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  • 1.
    Amofah, Lea Rastas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Mattsson, Jonathan
    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.
    Willow bed fertigated with domestic wastewater to recover nutrients in subarctic climates2012In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 47, p. 174-181Article in journal (Refereed)
    Abstract [en]

    Conventional methods for wastewater treatment emphasise protecting human health, receiving waters and the environment. Consequently, they are generally designed to reduce pollutant levels and are not well-suited for creating resources. This paper describes a new, more sustainable and energy-efficient approach to wastewater treatment that satisfies health and environmental standards while also facilitating resource recovery. A full-scale compact willow bed was intensively fertigated with domestic wastewater in a cold climate to examine biomass production, the recovery of nutrients in willow biomass, and wastewater treatment. The performance of the willow bed was assessed for two years, covering three growing seasons. The studied frost-tolerant willow clones produced good biomass yields per unit area (6–7 ton dry matter/ha and year) under intensive fertigation with dense planting and continuous harvesting. The biomass yield of willow species exhibiting vertical growth seemed to be greater than that for lateral growth species in the dense stands studied. In contrast to biomass production, nutrient recovery was facilitated by intensive fertigation, continuous harvesting and less dense planting with a horizontally growing willow clone. The estimated nitrogen accumulation in above-ground biomass was 210 kg/ha and that of phosphorus was 30 kg/ha. 90% of the accumulated nutrients in the above-ground biomass were removed from the site during the experimental period. However, the quantity of nutrients accumulated in the willow biomass represented only a small fraction of the loaded or removed amount. The willow bed was shown to be an efficient prefilter for reducing the abundance of particulate and organic matter, leaving the bulk of the remaining nutrients in forms that could be recovered in subsequent treatment steps.

  • 2. Andersson-Chan, Anneli
    et al.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    VVS 2000: tabeller och diagram : Vatten- och avloppsteknik2004Book (Other (popular science, discussion, etc.))
  • 3.
    Andersson-Wikström, Alexandra
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Österlund, Helene
    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.
    The release of pollutants from roofing materials in laboratory experiments2015Conference paper (Refereed)
    Abstract [en]

    Diffuse pollution sources have been recognised by the European Water Framework Directive to significantly contribute to pollution of stormwater receivers. Stormwater runoff is considered to represent diffuse pollution sources. The aim of this study was to clarify the contributions of specific sources in the urban environment to the content of organic and inorganic pollutants in stormwater. This was done by conducting laboratory screening tests of several conventional roofing materials and coatings to determine which pollutants they release and how they might contribute to the deterioration of stormwater quality. The studied pollutants include metals (Cd, Cr, Cu, Ni, Pb, V, Zn) as well as polycyclic aromatic hydrocarbons (PAHs), phthalates, pesticides, nonylphenols and –ethoxylates. Many of the studied roofing materials, e.g. roofing shingle, a PVC sheet and a bitumen paste for felt roof maintenance, exhibited the potential to release several of these substances into stormwater runoff. However, phthalates were not released from any of the studied materials under the tested conditions. In addition, quite similar materials exhibited rather different substance release profiles.

  • 4. Blecken, Godecke-Tobias
    et al.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Svensson, Gilbert
    Hedström, Annelie
    Fat, oil and grease (FOG) in sewer systems: a significant problem in Sweden and Norway2009Conference paper (Other academic)
  • 5.
    Blecken, Godecke-Tobias
    et al.
    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.
    Svensson, Gilbert
    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.
    Fett i avloppsnät: kartläggning och åtgärdsförslag2010Report (Other academic)
    Abstract [en]

