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  • 1.
    Vidal, Brenda
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Barraud, Sylvie
    Department of Civil Engineering and Urban Planning, National Institute of Applied Sciences of Lyon.
    Kärrman, Erik
    Division of the Built Environment, Research Institutes of Sweden.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Assessing the sustainability of on-site sanitation systems using multi-criteria analysis2019In: Environmental Science: Water Research & Technology, ISSN 2053-1400, Vol. 5, p. 1599-1615Article in journal (Refereed)
    Abstract [en]

    Small on-site sanitation systems are widely present in suburban and rural areas in many countries. As these systems often underperform and have an impact on receiving waters, understanding their overall sustainability is of interest for policy and decision-makers. However, the definition and estimation of indicators defining sustainability are challenging, as it is finding the methodological approach to combine qualitative and quantitative indicators into one comprehensive assessment. In this study, twelve indicators defined by environmental, economic, social, technical and health-related criteria were used to compare nine alternatives of on-site sanitation for single households. A non-compensatory method for multi-criteria decision analysis, ELECTRE III, was used for the assessment together with weights assigned to each indicator by a reference group. Several scenarios were developed to reflect different goals and a sensitivity analysis was conducted. Overall, the graywater–blackwater separation system resulted as the most sustainable option and, in terms of polishing steps for phosphorus removal, chemical treatment was preferred over the phosphorus filter, both options being implemented together with sand filters. Assessing the robustness of the systems was a crucial step in the analysis given the high importance assigned to the aforementioned indicator by the stakeholders, thus the assessment method must be justified. The proposed multi-criteria approach contributes to aid the assessment of complex information needed in the selection of sustainable sanitation systems and in the provision of informed preferences.

  • 2.
    Nyström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordqvist, Kerstin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Treatment of road runoff by coagulation/flocculation and sedimentation2019In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 79, no 3, p. 518-525Article in journal (Refereed)
    Abstract [en]

    A laboratory investigation of the treatment potential of a coagulation process in the context of stormwater treatment was undertaken. The initial 25 L road runoff generated from four rain events was collected and subjected to a jar-testing regime with two commercial coagulants. The treatment effect was assessed by analysing the runoff before and after treatment for turbidity, suspended solids and metal content. The coagulation process resulted in particle and total metal reduction of more than 90% compared to 40% for only sedimentation. Up to 40% reduction of dissolved Cr, Cu and Pb was also observed compared to 0% for sedimentation. This study shows that coagulation may be a useful process for stormwater treatment systems when the treatment requirements are high.

  • 3.
    Vidal, Brenda
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Phosphorus reduction in filters for on-site wastewater treatment2018In: Journal of Water Process Engineering, ISSN 2214-7144, Vol. 22, p. 210-217Article in journal (Refereed)
    Abstract [en]

    Discharges of phosphorus (P) from on-site wastewater treatment systems generally contribute to eutrophication problems in Swedish freshwaters and, ultimately, in the Baltic Sea. Such concerns have led to a growing interest in improving P removal in treatment facilities. This study investigated the reduction of P in 12 full-scale on-site treatment systems featuring sand filters and alkaline P-filters by sampling and analysing filter influents and effluents. The flow-proportional samples collected were analysed for total and dissolved P, BOD7, total and dissolved organic carbon (TOC and DOC), and pH. Seven of the eight investigated sand filters did not provide satisfactory total P reduction; the likely explanations are filter clogging and wastewater dilution by extraneous water. In addition, effluents from four of the eight sand filters had total P concentrations higher than 3 mg L−1, which is the Swedish effluent limit recommended for common receiving waters, indicating that a subsequent polishing step would be needed. Six of the nine investigated P-filters reduced P adequately, with total P concentrations in the effluent ranging between 0.1 and 1.9 mg L−1. The three underperforming P-filters had effluent pH values below 9; filter age, clogging, and hydraulic overload were identified as probable reasons for their poor performance. A statistically significant correlation was found between total-P reduction and filtrate pH, but no significant correlation was detected between organic load in the influent and P reduction by the P-filters. The P-filter media replacement frequency could not be established, but filtrate pH appeared to be a good estimator.

  • 4.
    Vidal, Brenda
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Sharp, Liz
    Department of Civil and Structural Engineering University of Sheffield.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    What are the drivers to decentralize wastewater treatment systems?: A Swedish perspective2018Conference paper (Refereed)
  • 5.
    Vidal, Brenda
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kärrman, E.
    RISE Research Institute of Sweden, Urban Water management.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    An environmental approach to compare on-site sanitation systems2017Conference paper (Refereed)
  • 6.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Vidal, Brenda
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Discharge of indicator bacteria from on-site wastewater treatment systems2017In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 91, p. 365-373Article in journal (Refereed)
    Abstract [en]

    Small-scale on-site wastewater treatment facilities present the risk of microbial pollution of groundwaterused for drinking water and surface water used for recreational purposes. This study assessedthe discharge of indicator bacteria, total coliform, Escherichia coli, intestinal enterococci and Clostridiumperfringens, by flow-proportional sampling from 12 full-scale on-site treatment systems featuringbiological treatment units (mainly sand filters) and alkaline filter beds for phosphorus treatment(P-filters). Correlations of effluent bacterial concentrations with pH, total and dissolved organic carbon,filter age and hydraulic load were evaluated. The bacterial concentrations in the effluents ofthe sand filters were considerable. The concentrations for excellent bathing water quality set in theEU bathing water directive, 200 and 500 colony forming units (cfu)/100 mL for intestinal enterococciand E. coli, respectively, were exceeded in three (intestinal enterococci) and one (E. coli) of the eightinvestigated sand filters. In one of the sand filters, effluent E. coli concentrations were high althoughno obvious malfunction of the filter was observed. In the effluent from the other investigated biologicaltreatment units (a trickling fibre filter, two units with attached growth treatment and one aeratedactivated sludge technique), bacterial concentrations were very high (75,000 cfu/100 mL of Clostridiumperfringens and 85,000 cfu per 100 mL of total coliform), possibly because of a shorter retention time ofthe wastewater in these facilities, missing aeration and little time between start-up and measurements.Three and four of the nine investigated P-filters exceeded excellent bathing water quality in coastalwaters as stipulated by the EU bathing water directive in respect of E. coli and intestinal enterococci,respectively.

