Institute for Water Education

Delft, Netherlands

Institute for Water Education

Delft, Netherlands
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Ilyas H.,Independent Researcher | Masih I.,Institute for Water Education
Journal of Environmental Management | Year: 2017

The effects of different aeration strategies including tidal flow (TF), effluent recirculation (ER) and artificial aeration (AA) on performance of vertical flow constructed wetland (VFCW), horizontal flow constructed wetland (HFCW) and hybrid constructed wetland (HCW) are comprehensively and critically reviewed in this paper. The removal efficiencies of nine types of intensified constructed wetlands (CWs) were examined in detail and their mean and standard deviation were estimated at 89 ± 11%, 84 ± 12%, 81 ± 17% and 63 ± 20% for total suspended solids (TSS), chemical oxygen demand (COD), ammonium-nitrogen (NH4 +[sbnd]N) and total nitrogen (TN), respectively. From the studied CWs, ER-HCW, TF-HCW, AA-VFCW and ER-VFCW emerged as the four best performing systems. The overall removal efficiency of TSS, COD, NH4 +[sbnd]N and TN by ER-HCW was 98 ± 2%, 85 ± 11%, 83 ± 15% and 73 ± 11%, respectively. Specifically, the ER enhances the interactions between pollutants and micro-organisms, consequently, the efficient removal of NH4 +[sbnd]N and TN has been achieved in ER-HCW. The TF has a positive effect in refreshing the wetland with fresh air to enhance the dissolved oxygen (DO) in the system. In case of AA, intermittent aeration is more effective than continuous aeration, as it facilitates the establishment of aerobic and anaerobic conditions suitable for nitrification and denitrification. Statistical analysis shows that DO, organic loading rate and specific surface area requirement are the most significant factors that influence the performance of intensified CWs. © 2017 Elsevier Ltd

Denjean B.,Beijing Forestry University | Denjean B.,Asia Center | Altamirano M.A.,Deltares | Graveline N.,Montpellier University | And 13 more authors.
Environmental Research | Year: 2017

This paper proposes a conceptual framework to systematize the use of Nature-based solutions (NBS) by integrating their resilience potential into Natural Assurance Scheme (NAS), focusing on insurance value as corner stone for both awareness-raising and valuation. As such one of its core goal is to align research and pilot projects with infrastructure development constraints and priorities. Under NAS, the integrated contribution of natural infrastructure to Disaster Risk Reduction is valued in the context of an identified growing need for climate robust infrastructure. The potential of NAS benefits and trade-off are explored by through the alternative lens of Disaster Resilience Enhancement (DRE). Such a system requires a joint effort of specific knowledge transfer from research groups and stakeholders to potential future NAS developers and investors. We therefore match the knowledge gaps with operational stages of the development of NAS from a project designer perspective. We start by highlighting the key role of the insurance industry in incentivizing and assessing disaster and slow onset resilience enhancement strategies. In parallel we place the public sector as potential kick-starters in DRE initiatives through the existing initiatives and constraints of infrastructure procurement. Under this perspective the paper explores the required alignment of Integrated Water resources planning and Public investment systems. Ultimately this will provide the possibility for both planners and investors to design no regret NBS and mixed Grey-Green infrastructures systems. As resources and constraints are widely different between infrastructure development contexts, the framework does not provide explicit methodological choices but presents current limits of knowledge and know-how. In conclusion the paper underlines the potential of NAS to ease the infrastructure gap in water globally by stressing the advantages of investment in the protection, enhancement and restoration of natural capital as an effective climate change adaptation investment. © 2017

Marin V.H.,University of Chile | Delgado L.E.,University of Chile | Tironi-Silva A.,Fundacion CTF | Finlayson C.M.,Charles Sturt University | Finlayson C.M.,Institute for Water Education
Wetlands | Year: 2017

Complexity is an accepted characteristic of social-ecological systems. However, its analysis has been mostly theoretical with few empirical studies. Complex systems share three features: radical openness (the system cannot be understood unless an extended, global, environment is considered), radical uncertainty (emergence and non-linearity make them impossible to be fully predictable) and contextuality (no unique way to know them). Social-ecological systems listed as important under international treaties, such as wetlands within the Ramsar Convention, share these features, which can be explored using case studies. In this article, we explore the complexities derived from the 2004 ecological change (i.e. the local collapse of an emblematic bird species) in the Carlos Anwandter Sanctuary, a Chilean coastal wetland, by means of two ten-year windows (scientific publications and Internet web pages). We based our analysis on the question: what is the state of knowledge, ten years after its ecological change? Results show many answers; science has several hypotheses with low testing possibilities. Still, civil society decided that only one (a forestry company guilty of producing the change) is valid. We discuss the role of international organizations when dealing with social-ecological conflicts and identify the conundrum that can develop in response to how these are handled. © 2017 Society of Wetland Scientists