    Fat oil and grease (FOG) from food preparation can cause severeproblems if it is discharged to the municipal sewer network. A surveyamong Swedish and Norwegian municipalities has shown that nearlyall respondents experience FOG-related problems. The most commonproblem is FOG accumulation connected to the sewer pipes whichdecreases the pipe pipe capacity and may lead to sewer overflows. FOGaccumulation occurs especially at lift stations and depressions. FOGdeposits are often made up of saponised FOG. The fatty acids promotefurthermore corrosion of concrete pipes. FOG can even impact wastewater treatment and might cause severer working conditions.The aim for the water suppliers has thus to be an effective FOGsource control before FOG is discharged to the sewer network. Sourcesare both commercial establishments and residential sewer customers.In this report different source control measures are discussed. Greaseinterceptors are commonly used for commercial FOG sources. However,a number of them lack a grease interceptor and quite often operationand maintenance is deficient. An insufficient frequency ofemptying and a lack of supervision have been identified as a commonproblem. FOG collection systems for commercial FOG producers existin both Sweden and Norway. Collection systems for private householdsare currently in a test phase and experiences from among others Austriaare promising. Even the collected amount of FOG could presumablybe increased. Collected FOG and FOG slurry from interceptors is avaluable resource which can be used as raw material in the chemicalindustry or as an energy source (combustion, biodiesel, fermentation).Threshold values for FOG discharges are set up commonly by municipalities.However, even here supervision is often insufficient. Often, thethreshold values are inadequately low and a value of at least 150 mg/lis recommended. All those measures have to be supported by informationcampaigns which aim on both commercial and private customers.

  • 6.
    Blecken, Godecke-Tobias
    et al.
    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.
    Svensson, Gilbert
    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.
    Projekt: Fett i avloppsnät - Kartläggning och åtgärdsförslag2010Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Matfett och -olja som släpps ut till avloppsnätet kan orsaka driftproblem. Denna enkätstudie har visat att nästan alla kommuner i Norge och Sverige upplever problem på grund av fettet.

  • 7.
    Blecken, Godecke-Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Zinger, Yaron
    Facility for Advancing Water Biofiltration, Department of Civil Engineering, Monash University.
    Deletic, Ana
    Facility for Advancing Water Biofiltration, Department of Civil Engineering, Monash University.
    Fletcher, Tim
    Facility for Advancing Water Biofiltration, Department of Civil Engineering, Monash University.
    Hedström, Annelie
    Viklander, Maria
    Laboratory study on stormwater biofiltration: nutrient and sediment removal in cold temperatures2010In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 394, no 3-4, p. 507-514Article in journal (Refereed)
    Abstract [en]

    Stormwater biofilters have the ability to remove nutrients from stormwater. Reliable pollutant removal during the cold season is particularly important due to the comparably high contamination levels. However, the removal performance might be negatively affected by low temperatures. A biofilter column study was conducted in thermostat-controlled climate rooms (at 2, 7 and 20 °C) to investigate the effect of low temperatures on nutrient removal. Phosphorus and suspended solids removal were significantly correlated and consistently very high (typically in excess of 90 and 95%, respectively, at all temperatures). This is important for the successful implementation of biofilters in cold climates since phosphorus is commonly of principal concern, often being the limiting factor for eutrophication in freshwater ecosystems. Unfortunately, nitrogen removal was poor and leaching was shown, which increased with temperature. The increasing nitrate-nitrogen production rates with temperature were well described by the Arrhenius relationship with temperature coefficients Q10 in the range which is typically used to describe temperature effects on nitrification. Thus, temperature effects have to be considered when nitrogen removal is targeted and the biofilter might be exposed to cold temperatures.

  • 8.
    Cettner, Annicka
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ashley, Richard
    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.
    Assessing receptivity for change in urban stormwater management and contexts for action2014In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 146, p. 29-41, article id 13Article in journal (Refereed)
    Abstract [en]

    Individual and organisational receptivity for change towards the use of sustainable stormwater management systems has been previously examined, but the significance of the different contexts for achieving this has been largely unexplored. This paper examines the significance of contexts associated to the actions to bring this about by proposing and evaluating an emerging framework based on two related receptivity theories: the individual or organisational approach and the contextual approach. Results from a Swedish national questionnaire with professionals in stormwater management have been used, together with a limited number of interviews to develop and understand the validity of the framework. The analysis has indicated that the respondents were professionally prepared for change (action) but not practically prepared due to inadequate supportive contexts. In response, a number of potential contexts associated to the necessary actions were identified. The framework was found to provide new insights into the influence of receptive contexts for a change in water management practice. These insights can be used by policy makers and others to better support the realization of professional openness for change and thus accelerate the process of change to sustainable stormwater practice.

