Integrated modelling of the influence of urbanization and climate change on river water quality

Climate change is one of the most important drivers modifying the hydrologic and environmental characteristics of natural catchments. When dealing with the quality of natural waters, these factors should be weighed up against anthropogenic factors that may increase or decrease the effect of climatic modifications. However, a detailed and more generalised analysis of such environmental impacts at a relatively small scale is currently lack. This paper aims to fill this gap. The use of a holistic approach is also required by the EU Water Framework Directive, which prescribes integrated analysis for river basin management in order to meet environmental and ecological objectives. In order to qua…

Valutazione dell’incertezza connessa con i modelli di qualità dei deflussi meteorici in ambiente urbano

Uncertainty of a biological nitrogen and phosphorus removal model

In the last few years, the use of mathematical models in wastewater treatment plant (WWTP) processes has become a common way to predict WWTP behaviour. However, mathematical models generally demand advanced input for their implementation that must be evaluated by an extensive data gathering campaign, which cannot always be carried out. This fact, together with the intrinsic complexity of the model structure, leads to model results that may be very uncertain. Quantification of the uncertainty is imperative. However, despite the importance of uncertainty quantification, only a few studies have been carried out in the wastewater treatment field, and those studies only included a few of the sou…

Integrated urban drainage uncertainty assessment : the influence of the likelihood efficiency measures

Integrated urban drainage uncertainty assessment : the influence of the likelihood efficiency measures

Towards a new protocol for field measurements of greenhouse gases from wastewater treatment plant

Emissions into the atmosphere of greenhouse gases (GHGs), i.e., carbon dioxide, methane and nitrous oxide from wastewater treatment plants are of increasing concern in the water industry. In order to produce useful and comparable information for monitoring, assessing and reporting GHG emissions from wastewater treatment plants, there is a crescent need for a general accepted methodology. This paper aims at proposing the first protocol for monitoring and accounting GHG emissions from wastewater treatment plants taking into account both direct and internal indirect emissions focusing on sections known to be major responsible of GHG emissions i.e. oxidation tanks and sludge digestion. The main…

Calcul des contributions des incertitudes dans un modèle complexe de qualité de l'eau

The quantification of uncertainty in integrated urban drainage water quality models is of paramount interest. Indeed, the assessment of the reliability of the model results for complex water quality models is useful for understanding the significance of the results. However, the state of knowledge regarding uncertainties in urban drainage models is poor. In the case of integrated urban drainage water quality models, due to the fact that integrated approaches are basically a cascade of sub-models (simulating sewer system, wastewater treatment plant and receiving water body), the uncertainty produced in one sub-model propagates to the following ones depending on the model structure, the estim…

Urban runoff quality modelling uncertainty assessment

Assessment of urban drainage environmental impact on receiving water bodies: Comparison between a detailed and a simplified integrated model.

Point and non-point pollution assessment for a receiving water body quality management

The effect of acceptability threshold over an integrated urban drainage model uncertainty.

Diffuse and concentrated pollution control at watershed-scale: an Italian case study

Sensitivity and uncertainty analysis of a plant-wide model for carbon and energy footprint of wastewater treatment plants

This paper presents the sensitivity and uncertainty analysis of a mathematical model for Greenhouse gas (GHG) and energy consumption assessment from wastewater treatment plants (WWTPs). The model is able to simultaneously describe the main biological and physical-chemical processes in a WWTP. Specifically, the mathematical model includes the main processes of the water and sludge lines influencing the methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) emissions. Further, the process energy demand and the energy recovery are also taken into account. The main objective of this paper is to analyze the key factors and sources of uncertainty influencing GHG emissions from WWTP at a pla…

Global sensitivity analysis in environmental water quality modelling: Where do we stand?

