| 1. |
- Rämö, Robert, et al.
(författare)
-
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.
|
|
| 2. |
- Eivazihollagh, Alireza, et al.
(författare)
-
On chelating surfactants : Molecular perspectives and application prospects
- 2019
-
Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322 .- 1873-3166. ; 278, s. 688-705
-
Tidskriftsartikel (refereegranskat)abstract
- Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.
|
|
| 3. |
- Åkesson, Sofia, et al.
(författare)
-
Characterizing natural degradation of tetrachloroethene (PCE) using a multidisciplinary approach
- 2020
-
Ingår i: Ambio: a Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 50, s. 1074-1088
-
Tidskriftsartikel (refereegranskat)abstract
- A site in mid-western Sweden contaminated with chlorinated solvents originating from a previous dry cleaning facility, was investigated using conventional groundwater analysis combined with compound-specific isotope data of carbon, microbial DNA analysis, and geoelectrical tomography techniques. We show the value of this multidisciplinary approach, as the different results supported each interpretation, and show where natural degradation occurs at the site. The zone where natural degradation occurred was identified in the transition between two geological units, where the change in hydraulic conductivity may have facilitated biofilm formation and microbial activity. This observation was confirmed by all methods and the examination of the impact of geological conditions on the biotransformation process was facilitated by the unique combination of the applied methods. There is thus significant benefit from deploying an extended array of methods for these investigations, with the potential to reduce costs involved in remediation of contaminated sediment and groundwater.
|
|
| 4. |
- Sandhi, Arifin, 1986-, et al.
(författare)
-
Phytofiltration of arsenic by aquatic moss (Warnstorfia fluitans)
- 2017
-
Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424.
-
Tidskriftsartikel (refereegranskat)abstract
- This work investigates whether aquatic moss (Warnstorfia fluitans) originating from an arsenic (As)-contaminated wetland close to a mine tailings impoundment may be used for phytofiltration of As. The aim was to elucidate the capacity of W. fluitans to remove As from arsenite and arsenate contaminated water, how nutrients affect the As uptake and the proportion of As adsorption and absorption by the moss plant, which consists of dead and living parts.Arsenic removal from 0, 1, or 10% Hoagland nutrient solution containing 0–100 μM arsenate was followed over 192 h, and the total As in aquatic moss after treatment was analysed. The uptake and speciation of As in moss cultivated in water containing 10 μM arsenate or arsenite were examined as As uptake in living (absorption + adsorption) and dead (adsorption) plant parts.Results indicated that W. fluitans removed up to 82% of As from the water within one hour when 1 μM arsenate was added in the absence of nutrients. The removal time increased with greater nutrient and As concentrations. Up to 100 μM As had no toxic effect on the plant biomass. Both arsenite and arsenate were removed from the solution to similar extents and, independent of the As species added, more arsenate than arsenite was found in the plant. Of the As taken up, over 90% was firmly bound to the tissue, a possible mechanism for resisting high As concentrations. Arsenic was both absorbed and adsorbed by the moss, and twice as much As was found in living parts as in dead moss tissue. This study revealed that W. fluitans has potential to serve as a phytofilter for removing As from As-contaminated water without displaying any toxic effects of the metalloid.
|
|
| 5. |
- Önneby, Karin
(författare)
-
Bioaugmentation for reduction of diffuse pesticide contamination : a bioprophylactic concept
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pesticides and their residues frequently contaminate surface waters and groundwater so consequently there is a great need to identify methods and practices that reduce such contamination. This thesis examined the potential of a 'bioprophylactic' concept based on the hypothesis that diffuse contamination after application in the field can be significantly reduced if pesticides are degraded as rapidly as possible after the intended effect has been achieved. This involves adding pesticide degraders together with the pesticide at the time of application. Such enhanced degradation is particularly important for pesticides used on non-agricultural soils with low degradation and high leaching potential (e.g. roadsides, railway embankments, paths, farmyards, urban land). The herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) was used as a model herbicide in this thesis, together with its degrader Sphingobium sp. T51. Soil inoculation with Sphingobium sp. T51 in microcosms significantly enhanced the degradation of MCPA compared with an uninoculated soil, without losing the herbicidal effect. In sand, 105 cells g-1 dry weight of soil reduced the MCPA concentration by 79-86% within one day, while only 0-31% reduction was observed in the uninoculated control after three days. However, Sphingobium sp. T51 needs to be formulated to retain its viability and degradation activity during prolonged storage and also for protection from the harsh environmental stresses associated with its application and functioning in the field. Both freeze drying and fluidised bed drying of Sphingobium sp. T51 resulted in high initial cell survival rates, of 67-85%. The storage stability of formulated Sphingobium sp. T51 was dependent on the formulation excipient/carrier used, storage temperature and atmospheric conditions. Sphingobium sp. T51 demonstrated approximately 50% survival in a freeze-dried sucrose formulation after six months of storage under partial vacuum at 25 °C. A fluidised bed-dried formulation with cottonseed flour as carrier resulted in the highest MCPA degradation in microcosms, but the storage stability was insufficient. Formulated and long-term stored Sphingobium sp. T51 reduced pesticide leaching by 85-94% of the total amount added in sand columns. Future research needs regarding practical implementation of the concept are discussed.
|
|
| 6. |
- Santos, Graziely Cristina, 1983-, et al.
(författare)
-
Comparative Analysis of Azo Dye Biodegradation by Aspergillus oryzae and Phanerochaete chrysosporium
- 2014
-
Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 225:7
-
Tidskriftsartikel (refereegranskat)abstract
- The textile industry often releases effluents into the environment without proper treatment or complete dye removal. Azo dyes, which are characterized by azo groups (―N═N―), are frequently used in the textile industry. Among the different wastewater treatment methods available, biological treatment has been extensively studied. The aim of the present study was to compare the biodegradation of the azo dye Direct Blue 71 by the fungi Phanerochaete chrysosporium and Aspergillus oryzae in paramorphogenic form using a 100 μg/ml dye solution. Biodegradation tests were performed within 240 h. The absorbance values obtained with UV-VIS spectrophotometry were used to determine the absorbance ratio and the percentage of dye discoloration following the biodegradation test. FTIR analysis allowed the identification of molecular compounds in the solution before and after biodegradation. Both A. oryzae and P. chrysosporium demonstrated considerable potential regarding the biodegradation of dyes in wastewater. These results may contribute toward improving effluent treatment systems in the textile industry.