  • 9.
    Cettner, Annicka
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ashley, Richard
    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.
    Sustainable development and urban stormwater practice2014In: Urban Water Journal, ISSN 1573-062X, Vol. 11, no 3, p. 185-197Article in journal (Refereed)
    Abstract [en]

    The traditional use of piped systems for stormwater management is increasingly criticized as being ‘unsustainable’. These systems are part of the water domain where much research has focused on sustainable development indicators to support decision-makers in selecting systems that are more sustainable. However, the interest in sustainable development indicators is low. This paper identifies conditions to engage the practitioners to inform their actions in regard to sustainable stormwater management. Empirical evidence has been obtained from interviews with water professionals from Swedish municipalities. The environmental-technical discourse of sustainable stormwater development is a strong barrier in the change process, to the neglect of the social aspects. In the interviews, reframing the discourse was possible in visions of future sustainable stormwater systems embracing green infrastructure. In action, primary conditions can support sustainable pathways in realizing this vision. The paper suggests further incentives for increased implementation of non-structural measures by developing the identified conditions.

  • 10.
    Garmabaki, Amir Soleimani
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Marklund, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Thaduri, Adithya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Underground pipelines and railway infrastructure: failure consequences and restrictions2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    Abstract [en]

    Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures can entail critical consequences for society and industry, resulting in direct and indirect costs for all the stakeholders involved. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within the transportation infrastructure. The aim of this study has been to identify failure modes and consequences related to pipelines crossing railway corridors. Expert opinions have been collected through interviews and two sets of questionnaires have been distributed to the 291 municipalities in Sweden, with 137 responses in total. The failure analysis has revealed that pipe deformation has the highest impact, followed by pipe rupture at locations where pipelines cross railway infrastructure. For underground pipelines under railway infrastructure, ageing and the external load were awarded a higher ranking than other potential causes of pipeline failure.

  • 11.
    Garmabaki, Amir Soleimani
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Marklund, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Thaduri, Adithya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Underground pipelines and railway infrastructure: failure consequences and restrictions2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    Abstract [en]

    Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures can entail critical consequences for society and industry, resulting in direct and indirect costs for all the stakeholders involved. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within the transportation infrastructure. The aim of this study has been to identify failure modes and consequences related to pipelines crossing railway corridors. Expert opinions have been collected through interviews and two sets of questionnaires have been distributed to the 291 municipalities in Sweden, with 137 responses in total. The failure analysis has revealed that pipe deformation has the highest impact, followed by pipe rupture at locations where pipelines cross railway infrastructure. For underground pipelines under railway infrastructure, ageing and the external load were awarded a higher ranking than other potential causes of pipeline failure.

    Authors gratefully acknowledge the funding provided by Sweden’sinnovation agency, Vinnova, through the strategic innovation programmeInfraSweden2030. The funding was granted in a competitiveapplication process that assessed replies to an open call for proposalsconcerning “Condition Assessment and Maintenance of TransportInfrastructure (Grant No. 2016-033113)”.

    Authors gratefully acknowledge the technical support and collaboration(In-kind support) of Arrsleff R€orteknik at Sweden, Luleå RailwayResearch Center (JVTC), Stormwater&Sewers and the SwedishTransport Administration (Trafikverket). In addition, the authors arethankful to the anonymous referees for their constructive commentsand Dr Matthias Asplund and Dr Masoud Naseri for their support andsuggestions.

  • 12.
    Garmabaki, Amir Soleimani
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Thaduri, Adithya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Marklund, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Odelius, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Bansal, Tarun
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Rantatalo, Matti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Asplund, Matthias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Indahl, Stefan
    A Survey on Underground Pipelines and Railway Infrastructure at Cross-Sections2019In: ESREL-2019 / [ed] Michael beer, Enrico Zio, 2019Conference paper (Refereed)
    Abstract [en]

    Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures are critical for society and industry resulting in direct and indirect costs for all the related stakeholders. Pipeline failures are complex processes, which are affected by many factors, both static (e.g., pipe material, size, age, and soil type) and dynamic (e.g., traffic load, pressure zone changes, and environmental impacts). These failures have serious impacts on public due to safety, disruption of traffic, inconvenience to society, environmental impacts and shortage of resources. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within transportation infrastructure. The aim of this study is to identify failure modes and consequences related to the crossing of pipelines in railway corridors. Expert opinion have been collected through two set of questionnaires which have been distributed to the 291 municipalities in the whole Sweden. The failure analysis revealed that pipe deformation has higher impact followed by pipe rupture at cross-section with railway infrastructure. For underground pipeline under railway infrastructure, aging and external load gets higher ranks among different potential failure causes to the pipeline.

