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11th IFAC Symposium on Dynamics and Control of Process SystemsIncluding Biosystems DYCOPS-CAB 2016 — Trondheim, Norway, 6—8 June 2016 ; The determination of diffusivity of compounds that can be transferred from packaging into food products is a keystone to ensure consumer's safety. However, no clear guidelines exist as how the diffusion experiment should be designed in order to maximise the accuracy of the estimated parameter. With the perspective of optimal experimental design, a methodology to estimate the diffusivity of a migrating compound in a polymer is presented, both for global methods (that measure the overall concentration) and local methods (that measure the profile of concentration along the polymer thickness). To demonstrate the methodology, real experimental data (transfer of Uvitex OB from linear low-density polyethylene) are used, and the OED based methodology is benchmarked against other heuristics. It is seen that, although the OED methodology outperforms the rest of methodologies when good initial guesses are available, its performance becomes deteriorated when gross over- or underestimations of the true value are made ; The author would like to acknowledge the reviewers for very constructive comments that have contributed to improve this work. This work is funded by the People Program (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013 under REA agreement 627475 (GREENCOST). The author belongs to the Galician Competitive Research Group GRC 2013-032, programme cofunded by FEDER ; SI

Waste Water Treatment Plants (WWTPs) account for more than 1% of consumption of electricity in Europe, one of the largest shares of energy use among public industries. The aim of ENERWATER is to provide measuring tools to quantify the energy consumption of WWTPs and to elaborate the standards to compare and ultimately optimise the operation of WWTPs. The methodology is demonstrated on 50 WTTPs, whose energy consumption is thoroughly monitored. ENERWATER goals will be reached by i) defining the concept of energy efficiency in WWTP and the performance indicators suitable for its quantification; ii) standardising the methods for measuring energy consumption in order to ensure that comparable figures are obtained; iii) using data treatment tools to not only quantify but also diagnose the reasons for energy inefficiency and iv) proposing a global index that measures the energy efficiency of a WWTP. All these steps will eventually be part of a general methodology that can be the draft of a standard for measuring energy efficiency in WWTP. ENERWATER is a three-year activity that involves 9 partners (universities and companies) from 4 European countries (Germany, Italy, Spain and the United Kingdom). To ensure a fast transfer of results to the relevant actors, ENERWATER puts in contact research groups, SMEs, utilities, city councils, policy makers and industry beyond the project consortium. These actions should bring European Water Industry a competitive advantage in new products development and a faster access to markets by facilitating evidence of energy reduction, thereby fostering adoption on new technologies. ; This project is carried out with financial support from the H2020 Coordinated Support Action ENERWATER (grant agreement number 649819): www.enerwater.eu. Although the project's information is considered accurate, no responsibility will be accepted for any subsequent use thereof. The European Community accepts no responsibility or liability whatsoever with regard to the presented material, and the work hereby ...

© 2018. This is the accepted manuscript of the following article: Longo, S., Hospido, A., Lema, J., & Mauricio-Iglesias, M. (2018). A systematic methodology for the robust quantification of energy efficiency at wastewater treatment plants featuring Data Envelopment Analysis. Water Research, 141, 317-328. doi:10.1016/j.watres.2018.04.067 ; This article examines the potential benefits of using Data Envelopment Analysis (DEA) for conducting energy-efficiency assessment of wastewater treatment plants (WWTPs). WWTPs are characteristically heterogeneous (in size, technology, climate, function .) which limits the correct application of DEA. This paper proposes and describes the Robust Energy Efficiency DEA (REED) in its various stages, a systematic state-of-the-art methodology aimed at including exogenous variables in nonparametric frontier models and especially designed for WWTP operation. In particular, the methodology systematizes the modelling process by presenting an integrated framework for selecting the correct variables and appropriate models, possibly tackling the effect of exogenous factors. As a result, the application of REED improves the quality of the efficiency estimates and hence the significance of benchmarking. For the reader's convenience, this article is presented as a step-by-step guideline to guide the user in the determination of WWTPs energy efficiency from beginning to end. The application and benefits of the developed methodology are demonstrated by a case study related to the comparison of the energy efficiency of a set of 399 WWTPs operating in different countries and under heterogeneous environmental conditions ; The authors belong to the Galician Competitive Research GroupGRC2013-032 and the CRETUS strategic partnership (AGRUP2015/02), co-funded by FEDER (EU). Besides, they are supported by 'ENERWATER' Coordination Support Action that has received founding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 649819 ; SI

