| 1. |
- Munthe, Christian, 1962
(författare)
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Precaution and Ethics: Handling risks, uncertainties and knowledge gaps in the regulation of new biotechnologies
- 2017
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This volume outlines and analyses ethical issues actualized by applying a precautionary approach to the regulation of new biotechnologies. It presents a novel way of categorizing and comparing biotechnologies from a precautionary standpoint. Based on this, it addresses underlying philosophical problems regarding the ethical assessment of decision-making under uncertainty and ignorance, and discusses how risks and possible benefits of such technologies should be balanced from an ethical standpoint. It argues on conceptual and ethical grounds for a technology neutral regulation as well as for a regulation that not only checks new technologies but also requires old, inferior ones to be phased out. It demonstrates how difficult ethical issues regarding the extent and ambition of precautionary policies need to be handled by such a regulation, and presents an overarching framework for doing so.
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| 2. |
- Wu, Xue, 1986, et al.
(författare)
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Ammonium recovery from reject water combined with hydrogen production in a bioelectrochemical reactor
- 2013
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 146, s. 530-536
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a bioelectrochemical reactor was investigated for simultaneous hydrogen production and ammonium recovery from reject water, which is an ammonium-rich side-stream produced from sludge treatment processes at wastewater treatment plants. In the anode chamber of the reactor, microorganisms converted organic material into electrical current. The electrical current was used to generate hydrogen gas at the cathode with 96±6% efficiency. Real or synthetic reject water was fed to the cathode chamber where proton reduction into hydrogen gas resulted in a pH increase which led to ammonium being converted into volatile ammonia. The ammonia could be stripped from the solution and recovered in acid. Overall, ammonium recovery efficiencies reached 94% with synthetic reject water and 79% with real reject water. This process could potentially be used to make wastewater treatment plants more resource-efficient and further research is warranted.
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| 3. |
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| 4. |
- Mårtensson, Lennart, 1957-, et al.
(författare)
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Biomass from wetlands and other valuable conservation areas as substrate for industrial biotechnology
- 2016
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Ingår i: The Ninth International Conference on the Establishment of Cooperation between Companies and Institutions in the Nordic Countries, the Baltic Sea Region, and the World. - 9789188357410
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Konferensbidrag (refereegranskat)abstract
- Biomass from wetlands has historically been an important resource, but today it is difficult to take advantage of this biomass, besides being used as feed on the farm. A very important goal is to find rational and economical viable way to make biogas from wetland biomass, including biomass from other conservation worthy areas of high biodiversity, such as roadsides harvested frequently. Moreover, the residues from biogas process used as bio-fertilizer to the fields, so that nitrogen and phosphorus is returned to the farm land. The biomass can be used for the production of biogas or for extracting valuable chemicals in bio refineries. These valuable chemicals may be potentially useful for making future plastic materials, i.e. bio plastics. Major focus will be on biogas technology, and above all, methods for the pretreatment of recalcitrant substrates such as biomass containing high levels of lignocelluloses, i.e., to make the material available to the biogas-producing bacteria. The work is based on an involvement of research in the areas of environmental engineering and landscape science and includes studies of biodiversity and water treatment function of the landscape. Finally, it is important to stress that mowing of wet meadows mostly will result in a better capacity of such meadows to retain nutrients from water passing through them. Wetland with wet meadows and similar vegetation types will be more efficient in cleaning water and thereby fight eutrophication in the recipient. Summing up, the main advantages using harvest hay (mowing) from wet meadows and roadside meadows as substrate for biotechnical industry are:•Raw material for bio plastics•Cheap and easy handled fertilizers to agriculture•Important for biodiversity•Better function of wetlands as nutrient traps fighting eutrophication of the sea
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| 5. |
- Soam, Shveta, 1987-, et al.
(författare)
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Life cycle assessment of rice straw utilization practices in India
- 2017
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 228, s. 89-98
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to find potential utilization practice of rice straw in India from an environmental perspective. Life cycle assessment (LCA) is conducted for four most realistic utilization practices of straw including: (1) incorporation into the field as fertilizer (2) animal fodder (3) electricity (4) biogas. The results show that processing of 1 ton straw to electricity and biogas resulted in net reduction of 1471 and 1023 kg CO2 eq., 15.0 and 3.4 kg SO2 eq. and 6.7 and 7.1 kg C2H6 eq. emissions in global warming, acidification and photochemical oxidation creation potential respectively. Electricity production from straw replaces the coal based electricity and resulted in benefits in most of the environmental impacts whereas use as an animal fodder resulted in eutrophication benefits. The burning of straw is a harmful practice of managing straw in India which can be avoided by utilizing straw for bioenergy.
