Oosterhuis M.,Water Board Regge en Dinkel |
Sacher F.,Karlsruhe Institute of Technology |
ter Laak T.L.,KWR Watercycle Research Institute
Science of the Total Environment | Year: 2013
Local consumption data of pharmaceuticals were used to study the emission to wastewater and surface waters in two small Dutch water catchments. For nine high consumption pharmaceuticals: metformin, metoprolol, sotalol, losartan, valsartan, irbesartan, hydrochlorothiazide, diclofenac and carbamazepine, predicted emissions were compared to wastewater concentrations, removal in sewage treatment plants and recovery in regional surface water. The study shows that local consumption data can be very useful to select pharmaceuticals for monitoring and to predict wastewater concentrations. Measured influent concentrations were on average 78% with a range of 31-138% of predicted influent concentrations. Metformin is the pharmaceutical with the highest concentration in wastewater (64-98. μg/L) but it is removed with > 98% in sewage treatment plants (STP). Guanylurea, a biodegradation product of metformin, was detected in STP effluents and surface waters at concentrations of 39-56. μg/L and 1.8-3.9. μg/L, respectively. The STP removal of the different pharmaceuticals varied strongly. For carbamazepine, hydrochlorothiazide and sotalol a significant better removal was found at higher temperatures and longer hydraulic retention times while for metoprolol significantly better removal was only observed at higher temperatures. Predicting environmental concentrations from regional consumption data might be an alternative to monitoring of pharmaceuticals in wastewater and surface waters. © 2012 .
Van Thienen P.,KWR Watercycle Research Institute
Journal of Hydroinformatics | Year: 2013
A method, the comparison of flow pattern distributions (CFPD), is described in which the specific representation of flow measurements for two different time periods allows a direct, quantitative interpretation of changes in the pattern. Two types of changes can be distinguished. The first is changes from one period to the next in demand consistent with the existing pattern, e.g. due to changing weather or changes in the population size. The second type is inconsistent changes which may be due to increased leakage. The method is successfully applied to drinking water distribution systems of different sizes and characteristics. Being data driven, it is independent of model assumptions and therefore insensitive to uncertainties therein which may hinder some other leakage determination methods. Because it is simple to implement and apply but nevertheless powerful in distinguishing between consistent and inconsistent changes in water demand, the method provides water companies with a way to constantly monitor their networks for possible changes in customer demand and the possible occurrence of new leakages and also check archived data for similar changes. This could render additional information about customer behavior and the evolving condition of the network from data which is usually readily available at water companies. © IWA Publishing 2013.
Frijns J.,KWR Watercycle Research Institute |
Hofman J.,KWR Watercycle Research Institute |
Nederlof M.,KWR Watercycle Research Institute
Energy Conversion and Management | Year: 2013
Next to energy efficiency improvements in the water sector, there is a need for new concepts in which water is viewed as a carrier of energy. Municipal wastewater is a potential source of chemical energy, i.e. organic carbon that can be recovered as biogas in sludge digestion. The recovery of chemical energy can be maximised by up-concentration of organic carbon and maximised sludge digestion or by source separation and anaerobic treatment. Even more so, domestic wastewater is a source of thermal energy. Through warm water conservation and heat recovery, for example with shower heat exchangers, substantial amounts of energy can be saved and recovered from the water cycle. Water can also be an important renewable energy source, i.e. as underground thermal energy storage. These systems are developing rapidly in the Netherlands and their energy potential is large. © 2012 Elsevier Ltd. All rights reserved.