This is a post-print version of the article ; Biotransformation of most organic micropollutants (OMPs) during wastewater treatment is not complete and a drastic decrease of the biotransformation rate with time is reported for many OMPs in different biological processes. To minimize and accurately predict the emission of OMPs into the environment, the mechanisms and limitations behind their biotransformations should be clarified. Aiming to achieve this objective, the present study follows a mechanistic modelling approach, based on the formulation of four models according to different biotransformation hypotheses: Michaelis-Menten kinetics, chemical equilibrium between the parent compound and the transformation product (TP), enzymatic inhibition by the TP, and a limited compound bioavailability due to its sequestration in the solid phase. These models were calibrated and validated with kinetic experiments performed in two different anaerobic systems: continuous reactors enriched with methanogenic biomass and batch assays with anaerobic sludge. Model selection was conducted according to model suitability criteria (goodness of fitting the experimental data, confidence of the estimated parameters, and model parsimony) but also considering mechanistic evidences. The findings suggest that reversibility of the biological reactions and/or sequestration of compounds are likely the causes preventing the complete biotransformation of OMPs, and biotransformation is probably limited by thermodynamics rather than by kinetics. Taking into account its simplicity and broader applicability spectrum, the reversible biotransformation is the proposed model to explain the incomplete biotransformation of OMPs ; This research was funded by the Spanish Government (AEI) through the COMETT project (CTQ2016-80847-R) and by an FPU Grant (FPU13/01255). The authors belong to CRETUS Strategic Partnership (AGRUP2015/02) and to Galician Competitive Research Group (GRC ED431C 2017/29). All these programs are co-funded by FEDER (EU) ; SI

This investigation studies the impact of trace elements supplementation on protein anaerobic conversion into volatile fatty acids (VFAs). Two continuous reactors were operated with two model substrates, casein and gelatin, at acid (pH 5) and neutral (pH 7) conditions, with the addition of macro and micronutrients. Micronutrients increased the acidification degree of both proteins from 40% to 50% to more than 60% only at pH 7, which was consistent with a greater amino acid consumption at neutral conditions. Furthermore, trace elements modified the process selectivity, promoting valeric acids production and other variations dependant on protein composition. Isomerisation and chain elongation processes were identified as a consequence of the observed deviations between amino acid consumption and VFA production. Overall, this study demonstrated that the supplementation of micronutrients can be useful to enhance and steer the anaerobic fermentation of protein-rich streams ; This project has received funding from the Spanish Government through the European Union's ERA-IB programme under grant agreement number PCIN-2016-102 and from the Spanish Ministry of Education (FPU14/05457). The authors belong to a Galician Competitive Research Group (ED431C2017/029; ED431E 2018/01), co-funded by Xunta de Galicia (Spain) and the European Regional Development Fund (ERDF-EU) ; SI

This study focuses on verifying the occurrence of elongation processes during protein mixed culture fermentation, without the supplementation of electron donor compounds. During casein mixed-culture fermentation at pH 5, it was observed that longer chain volatile fatty acid production increased, which could not be justified by the associated amino acid consumption. Consequently, the occurrence of chain elongation processes was hypothesized. To verify this hypothesis, three casein batch tests, with and without acetic acid initial supplementation, were performed at pH 5. The results suggest that acetic and propionic acids are indeed consumed to selectively generate n-valeric acid through the coupling with electron donor amino acids, whose consumption was further verified through the amino acid analysis. Prolonged simultaneous availability of suitable amino acids and short chain volatile fatty acids and an acid equivalent concentration threshold were identified as key parameters for the occurrence of chain elongation. The supplementation of acetic acid at the beginning of the test changed the selectivity of the elongation process, promoting n-butyric and iso-valeric production. The associated mechanisms were preliminary conceptualized, constituting a first step for further studies on the subject. To the best of our knowledge, this is the first study demonstrating the feasibility of chain elongation processes during protein mixed culture fermentation without electron donor supplementation ; This project has received funding from the Spanish Government through BIOCHEM project (PCIN-2016-102, ERA-IB-2 7th call, ERA-IB-16-052) ; SI