  • 13. Hanaeus, Jörgen
    et al.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hellström, Daniel
    Stockholm Vatten AB.
    Bäckström, Magnus
    Exergianalys som verktyg inom VA-tekniken2003Report (Other academic)
    Abstract [sv]

    Exergianalys är ett värderingssätt som ger ett mått på förbrukning av ordnade strukturer och kan ses som ett komplement till ekonomiska analyser. Exergianalysen kräver en klar avgränsning av det system som ska utvärderas. I denna rapport ges tre exempel på hur exergikalkyler kan nyttjas i VA-sammanhang. Slutligen diskuteras exergikalkylernas begränsningar och möjligheter

  • 14.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Adsorption and reclamation of wastewater nitrogen and the value of human urine as a nitrogen fertiliser2000Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ammonium adsorption and ammonium ion exchange technique are possible alternatives for ammonium reclamation at conventional wastewater treatment plants. There are a few ion exchange applications that have been suggested for nitrogen reclamation, which can be further developed. It was indicated that a small amount of ammonium was adsorbed to sand due to a low adsorption capacity. It seemed, however, as the adsorption capacity was not completely utilised during the warm seasons when employing wastewater infiltration systems. An increased adsorption would, therefore, not automatically have a significant impact on the nitrogen retention; this due to the weak binding between the ammonium ions and sand grains. When comparing human urine with commercial fertilisers and green manure crops as nitrogen fertilisers, it was indicated that utilising human urine regenerated the lowest net exergy consumption. The distance of the urine transports had a great impact on the exergy consumption.

  • 15.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Ion exchange of ammonium in zeolites: a literature review2001In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 127, no 8, p. 673-681Article in journal (Refereed)
    Abstract [en]

    The objective of this review was to acquire knowledge concerning the ammonium ion exchange technique within the field of wastewater treatment. General concepts as well as details concerning the loading and the regeneration phases were included. Both chemical and biological regeneration processes were reviewed. Concerning ion exchangers, the study focused on different kinds of zeolites. The possibilities of employing the ion exchange technique for the recovery of nitrogen was also discussed. The study was carried out as a literature review. Conclusions from this study are that full-scale wastewater treatment plants that employ the ammonium ion exchange technique are scarce and few applications have been developed to recover ammonia nitrogen, for example, for agricultural purposes. Zeolites are somewhat heterogeneous because of natural variations of the minerals. Factors that influence the ammonium adsorption during the loading phase are well known. Biological regeneration has primarily been developed to decrease the brine consumption at regeneration or to improve the conventional nitrification-denitrification process. If the ion exchange technique is to be used to recover ammonium, both chemical and biological regeneration might be employed.