Global sensitivity analysis (GSA) is a valuable tool to support the use of mathematical models for environmental systems. During the last years the water quality modelling field has embraced the use of GSA. Environmental water quality modellers have tried to transfer the knowledge and experience acquired in other disciplines. The main objective of this paper is to provide an informed problem statement of the issues surrounding GSA applications in the environmental water quality modelling field. Specifically, this paper aims at identifying, for each GSA method, the potential use, the critical issues to be solved and the limits identified in a comprehensive literature review. The paper shows …

LE EMISSIONI DI GAS CLIMALTERANTI DAI SISTEMI MBR

La salvaguardia dell’ambiente pone ad oggi delle nuove sfide nei confronti dei cambiamenti climatici. Invero, il fenomeno del climate change, i cui principali effetti portano ad un innalzamento delle temperature a seguito del rilascio di emissioni di gas climalteranti (i.e., anidride carbonica, CO2; metano, CH4; protossido di azoto, N2O), richiede degli interventi a breve, medio e lungo termine per limitare i sempre più crescenti danni ambientali. Gli impianti di depurazione contribuiscono anch’essi al fenomeno del climate change attraverso le emissioni di gas climalteranti (Global Water Research Coalition – GWRC, 2011; Law et al., 2012; Zhan et al., 2017).

Valutazione dell’incertezza di un modello integrato di drenaggio urbano.

Valutazione dell’impatto sui corpi idrici delle acque di pioggia: confronto tra un modello integrato fisicamente basato e uno semplificato

Nella nota viene presentato il confronto tra un modello complesso e uno semplificato, entrambi utilizzabili per la simulazione di un sistema integrato di drenaggio urbano

Towards a Reduction of Greenhouse Gases: a New Decision Support System for Design, Management and Operation of Wastewater Treatment Plants

The increasing attention for the environment has led to reduce the emissions from wastewater treatment plants (WWTPs). Moreover, the increasing interest towards the greenhouse gas (GHG) emissions from WWTPs suggests to reconsider the traditional tools used for designing and managing WWTPs. Indeed, nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) can be emitted from wastewater treatment significantly contributing to the greenhouse gas (GHG) footprint. The reduction of energy consumption as well as GHG emission are of particular concern for large WWTPs which treat the majority of wastewater in terms of both volume and pollution load. Nowadays, there is an increasing need to develop…

A moving bed membrane bioreactor pilot plant for carbon and nutrient removal

The paper reports the main results of an experimental gathering campaign carried out on a moving bed membrane bioreactor pilot plant conceived for carbon and nutrients removal according to a University of Cape Town scheme. Organic carbon, nitrogen and phosphorus removal, biokinetic/stoichiometric constants, membrane fouling tendency and sludge dewaterability have been assessed during experiments. The achieved results showed that pilot plant was able to guarantee very high carbon removal, with average efficiency of 98%. In terms of nitrification, the system showed an excellent performance, with efficiencies higher than 98% for most of the experiments. This result might be related to the pres…

Greenhouse gas emissions from membrane bioreactors: analysis of a two-year survey on MBRs

The study aims at evaluating the nitrous oxide (N2O) emission from membrane bioreactors (MBRs) for wastewater treatment. With this regards two-years of experimental activities were performed. More specifically, the study investigates the N2O emissions considering multiple influential factors: i. configurations (i.e., sequential batch- SB-MBR; pre-denitrification - DN-MBR; University Cape Town, UCT-MBR and UCT moving bed biofilm reactor, UCT-MB-MBR); ii. wastewater composition (municipal or industrial); iii. Plant operational conditions (i.e., sludge retention time, SRT, carbon-to-nitrogen ratio, C/N, hydraulic retention time, HRT); iv. and membrane modules. Among the overall analysed config…

The beneficial effect of local rain water reuse in urban areas: a long term modelling approach

