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A model to predict the behavior of UASB reactors
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.ORCID iD: 0000-0001-8241-2225
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
2013 (English)In: International Journal of Environmental Research, ISSN 1735-6865, E-ISSN 2008-2304, Vol. 7, no 3, 705-714 p.Article in journal (Refereed) Published
Abstract [en]

A model describing the main processes occurring in the UASB reactor was developed; in order to maintain simplicity and applicability of the model, only the fundamental aspects were considered. In the model, the reactor is divided in several well-stirred reactors coupled in series and it comprises substrate degradation, biomass growth and the reactions that take place within the granules. The important contribution of the paper is the development of a model taking into account the mass transfer through the film around the granules, the intra-particle diffusion, and the degradation reaction. The model enables the determination of the removal efficiency of the substrate and the increase of both the height of the sludge bed and the granule size with time. The simulated results of an experimental UASB reactor treating sugar-cane mill wastewater were found to be in good agreement with the performance of the reactor. The sensitivity analysis shows that the performance of the reactor is determined by several parameters. The most important parameters are: the bioconversion rate, the mass transfer coefficient in the film, the intra-particle diffusivity, the volumetric fraction of biomass in the reactor, and the number of CSTR considered. These parameters should therefore be carefully determined. The model could be a useful tool in the optimization and development of UASB reactors.

Place, publisher, year, edition, pages
2013. Vol. 7, no 3, 705-714 p.
Keyword [en]
CSTR, Kinetic, Simulation, UASB, Wastewater
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-133846ISI: 000319952600009ScopusID: 2-s2.0-84882252637OAI: diva2:663520

QC 20131112

Available from: 2013-11-12 Created: 2013-11-11 Last updated: 2016-02-26Bibliographically approved
In thesis
1. Closing the Loop by Combining UASB Reactor and Reactive Bed Filetr Technology for wastewater Treatment: Modelling and Practical Approaches
Open this publication in new window or tab >>Closing the Loop by Combining UASB Reactor and Reactive Bed Filetr Technology for wastewater Treatment: Modelling and Practical Approaches
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A laboratory-scale upflow anaerobic sludge blanket (UASB) reactor followed by a packed bed reactor (PBR) filled with Sorbulite® in the lower part and Polonite® in the upper part was used to treat household wastewater in a 50-week experiment. A model was developed to describe the performance of the UASB reactor, including mass transfer through the film around anaerobic granules, intra-particle diffusion and bioconversion of the substrate. In a second model, a numerical expression describing the kinetics occurring in the granules was developed. It includes the resistances through which the substrate passes before biotransformation. These expressions were then linked to governing equations for the UASB reactor in order to describe degradation of the substrate, biomass growth (active and inactive), and variation in granule size over time. A third model was developed to describe the profile of the phosphorus (P) concentration throughout the PBR. In a first attempt, the analytical and numerical model was applied to data taken from previous studies in which UASB reactors were used to treat sugarcane mill wastewater and slaughterhouse wastewater. The results showed good agreement between observed and simulated results. Sensitivity analysis showed that diffusion coefficient and yield were important parameters in the UASB reactor model.The laboratory bench-scale experiment revealed that the combined UASB-PBR system efficiently treated the residential wastewater. Phosphorus, BOD7 and pathogenic bacteria all showed average removal of 99%, while total nitrogen showed a moderate reduction in the system (40%). Application of the numerical solution model to the experimental UASB reactor used resulted in good agreement between simulated and experimental values. Regarding the PBR, the model developed successfully predicted P removal. For both models, the capability and sensitivity analyses identified important parameters. A treatment system aiming to close the loop is suggested based on sequential UASB and PBR with biogas collection, nutrient recycling via sludge and filter media and elimination of pathogenic organisms.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. xvi, 50 p.
TRITA-LWR. PHD, ISSN 1650-8602 ; 2016:02
Bench-scale experiment, Modelling, Polonite, Sorbulite, UASB, Wastewater
National Category
Environmental Engineering
Research subject
Land and Water Resources Engineering
urn:nbn:se:kth:diva-182990 (URN)978-91-7595-878-1 (ISBN)
Public defence
2016-03-18, Sal V1, Teknikringen 76, KTH, Stockholm, 10:00 (English)

QC 20160226

Available from: 2016-02-26 Created: 2016-02-24 Last updated: 2016-02-26Bibliographically approved

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