  • 16.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nitrogen conversion processes when treating wastewater in soil systems: the importance of ammonium adsorption2000In: Vatten, ISSN 0042-2886, Vol. 56, no 2, p. 85-95Article in journal (Other academic)
  • 17.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Reactive filter materials for ammonium and phosphorus sorption in small scale wastewater treatment2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Existing small scale wastewater treatment systems in Nordic countries have generally low treatment efficiency regarding phosphorus and nitrogen. Even though only 15% of the Swedish population is connected to on-site wastewater treatment systems, the total discharge of phosphorus from these systems exceeds the total discharge from all municipal treatment plants in Sweden. The overall objective of this thesis was to investigate certain components of small wastewater treatment systems that improve the effluent quality and facilitate the recovery of wastewater phosphorus and nitrogen. Reactive filter materials intended for filter systems and local sludge handling were investigated. The experimental methodology used to investigate reactive filter materials was also examined. The materials studied were blast furnace (BF) slag, wollastonite and clinoptilolite, which were investigated by agitation, column and pilot scale experiments as well as by literature studies. Ammonium and phosphate solutions and municipal wastewater were used in the experiments. The local sludge handling was investigated by a full-scale field study consisting of sludge freezing, drying and composting. Factors influencing phosphorus (P) sorption on BF slag in agitation experiments were grain size, weathering, initial P concentration and type of solution. The highest P sorption value obtained was 1,500 mg tot-P/kg slag for fresh BF slag treating a PO4-P solution of 20 mg tot-P/L. The results showed that the properties of BF slag had changed during storage, and the handling of BF slag before being used in a reactive filter system may affect the P treatment efficiency of full-scale filters. Considerable release of sulphuric compounds was seen in the pilot scale experiment even though the used slag was weathered. Thus, the use of fresh slag to optimise the P sorption may be a problem when considering sulphuric leakage. The P sorption of wollastonite was 90-93% for initial concentrations 14-61 mg PO4- P/L and the sorption was 190 mg PO4-P/kg wollastonite for a solution of 14 mg PO4-P/L. For the investigated wastewater, the PO4-P sorption of wollastonite was negligible. Wollastonite showed minor NH4+ removal, varying between 3 and 15%. Neither the reaction times nor the initial ammonium and phosphate concentrations influenced the ammonium sorption. In column experiments, where clinoptilolite was loaded with wastewater, the highest adsorption was obtained for the finest (4-8 mm) clinoptilolite, i.e. 2,700 mg NH4-N/kg. Breakthrough of ammonium occurred immediately in all clinoptilolite experiments. Laboratory experiments are easily performed with prepared solutions instead of wastewater. However, obtained sorption values from prepared solutions and wastewater differ, as shown in agitation experiments where the P sorption for fresh BF slag was almost 100% for an initial phosphate solution of 5 mg tot-P/L. The corresponding P sorption for a wastewater solution with an initial concentration of 4.2 mg tot-P/L was 56%. Filter experiments using wastewater are the laboratory experiment that can best forecast the performance of full-scale applications. A sorption capacity of the filter material can be obtained as well as information about other operation parameters, such as suitable grain size, hydraulic load and risk of clogging. Most small scale wastewater treatment systems include a sludge separation unit that separates a large fraction of the wastewater's suspended solids. The investigated full-scale septic sludge application was a promising method for septic sludge treatment in cold regions, due to its simple design and operation. Freezing and drying efficiently dewatered the sludge. The dried sludge and kitchen refuse were then intensively composted and a maximum temperature of 73 degrees C was achieved. Using the investigated sludge treatment method would contribute to the local recovery of wastewater nitrogen and phosphorus from small-scale wastewater treatment systems by approximately 5-20%.

  • 18.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Reactive filter systems for small scale wastewater treatment2006In: Vatten, ISSN 0042-2886, Vol. 62, no 3, p. 253-263Article in journal (Other academic)
  • 19.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Wollastonite as reactive filter medium for sorption of wastewater ammonium and phosphorus2006In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 27, no 7, p. 801-809Article in journal (Refereed)
    Abstract [en]

    The utilisation of reactive filter media to remove ammonium and phosphorus can improve the effluent water quality of wastewater treatment systems. The objective of this study was to estimate the ammonium and phosphorus sorption capacity of wollastonite, a calcium meta silicate (CaSiO3) that is distributed worldwide. Phosphorus sorption mechanisms were also investigated. Batch sorption experiments with agitating bottles were carried out and both phosphate and ammonium solutions as well as wastewater were used. The results showed minor ammonium adsorption, with only 3-15% of the ammonium in the solutions being adsorbed to the wollastonite. Neither the reaction time (0.5-20 h) nor the initial concentrations of phosphorus and ammonium (11-114 mg l(-1) NH4-N) were of importance. For high initial phosphate concentrations, phosphate was greatly adsorbed to the wollastonite (850 mg kg(-1) at an initial phosphate concentration of 61 mg l(-1) PO4-P). However, phosphate sorption was minor when the initial phosphate concentration was low. This study showed that sorption reactions were important when phosphate was removed by wollastonite, and indicated precipitation of phosphate on the wollastonite surfaces as one possible mechanism for phosphate retention. The results from this study indicated that the wollastonite investigated may not be suitable for municipal wastewater treatment applications due to the low phosphorus sorption capacity for low initial phosphorus concentrations.