  • 7.
    Nyström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordqvist, Kerstin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Removal of small particles from urban snow melt mixture by coagulation/flocculation and sedimentation2017In: 14th IWA/IAHR International Conference on Urban Drainage: Conference Proceedings, 2017, 2017Conference paper (Other academic)
    Abstract [en]

    This abstract presents a laboratory study of a coagulation/flocculation process on an urban snow melt mixture. Coagulation/flocculation is ubiquitous in water treatment, but has seen little use in the stormwater context. Using a jar-test procedure five different chemicals are evaluated as primary coagulants and their treatment performance on urban snow melt with respect to solids removal and metal content. Particle-size distribution measurements will indicate the process effect on different size fractions in the urban snow melt. Analysis for metal content will show the extent of metal reduction that occurs, either by separating out the particulate fraction or due to precipitation reactions.

  • 8.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Vidal, Brenda
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Slutrapport av projekten "Fosforfällor för små avlopp - hur länge fungerar de?" och "Bakterieutsläpp från små avlopp"2017Report (Other academic)
    Abstract [sv]

    Små enskilda avloppsanläggningar i Sverige består ofta av en slamavskiljare med markbädd eller infiltration. I områden med hög skyddsnivå har på senare år ett stort antal fosforfilter installerats. Syftet med denna studie var att undersöka markbäddars och fosforfilters förmåga att reducera halten bakterier och fosfor i avloppsvattnet. Avloppsanläggningar i Västerbotten, Norrbotten och Norrtälje kommun identifierades och inspekterades. Prover togs mellan september 2015 och september 2016 från tolv avloppsanläggningar, åtta markbäddar och nio fosforfilter. Provtagning skedde minst tre gånger vid varje anläggning, och varje provtagningstillfälle varade cirka 3–4 timmar då det togs två stickprover från slamavskiljarens tredje kammare alternativt från fördelningsbrunnen, samt två flödesproportionella samlingsprover efter den biologiska reningen (det vill säga efter markbädden eller biosteget i minireningsverket) och efter fosforfiltret. I proverna mättes pH, mängden suspenderat material, temperatur, indikatorbakterier (E. coli, totala koliforma, intestinala enterokocker och Clostridium perfringens/C. perfringens), halten löst och total fosfor, halten löst och totalt organiskt kol (DOC, TOC) samt BOD. Spårämnesförsök genomfördes i tre fosforfilter med färgen rhodamin.

     

    22 av de 34 inspekterade avloppsanläggningarna (65 procent) lämpade sig inte för flödesproportionell provtagning, vilket visar på svårigheten med att kontrollera funktionen av små avloppsanläggningar med hjälp av provtagning. Nio av 21 inspekterade fosforfilter lämpade sig inte för provtagning på grund av att det inte fanns något vattenflöde genom filtret, vilket indikerar att filtren inte fungerade som avsett.

     

    I utloppen från tre av de åtta undersökta markbäddarna var medelkoncentrationen intestinala enterokocker högre än badvattendirektivets gränsvärde för inlandsvatten med utmärkt vattenkvalitet. För E. coli-koncentrationer var detta fallet bara i en enda markbädd, men detta trots att det utgående vattnet var klart och hade TOC koncentrationer på en acceptabel nivå. Det här visar att bakteriekoncentrationer kan vara höga även om markbädden ser ut att fungera.

     

    Efter de nio undersökta fosforfiltren var bakteriekoncentrationen särskilt hög efter fosforfilter utan markbädd som förbehandlingssteg. I flera fall översteg koncentrationerna gränsvärdet för utmärkt badvattenkvalitet enligt badvattendirektivet; i tre fosforfilter med avseende på E. coli och i fyra fosforfilter med avseende på intestinala enterokocker. Medelkoncentrationen av E. coli-bakterier reducerades signifikant (p = 0,044) i fosforfiltren, vilket tyder på att fosforfilter kan tjäna som ett reningssteg som ytterligare reducerar bakterier. Detta kunde dock inte påvisas för intestinala enterokocker, totala koliforma eller C. perfringens. Koncentrationen av koliforma bakterier var beroende av fosforfiltrets hydrauliska belastning, vilket tyder på att flödesregimen och vattnets uppehållstid i filtret är viktiga parametrar som påverkar bakteriereduktionen. Både för markbäddarna och för fosforfiltren fanns ett samband mellan koncentrationen av indikatorbakterierer och utloppskoncentrationen av TOC och DOC, vilket tyder på att en högre halt av organiskt kol i utgående vatten visar på en sämre bakteriereduktion.

     

    Två av de åtta undersökta markbäddarna visade på god fosforreduktion som uppgick till 70 procent (slamavskiljare exkluderad) vilket krävs vid normal skyddsnivå enligt nuvarande regelverk. Fosforreduktionen i tre andra markbäddar var lägre (21–29 procent). Övriga tre markbäddar kunde inte betraktas vara godtagbara reningsanläggningar eftersom det troligtvis skedde en betydande inströmning av vatten in i dessa markbäddar med utspädning som följd.

     

    Den högsta koncentrationen av fosfor i utgående vatten från en markbädd var omkring 15 mg/l. Dock var utgående fosforkoncentrationer från de undersökta markbäddarna endast i fyra av åtta fall så höga (>2mg/l) att ett efterföljande fosforfilter skulle vara meningsfullt. Därför är det viktigt att markbäddar med efterföljande rening i fosforfilter byggs med tätskikt för att undvika in- och exfiltration.

     

    Fem av de nio utvärderade fosforfiltren reducerade (tillsammans med den biologiska förbehandlingen) mer än 90 procent av den inkommande fosforn från slamavskiljaren. Det betyder att de klarade reningskravet för fosfor i områden med hög skyddsnivå. Två av filtren uppvisade utgående koncentrationer av totalfosfor på 1–3 mg/l och den högsta utgående medelkoncentrationen var 4,4 mg/l. I anläggningar med biologiska behandlingsenheter som inte var markbäddar stod fosforfiltren för merparten av fosforavskiljningen.

