PWN Water Supply Company North Holland

Andijk, Netherlands

PWN Water Supply Company North Holland

Andijk, Netherlands
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Vrouwenvelder J.S.,Center of Excellence for Sustainable Water Technology | Vrouwenvelder J.S.,Technical University of Delft | Beyer F.,Center of Excellence for Sustainable Water Technology | Beyer F.,Friedrich - Schiller University of Jena | And 6 more authors.
Water Research | Year: 2010

Phosphate limitation as a method to control biofouling of spiral wound reverse osmosis (RO) membranes was studied at a full-scale installation fed with extensively pretreated water. The RO installation is characterized by (i) a low feed channel pressure drop increase and (ii) low biomass concentrations in membrane elements at the installation feed side. This installation contrasted sharply with installations fed with less extensively pretreated feed water (and therefore higher phosphate concentrations) experiencing a high-pressure drop increase and high biomass concentrations in lead elements. Membrane fouling simulator (MFS) studies showed that low phosphate concentrations (∼0.3 μg P L-1) in the feed water restricted the pressure drop increase and biomass accumulation, even at high substrate (organic carbon) concentrations. In the MFS under ortho-phosphate limiting conditions, dosing phosphonate based antiscalants caused biofouling while no biofouling was observed when acids or phosphonate-free antiscalants were used. Antiscalant dosage could increase both phosphate and substrate concentrations of the water. Therefore, antiscalant selection may be critical for biofouling control. Since no biofouling was observed at low phosphate concentrations, restricting biomass growth by phosphate limitation may be a feasible approach to control biofouling, even in the presence of high organic carbon levels. © 2010 Elsevier Ltd.

Martijn B.J.,PWN Water Supply Company North Holland | Fuller A.L.,University of New Hampshire | Malley J.P.,University of New Hampshire | Kruithof J.C.,Center of Excellence for Sustainable Water Technology
Ozone: Science and Engineering | Year: 2010

PWN considers ion exchange and ultrafiltration (IX-UF) for replacing the existing CSF pretreatment at the Andijk water treatment plant. Advanced oxidation (UV/H2O2) in combination with granular activated carbon filtration (GAC) as a non selective barrier against organic micro pollutants is operational since 2004. Effects of an improved pretreatment on the UV/ H2O2 in terms of direct photolysis, OH-radical oxidation and energy consumption are presented in this paper. NDMA and 1,4-dioxane are selected to show the impact of pretreatment on UV photolysis and hydroxyl radical oxidation, respectively. Key water quality parameters are DOC and nitrate for scavenging and competition for UV light. Compared to CSF, the electrical energy per order (EEO) for IX-UF treated water was reduced with about 50%. © 2010 International Ozone Association.

Galjaard G.,PWN Water Supply Company North Holland | Martijn B.,PWN Water Supply Company North Holland | Koreman E.,PWN Water Supply Company North Holland | Bogosh M.,University of New Hampshire | Malley J.,University of New Hampshire
Water Practice and Technology | Year: 2011

This paper reviews the progress that has been made during the last four years within the research facilities of PWN. This has resulted in a new pre-treatment process for the direct treatment of water containing high amounts of suspended matter, dissolved organic carbon and nitrate, such as surface waters, based on ion exchange (SIX®) and ceramic microfiltration (Ceramac®). This paper specifically reviews the results of a performance evaluation that has been made of this new pre-treatment process in comparison with conventional pre-treatment techniques, in this case enhanced coagulation followed by rapid sand filtration. Based on the outcome of this study a new treatment facility has been designed with these new processes which will be operational in 2013 with a capacity of 5000m3/h, this comparison study however is based on a maximum capacity of 4000 m 3/h. This new pre-treatment leads to a superior water quality, reduced energy consumption, less waste and a smaller carbon footprint. © IWA Publishing 2011.

Martijn A.J.,PWN Water Supply Company North Holland | Martijn A.J.,Center of Excellence for Sustainable Water Technology | Kruithof J.C.,Center of Excellence for Sustainable Water Technology
Ozone: Science and Engineering | Year: 2012

