| 1. |
- Anbalagan, Anbarasan, et al.
(författare)
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Influence of iron precipitated condition and light intensity on microalgae activated sludge based wastewater remediation
- 2017
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; , s. 1523-1530
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Tidskriftsartikel (refereegranskat)abstract
- The indigenous microalgae-activated sludge (MAAS) process during remediation of municipal wastewater was investigated by studying the influence of iron flocculation step and light intensity. In addition, availability of total phosphorous (P) and photosynthetic activity was examined in fed-batch and batch mode under northern climatic conditions and limited lighting. This was followed by a semi-continuous operation with 4 d of hydraulic retention time and mean cell residence time of 6.75 d in a photo-bioreactor (PBR) with varying P availability. The fed-batch condition showed that P concentrations of 3–4 mg L−1 were effective for photosynthetic chl. a development in iron flocculated conditions. In the PBR, the oxygen evolution rate increased with increase in the concentration of MAAS (from 258 to 573 mg TSS L−1) at higher surface photosynthetic active radiation (250 and 500 μmol m−2 s−1). Additionally, the rate approached a saturation phase at low MAAS (110 mg L−1) with higher light intensities. Semi-continuous operation with luxury P uptake and effective P condition showed stable average total nitrogen removal of 88 and 92% respectively, with residual concentrations of 3.77 and 2.21 mg L−1. The corresponding average P removal was 68 and 59% with residual concentrations of 2.32 and 1.75 mg L−1. The semi-continuous operation produced a rapidly settleable MAAS under iron flocculated condition with a settling velocity of 92–106 m h−1 and sludge volume index of 31–43 ml g−1 in the studied cases.
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| 2. |
- Ferrans, Laura, et al.
(författare)
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Chemical speciation of metals from marine sediments : assessment of potential pollution risk while dredging, a case study in southern Sweden
- 2021
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 263:January, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Contamination associated with metals is a critical concern related to their toxicity, persistence, and bio-accumulation. Trace elements are partitioned into several chemical forms, which some are more labile during fluctuations in the environment. Studying the distribution of metals between the different chemical fractions contributes to assess their bioavailability and to identify their potential risk of contamination to surrounding environments. This study concerns the speciation of metals (Pb, Cr, Ni, Zn and Fe) from sediments coming out from Malmfjärden bay, Sweden. The aim was to assess the potential risk of metal pollution during present and future dredging as well as while using dredged sediments in beneficial uses. The Tessier speciation procedure was chosen, and the results showed that low concentrations of metals were associated with the exchangeable fraction. In contrast, the major concentrations were linked to the residual part. The risk indexes (contamination factor and risk assessment code) showed that, during dredging activities, there is a low concern of pollution for Cr, Ni and Fe and a medium risk for Pb and Zn. Additionally, in all elements, the sum of non-residual concentrations was below the Swedish limits for using dredged sediments in sensitive lands. The findings suggested that the investigated metals in Malmfjärden sediments are related to low risks of spreading during using in beneficial uses.
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| 3. |
- Jani, Yahya, 1975-, et al.
(författare)
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Chemical extraction of trace elements from hazardous fine fraction at an old glasswork dump
- 2018
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 195, s. 825-830
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Tidskriftsartikel (refereegranskat)abstract
- Old glassworks siteshave been always associated with contamination by different trace elements likePb, Cd, As, Zn and others. The mixture of soil and waste glass of particlesizes <2mmat one of the oldest Swedish glassworks (the Pukeberg) was studiedby analyzing the trace elements content, organic content (3.6%) and pH (7.4).The results showed hazardous concentrations of Pb (1525 mg/kg), Ba (1312mg/kg), Sb (128 mg/kg), Cd (36 mg/kg), As (118 mg/kg), Zn (1154mg/kg) and Co(263 mg/kg) exceeded the Swedish guidelines of contaminated soil. Batchchemical extraction by the chelating agents EDTA, DTPA and the biodegradableNTA were performed to study the effect of chelating agent concentration and mixingtime on the extraction efficiencies by following a Box-Wilson design ofexperiments. The results displayed good extraction efficiencies (less than 41%)of Pb, Cd, As and Zn by the EDTA, DTPA and NTA, which seemed depends on thetype of chelator. In addition, high correlation between the extraction efficiencies,the chelators concentration and mixing time was found based on the statisticaland experimental results.
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| 4. |
- Jani, Yahya, 1975-, et al.