Jain R.,Institute for Water Education | Jain R.,University Paris Est Creteil | Matassa S.,Institute for Water Education | Matassa S.,University of Cassino and Southern Lazio | And 4 more authors.
Environmental Science and Pollution Research | Year: 2015

Total selenium removal by the activated sludge process, where selenite is reduced to colloidal elemental selenium nanoparticles (BioSeNPs) that remain entrapped in the activated sludge flocs, was studied. Total selenium removal efficiencies with glucose as electron donor (2.0 g chemical oxygen demand (COD) L−1) at neutral pH and 30 °C gave 2.9 and 6.8 times higher removal efficiencies as compared to the electron donors lactate and acetate, respectively. Total selenium removal efficiencies of 79 (±3) and 86 (±1) % were achieved in shake flasks and fed batch reactors, respectively, at dissolved oxygen (DO) concentrations above 4.0 mg L−1 and 30 °C when fed with 172 mg L−1 (1 mM) Na2SeO3 and 2.0 g L−1 COD of glucose. Continuously operated reactors operating at neutral pH, 30 °C and a DO >3 mg L−1 removed 33.98 and 36.65 mg of total selenium per gram of total suspended solids (TSS) at TSS concentrations of 1.3 and 3.0 g L−1, respectively. However, selenite toxicity to the activated sludge led to failure of a continuously operating activated sludge reactor at the applied loading rates. This suggests that a higher hydraulic retention time (HRT) or different reactor configurations need to be applied for selenium-removing activated sludge processes. [Figure not available: see fulltext.] © 2015 Springer-Verlag Berlin Heidelberg

Liotta F.,University of Cassino and Southern Lazio | Chatellier P.,University Paris Est Creteil | Esposito G.,University of Cassino and Southern Lazio | Fabbricino M.,University of Naples Federico II | And 4 more authors.
Environmental Technology (United Kingdom) | Year: 2015

The role of total solids (TS) content in anaerobic digestion of selected complex organic matter, e.g. rice straw and food waste, was investigated. A range of TS from wet (4.5%) to dry (23%) was evaluated. A modified version of the Anaerobic Digestion Model No.1 for a complex organic substrate is proposed to take into account the effect of the TS content on anaerobic digestion. A linear function that correlates the kinetic constants of three specific processes (i.e. disintegration, acetate and propionate up-take) was included in the model. Results of biomethanation and volatile fatty acids production tests were used to calibrate the proposed model. Model simulations showed a good agreement between numerical and observed data. © 2014 Taylor and Francis.

Abdullah A.D.,Institute for Water Education | Abdullah A.D.,Technical University of Delft | Abdullah A.D.,University of Basrah | Gisen J.I.A.,Universiti Malaysia Pahang | And 7 more authors.
Hydrology and Earth System Sciences | Year: 2016

Longitudinal and vertical salinity measurements are used in this study to predict the extent of inland seawater intrusion in a deltaic river estuary. A predictive model is constructed to apply to the specific tidal, seasonal, and discharge variability and geometric characteristics of the Shatt al-Arab River (SAR) situated along the border of Iraq and Iran. Reliable hydrologic simulation of salinity dynamics and seawater intrusion was lacking prior to this study. Tidal excursion is simulated analytically using a 1-D analytical salt intrusion model with recently updated equations for tidal mixing. The model was applied under different river conditions to analyse the seasonal variability of salinity distribution during wet and dry periods near spring and neap tides between March 2014 and January 2015. A good fit is possible with this model between computed and observed salinity distribution. Estimating water abstractions along the estuary improves the performance of the equations, especially at low flows and with a well-calibrated dispersion-excursion relationship of the updated equations. Salt intrusion lengths given the current data varied from 38 to 65g km during the year of observation. With extremely low river discharge, which is highly likely there, we predict a much further distance of 92g km. These new predictions demonstrate that the SAR, already plagued with extreme salinity, may face deteriorating water quality levels in the near future, requiring prompt interventions. © 2016 The Author(s).