Uncertainty in environmental and hydrological mathematical modelling

The current state of knowledge regarding uncertainties in urban drainage models is poor. This is in part due to the lack of clarity in the way model uncertainty analyses are conducted and how the results are presented and used. There is a need for a common terminology and a conceptual framework for describing and estimating uncertainties in urban drainage models. Practical tools for the assessment of model uncertainties for a range of urban drainage models are also required to be developed. This paper, produced by the International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, is a contribution to the development of a harmonised framewor…

A new integrated MBR model for wastewater treatment: sensitivity and uncertainty analysis

In this study a new integrated membrane bioreactor (MBR) model is proposed. The model is able to describe the main biological processes aimed at the carbon and the nutrients (nitrogen, N and phosphorus, P) removal coupled with the soluble microbial products (SMP) formation/degradation. Furthermore, the model describes the key physical processes and the interconnection between SMP and membrane fouling. The model was calibrated by adopting data measured during the monitoring of a University Cape Town (UCT) MBR pilot plant. A sensitivity analysis allowed the reduction of the number of model FACTORs to be calibrated from 122 to 45. A good correlation between measured and simulated data was obta…

The GSA-GLUE approach for uncertainty assessment of an integrated MBR model

In the recent literature, the uncertainty of wastewater treatment plant (WWTP) modelling has had relevant interest both for designers and operators. Indeed, the frequent data lacking and the need to improve process knowledge, in case of innovative technologies, make the use of mathematical models more uncertain. Therefore, the need to make model uncertainty more explicit is warmly recommended. However, only few applications of uncertainty analysis in the wastewater field have been carried out. In this work, the combination of the global sensitivity analysis (GSA) and the Generalized Likelihood Uncertainty Estimation (GLUE) is applied for the uncertainty assessment of a WWTP model, in order …

Uncertainty estimation of a complex water quality model: GLUE vs Bayesian approach applied with Box – Cox transformation

In urban drainage modelling, uncertainty analysis is of undoubted necessity; however, several methodological aspects need to be clarified and deserve to be investigated in the future, especially in water quality modelling. The use of the Bayesian approach to uncertainty analysis has been stimulated by its rigorous theoretical framework and by the possibility of evaluating the impact of new knowledge on the modelling estimates. Nevertheless, the Bayesian approach relies on some restrictive hypotheses that are not present in less formal methods like GLUE. One crucial point in the application of Bayesian methods is the formulation of a likelihood function that is conditioned by the hypotheses …

Infiltration facilities design: comparison between simplified approaches and detailed physically based modelling

Modelling urban stormwater impact mitigation by using bmps and storage tanks

The continuous growth of urban areas and the increasing public awareness about environmental impact of stormwater raised high interest on quality impact on the receiving water bodies. Indeed, in the last decades, large efforts have been provided for improving urban drainage systems in order to mitigate environmental impacts. In the present paper, a simplified modelling approach has been developed in order to evaluate the mitigation efficiency of different BMP schemes including infiltration and storage facilities and both considering possible distributed controls and centralised structures. The main goals of the research are the simulation of BMP efficiency in different operational condition…

Polyhydroxyalkanoates from mixed microbial culture: Production and extraction through green methods

Large scale polyhydroxyalkanoates (PHA) production is limited by high production costs compared to that of petroleum-based plastics. Two key factors can be pin down to reduce costs: i) the use of mixed microbial cultures (MMC) instead of pure cultures and ii) the application of cheap and environmental friendly recovery technologies. In this work, the MMC biomass with PHA-accumulating capacity was selected in a sequencing batch reactor fed with a synthetic effluent emulating a fermented oil mill wastewater. The biomass was harvested and transferred to an accumulation reactor, where PHA contents up to 54% of the dry cell weight were obtained, using a mixture of acetic and propionic acids. A c…

Évaluation du colmatage de tranchées d'infiltration selon le type de sol : analyse à long terme

