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  • 51.
    Odlare, Monica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Microbiological degradation of explosives in bioreactor2007Conference paper (Refereed)
  • 52.
    Odlare, Monica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Microbiological degradation of explosives in bioreactor2006Conference paper (Refereed)
  • 53.
    Odlare, Monica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Ribé, Veronica
    Mälardalen University, School of Business, Society and Engineering.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Grube, Mara
    Latvia University.
    Gavare, Marita
    Latvia University.
    Cultivation of algae with indigenous species – potentials for regional biodiesel, biogas and biofuel production.2010Conference paper (Refereed)
  • 54.
    Odlare, Monica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering.
    Ribé, Veronica
    Mälardalen University, School of Business, Society and Engineering.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Grube, Mara
    University of Latvia.
    Gavare, Marita
    University of Latvia.
    Cultivation of algae with indigenous species: potentials for regional biofuel production2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 10, p. 3280-3285Article in journal (Refereed)
    Abstract [en]

    The massive need for sustainable energy has led to an increased interest in new energy resources, such as production of algae, for use as biofuel. There are advantages to using algae, for example, land use is much less than in terrestrial biofuel production, and several algae species can double their mass in one day under optimized conditions. Most algae are phototrophs and some are nitrogen fixing. Algae production therefore requires only small amounts of amendments such as carbon sources and nutrients. In the present paper an experiment was performed using water sampled from Lake Mälaren in Sweden. The lake water is considered nutrient rich, has relatively neutral pH and is rich in organic compounds and suspended solids. The idea behind this research was to enhance indigenous algae production rather than inoculate new species into the system. A simple experimental setup was designed where algae biomass growth was measured regularly over a 13 day period. FT-IR absorption spectra were evaluated in order to determine protein, lipid, carbohydrate and silicate contents of the algae. The algae community structure was characterized throughout the production cycle. Futhermore, the potential for energy supply for the transportation sector in the Mälardalen region from algae cultivated as tested in the experiment was evaluated.

  • 55.
    Odlare, Monica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Rodriguez, Adrian
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Microbiological degradation of explosives in bioreactor – experiences from Nammo Vingåkersverken.2008Conference paper (Refereed)
  • 56.
    Odlare, Monica
    et al.
    Mälardalen University, School of Business, Society and Engineering. Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Pell, Mikael
    SLU.
    Arthurson, Veronica
    SLU.
    Abubaker, Jamal
    SLU.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering. Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Combined mineral N and organic waste fertilization effects oncrop growth and soil properties2014In: The Journal of Agricultural Sciences, ISSN 0021-8596, Vol. 152, no 01, p. 134-145Article in journal (Refereed)
    Abstract [en]

    An 8-year-long field experiment (1998–2006) was established in Sweden with the aim of evaluating the effects of applying organic wastes in combination with mineral nitrogen (N) to agricultural soil. Sewage sludge (SS), biogas residues (BR) and municipal compost (CO) were applied annually at rates corresponding to 50 kg N/ha and supplementary mineral N fertilizer lso applied at rates corresponding to 50 kg N/ha. The effects were evaluated by analysing crop yield and soil chemical and microbiological properties. The results showed that none of the fertilizers produced significantly higher yield of barley over the 8-year period compared to any other. Biogas residue proved to be particularly beneficial for the substrate-induced respiration (SIR) in soil and increased the proportion of active to dormant micro-organisms. Treatment with SS increased plant-available phosphorus (P-AL) and N mineralization (N-min), whereas CO increased the basal respiration (B-resp). Changes in the microbial community structure were assayed by terminal restriction fragment length polymorphism (T-RFLP); the T-RFLP signatures of the soil bacterial community were largely unaffected by the addition of organic waste. Of the chemical properties assayed, the largest increases were seen in P-AL, where SS produced the highest value. Treatmentswith the organicwastes showed no negative effects other than a slight decrease in B-resp induced by SS and BR. In conclusion, the microbiological activity in the soil responded more rapidly than the changes in the community structure and the chemical properties to changes in the soil environment.

  • 57.
    Olga, Chusova
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Adsorption of trinitrotoluene (TNT) by pine bark2015Manuscript (preprint) (Other academic)
  • 58.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Feng, Xin Mei
    JTI, Swedish Inst Agr & Environm Engn, SE-75007 Uppsala, Sweden .
    Ascue, Johnny
    JTI, Swedish Inst Agr & Environm Engn, SE-75007 Uppsala, Sweden .
    Gentili, Francesco G.
    Swedish Univ Agr Sci, Dept Wildlife Fish & Environm Studies, SE-90183 Umea, Sweden .
    Shabiimam, M. A.
    Indian Inst Technol, Ctr Environm Sci & Engn, Bombay 400076, Maharashtra, India.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatment2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 171, p. 203-210Article in journal (Refereed)
    Abstract [en]

    In this study two wet microalgae cultures and one dried microalgae culture were co-digested in different proportions with sewage sludge in mesophilic and thermophilic conditions. The aim was to evaluate if the co-digestion could lead to an increased efficiency of methane production compared to digestion of sewage sludge alone. The results showed that co-digestion with both wet and dried microalgae, in certain proportions, increased the biochemical methane potential (BMP) compared with digestion of sewage sludge alone in mesophilic conditions. The BMP was significantly higher than the calculated BMP in many of the mixtures. This synergetic effect was statistically significant in a mixture containing 63% (w/w VS based) undigested sewage sludge and 37% (w/w VS based) wet algae slurry, which produced 23% more methane than observed with undigested sewage sludge alone. The trend was that thermophilic co-digestion of microalgae and undigested sewage sludge did not give the same synergy.