Van Der Wielen P.W.J.J.,KWR Watercycle Research Institute |
Medema G.,KWR Watercycle Research Institute
Applied and Environmental Microbiology | Year: 2010
Bacteroidales species were detected in (tap) water samples from treatment plants with three different PCR assays. 16S rRNA gene sequence analysis indicated that the sequences had an environmental rather than fecal origin. We conclude that assays for Bacteroidales 16S rRNA genes are not specific enough to discern fecal contamination of drinking water in the Netherlands. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
van der Wielen P.W.J.J.,KWR Watercycle Research Institute |
van der Kooij D.,KWR Watercycle Research Institute
Water Research | Year: 2010
The objective of our study was to determine whether water composition, distance to the treatment plant and season significantly affect the adenosine triphosphate (ATP) concentration in distributed drinking water, in order to resolve the suitability of ATP as an indicator parameter for microbial regrowth. Results demonstrated that the ATP concentration in distributed water averaged between 0.8 and 12.1 ng ATP L-1 in the Netherlands. Treatment plants with elevated biofilm formation rates in treated water, showed significantly higher ATP concentrations in distributed drinking water and ATP content was significantly higher in the summer/autumn compared to the winter period at these plants. Furthermore, transport of drinking water in a large-sized distribution system resulted in significantly lower ATP concentrations in water from the distal than the proximal part of the distribution system. Finally, modifications in the treatment significantly affected ATP concentrations in the distributed drinking water. Overall, the results from our study demonstrate that ATP is a suitable indicator parameter to easily, rapidly and quantitatively determine the total microbial activity in distributed drinking water. © 2010 Elsevier Ltd.
Bonte M.,KWR Watercycle Research Institute |
Zwolsman J.J.G.,KWR Watercycle Research Institute
Water Research | Year: 2010
In this paper we present a modelling study to investigate the impacts of climate change on the chloride concentration and salinisation processes in two man-made freshwater lakes in the Netherlands, Lake IJsselmeer and Lake Markermeer. We used a transient compartmental chloride and water balance model to elucidate the salinisation processes occurring under present conditions and assess future salinisation under two climate forcing scenarios. The model results showed that the Rhine River is the dominant determinant for the chloride concentration in both lakes, followed by drainage of brackish groundwater from the surrounding polders. The results further show that especially during dry years, seawater intrusion through the tidal closure dam is an important source of chloride to Lake IJsselmeer. The results from the climatic forcing scenarios show that Lake IJsselmeer is especially vulnerable to climate-induced salinisation whereas effects on Lake Markermeer are relatively small. Peak chloride concentrations at the raw water intake of the Andijk drinking water facility on Lake IJsselmeer are projected to increase to values above 250 mg/l in the most far-reaching climate change scenario W+ in 2050 for dry years. This is well above the maximum allowable concentration of 150 mg/l for chloride in drinking water.Modelling showed that climate change impacts the chloride concentrations in a variety of ways: 1) an increasing occurrence of low river flows from summer to autumn reduces the dilution of the chloride that is emitted to the Rhine with a constant load thereby increasing its concentration; 2) increased open water evaporation and reduced rainfall during summer periods and droughts increases the chloride concentration in the water; and 3) rises in sea level increase seawater intrusion through the tidal closure dam of Lake IJsselmeer. The processes described here are likely to affect many other tidal rivers or lakes and should be considered when planning future raw water intake stations for drinking water production or agricultural water supply. © 2010 Elsevier Ltd.
Wols B.A.,KWR Watercycle Research Institute |
Wols B.A.,Technical University of Delft |
Hofman-Caris C.H.M.,KWR Watercycle Research Institute
Water Research | Year: 2012
Emerging organic contaminants (pharmaceutical compounds, personal care products, pesticides, hormones, surfactants, fire retardants, fuel additives etc.) are increasingly found in water sources and therefore need to be controlled by water treatment technology. UV advanced oxidation technologies are often used as an effective barrier against organic contaminants. The combined operation of direct photolysis and reaction with hydroxyl radicals ensures good results for a wide range of contaminants. In this review, an overview is provided of the photochemical reaction parameters (quantum yield, molar absorption, OH radical reaction rate constant) of more than 100 organic micropollutants. These parameters allow for a prediction of organic contaminant removal by UV advanced oxidation systems. An example of contaminant degradation is elaborated for a simplified UV/H 2O 2 system. © 2012 Elsevier Ltd.
