Designing generic technologies in Energy Research: learning from two CEA technologies for double unknown management

International audienceThe aim of this paper is to shed light on an innovative strategy for the design of generic technologies (GTs). Research on radical innovation management, while recognizing the success of GTs, generally describes their design according to evolutionary strategies featuring multiple and uncertain trials, which would finally result in the discovery of common features between multiple applications. Building on a case study conducted on two technological development programs at the French Alternative Energies and Atomic Energy Commission (CEA), we exhibit an anomaly to this rarely discussed idea: we describe an alternative strategy that consists in intentionally designing common features that bridge the gap between a priori heterogeneous applications and a priori heterogeneous technologies. This anomaly brings three main results: 1) The usual trial-and-learning strategy is not necessarily the only strategy to design a GT; 2) beyond technological breakthrough, the value of GTs also relies on the capacity to reuse and connect existing technologies; 3) the design of GT might require sophisticated organizational patterns to be able to involve multiple technology suppliers and applications' providers

Life Cycle Assessment in the Circular Economy Transition. Case study: recycling in membrane technology

La Osmosis Inversa (OI) es la tecnología más extendida para la desalinización. OI es una tecnología de membrana. No obstante, esta tecnología tiene algunos problemas ambientales, como el uso de energía, la eliminación de salmuera y la generación de módulos de membrana de ósmosis inversa al final de su vida útil. Por ello, se ha investigado en el desarrollo de soluciones técnicas. Entre otros, cabe destacar los esfuerzos en la transición hacia la circularidad de esta tecnología a través de la innovación en alternativas de reciclaje. Las novedades de estos últimos años provienen de novedosos resultados a escala piloto de reciclado en nanofiltración (NF) y ultrafiltración (UF), y la segunda generación de reciclado indirecto que incluye el reciclado en osmosis directa (OD), que ha sido probado a escala de laboratorio. No obstante, existe una brecha de conocimiento sobre las implicaciones ambientales y económicas de estas tecnologías. La presente tesis tiene como objetivo actualizar y completar la comprensión del reciclaje directo en NF, UF y OD. Para garantizar la protección del medio ambiente y prevenir el impacto de la transición a la Economía Circular y alineada con la Directiva Marco de Residuos (2008/98/CE), se ha señalado como herramienta más adecuada la aplicación del Análisis de Ciclo de Vida (ACV). Por lo tanto, la presente tesis aplica el ACV y otras evaluaciones económicas a diferentes avances en la investigación del reciclaje OI al final de la vida útil. Eso es, la selección de pilotos de reciclaje, la integración de la variabilidad de los residuos, la definición y análisis de la cadena de suministro y una evaluación holística con una perspectiva de ciclo de vida del reciclaje en NF y OD. Además, se realizó una primera evaluación del reciclaje emergente en OD. En cuanto a las novedades metodológicas, cabe destacar el desarrollo de indicadores basados en resultados de ACV para salvar los vacios de datos y la incertidumbre de las tecnologías con bajos niveles de madureza tecnológica. Los resultados muestran que las tres tecnologías de reciclaje, reciclaje directo en NF y UF; y el reciclaje indirecto en OD tienen un impacto potencial bajo en el medio ambiente. Además, en la mayoría de los casos, se ha identificado que tienen un impacto menor que sus homologos comerciales. No obstante, los puntos críticos y otras barreras tecnológicas podrían complicar los ahorros ambientales potenciales del reciclaje. Es por ello que se han identificado los puntos donde aún se necesita algo de investigación o definición del proceso como en el caso de la caracterización de los módulos de OI desechados. Finalmente, la presente tesis define los criterios, indicadores y metodologías para continuar la investigación y el desarrollo mejorando la protección ambiental y la viabilidad económica de las tecnologías aquí estudiadas

A comprehensive review of hybrid forward osmosis systems: Performance, applications and future prospects

© 2015 Elsevier B.V. Forward osmosis (FO) has been increasingly studied in the past decade for its potential as an emerging low-energy water and wastewater treatment process. However, the term "low-energy" may only be suitable for those applications in where no further treatment of the draw solution (DS) is required either in the form of pretreatment or post-treatment to the FO process (e.g. where the diluted DS is the targeted final product which can be used directly or simply discarded). In most applications, FO has to be coupled with another separation process in a so-called hybrid FO system to either separate the DS from the final product water or to be used as an advanced pre-treatment process to conventional desalination technologies. The additional process increases the capital cost as well as the energy demand of the overall system which is one of the several challenges that hybrid FO systems need to overcome to compete with other separation technologies. Yet, there are some applications where hybrid FO systems can outperform conventional processes and this study aims to provide a comprehensive review on the current state of hybrid FO systems. The recent development and performance of hybrid FO systems in different applications have been reported. This review also highlights the future research directions for the current hybrid FO systems to achieve successful implementation

