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Electronics containing growing quantities of high value and critical metals are increasingly used in automobiles. The conventional treatment practice for end-of-life vehicles (ELV) is shredding after de-pollution and partial separation of spare parts. Despite opportunities for resource recovery, the selective separation of components containing relevant amounts of critical metals for the purpose of material recycling is not commonly implemented. This article is aimed to contribute to recycling strategies for future critical metal quantities and the role of extended material recovery from ELVs. The study examines the economic feasibility of dismantling electronic components from ELVs for high value metal recycling. The results illustrate the effects of factors as dismantling time, labour costs and logistics on the economic potential of resource recovery from ELVs. Manual dismantling is profitable for only a few components at the higher labour costs in western/northern parts of Europe and applicable material prices, including the inverter for hybrid vehicles, oxygen sensor, side assistant sensor, distance and near distance sensors. Depending on the vehicle model, labour costs and current material prices, manual dismantling can also be cost-efficient for also some other such as the heating blower, generator, starter, engine and transmission control, start/stop motor, drive control, infotainment and chassis control.
Mona Arnold; Elina Pohjalainen; Sören Steger; Wolfgang Kaerger; Jan-Henk Welink. Economic Viability of Extracting High Value Metals from End of Life Vehicles. Sustainability 2021, 13, 1902 .
AMA StyleMona Arnold, Elina Pohjalainen, Sören Steger, Wolfgang Kaerger, Jan-Henk Welink. Economic Viability of Extracting High Value Metals from End of Life Vehicles. Sustainability. 2021; 13 (4):1902.
Chicago/Turabian StyleMona Arnold; Elina Pohjalainen; Sören Steger; Wolfgang Kaerger; Jan-Henk Welink. 2021. "Economic Viability of Extracting High Value Metals from End of Life Vehicles." Sustainability 13, no. 4: 1902.
Sulfate-rich mine water must be treated before it is released into natural water bodies. We tested ethanol as substrate in bioreactors designed for biological sulfate removal from mine water containing up to 9 g L−1 sulfate, using granular sludge from an industrial waste water treatment plant as inoculum. The pH, redox potential, and sulfate and sulfide concentrations were measured twice a week over a maximum of 171 days. The microbial communities in the bioreactors were characterized by qPCR and high throughput amplicon sequencing. The pH in the bioreactors fluctuated between 5.0 and 7.7 with the highest amount of up to 50% sulfate removed measured around pH 6. Dissimilatory sulfate reducing bacteria (SRB) constituted only between 1% and 15% of the bacterial communities. Predicted bacterial metagenomes indicated a high prevalence of assimilatory sulfate reduction proceeding to formation of l-cystein and acetate, assimilatory and dissimilatory nitrate reduction, denitrification, and oxidation of ethanol to acetaldehyde with further conversion to ethanolamine, but not to acetate. Despite efforts to maintain optimal conditions for biological sulfate reduction in the bioreactors, only a small part of the microorganisms were SRB. The microbial communities were highly diverse, containing bacteria, archaea, and fungi, all of which affected the overall microbial processes in the bioreactors. While it is important to monitor specific physicochemical parameters in bioreactors, molecular assessment of the microbial communities may serve as a tool to identify biological factors affecting bioreactor functions and to optimize physicochemical attributes for ideal bioreactor performance.
Malin Bomberg; Jarno Mäkinen; Marja Salo; Mona Arnold. Microbial Community Structure and Functions in Ethanol-Fed Sulfate Removal Bioreactors for Treatment of Mine Water. Microorganisms 2017, 5, 61 .
AMA StyleMalin Bomberg, Jarno Mäkinen, Marja Salo, Mona Arnold. Microbial Community Structure and Functions in Ethanol-Fed Sulfate Removal Bioreactors for Treatment of Mine Water. Microorganisms. 2017; 5 (3):61.
Chicago/Turabian StyleMalin Bomberg; Jarno Mäkinen; Marja Salo; Mona Arnold. 2017. "Microbial Community Structure and Functions in Ethanol-Fed Sulfate Removal Bioreactors for Treatment of Mine Water." Microorganisms 5, no. 3: 61.
Drainage from metal-sulphide rich rocks may cause considerable environmental stress in the form of elevated sulphate and heavy metal contamination of the environment. Mine draining effects from closed mines may be abated using indigenous and introduced microbial communities for sulphate reduction and metal precipitation at the mining site. Here we characterized the general and sulphate reducing bacterial (SRB) community of Kotalahti Mine (Finland). The mine was flooded after closure and sulphate reduction and metal precipitation was induced by addition of pig manure sludge into the Vehkankuilu shaft. Water was sampled from Vehkankuilu and Ollinkuilu shafts from depths −10, −30, −70 and −100 m 15 years after the treatment. The water in the shafts differed from each other biologically and geochemically. The shafts are not directly connected except by some fracture zones, and the Ollinkuilu shaft is used as a reference for environmental monitoring. The detected bacterial communities from both shafts contained methylotrophic γ-Proteobacteria, hydrogenotrophic and methylotrophic β-Proteobacteria and fermenting bacterial clades. The concentration of SRB was low, at most 4.0 × 103dsrB genes·mL−1, and the SRB affiliated with Desulfobulbus and Thermoanaerobacteriales clades. Despite the obvious success of the mine as an in situ bioreactor for increasing water pH and removing sulphate and heavy metals by induced sulphate reduction under suboptimal temperature, only a small portion, less than 0.5%, of the bacterial population in the mine water was SRB.