Since Rook showed the production of trihalomethanes by drinking water chlorination, reaction product formation by chemical disinfection/oxidation has been thoroughly investigated. Originally, the focus was on the formation of individual organic products. After chlorination, trihalomethanes (THMs), haloacetic acids (HAAs) and many other halogenated compounds were found. After ozonation, ultraviolet (UV) disinfection and advanced oxidation, biodegradable organic by-products such as carboxylic acids were identified. All reaction products were formed by reaction with the organic water matrix (natural organic matter).Formation of reaction products from the inorganic water matrix proved to be an important issue as well. By ozonation and ozone-based advanced oxidation processes bromate was formed in bromide-rich water. By UV and UV/H 2O 2 treatment, nitrite was formed in nitrate rich water, especially when medium pressure (MP) UV lamps were applied. In addition to chemical characterization of individual reaction products the side effects of disinfection/ oxidation were investigated by genotoxicity testing. After chlorination a high response was found in the classic Ames test. After ozone and ozone based advanced oxidation a decrease of the response in the classic Ames test was observed, while after UV disinfection and UV-based advanced oxidation no significant effect was found. Modified genotoxicity testing such as in vitro Ames-II has been developed and applied on UV/H 2O 2-treated water. Once again no or just a small significant genotoxic response was observed after MP UV/H 2O 2 treatment in a system equipped with natural quartz sleeves. However, a substantially higher response was found after MP UV/H 2O 2 treatment in a system equipped with synthetic sleeves with a higher transmittance at lower wavelengths. The genotoxic response and the nitrite formation increased in the same order of magnitude, suggesting a relationship with the UV photolysis of nitrate. This was confirmed by UV photolysis of natural organic matter (NOM) and nitrate containing reconstituted water. The genotoxic effect was removed completely by post-treatment with granular activated carbon (GAC) filtration and/or dune infiltration. © 2012 Copyright 2012 International Ozone Association.

Martijn A.J.,PWN Water Supply Company North Holland | Martijn A.J.,Center of Excellence for Sustainable Water Technology | Boersma M.G.,Wageningen University | Vervoort J.M.,Wageningen University | And 2 more authors.
Desalination and Water Treatment | Year: 2014

Abstract: Genotoxic compounds were produced by full-scale medium pressure (MP) ultraviolet hydrogen peroxide (UV/H2O2) treatment of nitrate-rich pretreated surface water. It was hypothesized that this formation was caused by the reaction of nitrate photolysis intermediates with natural organic matter (NOM). An increase in the Ames test response was also found after MP UV photolysis of water containing Pony Lake NOM from the International Humic Substances Society (IHSS) and nitrate, while no increase in the Ames test response was found when nitrate was absent. The same trend in an Ames test response and nitrite formation was observed for both nitrate-rich pretreated surface water and reconstituted water containing NOM and nitrate. Therefore, the conversion of nitrate by MP UV photolysis was studied in several water types. In organic-free water, nitrate was completely converted into nitrite, while no inorganic nitrogen was lost. Also in nitrate-rich surface water, nitrite was found as the only inorganic reaction product, while a small decrease of the inorganic nitrogen content was observed. When NOM was replaced by phenol, MP UV photolysis caused a restricted nitrite formation only, together with a large loss of inorganic nitrogen. The formation of the nitrated phenol derivatives, 2- and 4-nitrophenol and 4-nitrocatechol, was observed with highest concentrations under practical UV conditions. It is hypothesized that the formation of nitrated aromatic compounds is the cause of the increased Ames test response by MP UV treatment. © 2014, © 2014 Balaban Desalination Publications. All rights reserved.

Kruithof J.C.,Center of Excellence for Sustainable Water Technology | Martijn B.J.,Center of Excellence for Sustainable Water Technology | Martijn B.J.,PWN Water Supply Company North Holland
Water Science and Technology: Water Supply | Year: 2013

The presence of pesticides, endocrine disruptors and pharmaceuticals caused PWN to implement multiple barriers for organic contaminant control in their surfacewater treatment plants. A combination of advanced oxidation by UV/H 2O2 treatment and granular activated carbon (GAC) filtration is installed. Medium pressure UV experiments in a standard pilot reactor have been carried out into the degradation of a representative selection of pesticides found in PWN's main raw water source, the IJssel Lake. It was observed that atrazine and diuron are more sensitive to direct photodegradation while bentazone and bromacil are primarily degraded by hydroxyl radical oxidation. Addition of H2O2 increased the decay rate of all selected herbicides. Using computational fluid dynamics, irradiance distribution and kinetic models developed by Trojan Technologies Inc., an optimized UV-reactor was designed. In tests with a pilot reactor according to this new design, the predicted performance was confirmed, both for photodegradation and hydroxyl radical oxidation. During the research period, the scope broadened from pesticides to pharmaceuticals, endocrine disrupting compounds, solvents and algae toxins. At process conditions 0.56 kWh/m 3 and 6 mg/L H2O2, 80-100% degradation was achieved for compounds such as mecoprop, clofibric acid and diclofenac. A somewhat lower degradation was found for dicamba, 2, 4-D, bentazone, ibuprofen, carbamazepine and sulphametoxalol. The developed modelling was used to design a full scale UV/H2O2 system with an electric energy of 0.56 kWh/m3 for treatment of 3,000 m3/h. In a site acceptance test, degradation of atrazine was measured at two UV-doses at a fixed H 2O2 dose of 6 mg/L. The installation performed as predicted by the design models and design criteria were met. At wtp Andijk, UV/H2O2 is integrated in the existing process train, preceded by conventional surface water treatment (coagulation, sedimentation and filtration) and followed by GAC filtration providing a robust barrier against reaction products from both oxidation and photolytic degradation (assimilable organic carbon, nitrite). Replacing the conventional pretreatment by ion exchange followed by ceramicmicrofiltration will further improve the economics of UV/H2O2 treatment. Copyright © IWA Publishing 2013.