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| 6. |
- Rämö, Robert, et al.
(författare)
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Sediment Remediation Using Activated Carbon: Effects of Sorbent Particle Size and Resuspension on Sequestration of Metals and Organic Contaminants.
- 2022
-
Ingår i: Environmental toxicology and chemistry. - : Wiley. - 1552-8618 .- 0730-7268. ; 41:4, s. 1096-1110
-
Tidskriftsartikel (refereegranskat)abstract
- Thin-layer capping using activated carbon (AC) has been described as a cost-effective in situ sediment remediation method for organic contaminants. In this study, we compare the capping efficiency of powdered AC (PAC) against granular AC (GAC) using contaminated sediment from Oskarshamn harbor, Sweden. The effects of resuspension on contaminant retention and cap integrity were also studied. Intact sediment cores were collected from the outer harbor and brought to the laboratory. Three thin-layer caps, consisting of PAC or GAC mixed with clay, or clay only, were added to the sediment surface. Resuspension was created using a motor-driven paddle to simulate propeller wash from ship traffic. Passive samplers were placed in the sediment and in the water column to measure the sediment-to-water release of PAHs, PCBs, and metals. Our results show that a thin-layer cap with PAC reduced sediment-to-water fluxes of PCBs by 57 % under static conditions and 91 % under resuspension. Thin-layer capping with GAC was less effective than PAC, but reduced fluxes of high-molecular weight PAHs. Thin-layer capping with AC was less effective in retaining metals, except for Cd, which release was significantly reduced by PAC. Resuspension generally decreased water concentrations of dissolved cationic metals, perhaps due to sorption to suspended sediment particles. Sediment resuspension in treatments without capping increased fluxes of PCBs with log Kow > 7 and PAHs with log Kow 5 6, but resuspension reduced PCB and PAH fluxes through the PAC thin-layer cap. Overall, PAC performed better than GAC, but adverse effects on the benthic community and transport of PAC to non-target areas are drawbacks that favor the use of GAC. This article is protected by copyright. All rights reserved.© 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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| 7. |
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| 8. |
- Hai, Faisal Ibney, et al.
(författare)
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Application of membrane technology for the development of sustainable biotechnology processes
- 2013
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Ingår i: Membrane Processes for Sustainable Growth. ; , s. 193-224
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The scope of application of membranes in biotechnology has widened significantly in the recent years. Although many of the membrane options are yet to achieve wide industrial applications, they show tremendous potential for the transformation and synthesis of value-added products, energy production, therapeutic applications and environmental remediation. This chapter provides an overview of membrane applications in selected established and emerging biotechnology processes. Approaches to overcoming the technology bottlenecks that impede the scale-up of such systems have been discussed in this chapter.
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| 9. |
- Hai, Faisal Ibney, et al.
(författare)
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Biocatalytic membrane reactors for the removal of recalcitrant and emerging pollutants from wastewater
- 2013
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Ingår i: Handbook of Membrane Reactors Volume 2: Reactor types and industrial applications. - : Elsevier. ; 2, s. 763-807
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The potential fields of application of the biocatalytic membrane reactors have widened considerably in the recent years. Although biocatalytic membrane reactors, in general, are yet to achieve broad industrial applications, in the not too far future, they are expected to play a major role not only for the production, transformation and valorization of raw materials but also for environmental remediations. This chapter comprehensively reviews the laboratory scale studies which demonstrate the potential of biocatalytic membrane reactors in wastewater treatment applications. Studies reported in the literature, however, serves as proof of concept only. Issues that need to be addressed in order to achieve scale-up of such systems have been discussed in this chapter.
