Mount Pleasant, Zimbabwe
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Vital M.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Dignum M.,Waternet | Magic-Knezev A.,Het Waterlaboratorium HWL | Ross P.,Technical University of Delft | And 2 more authors.
Water Research | Year: 2012

An ever-growing need exists for rapid, quantitative and meaningful methods to quantify and characterize the effect of different treatment steps on the microbiological processes and events that occur during drinking water treatment and distribution. Here we compared cultivation-independent flow cytometry (FCM) and adenosine tri-phosphate (ATP) analysis with conventional cultivation-based microbiological methods, on water samples from two full-scale treatment and distribution systems. The two systems consist of nearly identical treatment trains, but their raw water quality and pre-treatment differed significantly. All of the drinking water treatment processes affected the microbiological content of the water considerably, but once treated, the finished water remained remarkably stable throughout the distribution system. Both the FCM and ATP data were able to describe the microbiology of the systems accurately, providing meaningful process data when combined with other parameters such as dissolved organic carbon analysis. Importantly, the results highlighted a complimentary value of the two independent methods: while similar trends were mostly observed, variations in ATP-per-cell values between water samples were adequately explained by differences in the FCM fingerprints of the samples. This work demonstrates the value of alternative microbial methods for process/system control, optimization and routine monitoring of the general microbial quality of water during treatment and distribution. © 2012 Elsevier Ltd.

Soshinskaya M.,University Utrecht | Crijns-Graus W.H.J.,University Utrecht | van der Meer J.,Waternet | Guerrero J.M.,University of Aalborg
Applied Energy | Year: 2014

This research explores the techno-economic potential for a predominantly renewable electricity-based microgrid serving an industrial-sized drink water plant in the Netherlands. Grid-connected and stand-alone microgrid scenarios were modeled, utilizing measured wind speed and solar irradiation data, real time manufacturer data for technology components, and a bottom-up approach to model a flexible demand from demand response. The modeled results show that there is a very high potential for renewable electricity at the site, which can make this drink water treatment plant's electricity consumption between 70% and 96% self-sufficient with renewable electricity from solar PV and wind power production. The results show that wind production potential is very high onsite and can meet 82% of onsite demand without adding solar PV. However, PV production potential is also substantial and provides a more balanced supply which can supply electricity at times when wind production is insufficient. Due to the supplemental supply over different parts of the day, adding solar PV also increases the benefits gained from the demand response strategy. Therefore, a solar-wind system combination is recommended over a wind only system. A 100% renewable system would require extremely large battery storage, which is not currently cost effective. Ultimately, even at the low wholesale electricity and sell-back price for large electricity consumers, grid-connection and the ability to trade excess electricity is extremely important for the cost-effectiveness of a microgrid system. © 2014 Elsevier Ltd.

News Article | September 20, 2016

The research will be carried out over the course of five years(Credit: MIT Senseable City Lab / AMS Institute) Autonomous cars are generating a lot of headlines at the moment, but they aren't the only vehicles being freed from the shackles of human control. In what is billed as the world's first major research program on autonomous floating vessels in metropolitan areas, autonomous boats will soon be deployed to self-navigate the winding canals of Amsterdam, Netherlands. The €25 million (US$28 million) Roboat research program will be carried out over the course of five years. It will look at the potential of using autonomous craft for transporting people and moving goods, while also investigating the potential of portable infrastructure and environmental sensing. The thinking behind research into portable infrastructure is to come up with new ways to extend the shoreline through temporary structures like on-demand stages, bridges and platforms that can quickly be assembled and dismantled. These could be used on occasions when a city's population has increased for some reason, such as during rush hour or a festival. The research into environmental sensing, meanwhile, will investigate how the so-called Roboats can be used to gather data on things like water quality, air quality and noise. This could in turn be used to tackle things like floating waste, come up with better ways to dredge the 12,000 bikes that end up in the canals each year and, with the help of underwater robots, detect waterborne diseases. The program is a joint effort between the Amsterdam Institute for Advanced Metropolitan Solutions (AMS Institute), MIT, Delft University of Technology and Wageningen University and Research. Waternet, the City of Amsterdam and the City of Boston are also supporting the program. According to the AMS Institute, the research will see Roboats of different sizes and shapes tested with a view to seeing which versions work the best. You can expect the first autonomous vessels to set sail next year.

