| 1421. |
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| 1422. |
- De Windt, Laurent, et al.
(författare)
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MSWI bottom ash used as basement at two pilot-scale roads : comparison of leachate chemistry and reactive transport modeling
- 2011
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 31:2, s. 267-280
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Tidskriftsartikel (refereegranskat)abstract
- The recycling of municipal solid waste incineration bottom ash as aggregates for road basement requires assessing the long-term evolution of leachate chemistry. The Dåva (Sweden) and Hérouville (France) pilot-scale roads were monitored during 6 and 10 years, respectively. Calculated saturation indices were combined to batch test modeling to set a simplified geochemical model of the bottom ash materials. A common reactive transport model was then applied to both sites. At Hérouville, pH and the concentration of most elements quickly drop during the first two years to reach a set of minimum values over 10 years. The decrease is less pronounced at Dåva. The evolutions of pH and major element concentrations are fairly well related to the following pH-buffering sequence: portlandite, C-S-H phases or pseudo-wollastonite and, finally, calcite in equilibrium with atmospheric CO2. Al(OH)3, barite, ettringite and monohydrocalcite may also control leachate chemistry. Cu release is correctly modeled by DOM complexation and tenorite equilibrium. Temperature has no significant effect on the modeling of leachate chemistry in the range 5-30 °C, except at high pH. Effects at road edges and roadside slopes are important for the release of the less reactive elements and, possibly, for carbonation processes.
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| 1423. |
- De Windt, L., et al.
(författare)
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Reactive transport modeling of leachate evolution of MSWI bottom ash used as road basement : Hérouville (France) and Dåva (Sweden) sites
- 2009
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The recycling of municipal solid waste of incineration (MSWI) bottom ash as aggregates for road basement requires a better characterization of the evolution of leachate chemistry over a timescale of many decades. In this paper, a common reactive transport model is applied to the Hérouville (France) and Dåva (Sweden) pilot roads whose leachate emissions have been sampled during 10 and 6 years, respectively. The model considers simultaneously the hydrodynamic processes (rain water infiltration, advective and diffusive transport), pH-buffering and solubility-controlled processes by secondary minerals, ageing by atmospheric carbonation, and the leachate chemistry (major elements and trace metals such as Al, Cu, Pb). The evolution of pH is fairly well simulated with the following pH-buffering sequence: portlandite, calcium silicate hydrate (CSH), ettringite and, finally, calcite. The quantity of CO2 dissolved in the percolating rain water is generally not sufficient to explain the pH evolution and carbonation processes, requiring atmospheric gaseous inputs. The relation between pH evolution and element release is discussed for both sites. Calculated Pb release is overestimated when based on solubility-controlled mechanisms only. Edge effects are shown to be important at both sites with an emphasis of carbonation and release of non reactive elements. Temperature has no significant effect on the calculated leachate chemistry in the range of 5 - 30° C, except at high pH.
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| 1424. |
- Delin, Staffan, et al.
(författare)
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Utveckling av riktningsanalys exergiberäkningar i Luleå och Strängnäs kommuner eller Hur kan man veta om man hushållar med resurserna på ett hållbart sätt?
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bakgrunden till projektet är den riktningsanalys som utvecklades av Eva Grundelius år 1991. Riktningsanalysen som är uppbyggd kring sex frågor fungerar som en checklista för hållbar utveckling. Den kan användas i många slag av beslutssituationer. För att göra riktningsanalysen mer operativ och kvantifierbar har den i detta projekt kopplats samman med en exergianalys. Exergi är ett fysiskt mått på resursers värde. Denna analys görs med utgångspunkt från det livsuppehållande systemet, ekosystemet. För att mänskligheten ska överleva på sikt får inte exergikostnaderna överstiga intäkterna i exergiformer. Detta gäller också för ett hållbart projekt och ett hållbart samhälle. I rapporten behandlas olika alternativ för att behandla avlopp från en by i Luleå kommun. I Strängnäs är det olika alternativ för behandling av hushållsavfall som analyseras.
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| 1425. |
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| 1426. |
- Deng, Zhiqiang, et al.
(författare)
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Variable residence time-based model for BOD removal in free-water surface wetlands
- 2016
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Ingår i: Ecological Engineering. - : Elsevier BV. - 0925-8574. ; 97, s. 334-343
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Tidskriftsartikel (refereegranskat)abstract
- Constructed wetlands have been increasingly used for treatment of secondary wastewater containing various contaminants. This paper presents a Variable Residence Time (VART)-based model, called VART-BOD model, for simulation of BOD removal processes in constructed wetlands with free water surface (FWS). Mathematically, the VART-BOD model describes a free water surface wetland with three vertical layers, including vegetated water column layer, advection-dominated upper root layer, and diffusion-dominated lower root layer. Biogeochemically, the VART-BOD model simulates various BOD removal processses and mechanisms, including monod kinetics of bacterial growth, mass exchange between water column and root layers, advection, dispersion, and diffusion. A unique feature of the VART-BOD model is the incorporation of a dynamic diffusion-dominated root-zone. The VART-BOD model was tested with data collected from two distinct FWS wetlands: Gustine Wetland, USA and Manzala Wetland, Egypt. Testing results showed that the coefficient of determination (r2) and root mean square error (RMSE) values vary in the ranges of 0.73–0.99 and 0.41–8.70 mg/L, respectively, for Gustine Wetland cells while r2 = 0.98 and RMSE = 0.72 mg/L for Manzala Wetland. The VART-BOD model is a reliable and efficient tool for designing constructed wetlands and for understanding effects of various processes and mechanisms on the treatment efficiency of wastewater in constructed wetlands.