Worm G.I.M.,PWN Water Supply Company North Holland | Worm G.I.M.,Technical University of Delft | van der Helm A.W.C.,Technical University of Delft | Lapikas T.,UReason | And 3 more authors.
Environmental Modelling and Software | Year: 2010

Water supply companies are gradually changing to a centralised, fully automated operation. The drivers for this change are the increase in efficiency and a better and more stable water quality. Fully automated treatment plants will require more sophisticated operator care than manually operated plants, so operation supervisors should periodically train in a drinking water treatment plant simulator. The successful first time setup of such a simulator is addressed in this paper. Environmental decision-support systems (EDSSs) were used as a blueprint for this simulator because the integration of different models is common in EDSSs. By applying a SCADA-like graphic user interface and several report options, even a group of end-users without specific modelling skills or knowledge can take advantage of the use of integrated hydraulic, water quality and process control models. The 'Waterspot' drinking water treatment plant simulator has been developed and applied to Dutch drinking water treatment plants. To demonstrate successful application, a case study is described for the drinking water treatment plant at Weesperkarspel. © 2009 Elsevier Ltd. All rights reserved.

Blokker E.J.M.,KWR Watercycle Research Institute | Blokker E.J.M.,Technical University of Delft | Vreeburg J.H.G.,KWR Watercycle Research Institute | Vreeburg J.H.G.,Technical University of Delft | And 3 more authors.
Drinking Water Engineering and Science | Year: 2010

An "all pipes" hydraulic model of a drinking water distribution system was constructed with two types of demand allocations. One is constructed with the conventional top-down approach, i.e. a demand multiplier pattern from the booster station is allocated to all demand nodes with a correction factor to account for the average water demand on that node. The other is constructed with a bottom-up approach of demand allocation, i.e., each individual home is represented by one demand node with its own stochastic water demand pattern. This was done for a drinking water distribution system of approximately 10 km of mains and serving ca. 1000 homes. The system was tested in a real life situation. The stochastic water demand patterns were constructed with the end-use model SIMDEUM on a per second basis and per individual home. Before applying the demand patterns in a network model, some temporal aggregation was done. The flow entering the test area was measured and a tracer test with sodium chloride was performed to determine travel times. The two models were validated on the total sum of demands and on travel times. The study showed that the bottom-up approach leads to realistic water demand patterns and travel times, without the need for any flow measurements or calibration. In the periphery of the drinking water distribution system it is not possible to calibrate models on pressure, because head losses are too low. The study shows that in the periphery it is also difficult to calibrate on water quality (e.g. with tracer measurements), as a consequence of the high variability between days. The stochastic approach of hydraulic modelling gives insight into the variability of travel times as an added feature beyond the conventional way of modelling. © Author(s) 2010.

Blokker E.J.M.,KWR Watercycle Research Institute | Schaap P.G.,PWN Water Supply Company North Holland
Procedia Engineering | Year: 2015

Particulate material accumulates in drinking water distribution systems (DWDS) and this can cause discolouration. To minimize customer complaints it is required to understand the influencing factors and determine an appropriate flushing frequency. The accumulation rates of two comparable DWDS were examined. Area A with a constant incoming water quality experiences a steady accumulation rate; area B with a more variable incoming water quality has a variable accumulation rate. The difference in accumulation rate is proportionate to the difference in the particle loading of the two areas and is thus largely determined by the difference in incoming water quality. The water quality into a DWDS is not only determined by the treatment works, but also by the material accumulation and resupsension in the trunk mains supplying it. Monitoring the particle loading of a DWDS part can help in determining the required flushing frequency © 2015 Published by Elsevier Ltd.

Blokker E.J.M.,KWR Watercycle Research Institute | Schaap P.G.,PWN Water Supply Company North Holland
Procedia Engineering | Year: 2015

Particulate material can accumulate in drinking water distribution systems (DWDS) and can cause discolouration. Previous research showed that temperature influences this. However, it did not explain why higher temperatures lead to a higher accumulation rates. Based on existing data collected in the DWDS of several Dutch water companies, we investigated if higher temperatures lead to more particulate material from the treatment plant, or cause higher accumulation rates within the DWDS. Continuous temperature and turbidity measurements at 6 pumping stations showed the majority of the treatment plants do not have a seasonal trend in turbidity. Filter volumes in the DWDS and high frequency particle accumulation rate measurements on numerous locations in the DWDS of one specific water company did show a seasonal effect. It is likely that higher temperatures in the DWDS can augment particulate material accumulation. © 2015 Published by Elsevier Ltd.

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