Mons M.N.,KWR Watercycle Research Institute | Heringa M.B.,KWR Watercycle Research Institute | van Genderen J.,KWR Watercycle Research Institute | Puijker L.M.,KWR Watercycle Research Institute | And 6 more authors.
Water Research | Year: 2013

Ongoing pollution and improving analytical techniques reveal more and more anthropogenic substances in drinking water sources, and incidentally in treated water as well. In fact, complete absence of any trace pollutant in treated drinking water is an illusion as current analytical techniques are capable of detecting very low concentrations. Most of the substances detected lack toxicity data to derive safe levels and have not yet been regulated. Although the concentrations in treated water usually do not have adverse health effects, their presence is still undesired because of customer perception. This leads to the question how sensitive analytical methods need to become for water quality screening, at what levels water suppliers need to take action and how effective treatment methods need to be designed to remove contaminants sufficiently. Therefore, in the Netherlands a clear and consistent approach called 'Drinking Water Quality for the 21st century (Q21)' has been developed within the joint research program of the drinking water companies. Target values for anthropogenic drinking water contaminants were derived by using the recently introduced Threshold of Toxicological Concern (TTC) approach. The target values for individual genotoxic and steroid endocrine chemicals were set at 0.01 μg/L. For all other organic chemicals the target values were set at 0.1 μg/L. The target value for the total sum of genotoxic chemicals, the total sum of steroid hormones and the total sum of all other organic compounds were set at 0.01, 0.01 and 1.0 μg/L, respectively. The Dutch Q21 approach is further supplemented by the standstill-principle and effect-directed testing. The approach is helpful in defining the goals and limits of future treatment process designs and of analytical methods to further improve and ensure the quality of drinking water, without going to unnecessary extents. © 2013 Elsevier Ltd.

van der Hoek J.P.,Waternet | van der Hoek J.P.,Technical University of Delft
Water Practice and Technology | Year: 2011

Waternet, the first water cycle company in the Netherlands, is responsible for drinking water treatment and distribution, wastewater collection and treatment, and watersystem management and control in and around Amsterdam. Waternet has the ambition to operate climate neutral in 2020. To realise this ambition, measures are required to compensate for the emission of 53,000 ton CO 2-eq/year. Energy recovery from the water cycle looks very promising. From wastewater, ground water, surface water and drinking water, all elements of the water cycle, renewable energy can be recoverd. This can be thermal energy and chemical energy. First calculations reveal that energy recovery from the water cycle in and around Amsterdam can contribute to a total reduction in green house gas emissions up to 148,000 ton CO 2-eq/year. The challenge for the coming years is to choose robust combinations of all the possibilities to fulfil the energy demand at any time. Only then the use of fossil fuel can be abandoned and the target of operating climate neutral in 2020 can be reached. © IWA Publishing 2011.

Ruiken C.J.,Waternet | Breuer G.,Technical University of Delft | Klaversma E.,Waternet | Santiago T.,Waternet | van Loosdrecht M.C.M.,Technical University of Delft
Water Research | Year: 2013

Application of fine-mesh sieves (<0.35 mm) as pretreatment for municipal biological wastewater treatment gives an opportunity to recover resources and increase sustainability of wastewater treatment processes. Sieves are traditionally used for single stage mechanical treatment (typical mesh of 0.35 mm) or in combination with an MBR (typical mesh >0.7 mm). When sieves with a mesh of 0.35 mm are used on raw sewage we observed that cellulose fibres mainly originating from toilet paper are removed efficiently from the influent with a high recovery and purity. The application of sieves as pretreatment for conventional activated sludge processes has been evaluated based on pilot plant research at three WWTPs in the Netherlands. With sieving applied to the dry weather flow only the overall energy usage of the WWTP including sludge treatment can be decreased by at least 40% with a payback time of 7 years. © 2012 Elsevier Ltd.

Bichai F.,Ecole Polytechnique de Montréal | Barbeau B.,Ecole Polytechnique de Montréal | Dullemont Y.,Waternet | Hijnen W.,KWR Watercycle Research Institute
Water Research | Year: 2010

