| 1. |
- Carlsson, Bengt, et al.
(författare)
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Fault detection and isolation of sensors in aeration control systems
- 2016
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 73:3, s. 648-653
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we consider the problem of fault detection (FD) and isolation in the aeration system of an activated sludge process. For this study, the dissolved oxygen in each aerated zone is assumed to be controlled automatically. As the basis for an FD method we use the ratio of air flow rates into different zones. The method is evaluated in two scenarios: using the Benchmark Simulation Model no. 1 (BSM1) by Monte Carlo simulations and using data from a wastewater treatment plant. The FD method shows good results for a correct and early FD and isolation.
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| 2. |
- Chernomoretz, Ariel, et al.
(författare)
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The Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) International Consortium inaugural meeting report
- 2016
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Ingår i: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) International Consortium is a novel, interdisciplinary initiative comprised of experts across many fields, including genomics, data analysis, engineering, public health, and architecture. The ultimate goal of the MetaSUB Consortium is to improve city utilization and planning through the detection, measurement, and design of metagenomics within urban environments. Although continual measures occur for temperature, air pressure, weather, and human activity, including longitudinal, cross-kingdom ecosystem dynamics can alter and improve the design of cities. The MetaSUB Consortium is aiding these efforts by developing and testing metagenomic methods and standards, including optimized methods for sample collection, DNA/RNA isolation, taxa characterization, and data visualization. The data produced by the consortium can aid city planners, public health officials, and architectural designers. In addition, the study will continue to lead to the discovery of new species, global maps of antimicrobial resistance (AMR) markers, and novel biosynthetic gene clusters (BGCs). Finally, we note that engineered metagenomic ecosystems can help enable more responsive, safer, and quantified cities.
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| 3. |
- Diehl, Stefan, et al.
(författare)
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Steady-state analysis of activated sludge processes with a settler model including sludge compression
- 2016
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Ingår i: Water Research. - : Elsevier BV. - 1879-2448 .- 0043-1354. ; 88:1, s. 104-116
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Tidskriftsartikel (refereegranskat)abstract
- A reduced model of a completely stirred-tank bioreactor coupled to a settling tank with recycle is analyzed in its steady states. In the reactor, the concentrations of one dominant particulate biomass and one soluble substrate component are modelled. While the biomass decay rate is assumed to be constant, growth kinetics can depend on both substrate and biomass concentrations, and optionally model substrate inhibition. Compressive and hindered settling phenomena are included using the Bürger-Diehl settler model, which consists of a partial differential equation. Steady-state solutions of this partial differential equation are obtained from an ordinary differential equation, making steady-state analysis of the entire plant difficult. A key result showing that the ordinary differential equation can be replaced with an approximate algebraic equation simplifies model analysis. This algebraic equation takes the location of the sludge-blanket during normal operation into account, allowing for the limiting flux capacity caused by compressive settling to easily be included in the steady-state mass balance equations for the entire plant system. This novel approach grants the possibility of more realistic solutions than other previously published reduced models, comprised of yet simpler settler assumptions. The steady-state concentrations, solids residence time, and the wastage flow ratio are functions of the recycle ratio. Solutions are shown for various growth kinetics; with different values of biomass decay rate, influent volumetric flow, and substrate concentration.
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| 4. |
- Nookuea, Worrada
(författare)
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Impacts of Thermo-Physical Properties on Chemical Absorption for CO2 Capture
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Following the climate change mitigation target in Paris agreement, the global warming has to be limited to 2.0°C above the preindustrial levels. One of the potential methods is carbon capture and storage (CCS), which can significantly reduce the CO2 emissions from the vast point sources such as power plants, industries, and natural gas processes. The CCS covers four steps which are capture, conditioning, transport, and storage. For the capture part, post-combustion capture is easier to implement based on today’s technologies and infrastructure compared with pre-combustion and oxy-fuel combustion captures, since the radical changes in the structure of the existing plant are not required.To design and operate different CCS processes, the knowledge of thermo-physical properties of the CO2 mixtures is of importance. In this thesis, the status and progress of the studies related to the impacts of the uncertainty in thermo-physical properties on the design and operation of the CCS processes were reviewed. The knowledge gaps and the priority of property model development were identified.According to the identified knowledge gaps in the review, the impacts of thermo-physical properties which are the density, viscosity, and diffusivity of the gas and liquid phases, and the surface tension and heat capacity of the liquid phase on the design of the absorber column for the chemical absorption using aqueous monoethanolamine were quantitatively analyzed. An in-house rate-based absorption model was developed in MATLAB to simulate the absorption process, and the sensitivity study was done for each property. An economic evaluation was also performed to further estimate the impacts of the properties on the capital cost of the absorption unit. For column diameter of the absorber, the gas phase density shows the most significant impacts; while, the liquid phase density and viscosity show the most significant impacts on the design of the packing height and also the capital cost of the absorption unit. Therefore, developing the flue gas density model and liquid phase density and viscosity models of the aqueous solvents with CO2 loading should be prioritized.