Bichai F.,Harvard University |
Smeets P.W.M.H.,KWR Watercycle Research Institute
Water Research | Year: 2013
Innovation in the water sector is at play when addressing the global water security challenge. This paper highlights an emerging role for Quantitative Microbial Risk Assessment (QMRA) and health-based targets in the design and application of robust and flexible water quality regulation to protect public health. This role is especially critical as traditional supply sources are subject to increased contamination, and recycled wastewater and stormwater become a crucial contribution to integrated water supply strategies. Benefits and weaknesses of QMRA-based regulation are likely to be perceived differently by the multiple stakeholders involved. The goal of the current study is to evaluate the experience of QMRA-based regulation implementation in the Netherlands and Australia, and to draw some lessons learned for regulators, policy makers, the industry and scientists. Water experts from regulatory bodies, government, water utilities, and scientists were interviewed in both countries. This paper explores how QMRA-based regulation has helped decision-making in the Netherlands in drinking water safety management over the past decade. Implementation is more recent in Australia: an analysis of current institutional barriers to nationally harmonized implementation for water recycling regulation is presented. This in-depth retrospective analysis of experiences and perceptions highlights the benefits of QMRA-based regulation and the challenges of implementation. QMRA provides a better assessment of water safety than the absence of indicators. Setting a health target addresses the balance between investments and public safety, and helps understand risks from alternative water sources. Challenges lie in efficient monitoring, institutional support for utilities, interpretation of uncertainty by regulators, and risk communication to consumers. © 2013 Elsevier Ltd.
Frijns J.,KWR Watercycle Research Institute
Water and Environment Journal | Year: 2012
This paper describes the carbon footprint methodology used in assessing the global warming potential of the Dutch water sector. The assessment includes CO 2 emissions from energy consumption and methane and nitrous oxide emissions from water treatment processes. There is, however, debate on the amounts and mechanism of greenhouse gas (GHG) emissions, and a standardised approach is discussed. As a result of this approach, the contribution of GHG emissions to the total carbon footprint of the Dutch water sector appeared to be relatively high. Next to the lack of common emission factors for GHG and chemicals used, there is also no agreed-upon approach related to the system boundaries and scope of carbon footprinting of the water cycle. For reasons of benchmarking and monitoring of climate change reduction targets, a common carbon footprint assessment methodology for the water sector will be required. © 2011 The Author. Water and Environment Journal © 2011 CIWEM.
van der Wielen P.W.J.J.,KWR Watercycle Research Institute |
van der Kooij D.,KWR Watercycle Research Institute
Applied and Environmental Microbiology | Year: 2013
The multiplication of opportunistic pathogens in drinking water supplies might pose a threat to public health. In this study, distributed unchlorinated drinking water from eight treatment plants in the Netherlands was sampled and analyzed for fungi, nontuberculous mycobacteria (NTM), and several opportunistic pathogens by using selective quantitative PCR methods. Fungi and NTM were detected in all drinking water samples, whereas Legionella pneumophila, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Aspergillus fumigatus were sporadically observed. Mycobacterium avium complex and Acanthamoeba spp. were not detected. Season had no influence on the occurrence of these organisms, except for NTM and S. maltophilia, which were present in higher numbers in the summer. Opportunistic pathogens were more often observed in premise plumbing water samples than in samples from the distribution system. The lowest number of these organisms was observed in the finished water at the plant. Thus, fungi, NTM, and some of the studied opportunistic pathogens can multiply in the distribution and premise plumbing systems. Assimilable organic carbon (AOC) and/or total organic carbon (TOC) had no clear effects on fungal and NTM numbers or on P. aeruginosa- and S. maltophilia-positive samples. However, L. pneumophila was detected more often in water with AOC concentrations above 10μg C liter-1 than in water with AOC levels below 5μg C liter-1. Finally, samples that contained L. pneumophila, P. aeruginosa, or S. maltophilia were more frequently positive for a second opportunistic pathogen, which shows that certain drinking water types and/or sampling locations promote the growth of multiple opportunistic pathogens. © 2013, American Society for Microbiology.