     

    Fosforreduktionen i fosforfiltren korrelerade med pH i utgående vatten från filtren, med en beräknad korrelationskoefficient på 74 procent, vilket indikerar att pH kan användas som indikator på filtrets funktion. Dock visade resultaten också att fosforfilter med liknande pH-värde (nära 9) kan skilja sig mycket med avseende på fosforreduktion.

     

    Koncentration av organiskt kol eller fosfor i inkommande vatten till fosforfiltren kunde inte korreleras till filtrens fosforreducerade förmåga. En hög hydraulisk belastning påverkade dock fosforfiltrens funktion negativt. Liknande effekt hade filtrets ålder, om än inte lika tydligt. De preliminära resultaten från spårämnesförsöken indikerar att de fosforfilter som hade längre uppehållstid också hade högre fosforavskiljning än filter med kortare uppehållstid.

  • 9.
    Nyström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordqvist, Kerstin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Flocculation and membrane filtration of stormwater: laboratory experiments2016Conference paper (Other academic)
  • 10.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Vidal, Brenda
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Treatment of Phosphorus and Bacteria in Filters used for On-Site Sanitation in Cold Climate2016Conference paper (Refereed)
    Abstract [en]

    Swedish rural on-site wastewater facilities need to reduce the phosphorus (P) concentrations in the wastewater to prevent eutrophication of the Baltic Sea, as well as the bacteria concentrations to comply with EU standards for bathing water quality. The aim of this study was to investigate two different on-site filter systems at full-scale, sand filters and (often subsequently used) alkaline P filters towards their performance to treat P and bacteria from domestic wastewater. Flow-proportional composite samples were taken from five sand filter beds and two P filters. Four of the five investigated sand filters considerably reduced the concentration of total P in the wastewater. However, infiltrating soil / ground water may have diluted the effluents. The investigated P filters varied in performance. While one of them treated P effectively, the other one performed poorly, probably due to old age and clogging. Low inlet P concentrations impeded the general assessment of the P filters’ efficiency. Concentrations of four indicator bacteria, intestinal enterococci, E. coli, total coliforms and C. perfringens, were considerably reduced in four of the five investigated sand filter beds. Bacteria removal in the two investigated P filters was difficult to assess because of low bacteria concentrations in the influents.

  • 11.
    Moghadas, Shahab
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Paus, Kim, H.
    Muthanna, Tone Merete
    Norwegian University of Science and Technology, Department of Hydraulic and Environment Engineering, Trondheim, Norwegian Institute for Water Research (NIVA), Trondheim.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Marsalek, Jiri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Accumulation of Traffic-Related Trace Metals in Urban Winter_Long Roadside Snowbanks2015In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 226, no 12, article id 404Article in journal (Refereed)
    Abstract [en]

    Accumulations of mass loads of selected chemicals in roadside snowbanks were studied at five sites with various traffic densities in the City of Trondheim (Norway) by collecting snow samples throughout the winter period and analysing them for 13 water quality constituents: pH, EC, alkalinity, Cl, Na, TSS, Cd, Cr, Cu. Ni, Pb, W, and Zn. The resulting dataset was then supplemented by similar data collected earlier in the City of Luleå (Sweden). Regression analyses for individual sites indicated linear trends in unit-area constituent accumulations with time (0.65

  • 12.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Treatment of phosphorus and bacteria in alkaline and sand filters used for on-site sanitation: reliminary results from a full-scale study2015In: International Terra Preta Sanitation Conference, 2015Conference paper (Refereed)
  • 13.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordqvist, Kerstin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Effect of temperature on the performance of laboratory-scale phosphorus-removing filter beds in on-site wastewater treatment2014In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 117, p. 360-366Article in journal (Refereed)
    Abstract [en]

    P-sorbing filter beds appear to be viable options for treating wastewater to reduce P discharges and recover this non-renewable resource. However, greater knowledge of filters’ responses to temperature variations is required to assess their likely performance in full-scale applications and facilitate the transfer of laboratory results to the field. Thus, in the present study two filter materials (Top16 and Polonite) were characterized physicochemically and effects of temperature on their performance were investigated under controlled laboratory conditions. Using a 22 factorial design and secondary wastewater eight filter columns were tested at temperatures of 4.3 °C and 16.5 °C. Temperature significantly (α = 0.05) and strongly affected the P binding capacity of both materials, as it was 1.2- and 1.5-fold higher at 16.5 °C than at 4.3 °C for Top16 and Polonite, respectively. This is probably due to the enhanced precipitation of calcium phosphates at higher temperature. Observed reductions in total organic carbon content in the wastewater were also positively correlated with temperature, while the pH and reduction of dissolved organic carbon remained unaffected. The physicochemical analyses indicated that several calcium phases dissolved from the filter materials, primarily gypsum and bassanite from Top16 and Portlandite from Polonite. No clear evidence of any crystalline calcium phosphates was observed in the used materials. The results clearly show that temperature strongly influences the retention of P in filters and its effects should be carefully considered before using candidate filters in full-scale applications.

  • 14.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Jourak, Amir
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Enhancing the reliability of laboratory phosphorus filter tests: effect of influent properties and interpretation of effluent parameters2014In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 225, no 1, article id 1766Article in journal (Refereed)
    Abstract [en]

    Filtration can be a convenient technique for removing phosphorus (P) at on-site wastewater treatment facilities to recycle this non-renewable element. When testing potentially suitable materials for these filters, the properties of the influent and the method used to analyse measured effluent concentrations both affect the P binding capacity determined in filter tests and therewith filter longevity predictions. At present, there is a lack of robust methods for material investigation and filter test interpretation. This study was conducted to investigate the effect of inflow PO4-P concentrations (concentration) and hydraulic surface load (load) on P binding capacity and to analyse possible interpretations of laboratory filter tests. A 22 factorial experiment with replicates was performed on the calcium-based filter material Filtra P. The investigated concentrations ranged from 12 to 50 mg L-1 and loads from 419 to 1,023 L m-2 day-1. P binding capacity (calculated by mass balance including data until PO4-P breakthrough point) was negatively affected by concentration and positively affected by load, with the effect of concentration being slightly greater. Depending on the factors' settings and on the method of evaluation (i.e. analysing all pre-saturation data or considering only pre-breakthrough results), the total measured P binding capacity varied between 2.2 and 9.0 g kg-1. The part of the breakthrough curve between the breakthrough point and saturation contributed significantly to the measured P binding capacity, and it took about three times longer for the filters to become saturated than to reach breakthrough. Furthermore, a considerable amount of P that had reacted with the filter material was washed out of the filters as particle-bound P. This indicates that it is important to determine both the PO4-P and the particle-bound P phases in the filter effluent