|
|
| 7. |
- Anbalagan, Anbarasan, 1988-
(författare)
-
A passage to wastewater nutrient recovery units : Microalgal-Bacterial bioreactors
- 2018
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, the microalgal–bacterial process has been considered to be a very attractive engineering solution for wastewater treatment. However, it has not been widely studied in the context of conventional wastewater treatment design under Swedish conditions. The technology holds several advantages: as a CO2 sink, ability to withstand cold conditions, ability to grow under low light, fast settling without chemical precipitation, and reducing the loss of valuable nutrients (CO2, N2, N2O, PO4). The process also provides the option to be operated either as mainstream (treatment of municipal wastewater) or side stream (treatment of centrate from anaerobic digesters) to reduce the nutrient load of the wastewater. Furthermore, the application is not only limited to wastewater treatment; the biomass can be used to synthesise platform chemicals or biofuels and can be followed by recovery of ammonium and phosphate for use in agriculture.In the present study, the feasibility of applying the process in Swedish temperature and light conditions was investigated by implementing microalgae within the activated sludge process. In this context, the supporting operational and performance indicators (hydraulic retention time (HRT), sludge retention time (SRT) and nutrients removal) were evaluated to support naturally occurring consortia in photo-sequencing and continuous bioreactor configuration. Furthermore, CO2 uptake and light spectrum-mediated nutrient removal were investigated to reduce the impact on climate and the technical challenges associated with this type of system.The results identified effective retention times of 6 and 4 days (HRT = SRT) under limited lighting to reduce the electrical consumption. From the perspective of nitrogen removal, the process demands effective CO2 input either in the mainstream or side stream treatment. The incorporation of a vertical absorption column demonstrated effective CO2 mass transfer to support efficient nitrogen and phosphorus removal as a side stream treatment. However, the investigation of a continuous single-stage process as the mainstream showed a requirement for a lower SRT in comparison to semi-continuous operation due to faster settlability, regardless of inorganic carbon. Furthermore, the process showed an effective reduction of influent phosphorus and organic compounds (i.e. COD/TOC) load in the wastewater as a result of photosynthetic aeration. Most importantly, the operation was stable at the temperature equivalent of wastewater (12 and 13 ˚C), under different lighting (white, and red-blue wavelengths) and retention times (6 and 1.5 d HRT) with complete nitrification. Additionally, the biomass production was stable with faster settling properties without any physiochemical separation.The outcomes of this thesis on microalgal–bacterial nutrient removal demonstrates that (1) photosynthesis-based aeration at existing wastewater conditions under photo-sequential and continuous photobioreactor setup, (2) flocs with rapid settling characteristics at all studied retention times, (3) the possibility of increasing carbon supplementation to achieve higher carbon to nitrogen balance in the photobioreactor, and (4) most importantly, nitrification-based microalgal biomass uptake occurred at all spectral distributions, lower photosynthetic active radiation and existing wastewater conditions.
|
|
| 8. |
- Bonaglia, Stefano, et al.
(författare)
-
Capping with activated carbon reduces nutrient fluxes, denitrification and meiofauna in contaminated sediments
- 2019
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 148, s. 515-525
-
Tidskriftsartikel (refereegranskat)abstract
- Sediment capping with activated carbon (AC) is an effective technique used in remediation of contaminated sediments, but the ecological effects on benthic microbial activity and meiofauna communities have been largely neglected. This study presents results from a 4-week experiment investigating the influence of two powdered AC materials (bituminous coal-based and coconut shell-derived) and one control material (clay) on biogeochemical processes and meiofauna in contaminated sediments. Capping with AC induced a 62‒63% decrease in denitrification and a 66‒87 % decrease in dissimilatory nitrate reduction to ammonium (DNRA). Sediment porewater pH increased from 7.1 to 9.0 and 9.7 after addition of bituminous AC and biomass-derived AC, respectively. High pH (>8) persisted for at least two weeks in the bituminous AC and for at least 24 days in the coconut based AC, while capping with clay had no effect on pH. We observed a strong impact (nitrate fluxes being halved in presence of AC) on nitrification activity as nitrifiers are sensitive to high pH. This partly explains the significant decrease in nitrate reduction rates since denitrification was almost entirely coupled to nitrification. Total benthic metabolism estimated by sediment oxygen uptake was reduced by 30 and 43 % in presence of bituminous coal-based AC and coconut shell-derived AC, respectively. Meiofauna abundances decreased by 60‒62 % in the AC treatments. Taken together, these observations suggest that AC amendments deplete natural organic carbon, intended as food, to heterotrophic benthic communities. Phosphate efflux was 91 % lower in presence of bituminous AC compared to untreated sediment probably due to its content of aluminum (Al) oxides, which have high affinity for phosphate. This study demonstrates that capping with powdered AC produces significant effects on benthic biogeochemical fluxes, microbial processes and meiofauna abundances, which are likely due to an increase in porewater pH and to the sequestration of natural, sedimentary organic matter by AC particles.
|
|
| 9. |
- Gentili, Francesco, et al.
(författare)
-
Algal cultivation in urban wastewater : an efficient way to reduce pharmaceutical pollutants
- 2017
-
Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176. ; 29:1, s. 255-262
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate whether pharmaceutical pollutants in urban wastewater can be reduced during algal cultivation. A mixed population of wild freshwater green algal species was grown on urban wastewater influent in a 650 L photobioreactor under natural light and with the addition of flue gases. Removal efficiencies were very high (> 90 %), moderate (50-90 %), low (10-50 %), and very low or non-quantifiable (< 10 %) for 9, 14, 11, and 18 pharmaceuticals, respectively, over a 7-day period. High reduction was found in the following pharmaceuticals: the beta-blockers atenolol, bispropol, and metoprolol; the antibiotic clarithromycine; the antidepressant bupropion; the muscle relaxant atracurium; hypertension drugs diltiazem and terbutaline used to relive the symptoms of asthma. Regression analysis did not detect any relationship between the reduction in pharmaceutical contents and light intensity reaching the water surface of the algal culture. However, the reduction was positively correlated with light intensity inside the culture and stronger when data collected during the night were excluded. Algae cultivation can remove partially or totally pharmaceutical pollutants from urban wastewater, and this opens up new possibilities for treating urban wastewater.