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| 10. |
- Kharazmi, Parastou, 1977-
(författare)
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Evaluation of Innovative Rehabilitation Technologies Utilising Polymer Composites for Aging Sewer Systems
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Water and wastewater sewer system maintenance is among the costliest aspects of infrastructure investment. The replacement of deteriorated lines is a difficult and expensive process that causes community disturbance and is generally not conducted fast enough to meet demand. To keep up with the rate of deterioration, the use of alternative rehabilitation technologies using polymer linings has increased significantly in recent years, both within Sweden and worldwide. Compared to the traditional pipe replacement method, these technologies are cost-effective, create less community disturbance, and offer a quick return to the service for the line. The main function of polymeric lining is to stabilise the condition of the pipeline, eliminate deterioration, and thereby extend the pipeline’s service life. Although rehabilitation technologies employing polymeric systems have been in use for over 30 years, there have been few technical assessments of either these technologies or the materials involved. Data gathered through the evaluation of these innovative technologies can make their benefits and limitations more widely understood, and can also be used to increase the effectiveness of the rehabilitation process in future.The main objective of this work was to contribute to an improved understanding of the most commonly used materials and methods employed in rehabilitation of wastewater and other applicable sewer lines in residential buildings in Sweden. The primary objective was not to prove that the emerging rehabilitation technologies work, but rather to increase knowledge of their weaknesses and strengths, identify any issues, and provide a technical assessment to support realistic expectations of pipeline rehabilitation. Gathering technical information in this way will help with the planning of future investigations; moreover, collecting extensive data will help to increase the effectiveness of the renewal works, aid progress in the field, and improve predictions regarding longevity and service life. As pipeline rehabilitation is still considered novel, and owing to the general lack of available data on the subject, a multi-approach study was carried out: this included evaluation of the polymeric materials’ performance in the presence of deteriorative factors, assessing the in-service state of the materials and lined sewers previously installed, monitoring the level of quality control implemented during previous rehabilitation works, and evaluating the environmental impacts of using pipe-lining technologies compared to pipe replacement. The techniques discussed included rehabilitation with epoxy and polyester resin-based lining materials, applied with brush-on and spray-on techniques, and cured-in-place pipe lining (installed by sending a resin-impregnated flexible tube inside the host pipe). Degradation of the resin-based lining materials was investigated via artificial aging involving immersion in water at elevated temperatures. The changes in materials that occurred during accelerated laboratory aging were tracked by means of various tests, including thermal and mechanical analyses, water absorption measurements and microscopy. The analysis focused on reinforced polyester-based and toughened epoxy-based lining materials in order to gain a better understanding of their performance as pipe lining. Moreover, the previously installed lined pipes and lining materials were also studied during laboratory examinations to evaluate the in-service performance of the materials and techniques under operating conditions over time, as well as to identify common defects. The state of the materials and the lined pipe were studied by means of different investigative methods, including visual inspection, microscopy, Fourier transform infrared spectroscopy, thickness measurement, thermal and mechanical analyses. This PhD work also includes an investigation to determine the level of quality control carried during some previous rehabilitation works. Data on the quality evaluation of previous rehabilitation works were gathered during visits to the work sites, as well as by analysing lined pipes that had already been installed. Finally, a comparative life-cycle assessment was undertaken to compare the environmental impacts of pipe replacement with those of alternative innovative rehabilitations, such as CIPP and coatings with polyester and epoxy polymeric systems. Data obtained from an LCA tool were used to facilitate comparison from an environmental perspective.Results from artificial aging in the lab indicated that the properties of polymeric lining materials changed significantly when high temperatures were combined with water exposure. However, the aging testing conducted for this study also found that the materials performed relatively well at temperatures close to the average temperatures inside sewerage systems. The results revealed that the polyester-based lining material was less sensitive when compared with epoxy-based lining materials during stimulated aging. Moreover, results from the in-service field demonstration (involving examination of 12 samples with up to 10 years of service, including reinforced polyester and modified epoxy linings or cured-in-place pipe (CIPP) lining) showed minimal evidence that the materials underwent significant deterioration after installation; instead, a majority of the common defects were found to be related to poor-quality installation practices. Because very few field samples were available to study, conclusions regarding overall performance could not be drawn. However, there is no evidence that these materials will not perform as expected during their service life when properly installed.Evaluating quality control of previous rehabilitation work revealed a gap between theory and practice where the level of quality control and documentation was concerned; furthermore, it also emerged that quality control and documentation is crucial to both the prevention of common issues and the overall effectiveness of the rehabilitation. Accordingly, a series of recommendations regarding the development of comprehensive