  • 15.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Filter beds for on-site wastewater treatment: Towards more reliable estimations of phosphorus retention2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Phosphorus (P) is an important plant nutrient and essential for life. However, thephosphate rock used for fertilizer production is a non-renewable resource and itsproduction is expected to peak. At the same time, the discharge of P into naturalwaters is causing eutrophication, a severe problem in areas such as the Baltic Sea. Onsitewastewater treatment facilities in Sweden contribute substantially to this discharge because of their inadequate retention of P. Filter beds are a potentially useful technique to capture P in on-site facilities. However, many variables need to be considered when the P retention of potential filter materials is estimated in laboratory tests prior to designing full-scale filters. The overall aim of this thesis was therefore to increase the reliability of forecasting P retention in full-scale filters by increasing the understanding of P retention in P filters under varying conditions and by identifying measures that could lead to more reliable methods of testing filter materials at laboratory scale.The effects of influent type, influent P concentration, loading rate and ambienttemperature on the filter materials Filtra P, Filtralite P, Top16 and Polonite wereinvestigated in filter column experiments using 22 factorial designs. Furthermore, the P binding mechanism was studied using mineral phase investigations and by determining the reaction time of the P in the filter. In addition, filter performance was estimated by means of hydro-geochemical transport modelling.The investigated factors significantly (Į = 0.05) affected the retention of P in the filter materials showing that it is important to consider those factors when designing laboratory filter experiments and full-scale filters. Using secondary wastewater as an influent instead of P solution decreased the P binding capacity of Filtralite P, probably due to organic compounds contained in the wastewater. Increasing influent P concentration decreased the number of bed volumes treated before breakthrough in Filtra P by 82%. The loading rate was shown to be an important design parameter. Increasing the loading rate, something commonly done in the laboratory to accelerate the testing, significantly increased the amount of washed-out particulate P in Filtra P and Filtralite P. However, the residence time was also shown to be important; it should be maximised in filter tests as far as practical constraints allow. Increasing the temperature from 4.3 to 16.5°C increased the P binding capacity in both Top16 and Polonite which was attributed to an enhanced precipitation of calcium phosphates. This indicates that results obtained from experimental filters at room temperature might overestimate filter performance in the field where the temperature can be lower. In addition, full-scale filters might function better in warm rather than cool climates. The results further showed that it is crucial to measure both the concentration of dissolved P and particulate P in the filter effluent, as P-containing particles were observed to escape from the experimental filters in this study. Hydroxylapatite was detected in the outflow hose of the Filtra P columns indicating that this mineral phase may form in the filters under certain conditions. The geochemical models, however, indicated that the only precipitated calcium phosphate compound was amorphous tricalcium phosphate.Two hydro-geochemical transport models were developed that satisfactorily described the experimentally derived P breakthrough curves and effluent pH of the filter columns with Filtralite P. The simulations suggested that calcium oxide, calcite and the calcium-silicate phase wollastonite supplied the Ca2+ and OH- ions required for the precipitation of phosphate.

  • 16.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Phosphorus Retention in Filter Beds for On-Site Wastewater Treatment: Improving the Design and Interpretation of Laboratory Filter Experiments2014Conference paper (Refereed)
  • 17.
    Jourak, Amir
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Frishfelds, Vilnis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Hellström, J. Gunnar I.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Longitudinal dispersion coefficient: effects of particle-size distribution2013In: Transport in Porous Media, ISSN 0169-3913, E-ISSN 1573-1634, Vol. 99, no 1, p. 1-16Article in journal (Refereed)
    Abstract [en]

    The effects of particle-size distribution on the longitudinal dispersion coefficient (DL) in packed beds of spherical particles are studied by simulating a tracer column experiment. The packed-bed models consist of uniform and different-sized spherical particles with a ratio of maximum to minimum particle diameter in the range of 1–4. The modified version of Euclidian Voronoi diagrams is used to discretize the system of particles into cells that each contains one sphere. The local flow distribution is derived with the use of Laurent series. The flow pattern at low particle Reynolds number is then obtained by minimization of dissipation rate of energy for the dual stream function. The value of DL is obtained by comparing the effluent curve from large discrete systems of spherical particles to the solution of the one-dimensional advection-dispersion equation. Main results are that at Peclet numbers above 1, increasing the width of the particle-size distribution increases the values of DL in the packed bed. At Peclet numbers below 1, increasing the width of the particle-size distribution slightly lowers DL.

  • 18.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Jourak, Amir
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Gustafsson, Jon Petter
    Department of Land and Water Resources Engineering, Royal Institute of Technology.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Modeling phosphate transport and removal in a compact bed filled with a mineral-based sorbent for domestic wastewater treatment2013In: Journal of Contaminant Hydrology, ISSN 0169-7722, E-ISSN 1873-6009, Vol. 154, p. 70-77Article in journal (Refereed)
    Abstract [en]

    Phosphorus filter units containing mineral-based sorbents with a high phosphate (PO4) binding capacity have been shown to be appropriate for removing PO4 in the treatment of domestic wastewater in on-site facilities. However, better understanding of their PO4 removal mechanisms, and reactions that could lead to the formation of PO4 compounds, is required to evaluate the potential utility of candidate sorbents. Models based on data obtained from laboratory-scale experiments with columns of selected materials can be valuable for acquiring such understanding. Thus, in this study the transport and removal of PO4 in experiments with a laboratory-scale column filled with a commercial silicate-based sorbent were modeled, using the hydro-geochemical transport code PHREEQC. The resulting models, that incorporated the dissolution of calcite, kinetic constrains for the dissolution of calcium oxide (CaO) and wollastonite (CaSiO3), and the precipitation of amorphous tricalcium phosphate, Ca3(PO4)2, successfully simulated the removal of PO4 observed in the experiments.