|
|
| 10. |
- Pondja, Estevao
(författare)
-
Environmental aspects of coal mine drainage: a regional study of Moatize in Mozambique
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mozambique is one of the largest coal producers in Africa. Extraction of the coal is carried out in the Moatize district of the Tete province in the center of the country. A surface mining technique is used to extract the coal below ground level. During mining activities, sulfide minerals, which are commonly associated with coal, are exposed to oxygen and water, leading to the generation of acid mine drainage (AMD). AMD is high in acidity and has a high content of metals, metalloids and sulfate that can cause severe damage to the environment. Moatize is inside the lower Zambezi River basin, the pollution that occurs there due to mining activities constituting a risk both for public health and for the water resources. The standard guidelines in Mozambique for wastewater from coal mining are very weak, allowing the coal mining companies to pollute considerably. The prevention, containment and remediation of polluted mine water are measures that should be carried out to avoid the spread of pollution. Prevention is the least expensive strategy, but it cannot always prevent the generation of polluted mine water. Thus containment and treatment need to be put into practice. Both active and passive treatment are used to treat polluted mine water. Since Moatize is a largely unstudied area, both static and leaching tests were carried out to investigate the possibility of AMD being generated. The geochemical processes that could impact on the quality of mine drainage stemming from the waste rock there were assessed. Use of cost-effective methods for the treatment of mine water by use of bioremediation coupled with adsorption, using cassava peels that are readily available in the country as a carbon source and as an adsorbent is proposed. Since climate changes and climate variability can exacerbate the negative impact of surface mining, the possibility of this was assessed. It was found that the production of AMD was likely in at least one of the coal mines in Moatize. The mine water from coal mines in Moatize was found to have a high content of sulfate, calcium, magnesium and manganese. A set of guidelines for coal mine effluents that was developed, based on different guidelines obtained from around the world, was proposed for Mozambique. Sulfate reducing bacteria coupled with adsorption appeared to be appropriate for removing these pollutants. Cassava peels used as adsorbents appeared to be effective in removing calcium, magnesium and manganese. Based on climate data, the period from November on through February was found to be the period in which the pollution load in Moatize was greatest. Since the flow rate in the Revúbué River, which is close to the coal mines, is highly dependent upon the precipitation that occurs during the rainy season, the discharge of polluted mine water should be avoided. To achieve sustainable mining in Moatize, the coal mining companies, the regulators and the stakeholders from water sector there need to work together. A framework for integrating efforts to satisfy the needs of the different stakeholders involved in the water sector in Moatize was proposed.
|
|
| 11. |
- Xafenias, Nikolaos, 1981, et al.
(författare)
-
Evaluating hexavalent chromium reduction and electricity production in microbial fuel cells with alkaline cathodes
- 2015
-
Ingår i: International Journal of Environmental Science and Technology. - : Springer Science and Business Media LLC. - 1735-1472 .- 1735-2630. ; 12:8, s. 2435-2446
-
Tidskriftsartikel (refereegranskat)abstract
- The work investigated the efficiency of microbial fuel cells (MFCs) for the treatment of alkaline hexavalent chromium containing wastewater. When lactate was used as the metal chelator in alkaline (pH 8) abiotic cathodes, hexavalent chromium concentration dropped from 10 mg l-1 to undetectable levels within the first 45 h of operation. Power density produced in the pH 8 abiotic cathodes was up to 21.4 mW m-2, and in the pH 9 cathodes up to 2.4 mW m-2; these values were well comparable with other values found in the literature for biologically catalysed cathodes, even at lower pH values. When Shewanella oneidensis MR-1 was present in a hexavalent chromium reducing cathode at pH 8, current production contributed by 26 % to the total hexavalent chromium reduced during the 36 days of operation. On the other hand, when hexavalent chromium (10 mg l-1) was controllably added in the anode where S. oneidensis MR-1 was present, up to 73 % of current decreased immediately after every hexavalent chromium addition; this toxic effect remained even after hexavalent chromium was depleted in the anode and strongly indicates that the presence of hexavalent chromium in the anodes of MFCs must be avoided. Overall, our results indicate that alkaline hexavalent chromium wastewater can be effectively remediated in the cathodes of MFCs, provided that a metal chelator is present in the cathodes and that hexavalent chromium is not present in the anodes.
|
|
| 12. |
|
|
| 13. |
- Dalahmeh, Sahar
(författare)
-
Bark and charcoal filters for greywater treatment : pollutant removal and recycling opportunities
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Water scarcity, inappropriate sanitation and wastewater pollution are critically important global issues. Greywater is a sustainable water source for recycling, so this thesis examined simple, robust, low-cost alternatives for on-site treatment of greywater to irrigation water quality. Laboratory-scale pine bark, activated charcoal and sand filters were evaluated as regards their pollutant removal and interactions between medium properties, greywater, microbial activity and bacterial community structure. The effects of hydraulic and organic loading rates (HLR and OLR) were described by general regression models (GRM). The quality of the treated greywater was evaluated against Jordanian standards for irrigation water. A series of experiments examined treatment of artificial greywater in terms of lowering biochemical oxygen demand (BOD5), chemical oxygen demand (COD), phosphorus (Tot-P), nitrogen (Tot-N) and pathogen indicators (total thermotolerant coliforms) and tracer microorganisms (enterohaemorrhagic Escherichia coli (EHEC) and bacteriophage PhiX). Following greywater loading, all filter materials developed biofilms with high bacterial diversity and richness. The driving force shaping bacterial communities in bark material was its organic composition and low pH, while the communities in the charcoal and sand filters were more influenced by the greywater. The GRM indicated that the performance of all filters was influenced by the HLR and OLR of the present and previous runs. The organic matter content and surface and hydraulic properties of the bark filters resulted in high BOD5 removal rates (94-99%), even at increased HLR and OLR, but accompanied by release of dissolved organic substances originating from the bark itself. High nitrification occurred in the bark filters in all loading regimes tested, but with low Tot-N removal. The bark filters demonstrated 1-3 log10 removal of microorganisms, but bark organic nature made its filters more vulnerable to biodegradation and disintegration. The charcoal had large specific surface area, which provided the capacity for intermediate-high removal of BOD5 (83-97%), Tot-N (50-98%) and Tot-P (64-98%), but removal of microorganisms was poor. The sand filters demonstrated low BOD5 removal (67-91%) and high nitrification, but low nitrogen removal. Greywater treatment by bark and charcoal filters reduced their organics content to acceptable irrigation levels. Nitrogen and microorganisms must be further reduced to meet Jordanian standards on treated wastewater for irrigation.
|
|
| 14. |
- Knutsson, Pavleta, 1980, et al.
(författare)
-
Phycoremediation of heavy metals in ashes
- 2014
-
Ingår i: Chalmers Life Science Area of Advance Meeting, May 5, Göteborg.