quality control and quality assurance procedures (QC/QA) are provided in this work. These recommendations highlight the aspects that are most important to consider at each of several key stages (before installation, during installation, and after rehabilitation work is completed).Results from comparative life-cycle assessment (LCA) showed that alternative technologies, including cured-in-place (flexible sleeve) and coating techniques, have some advantages over pipe replacement from an environmental perspective. However, the choice to use one rehabilitation technology over another is a multi-stage decision-making process that should not be based solely on a single factor.This PhD work promotes an improved understanding of the limitations and benefits of polymeric lining through the testing performed and analyses conducted. This work highlights the need for improved quality control, and further suggests that developing a detailed and comprehensive quality control plan for each technology would provide higher and more consistent quality overall. The study also demonstrates that the long-term strength of any rehabilitation work depends on various factors, and that selecting one method over another must be a process based on extensive knowledge and understanding of each rehabilitation technology. No evidence was found to indicate that the materials could not perform well under working conditions if selected and installed appropriately. However, a larger number of field samples with longer in-service time and a more detailed technical history, along with a more extended experimental plan for laboratory investigations based on the results of this PhD work, will allow for the gathering of the data required to answer questions regarding life expectancy with a higher degree of certainty.
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| 11. |
- Modin, Oskar, 1980
(författare)
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A mathematical model of aerobic methane oxidation coupled to denitrification
- 2018
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Ingår i: Environmental Technology (United Kingdom). - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 39:9, s. 1217-1225
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Tidskriftsartikel (refereegranskat)abstract
- Aerobic methanotrophic bacteria use methane as their only source of energy and carbon. They release organic compounds that can serve as electron donors for co-existing denitrifiers. This interaction between methanotrophs and denitrifiers is known to contribute to nitrogen losses in natural environments and has also been exploited by researchers for denitrification of nitrate-contaminated wastewater. The purpose of this study was to develop a mathematical model describing aerobic methane oxidation coupled to denitrification in suspended-growth reactors. The model considered the activities of three microbial groups: aerobic methanotrophs, facultative methylotrophs, and facultative heterotrophs. The model was tested against data from the scientific literature and used to explore the effects of the oxygen mass transfer coefficient, the solids retention time, and the fraction methane in the feed gas on nitrate removal. The fraction of methane in the feed gas was found to be critical for the nitrate removal rate. A value of about 15% in air was optimal. A lower methane fraction led to excess oxygen, which was detrimental for denitrification. A higher fraction led to oxygen-limitation, which restricted the growth rate of methanotrophs in the reactor.
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| 12. |
- Modin, Oskar, 1980, et al.
(författare)
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Hill-based dissimilarity indices and null models for analysis of microbial community assembly
- 2020
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Ingår i: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundHigh-throughput amplicon sequencing of marker genes, such as the 16S rRNA gene in Bacteria and Archaea, provides a wealth of information about the composition of microbial communities. To quantify differences between samples and draw conclusions about factors affecting community assembly, dissimilarity indices are typically used. However, results are subject to several biases, and data interpretation can be challenging. The Jaccard and Bray-Curtis indices, which are often used to quantify taxonomic dissimilarity, are not necessarily the most logical choices. Instead, we argue that Hill-based indices, which make it possible to systematically investigate the impact of relative abundance on dissimilarity, should be used for robust analysis of data. In combination with a null model, mechanisms of microbial community assembly can be analyzed. Here, we also introduce a new software, qdiv, which enables rapid calculations of Hill-based dissimilarity indices in combination with null models.ResultsUsing amplicon sequencing data from two experimental systems, aerobic granular sludge (AGS) reactors and microbial fuel cells (MFC), we show that the choice of dissimilarity index can have considerable impact on results and conclusions. High dissimilarity between replicates because of random sampling effects make incidence-based indices less suited for identifying differences between groups of samples. Determining a consensus table based on count tables generated with different bioinformatic pipelines reduced the number of low-abundant, potentially spurious amplicon sequence variants (ASVs) in the data sets, which led to lower dissimilarity between replicates. Analysis with a combination of Hill-based indices and a null model allowed us to show that different ecological mechanisms acted on different fractions of the microbial communities in the experimental systems.ConclusionsHill-based indices provide a rational framework for analysis of dissimilarity between microbial community samples. In combination with a null model, the effects of deterministic and stochastic community assembly factors on taxa of different relative abundances can be systematically investigated. Calculations of Hill-based dissimilarity indices in combination with a null model can be done in qdiv, which is freely available as a Python package (https://github.com/omvatten/qdiv). In qdiv, a consensus table can also be determined from several count tables generated with different bioinformatic pipelines.