  • 19.
    Jourak, Amir
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Frishfelds, Vilnis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    The calculations of dispersion coefficients inside two-dimensional randomly packed beds of circular particles2013In: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 59, no 3, p. 1002-1011Article in journal (Refereed)
    Abstract [en]

    The longitudinal (DL) and transverse (DT) dispersion coefficients in two-dimensional (2D) randomly packed beds of circular particles in a laminar flow regime are derived. A 2D discrete system of particles is divided into cells using modified Voronoi diagrams. The relationship between the variation of the stream function and the averaged vortictiy is obtained from Computational Fluid Dynamics simulations. The whole flow pattern is then obtained by using the principle of energy dissipation rate minimization. The obtained values of DL agree well with 3D experimental data for all velocities investigated. At very high velocities, DT in 2D appears to be higher than 3D experimental data. In addition, the effects of particle size distribution, packing structure, and porosity on the DL and DT were studied. One result was that an increase in the width of the particle size distribution resulted in higher values of DL and DT at high velocities.

  • 20.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Jourak, Amir
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    The effect of hydraulic loading rate and influent source on the binding capacity of phosphorus filters2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 8Article in journal (Refereed)
    Abstract [en]

    Sorption by active filter media can be a convenient option for phosphorus (P) removal and recovery from wastewater for on-site treatment systems. There is a need for a robust laboratory method for the investigation of filter materials to enable a reliable estimation of their longevity. The objectives of this study were to (1) investigate and (2) quantify the effect of hydraulic loading rate and influent source (secondary wastewater and synthetic phosphate solution) on P binding capacity determined in laboratory column tests and (3) to study how much time is needed for the P to react with the filter material (reaction time). To study the effects of these factors, a 22 factorial experiment with 11 filter columns was performed. The reaction time was studied in a batch experiment. Both factors significantly (α = 0.05) affected the P binding capacity negatively, but the interaction of the two factors was not significant. Increasing the loading rate from 100 to 1200 L m-2 d-1 decreased P binding capacity from 1.152 to 0.070 g kg-1 for wastewater filters and from 1.382 to 0.300 g kg-1 for phosphate solution filters. At a loading rate of 100 L m-2 d-1, the average P binding capacity of wastewater filters was 1.152 g kg-1 as opposed to 1.382 g kg-1 for phosphate solution filters. Therefore, influent source or hydraulic loading rate should be carefully controlled in the laboratory. When phosphate solution and wastewater were used, the reaction times for the filters to remove P were determined to be 5 and 15 minutes, respectively, suggesting that a short residence time is required. However, breakthrough in this study occurred unexpectedly quickly, implying that more time is needed for the P that has reacted to be physically retained in the filter.

  • 21.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Jourak, Amir
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Flow design of phosphorus filters2012Conference paper (Refereed)
  • 22.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Jourak, Amir
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Phosphorus binding to Filtra P in batch tests2012In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 33, no 9, p. 1013-1019Article in journal (Refereed)
    Abstract [en]

    Recent guidelines from the Swedish Environmental Protection Agency recommend stricter regulations for phosphorus (P) reduction in small-scale wastewater treatment, which raises the need for additional and novel treatment steps in small-scale facilities. Following a biological pre-treatment, filter systems can be a convenient option. In this study, the P binding capacity of the filter material Filtra P was investigated in batch tests. The batch test method was evaluated with respect to the effects of liquid-to-solid ratio and particle size on P binding capacity. For initial concentrations (ci ) between 3 and 100 mg L−1, the P in the solution was completely and rapidly bound to the material, indicating that Filtra P was an efficient substrate for this process. The maximum amount of bound P was 4.3 ± 0.64 g kg−1 at c i = 300 mg L−1. P binding capacity and turbidity measured in the supernatant correlated positively. Turbidity was probably caused by calcium-P-precipitates suggesting precipitation was the major removal mechanism. Neither liquid-to-solid ratio, nor particle size, affected P binding capacity significantly (α = 0.05) at ci  = 1000 mg L−1, confirming that the conditions used in the batch tests were appropriate. In full-scale applications, the precipitate formed may be at risk of being washed out of the filter, leading to low total P reduction and recovery.

  • 23.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Phosphorus fluxes and recovery options in the wastewater system of the city of Luleå, Northern Sweden2012Conference paper (Refereed)
    Abstract [en]

    Phosphorus fluxes in Sweden’s municipal wastewater systems are barely known today and phosphorus recovery is poor in many systems. Further, there are about one million on-site treatment facilities, of which a majority has a low phosphorus capturing potential. There is a need to identify phosphorus losses and recovery options in the systems to increase phosphorus recovery both on centralised and decentralised level. This study focuses on the municipality of Luleå, northern Sweden. Luleå’s sanitary system is partly centralised (discharging to a WWTP with a moving bed biofilm reactor and chemical phosphorus precipitation) and partly decentralised (with several small-scale or on-site treatment facilities). The aim of this study is to identify and quantify phosphorus fluxes, including phosphorus recovery rates and losses, in the municipality’s existing sanitary system. Furthermore, alternative and innovative sanitary systems are analysed towards their phosphorus fluxes and recovery options. The study therefore contributes to more sustainable sanitation systems

  • 24.
    Jourak, Amir
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Frishfelds, Vilnis
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Modeling of phosphate removal by fitra P in fixed-bed columns2011In: 2nd International Conference on Environmental Science and Technology , ICEST 2011 / [ed] Saji Baby; Bogdan Zygmunt, China, 2011, Vol. 2, p. 241-248Conference paper (Refereed)
    Abstract [en]

    Hydropower still faces complex scientific and technical challenges in order to secure the availability and reliability of the power plants despite more than a century of development. The main challenge is due to new market constrains such as electrical market deregulation and introduction of renewable sources of energy. The major problem is related to the dynamic of the rotor involving several fields: hydraulics, power engineering and mechanics. On the other side, the large and growing hydropower world market represents an opportunity for technically advanced companies offering better efficiency. The difficulty to scale rigorously any technical advance makes full-scale experiment a necessity. World unique facilities are available at Porjus, Sweden, for this purpose. The Porjus Hydropower Centre is composed of a Francis (U8) and a Kaplan (U9) turbine of 10 MW, each exclusively dedicated to education, research and development. In order to further investigate specific issues related to availability and reliability, a project was initiated in 2006. The main objective is to make U9 a full-scale hydropower laboratory able firstly to furnish the necessary data for the development of rotor-dynamic models but also turbines and bearings. To this purposes more than 200 sensors have been installed to measure displacements, forces, pressure, film thickness, strains... The work presents an overview of the newly upgrade facility as well as some of the problems faced during the instrumentation of the machine.