Bateganya N.L.,University of Natural Resources and Life Sciences, Vienna | Nakalanzi D.,Institute for Water Education | Babu M.,National Water and Sewerage Corporation | Hein T.,University of Natural Resources and Life Sciences, Vienna
Environmental Technology (United Kingdom) | Year: 2015

In many sub-Saharan Africa municipalities and cities, wastewater is discharged with limited or no treatment at all, thus creating public and environmental health risks. This study assessed the performance of a conventional municipal wastewater treatment plant (WWTP), based on effluent pollution flux, in Masaka Municipality, Uganda. Also, the downstream pollution attenuation through a natural wetland was analysed to ascertain its role in buffering the WWTP performance deficits. Generally, there was deficiency in WWTP performance, with 100% failure over a five-year assessment period, for example, the mean effluent biochemical oxygen demand (BOD)5 and chemical oxygen demand (COD) concentrations (mgl-1) were found to be 316 ± 15 and 582 ± 28 compared with 50 and 100 maximum permissible environment discharge limits, respectively. Despite these deficits in WWTP performance, the wetland buffer effectively reduced pollutant loads for suspended solids (73%), organic matter (BOD5, 88% and COD, 75%), nutrients (total nitrogen, 74% and total phosphorus, 83%) and pathogens (faecal coliforms, 99%). These findings underpin the challenge of managing municipal wastewater using centralized mechanical WWTPs in the region. However, the wetland buffer system demonstrated a critical role these ecosystems play in abating both pulse and intermittent pollution loads from urban environments of sub-Saharan Africa whose sanitation systems are defective and inadequate. Therefore, it was concluded that integrating wetland ecosystems in urban planning as natural landscape features to enhance municipal wastewater management and pollution control is paramount. © 2015 Taylor and Francis.

Crochemore L.,IRSTEA | Ramos M.-H.,IRSTEA | Pappppenberger F.,European Center for Medium Range Weather Forecasts | Van Andel S.J.,Institute for Water Education | Wood A.W.,U.S. National Center for Atmospheric Research
Bulletin of the American Meteorological Society | Year: 2016

A role-playing approach to better understand the challenges of using monthly probabilistic forecasts in sequential decision-making in water management. © 2016 American Meteorological Society.

Gersonius B.,Institute for Water Education | Ashley R.,Institute for Water Education | Pathirana A.,Institute for Water Education | Zevenbergen C.,Institute for Water Education | Zevenbergen C.,Technical University of Delft
Proceedings of the Institution of Civil Engineers: Engineering Sustainability | Year: 2010

An increasing lack of stationarity in environmental phenomena and hence in the predictability of loading and effects makes it necessary to modify the traditional approach for planning and risk assessment of flood mitigation. The traditional approach attempts to manage the flooding system with the use of predictive/optimisation methods. These use the 'most likely' or average future projection to identify a singular optimal adaptation strategy. Because the planning and risk management in this method is often decoupled from the dynamics and uncertainty of the flooding system, this is a rather risky approach. This paper argues that responsible climate adaptation requires an alternative approach that attempts to assess and manage the resiliency of the flooding system for long-term future change. The aim of such an approach is to keep the system within a configuration of states that gives at least acceptable functioning despite the occurrence of possible changes. The paper proposes an options planning and assessment process for managing the resiliency of the flooding system to climate change. This process explicitly acknowledges the uncertainty in future climate conditions by introducing and implementing flexibility (real options) into the designed components of the flooding system.

Ridolfi E.,University of Rome La Sapienza | Servili F.,University of Rome La Sapienza | Magini R.,University of Rome La Sapienza | Napolitano F.,University of Rome La Sapienza | And 2 more authors.
Procedia Engineering | Year: 2014

Pressure determination in water distribution systems (WDS) is important because it generally drives the operational actions for leakage and failure management, backwater intrusion and demand control. This determination would ideally be done through pressure monitoring at every junction in the distribution system. However, due to limited resources, it is only possible to monitor at a limited number of nodes. To this end, this work explores the use of an Artificial Neural Network (ANN) to estimate pressure distributions in a WDS using the available data at the monitoring nodes as inputs. The optimal subset of monitoring nodes are chosen through an entropy-based method. Finally, pressure values are compared to synthetic pressure measures estimated through a hydraulic model. © 2014 The Authors.

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