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| 1427. |
- Derda, Patrycja, et al.
(författare)
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Fate of Alkali Metals during Co-Combustion of Biodiesel Residues with Coal in a Semi-Industrial CFB Boiler
- 2008
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Ingår i: 9th International Conference on Circulating Fluidized Beds, CFB 2008, in Conjunction with the 4th International VGB Workshop on Operating Experience with Fluidized Bed Firing Systems; Hamburg; Germany; 13 May 2008 through 16 May 2008. - 9783930400577
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Konferensbidrag (refereegranskat)abstract
- The use of biodiesel, especially of Rapeseed Methyl Ester (RME), has recently increased inthe European countries. This gives rise to an increasing amount of after production residues. Rapeseedcake is the main residue of the RME production process, and may become available in large amounts forenergy recovery. Since rapeseed cake contains high levels of alkali metals, it may cause bedagglomeration, deposit formation and corrosion upon combustion in fluidized beds.This paper presents the fate of alkali metals formed during co-combustion of coal and up to 25% ofrapeseed cake pellets in a 12 MW Circulating Fluidized Bed Boiler at Chalmers University ofTechnology (Sweden). Standard fuel analyses combined with sequential leaching and SEM/EDX, showedthe alkali entering the boiler. Gaseous emissions, bed samples, fly ash and deposits were analyzed inorder to monitor the alkali metals distribution. Gaseous alkali chlorides were measured upstream from theconvective pass at a flue gas temperature of 800 oC using an In-situ Alkali Chloride Monitor (IACM). Inthe same location, deposits were collected on a deposit probe fitted with rings for SEM/EDX analysis.Re-circulated bed material was analyzed as well.Two-day tests showed successful co-firing of up to 25% rapeseed cake on energy basis in the semiindustrialfluidized-bed boiler. Alkali metals were enriched in fly ash. No significant difference could benoticed in the distribution of alkali metals when increasing the share of rapeseed cake from 15% to 25%on energy basis. In the near future, further studies will be carried out to determine the influence oflimestone on the performed tests.
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| 1428. |
- Diener, Derek, 1977, et al.
(författare)
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Material Flow Analysis as a Tool for Product End-of-use Management
- 2013
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Ingår i: PERSPECTIVES ON MANAGING LIFE CYCLES – PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON LIFE CYCLE MANAGEMENT.
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Konferensbidrag (refereegranskat)abstract
- Material flow analysis (MFA) has been widely used as a tool to assess national and regional material flows. Using a case study, this paper demonstrates one other way to use MFA: as a tool for a company’s product end-of-use (EoU) management. Three main activities emerged during the study with valuable results: (1) the traditional MFA provided flow diagrams, (2) inflow analysis allowed basic feasibility analysis of EoU product capture, and (3) product chain description provided a rough sketch of key actors and their decisions. Together, results can be used as the foundation for understanding product fate and reveal potential avenues and barriers to improving a company’s EoU management.
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| 1429. |
- Diener, Derek, 1977, et al.
(författare)
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Silver i produktkedjan: Från konsumentvaror till avloppsslam
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Under senare år har ett antal nya produkter innehållande silver lanserats, till exempel sårvårdsprodukter, tvättmaskiner och textilier. Inte minst har mängden nanosilverpartiklar ökat kraftigt. När detta silver når avloppsreningsverken kan det dels påverka processerna i verken, men framför allt påverkas kvalitén på det slam som produceras. Syftet med detta projekt var, i korthet, att undersöka de viktiga produktkedjor som avslutas med att silver hamnar i svenska avloppsreningsverk och att därmed bidra till en bättre förståelse för problemet.Arbetet utfördes som ett examensarbete under 2011 av Derek Diener under handledning av Ulrika Palme på avdelningen för miljösystemanalys på Chalmers tekniska högskola i Göteborg. Studien stöttades med finansiering av Svenskt Vatten Utveckling, och med rådgivning från en referensgrupp bestående av representanter för Borås VA, Gryaab och Hammargårds ARV, vilka vi härmed vill tacka för det ekonomiska såväl som det kunskapsmässiga stöd vi fått. Vi vill även tacka alla de personer som bidragit med sin tid och sina kunskaper, tankar och åsikter i intervjuer, möten och enkäter.Denna rapport är en översatt och för Svenskt Vatten Utveckling anpassad version av Derek Dieners rapport ”Silver in the product stream: From consumer goods to sludge and water ecosystems with a focus on stakeholder positions”.
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| 1430. |
- Diener, Silvia, et al.
(författare)
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Accelerated carbonation of ashes and steel slags in a landfill cover construction
- 2008
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Ingår i: Proceedings of Second International Conference on Accelerated Carbonation for Environmental and Materials Engineering. - : University of Rome "La Sapienza". ; , s. 389-400
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Konferensbidrag (refereegranskat)abstract
- Fly ash from biofuel incineration and slags from steel production were used in two full scale applications of cover constructions on municipal solid waste (MSW) landfills. The long-term stability of the cover materials is studied in a designed laboratory experiment. The impact of six environmental factors on accelerated carbonation is investigated over a period of three years. Leaching behaviour, acid neutralization capacity, mineral composition (XRD) and thermo gravimetrical behaviour (TG) are tested after different periods of ageing under different conditions. By now samples were taken after three and ten months of ageing. Multivariate data analysis was used for data evaluation. The results indicate the factors material, ageing time and carbon dioxide content of the atmosphere to be most relevant.
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