Matthias Maier

Removal of Iodinated X-Ray Contrast Media During Drinking Water Treatment

Environmental Context.In recent years, many micro-organic pollutants, e.g. pharmaceuticals and personal care products (PPCP), have been observed to be persisting through wastewater treatment and occurring in the environment. Persistent micropollutants are of particular concern owing to the fact that some of them have been found in drinking water, and iodinated X-ray contrast media (ICM) are one group of such pollutants. Abstract.The present study investigates the removal of five iodinated X-ray contrast media (ICM) during drinking water production from surface water at a full-scale water works, which comprises coagulation/flocculation, intermediate ozonation, in-line filtration and adsorption with activated carbon. The elimination rates over all treatment units for the non-ionic ICM (iomeprol, iopromide, iohexol and iopamidol) were determined to be approximately 70%. In particular, intermediate ozonation can remove 30% on average of the non-ionic ICM, whereas it cannot remove the ionic diatrizoic acid, and the granulated activated carbon filters can achieve a further 50% removal of non-ionic ICM. However, over 100 ng L−1 of ionic diatrizoic acid and 40–100 ng L−1 of non-ionic ICM were found in the produced drinking water.

Factors influencing the mobilisation of polycyclic aromatic hydrocarbons (PAHs) from the coal-tar lining of water mains

Abstract Coal-tar was commonly used as an internal lining for corrosion protection of water pipes from the 19th century. In this project the principal mechanisms leading to the occurrence of Polycyclic Aromatic Hydrocarbons (PAHs) in those water mains were investigated. The results showed that the occurrence of PAHs in a distribution system was linked to the presence of the disinfectants chlorine and chlorine dioxide. In laboratory experiments it was demonstrated that the coal-tar surface represents a substrate for the growth of biofilms which exhibits protective effects. Generally, hostile environmental conditions for microbiological activity of the biofilm such as disinfection, stagnation periods and anaerobic conditions could be identified as important factors which favour the occurrence of PAHs in drinking water. Immediately after stagnation periods an increase of PAH concentrations was observed. Furthermore, it was clearly shown that disturbances in the hydraulic regime such as water hammers, operation of valves and rapid increases in flow velocity can result in enhanced PAH concentrations by the destabilisation of the biofilm matrix or high shear forces affecting the pipe walls resulting in the release of particles highly contaminated with PAHs which may be responsible for the contamination of the drinking water.

Evaluation of the hazard potentials of river suspended particulate matter and floodplain soils in the Rhine basin using chemical analysis and in vitro bioassays.

The purpose of the present study was to assess the hazard potentials of contaminated suspended particulate matter (SPM) sampled during a flood event for floodplain soils using in vitro bioassays and chemical analysis. Sediment-contact tests were performed to evaluate the direct exposure of organisms to native soils and SPM at two different trophic levels. For comparison, acetonic extracts were tested using both contact tests and additionally two cell-based biotests for cytotoxicity and Ah receptor-mediated activity (EROD-Assay). The sediment-contact tests were carried out with the dehydrogenase assay with Arthrobacter globiformis and the fish embryo assay with Danio rerio. The results of this study clearly document that native samples may well be significantly more effective than corresponding extracts in the bacteria contact assay or the fish embryo test. These results question the commonly accepted concept that acetonic extracts are likely to overestimate the toxicity of soil and SPM samples. Likewise, the priority organic compounds analyzed failed to fully explain the toxic potential of the samples. The outcomes of this study revealed the insufficient knowledge regarding the relationship between the different exposure pathways. Finally, there is concern about adverse effects by settling suspended particulate matter and remobilized sediments in frequently inundated floodplain soils due to an increase of the hazard potential, if compared with infrequently inundated floodplain soils. We showed that the settling of SPM and sediments revealed a significant impact on the dioxin-like potencies of riparian soils.

Screening analysis of volatile organic contaminants in commercial inorganic coagulants used for drinking water treatment

A method for quality screening is suggested to detect volatile impurities in inorganic coagulants that are used for drinking water treatment. Static headspace gas chromatography with mass spectrometry detection (HS-GCMS) is sensitive and selective to detect volatiles in low concentrations. This study has discovered that volatile organic impurities are detectable in ferric and aluminium-based coagulants which are used for drinking water treatment. For ferric chloride, 2-propanol was detected at a level of 17-24 microg ml(-1), acetone at 0.7-1.7 microg ml(-1), 1,1,1-trichloroacetone at 0.02-0.04 microg ml(-1), trichloromethane at 0.01-0.02 microg ml(-1) and toluene at 0.01-0.12 microg ml(-1). For ferric chloride sulfate, acetone was detected at a level of 0.12 microg ml(-1), 1,1,1-trichloroacetone at 0.06-0.08 microg ml(-1), trichloromethane at 0.13-0.23 microg ml(-1), bromodichloromethane at 0.04-0.06 microg ml(-1) and dibromochloromethane at 0.04-0.05 microg ml(-1). For aluminium hydroxide chloride, only trichloromethane was detectable, but below the method detection limits (MDL). Although the concentrations of these impurities in commercial coagulants are low, this observation is important and should have impact on water industries for them to pay attention to the chemicals they are using for drinking water production.

Improvement of the Water-Energy Nexus and the Environmental Performance of Water Supply Systems using Smart ICT Solutions

In the last years, there has been a great interest in the complex interactions between energy and water, known as the Water-Energy Nexus [1]. Free and unrestricted availability and access to energy and water enables the growth of an economy and supports the quality of life. The Water-Energy Nexus is considered as one of the most important multidisciplinary challenges [2] that the water market globally growing has to face in the forthcoming years. Currently, many water systems are not managed in terms of long term sustainability. Water Utilities (WU) are faced to further challenges, such as aging of their infrastructure and poor cost-recovery, leading to a lack of finance for operation and maintenance (O&M). Energy is required in all stages of water production and distribution, from abstraction over treatment to transportation. Energy costs are a top-of-mind concern for WU, regardless of the geography, size and level of water network efficiency [3]. On the other hand, in developing countries WU are having a hard time to either improve their services or expand their network to unserved neighbourhoods. Regarding all this facts, and considering an economic and competitive scenario which forces to respond to pressures from various fields (market, technology, society...), lead to the need to implement new methods and processes that can meet these growing demands and to try to manage responses and actions in real time. Intelligent software solutions can be applied to networks, whether they have either smart metering and large amounts of data or less recorded data. They enhance the operators’ knowledge of this data, turn it into useful information for decision-making related to the operation, maintenance and the design of the water supply network. In this paper, an application of an intelligent software solution is presented. WatEner, a smart Information and Communication Technology (ICT) solution that combines the key factors of energy consumption with further operational requirements of drinking water supply to improve the management of water supply networks, has been tested with good results by the WU of the city of Karlsruhe, a water rich area in North-West Europe where the main objective was to save energy in the drinking water distribution. As a conclusion, a non-structural solution for the water-energy nexus can have a great impact on several matters (e.g. climate change, carbon footprint, WUs balance sheets, water losses) with reasonable investment in only a few sensors in the water supply network. keywords: Water-energy nexus; Drinking water supply; Water distribution network; Water supply management; Energy consumption; Water utilities; Artificial intelligence; Carbon footprint.