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| 13. |
- Modin, Oskar, 1980, et al.
(författare)
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Three promising applications of microbial electrochemistry for the water sector
- 2017
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Ingår i: Environmental Science: Water Research and Technology. - : Royal Society of Chemistry (RSC). - 2053-1419 .- 2053-1400. ; 3:3, s. 391-402
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Tidskriftsartikel (refereegranskat)abstract
- Microbial electrochemical technologies are based on the interactions between living microorganisms and electrodes. There is a wide range of possible applications and many are highly relevant for the water sector. The most well-known is probably the microbial fuel cell, which has been proposed as an environmentally-friendly process for simultaneous wastewater treatment and electrical energy production. However, fullscale implementation at wastewater treatment plants is very challenging and there are several other applications of microbial electrochemistry that are less well-known to people outside the research field, but potentially could be widely applied and make an impact on the water sector in a shorter time perspective. In this paper, we highlight three such applications: (i) sensors for biochemical oxygen demand, volatile fatty acids and toxicity; (ii) in situ bioremediation of contaminated sites; and (iii) removal and recovery of metals from wastewaters, leachates and brines.
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| 14. |
- Pawar, Sudhanshu S., et al.
(författare)
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MultiBio: Environmental services from a multipurpose biorefinery
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- MultiBio project aimed to establish and demonstrate a novel multipurpose biorefinery cascade concept, producing three renewable biobased products: 1) biohydrogen, 2) biopolymers and 3) protein rich meal ingredients for fish farming. The cascade concept exploits the ability of a bacterium (Caldicellulosiruptor saccharolyticus) to transform nutrients present in low-value waste process waters of the pulp and paper industry, to high-value products hydrogen gas, organic acids and microbial biomass. The organic acid rich effluent will then be managed in an open culture microbial process used to achieve discharge water quality objectives and to produce polyhydroxyalkanoate (PHA) biopolymers. Moreover, since C. saccharolyticus protein content is more than 63% of cell dry weight, their potential in formulation of fish feed was evaluated. A fiber sludge containing, CTMP residual stream was found to be a possible feedstock for the MultiBio process concept. Due to safety risks the demo-scale experiments of biohydrogen gas technology were moved from Biorefinery demo plant (Örnsköldsvik) of 40 m3 capacity to ATEX classified pilot-scale facility with 0.4 m3 capacity. Hence, bacterial biomass enough for the large-scale fish feed ingredient could not be produced. Lab-scale experiments with Caldicellulosiruptor cells as fish feed ingredient showed promising results as a protein-rich, sustainable fish feed ingredient. In addition, PHA biopolymer also showed favourable results as fish food ingredient for experiments at Gårdsfisk AB. Lab-scale experimental tests showed that the surplus activated sludge from the mills wastewater treatment could currently accumulate PHA to about 20 % of its dry weight. Mass balance evaluations based on realistically achievable expectations indicated a PHA biopolymer production potential of 3 600 tons of PHA per year from available organic residuals and for the two evaluated mills combined. The MultiBio concept has a positive climate impact in comparison with current treatment and moves developments in a positive direction to achieve 7 of the 10 Swedish environmental goals. Through a detailed feasibility analysis, a natural progression in next steps in scenarios were suggested for PHA production. The MultiBio cascade process can be implemented with further necessary development with good business potential and a positive effect on climate change. However, biohydrogen technology needs further developments before this cascade process concept can be implemented. Alternatively, a scenario with only biopolymer technology shows already a significant business potential and even larger positive effect on climate change. A successful next step in demonstration of the PHA biopolymer production scenario may lead to it being implemented within the next few years. Furthermore, MultiBio has attracted a lot of attention regionally and nationally but also internationally with a total of 65 media listings. A licentiate thesis and three university degree projects linked to the project have been completed. Overall, the MultiBio project has successfully achieved its goals and objectives.