  • 20.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Amofah, Lea Rastas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Adsorption and desorption of ammonium by clinoptilolite adsorbent in municipal wastewater treatment systems2008In: Journal of Environmental Engineering and Science, ISSN 1496-2551, E-ISSN 1496-256X, Vol. 7, no 1, p. 53-61Article in journal (Refereed)
    Abstract [en]

    Natural zeolites as clinoptilolite may be used to recover wastewater ammonium, decrease the nitrogen content in the effluent from on-site sanitation systems and in wastewater treatment plants when nitrification-denitrification efficiency is low. The objective of this study was to estimate the ammonium adsorption capacity of clinoptilolite when being loaded with wastewater. Phosphorus and potassium sorption, ammonium desorption with tap water, and clogging were also studied. The study was performed by column experiments. Results of the investigation showed the ammonium adsorption capacity to increase with decreasing grain size, and the highest experimental adsorption capacity was 2.7 mg NH4-N/g. The breakthrough occurred immediately, probably due to a too high loading rate. Phosphorus and potassium sorption were minor. Of adsorbed ammonium, 23% was desorbed by tap water and desorption was more pronounced during saturated conditions. Filter clogging was extensive and probably caused by particles in the effluent wastewater and by microbiological growth.

  • 21.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Amofah, Lea Rastas
    Methodological aspects of using blast furnace slag for wastewater phosphorus removal2006In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 132, no 11, p. 1431-1438Article in journal (Refereed)
    Abstract [en]

    Blast furnace (BF) slag is a by-product of steel plants. The objective of this study was to evaluate experimental methods to determine the phosphorus sorption capacity of BF slag. The handling of BF slag, before usage and clogging were also considered, as well as estimating the phosphorus retention capacity. Agitation and pilot-scale experiments were performed using both wastewater and phosphate solutions. This investigation showed that sorption capacities derived by wastewater experiments were considerably lower compared to those by phosphate solutions. Fresh BF slag briefly exposed to rainfall had a higher phosphorus sorption than weathered BF slag, indicating the importance of handling the slag carefully before usage. The risk for leakage of sulfuric compounds is considerable, especially during the initial operation phase of BF slag filters. Locations of BF slag filter beds for wastewater treatment must be carefully chosen from an environmental point of view.

  • 22.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Amofah, Lea Rastas
    Hanaeus, Jörgen
    Småskalig avloppsanläggning med salixbädd och sorbenter2007Report (Other academic)
    Abstract [en]

    In residential and rural areas in Sweden, a considerable number of houses are not connected to municipal wastewater treatment plants but the wastewater is treated in on-site sanitation systems. These systems contribute significantly to the anthropogenic discharge of phosphorus. Therefore, further development of small scale wastewater treatment systems is necessary. The aim of this project was to develop a small-scale wastewater treatment system to facilitate nutrient recovery. A full-scale experimental system with two treatment lines for a total flow of 1 m3/d was built. Investigated components of the system were a distribution layer, a willow bed with a root zone, followed by two parallel containers filled with filter materials for sorption of phosphorus. Filter material investigated in full-scale were Filtralite P and blast furnace (BF) slag. Besides the full-scale investigation, filter materials were investigated in laboratory. BF slag was investigated with respect to phosphorus sorption, wollastonite with respect to phosphorus and ammonium sorption and clinoptilolite with respect to ammonium adsorption.In the full-scale experiment suspended solids and organic matter was effectively reduced in the willow bed. The reduction of SS was 93% in average and the reduction of BOD was 86%. The effluent wastewater from the willow bed was sufficiently treated to avoid clogging of the following phosphorus filters. However, the nutrient reduction in the willow bed was moderate. The reduction of both total nitrogen and total phosphorus varied between 10 and 60%.The filter volume of Filtralite P and BF slag used in the full-scale investigation, 2,2 m3, was too small to achieve an efficient phosphorus reduction during one year. The investigated fresh slag sorbed more phosphorus compared to weathered slag. Thus, if the slag is covered during storage to prevent active substances to be leached out by precipitation, the phosphorus sorption of the slag will probably be preserved. BF slag contains sulphuric compounds. In both the laboratory and the full-scale studies, sulphuric compounds leached out when wastewater percolated through the filter. This can be a hinder for using BF slag in a wastewater treatment system.The investigated wollastonite and clinoptilolite can not be recommended to be used in small-scale wastewater treatment with respect to phosphorus and ammonium sorption. The investigated willow clones "Karin" and "Gudrun" could be establish as far north as in Luleå. The biomass production of the second growing season was as high as for salix clones with wastewater in southern Scandinavia.A willow bed combined with a phosphorus filter could be a robust small-scale wastewater treatment method but some components must be further developed.