  • 25.
    Jourak, Amir
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Frishfelds, Vilnis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    The calculations of dispersion coefficients inside two-dimensional randomly packed beds of circular particles2011Conference paper (Refereed)
  • 26. Diener, Silvia
    et al.
    Andreas, Lale
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ecke, Holger
    Lagerkvist, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Accelerated carbonation of steel slags in a landfill cover construction2010In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 30, no 1, p. 132-139Article in journal (Refereed)
    Abstract [en]

    Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.e. carbonation, exerted by five different factors resembling both the material characteristics and the environmental conditions is investigated. Leaching behaviour, acid neutralization capacity and mineralogy (evaluated by means of X-ray diffraction, XRD, and thermogravimetry/differential thermal analysis, TG/DTA) are tested after different periods of ageing under different conditions.Samples aged for 3 and 10 months were evaluated in this paper. Multivariate data analysis was used for data evaluation. The results indicate that among the investigated factors, ageing time and carbon dioxide content of the atmosphere were able to exert the most relevant effect. However, further investigations are required in order to clarify the role of the temperature.

  • 27.
    Jourak, Amir
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Frishfelds, Vilnis
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Modelling of phosphate removal by Filtrap in a fixed-bed column2010Conference paper (Other academic)
  • 28.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Diener, Silvia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andreas, Lale
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lind, Lotta
    Steel slag used in landfill cover liners: laboratory and field tests2010In: Waste Management & Research, ISSN 0734-242X, E-ISSN 1096-3669, Vol. 28, no 12, p. 1114-1121Article in journal (Refereed)
    Abstract [en]

    Stricter rules for landfilling within the EU have led to the closure of many landfills and a need for large amounts of cover liner materials. Therefore, the potential utilization of mixtures of electric arc furnace slag (EAFS) and ladle slag (LS), which are currently deposited in landfills, as a material for use as landfill liner was investigated. Laboratory analyses showed the mixtures to have similar compression strength to that of high-strength concrete and low hydraulic conductivity (<10-11 m s-1 in some cases). However, both their hydraulic conductivity and compaction properties were strongly affected by the time between adding water to the mixtures and compacting them (tests showed that a delay of 24 h can lead to an increase in hydraulic conductivity, so it should be compacted as soon as possible after mixing the material with water). In addition, the performance of a cover liner constructed using EAFS and LS was studied in a 2-year field trial on a landfill for municipal solid waste, in which the average amount of leachate collected from ten lysimeters was only 27 L m-2 year-1, easily meeting Swedish criteria for the permeability of covers on non-hazardous waste landfills (≤50 L m-2 year-1). Thus, the material seems to have promising potential for use in barrier constructions.

  • 29.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Svensson, Malin
    Ecke, Holger
    Kumpiene, Jurate
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Maurice, Christian
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andreas, Lale
    Lagerkvist, Anders
    Hydraulic conductivity of fly ash: sewage sludge mixes for use in landfill cover liners2009In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 43, no 14, p. 3541-3547Article in journal (Refereed)
    Abstract [en]

    Secondary materials could help meeting the increasing demand of landfill cover liner materials. In this study, the effect of compaction energy, water content, ash ratio, freezing, drying and biological activity on the hydraulic conductivity of two fly ash - sewage sludge mixes was investigated using a 27-1 fractional factorial design. The aim was to identify the factors that influence hydraulic conductivity, to quantify their effects and to assess how a sufficiently low hydraulic conductivity can be achieved. The factors compaction energy and drying, as well as the factor interactions material×ash ratio and ash ratio×compaction energy affected hydraulic conductivity significantly (α = 0.05). Freezing on 5 freeze-thaw cycles did not affect hydraulic conductivity. Water content affected hydraulic conductivity only initially. The hydraulic conductivity data were modelled using multiple linear regression. The derived models were reliable as indicated by R2adjusted values between 0.75 and 0.86. Independent on the ash ratio and the material, hydraulic conductivity was predicted to be between 1.7 × 10-11 m s-1 and 8.9 × 10-10 m s-1 if the compaction energy was 2.4 J cm-3, the ash ratio between 20 and 75 % and drying did not occur. Thus, the investigated materials met the limit value for non-hazardous waste landfills of 10-9 m s-1.

  • 30.
    Jourak, Amir
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, Staffan
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Modelling of the transport of substances through reactive porous materials2009In: Svenska mekanikdagarna: Södertälje 2009, Svenska nationalkommittén för mekanik , 2009, p. 102-Conference paper (Other academic)
  • 31.
    Diener, Silvia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andreas, Lale
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Herrmann, Inga
    Ecke, Holger
    Lagerkvist, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Accelerated carbonation of ashes and steel slags in a landfill cover construction2008In: Proceedings of Second International Conference on Accelerated Carbonation for Environmental and Materials Engineering / [ed] Renato Baciocchi; Giulia Costa; Alessandra Polettini; Raffaella Pomi, University of Rome "La Sapienza" , 2008, p. 389-400Conference paper (Refereed)
    Abstract [en]

    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.

