| 1. |
- Norén, Anna, 1989, et al.
(författare)
-
The effects of electrochemical pretreatment and curing environment on strength and leaching of stabilized/solidified contaminated sediment
- 2024
-
Ingår i: Environmental Science and Pollution Research. - : Springer Nature. - 0944-1344 .- 1614-7499. ; 31:4, s. 5866-5880
-
Tidskriftsartikel (refereegranskat)abstract
- Stabilization and solidification (S/S) is known to improve the structural properties of sediment and reduce contaminant mobility, enabling the utilization of dredged contaminated sediment. Further reduction of contaminants (e.g., tributyltin (TBT) and metals) can be done using electrochemical treatment prior to S/S and could potentially minimize contaminant leaching. This is the first study on how electrochemical pretreatment affects the strength and leaching properties of stabilized sediments. It also investigates how salinity and organic carbon in the curing liquid affect the stabilized sediment.
|
|
| 2. |
- Norén, Anna, 1989
(författare)
-
A Method for Treatment of Contaminated Dredged Sediment: Electrolysis Combined with Stabilization and Solidification
- 2022
-
Ingår i: Book of abstracts: Linnaeus ECO-TECH '22. - 9789189460850
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Contaminated sediment is a worldwide concern. In ports, where large quantities of sediment need to be managed, the level of contaminants limits the possibility to use the dredged sediment. New legislations have reduced the possibility to dispose of sediment in landfills and out at sea, and are instead encouraging the use of the dredged masses. A method that enables the use of fine-grained sediment in construction is the stabilization and solidification technique (S/S). If contaminants are removed prior to stabilization, the stabilized sediment may leach less contaminants. Electrochemical treatment is a potential treatment technique that has the potential to degrade organic contaminants and recover metals. Electrochemical treatment was tested at laboratory scale to degrade toxic tributyltin (TBT) and remove metals from marine sediment. After the electrolysis, the sediment was stabilized using the S/S technique, and the effect of electrochemical pretreatment on the strength and leaching properties of the stabilized sediment was investigated. Finally, the climate impacts of the investigated methods are assessed depending on the metal content in the sediment. The results indicate that electrochemical pretreatment could be done to lower the leaching of contaminants from S/S sediment and that the metal recovery could be beneficial, especially if the sediment is heavily contaminated with metals.
|
|
| 3. |
- Norén, Anna, 1989, et al.
(författare)
-
Removal of organotin compounds and metals from Swedish marine sediment using Fenton’s reagent and electrochemical treatment
- 2022
-
Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 29:19, s. 27988-28004
-
Tidskriftsartikel (refereegranskat)abstract
- Metal and tributyltin (TBT) contaminated sediments are problematic for sediment managers and the environment. This study is the first to compare Fenton’s reagent and electrochemical treatment as remediation methods for the removal of TBT and metals using laboratory-scale experiments on contaminated dredged sediment. The costs and the applicability of the developed methods were also compared and discussed. Both methods removed > 98% TBT from TBT-spiked sediment samples, while Fenton’s reagent removed 64% of the TBT and electrolysis 58% of the TBT from non-spiked samples. TBT in water phase was effectively degraded in both experiments on spiked water and in leachates during the treatment of the sediment. Positive correlations were observed between TBT removal and the added amount of hydrogen peroxide and current density. Both methods removed metals from the sediment, but Fenton’s reagent was identified as the most potent option for effective removal of both metals and TBT, especially from highly metal-contaminated sediment. However, due to risks associated with the required chemicals and low pH level in the sediment residue following the Fenton treatment, electrochemical treatment could be a more sustainable option for treating larger quantities of contaminated sediment.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Svensson, Nina, 1988-, et al.