  • 59.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Forkman, T.
    Swedish University of Agricultural Sciences, Sweden.
    Gentili, F.G.
    Swedish University of Agricultural Sciences, Sweden.
    Zambrano, Jesús
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Anaerobic co-digestion of sludge and microalgae grown inmunicipal wastewater: A feasibility study2018In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 77, no 3, p. 682-694Article in journal (Refereed)
    Abstract [en]

    In this study a natural mix of microalgae grown in wastewater of municipal character was co-digested with sewage sludge in mesophilic conditions, in both batch and semi-continuous modes. The semicontinuous experiment was divided into two periods with OLR 1 (Organic Loading Rate) of 2.4 kg VS m3 d-1 and HRT1 (Hydraulic Retention Time) of 15 days, and OLR2 of 3.5 kg VS m3 d-1 and HRT2 of 10 days respectively. Results showed stable conditions during both periods. The methane yield was reduced when adding microalgae (from 200 ± 25 NmL CH4 g VSin-1 , to 168±22 NmL CH4 g VSin-1). VS reduction was also decreased by 51%. This low digestability was confirmed in the anaerobic batch test. However, adding microalgae improved the dewaterability of the digested sludge. The high heavy metals content in the microalgae resulted in a high heavy metals content in the digestate, making it more difficult to reuse the digestate as fertilizer on arable land. The heavy metals are thought to originate from the flue gas used as a CO2 source during the microalgae cultivation. Therefore the implementation of CO2 mitigation via algal cultivation requires careful consideration regarding thesource of the CO2-rich gas.

  • 60.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Ma, Shabiimam
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatmentManuscript (preprint) (Other academic)
    Abstract [en]

    One way to meet the increased demand for biogas in the society is to use microalgae as substrate. These algae would be cultivated in a treatment step of photobioreactors for reject water from sludge dewatering facilities. In the present study, a co-digestion experiment was established where sludge from a municipal wastewater treatment plant was fermented with harvested microalgae cultivated in lake water from lake Mälaren. The experiment was carried out as a BMP-test (Biochemical Methane Potential) under mesophilic condition (37°C) with fermentation bottles, where 0, 12, 25 and 37%, of the sludge was replaced with harvested microalgae. The results showed that the biogas production was improved with 12% for the bottles with 12% microalgae compared with the bottles with only sludge as a substrate. In the bottles with 25% and 37% microalgaes the gas production was slightly reduced compared with the bottles where only sludge was used.

  • 61.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Philipson, M.
    Uppsala University, Sweden.
    Holmström, H.
    Uppsala Vatten Och Avfall AB, Sweden.
    Cato, E.
    Uppsala Vatten och Avfall AB, Sweden.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Energy efficient combination of sewage sludge treatment and hygenization after mesophilic digestion - Pilot study2014In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, p. 587-590Article in journal (Refereed)
    Abstract [en]

    Biogas production is probably the most feasible way of utilizing sewage sludge as energy source, simultaneously with nutrient recovery by recycling the biogas digestate (i.e. The residue) to arable land. However, the sludge commonly contains high amounts of human pathogenic bacteria excreted in faeces and urine. To use sludge as fertilizer on food producing land is therefore a controversial issue, partly because of the risk of spreading diseasecausing pathogens. The Swedish environment protection agency (SEPA) pre-approved two hygenization methods for the treatment of the sludge due to their positive effects on the sludge quality. One of them, conventional pasteurization (70 °C, 1 h), was investigated for its feasibility in Uppsala, Sweden, and it was found that the heat consumption was very high. The other method has the advantage of potentially increase the produced biogas. This hygenization method has been investigated in the present study through a pilot experiment where thickened mesophilic digested sludge is digested once more at thermophilic conditions (55 °C). The aim of the study was to investigate the possibility to develop this self-sufficient (in heat and electricity) hygenization method. The results showed an increase in the gas production from 430 dm3/kg VSin to 610 dm3/kg VSin by adding the thermophilic step. This increase gave an energy balance with an excess of both heat and electricity. Sludge hygenization was sufficient with the method and another important result is the significant decrease digestate volume.

  • 62.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Co-digestion of microalgae, grown on municipal wastewater, and primary sewage sludge–: Pilot study in thermophilic and mesophilic conditions2017Conference paper (Refereed)
    Abstract [en]

    The most common biological treatment in a municipal waste water today is the activated sludge process (ASP). A possible substitution of the ASP could be the utilization of microalgae for the reduction and/or transformation of nutrients. The produced algal biomass can be converted to biofuel by anaerobic digestion. In the present study, co-digestion of primary sludge and microalgae are studied in semi-continuous tests at mesophilic and thermophilic conditions. Two reactors fed by waste activated sludge and primary sludge are used as reference. The results show that thermophilic digestion of microalgae and primary sludge is less attractive since the methane yield is approximately the same as the mesophilic digestion. In mesophilic conditions the results are approximately the same in the two pilot reactors and also comparable with the mesophilic full-scale digesters in Västerås, Sweden.

  • 63.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Mesophilic and thermophilic co-digestion of microalgal-based activated sludge and primary sludgeIn: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732Article in journal (Refereed)
  • 64.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Microalgae as biological treatment for municipal wastewater - Effects on the sludge handling in a treatment plant2018In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, ISSN 0273-1223, Vol. 78, no 3, p. 644-654Article in journal (Refereed)
    Abstract [en]

    A mix of microalgae and bacteria was cultivated on pre-sedimented municipal wastewater in a continuous operated microalgae-activated sludge process. The excess material from the process was co-digested with primary sludge in mesophilic and thermophilic conditions in semi-continuous mode (5 L digesters). Two reference digesters (5 L digesters) fed with waste-activated sludge (WAS) and primary sludge were operated in parallel. The methane yield was slightly reduced (≈10%) when the microalgal-bacterial substrate was used in place of the WAS in thermophilic conditions, but remained approximately similar in mesophilic conditions. The uptake of heavy metals was higher with the microalgal-bacterial substrate in comparison to the WAS, which resulted in higher levels of heavy metals in the digestates. The addition of microalgal-bacterial substrate enhanced the dewaterability in thermophilic conditions. Finally, excess heat can be recovered in both mesophilic and thermophilic conditions. 

  • 65.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Shabiimam, MA
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    CO-DIGESTION OF CULTIVATED MICROALGAE AND SEWAGE SLUDGE FROM MUNICIPAL WASTE WATER TREATMENT2013Conference paper (Refereed)
    Abstract [en]

    The demand for biogas is continuously growing and the biogas substrate, such as food waste, may soon become limited and it is therefore important for biogas producers to expand the range of substrates. One way can be to use microalgae in co-digestion with sewage sludge.