  • 23.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Bergström, Agneta
    Norconsult AB, Stockholm.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    A Multi-criteria Analysis to Evaluate Stormwater Discharges in Relation to Receiving Water Status2014Conference paper (Refereed)
  • 24.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hanaeus, Jörgen
    Natural freezing, drying, and composting for treatment of septic sludge1999In: Journal of cold regions engineering, ISSN 0887-381X, E-ISSN 1943-5495, Vol. 13, no 4, p. 167-179Article in journal (Refereed)
    Abstract [en]

    A full-scale experimental plant intended for local treatment of septic sludge, situated in northern Sweden, is presented in this paper. The concept investigated included natural freezing, thawing, and drying in combination with composting. The experimental plant consisted of an undrained freezing-thawing-drying bed and a heat-insulated composter. About 500 L of fresh sludge, with a dry matter (DM) content of 4–5%, collected from a septic tank employed by one family, was transferred to the freezing-thawing-drying bed in the beginning of November 1996. During the winter months, the sludge froze and then thawed in the middle of May 1997. During a drying period of three weeks, the DM content increased from 10.6–21.3 to 25–95%. The final sludge volume and weight were 180 L and 54 kg, respectively. Approximate concentrations of nitrogen, phosphorus and total organic carbon of the dried sludge were determined to be 23, 5.9, and 346 g/kg DM. From June until the end of August, the sludge was cocomposted with kitchen refuse. Within two weeks, the composting temperature exceeded 65°C. The measured composting temperature indicated a high pathogen die-off, but before this concept can be suggested as an alternative to conventional septic sludge treatment, further studies should be conducted, including direct measurements of pathogens. The concept, however, has proved to be of interest in cold regions due to its simple construction and operation

  • 25.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Jönsson, Robert
    Vatten och Miljöbyrån.
    Mäki, Anna
    Vatten och Miljöbyrån.
    Tidiga förvarningssystem: är det någonting för våra kommuner?2009Report (Other academic)
    Abstract [en]

    The aim was to investigate different methods which can be used as earlywarning systems in drinking water supply. Technologies that are availabletoday is e.g. measurements of physical parameters, E. coli, odour benches,prediction models and biomonitors.

  • 26.
    Hedström, Annelie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Svensson, Gilbert
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water. SP Urban Water Management.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Challenges in water and wastewater transport systems in cold regions2016In: Water and wastewater management – challenges in cold climate / [ed] Harsha Ratnaweera, 2016Conference paper (Refereed)
    Abstract [en]

    The water and wastewater transport systems faces severe challenges due to climate change, resource constrain and an aging infrastructure. In cold regions the challenges are also related to general conditions societies have in common, e.g. sparsely populated, depopulation, long distances between populated areas and difficulties with recruiting right competence, beside the influence of the harsh climate on the technical system. In Sweden, municipal water services are financed by fees paid by the water utility users in a specific municipality. This means that water utilities in sparsely populated cold regions with on-going depopulation have limited economical resources to operate and maintain the transport and treatment systems for water and wastewater. The objectives of this paper are to illustrate the challenges for managing the transport system by comparing benchmark values for municipalities in cold regions with the Swedish averages, suggest possible measures to meet the challenges and give examples of on-going research in Stormwater&Sewers related to these questions.

  • 27.
    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

  • 28.
    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)
  • 29.
    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)
  • 30.
    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.

  • 31.
    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

  • 32.
    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.

  • 33.
    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)
  • 34.
    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.

  • 35.
    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.

  • 36.
    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.

  • 37.
    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.

  • 38.
    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.

  • 39.
    Herrmann, Inga
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Wilen, Britt-Marie
    Chalmers.
    Larsson, Charlotta
    Kungsbacka kommun.
    Forsberg, Bodil
    Kungsbacka kommun.
    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.
    Microorganisms in sand filters for on-site wastewater treatment2018Conference paper (Refereed)
  • 40.
    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.

  • 41.
    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.

  • 42.
    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)
  • 43.
    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.

