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The water sector is, currently and for the foreseeable future, challenged by rising levels of uncertainty in demand and availability of water, in a context of aging infrastructure and limited investment. In order to support strategic planning, water companies need a way to assess how their system behaves when faced with a range of changing conditions (climatic trends, asset deterioration, behavioral patterns, etc.) as well as accidents/incidents and/or extreme events (wildcards). In this study, a resilience assessment methodology was demonstrated, with 'stress tests' alternative water system configurations (including systems designed with decentralized or distributed philosophies) under a range of scenarios and extreme events. A 'resilience profile graph' was developed to quantify the performance of each configuration. The methodology was applied to the real-world urban water system of Oasen, which supplies the eastern part of the Province of South Holland, where the current system configuration and two potential future configurations were tested (one decentralized and one distributed). We show how the concept of resilience, operationalized through this methodology, can assist long term decision making and support strategic infrastructure planning., Part of the Special Issue Centralized versus Decentralized Urban Water Systems, Sanitary Engineering

The application of sulfate reducing bacteria (SRB) to treat municipal wastewater is seldom considered. For instance, due to low sludge yield it can reduce the amount of excess sludge produced significantly. Several studies, mainly at laboratory-scale, revealed that SRB can proliferate in artificial wastewater systems at temperatures of 20°C and lower. So far, the application of SRB in a domestic wastewater treatment plant has been limited. Therefore, this study evaluates the proliferation of SRB at pilot-scale in a moderate climate. This study revealed that SRB were present and active in the pilot fed with domestic wastewater at 13°C, and outcompete methanogens. Stable, smooth and well-settled granule formation occurred, which is beneficial for full-scale application. In the Netherlands the sulfate concentration is usually low (,500 mg/L), therefore the application of SRB seems challenging as sulfate is limiting. Additional measurements indicated the presence of other sulfur sources, therefore higher sulfur levels were available, which makes it possible to remove more than 75% of the chemical oxygen demand (excluding sulfide) based on SRB activity. The beneficial application of SRB to domestic wastewater treatment might therefore be valid for more locations than initially expected., BT/Environmental Biotechnology

In this project, solutions are developed to minimise leaching of nutrients and pesticides from greenhouses to the environment (esp. surface water), in order to comply with legislation and societal demands. In 2017 the following questions have been addressed: To prevent emission, drain solutions are reused or purified. Other water flows may deviate in compositionand possibilities for reuse or purification. The option for reuse or purification for these water flows has been investigated, and a working methodology for the end of a cultivation (e.g. cleaning) has been developed. Applications of Forward Osmosis in horticulture have been investigated. Water extracted from the discharge flow with Forward Osmosis using the concentrated nutrient solution holds prospects, but extracting irrigation water from brackish groundwater seems less feasible. In a long-term experiment, sodium (Na) standards for sweet pepper have been reinterpreted. It was shown that an increase in the Na standard up to 8-10 mmol/l causes no damage or loss in pepper production. Inaddition, it was shown that the split-root system can be used for uptake of extra Na without growth hampering. Furthermore, applying humate can prevent negative sodium effects at high sodium levels (Chinese cabbage). Finally, insight was gained into the risks associated with the use of chlorinated cleaning products in zero-discharge cultivations., In dit tweejarige project zijn openliggende kennisvragen opgepakt om de laatste stappen naar de gewenste nulemissie bij substraatteelten mogelijk te maken. In 2017 zijn de volgende vragen onderzocht: Voor waterstromen die sterk afwijken van gangbaar lozingswater, is de samenstelling geanalyseerd en zijn mogelijkheden tot hergebruik dan wel zuivering verkend. Tevens is onderzocht hoe bedrijven in de praktijk omgaan met deze waterstromen. Voor waterstromen die bij de teeltwisseling vrijkomen is een werkwijze ontwikkeld; in2018 komen best practices beschikbaar voor de andere waterstromen. De toepassing van Forward Osmosis in de tuinbouw is onderzocht. Voor het indikken van de spuiwaterstroom biedt Forward Osmosis met als trekvloeistof een geconcentreerde nutriëntenoplossing perspectief, voor het onttrekken van gietwater uit brak grondwater minder. In 2018 volgt een pilot proef en optimalisatie van de scenario’s. De Na-normen voor paprika zijn geherinterpreteerd met een duurproef, waarbij bleek dat een verhoging van Na-norm voor paprika tot 8-10 mmol/l veilig kan. Daarnaast is aangetoond dat de restgoot-methode (gescheiden wortelsysteem) gebruikt kan worden om extra Na op te nemen zonder negatieve gevolgen voor groei. In 2018wordt deze methode op semi-praktijkschaal getest. Ook het toedienen van humaat kan de negatieve gevolgen vaneen hoog natrium teniet doen (Chinese kool). Tenslotte is er inzicht verkregen in de risico’s bij het gebruik van chloorhoudende reinigingsmiddelen in emissieloze teelten.

This report summarizes activities in TRUST WP4 addressing optimum operation performance of water supply systems with respect to safety, environmental impacts and cost-efficiency. Optimization of water treatment plant and distribution system has to rely on selected optimization criteria that are site and system-specific in order to cope with challenges posed by e.g. stringent regulations, consumer feedback, climate change, etc. Comprehensive knowledge of the specific characteristics, limitations and challenges of a water supply system is required in order to define available alternatives and to design and perform full-scale optimization studies and trials. The proposed optimization framework includes:(i) Mapping operational performance status that includes initial performance evaluation and comparison to model predictions, (ii)Utilizing diagnostic tools, e.g. for water quality characterization that also helps identification of variations in the performance, (iii) Utilizing curative tools that includes performing experiments and optimization trials without compromising the water quality produced, (iv) Utilizing decision support systems to highlight some other aspects e.g. economic and environmental issues that are not covered by the diagnostic and curative tools, (v) Identifying performance optimization potentials and possible benefits, (vi) Implementing selected operation conditions based on overall assessments of potential advantages and disadvantages for both treatment and distribution systems. The framework has been successfully implemented in case studies in UK, The Netherlands and Norway in order to support decision for sustainable optimization of full-scale water treatment plants in the respective locations.