This is a post-print version of the published article: Gonzalez-Gil, L., Mauricio-Iglesias, M., Serrano, D., Lema, J. M., & Carballa, M. (2018). Role of methanogenesis on the biotransformation of organic micropollutants during anaerobic digestion. Science of The Total Environment, 622, 459-466. https://doi.org/10.1016/j.scitotenv.2017.12.004 ; Several studies showed that some organic micropollutants (OMPs) are biotransformed during anaerobic digestion (AD). Yet, most of them aim at reporting removal efficiencies instead of understanding the biotransformation process. Indeed, how each of the main AD stages (i.e., hydrolysis, acidogenesis, and methanogenesis) contribute to OMP biotransformation remains unknown. This study focuses on investigating the role of methanogenesis, the most characteristic step of AD, to OMP removal. More specifically, the sorption and the biotransformation of 20 OMPs by methanogenic biomass were analyzed determining their concentrations in both liquid and solid phases. Sorption onto methanogenic biomass displayed a similar behavior as reported for digested sludge. Most of the OMPs were biotransformed to a medium extent (35–70%) and only sulfamethoxazole was completely removed. Comparing these results with those reported for the complete AD process, methanogenesis was proven to play a key role, accounting for more than 50% of the OMP biotransformation (except for roxithromycin) during AD. An increase in the organic loading rate from 1 to 2 g COD/L d, typical loads employed in sewage sludge anaerobic digesters, did not exert a clear cometabolic effect on the OMPs biotransformation. It is hypothesized that biotransformation occurs in both liquid and solid phases because no link between the partition coefficient (Kd) and the overall biotransformation efficiency was found. These findings allow a better understanding of the OMPs fate under anaerobic conditions, which is necessary to design efficient biological mitigation strategies ; This research was funded by the Spanish Government (AEI) ...

The goal of this paper is to review and critically assess different methods to monitor key process variables for ethanol production from lignocellulosic biomass. Because cellulose-based biofuels cannot yet compete with noncellulosic biofuels, process control and optimization are of importance to lower the production costs. This study reviews different monitoring schemes, to indicate what the added value of real-time monitoring is for process control. Furthermore, a comparison is made on different monitoring techniques to measure the off-gas, the concentrations of dissolved components in the inlet to the process, the concentrations of dissolved components in the reactor, and the biomass concentration. Finally, soft sensor techniques and available models are discussed, to give an overview of modeling techniques that analyze data, with the aim of coupling the soft sensor predictions to the control and optimization of cellulose to ethanol fermentation. The paper ends with a discussion of future needs and developments ; This work was partially financed by the European Regional Development Fund (ERDF) and Region Zealand (Denmark) through the BIOPRO-SMV project. Furthermore, the work received funding from Innovation Fund Denmark (BIOPRO2 strategic research center, project number 4105-00020B). This project has also been supported partially by the EUDP project 'Demonstration of 2G ethanol in full scale, MEC' (Jr. no. 64015–0642). Finally, we wish to acknowledge the support obtained from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement number 713683 (COFUNDfellowsDTU) and from the Danish Council for Independent Research in the frame of the DFF FTP research project GREENLOGIC (grant agreement number 7017-00175A). Miguel Mauricio-Iglesias belongs to the Galician Competitive Research Group GRC2013-032 and the CRETUS strategic partnership (AGRUP2015/02), co-funded by FEDER (EU) ; SI