-
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.
|
|
| 15. |
- Laohaprapanon, Sawanya, et al.
(författare)
-
Anaerobic baffled reactor coupled with chemical precipitation for treatment and toxicity reduction of industrial wastewater
- 2014
-
Ingår i: Environmental technology. - : Informa UK Limited. - 0959-3330 .- 1479-487X. ; 35:2, s. 154-162
-
Tidskriftsartikel (refereegranskat)abstract
- This study describes the reduction of soluble chemical oxygen demand (CODs) and the removal of dissolved organic carbon (DOC), formaldehyde (FA) and nitrogen from highly polluted wastewater generated during cleaning procedures in wood floor manufacturing using a laboratory-scale biological anaerobic baffled reactor followed by chemical precipitation using MgCl2·6H2O+Na2HPO4. By increasing the hydraulic retention time from 2.5 to 3.7 and 5 days, the reduction rates of FA, DOC and CODs of nearly 100%, 90% and 83%, respectively, were achieved. When the Mg:N:P molar ratio in the chemical treatment was changed from 1:1:1 to 1.3:1:1.3 at pH 8, the NH4+ removal rate increased from 80% to 98%. Biologically and chemically treated wastewater had no toxic effects on Vibrio fischeri and Artemia salina whereas chemically treated wastewater inhibited germination of Lactuca sativa owing to a high salt content. Regardless of the high conductivity of the treated wastewater, combined biological and chemical treatment was found to be effective for the removal of the organic load and nitrogen, and to be simple to operate and to maintain. A combined process such as that investigated could be useful for on-site treatment of low volumes of highly polluted wastewater generated by the wood floor and wood furniture industries, for which there is no suitable on-site treatment option available today.
|
|
| 16. |
- Sandhi, Arifin, et al.
(författare)
-
Moss based constructed wetland system : is it possible to use aquatic moss (warnstorfia fluitans) for removal of as in an eco-friendly approach?
- 2018
-
Ingår i: Book of Abstracts. - Kalmar, Växjö : Linnaeus university. - 9789188898289 ; , s. 17-
-
Konferensbidrag (refereegranskat)abstract
- The heavy metal and metalloid contaminated groundwater is considered as one of the major global environmental disasters that need sustainable solutions. One sustainable environment-friendly solution is using plant-based remediation, or phytoremediation. For contaminated water aquatic plant based phytofiltration could be applied. A Swedish aquatic moss species (Warnstorfia fluitans) have been discovered to accumulate high levels of As (arsenic) from the water. In a number of areas in Sweden, the As content in the groundwater is high due to mining activities and geochemical conditions. Our hypothesis was that since this moss species could accumulate As from contaminated water it would be possible to apply in constructed wetland system for removal of As from water. The aim of this study was to investigate the removal of As from the outlet water by using W. fluitans in constructed mesocosm type wetland systems with various water flow speeds under greenhouse conditions. Besides these, As content in the vegetables (lettuce, Latuca sativa) grown in this outlet water was also analysed. The total As concentration was analysed with hydride generated atomic absorption spectrophotometry (HG-AAS). Results showed that W. fluitans could reduce the As concentration in the water with 36 and 56% from initial As concentration at high (5 mL/min) and low (1.5 mL/min) water flow rate, respectively. The As concentration in the vegetables was also lower when low flow outlet has been applied as irrigation water. In conclusion, the result fits our hypothesis that aquatic moss could be used in the constructed wetland system to reduce As content in irrigation water and by that also in the irrigated vegetables.
|
|
| 17. |
|
|
| 18. |
- Li, Haichao
(författare)
-
Relationships between different types of biochar and N2O emissions during composting based on roles of nosZ-carrying denitrifying bacterial communities enriched on compost and biochar particles
- 2024
-
Ingår i: Bioresource Technology. - 0960-8524 .- 1873-2976. ; 394
-
Tidskriftsartikel (refereegranskat)abstract
- Biochar has demonstrated the potential in mitigating N2O emissions during composting. However, little is known about how microbial communities on biochar particles interact with N2O emissions. This study selected three types of biochar (corn stalk biochar (CSB), rape straw biochar (RSB), and bamboo charcoal (BC)) to investigate the relationship between N2O emissions and denitrifying bacterial communities on compost and biochar particles. The results showed that N2O emissions rate were higher in the thermophilic phase, and the average emissions rate of BC treatment were lower 40% and 26% than CSB and RSB, respectively. The nosZ-carrying denitrifying bacterial community played a key role in reducing N2O emissions, and the network indicated that Rhizobium and Paracoccus on compost particles may have played major roles in reducing N2O emissions, but only Paracoccus on biochar particles. Notably, BC enhanced the efficiency of N2O emission reduction by enhancing the abundance of these key genera.
|
|
| 19. |
- Peters, Gregory, 1970, et al.
(författare)
-
Improving odour assessment in LCA - the odour footprint
- 2014
-
Ingår i: International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 1614-7502 .- 0948-3349. ; 19:11, s. 1891-1900
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose Odour is an important aspect of systems for humanand agricultural waste management and many technologiesare developed with the sole purpose of reducing odour.Compared with greenhouse gas assessment and the assessmentof toxicity, odour assessment has received little attentionin the life cycle assessment (LCA) community. This articleaims to redress this.Methods Firstly, a framework for the assessment of odourimpacts in LCA was developed considering the classicalLCA framework of emissions, midpoint and endpoint indicators.This suggested that an odour footprint midpoint indicatorwas worth striving for. An approach to calculating an arealindicator we call “odour footprint”, which considers the odourdetection threshold, the diffusion rate and the kinetics ofdegradation of odourants, was implemented in MATLAB.We demonstrated the use of the characterisation factors wecalculated in a case study based on odour removal technologyapplied to a pig barn.Results and discussion We produced a list of 33 linear characterisation factors based on hydrogen sulphide equivalents, analogous to the linear carbon dioxide equivalency factors in use in carbon footprinting, or the dichlorobenzene equivalency factors developed for assessment of toxic impacts in LCA. Like the latter, this odour footprint method does not take local populations and exposure pathway analysis into account—its intent is not to assess regulatory compliance or detailed design. The case study showed that despite the need for materials and energy, large factor reductions in odour footprint andeutrophication potential were achieved at the cost of a smaller factor increase in greenhouse emissions.Conclusions The odour footprint method is proposed as animprovement on the established midpoint method for odourassessment in LCA. Unlike it, the method presented hereconsiders the persistence of odourants. Over time, we hopeto increase the number of characterised odourants, enablinganalysts to perform simple site-generic LCA on systems withodourant emissions.
|
|
| 20. |
- Azzi, Elias Sebastian, et al.