  • 44.
    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)
  • 45.
    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)
  • 46.
    Mattsson, Jonathan
    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.
    Matavfallskvarnar: Långtidseffekter på ledningsnät2012Report (Other academic)
    Abstract [sv]

    Studien har undersökt långtidseffekter av matavfallskvarnar (MAK) på ledningsnät. MAK synes ha haft en påverkan, men denna var av mindre art. Ytterst sällan kunde någon större funktionsnedsättning påvisas.

  • 47.
    Mattsson, Jonathan
    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.
    The incompatibility of food waste disposers with an aging sewer: Fact or Fiction?2011Conference paper (Other academic)
    Abstract [en]

    Impacts of food waste disposers (FWD) on the general condition of sewer systems has recently received more attention as a large number of municipalities are contemplating large scale introductions of the device. The main reasons behind the elevated interest are an increase in biogas generation from the anaerobic digester as well as a lesser demand for vehicle transportation of solid waste. Concerns have however been raised regarding potential problems in the sewer network such as accumulations of biofilms, sediments and fats. This paper discusses long term impacts of said parameters on the sewer system for the two municipalities Surahammar and Smedjebacken who decided to introduce FWD on a larger scale more than a decade ago. The study targeted areas which mainly were comprised of detached houses with concrete pipes laid during the 70s and plastic pipes from the 80s. In total, 146 pipes of a cumulative length of about 7000 meters were filmed. By applying one grading system as well as one weighing system for all the encountered deposits, it was possible to calculate a final score for each pipe which reflects the relative abundance of deposits. All final points were then analyzed statistically with regard to FWD-load, material and inclination using general linear regression. The result from the inspections indicated that FWD has an impact, albeit a minor one. Ungrounded egg shells were encountered in many places, in particular where there were sags present. The level of total amount of sediments was however not documented to be generally elevated when compared to pipes with few to none FWD. Biofilms and fats seemed to be slightly increased when in particular the ratio of households having installed a FWD upstream was high as well as for pipes which were installed with a gentle slope. As kitchen waste that was never intended for the FWD in the first place has been documented in the sewer, there also seems to be a further demand for informational campaigns regarding the operation of the device.

  • 48.
    Mattsson, Jonathan
    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.
    Ashley, Richard
    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.
    Impacts and managerial implications for sewer systems due to recent changes to inputs in domestic wastewater: a review2015In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 161, p. 188-197Article in journal (Refereed)
    Abstract [en]

    Ever since the advent of major sewer construction in the 1850s, the issue of increased solids deposition in sewers due to changes in domestic wastewater inputs has been frequently debated. Three recent changes considered here are the introduction of kitchen sink food waste disposers (FWDs); rising levels of inputs of fat, oil and grease (FOG); and the installation of low-flush toilets (LFTs). In this review these changes have been examined with regard to potential solids depositional impacts on sewer systems and the managerial implications. The review indicates that each of the changes has the potential to cause an increase in solids deposition in sewers and this is likely to be more pronounced for the upstream reaches of networks that serve fewer households than the downstream parts and for specific sewer features such as sags. The review has highlighted the importance of educational campaigns directed to the public to mitigate deposition as many of the observed problems have been linked to domestic behaviour in regard to FOGs, FWDs and toilet flushing. A standardized monitoring procedure of repeat sewer blockage locations can also be a means to identify depositional hot-spots. Interactions between the various changes in inputs in the studies reviewed here indicated an increased potential for blockage formation, but this would need to be further substantiated. As the precise nature of these changes in inputs have been found to be variable, depending on lifestyles and type of installation, the additional problems that may arise pose particular challenges to sewer operators and managers because of the difficulty in generalizing the nature of the changes, particularly where retrofitting projects in households are being considered. The three types of changes to inputs reviewed here highlight the need to consider whether or not more or less solid waste from households should be diverted into sewers.

  • 49.
    Mattsson, Jonathan
    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.
    Bridging the gap between sewer status and new sewer inputs: A decision support tool to predict the effect of food waste disposers’ effluent on small-diameter sewers2013Conference paper (Refereed)
  • 50.
    Mattsson, Jonathan
    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.
    Indicators for blockages caused by changing wastewater – How well does a municipality need to know its sewer?2014Conference paper (Refereed)
12 1 - 50 of 82
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