy metals, etc. will be needed. These parameters could also be partially substituted by proxies such as T, pH, conductivity, UV, redox potential, etc. for which reliable sensors already exist. Although these sensors will not be developed at LTQE, collaboration with other working groups and companies in this field is planned. One outcome could be the development of a
Anthropogenic influence on drinking water quality
Climate change: Riverbank filtration is a major source for drinking water in Switzerland (25-30%). The riverbank is often the only barrier between the river and the drinking water. In an SNF-funded project the effect of climate change on riverbank filtration is investigated (T, contribution of wastewater), with a main focus on photochemical transformation of micropollutants in rivers, biogeochemical changes in the infiltration zone and their consequence for micropollutant transformation.
Enhanced wastewater treatment: The planned enhanced treatment of wastewater effluents (ozonation, PAC) will improve the water quality in rivers with regard to micropollutants and DOC concentration. The consequences of this improvements will be investigated in relation to effects of climate change.
Competence Center for Drinking Water (CCDW) at Eawag:
The CCDW includes various aspects of water supply systems in Switzerland and industrialized countries, such as availability of drinking water, drinking water quality, new technologies, policy/governance, consumption, water resources protection, infrastructure, climate change, demographic development etc. Many of these issues are highly interdisciplinary and the participation of stakeholders from practice will be essential. The CCDW has been launched in September 2010 and is currently in a phase of project development. Even though the CCDW is based at Eawag, researchers from EPFL will also be included in its activities.