(författare)
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Physicochemical and toxicological characterization of hazardous wastes from an old glasswork dump at southeastern part of Sweden
- 2019
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 237, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- More than 34 old glasswork sites in the southeastern part of Sweden pose a permanent threat to human and environmental health due to the presence of toxic trace elements in open dumps with glass waste. The possibility of leaching of trace elements from different fractions of the disposed waste needed to be assessed. In the present investigation, leachate from a mixture of soil and waste glass of particle sizes of less than 2mm (given the name fine fraction) was characterized by analyzing the pH (7.3), total organic content (TOC<2%), organic matter content (4.4%), moisture content (9.7%), chemical oxygen demand (COD, 163mg/kg) and trace elements content, being the values in accordance to the Swedish guidelines for landfilling of inert materials. However, very high trace elements content was found in the fine fraction as well as in all colors of waste glass, whose values were compatible to hazardous waste landfill class. Tests with Lepidium sativum growing in the fine fraction as substrate revealed chronic toxicity expressed as inhibition of root biomass growth in 11 out of 15 samples. Additionally, leachate from fine fractions posed acute toxicity to genetically modified E. coli (Toxi-Chromotest). This study highlights the importance of combining physicochemical characterization with toxicity tests for both solid waste and leachate obtained from different waste fractions for proper hazardousness assessment supporting decision making on remediation demands.
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| 5. |
- Lu, L., et al.
(författare)
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Refinement and predicting formaldehyde concentrations of indoor fabric : Effects of temperature and humidity
- 2023
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Ingår i: Chemosphere. - : Elsevier Ltd. - 0045-6535 .- 1879-1298. ; 342
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Tidskriftsartikel (refereegranskat)abstract
- Indoor air pollution resulting from volatile organic compounds (VOCs) is a significant health concern, especially formaldehyde. Therefore, predicting indoor formaldehyde concentration is essential for environmental control. In this research, the authors develop a thermal and wet coupling calculation model of porous fabric that considers the influence of different phases of wet components and the coupling effect of heat and humidity on formaldehyde migration. We propose a modified calculation method of the formaldehyde mass transfer characteristic parameters of fabric to obtain the diffusion coefficient D and partition coefficient K. The heat and humidity coupling model and formaldehyde mass transfer model of fabric are simultaneously solved, and the authors analyze the influence mechanism of fabric loading rate, fabric type, temperature, and humidity on indoor formaldehyde mass transfer characteristics. We study the variation trend of fabric formaldehyde mass transfer characteristics coefficient and the temporal and spatial distribution of indoor formaldehyde concentration. The theoretical model is applied to practical problems by pre-evaluating the indoor formaldehyde concentration of decorated residential buildings in typical climate areas of China before occupancy. The authors obtain the variation rule of indoor formaldehyde concentration of residential buildings under typical hot and humid climate conditions, building materials, furniture, and fabrics. To provide theoretical support for indoor environmental control and human health protection.
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| 6. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Emissions from simulated deep-seated fires in domestic waste
- 2008
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 70:4, s. 626-39
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Tidskriftsartikel (refereegranskat)abstract
- The emissions from deep-seated fires in domestic waste have been investigated. The gas phase yields of PAH, PCDD/F, PCB, HCB, particles, and metals associated to the particulate matter were analysed during a series of simulated deep-seated fires. The method of extinguishment was varied and in cases where water was used for extinguishment, the runoff water was analysed for PAH, PCDD/F, PCB, hexachlorobenzene, and metals. In total six tests were performed. In four of the tests, samples of the fire residue were analysed for PCDD/F, PCBs, and chlorobenzenes.
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| 7. |
- Mutafela, Richard N., 1984-, et al.
(författare)
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Radiometrical and physico-chemical characterisation of contaminated glass waste from a glass dump in Sweden
- 2020
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 241
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Tidskriftsartikel (refereegranskat)abstract
- Around former glass factories in south eastern Sweden, there are dozens of dumps whose radioactivity and physico-chemical properties were not investigated previously. Thus, radiometric and physico-chemical characteristics of waste at Madesjö glass dump were studied to evaluate pre-recycling storage requirements and potential radiological and environmental risks. The material was sieved, hand-sorted, leached and scanned with X-Ray Fluorescence (XRF). External dose rates and activity concentrations of Naturally Occurring Radioactive Materials from 238U, 232Th series and 40K were also measured coupled with a radiological risk assessment. Results showed that the waste was 95% glass and dominated by fine fractions (<11.3 mm) at 43.6%. The fine fraction had pH 7.8, 2.6% moisture content, 123 mg kg−1 Total Dissolved Solids, 37.2 mg kg−1 Dissolved Organic Carbon and 10.5 mg kg−1 fluorides. Compared with Swedish EPA guidelines, the elements As, Cd, Pb and Zn were in hazardous concentrations while Pb leached more than the limits for inert and non-hazardous wastes. With 40K activity concentration up to 3000 Bq kg−1, enhanced external dose rates of 40K were established (0.20 μSv h−1) although no radiological risk was found since both External Hazard Index (Hex) and Gamma Index (Iγ) were <1. The glass dump needs remediation and storage of the waste materials under a safe hazardous waste class ‘Bank Account’ storage cell as a secondary resource for potential future recycling. © 2019 Elsevier Ltd
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