(författare)
-
Prospective Life Cycle Assessment of Large-Scale Biochar Production and Use for Negative Emissions in Stockholm
- 2019
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 53:14, s. 8466-8476
-
Tidskriftsartikel (refereegranskat)abstract
- Several cities in Sweden are aiming for climate neutrality within a few decades and for negative emissions thereafter. Combined biochar, heat, and power production is an option to achieve carbon sequestration for cities relying on biomass-fuelled district heating, while biochar use could mitigate environmental pollution and greenhouse gas emissions from the agricultural sector. By using prospective life cycle assessment, the climate impact of the pyrolysis of woodchips in Stockholm is compared with two reference scenarios based on woodchip combustion. The pyrolysis of woodchips produces heat and power for the city of Stockholm, and biochar whose potential use as a feed and manure additive on Swedish dairy farms is explored. The climate change mitigation trade-off between bioenergy production and biochar carbon sequestration in Stockholm's context is dominated by the fate of marginal power. If decarbonisation of power is achieved, building a new pyrolysis plant becomes a better climate option than conventional combustion. Effects of cascading biochar use in animal husbandry are uncertain but could provide 10-20% more mitigation than direct biochar soil incorporation. These results help design regional biochar systems that combine negative carbon dioxide emissions with increased methane and nitrous oxide mitigation efforts and can also guide the development of minimum performance criteria for biochar products.
|
|
| 21. |
- Ciuk Karlsson, Susanna
(författare)
-
Simulating water and pollutant transport in bark, charcoal and sand filters for greywater treatment
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A septic tank combined with a sand filter is the most common onsite wastewater treatment system worldwide, since it is a simple, lowcost and reliable treatment method. Alternatives to sand in filters could be advantageous in terms of availability of material and enhanced treatment properties. In this study, flow dynamics and pollutant transport in three filter materials; sand, pine bark and activated charcoal, intermittently dosed with artificial greywater, were simulated using the HYDRUS wetland module. The simulated results were compared with observations from laboratory filters and model hydraulic and microbial parameters were calibrated. Emphasis was placed on simulating the removal of organic pollutants by each filter type. Furthermore, for the bark and charcoal filters, removal of organic matter was simulated for different hydraulic and organic loading rates (HLR = 32 and 64 l m⁻² day⁻¹ and OLR = 13-6 and 28 g BOD₅ m⁻² day⁻¹). Comparing simulated with measured cumulated effluent volume, the normalised root mean square error for all three filter materials was small (0.7-3.5%). The simulated bark filter COD removal in different loading regimes (HLR = 32 and 64 l m⁻² day⁻¹, OLR = 13-16 and 28 g BOD₅ m⁻² day⁻¹) was overestimated by 13-20 percentage points compared with the measured values. When release of organic matter from the bark material itself was accounted for, the difference was reduced to 2-10 percentage points. Simulation of the charcoal filter demonstrated 94 and 91 % removal of COD for HLR = 32 and OLR = 13 - 16 g BOD₅ m⁻² day⁻¹, which compared well with the measured values, 95 ± 2 % and 89 ± 11 %, respectively. However, simulated COD removal for Run 2 (70%) and Run 5 (72%) was low compared with the measured values (90 ± 7 and 84 ± 4 %). The measured sand filter effluent concentration of COD was 245 mg l⁻¹ and the simulated effluent concentration of COD was 134 mg l⁻¹ for HLR = 32 and OLR = 14 g BOD₅ m⁻² day⁻¹. After including an effect of water flow along the column wall in the model, the simulated effluent concentration of COD was 337 mg l⁻¹. These simulations of bark, charcoal and sand filters improved understanding of filter functions and identified possible filter design developments.
|
|
| 22. |
- Das, Sarbashis, et al.
(författare)
-
Characterization of three Mycobacterium spp. with potential use in bioremediation by genome sequencing and comparative genomics
- 2015
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 7:7, s. 1871-1886
-
Tidskriftsartikel (refereegranskat)abstract
- We provide the genome sequences of the type strains of the polychlorophenol-degrading Mycobacterium chlorophenolicum (DSM43826), the degrader of chlorinated aliphatics Mycobacterium chubuense (DSM44219) and Mycobacterium obuense (DSM44075) that has been tested for use in cancer immunotherapy. The genome sizes of M. chlorophenolicum, M. chubuense and M. obuense are 6.93, 5.95 and 5.58 Mbps with GC-contents of 68.4, 69.2 and 67.9%, respectively. Comparative genomic analysis revealed that 3254 genes are common and we predicted approximately 250 genes acquired through horizontal gene transfer from different sources including proteobacteria. The data also showed that the biodegrading Mycobacterium spp. NBB4, also referred to as M. chubuense NBB4, is distantly related to the M. chubuense type strain and should be considered as a separate species, we suggest it to be named M. ethylenense NBB4. Among different categories we identified genes with potential roles in: biodegradation of aromatic compounds, and copper homeostasis. These are the first non-pathogenic Mycobacterium spp. found harboring genes involved in copper homeostasis. These findings would therefore provide insight into the role of this group of Mycobacterium spp. in bioremediation as well as the evolution of copper homeostasis within the Mycobacterium genus.
|
|
| 23. |
- de Jonge, Nadieh, et al.
(författare)
-
Characterisation of microbial communities for improved management of anaerobic digestion of food waste
- 2020
-
Ingår i: Waste Management: international journal of integrated waste management, science and technology. - : Elsevier BV. - 0956-053X. ; 117, s. 124-135
-
Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestion of food waste is an attractive and increasingly popular technology within waste management and energy recovery. A better understanding of the microbiology associated with anaerobic digestion of food waste will provide new insight into the operational conditions required for optimizing this process, as well as its potential for utilisation in co-digestion systems. Eighteen full-scale reactors processing varying proportions of food waste under diverse operational configurations were subjected to microbial community analysis by amplicon sequencing of the 16S rRNA and mcrA genes to capture the bacterial and methanogenic populations. Statistical correlations between microbial populations, plant design and operating conditions revealed that the microbial communities were shaped by operational parameters such as the primary substrate type and operational temperature, while the methanogenic communities showed a more reactor specific distribution. The distribution of microbes based on the waste processed in the surveyed digesters was explored, as well as the presence of specialist populations such as syntrophs and methanogens. Food waste digester communities were not associated with a strong microbial fingerprint compared to other waste types (wastewater and manure) but contained greater abundance and unique syntrophic acetate oxidising populations, suggesting that co-digestion with food waste may improve the functional diversity of anaerobic digesters.
|
|
| 24. |
- Fernández-Calviño, David, et al.