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| 5. |
- Pierong, Rasmus, et al.
(författare)
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Algae Based Wastewater Treatment Model Using The RWQM1
- 2016
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Ingår i: Proc. IWA World Water Congress & Exhibition. - Brisbane, Australia.
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a model describing the dynamics of an algae based wastewater treatment process in an activated sludge environment. As the basis for the process modelling, the River Water Quality Model no. 1 (RWQM1) is chosen. In order to evaluate the applicability of the model to an activated sludge process, the proposed model is compared to the Activated Sludge Model no. 1 (ASM1).
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| 6. |
- Zambrano, Jesús, et al.
(författare)
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A simple model for algae-bacteria interaction in photo-bioreactors
- 2016
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Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 19:nov, s. 155-161
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a simple model to describe the consortia of algae-bacteria in a photo-bioreactor. The model is inspired by the Activated Sludge Model (ASM) structure, which includes different process rates and stoichiometric parameters. The model comprises two main biomass populations (algae and bacteria), two dissolved substrates (ammonium and nitrate) and two dissolved gases (oxygen and carbon dioxide) in the reactor. The model was calibrated with data from batch experiments performed in two lab-scale photo-bioreactors. A sensitivity analysis was done to identify the parameters to be considered for the model calibration. Results indicate that the maximum algae and bacteria growth rate, bacteria growth yield and half-saturation constant for carbon were the most sensitive parameters. Moreover, the comparison between the experiments and the model shows good agreement in terms of predicting the ammonium, nitrate and oxygen concentrations in the photo-bioreactor.
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| 7. |
- Zambrano, Jesús, et al.
(författare)
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A Simplified Model of an Activated Sludge Process with a Plug-Flow Reactor
- 2016
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Konferensbidrag (refereegranskat)abstract
- The analysis of a simplified activated sludge process (ASP) with one main dissolved substrate and one main particulate biomass component has been conducted with respect to its steady-state. The ASP is formed by a plug flow reactor (PFR) and a settler with the recycling going to the reactor. The biomass growth rate is described by a Monod function. For this process, it is not possible to get an explicit expression for the effluent substrate concentration when the process is subject to a fixed sludge age. However,in the normal case when the influent substrate concentration is much greater than the effluent substrate concentration, then an explicit approximation for the effluent as a function of the influent and the process parameters is obtained. This work includes numerical examples considering two models for the settler. One model is the ideal settler, which assumes a complete thickening of the activated sludge through the underflow of the settler. The other model takes into account hindered settling and sludge compression. Numerical results show the effectiveness and the limitations of the proposed solution under these scenarios.
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| 8. |
- Zambrano, Jesús, et al.
(författare)
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A simplified model of an activated sludge process with a plug-flow reactor
- 2016
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Ingår i: Proceedings of The 9th Eurosim Congress on Modelling and Simulation EUROSIM 2016, The 57th SIMS Conference on Simulation and Modelling SIMS 2016. - : Linköping University Electronic Press. - 1650-3740 .- 1650-3686. - 9789176853993 ; 142, s. 824-830
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Konferensbidrag (refereegranskat)abstract
- The analysis of a simplified activated sludge process (ASP) with one main dissolved substrate and one main particulate biomass has been conducted in steady-state conditions. The ASP is formed by a plug-flow reactor anda settler tank. The biomass growth rate is described by a Monod function. For this process, it is not possible to get an explicit expression for the effluent substrate concentration when the process is subject to a fixed sludge age.However, when the substrate concentration of the influent is much greater than that of the effluent, an approximate and explicit relation between them is obtained. Numerical examples with two models for the settler are presented. One model is the ideal settler, which assumes a completethickening of the sludge. The other model includes hindered settling and sludge compression. Numerical results show the effectiveness and the limitations of the proposed solution under these scenarios.
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| 9. |
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| 10. |
- Zambrano, Jesús, et al.
(författare)
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Monitoring a Secondary Settler Using Gaussian Mixture Models
- 2016
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Konferensbidrag (refereegranskat)abstract
- This paper presents a method for monitoring the sludge profiles of a secondary settler using a Gaussian Mixture Model (GMM). A GMM is a parametric probability density function represented as a weighted sum of Gaussian components densities. To illustrate this method, the current approach is applied using real data from a sensor measuring the sludge concentration as a function of the settler level at a wastewater treatment plant (WWTP) in Bromma, Sweden. Results suggest that the GMM approach is a feasible methodfor monitoring and detecting possible disturbances of the process and fault situations such as sensor clogging. This approach can be a valuable tool for monitoring processes with a repetitive profile.
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