    The present study explores the possibilities to use harvested microalgae from Lake Mälaren, as a co-substrate to sewage sludge in biogas production under mesophilic and thermophilic conditions. The aim is to investigate if co- digestion of microalgae and sewage sludge is more efficient for biogas production compared using the sludge alone. The study has been carried out as a BMP-experiment (Biochemical Methane Potential) in batch fermentation bottles. The substrate was undigested sludge where 0%, 12 %, 25 % and 37 % were replaced with the cultivated microalgae. The results showed that the use of an algae/bacteria community, cultivated in prior to digestion, can serve as a biomass substrate for biogas production together with municipal wastewater sludge. Co-digestion of microalgae and sewage sludge can be more efficient for biogas production compared to using the sludge alone under mesophilic conditions. It can also be concluded that thermophilic co-digestion between the microalgae and sludge give lower biochemical methane potential. 

  • 66.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    TRANSITION OF MESOPHILIC TO THERMOPHILIC DIGESTION OF SEWAGE SLUDGE2016In: TRANSITION OF MESOPHILIC TO THERMOPHILIC DIGESTION OF SEWAGE SLUDGE, 2016Conference paper (Refereed)
    Abstract [en]

    In this comparative study two types of temperature transition strategies from mesophilic to thermophilic conditions in anaerobic digestion was explored. Both strategies used a rapid increase from 37 to 55°C with a constant organic loading rate (2.4 kg VS m-3 d-1) and hydraulic retention time (14 d). The two digesters used the same mesophilic inoculoum but in the second digester a small share of thermophilic digeastate was also inoculated. A comparative dewaterability study between the fullscale mesophilic digestate and the thermophilic digestates were also performed as part of the study. The results showed a stabilization in both digesters within 14 days (1 Hydraulic retention time). The digester where a small share of thermophilic inoculum was introduced had a higher methane production compared to the control reactor where just mesophilic inoculum was used. The comparative dewaterability study showed a deterioration of the dewaterability in both digesters when thermophilic conditions was established.

  • 67.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Juszkiewicz, Agnieszka
    Mälarenergi AB, Sweden.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    COMPARATIVE STUDY – PHARMACEUTICAL RESIDUES IN WASTEWATER AND SLUDGE FROM A MICORALGAE PLANT AND AN ACTIVATED SLUDGE PROCESS2016Conference paper (Refereed)
    Abstract [en]

    This study explores the possibility of using a microalgae based activated sludge – process (MAAS-process) to increase the reduction of pharmaceutical residues in outgoing wastewater, compared to a conventional wastewater treatment plant with activated sludge process. In an on-site study, residual sludge from four pilot scale digesters fed with primary sludge and waste activated sludge or microalgae were sampled and analysed for pharmaceutical residues. The aim of the study was to compare the reduction efficiencies of a microalgae based process with a conventional biological treatment and also to explore the reduction of the residues in the different process steps including the sewage sludge thickening before the anaerobic digestion, the digestion and the secondary treatment with the sludge dewatering process. The results show that the total reduction of pharmaceutical residues in the water phase appears to be significantly higher in the MAAS-process. The substance diclofenac was not degraded in any of the biological processes in the study. The reduction of pharmaceutical residues in digested sludge seems to be higher in mesophilic conditions compared with thermophilic conditions.

  • 68.
    Olsson, Jesper
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Tova, Forkman
    Uppsala Universitet, Sweden.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    CONTINUOUS CO-DIGESTION OF MICROALGAE AND REPRESENTATIVE MIX OF SEWAGE SLUDGE: -2014Conference paper (Refereed)
    Abstract [en]

    A natural mix of microalgae grown on wastewater was co-digested with a representative mix of sewage sludge in a semicontinuous pilot digester system. The share of microalgae in the mix were 37 % calculated as VS-content. The organic loading rate was 2.4 kg VS (volatile solids) m-3d-1 and the hydraulic retention time was 15 d in a reference reactor, with just a representative mix of sewage sludge, and a digester where microalgae were added. The results from the three retention times showed that the addition of the microalgae enhanced the methane yield with 39 % for every gram reduced VS in the reactors. The specific methane yield for every gram added VS to the reactors were 9 % lower in the digester where microalgae had been added. Less sludge was degraded when microalgae were added, but more methane was produced for every gram VS reduced. CST-measurements indicated that the addition of microalgae enhance the dewaterability of the digested sludge.

  • 69.
    Pierong, Rasmus
    et al.
    Uppsala University.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Carlsson, Bengt
    Uppsala University.
    Zambrano, Jesús
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Algae Based Wastewater Treatment Model Using The RWQM12016Conference paper (Refereed)
    Abstract [en]

    In this paper, we propose a model describing the dynamics of an algae based wastewater treatment process in an activated sludge environment. As the basis for the process modelling, the River Water Quality Model no. 1 (RWQM1) is chosen. In order to evaluate the applicability of the model to an activated sludge process, the proposed model is compared to the Activated Sludge Model no. 1 (ASM1).

  • 70.
    Ribe, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Assessment of mobility and bioavailability of contaminants in MSW incineration ash with aquatic and terrestrial bioassays2014In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 34, no 10, p. 1871-1876Article in journal (Refereed)
    Abstract [en]

    Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction as well as a source of renewable energy. In the process fly and bottom ash is generated as a waste material. The ash residue may vary greatly in composition depending on the type of waste incinerated and it can contain elevated levels of harmful contaminants such as heavy metals. In this study, the ecotoxicity of a weathered, untreated incineration bottom ash was characterized as defined by the H14 criterion of the EU Waste Framework Directive by means of an elemental analysis, leaching tests followed by a chemical analysis and a combination of aquatic and solid-phase bioassays. The experiments were conducted to assess the mobility and bioavailability of ash contaminants. A combination of aquatic and terrestrial bioassays was used to determine potentially adverse acute effects of exposure to the solid ash and aqueous ash leachates. The results from the study showed that the bottom ash from a municipal waste incineration plant in mid-Sweden contained levels of metals such as Cu, Pb and Zn, which exceeded the Swedish EPA limit values for inert wastes. The chemical analysis of the ash leachates showed high concentrations of particularly Cr. The leachate concentration of Cr exceeded the limit value for L/S 10 leaching for inert wastes. Filtration of leachates prior to analysis may have underestimated the leachability of complex-forming metals such as Cu and Pb. The germination test of solid ash and ash leachates using T. repens showed a higher inhibition of seedling emergence of seeds exposed to the solid ash than the seeds exposed to ash leachates. This indicated a relatively low mobility of toxicants from the solid ash into the leachates, although some metals exceeded the L/S 10 leaching limit values for inert wastes. The Microtox (R) toxicity test showed only a very low toxic response to the ash leachate exposure, while the D. magna immobility test showed a moderately high toxic effect of the ash leachates. Overall, the results from this study showed an ecotoxic effect of the solid MSW bottom ash and the corresponding ash leachates. The material may therefore pose an environmental risk if used in construction applications. However, as the testing of the solid ash was rather limited and the ash leachate showed an unusually high leaching of Cr, further assessments are required in order to conclusively characterize the bottom ash studied herein as hazardous according to the H14 criterion.

  • 71.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Aulenius, Elisabet
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Martell, Ulrika
    Structor Environmental Engineering.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Applying the Triad method in a risk assessment of a former surface treatment and metal industry site2012In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 207, no SI, p. 15-20Article in journal (Refereed)
    Abstract [en]

    With a greater focus on soil protection in the EU, the need for ecological risk assessment tools for cost-effective characterization of site contamination is increasing. One of the challenges in assessing the risk of soil contaminants is to accurately account for changes in mobility of contaminants over time, as a result of ageing. Improved tools for measuring the bioavailable and mobile fraction of contaminants is therefore highly desirable. In this study the Triad method was used to perform a risk characterization of a former surface treatment and metal industry in Eskilstuna, Sweden. The risk assessment confirmed the environmental risk of the most heavily contaminated sample and showed that the toxic effect was most likely caused by high metal concentrations. The assessment of the two soil samples with low to moderate metal contamination levels was more complex, as there was a higher deviation between the results from the three lines of evidence; chemistry, (eco)toxicology and ecology. For the slightly less contaminated sample of the two, a weighting of the results from the ecotoxicological LoE would be recommended in order to accurately determine the risk of the metal contamination at the sampling site as the toxic effect detected in the Microtox® test and Ostracodtoxkit™ test was more likely to be due to oil contamination. The soil sample with higher total metal concentrations requires further ecotoxicological testing, as the integrated risk value indicated an environmental risk from metal contamination. The applied methodology, the Triad method, is considered appropriate for conducting improved environmental risk assessments in order to achieve sustainable remediation processes.

  • 72.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Fredriksson, Karin
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ljunggren, Isabell
    VAFAB Miljö, Sverige.
    Stenberg, Sara
    VAFAB MILJÖ, Sverige.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Assessment of the final cover system of a closed landfill in Sweden2014Conference paper (Refereed)
  • 73.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Aulenius, Elisabet
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Martell, Ulrika
    Structor Miljöteknik.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    RISK CHARACTERISATION OF A FORMER SURFACE TREATMENT AND METAL INDUSTRY SITE USING THE TRIAD METHOD2010In: Crete 2010, 2nd International Conference, Hazardous and Industrial Waste Management, Proceedings / [ed] E. Gidarakos; R. Cossu; R. Stegmann, 2010, p. 451-452Conference paper (Refereed)
    Abstract [en]

    With a greater focus on soil protection in the EU, in combination with the ever-growing pressures of redevelopment of contaminated and former brownfield sites, the need for ecological risk assessment tools for cost-effective characterization of site contamination is increasing. One of the greatest challenges in assessing the actual risk of soil contaminants is to accurately account for the reduced or increased mobility of contaminants over time, as a result of bioavailability. Improved tools for measuring the bioavailable and mobile fraction of the contaminants, as opposed to total concentrations, is therefore highly desirable. In this study the triad method was used to perform a risk characterization of a former surface treatment and metal industry, now used for the student union buildings of the Mälardalen University in Eskilstuna, Sweden. The risk assessment with the TRIAD method confirmed the environmental risk of sample D and showed that the toxicity of the sample was most likely caused by the high metal concentrations in the soil. The risk assessment of sample B and C was more complex, as there was a higher deviation between the results from the chemical analyses, ecotoxicological bioassays and the ecological inventory for these two samples. Further ecotoxicological bioassays are therefore suggested, in order to accurately determine the risk and potential remediation requirements of these soils.

  • 74.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Carlsson, Peter
    Structor Environmnetal Technology, Eskilstuna, Sweden.
    Eneroth, Peder
    Flexiclean, Growhouse, Kista, Sweden.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    COMPARATIVE STUDY OF FIVE FILTER TYPES FOR STORMWATER TREATMENT: USING A WHOLE EFFLUENT ASSESSMENT APPROACH TO EVALUATE FILTER PERFORMANCEManuscript (preprint) (Other academic)
    Abstract [en]