Sewage Polluted Water Treatment via Chitosan: A Review

Due to the increasing scarcity of water, wastewater treatment and water conditioning are one of the major future issues. Together with the need to apply highly accessible abundant materials and the demand to replace fossil-based chemicals with sustainable compounds from renewable resources, chitosan (CS) provides some of the solutions to obtain these goals and combines both, abundance and sustainability. Hence, the focus of this review is on the application of CS in wastewater treatment providing advantages and drawbacks in using CS in contrast to chitin. We herewith present the application of CS for coagulation/flocculation purposes, whether as native compound, as functionalized molecule or as blend, respectively, composite. The heavy metal, respectively, dye removal is an additional theme to be addressed in the body of the text. The third topic of this review contains the application of CS blends or composites in order to prepare membrane materials for water purification or conditioning. Together with a summary of the recent study, we discuss these findings and possible consequences for future works. In addition, we provide some theoretical background of the processes that CS is involved in and state some mechanistic insights

Advancing Anaerobic Membrane Bioreactors for Low Temperature Domestic Wastewater Treatment

Anaerobic membrane bioreactors (AnMBRs) use anaerobic microorganisms to convert organic compounds present in waste streams to biogas, a renewable energy source. They employ a membrane to remove suspended solids from treated wastewater and ensure excellent effluent quality, which allows for water reuse. The promise of treating wastewater while producing energy and water has increased interest in AnMBRs. The domestic wastewater temperature in temperate climates is often below 20°C, with lows around 5°C. Operation at these temperatures raises economic and environmental concerns associated with membrane fouling and the loss of methane through the effluent. This dissertation research developed and evaluated novel AnMBR designs to address these concerns and advance sustainable domestic wastewater treatment. First, we examined patents to achieve a deeper understanding of the AnMBR innovation landscape and its technological direction. We additionally aimed to determine if environmental concerns are being addressed by the field. Our review showed that only a fraction of AnMBR inventions address membrane fouling and methane loss mitigation, two impediments to sustainable AnMBR operation as concluded by previous life cycle assessment studies. We then evaluated methods focused on monitoring direct interspecies electron transfer (DIET) in anaerobic digesters. DIET has been suggested to enhance anaerobic digestion and we considered promoting DIET in biofilms in our novel AnMBR designs. Recent research has shown that DIET alone does not always explain observed performance enhancements. Our review indicated that a combination of methods is necessary to confirm the occurrence and expand our knowledge of DIET. Finally, we present the design and evaluation of two novel AnMBRs: the biofilm-enhanced AnMBR (BfE-AnMBR) and the MagnaTree reactor. The bioreactor of the BfE-AnMBR is separated into three compartments using two conductive meshes to support biofilm growth and DIET. The flow in the bioreactor is regularly reversed to avoid clogging of the meshes while allowing for substrate staging and partial biomass migration between the different compartments. The bioreactor is connected to an energy efficient membrane filtration unit containing a rotating ceramic disc. The BfE-AnMBR was operated at 15°C for approximately nine months, but the anticipated substrate staging was not accomplished. The concentration of organic compounds in domestic wastewater was likely too low to achieve localized bioreactor souring. Given these unanticipated outcomes and the complexity of BfE-AnMBR design and operation, its operation was discontinued. Subsequently, a second design, the MagnaTree reactor, which primarily relies on biofilm treatment, was evaluated. Biofilm growth in the MagnaTree reactor is accomplished through biofilm development on a tree-like structure, which contains branches with openings wrapped with meshes. Similar to the BfE-AnMBR, the MagnaTree contains conductive meshes to promote DIET. Influent wastewater and biomass mixed liquor are continuously recirculated through one set of meshes to maximize biofilm treatment, while another set of meshes provides filtration for permeate production. The MagnaTree reactor achieved 86% chemical oxygen demand removal after a startup of three months at 21°C. Future work with the MagnaTree reactor will determine its performance limits at lower temperatures. In conclusion, our work with the MagnaTree reactor confirms that biofilms can harness sufficient microbial activity to achieve adequate anaerobic treatment of domestic wastewater at 21°C. Future research is necessary to confirm if fouling and dissolved methane mitigation concerns with the MagnaTree reactor are sufficiently addressed to ensure domestic wastewater treatment with net positive energy and net greenhouse gas emission reductions.PHDEnvironmental EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/153352/1/steendam_1.pd

