Suchergebnisse

Environmental legislations in the Western world impose stringent effluent quality standards for ultimate protection of the environment. This is also observed in Turkey. The current paper presents efforts made to simulate an existing 0.77 million m(3)/day conventional activated sludge plant located at Ankara, AWTP. The ASM1 model was used for simulation in this study. The model contains numerous stoichiometric and kinetic parameters, some of which need to be determined on case by case bases. The easily degradable COD (SS) was determined by two methods, physical-chemical and respirometric methods, namely. The latter method was deemed unreliable and rejected in the further study. Dynamic simulation with SSSP program predicted effluent COD and MLSS values successfully while overestimating OUR. A complete fit could only be obtained by introducing a dimensionless correction factor (eta(O2)=0.58) to the oxygen term in ASM1.

Environmental legislations in the Western world impose stringent effluent quality standards for ultimate protection of the environment. This is also observed in Turkey. The current paper presents efforts made to simulate an existing 0.77 million m(3)/day conventional activated sludge plant located at Ankara, AWTP. The ASM1 model was used for simulation in this study. The model contains numerous stoichiometric and kinetic parameters, some of which need to be determined on case by case bases. The easily degradable COD (SS) was determined by two methods, physical-chemical and respirometric methods, namely. The latter method was deemed unreliable and rejected in the further study. Dynamic simulation with SSSP program predicted effluent COD and MLSS values successfully while overestimating OUR. A complete fit could only be obtained by introducing a dimensionless correction factor (eta(O2)=0.58) to the oxygen term in ASM1.

A key approach in expediting the transition towards a bio-based economy is the conceptual design and implementation of integrated second-generation biorefineries (iSGB) [1]. Despite tremendous efforts in research as well as past economic and political initiatives, the number of active iSGBs worldwide is dramatically low, mainly due to their deficient economic robustness [2]. A conceptual design approach for these iSGBs is Superstructure Optimization (SSO), which yields an optimal candidate process topology (CPT), but which is inherently limited by the initial search space and the fidelity of the unit operation models [3,4]. This contrasts highly with the complexity of fermentation processes and disregards recent advances in synthetic biology for the optimization of the cell factories employed in these processes [2]. From a biotechnological perspective, this hurdle is surmounted by a design approach, in which the products are specified a priori and subsequently the cell factory and the process are tailored towards the product and finally the feedstock is specified, thus "having the end in mind" [5,6]. Furthermore, by following a simulation-based optimization (SBO) approach, complex models including physiological and operational specifications of cell factories can be employed in the search for an optimal process design. Despite being computationally demanding, the second benefit from it is the possibility to include uncertainties into the process design with models of complex biological systems [7]. In this work, we therefore propose a novel synergistic framework for the synthesis and design of iSGBs: based on a hybrid approach integrating surrogate-based superstructure optimization (SSO) with simulation-based design optimization (SBO), it harnesses both the power of the SSO for process synthesis and the potential of SBO for detailed design optimization. The framework itself capitalizes thorough knowledge regarding biotechnology and synthetic biology in order to guide decisions for both SSO and SBO, which results in a consolidated framework and an expedited evaluation process.

Producción Científica ; Methylocystis hirsuta, a type II methanotroph, has been experimentally demonstrated to be able to efficiently synthesize polyhydroxyalkanoates (PHA) from biogas under nutrient-limited conditions. A mechanistic model capable of describing the relevant processes of M. hirsuta, which is currently not available, would therefore lay a solid foundation for future practical demonstration and optimization of the PHA synthesis technology using biogas. To this end, dedicated batch tests were designed and conducted to obtain experimental data for different mechanistic processes of M. hirsuta. Through utilizing the experimental data of well-designed batch tests and following a step-wise model calibration/validation protocol, the stoichiometrics and kinetics of M. hirsuta are reported for the first time, including the yields of growth and PHA synthesis on CH4 (0.14 ± 0.01 g COD g–1 COD and 0.25 ± 0.02 g COD g–1 COD), the CH4 and O2 affinity constants (5.1 ± 2.1 g COD m–3 and 4.1 ± 1.7 g O2 m–3), the maximum PHA consumption rate (0.019 ± 0.001 g COD g–1 COD d–1), and the maximum PHA synthesis rate on CH4 (0.39 ± 0.05 g COD g–1 COD d–1). Through applying the developed model, an optimal O2:CH4 molar ratio of 1.6 mol O2 mol–1 CH4 was found to maximize the PHA synthesis by M. hirsuta. Practically, the model and parameters obtained would not only benefit the design and operation of bioreactors performing PHA synthesis from biogas, but also enable specific research on selection for type II methanotrophs in diverse environments. ; Australian Research Council (ARC) through Future Fellowship (FT160100195) ; Junta de Castilla y León y EU-FEDER (CLU 2017-09) y (UIC 71) ; European Union's Horizon 2020 research and innovation program. grant agreement no. 790231.