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| 15. |
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| 16. |
- Timmusk, Salme, et al.
(författare)
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Sfp-type PPTase inactivation promotes bacterial biofilm formation and ability to enhance wheat drought tolerance
- 2015
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Paenibacillus polymyxa is a common soil bacterium with broad range of practical applications. An important group of secondary metabolites in P polymyxa are non-ribosomal peptide and polyketide derived metabolites (NRPs/PKs). Modular non-ribosomal peptide synthetases catalyze main steps in the biosynthesis of the complex secondary metabolites. Here we report on the inactivation of an A26 Sfp-type 4'-phosphopantetheinyl transferase (Sfp-type PPTase). The inactivation of the gene resulted in loss of NRPs/PKs production. In contrast to the former Bacillus spp. model the mutant strain compared to wild type showed greatly enhanced biofilm formation ability. A26 Delta sfp biofilm promotion is directly mediated by NRPs/PKs, as exogenous addition of the wild type metabolite extracts restores its biofilm formation level. Wheat inoculation with bacteria that had lost their Sfp-type PPTase gene resulted in two times higher plant survival and about three times increased biomass under severe drought stress compared to wild type. Challenges with P. polymyxa genetic manipulation are discussed.
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| 17. |
- Wadström, Christoffer, et al.
(författare)
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Exploring total economic values in an emerging urban circular wastewater system
- 2023
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Ingår i: Water Research. - : Elsevier BV. - 1879-2448 .- 0043-1354. ; 233
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Forskningsöversikt (refereegranskat)abstract
- Circular water management has the potential to close resource and material loops within and across value chains. In the water industry, circular municipal wastewater management through industrial urban symbiosis (IUS) is recognized as a solution to overcome water scarcity in urban environments. IUS involves collaboration between actors with different organizational backgrounds, which can lead to inherent risks of conflicting goals. This study explores how different values drive various organizations to participate in an emerging circular wastewater collaboration. The study comprises a literature review of 34 scientific articles and a case study of a potential circular wastewater system through IUS in Simrishamn, Sweden. It presents an interdisciplinary framework based on the total economic value concept and organizational archetypes for examining actor values in circular wastewater management. This framework provides a novel approach for assessing different values and how they may compete or align. It can also identify the absence of certain values, enabling the achievement of a minimum level of value coherence amongst different actors, and thereby increasing the sustainability and effectiveness of circular wastewater collaborations. Therefore, careful planning and stakeholder interaction, in accordance with economic value perspectives, can enhance the legitimacy and policy development of circular solutions.
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| 18. |
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| 19. |
- Knutsson, Pavleta, 1980, et al.
(författare)
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Phycoremediation of heavy metals in ashes
- 2014
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Ingår i: Chalmers Life Science Area of Advance Meeting, May 5, Göteborg.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A growing problem in today’s society is the increasing amount of ash from the production of electricity and heat. Ash contains heavy metals that may be harmful to the environment. By using algae as ion exchangers, the ashes can be purified from certain heavy metals before deposit and its environmental impact is decreased [1]. Algal cell wall contains functional groups, such as amino-, carboxyl-, hydroxyl- and suphate groups, to which the various metal ions can bind bind [3]. An ion exchange of bound metal ions toward heavy metal ions can occur when the cell wall comes in contact with, for example, leachate from the ashes [1]. The process of using algae for environmental remediation is called phycoremediation.Within this project, we study the potential of microalgae for remediating ash from heavy metals, by measuring the metal binding capacity by three phytoplankton species: Chlorella salina, Dunaliella salina and Scendesmus obliquus. The heavy metals assayed are divalent ions of mercury (Hg), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn). The effect of pH has been investigated as well as total binding over time. To apply the method on a more authentic situation, the binding of metals from combustion ash was investigated.