The significance of zooplankton in the transport and fate of pathogenic organisms in drinking water is poorly understood, although many hints of the role of predation in the persistence of microorganisms through water treatment processes can be found in literature. The objective of this study was to assess the impact of predation by natural zooplankton on the transport and fate of protozoan (oo)cysts in granular activated carbon (GAC) filtration process. UV-irradiated unlabelled Cryptosporidium parvum and Giardia lamblia (oo)cysts were seeded into two pilot-scale GAC filtration columns operated under full-scale conditions. In a two-week period after seeding, a reduction of free (oo)cysts retained in the filter bed was observed. Zooplankton was isolated from the filter bed and effluent water on a 30 μm net before and during the two-week period after seeding; it was enumerated and identified. Rotifers, which are potential predators of (oo)cysts, accounted for the major part of the isolated zooplankton. Analytical methods were developed to detect (oo)cysts internalized in natural zooplankton isolated from the filter bed and effluent water. Sample sonication was optimized to disrupt zooplankton organisms and release internalized microorganisms. (Oo)cysts released from zooplankton after sonication were isolated by IMS and stained (EasyStain™) for microscopic counting. Both Cryptosporidium and Giardia (oo)cysts were detected in association with zooplankton in the filter bed samples as well as in the effluent of GAC filters. The results of this study suggest that predation by zooplankton can play a role in the remobilization of persistent pathogens such as Cryptosporidium and Giardia (oo)cysts retained in GAC filter beds, and consequently in the transmission of these pathogens in drinking water. © 2009 Elsevier Ltd. All rights reserved.

Ghasimi D.S.M.,Technical University of Delft | de Kreuk M.,Technical University of Delft | Maeng S.K.,Sejong University | Zandvoort M.H.,Waternet | van Lier J.B.,Technical University of Delft
Applied Energy | Year: 2016

Sieving of Dutch raw sewage over a 350μm screen, produces a cake layer called fine sieved fraction (FSF), an energy-rich material that contains mainly cellulosic fibers originating from toilet paper. The FSF biomethane potential (BMP) was studied under both mesophilic (35°C) and thermophilic (55°C) conditions, whereas the stability of the fed-batch digesters at both 35°C and 55°C was researched by varying the inoculum to substrate ratios (RI / S: 0.5-15). Results clearly showed advantages of thermophilic conditions over mesophilic conditions at all tested RI / S. Stable digestion was even possible at an RI / S of 0.5 at 55°C.Following the results of the batch tests, a compact high loaded thermophilic digester for on-site energy recovery from FSF was proposed. Based on the results of the study, high biogas production rates at high organic loading rates (OLRs) were predicted. In the energy balance calculations, surplus heat production from combined heat and power (CHP) was utilized to dry the digestate sludge before transportation to an incineration plant or for use in pyrolysis or gasification processes. Overall results showed the potential of generating 46% of the required energy for wastewater treatment via high rate FSF digestion and subsequent conversion of the bio-methane into electricity and heat. The net recoverable energy from fine sieving, anaerobic digestion of FSF, dewatering of digestate sludge and drying of dewatered digestate sludge amounted 287 MJ/ton FSF and 237 kW h electric/ton FSF at 23% TS. © 2015 Elsevier Ltd.

van der Hoek J.P.,Waternet
Nederlands tijdschrift voor geneeskunde | Year: 2013

Medications and radiographic contrast dyes are sometimes detected in surface waters, ground water and drinking water; these have proven detrimental effects on organisms living in such waters The concentration of medications found in drinking water is at least a thousand times below their minimum therapeutic dosages. In humans, the long-term effects of daily exposure to low dosages of medications and 'mixture toxicity' is not known; based on the concentrations and substance toxicity, it is presumed that the risk is nil.. Physicians can play their part in controlling the problem of medications becoming part of the water cycle by taking this into account when prescribing medications. Users can make a difference by handling their medications with care and by returning all unused portions to the pharmacy. The pharmaceutical industry can also do its part by taking degradability, options for removal and the environmental effects of medications into account during their stages of development.

Ouyang X.,VU University Amsterdam | Leonards P.,VU University Amsterdam | Legler J.,VU University Amsterdam | van der Oost R.,Waternet | And 2 more authors.
Journal of Chromatography A | Year: 2015

For the first time a comprehensive two-dimensional liquid chromatography (LC. ×. LC) system coupled with a high resolution time-of-flight mass spectrometer (HR-ToF MS) was developed and applied for analysis of emerging toxicants in wastewater effluent. The system was optimized and validated using environmental standard compound mixtures of e.g. carbamate pesticides and polycyclic aromatic hydrocarbons (PAHs), to characterize the chromatographic system, to test the stability of the retention times and orthogonality. Various stationary phases in the second dimension were compared for the LC. ×. LC analysis of silicon rubber passive sampler extracts of a wastewater effluent. A combination of C18 and Pentafluorophenyl (PFP) was found to be most effective. Finally, the hyphenation of LC. ×. LC with HR-ToF MS was optimized, including splitter settings, transfer of data files between the different software packages and background subtraction using instrument software tools, after which tentative identification of 20 environmental contaminants was achieved, including pesticides, pharmaceuticals and food additives. As examples, three pesticides (isoproturon, terbutryn and diazinon) were confirmed by two-dimensional retention alignment. © 2014 Elsevier B.V.

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