(författare)
-
Integrated cost and environmental impact assessment of management options for dredged sediment
- 2022
-
Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 138, s. 30-40
-
Tidskriftsartikel (refereegranskat)abstract
- Large quantities of sediment must be dredged regularly to enable marine transport and trade. The sediments are often polluted, with e.g. metals, which limits the management options. The aim of this study has been to assess costs and environmental impacts (impact on climate, marine organisms, etc.) of different management options for polluted dredged sediment, by combining life-cycle assessment (LCA) of the climate impact, scoring of other environmental aspects and a cost evaluation. This approach has been used to study both traditional and new management alternatives for a real port case. The studied options include landfilling, deep-sea disposal, construction of a port area using a stabilization and solidification (S/S) method, and a combination of the aforementioned methods with the innovative option of metal recovery through sediment electrolysis. The LCA showed that deep-sea disposal had the lowest climate impact. The assessment of the other environmental impacts showed that the result varied depending on the pollution level and the time perspective used (short or long-term). Using sediment for construction had the highest climate impact, although other environmental impacts were comparably low. Electrolysis was found to be suitable for highly polluted sediments, as it left the sediment cleaner and enabled recovery of precious metals, however the costs were high. The results highlight the complexity of comparing different environmental impacts and the benefits of using integrated assessments to provide clarity, and to evaluate both the synergetic and counteracting effects associated with the investigated scenarios and may aid early-stage decision making.
|
|
| 7. |
- Norén, Anna, 1989, et al.
(författare)
-
Low impact leaching agents as remediation media for organotin and metal contaminated sediments
- 2021
-
Ingår i: Journal of Environmental Management. - : Academic Press. - 0301-4797 .- 1095-8630. ; 282
-
Tidskriftsartikel (refereegranskat)abstract
- All over the world, elevated levels of metals and the toxic compound tributyltin (TBT) and its degradation products are found in sediments, especially close to areas associated with shipping and anthropogenic activities. Ports require regular removal of sediments. As a result, large volumes of often contaminated sediments must be managed. The aim of this study was to investigate enhanced leaching as a treatment method for organotin (TBT) and metal (Cu and Zn) contaminated marine sediments. Thus, enabling the possibility to reuse these cleaner masses e.g. in construction. In addition to using acid and alkaline leaching agents that extract the OTs and metals but reduce the management options post treatment, innovative alternatives such as EDDS, hydroxypropyl cellulose, humic acid, iron colloids, ultra-pure Milli-Q water, saponified tall oil (“soap”), and NaCl were tested. Organotin removal ranged from 36 to 75%, where the most efficient leaching agent was Milli-Q water, which was also the leaching agent achieving the highest removal rate for TBT (46%), followed by soap (34%). The TBT reduction accomplished by Milli-Q water and soap leaching enabled a change in Swedish sediment classification from the highest class to the second highest class. The highest reduction of Zn was in HPC leached samples (39% removal) and Cu in EDDS leached samples (33% removal). Although high metal and OT leaching were achieved, none of the investigated leaching agents are sufficiently effective for the removal of both metals and OTs. The results of this study indicate that leaching with ultra-clean water, such as Milli-Q water, may be sufficient to treat TBT contaminated sediments and potentially allow mass reuse. © 2021 The Authors
|
|
| 8. |
- Norén, Anna, 1989
(författare)
-
Management and Treatment of Organotin and Metal Contaminated Dredged Sediment
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modern society is dependent on international trade and most traded goods are transported by sea. To enable this, regular dredging must be done to maintain water depth in ports and waterways, resulting in large quantities of often contaminated sediment that must be handled. Management options are limited due to regulations and depend on the content of contaminants such as tributyltin (TBT) and metals (e.g., zinc and copper) in the sediment. Consequently, there is a need to investigate new treatment techniques and evaluate the sustainability of management alternatives. In this thesis, several techniques to remove TBT and metal from sediment were developed and tested in laboratory studies, including chemical oxidation by electrolysis and Fenton’s reagent (Fenton) (Paper III), leaching with ultra-pure water, EDDS, saponified tall oil, iron colloids, humic acid, hydroxypropyl cellulose, and acid and alkaline solutions (Paper II). The highest TBT removal from natural sediment was reached using Fenton (64%) followed by electrolysis (58%). On TBT spiked sediment, Fenton and electrolysis reduced the TBT content by 98% by 100% respectively. In spiked water, TBT was degraded 100% by electrolysis. The most effective method for simultaneous TBT and metal removal was Fenton. However, due to the low pH of Fenton residue, electrolyzed sediment was instead chosen for stabilization and solidification, a method that forms a concrete-like product that could be used in construction (Paper IV). The impacts of electrolysis pre-treatment on compression strength and leaching patterns were investigated. The results show that stabilized pre-treated sediment leached less but had lower compression strength than stabilized untreated samples. The surrounding environment during curing was important, as a saline solution increased the compression strength and decreased TBT leaching, but increased metal leaching compared to a less saline solution. Environmental impacts and costs associated with different sediment management strategies were studied using life cycle assessment (Paper V) and integrated monetary and environmental multicriteria analysis (Paper I). Metal recovery from sediment was identified as a potential future alternative, with increasing metal prices and economic incentives as highly contaminated sediments cost more to handle. However, effective and sustainable metal recovery techniques need to be further developed. The results highlight the importance of individually assessing each site when evaluating risk, determining management strategies, and assessing short- and long-term environmental impacts. The developed methods are useful for identifying economic and environmental conflicts and synergetic effects and could be useful tools in decision-making processes. The results of this thesis could contribute further to the development of full-scale treatment methods to remediate and enable the use of contaminated dredged sediment.
|
|
| 9. |
- Norén, Anna, 1989, et al.
(författare)
-
Integrated assessment of management strategies for metal-contaminated dredged sediments : What are the best approaches for ports, marinas and waterways?
- 2020
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 716
-
Tidskriftsartikel (refereegranskat)abstract
- Sediments in ports, marinas and waterways around the world are often contaminated with metals arising from anthropogenic activities. Regular dredging is needed to achieve an appropriate water depth and reduce the environmental impact of pollutants. The aim of this study was to develop an integrated assessment method for comparing various management strategies for dredged sediments at six case study sites in Sweden. Short- and long-term environmental impacts were investigated for different management approaches, including landfilling, deep-sea disposal, metal extraction in combination with the two aforementioned, and natural recovery (no dredging). The potential value of metals in the sediments was estimated using sediment metal contents and current metal prices. Additionally, an assessment of how metal extraction could result in lower management costs was carried out. The cost of the different management approaches was calculated and evaluated together with the corresponding environmental impacts. This study shows that there is a monetary value in dredged materials, in terms of metal content, and that the materials can potentially be used for metal extraction. Metal extraction may also help to reduce the management costs, as cleaner materials are cheaper to handle. The choice of metal recovery method is important in both monetary and environmental terms, potentially contributing to a circular economy. In the future, metal recovery may become more profitable, as technologies are improved, and due to probable increases in metal prices and landfill costs.
|
|
| 10. |
- Norén, Anna, 1984-
(författare)
-
Caring, Sharing, and Childbearing : Essays on Labor Supply, Infant Health, and Family Policies
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Essay I: I study the consequences on labor market outcomes and sick leave of having an elderly parent in need of care. Caring for an elderly parent may be associated with opportunity costs such as productivity loss on the labor market if informal caregivers are of working age. Using Swedish register data I compare the labor market outcome trajectories of adult children before and after their parent suffer a health shock. I find that employment and income of adult children are slightly reduced in the years leading up to the demise of their parent, but that the size of the impact is largest in the year, and the year after, parental demise. I also find that daughter's sick leave absence increases in the year that the parent dies. No effects on labor market outcomes are found from having a parent suffering stroke. Furthermore, I find no clear gender differences between sons and daughters in the impact of having a parent with increased care demand. Taken together, the results suggest that the opportunity costs of parental care need in the form of adverse labor market impacts are small.
|
|
