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- Elgh-Dalgren, Kristin, 1980-, et al.
(author)
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Laboratory and pilot scale soil washing of PAH and arsenic from a wood preservation site : Changes in concentration and toxicity
- 2009
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In: Journal of Hazardous Materials. - Amsterdam : Elsevier. - 0304-3894 .- 1873-3336. ; 172:2-3, s. 1033-1040
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Journal article (peer-reviewed)abstract
- Soil washing of a soil with a mixture of both polycyclic aromatic hydrocarbons (PAH) and As was evaluated in laboratory and pilot scale, utilizing both single and mixtures of different additives. The highest level of decontamination was achieved with a combination of 0.213 M of the chelating agent MGDA and 3.2xCMC* of a nonionic, alkyl glucoside surfactant at pH 12 (Ca(OH)2). This combination managed to reach Swedish threshold values within 10 min of treatment when performed at elevated temperature (50°C), with initial contaminant concentrations of As = 105±4 mg/kg and US-EPA PAH16 = 46.0±2.3 mg/kg. The main mechanisms behind the removal were the pH-effect for As and a combination of SOM-ionization as a result of high pH and micellar solubilization for PAHs. Implementation of the laboratory results utilizing a pilot scale equipment did not improve the performance, which may be due to the shorter contact time between the washing solution and the particles, or changes in physical characteristics of the leaching solution due to the elevated pressure utilized. The ecotoxicological evaluation, Microtox®, demonstrated that all soil washing treatments increased the toxicity of soil leachates, possibly due to increased availability of contaminants and toxicity of soil washing solutions to the test organism.
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- Nehrenheim, Emma, et al.
(author)
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Metal retention on pine bark and blast furnace slag – On-site experiment for treatment of low strenght landfill leachate
- 2008
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In: Bioresource Technology. - Amsterdam : Elsevier. - 0960-8524 .- 1873-2976. ; 99:5, s. 998-1005
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Journal article (peer-reviewed)abstract
- Treatment of landfill leachate using blast furnace slag and pine bark as reactive sorbents was studied in an in situ column experiment at the Lilla Nyby landfill site in Eskilstuna, Sweden. The columns were filled with approximately 10 l of each sorbent and leachate was supplied at three different flow rates during a period of 4 months. Samples of inflow and outflow were collected three times a week and were analyzed for physical and chemical parameters, including concentrations of some metals, and toxicity. It was found that pine bark removed metals more efficiently than did the blast furnace slags; that Zn was most efficiently retained in the filters and that both retention time and initial concentration played an important role in the sorption process. It was also observed that the pine bark column did not release COD. No toxicity of the untreated or the treated leachate was found with the test organisms and test responses used. © 2007 Elsevier Ltd. All rights reserved.
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- Nehrenheim, Emma, 1979-, et al.
(author)
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Treatment of Landfill Leachate Using Filter Substrates
- 2005
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In: Sardinia 2005. - Cagliari : CISA, Environmental Sanitary Engineering Centre.
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Conference paper (peer-reviewed)abstract
- Three by-products from the steel and paper manufacturing industries have been tested as filter materials for removal of heavy metals in metal solution and in landfill leachate. Laboratory experiments were used to determine the capacity of the materials to remove heavy metals. A column set-up at a landfill site examined the field application possibilities of pine bark, amorphous and crystalline blast furnace slag. All three materials have shown large potential for removal of heavy metals inmetal solution also when the concentrations are low. On-site treatment however was distrurbed by factors not present in batch experiments. Physical parameters such as pH and electric conductivity of the water stream were not significantly affected by the treatment.
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- Ribé, Veronica, et al.
(author)
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Assessment of the safety and performance of a low-cost filter material for treatment of landfill leachate and industrial wastewater using an integrated approach based on ecotoxicological testing and chemical analysis
- 2009
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In: ICCE 2009 Stockholm. - Stockholm : Universitetsservice.
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Conference paper (peer-reviewed)abstract
- Ecotoxicological tests are frequently used as a complement to chemical analysis in hazard assessment of contaminated water, as they can detect toxic effects resulting from interactions of contaminants. They are, however, less commonly used in water treatment method development, where they can provide a rapid and low-cost means of evaluating the efficiency and safety of a new treatment method. This is particularly valuable when treating waters with a complex contaminant matrix, such as landfill leachates and industrial wastewaters.Pine bark, which is an industrial by-product from the forestry industry, has been extensively investigated as a low-cost filter material and it has been shown to efficiently remove metals from solution, storm water run-off and landfill leachate. Additionally, it has also been demonstrated to retain phosphorous, uranium and organic compounds, such as lindane and pentachlorophenol, from water. Pine bark is therefore an interesting alternative to more expensive methods for treating waters contaminated with a mixture of organic and inorganic pollutants, e.g. activated carbon.Although a promising low-cost sorbent, concerns have been raised about using pine bark for water treatment due to the leaching of organic acids and phenols from the unused filter material, particularly during the initial filtration phase. To ensure the environmental benefits and safety of using the filter material it is important to determine the extent and composition of the leaching of organic material from the unused material.This study shows how an ecotoxicological test battery in combination with chemical analyses was used to evaluate the safety of using pine bark for water treatment. Leachates from the ISO standardized leaching test 12457-2 was analysed for metals, dissolved organic carbon (DOC) and phenols. The toxicity of leachates with and without pH adjustment was assessed using the freshwater crustacean Daphnia magna. The performance of the filter material when treating low-strength landfill leachate and industrial wastewater was assessed in batch tests followed by chemical analysis and a bioassay test battery consisting of bacteria, aquatic plants and invertebrates.