  • 32. Diener, Silvia
    et al.
    Andreas, Lale
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Lagerkvist, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Results from a field study using steel industry slags in a landfill cover construction2008Conference paper (Other academic)
  • 33.
    Diener, Silvia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andreas, Lale
    Herrmann, Inga
    Lagerkvist, Anders
    Mineral transformations in steel slag used as landfill cover liner material2007In: SARDINIA 2007: Eleventh International Waste Management and Landfill Symposium ; [1 - 5 October 2007, S. Margherita di Pula, Cagliari, Sardinia, Italy] / [ed] Raffaello Cossu, Cagliari: CISA, Environmental Sanitary Engineering Centre , 2007, Vol. 1Conference paper (Refereed)
    Abstract [en]

    In Europe, 15.2 million tonnes of steel slags have been generated in 2004 (Euroslag, 2006) out if which almost 6 million tonnes came from electric arc furnace (EAF) steelmaking and secondary metallurgical processes. In the presented project from Luleå University of Technology, two types of EAF slag and one slag originating from secondary metallurgical processes named ladle slag are investigated. The chemical and physical properties of these slags have been studied in detail (Herrmann, 2006; Andreas et al., 2005). For utilising steel slags in the liner of a landfill cover the long-term stability of the minerals is of great importance. Therefore, the ageing of steel slag minerals is evaluated with the help of a laboratory experiment. Particularly, the research questions, the experimental set-up and the methodology are presented. The present paper is part of a research project of the Division of Waste Science and Technology at Luleå University of Technology, Sweden in cooperation with Uddeholm Tooling AB, Hagfors municipality and MiMeR (Mineral and Metal Recycling Research Centre). It is investigated if steel slags are stable as a landfill cover liner material. The long-term stability is evaluated by determining the factors influencing the mineralogy of the slags and possible mineral transformations through ageing under the environmental conditions in a liner. The experiment includes two similar types of EAF slag and one ladle slag. Each steel slag sample is made by mixing 50% EAF slag and 50% ladle slag, addition of water and compaction. The specimens are stored in boxes under different atmospheric conditions. A reduced multivariate design has been chosen to determine the impact of different factors on the slag mineralogy. The factors that are varied in the experiment are relative humidity, carbon dioxide and temperature of the atmosphere surrounding the slag material as well as ageing time and the quality of the water used for sample making (see table 1). Table 1. Factorial design for ageing experiment of steel slagsLowMiddleHighRelative humidity30% -100%Carbon dioxide content0.036 (air)20 % * 100 %Temperature5 °C30 °C60 °CTime 1 month6 months1 yearWater quality destilled water -LeachateThe ageing of minerals is expected to initiate mineral transformations in steel slags. Primary phases will alter into secondary mineral phases. Changes in mineralogy can influence the stability of the liner. To evaluate mineralogy and properties of the aged steel slag, different analyses will be performed after the storage time of the specimens. X-ray diffraction and scanning electron microscopy as well as shear strength, acid neutralisation capacity and cation exchange capacity will be included. A possible mineral transformation for an alkaline material as steel slags can be the reaction of calcium ions from calcium silicates with the carbon dioxide resulting in the precipitation of calcium carbonate. Through this carbonation reaction, the transport of carbon dioxide into the bulk of the specimen could be hindered by the reaction products. Therefore, surface morphology can influence mineral transformations. First results and evaluations will be presented at the conference. REFERENCES Andreas L., Herrmann I., Lidstrom-Larsson M. & Lagerkvist A. (2005) Physical properties of steel slag to be reused in a landfill cover, Sardinia 2005, Tenth International Waste Management and Landfill Symposium, S. Margherita di Pula, Cagliari, Italy; 3 - 7 October 2005Euroslag (2006) Legal status of Slags. Position Paper. January 2006. The European Slag Association - EUROSLAG. Duisburg, Germany.Herrmann I. (2006). Use of Secondary Construction Material in Landfill Cover Liners. Licentiate Thesis. Luleå University of Technology, Sweden.

  • 34.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Aktivitet: Miljöriktig användning av askor, Värmeforsk2006Conference paper (Other (popular science, discussion, etc.))
  • 35.
    Todorovic, Jelena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Svensson, Malin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ecke, Holger
    Artificial carbonation for controlling the mobility of critical elements in bottom ash2006In: Journal of Material Cycles and Waste Management, ISSN 1438-4957, E-ISSN 1611-8227, Vol. 8, no 2, p. 145-153Article in journal (Refereed)
    Abstract [en]

    In municipal solid waste incineration (MSWI), bottom ash, generated at a stoker grate type incinerator, the critical elements were identified in terms of EU regulation. The stabilizing effect of moderate carbonation (pH 8.28 ± 0.03) on critical contaminants was studied through availability and diffusion leaching protocols. Data from the performed tests were evaluated with the goal of reusing MSWI bottom ash as secondary construction material. To investigate the mobilizing effect of CO2, suspended MSWI bottom ash was severely carbonated (pH 6.40 ± 0.07). The effect of CO2 and its interaction with other leaching factors, such as liquid/solid (L/S) ratio, leaching time, pH, ultrasound treatment, and leaching temperature, were examined using a reduced 26-1 experimental design. Contaminants identified as critical were Cr, Cu, Mo, Sb, Cl-, and SO4 2-. Although moderate carbonation decreased the release of Cr, Cu, Mo, and Sb from compacted bottom ash, the main disadvantage remains its inability to demobilize Cl- and SO4 2-. The hypothesized mobilizing effect of severe carbonation was proven. The treatment enhanced the separation of critical components (α = 0.05) (except for Cl-), i.e., about fivefold for Sb and about twofold for Cr, Cu, and S. Nevertheless, the prospect is good that severe carbonation could constitute the deciding key parameter to facilitate the technical feasibility of a future washing process for MSWI bottom ash.