    The release of hazardous substances to the environment from industrial activities in Sweden is heavily restricted due to pieces of legislation such as the Industrial Emissions Directive (2010/75/EU). In the directive, the whole effluent assessment (WEA) methodology is included as a suitable approach to characterization of effluent waters. The use of WEA methods in the evaluation of treatments for complex effluent waters has great advantages when comparing to using chemical analysis of individual substances alone. In this comparative study the WEA methodology of combining toxicity testing with chemical analysis was applied to evaluate the performance, stability and safety of four stormwater filter types in comparison with the conventional filter material active carbon. The filter materials were the two sorbent filter materials pine bark and polonite; and the two combination filters pine bark/polonite (filtration through pine bark followed by filtration through polonite) and polonite/pine bark (filtration through polonite followed by filtration through pine bark). The stormwater treated in the study was sampled from two points at a metals manufacturing site in mid-Sweden. A preliminary analysis of the water showed high concentrations of heavy metals and in particular of Zn, with concentrations exceeding 36 mg/L. The stormwater pH was neutral (7.5) and suspended solids content was approximately 130 mg/l. Samples of the stormwater, corresponding to ten filter bed volumes, were filtered through a pilot-scale 250 ml filter columns with the four filters or activated carbon. The filtered water samples were analysed for Zn and pH. An aquatic ecotoxicity test battery was used to measure acute and chronic toxic effects of the untreated and treated stormwater samples. The test battery assessed luminescent bacteria acute toxicity (30-min Microtox® ISO 11348-3 using Vibrio fischeri), growth inhibition of the green unicellular algae Pseudokirchneriella subcapitata and genotoxicity with the bacterial umu assay using Salmonella typhimurium TA1535/pSK1002 (ISO 13829). The pine bark sorbent showed the highest average Zn removal efficiency of the single filter materials after activated carbon. The results from the stormwater filtration with combination materials were difficult to interpret. All filter types, except pine bark, increased pH of the treated waters > 9. Pine bark lowered the pH of the treated water below 5 even after filtration of 10 bed volumes of stormwater. Although pH of the treated waters was only adjusted for the Microtox test, there was a statistically significant positive correlation between the response of this test and the algal assay. Activated carbon showed the highest reduction of Zn contamination and toxicity of the treated waters. There was no significant correlation between the level of zinc contamination and toxic response of the treated waters. Although pine bark lowered pH significantly, in comparison to the other filter types, there was no significant correlation between the pH and the toxic response of the filtered waters.

  • 75.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Using an ecotoxicological bioassay battery for assessing the performanc eand safety of a pine bark filter material for landfill leachate treatment2009In: SETAC Europe 19th Annual Meeting Abstract Book, Göteborg 31 May - 4 June, 2009, 2009, p. 144-Conference paper (Refereed)
    Abstract [en]

    The use of ecotoxicological bioassays in hazardous waste management and the water treatment industry is growing in order to meet increasingly stringent legislative requirements. Ecotoxicological tests are particularly useful for assessing the safety of samples with a complex contaminant matrix, as interactive effects between contaminants, which may affect sample toxicity, can go undetected if chemical analyses alone are used in the assessment process. By combining a wide range of tests it is possible to assess non-specific acute and chronic effects, as well as specific toxic effects such as genotoxicity, in vertebrates and invertebrates and in aquatic and terrestrial organisms over several trophic levels. Ecotoxicological tests are less commonly used during method and process development, where they may be used as a rapid and cost-effective way to evaluate performance and safety. This paper describes current and future work with a battery of ecotoxicological bioassays evaluating the use of a pine bark sorbent for treating landfill leachate and polluted process water. The results presented in the paper are from the first phase of the ecotoxicological evaluation of the filter, where the leaching properties of the filter material itself were investigated. Batch leaching tests were performed to determine the release of several metals, dissolved organic carbon (DOC) and phenol. Toxicity of the leachate to Daphnia magna was measured in acute toxicity tests, with and without pH adjustment of the leachate. To determine the duration and extent of the initial desorption of organic material from the pine bark filter serial batch leaching experiments were carried out. The change in toxicity of the leachates to Daphnia magna was assessed in acute toxicity tests.

  • 76.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Berglind, Rune
    FOI CBRN Defence and Security, Swedish Defence Research Agency.
    Forsberg, Åke
    Mälardalen University, School of Sustainable Development of Society and Technology.
    EVALUATION OF THE PERFORMANCE AND SAFETY OF A PINE BARK FILTER FOR LANDFILL LEACHATE AND STORMWATER TREATMENT: TOXICITY TESTING AND CHEMICAL ANALYSIS2011In: Sardinia 2011 Symposium, Thirteenth International Waste Management and Landfill Symposium, Proceedings / [ed] R. Cossu, CISA Publisher , 2011, p. 1143-Conference paper (Refereed)
    Abstract [en]

    The industrial by-product pine bark has been used successfully as a low-cost sorbent for removing heavy metals from wastewaters such as stormwaters and landfill leachates. Although the water treatment efficiency of pine bark is high, one reported drawback with using the filter material for water treatment is the potential leaching of organic compounds, e.g. tannines and other polyphenols. This phenomenon is likely to be particularly pronounced during the initial start-up phase of filtration with unused pine bark. The results from preliminary serial leaching tests with the filter material, has shown that the toxicity of the pine bark leachates to Daphnia magna (48 hr) decreases after each successive round of leaching. The aim of this study was to further investigate the leaching properties and stability of pine bark filter. In this study, parallel serial batch leaching experiments were performed with either doubly deionised or U.S. EPA moderately hard reconstituted water as leachant to determine the duration and extent of the initial desorption of organic material, analysed as DOC (Dissolved Organic Carbon), from the filter material. To further investigate the changes in toxicity of the pine bark leachates from each successive round of leaching, a more extensive toxicity assessment was performed with an aquatic ecotoxicity test battery consisting of an acute luminescent bacteria test (ROTAS) and a genotoxicity test (the Umu assay using Salmonella typhimurium TA1535/pSK1002). 

  • 77.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Gustavsson, Lillemor
    Karlskoga Energi & Miljö AB.
    Berglind, Rune
    FOI CBRN Defence and Security, Swedish Defence Research Agency.
    Forsberg, Åke
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Ecotoxicological assessment and evaluation of a pine bark biosorbent treatment of five landfillleachates2012In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 32, no 10, p. 1886-1894Article in journal (Refereed)
    Abstract [en]