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| 7. |
- Ribé, Veronica, et al.
(author)
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Leaching of contaminants from untreated pine bark in a batch study : Chemical analysis and ecotoxicological evaluation
- 2009
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In: Journal of Hazardous Materials. - Amsterdam : Elsevier. - 0304-3894 .- 1873-3336. ; 163:2-3, s. 1096-1100
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Journal article (peer-reviewed)abstract
- Low cost sorbents have been widely studied in recent years in the search for filter materials that retain contaminants from water. One promising, low cost material is pine bark, a by-product from the forest industry. Many studies have shown that pine bark has great potential for the treatment of metals and organic substances, as a replacement for other commercial sorbents such as active carbon. However, some potential problems are introduced through the use of natural materials and by-products. One such problem that must be addressed is the possibility of leaching of contaminants from the filter material, especially in the initial filtration step or during flushes of lightly contaminated water, e.g. during rainfall for on-site treatment of storm water or landfill leachate. The aim of this preliminary study was therefore to identify potential risks and limitations of using pine bark as a filter material. Leachate from a standardized batch test was analysed for metals, dissolved organic carbon (DOC) and phenols. In addition to these chemical analyses, an ecotoxicological test was conducted using the test organism Daphnia magna. The results showed significant leaching of DOC and some metals. Only a small fraction of the DOC was present as phenols. The leachate was however found to be toxic to the test organism without pH adjustment, and the EC50 was established at an approximate leachate concentration of 40%. This was concluded to be related to the low pH in the eluate, since no toxicity was observed after pH adjustment before the toxicity tests. © 2008 Elsevier B.V. All rights reserved.
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- Waara, Sylvia, 1958-, et al.
(author)
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An Assessment of the Potential Toxicity of Runoff from an Urban Roadscape During Rain Events
- 2008
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In: Environmental Science and Pollution Research. - Heidelberg : Springer Berlin/Heidelberg. - 0944-1344 .- 1614-7499. ; 15:3, s. 205-210
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Journal article (peer-reviewed)abstract
- Goal, Scope and BackgroundThe potential negative impact of urban storm water on aquatic freshwater ecosystems has been demonstrated in various studies with different types of biological methods. There are a number of factors that influence the amount and bioavailability of contaminants in storm water even if it is derived from an area with a fairly homogenous land use such as a roadscape where a variation in toxicity during rain events might be expected. There are only a few previous investigations on the toxicity of highway runoff and they have not explored these issues extensively. The main objective of this study is therefore to characterize the potential toxicity of highway runoff during several rain events before it enters a detention pond in VästerOas, Sweden, using laboratory bioassays with test organisms representing various functional groups in an aquatic ecosystem. The results are to be used for developing a monitoring program, including biological methods.Materials and MethodsThe storm water was sampled before the entrance to a detention pond, which receives run-off from a highway with approximately 20,000 vehicles a day. The drainage area, including the roadscape and vegetated areas, is 4.3 ha in size. Samples for toxicity tests were taken with an automatic sampler or manually during storm events. In total, the potential toxicity of 65 samples representing 15 different storm events was determined. The toxicity was assessed with 4 different test organisms; Vibrio fischeri using the Microtox® comparison test, Daphnia magna using Daphtoxkit-F™agna, Thamnocephalus platyurus using the ThamnotoxkitF™ and Lemna minor, duckweed using SS 028313.Results and DiscussionOf the 65 samples, 58 samples were tested with DaphniatoxkitF™agna, 57 samples with the Microtox® comparison test, 48 samples with ThamnotoxkitF™ and 20 samples with Lemna minor, duckweed. None of the storm water samples were toxic.No toxicity was detected with the Lemna minor test, but in 5 of the 23 samples tested in comparison to the control a growth stimulation of 22–46% was observed. This is in accordance with the chemical analysis of the storm water, which indicated rather large concentrations of tot-N and tot-P. In addition to the growth stimulation, morphological changes were observed in all the 5 samples from the winter event that was sampled. The lack of toxicity observed in our study might be due to a lower traffic intensity (20,000 vehicles/day) at the site and the trapping of pollutants in the vegetated areas of the roadscape, resulting in much smaller loads of pollutants in the storm water than in some previous studies.ConclusionsEcotoxicological evaluations of storm water including run off from rain events from urban roadscape studies clearly reveal that toxicity may or may not be detected depending upon site, storm condition and the test organism chosen. However, storm water might not be as polluted as previously reported nor may the first flush be such a widespread phenomenon as we originally expected. In this study, there was also a good correlation between pollutant load measured and the lack of toxicity. The test organisms chosen in this study are commonly used in effluent control programs in Sweden and other countries, which makes it possible to compare the results with those from other effluents. In this study, only acute toxicity tests were used and further studies using chronic toxicity tests, assays for genotoxic compounds or in situ bioassays might reveal biological effects at this site. Furthermore, most of the samples were taken in spring, summer or fall and it is possible that winter conditions might alter the constituents in the storm water and, thus, the toxicity of the samples.Recommendations and PerspectivesConsidering the complex nature of run off from urban roadscapes, it will be virtually impossible to evaluate properly the potential hazard of particular storm water and the efficiency of a particular treatment strategy from only physical and chemical characterizations of the effluent. Therefore, despite the lack of toxicity detected in this study, it is recommended that toxicity tests or other biological methods should be included in evaluations of the effects of runoff from roadscapes. © 2008 Springer-Verlag.
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