(författare)
-
Using pine bark and mussel shell amendments to reclaim microbial functions in a Cu polluted acid mine soil
- 2018
-
Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 127, s. 102-111
-
Tidskriftsartikel (refereegranskat)abstract
- An extremely acid mine soil polluted with Cu was amended with pine bark, crushed mussel shell or a 1:1 mixture of these two by-products. The performance of the soil microbial community was measured as the bacterial and fungal community growth, which were monitored during 2 years following the amendments. Pine bark caused significant increases of microbial growth rates, but with distinct differences between fungal and bacterial groups. Bacterial growth increased transiently at intermediate rates of pine bark applications, but returned to control rates within 2 years of application. In contrast, pine bark applications consistently increased fungal growth with effects that were maintained throughout the study period. The addition of only crushed mussel shell to the mine soil caused very delayed positive effects on the bacterial growth and almost no significant effects on the fungal growth. However, the combination of pine bark with crushed mussel shells 1:1 mixtures caused positive growth responses of both bacteria and fungi that remained persistent throughout the 2 years of study. Fungal and bacterial growth were both suppressed in the mine soil by the lack of organic matter. In addition, bacterial growth was also secondarily suppressed by acidity, and hence, when organic matter (pine bark) additions were combined with pH increases (crushed mussel shell additions), bacterial growth was additionally stimulated. In conclusion, the proposed mixture of by-products (pine bark and crushed mussel shell) is suggested as a promising reclamation strategy for acid mine soils. These results also suggest that in soils like that studied here the organic matter limitation is a more important factor than the soil pH and Cu availability for fungal and bacterial performance.
|
|
| 25. |
- Figueroa, Daniela, 1980-, et al.
(författare)
-
Allochthonous Carbon-a Major Driver of Bacterioplankton Production in the Subarctic Northern Baltic Sea
- 2016
-
Ingår i: Microbial Ecology. - : Springer. - 0095-3628 .- 1432-184X. ; 71:4, s. 789-801
-
Tidskriftsartikel (refereegranskat)abstract
- Heterotrophic bacteria are, in many aquatic systems, reliant on autochthonous organic carbon as their energy source. One exception is low-productive humic lakes, where allochthonous dissolved organic matter (ADOM) is the major driver. We hypothesized that bacterial production (BP) is similarly regulated in subarctic estuaries that receive large amounts of riverine material. BP and potential explanatory factors were measured during May-August 2011 in the subarctic Råne Estuary, northern Sweden. The highest BP was observed in spring, concomitant with the spring river-flush and the lowest rates occurred during summer when primary production (PP) peaked. PLS correlations showed that ∼60 % of the BP variation was explained by different ADOM components, measured as humic substances, dissolved organic carbon (DOC) and coloured dissolved organic matter (CDOM). On average, BP was threefold higher than PP. The bioavailability of allochthonous dissolved organic carbon (ADOC) exhibited large spatial and temporal variation; however, the average value was low, ∼2 %. Bioassay analysis showed that BP in the near-shore area was potentially carbon limited early in the season, while BP at seaward stations was more commonly limited by nitrogen-phosphorus. Nevertheless, the bioassay indicated that ADOC could contribute significantly to the in situ BP, ∼60 %. We conclude that ADOM is a regulator of BP in the studied estuary. Thus, projected climate-induced increases in river discharge suggest that BP will increase in subarctic coastal areas during the coming century.
|
|
| 26. |
|
|
| 27. |
- Karan, Shivesh
(författare)
-
Potential for biochar carbon sequestration from crop residues: A global spatially explicit assessment
- 2023
-
Ingår i: GCB Bioenergy. - 1757-1693 .- 1757-1707. ; 15, s. 1424-1436
-
Tidskriftsartikel (refereegranskat)abstract
- Global warming necessitates urgent action to reduce carbon dioxide (CO2) emissions and remove CO2 from the atmosphere. Biochar, a type of carbonized biomass which can be produced from crop residues (CRs), offers a promising solution for carbon dioxide removal (CDR) when it is used to sequester photosynthetically fixed carbon that would otherwise have been returned to atmospheric CO2 through respiration or combustion. However, high-resolution spatially explicit maps of CR resources and their capacity for climate change mitigation through biochar production are currently lacking, with previous global studies relying on coarse (mostly country scale) aggregated statistics. By developing a comprehensive high spatial resolution global dataset of CR production, we show that, globally, CRs generate around 2.4 Pg C annually. If 100% of these residues were utilized, the maximum theoretical technical potential for biochar production from CRs amounts to 1.0 Pg C year(-1) (3.7 Pg CO(2)e year(-1)). The permanence of biochar differs across regions, with the fraction of initial carbon that remains after 100 years ranging from 60% in warm climates to nearly 100% in cryosols. Assuming that biochar is sequestered in soils close to point of production, approximately 0.72 Pg C year(-1) (2.6 Pg CO(2)e year(-1)) of the technical potential would remain sequestered after 100 years. However, when considering limitations on sustainable residue harvesting and competing livestock usage, the global biochar production potential decreases to 0.51 Pg C year(-1) (1.9 Pg CO(2)e year(-1)), with 0.36 Pg C year(-1) (1.3 Pg CO(2)e year(-1)) remaining sequestered after a century. Twelve countries have the technical potential to sequester over one fifth of their current emissions as biochar from CRs, with Bhutan (68%) and India (53%) having the largest ratios. The high-resolution maps of CR production and biochar sequestration potential provided here will provide valuable insights and support decision-making related to biochar production and investment in biochar production capacity.
|
|
| 28. |
- Mayers, Joshua, 1988, et al.