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| 20. |
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| 21. |
- Abadikhah, Marie, 1992
(författare)
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Influence of electrode material and stochastic factors on the performance and microbial community assembly in microbial electrochemical systems
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Microbial electrolysis cells (MECs) are systems with microbial communities in the form of biofilms on electrode surfaces. The electrogenic bacteria in the anode biofilm act as catalysts for the oxidization of organic compounds, leading to release of electrons, generation of electrical current, and production of hydrogen and methane at the cathode. In addition to production of energy carriers, MECs can be used for other applications as well; for example, as biosensors to monitor biochemical oxygen demand or toxicity. The performance of MECs is determined by both deterministic and stochastic factors influencing the microbial communities on the electrode surfaces, most of which as still poorly understood. In this thesis, the effects of electrode materials on microbial community assembly and MEC performance was investigated. Two experiments were carried out. In the first, three cathode materials (carbon nanoparticles, titanium, and steel) were compared. In the second, three anode materials (carbon cloth, graphene, and nickel) were compared. The cathode materials had no significant effect on the performance of the MECs, as opposed to the anode materials where carbon cloth MECs had the highest current density and the shortest lag time during startup. The differences seen in lag time of replicate systems at the start of the experiment indicated a stochastic initial attachment of the electrogenic bacteria on the anode. Different microbial communities develop in the biofilms on the anodes and cathodes. Electrogens from the Desulfobacterota phylum dominated the anode, while various hydrogenotrophic methanogens, e.g., Methanobacterium, were found to dominate on the cathodes. Diversity and null model analysis of the electrode communities highlighted stochasticity and not electrode material as the important factor in the community assembly. Network analysis showed that the cathode communities had fewer negative interactions between taxa in comparison to the anode. Since hydrogen gas generated at the cathode surface can diffuse through the biofilm, all microorganisms on the cathode have access to the substrate, reducing the need for competition between species. In contrast, electrogens require a short distance to the anode to be able to use it as electron acceptor. Limited space on the anode and competition between electrogens shaped the anode communities and explain the higher number of negative interactions observed. Based on the findings in this thesis, it is suggested that stochastic factors have more influence than electrode material on the anode community even though there is a selective pressure for electrogenic bacteria.
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| 22. |
- Albers, Eva, 1966, et al.
(författare)
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Influence of preservation methods on biochemical composition and downstream processing of cultivated Saccharina latissima biomass
- 2021
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 55
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Tidskriftsartikel (refereegranskat)abstract
- Saccharina latissima biomass cultivated along the Swedish west coast was subjected to four different scalable preservation methods after harvest; freezing, sun-drying, oven-drying and ensiling. Freeze-drying and freezing at -80 ?C were also included to provide dry and wet references. The effects of the different preservation methods on the composition of Saccharina biomass (on dry weight, DW, basis), and the recovery as well as properties of high-quality protein, alginate and biogas were evaluated. Sun-drying significantly reduced protein, alginate and fatty acid content of the seaweeds and thereby concentrated ash in the biomass compared to the other methods. Protein/amino acids and fatty acids were significantly concentrated in ensiled biomass, while mannitol and laminarin were reduced compared to the other biomasses. Oven-drying and -20 ?C freezing affected the composition the least, with lower ash content and alterations in some specific amino and fatty acids. Sun-drying and ensiling resulted in significantly lower protein solubility at high pH compared to the other biomasses which translated into the lowest total seaweed protein recovery using the pH-shift process. Highest protein yield was obtained with the freeze-dried reference. Ensiling lead to a significant decrease in the molecular weight of alginate, while sun-drying caused a negative effect on alginate by inducing a shift in the guluronic and mannuronic acids composition of alginate. Sun-drying gave the lowest methane yield in the anaerobic digestion experiments while freezing at -80 ?C gave the highest yield, closely followed by freezing at -20 ?C and ensiling. To conclude, preservation methods must be carefully chosen to protect the valuable component in Saccharina latissima, and to achieve an efficient downstream processing ultimately yielding high quality products as part of a seaweed biorefinery.
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| 23. |
- Bard, Sara, et al.