Mathematical and optimization modelling in desalination: State-of-the-art and future direction

The growing water demand across the world necessitates the need for new and improved processes as well as for a better understanding of existing processes. This level of understanding includes predicting system performance in scenarios that cannot always be evaluated experimentally. Mathematical modelling is a crucial component of designing new and improved engineering processes. Through mathematically modelling real life systems, we gain a deeper understanding of processes while being able to predict performance more effectively. Advances in computational capacity and the ease of assessing systems allow researchers to study the feasibility of various systems. Mathematical modelling studies enable optimization performance parameters while minimizing energy requirements and, as such, have been an active area of research in desalination. In this review, the most recent developments in mathematical and optimization modelling in desalination are discussed with respect to transport phenomena, energy consumption, fouling predictions, and the integration of multiple scaling evolution on heat transfer surfaces has been reviewed. Similarly, developments in optimization of novel reverse osmosis (RO) configurations have been analyzed from an energy consumption perspective. Transport models for membrane-based desalination processes, including relatively less understood processes such as nanofiltration and forward osmosis are presented, with recent modifications to allow for different solutes and solutions. Mathematical modelling of hybrid systems integrated with RO has also been reviewed. A survey of the literature shows that mathematical and optimization modelling of desalination processes is an exciting area for researchers in which future scholarship includes coupling of renewable energy systems with desalination technologies, as well as more advanced descriptions of fouling evolution other than that of cake filtration in membrane-based processes

Towards a Benign and Viable Rhodium Catalyzed Hydroformylation of Higher Olefins: Economic and Environmental Impact Analyses, Solvent Effects and Membrane-based Catalyst Separation

Researchers at the Center for Environmentally Beneficial Catalysis (CEBC) had previously reported a novel rhodium-based hydroformylation process concept based on the use of CO2-expanded liquids (CXLs) to intensify rates and obtain higher linear/branched aldehydes selectivity at relatively mild temperatures (30-60 °C) and pressures (~4 MPa). This dissertation continues investigations aimed at addressing the fundamental and practical issues associated with this concept. ReactIR studies of Rh/triphenylphosphine-catalyzed 1-octene hydroformylation, complemented by microkinetic and reactor modeling investigations revealed that the intrinsic kinetic rate constants are of similar magnitude with or without CO2 addition to the reaction mixture. This implies that the enhanced reaction rate observed in CXL is due to the increased hydrogen solubility in that medium. Environmental impact analysis revealed that the overall toxicity index for the CEBC process is approximately 40 times less than the Exxon process against which the CEBC process was benchmarked. Economic analysis of the CXL concept revealed that at an aldehyde production rate of 19,900 kg / (kg Rh h), 99.8% rhodium has to be recovered per pass for the CEBC process to be competitive with the Exxon process. Assuming a similar hydroformylation turnover frequency, rhodium recovery levels that exceed this criterion for economic viability were successfully demonstrated in a membrane-based nano/ultra-filtration reactor system using polymer supported phosphorus ligands, synthesized and provided by researchers from the Department of Chemistry. During continuous filtration of a toluene-based solution containing polymer-supported Rh complexes, the Rh and P concentrations in the permeate, quantified using ICP analysis, were on the order of a few tens of ppb. During continuous 1-octene hydroformylation studies in the membrane reactor at a syngas pressure of 0.6 MPa and 60 °C, the 1-octene conversion and product (mostly aldehydes) concentrations reached a steady state with the Rh concentrations in the permeate stream being lower than 120 ppb. However, the conversions and product concentrations during the continuous run are lower than those obtained in a batch ReactIR under identical operating conditions. This is attributed to syngas starvation in the membrane reactor that might be caused by inadequate mixing. In complementary investigations, it was found that the dissolution of CO2 in the organic phase (to create CO2-expanded liquids) decreases the viscosities of the mixtures with increasing CO2 pressure. This offers an opportunity to enhance mixing and also tune the membrane flux so as to increase the throughput of the membrane filter. The demonstrated technology concept, when fully optimized, should find applications in a variety of other applications in homogeneous catalysis, including hydrogenation and carbonylation of conventional and biomass-based substrates