Operating lignocellulosic fermentation processes to produce fuels and chemicals is challenging due to the inherent complexity and variability of the fermentation media. Real‐time monitoring is necessary to compensate for these challenges, but the traditional process monitoring methods fail to deliver actionable information that can be used to implement advanced control strategies. In this study, a hybrid‐modeling approach is presented to monitor cellulose‐to‐ethanol (EtOH) fermentations in real‐time. The hybrid approach uses a continuous‐discrete extended Kalman filter to reconciliate the predictions of a data‐driven model and a kinetic model and to estimate the concentration of glucose (Glu), xylose (Xyl), and EtOH. The data‐driven model is based on partial least squares (PLS) regression and predicts in real‐time the concentration of Glu, Xyl, and EtOH from spectra collected with attenuated total reflectance mid‐infrared spectroscopy. The estimations made by the hybrid approach, the data‐driven models and the internal model were compared in two validation experiments showing that the hybrid model significantly outperformed the PLS and improved the predictions of the internal model. Furthermore, the hybrid model delivered consistent estimates even when disturbances in the measurements occurred, demonstrating the robustness of the method. The consistency of the proposed hybrid model opens the doors towards the implementation of advanced feedback control schemes ; This project has been partially supported by the Energy Technology Development and Demonstration Program in the frame of the project "Demonstration of 2G ethanol production in full scale" (Grant Number 64015‐0642), and has been realized together with Maabjerg Energy Center. The support of the BIOPRO2 Strategic Research Center (Grant Agreement No. 4105‐00020B) is gratefully acknowledged. The authors wish to acknowledge the support provided by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska‐Curie Grant Agreement ...

This paper describes the first methodology specifically tailored to estimate energy efficiency at wastewater treatment plants (WWTPs). Inspired by the cycle of continuous improvement, the method (i) precisely defines the concept of energy efficiency in WWTPs, (ii) proposes systematic and comparable ways to measure it, and (iii) allows benchmarking and diagnosing energy hotspots. The methodology delivers an aggregated measure of the WWTP energy efficiency defined as the Water Treatment Energy Index, a single energy label that uses universally known illustrations enabling wide communication of standardized information on the WWTP energy status. The accuracy, reproducibility and generality of the methodology were validated by a widespread energy benchmarking method, and a case study is presented to show its capabilities. By promoting dialogue towards the creation of a specific European Standard, the actions accomplished by the H2020 Coordination Support Action ENERWATER should positively contribute to improving the exchange of information on energy saving actions and results between wastewater utilities and towards other stakeholders ; We thank Benedetto Mirko d'Antoni and Diego Cingolani for their contribution to the development of the ENERWATER methodology. Stefano Longo, Miguel Mauricio-Iglesias and Almudena Hospido belong to the Galician Competitive Research Group (ED431C 2017/029) and the CRETUS strategic partnership (AGRUP2017/01), co-funded by FEDER (EU). Besides, they are supported by ENERWATER Coordination Support Action (www.enerwater.eu) that has received founding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 649819 ; SI

In response to strong growth in energy intensive wastewater treatment, public agencies and industry began to explore and implement measures to ensure achievement of the targets indicated in the 2020 Climate and Energy Package. However, in the absence of fundamental and globally recognized approach evaluating wastewater treatment plant (WWTP) energy performance, these policies could be economically wasteful. This paper gives an overview of the literature of WWTP energy-use performance and of the state of the art methods for energy benchmarking. The literature review revealed three main benchmarking approaches: normalization, statistical techniques and programming techniques, and advantages and disadvantages were identified for each one. While these methods can be used for comparison, the diagnosis of the energy performance remains an unsolved issue. Besides, a large dataset of WWTP energy consumption data, together with the methods for synthesizing the information, are presented and discussed. It was found that no single key performance indicators (KPIs) used to characterize the energy performance could be used universally. The assessment of a large data sample provided some evidence about the effect of the plant size, dilution factor and flowrate. The technology choice, plant layout and country of location were seen as important elements that contributed to the large variability observed ; This project is carried out with financial support from the H2020 Coordinated Support Action ENERWATER (grant agreement number 649819): www.enerwater.eu. Although the project's information is considered accurate, no responsibility will be accepted for any subsequent use thereof. The European Community accepts no responsibility or liability whatsoever with regard to the presented material, and the work hereby presented does not anticipate the Commission's future policy in this area. M.M.I. gratefully acknowledges the financial support provided by the People Program (Marie Curie Actions) of the European Union's Seventh Framework ...