(författare)
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Pulp Wastewater Treatment Using Anaerobic Moving Bed Biofilm Reactors: A Case-Study
- 2024
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Ingår i: International Conference on Wider-Uptake of Water Resource Recovery from Wastewater Treatment, ICWRR 2024. - : Springer Nature. ; 524 LNCE, s. 234-239
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Konferensbidrag (refereegranskat)abstract
- The pulp and paper (P&P) industry holds significant global importance. However, the industry’s processes substantially demand water and energy resources. Consequently, there is a pressing need for the industry to adopt more sustainable production practices, aiming to trim environmental impact and strengthen resilience against climate change. Recent research has highlighted the potential for substantial increases in Swedish biogas production using anaerobic wastewater (WW) treatment methods within P&P mills. The P&P sector traditionally relies on aerobic biological WW treatment, overlooking the valuable opportunity for WW resource recovery. This study aims to evaluate anaerobic moving bed biofilm reactors (AnMBBR) to enhance energy recovery while enabling treatment capacity for the P&P industry’s anaerobic WW treatment. The results of this study showed the resilience of the AnMBBR system. It proved capable of recovering from overload conditions and operating even during prolonged periods at low pH levels. However, the system removes mainly soluble COD, suggesting higher capabilities on P&P WW with a high fraction of soluble COD. Its ability to produce methane-rich biogas demonstrates efficient gas production while maintaining simple operational procedures.
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| 24. |
- Beijer, Kristina, et al.
(författare)
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Removal of pharmaceuticals and unspecified contaminants in sewage treatment effluents by activated carbon filtration and ozonation : Evaluation using biomarker responses and chemical analysis
- 2017
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 176, s. 342-351
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Tidskriftsartikel (refereegranskat)abstract
- Traces of active pharmaceutical ingredients (APIs) and other chemicals are demonstrated in effluents from sewage treatment plants (STPs) and they may affect quality of surface water and eventually drinking water. Treatment of effluents with granular activated carbon (GAC) or ozone to improve removal of APIs and other contaminants was evaluated at two Swedish STPs, Kappala and Uppsala (88 and 103 APIs analyzed). Biomarker responses in rainbow trout exposed to regular and additionally treated effluents were determined. GAC and ozone treatment removed 87-95% of the total concentrations of APIs detected. In Kappala, GAC removed 20 and ozonation (7 g O-3/m(3)) 21 of 24 APIs detected in regular effluent. In Uppsala, GAC removed 25 and ozonation (5.4 g O-3/m(3)) 15 of 25 APIs detected in effluent. GAC and ozonation also reduced biomarker responses caused by unidentified pollutants in STP effluent water. Elevated ethoxyresorufin-O-deethylase (EROD) activity in gills was observed in fish exposed to effluent in both STPs. Gene expression analysis carried out in Kappala showed increased concentrations of cytochrome P450 (CYP1A5 and CYP1C3) transcripts in gills and of CYP1As in liver of fish exposed to effluent. In fish exposed to GAC- or ozone-treated effluent water, gill EROD activity and expression of CYP1As and CYP1C3 in gills and liver were generally equal to or below levels in fish held in tap water. The joint application of chemical analysis and sensitive biomarkers proved useful for evaluating contaminant removal in STPs with new technologies.
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| 25. |
- Betsholtz, Alexander, et al.
(författare)
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Tracking 14C-labeled organic micropollutants to differentiate between adsorption and degradation in GAC and biofilm processes
- 2021
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Ingår i: Environmental Science and Technology. - : The American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:16, s. 11318-11327
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Tidskriftsartikel (refereegranskat)abstract
- Granular activated carbon (GAC) filters can be used to reduce emissions of organic micropollutants via municipal wastewater, but it is still uncertain to which extent biological degradation contributes to their removal in GAC filters. 14C-labeled organic micropollutants were therefore used to distinguish degradation from adsorption in a GAC-filter media with associated biofilm. The rates and extents of biological degradation and adsorption were investigated and compared with other biofilm systems, including a moving bed biofilm reactor (MBBR) and a sand filter, by monitoring 14C activities in the liquid and gas phases. The microbial cleavage of ibuprofen, naproxen, diclofenac, and mecoprop was confirmed for all biofilms, based on the formation of 14CO2, whereas the degradation of 14C-labeled moieties of sulfamethoxazole and carbamazepine was undetected. Higher degradation rates for diclofenac were observed for the GAC-filter media than for the other biofilms. Degradation of previously adsorbed diclofenac onto GAC could be confirmed by the anaerobic adsorption and subsequent aerobic degradation by the GAC-bound biofilm. This study demonstrates the potential use of 14C-labeled micropollutants to study interactions and determine the relative contributions of adsorption and degradation in GAC-based treatment systems.
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