  • 36.
    Diener, Silvia
    et al.
    Dresden University of Technology.
    Andreas, Lale
    Herrmann, Inga
    Lagerkvist, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lidström-Larsson, Margareta
    Mineral phases in steel industry slags used in a landfill cover constuction2006In: Abstract proceedings of the 4th Intercontinental Landfill Research Symposium, , [June 14th to 16th 2006, Gällivare, Sweden] / [ed] Anders Lagerkvist, Luleå: Luleå tekniska universitet, 2006, p. 73-74Conference paper (Other academic)
  • 37. Herrmann, Inga
    et al.
    Andreas, Lale
    Lidström-Larsson, Margareta
    Ecke, Holger
    Lagerkvist, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Reuse of steel industry slag in a landfill top cover2006In: Abstract proceedings of the 4th Intercontinental Landfill Research Symposium, [June 14th to 16th 2006, Gällivare, Sweden] / [ed] Anders Lagerkvist, Luleå: Luleå tekniska universitet, 2006, p. 88-89Conference paper (Other academic)
  • 38.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Use of sedondary construction material in landfill cover liners2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The applicability of fly ash - sewage sludge and steel slag mixtures in landfill cover liners was investigated putting special emphasis on the hydraulic conductivity (HC) of the materials. The objective was to identify the factors significantly affecting the HC of the materials and to quantify their effects using multiple linear regression (MLR). It was discussed what impact low-HC liners might have on the landfill system and the environment. Although mainly affected by the COMPACTION ENERGY used, the HC of the fly ash - sewage sludge samples were also affected by DRYING and the factor interactions MATERIAL×ASH RATIO and ASH RATIO×COMPACTION ENERGY. The models derived using multiple linear regression could be used to predict an HC between 1.7×10-11 m s-1 and 9.5×10-10 m s-1, if a compaction energy of 2.4 J cm-3 was applied and no drying occurred. TIME between the addition of water and compaction mainly affected the HC of the steel slag samples. The HC of the steel slag mixtures was between 10-8 and 10-12 m s-1 if they were compacted immediately after water addition. The HC showed a decreasing trend during the measurement period of 53±1 days. It was suspected that cement reactions in the material influenced HC. Low-HC liners are a potential environmental hazard. Monitoring of landfill emissions is prescribed for about 30 years though contaminated landfill leachate is generated for at least one human generation. As the failing of the liner can go along with a sudden increase of leachate release from the landfill and thus with severe environmental pollution, the concept of applying low-HC liners needs to be reconsidered.

  • 39. Ecke, Holger
    et al.
    Svensson, Malin
    Todorovic, Jelena
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Artificial carbonation for controlling the mobility of critical elements in incineration residues2005In: Waste Management in the Focus of Controversial Interests: 1st BOKU Waste Conference 2005 / [ed] Peter Lechner, Facultas Universitätsverlag , 2005Conference paper (Refereed)
  • 40. Herrmann, Inga
    et al.
    Andreas, Lale
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lidström-Larsson, Margareta
    Lagerkvist, Anders
    Physical properties of steel slag to be reused in a landfill cover2005In: SARDINIA 2005: Tenth International Waste Management and Landfill Symposium ; S. Margerita di Pula, Sardinia, Italy, 3 - 7 October 2005 / [ed] Raffaello Cossu, Cagliari: CISA, Environmental Sanitary Engineering Centre , 2005Conference paper (Refereed)
  • 41. Herrmann, Inga
    et al.
    Andreas, Lale
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lidström-Larsson, Margareta
    Gustafsson, G.
    Reuse of steel industry slags in landfill top cover constructions2005In: Securing the future: international conference on mining and the environment, metals and energy recovery : proceedings, Stockholm: SweMin , 2005, p. 409-416Conference paper (Other academic)
  • 42. Svensson, Malin
    et al.
    Herrmann, Inga
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Ecke, Holger
    Sjöblom, Rolf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Selektiv mobilisering av kritiska element hos energiaskor2005Report (Other academic)
    Abstract [sv]

    SMAK syftade till att undersöka möjligheterna att selektivt separera element med hög mobilitet i botten- och flygaska. I faktordesignade extraktionsförsök identifierades de faktorer som har en signifikant och avgörande inverkan på elementens mobilitet. Försöken stöddes av kemiska jämviktsberäkningar med PHREEQC-2. Den optimala faktorinställningen användes sedan för att bedöma askans behandling enligt den kommande EU-lagstiftningen samt avfallsförordningen, Naturvårdsverkets generella riktvärden för förorenad mark och kemikalineinspektionens föreskrifter. Målet är att erhålla en produkt som på ett robust och ekonomiskt sätt kan omhändertas och helst återanvändas. Dessa behandlingar visade sig dock inte förändra botten- eller flygaskans klassificering enligt Rådets beslut om acceptanskriterier vid deponering.

  • 43.
    Nyström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordqvist, Kerstin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Laboratory evaluation of coagulants for treatment of urban snowmeltManuscript (preprint) (Other academic)
    Abstract [en]

    The treatment effect and process characteristics of coagulation were investigated in urban snow at laboratory scale using jar tests. An initial screening of twelve coagulants and flocculant aids was carried out to find a selection of chemicals that efficiently reduced turbidity and suspended solids. Five coagulants were then further investigated and additional parameters measured (conductivity, alkalinity and ζ-potential). The urban snowmelt mixture was characterized by high, but variable, particle content and low alkalinity. In the jar tests, high treatment efficiency (>90% reduction of both turbidity and suspended solids) was achieved for all coagulants. For very low alkalinity waters, the use of a biopolymer such as chitosan may be advantageous due to minimal alkalinity consumption. Based on the occurrence of charge reversal for all chemicals investigated, the mechanism for coagulation was likely charge neutralization. Treatment effect occurred in the ζ-potential range of -14 to +1 mV depending on the coagulant used. Initial turbidity and the ζ-potential are interesting parameter candidates for dosing control in stormwater treatment applications.

  • 44.
    Nyström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordqvist, Kerstin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Herrmann, Inga
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Removal of metals and hydrocarbons from urban snowmelt by coagulation and flocculationManuscript (preprint) (Other academic)
    Abstract [en]

    The treatment efficiency of a coagulation/flocculation and sedimentation process was investigated in urban snowmelt. Five different coagulants were evaluated for their effectiveness in reduction of particle content, organic carbon, total and dissolved metals, hydrocarbon oil index, PAHs and if any changes occurred in the particle size distribution. The pollutants in the snow melt were mostly in the particulate phase, and for both oil index and PAHs characterized by the larger sized molecules. An iron chloride coagulant was the only coagulant that had an effect on the particle size distribution post-treatment, where the distribution was shifted towards larger particles. In terms of total metal removal, the performance for the coagulants were similar with above 90% removal on average. Dissolved Cu, was one of the metals found in the dissolved phase, and it was reduced by 40% by coagulation treatment. The iron chloride coagulant did increase the dissolved Zn, attributed to a larger drop in pH resulting in a higher ion mobility. Similarly, the reduction in organic content, both TOC/oil/PAH were above 90% for most coagulants.

1 - 44 of 44
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