Malin Bomberg; Mona Arnold; Päivi Kinnunen. Characterization of the Bacterial and Sulphate Reducing Community in the Alkaline and Constantly Cold Water of the Closed Kotalahti Mine. Minerals 2015, 5, 452 -472.
AMA StyleMalin Bomberg, Mona Arnold, Päivi Kinnunen. Characterization of the Bacterial and Sulphate Reducing Community in the Alkaline and Constantly Cold Water of the Closed Kotalahti Mine. Minerals. 2015; 5 (3):452-472.
Chicago/Turabian StyleMalin Bomberg; Mona Arnold; Päivi Kinnunen. 2015. "Characterization of the Bacterial and Sulphate Reducing Community in the Alkaline and Constantly Cold Water of the Closed Kotalahti Mine." Minerals 5, no. 3: 452-472.
The role of sludge in renewable energy production and the final disposal of sludge are topical issues. The cost of sludge treatment account for a significant share of the total running costs of a WWTP. By increasing the efficiency of sludge treatment, significant savings can be achieved. Savings can be gained e.g. by more efficient energy utilisation of sludge, combined with optimised wastewater treatment processes. In addition to cost efficiency, environmental sustainability of the applied solutions is crucial. The energy balance and green house gas emissions can be used as tools to evaluate the sustainability of sludge treatment options. This paper presents a case-based comparison of energy balances, green house gas emissions and costs of municipal wastewater sludge process chains based on anaerobic digestion or incineration. Information from existing plants was used for conducting the study. Several utilisation options were covered for biogas energy as well for energy from sludge incineration. Based on the results, sludge incineration was the most expensive option of the studied scenarios, but justified if the heat generated can be fully utilised e.g. in district heating. Based on costs and energy balances as well as green house gas emissions it is most preferable in anaerobic digestion chains to feed the generated biogas to a gas engine to produce electricity and heat. Moreover, thermophilic anaerobic digestion can improve the overall economy of a WWTP provided that the biogas yield is sufficiently higher than in a mesophilic process. However increased odour is a risk in thermophilic digestion. The study showed that the most energy efficient process modifications are always very case bound. However the tools developed in this study are generally applicable to waste water treatment plants for similar analyses.
M. E. Arnold; E. S. Merta. Towards energy self-sufficiency in wastewater treatment by optimized sludge treatment. Water Practice and Technology 2011, 6, 1 -2.
AMA StyleM. E. Arnold, E. S. Merta. Towards energy self-sufficiency in wastewater treatment by optimized sludge treatment. Water Practice and Technology. 2011; 6 (4):1-2.
Chicago/Turabian StyleM. E. Arnold; E. S. Merta. 2011. "Towards energy self-sufficiency in wastewater treatment by optimized sludge treatment." Water Practice and Technology 6, no. 4: 1-2.
This paper focuses on the development of an on-line measurement method for siloxanes and other biogas trace compounds impeding the energy utilisation of biogas, as well as the main gas components, methane and carbon dioxide. The method is based on gas chromatography and FT-IR-analysis. The level of siloxane, hydrogen sulphide and halogens in biogas generated in a number of landfills and digesters in Finland is also presented and factors affecting the concentrations discussed. Generally, the level of biogas trace compounds hampering electricity production was lower than those measured at comparable sites in Central Europe and the US. Moreover, the paper discusses the significance of on-line monitoring of siloxane in connection to biogas-to-electricity applications and points out with activated carbon as an example the benefits of on-line siloxane measurement in the control of siloxane removal technology.
M. Arnold; T. Kajolinna. Development of on-line measurement techniques for siloxanes and other trace compounds in biogas. Waste Management 2010, 30, 1011 -1017.
AMA StyleM. Arnold, T. Kajolinna. Development of on-line measurement techniques for siloxanes and other trace compounds in biogas. Waste Management. 2010; 30 (6):1011-1017.
Chicago/Turabian StyleM. Arnold; T. Kajolinna. 2010. "Development of on-line measurement techniques for siloxanes and other trace compounds in biogas." Waste Management 30, no. 6: 1011-1017.
A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12 g m−3 h−1 (max. 30 g m−3 h−1). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH to a neutral level and efficient control of the humidity. Maintenance of the water balance was easier in a down-flow than in an up-flow process, the former consequently resulting in much better filtration efficiency. The optimum operation temperature was around 23 °C, but the styrene removal was still satisfactory at 12 °C. Seven different bacterial isolates belonging to the genera Tsukamurella, Pseudomonas, Sphingomonas, Xanthomonas and an unidentified genus in the γ group of the Proteobacteria isolated from the microflora of active peat filter material were capable of styrene degradation. The isolates differed in their capacity to decompose styrene to carbon dioxide and assimilate it to biomass. No toxic intermediate degradation products of styrene were detected in the filter outlet gas or in growing cultures of isolated bacteria. The use of these isolates in industrial biofilters is beneficial at low styrene concentrations and is safe from both the environmental and public health points of view.
M. Arnold; A. Reittu; A. Von Wright; P. J. Martikainen; M.-L. Suihko. Bacterial degradation of styrene in waste gases using a peat filter. Applied Microbiology and Biotechnology 1997, 48, 738 -744.
AMA StyleM. Arnold, A. Reittu, A. Von Wright, P. J. Martikainen, M.-L. Suihko. Bacterial degradation of styrene in waste gases using a peat filter. Applied Microbiology and Biotechnology. 1997; 48 (6):738-744.
Chicago/Turabian StyleM. Arnold; A. Reittu; A. Von Wright; P. J. Martikainen; M.-L. Suihko. 1997. "Bacterial degradation of styrene in waste gases using a peat filter." Applied Microbiology and Biotechnology 48, no. 6: 738-744.