(författare)
-
Nutrients from anaerobic digestion effluents for cultivation of the microalga Nannochloropsis sp. - Impact on growth, biochemical composition and the potential for cost and environmental impact savings
- 2017
-
Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 26, s. 275-286
-
Tidskriftsartikel (refereegranskat)abstract
- Microalgal biotechnology has yielded a range of products for different consumer markets, but large scale production for bulk commodities is limited by the cost and environmental impact of production. Nutrient requirements for large-scale production contribute significantly to the cost and environmental impact of microalgal biomass production and should subsequently be addressed by more careful sourcing of nutrients. This study assessed the use of nitrogen and phosphorus contained in effluents from anaerobic digestion of food waste to cultivate the marine microalga Nannochloropsis sp. With suitable dilution, effluent could replace 100% of nitrogen demands and 16% of required phosphorus, without significant impacts on growth or biomass productivity. Additional phosphorus requirements could be decreased by increasing the N:P molar ratio of the media from 16:1 to 32:1. Nannochloropsis sp. accumulated lipid up to 50% of dry weight under N-stress, with significant increases in the content of saturated and mono-unsaturated fatty acids. Using empirical data generated in this study, the cost and environmental impact of nitrogen and phosphorus supply was assessed versus the use of fertilizers for biomass and biodiesel production. Nutrient requirements predicted by the Redfield Ratio overestimating impacts by as much as 140% compared to empirical data. By utilising residual nutrients and optimising nutrient supply, the cost and environmental impact of nitrogen and phosphorus were decreased by >90% versus the use of artificial fertilizers. This study demonstrates the importance of using empirical data for process evaluation and how anaerobic digestate effluent derived nutrients can contribute to the sustainability of algal biomass production.
|
|
| 29. |
- Mitter, Eduardo Kovalski, et al.
(författare)
-
Analysis of Acid Alizarin Violet N Dye Removal Using Sugarcane Bagasse as Adsorbent
- 2012
-
Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 223:2, s. 765-770
-
Tidskriftsartikel (refereegranskat)abstract
- With the development of the textile industry, there has been a demand for dye removal from contaminated effluents. In recent years, attention has been directed toward various natural solid materials that are capable of removing pollutants from contaminated water at low cost. One such material is sugarcane bagasse. The aim of the present study was to evaluate adsorption of the dye Acid Violet Alizarin N with different concentrations of sugarcane bagasse and granulometry in agitated systems at different pH. The most promising data (achieved with pH 2.5) was analyzed with both Freundlich and Langmuir isotherms equations. The model that better fits dye adsorption interaction into sugarcane bagasse is Freundlich equation, and thus the multilayer model. Moreover, a smaller bagasse granulometry led to greater dye adsorption. The best treatment was achieved with a granulometry value lower than 0.21 mm at pH 2.50, in which the total removal was estimated at a concentration of 16.25 mg mL−1. Hence, sugarcane bagasse proves to be very attractive for dye removal from textile effluents.
|
|
| 30. |
- Mohanty, Amar K., et al.
(författare)
-
Biocarbon materials
- 2024
-
Ingår i: Nature Reviews Methods Primers. - : Springer Nature. - 2662-8449. ; 4:1
-
Tidskriftsartikel (refereegranskat)
|
|
| 31. |
|
|
| 32. |
- Ni, Gaofeng
(författare)
-
When bioelectrochemical systems meet extremophiles, possibilities and challenges
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Extremophiles are microorganisms live and thrive in extreme environments that are harsh and hostile to most forms of life on earth (e.g. low pH, low temperature, high pH and high salinity). They have developed strategies to obtain nutrients and conserve energy to sustain life under these adverse conditions. Such metabolic capabilities are valuable to be exploit for industrial applications such as the remediation of environmental pollutions, which typically bring about extreme physicochemical conditions. The advancing technology bioelectrochemical systems can utilize the microbial metabolism to oxidize a substrate while simultaneously recover electrical energy or produce a useful product in an electrochemical set-up. It enables the remediation of pollutions, and its integration with extremophiles has opened up a wide range of possibilities to tackle various industrial waste streams with extreme conditions in an environmentally friendly manner. Inorganic sulfur compounds such as tetrathionate, thiocyanate and sulfide that originate from mining, metal refinery and petroleum industries are toxic and hazardous to the recipient water body and human health if discharged untreated. The remediation of these three compounds with bioelectrochemical systems that incorporates extremophiles was investigated in three separate studies of this thesis. 16S rRNA gene amplicon sequencing, metagenomics and metatranscriptomics are utilized to profile the microbial communities, and to understand their metabolic potential and states. Tetrathionate degradation with acidophilic microorganisms in microbial fuel cells at pH 2 was demonstrated in the first study of this thesis. Electricity was produced from the oxidation of tetrathionate, facilitated by the anodic microbiome. 16S rRNA gene amplicon sequencing showed that this community was dominated by members of the genera Thermoplasma, Ferroplasma, Leptospirillum, Sulfobacillus and Acidithiobacillus. Metagenomic analysis reconstructed genomes that were most similar to the genera Ferroplasma, Acidithiobacillus, Sulfobacillus and Cuniculiplasma. Together with metatranscriptomic analysis, it was indicated that this microbial community was metabolizing tetrathionate and other intermediate sulfur compounds via multiple pathways, the electrons released from oxidation were suggested to be transferred to the electrode via soluble electron shuttles. In addition, the Ferroplasma-like population in this study was suggested to be active in metabolising inorganic sulfur compounds and synthesizing soluble electron shuttles. Since characterized Ferroplasma species do not utilize inorganic sulfur compounds, the anodic compartment might have selected a novel Ferroplasma population. Next, thiocyanate degradation with psychrophilic microorganisms in microbial fuel cells at 8 °C was demonstrated for the first time. Electricity generation alongside with thiocyanate degradation facilitated by the anodic microbiome was observed. 16S rRNA gene amplicon sequencing and metatranscriptomics suggested that Thiobacillus was the predominant and most active population. mRNA analysis revealed that thiocyanate was metabolized primarily via the ‘cyanate’ degradation pathway; the resultant sulfide was oxidized; ammonium was assimilated; carbon dioxide was fixed as carbon source. It was also suggested by mRNA analysis that the consortium used multiple mechanisms to acclimate low temperature such as the synthesis of cold shock proteins, cold inducible proteins and molecular chaperones. Finally, sulfide removal with haloalkaliphilic microorganisms in microbial electrolysis cells operated at pH 8.8 to 9.5 and with 1.0 M sodium ion was investigated. The anodic microbiome was hypothesized to facilitate current generation by the oxidation of sulfide and of intermediate sulfur compounds to sulfate, which was supported by chemical analysis and microbial profiling. Dominant populations from the anode had 16S rRNA gene sequences that aligned within the genera Thioalkalivibrio, Thioalkalimicrobium, and Desulfurivibrio, which are known for sulfide oxidation. Intriguingly, Desulfurivibrio dominated the electrode-attached community, possibly enriched by the electrode as a selecting pressure. This finding suggested a novel role of this organism to carry out sulfide oxidation coupled to electron transfer to the electrode. These three studies demonstrated the possibilities of utilizing extremophilic bioelectrochemical systems to remediate various inorganic sulfur pollution streams. The advancing molecular microbiological tools facilitated the investigation towards the composition and metabolic state of the microbial community. Challenges remain in a more thorough understanding regarding the metabolism of extremophiles (e.g. sulfur metabolism and extracellular electron transfer) and better energy recovery in bioelectrochemical systems.
|
|
| 33. |
- Olofsson, Martin, et al.