    When selecting a landfill leachate treatment method the contaminant composition of theleachate should be considered in order to obtain the most cost-effective treatment option. In this studythe filter material pine bark was evaluated as a treatment for five landfill leachates originating fromdifferent cells of the same landfill in Sweden. The objective of the study was to determine the uptake,or release, of metals and dissolved organic carbon (DOC) during a leaching test using the pine barkfilter material with the five different landfill leachates. Furthermore the change of toxicity aftertreatment was studied using a battery of aquatic bioassays assessing luminescent bacteria (Vibriofischeri) acute toxicity (30-min Microtox®), immobility of the crustacean Daphnia magna, growthinhibition of the algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor; andgenotoxicity with the bacterial Umu-C assay. The results from the toxicity tests and the chemicalanalysis were analyzed in a Principal Component Analysis and the toxicity of the samples before andafter treatment was evaluated in a toxicity classification. The pine bark filter material reduced theconcentrations of metal contaminants from the landfill leachates in the study, with some exceptions forCu and Cd. The Zn uptake of the filter was high for heavily contaminated leachates (≥73%), althoughsome desorption of zinc occurred in less contaminated waters. Some of the leachates may requirefurther treatment due to discharge into a natural recipient in order to reduce the risk of possiblebiological effects. The difference in pH changes between the different leachates was probably due tovariations in buffering capacity, affected by physicochemical properties of the leachate. The greatestdesorption of phenol during filtration occurred in leachates with high conductivity or elevated levels ofmetals or salts. Generally, the toxicity classification of the leachates implies that although filtertreatment with pine bark removes metal contaminants from the leachates effectively, it does not alterleachate toxicity noticeably. The leachates with the highest conductivity, pH and metal concentrationsare most strongly correlated with an increased toxic response in the score plots of both untreated andtreated leachates. This is in line with the toxicity classification of the leachate samples. The results fromthis study highlight the importance of evaluating treatment efficiency from the perspective of potentialrecipient effects, rather than in terms of residual concentrations of individual contaminants whentreating waters with a complex contamination matrix, such as landfill leachates.

  • 78.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Waara, Sylvia
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Leaching of contaminants from untreated pine bark in a batch study: Chemical analysis and ecotoxicological evaluation2009In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 163, no 2-3, p. 1096-1100Article in journal (Refereed)
    Abstract [en]

    Low cost sorbents have been widely studied in recent years in the search for filter materials that retain contaminants from water. One promising, low cost material is pine bark, a by-product from the forest industry. Many studies have shown that pine bark has great potential for the treatment of metals and organic substances, as a replacement for other commercial sorbents such as active carbon. However, some potential problems are introduced through the use of natural materials and by-products. One such problem that must be addressed is the possibility of leaching of contaminants from the filter material, especially in the initial filtration step or during flushes of lightly contaminated water, e.g. during rainfall for on-site treatment of stormwater or landfill leachate. The aim of this preliminary studywas therefore to identify potential risks and limitations of using pine bark as a filter material. Leachate from a standardized batch test was analysed for metals, dissolved organic carbon (DOC) and phenols. In addition to these chemical analyses, an ecotoxicological test was conducted using the test organism

    Daphnia magna. The results showed significant leaching of DOC and some metals. Only a small fraction of the DOC was present as phenols. The leachate was however found to be toxic to the test organism without pH adjustment, and the EC 50 was established at an approximate leachate concentration of 40%. This was concluded to be related to the low pH in the eluate, since no toxicity was observed after pH adjustment before the toxicity tests.

  • 79.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Waara, Sylvia
    Högskolan i Halmstad.
    Forsberg, Åke
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Allard, Bert
    Örebro universitet.
    Assessment of the safety and performance of a low-cost filter material for treatment of landfill leachate and industrial wastewater using an integrated approach based on ecotoxicological testing and chemical analysis2009In: 12th EuCheMS International Conference on Chemistry and the Environment, 2009Conference paper (Refereed)
  • 80.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Waara, Sylvia
    Högskolan i Halmstad.
    Gustavsson, Lillemor
    Karlskoga Energi & Miljö AB.
    Forsberg, Åke
    Mälardalen University, School of Sustainable Development of Society and Technology.
    USING ECOTOXICOLOGICAL TESTS IN THE DEVELOPMENT OF A LOW-COST FILTERING SYSTEM FOR LANDFILL LEACHATE2009In: Sardinia 2009 Symposium, Twelth International Waste Management and Landfill Symposium, Proceedings / [ed] R. Cossu; L.F. Diaz; R. Stegmann, CISA Publisher , 2009, p. 435-436Conference paper (Refereed)
    Abstract [en]

    This paper describes the use of aquatic ecotoxicological tests, in combination with chemical analysis, in the evaluation of the application of low-cost pine bark sorbent, a by-product of the forestry industry, to treat low-strength landfill leachate. Initially, leaching batch tests with the untreated filter material were carried out to investigate the leaching properties of the filter material and the safety of using the material for water treatment. The test showed that leaching of metals, such as Cu, occurs, although at levels below the US EPA MCL limits. The DOC concentration in the leachate from pine bark was 69 mg/l (SD = 0.62). Phenols were measured to 4.4 mg/l (SD=0.35), which represents 7% of the DOC. 24 h and 48 h EC50 values for acute toxicity of leachates without pH adjustment to Daphnia magna were determined to 38% and 42% leachate concentration, respectively. All the test organisms were immobilised in the batch test with 100 % of the leachate concentration. The pH adjusted leachate samples showed no toxicity to Daphnia magna during 24 h or 48 h exposure. Subsequently, a tentative study with serial batch leaching tests was performed to further investigate the extent and duration of the leaching of organic material from the unused filter material. The preliminary results from the serial batch leaching showed that pH of the leachates decreased to below 5 even after three successive rounds of leaching of the pine bark. Desorption of DOC was not reduced by serial leaching of the filter material and did not appear to correlate with the observed decrease in toxicity after sequential leaching rounds. The toxicity of leachates from the untreated, unused filter material decreases after the first initial flush of water through the filter. There is a trend of reduced toxicity after each successive round of leaching for the 48 hour exposure of Daphnia magna to the leachates. All the test organisms were immobilised in the batch test with 100 % of the leachate concentration. Future research will focus on further investigation of the initial leaching duration and on chemical characterization of the leachate, with an emphasis on organic compounds.

