| 1. |
- Wu, Xue, 1986, et al.
(author)
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Ammonium recovery from reject water combined with hydrogen production in a bioelectrochemical reactor
- 2013
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In: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 146, s. 530-536
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Journal article (peer-reviewed)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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| 2. |
- Mårtensson, Lennart, 1957-, et al.
(author)
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Biomass from wetlands and other valuable conservation areas as substrate for industrial biotechnology
- 2016
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In: 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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Conference paper (peer-reviewed)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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| 3. |
- Soam, Shveta, 1987-, et al.
(author)
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Life cycle assessment of rice straw utilization practices in India
- 2017
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In: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 228, s. 89-98
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Journal article (peer-reviewed)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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| 4. |
- Modin, Oskar, 1980
(author)
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A mathematical model of aerobic methane oxidation coupled to denitrification
- 2018
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In: Environmental Technology (United Kingdom). - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 39:9, s. 1217-1225
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Journal article (peer-reviewed)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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| 5. |
- Modin, Oskar, 1980, et al.
(author)
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Hill-based dissimilarity indices and null models for analysis of microbial community assembly
- 2020
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In: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 8:1
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Journal article (peer-reviewed)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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| 6. |
- Modin, Oskar, 1980, et al.
(author)
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Three promising applications of microbial electrochemistry for the water sector
- 2017
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In: Environmental Science: Water Research and Technology. - : Royal Society of Chemistry (RSC). - 2053-1419 .- 2053-1400. ; 3:3, s. 391-402
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Journal article (peer-reviewed)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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| 7. |
- Rämö, Robert, et al.
(author)
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Sediment Remediation Using Activated Carbon: Effects of Sorbent Particle Size and Resuspension on Sequestration of Metals and Organic Contaminants.
- 2022
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In: Environmental toxicology and chemistry. - : Wiley. - 1552-8618 .- 0730-7268. ; 41:4, s. 1096-1110
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Journal article (peer-reviewed)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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| 8. |
- Timmusk, Salme, et al.
(author)
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Sfp-type PPTase inactivation promotes bacterial biofilm formation and ability to enhance wheat drought tolerance
- 2015
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In: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 6
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Journal article (peer-reviewed)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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| 9. |
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| 10. |
- Wadström, Christoffer, et al.
(author)
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Exploring total economic values in an emerging urban circular wastewater system
- 2023
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In: Water Research. - : Elsevier BV. - 1879-2448 .- 0043-1354. ; 233
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Research review (peer-reviewed)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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