(författare)
-
Baltic Sea microalgae transform cement flue gas into valuable biomass
- 2015
-
Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 11, s. 227-233
-
Tidskriftsartikel (refereegranskat)abstract
- We show high feasibility of using cement industrial flue gas as CO2 source for microalgal cultivation. The toxicity of cement flue gas (12-15% CO2) on algal biomass production and composition (lipids, proteins, carbohydrates) was tested using monocultures (Tetraselmis sp., green algae, Skeletonema marinoi, diatom) and natural brackish communities. The performance of a natural microalgal community dominated by spring diatoms was compared to a highly productive diatom monoculture S. marinoi fed with flue gas or air-CO2 mixture. Flue gas was not toxic to any of the microalgae tested. Instead we show high quality of microalgal biomass (lipids 20-30% DW, proteins 20-28% DW, carbohydrates 15-30% DW) and high production when cultivated with flue gas addition compared to CO2-air. Brackish Baltic Sea microalgal communities performed equally or better in terms of biomass quality and production than documented monocultures of diatom and green algae, often used in algal research and development. Hence, we conclude that microalgae should be included in biological solutions to transform waste into renewable resources in coastal waters. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
|
|
| 34. |
- Sandhi, Arifin, et al.
(författare)
-
Growing Salix spp. on heavy metal contaminated sediment (Oskarshamn, Sweden) as a joint phytoremediation and circular economy approach
- 2023
-
Ingår i: Environmental Advances. - : Elsevier. - 2666-7657. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- The sediments of rivers or harbours have always been considered sinks for numerous heavy metals, pesticides, chemicals and contaminants of anthropogenic origin. The eco-friendly management of contaminated sediment have received attention due to their large-scale presence in harbour areas. Application of bioenergy crop species, such as Salix spp., have shown a strong potential for reducing heavy metals from the contaminated sediment. The aim of this study was to investigate the application of Salix spp. on contaminated dredged sediment and heavy metal accumulation and translocation patterns in different parts of plants. Two Salix cultivars (Wilhelm and Ester; commercially available in Sweden) were cultivated in contaminated sediment for 5 weeks in a field setting. Heavy metals (Cd, Cu, Pb, Ni and Zn) content in different plant parts (root, cutting, shoot and leaves) were analysed by using atomic absorption spectrophotometer (AAS). The result indicated that the root biomass production was negatively affected for both cultivars due to the contaminated sediment medium, even though no morphological symptoms were present. Both Cd and Cu net accumulation were found to be significantly higher in Ester cultivars. The low translocation of heavy metals in Salix spp. hints that accumulated heavy metals are stored in the root parts. Low translocation of heavy metals from contaminated sediments gives a strong potential for using a growth medium to utilize phosphorus (P) in the sediment from a circular economy and bioeconomy perspective.
|
|
| 35. |
- Sar, Taner, Postdoctoral Researcher, 1989-, et al.
(författare)
-
Combining co-culturing of Paenibacillus strains and Vitreoscilla hemoglobin expression as a strategy to improve biodesulfurization
- 2021
-
Ingår i: Letters in Applied Microbiology. - : Oxford University Press (OUP). - 0266-8254 .- 1472-765X. ; 72:4, s. 484-494
-
Tidskriftsartikel (refereegranskat)abstract
- Enhancement of the desulfurization activities of Paenibacillus strains 32O-W and 32O-Y were investigated using dibenzothiophene (DBT) and DBT sulfone (DBTS) as sources of sulphur in growth experiments. Strains 32O-W, 32O-Y and their co-culture (32O-W plus 32O-Y), and Vitreoscilla hemoglobin (VHb) expressing recombinant strain 32O-Yvgb and its co-culture with strain 32O-W were grown at varying concentrations (0.1–2 mmol l-1) of DBT or DBTS for 96 h, and desulfurization measured by production of 2-hydroxybiphenyl (2-HBP) and disappearance of DBT or DBTS. Of the four cultures grown with DBT as sulphur source, the best growth occurred for the 32O-Yvgb plus 32OW co-culture at 0.1 and 0.5 mmol l-1 DBT. Although the presence of vgb provided no consistent advantage regarding growth on DBTS, strain 32O-W, as predicted by previous work, was shown to contain a partial 4S desulfurization pathway allowing it to metabolize this 4S pathway intermediate.
|
|
| 36. |
- Youngsukkasem, Supansa, et al.
(författare)
-
Rapid Biogas Production by Compact Multi-Layer Membrane Bioreactor : Efficiency of Synthetic Polymeric Membranesane Reactor for Rapid Biogas Production
- 2013
-
Ingår i: Energies. - : M D P I AG. - 1996-1073. ; 6:12, s. 6211-6224
-
Tidskriftsartikel (refereegranskat)abstract
- Entrapment of methane-producing microorganisms between semi-permeable synthetic membranes in a multi-layer membrane bioreactor (MMBR) was studied and compared to the digestion capacity of a free-cell digester, using a hydraulic retention time of one day and organic loading rates (OLR) of 3.08, 6.16, and 8.16 g COD/L·day. The reactor was designed to retain bacterial cells with uprising plug flow through a narrow tunnel between membrane layers, in order to acquire maximal mass transfer in a compact bioreactor. Membranes of hydrophobic polyamide 46 (PA) and hydroxyethylated polyamide 46 (HPA) as well as a commercial membrane of polyvinylidene fluoride (PVDF) were examined. While the bacteria in the free-cell digester were washed out, the membrane bioreactor succeeded in retaining them. Cross-flow of the liquid through the membrane surface and diffusion of the substrate through the membranes, using no extra driving force, allowed the bacteria to receive nutrients and to produce biogas. However, the choice of membrane type was crucial. Synthesized hydrophobic PA membrane was not effective for this purpose, producing 50–121 mL biogas/day, while developed HPA membrane and the reference PVDF were able to transfer the nutrients and metabolites while retaining the cells, producing 1102–1633 and 1016–1960 mL biogas/day, respectively.
|
|