  • 81.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Ecotoxicological assessment of anaerobic bioremidiation of sludge contaminated by the explosive 2,4,6-trinitrotoluene (TNT)2007Conference paper (Refereed)
  • 82.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Berglind, Rune
    FOI CBRN Defence and Security, Swedish Defence Research Agency.
    ECOTOXICOLOGICAL INVENTORY OF A CONTAMINATED EXPLOSIVES DESTRUCTION SITE2010In: :  , 2010Conference paper (Refereed)
  • 83.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Berglind, Rune
    FOI CBRN Defence and Security, Swedish Defence Research Agency.
    HAZARD SCREENING BY CHEMICAL ANALYSIS AND ECOTOXICITY BIOASSAYS OF SEDIMENT, GROUND AND SURFACE WATER SAMPLED FROM A FIRE POND AND THE SURROUNDING AREA AT AN EXPLOSIVES DESTRUCTION SITE2010In: Crete 2010, 2nd International Conference, Hazardous and Industrial Waste Management, Proceedings / [ed] E. Gidarakos; R. Cossu; R. Stegmann, 2010, p. 243-244Conference paper (Refereed)
    Abstract [en]

    A hazard assessment of sediment, surface and groundwater samples from the burning ground fire pond and the wetland linking the fire pond with a nearby lake at an explosives destruction site was carried out. The assessment was performed on sediment, surface and groundwater samples from the site by a comparison of the results from a chemical analysis (metals, energetic materials (EM) and EM metabolites) with the results from an ecotoxicity test battery. Sediment and water samples were analysed for metals (ICP-MS) and EM and EM metabolites (HPLC-PDA). The explosive substances analysed were TNT, 2-A-4,6-DNT, 2,4-DANT, 2,4-DNT, RDX and HMX. An aquatic ecotoxicity test battery consisting of an acute luminescent bacteria bioassay using (Vibrio fischeri), a direct-contact sediment chronic freshwater benthic crustacean bioassay (Ostracodtoxkit) and a bacterial genotoxic bioassay, Umu-C, using genetically modified Salmonella typhimurium pSk 1002 assessed the toxicity of water, sediment and sediment leachate samples. The results from the chemical analysis and the ecotoxicity testing were evaluated in a principal component multivariate analysis (PCA) using Unscrambler®. The results from the chemical analysis generally showed low contamination levels, apart from samples 2W and 2S, sampled in the fire pond. The toxicity tests showed a low to very low toxicity of the samples, with the exception of an elevated mortality rate and growth inhibition of the sediment sample taken from the lake. In general, the results from the study indicated a low environmental hazard of the samples taken from the destruction site.

  • 84.
    Schwede, Sebastian
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Anbalagan, Anbarasan
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Krustok, Ivo
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Lindberg, Carl-Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB Corporate Research, Västerås, Sweden.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Evaluation of the microalgae-based activated sludge (MAAS) process for municipal wastewater treatment on pilot scale2016Conference paper (Refereed)
    Abstract [en]

    The microalgae-based activated sludge (MAAS) process was evaluated regarding the removal efficiency of organic matter and nitrogen from physiochemically pretreated municipal wastewater at different hydraulic retention time (HRT) on pilot scale. Additionally, the interplay between the algal and bacterial consortium was evaluated regarding the ability of the algal consortium to provide oxygen for bacterial oxidation processes. The results showed in general high organic matter (COD removal 75-90%) and total nitrogen (40-50%) removal at all HRTs (6, 4 and 2 days). The dissolved oxygen (DO) concentration was maintained stable at 6 days (6.04±0.47 mg L-1) and 4 days (4.24±0.62 mg L-1) HRT. However, the DO significantly declined at 2 days HRT due to loss of biomass at the high influent flow in the sedimentation unit. Nevertheless, the MAAS process functioned as a symbiotic algal-bacterial system with bacterial organic matter oxidation and nitrification and algal nutrient removal.

  • 85.
    Sylwan, Ida
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zambrano, Jesús
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Removal of metals for improvement of sludge quality, adsorption to primary sludge during primary settlement2017Conference paper (Other academic)
    Abstract [en]

    The primary and secondary sludge from a wastewater treatment plant are generally mixed and treated combined. Here we introduce an idea for a process concept where the sludge flows are separated and the treatment of primary sludge is modified, with the goal to concentrate micropollutants in primary sludge while nutrients are removed in the secondary (biological) treatment to produce a “bio-sludge” with low metal contents. The example is based on primary settlement and an activated sludge process. In contrast to a conventional process, the sludge flows are as mentioned separated. After anaerobic digestion and dewatering, primary sludge goes through pyrolysis. Biochar produced during pyrolysis is added in pulverized or granulated form to the primary settler. The hypothesis is that biochar will adsorb dissolved metals and thus enhance the metal removal in primary treatment. The biochar should settle with primary sludge, and pyrolysis is repeated. However, to remove metal content from the system some portion of the produced biochar will have to be removed in each cycle. A prerequisite for nutrients to end up in the bio-sludge is that chemical coagulants are not used in primary treatment and that there is no recirculation of sludge from secondary to primary treatment. To the best of the authors knowledge, biochar has not previously been tested as an adsorbent in primary treatment of wastewater. Efficient removal of metals has though been shown in several studies where wastewater was filtrated through biochar in granulated form (Huggins et al., 2016). Further, biochar has been shown to sorb pharmaceuticals from urine without removing nutrients (Solanki & Boyer, 2017). In this paper, results from experimental tests on addition of biochar in the primary settler will be presented. Experiments are made in lab-scale to test the adsorption and settling capacity depending on biochar properties, e.g. particle size, cation exchange capacity. The theoretical dosing requirement in a full scale application and possible biochar yields from pyrolysis of primary sludge are also investigated.

  • 86.
    Thorin, Eva
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Olsson, Jesper
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Biogas from Co-digestion of Sewage Sludge and Microalgae2017In: Energy Procedia, 2017, Vol. 105, p. 1037-1042Conference paper (Refereed)
    Abstract [en]

    Microalgae cultivated in waste water could contribute to increased biomass production at municipal waste watertreatment plants. The biomass could be utilized for biogas production when co-digested with sewage sludge. In thispaper previous published results on co-digestion of sewage sludge and microalgae are summarized and remainingknowledge gaps are identified. The available batch tests in literature mostly concern digestion at mesophilicconditions. Some of those tests indicate a synergetic effect for the co-digestion. Investigations at thermophilicconditions and of semi-continuous processes are scarce. The available results show good possibilities for co-digestionof sewage sludge and microalgae. Further investigations are needed to find optimal conditions for biogas production.

