Delft, Netherlands
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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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