In recent years, limitations linked to traditional urban drainage schemes have been pointed out and new approaches were developed introducing more natural methods for retaining and/or disposing of stormwater. Such practices include infiltration and storage tanks in order to reduce the peak flow and retain part of the polluting components. The impact of such practices on stormwater quantity and quality is not easily assessable because of the complexity of physical and chemical processes involved. In such cases, integrated urban drainage models may play a relevant role providing tools for long term analysis of infiltration structures efficiency. In this study, the effect of the clogging pheno…

Uncertainty propagation throughout an integrated water-quality model

In integrated urban drainage water quality models, due to the fact that integrated approaches are basically a cascade of sub-models (simulating sewer system, wastewater treatment plant and receiving water body), uncertainty produced in one sub-model propagates to the following ones depending on the model structure, the estimation of parameters and the availability and uncertainty of measurements in the different parts of the system. Uncertainty basically propagates throughout a chain of models in which simulation output from upstream models is transferred to the downstream ones as input. The overall uncertainty can differ from the simple sum of uncertainties generated in each sub-model, dep…

Modellazione dell’impatto dei deflussi urbani sui corpi idrici ricettori attraverso un approccio integrato

Towards a reduction of greenhouse gas emission from wastewater treatment plants: a new plant wide experimental and modelling approach

The increasing interest in greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs) has led to the development of new tools for their design and management. Studies about gas emissions show that the sewer collection and the wastewater treatment plant are anthropogenic GHG potential sources, so they contribute to the climate change and air pollution. A wastewater treatment plant receives wastewater from sewers and, while produces treated water for discharge into surface water, emits the three major greenhouse gases, CO2, CH4, and N2O, during the treatment processes, and additional amounts of CO2 and CH4 from the energy demands (Bani Shahabadi et al., 2009). Indeed, energy cons…

Integrated Urban Water Modeling with Uncertainty Analysis

In the last 20th years, the scientific world has got particular care towards the problems that involve the respect of the environment. According to this point, several researches were developed to describe the phenomena that take place during both wet and dry period and to increase the knowledge in this field. In particular, the attention was addressed towards the problems linked with the pollution of the water body because of the pollution carried by rainfall waters in the urban environment. In order to obtain a good description of the problem, it is important, of course, to analyze both quantity and quality aspects connected with all the transformation phases that characterize the urban w…

Water quality monitoring campaign design based on integrated modelling identifiability analysis.

Modèles intégrés par drainage urbain : propagation d'incertitude et identifiabilité de paramètres

Colloque avec actes et comité de lecture. Internationale.; International audience

Greenhouse gas from moving bed based integrated fixed film activated sludge membrane bioreactors

The present paper reports the results of a nitrous oxide production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the UCT layout for biological phosphorous removal. Samples of gas and liquid were collected in order to measure the gaseous, as well as the dissolved concentration of N2O. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated. The results confirmed that the anoxic reactor represents the main source of nitrous oxide production. A significant production of N2O was, however, also found in the anaerobic reactor, thus indicating a probable occur…

II ADVANCED COURSE Innovative wastewater treatment and mathematical modeling

Over the past years, the knowledge and understanding of biological wastewater treatment has advanced extensively and moved away from empirically-based approaches to a fundamentally-based 'first principles' approach that embrace: bio-chemistry, microbiology, mathematics, and physical, chemical and bioprocess engineering. Also, the wastewater treatment plant of the future will be a water resource recovery facility (WRRF), implying attention for quite different aspects of these large scale technologies. Many of these advances have matured to a degree that they have been codified into mathematical models able to describe and simulate diverse systems under different environmental conditions at e…

BioMAc 2016 Bioreattori a membrane (MBR) e trattamenti avanzati per la depurazione delle acque

Questo volume raccoglie i contributi presentati nella manifestazione BioMAc 2016: Bioreattori a Membrane (MBR) e trattamenti avanzati per la depurazione delle Acque, che ha avuto luogo presso il Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali dell'Università degli Studi di Palermo, Aula G. Capitò, nei giorni 27 e 28 ottobre 2016.