  • 87.
    Thorin, Eva
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Olsson, Jesper
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Co-digestion of sewage sludge and microalgae: Biogas production investigations2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 227, p. 64-72Article in journal (Refereed)
    Abstract [en]

    In municipal wastewater treatment plants (WWTPs), algae could be utilised for cleaning the water and, at thesame time, produce a biomass that can be used for energy. Through anaerobic digestion, microalgae can contributeto biogas production when co-digested with sewage sludge. In this paper, previous published results onthe co-digestion of sewage sludge and microalgae are summarised and reviewed, and any remaining knowledgegaps are identified. The batch tests currently documented in literature mostly concern digestion under mesophilicconditions, and studies investigating thermophilic conditions are less common. The average biochemicalmethane potential (BMP) for 29 different mixtures co-digested under mesophilic conditions is 317 ± 101 N cm3CH4 gVS−1 while the result for 12 different mixtures investigated under thermophilic conditions is a BMP of318 ± 60 N cm3 CH4 gVS−1. An evaluation of the heat required for increasing the temperature from mesophilicto thermophilic conditions shows that increased methane production under thermophilic conditions can beenough to create a positive energy balance. For a full-scale WWTP, using thermophilic digestion on sludge, or acombination of sludge and microalgae could therefore be of interest. This is dependent on the demands onsanitation of the sludge and the possibilities for heat recovery.Most of the mesophilic investigations indicate a synergetic effect for co-digestion, with enhancements of up toalmost 70%. However, the results are uncertain since the standard deviations for some of the BMP tests are in thesame order of magnitude as the identified enhancement. Neither of the presented publications provide an understandingof the basic mechanisms that led to higher or lower BMP when microalgae were mixed with wastewatersludge. We, therefore, call for care to be taken when assuming any effects related to the specification ofsubstrates. Microalgae and wastewater sludge have several similarities, and the specific results of BMP in themixtures relate more to the specifics of the respective materials than the materials themselves.Investigations into semi-continuous processes of co-digestion of microalgae and sludge are scarce. The yieldsfor three co-digestion studies show high variation, with an average of 293 ± 112 N cm3 gVSin−1. The availableresults show strong potential for co-digestion of sewage sludge and microalgae. Further investigations are requiredto identify optimal conditions for biogas production, and analysis of microalgae implementation onwastewater treatment at a system level is also needed to identify the total mass balance of substrate and nutrientrecovery.

  • 88.
    Zambrano, Jesús
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Carlsson, Bengt
    Uppsala University, Sweden.
    Diehl, Stefan
    Lund University, Sweden.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    A Simplified Model of an Activated Sludge Process with a Plug-Flow Reactor2016Conference paper (Refereed)
    Abstract [en]

    The analysis of a simplified activated sludge process (ASP) with one main dissolved substrate and one main particulate biomass component has been conducted with respect to its steady-state. The ASP is formed by a plug flow reactor (PFR) and a settler with the recycling going to the reactor. The biomass growth rate is described by a Monod function. For this process, it is not possible to get an explicit expression for the effluent substrate concentration when the process is subject to a fixed sludge age. However,in the normal case when the influent substrate concentration is much greater than the effluent substrate concentration, then an explicit approximation for the effluent as a function of the influent and the process parameters is obtained. This work includes numerical examples considering two models for the settler. One model is the ideal settler, which assumes a complete thickening of the activated sludge through the underflow of the settler. The other model takes into account hindered settling and sludge compression. Numerical results show the effectiveness and the limitations of the proposed solution under these scenarios.

  • 89.
    Zambrano, Jesús
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Krustok, Ivo
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Carlsson, Bengt
    Department of Information Technology, Uppsala University, Uppsala, Sweden.
    A simple model for algae-bacteria interaction in photo-bioreactors2016In: Algal Research, ISSN 2211-9264, Vol. 19, no nov, p. 155-161Article in journal (Refereed)
    Abstract [en]

    This work presents a simple model to describe the consortia of algae-bacteria in a photo-bioreactor. The model is inspired by the Activated Sludge Model (ASM) structure, which includes different process rates and stoichiometric parameters. The model comprises two main biomass populations (algae and bacteria), two dissolved substrates (ammonium and nitrate) and two dissolved gases (oxygen and carbon dioxide) in the reactor. The model was calibrated with data from batch experiments performed in two lab-scale photo-bioreactors. A sensitivity analysis was done to identify the parameters to be considered for the model calibration. Results indicate that the maximum algae and bacteria growth rate, bacteria growth yield and half-saturation constant for carbon were the most sensitive parameters. Moreover, the comparison between the experiments and the model shows good agreement in terms of predicting the ammonium, nitrate and oxygen concentrations in the photo-bioreactor.

  • 90.
    Zambrano, Jesús
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Light and duty cycle optimization of a photo-bioreactor in batch mode2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 773-779Article in journal (Refereed)
    Abstract [en]

    This paper is focused on optimizing the amount of light duty cycle of a photo-bioreactor operating in batch mode. The mathematical model used is confined to one dissolved substrate, one biomass (algae), one internal cell quota, and the irradiance for photo-acclimated culture. The model has been previously published and validated with experimental data. The following optimization problem is studied: minimize the effluent substrate concentration subject to: maximum and minimum amount of light to be used, the time of the light/dark illumination and the total time of the batch experiment. Analytical solution for this optimization problem seems difficult to obtain. However, numerical results obtained from simulations show that it is possible to find solutions which satisfy the problem requirements.

  • 91.
    Zambrano, Jesús
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Microalgae Activated Sludge: Process Modelling and Optimization2017Conference paper (Refereed)
    Abstract [en]

    This work deals with steady-state optimization of a process formed by an algae-bacteria photo-bioreactor (PBR) in an activated sludge configuration. The optimization is done by considering the total PBR volume as two volumes in series, and aiming for the minimal nitrogen concentration in the effluent, for a given external light and carbon dioxide (CO2) injection. Results suggest that it is possible to obtain an optimum volume distribution that gives a lower effluent substrate concentration compared to a single volume, and this optimum volume depends on the CO2 applied.

12 51 - 91 of 91
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