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  • 1.
    Cetecioglu, Zeynep
    et al.
    Istanbul Tech Univ, Fac Civil Engn, Dept Environm Engn.
    Akyol, Cagri
    Ince, Orham
    Coban, Halil
    Koksel, Gozde
    Oz, Nilgun Ayman
    Ince, Bahar
    Individual and combined inhibitory effects of methanol and toluene on acetyl-CoA synthetase expression level of acetoclastic methanogen, Methanosaeta concilii2015In: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208Article in journal (Refereed)
    Abstract [en]

    Organic solvents found in waste streams can be inhibitory to microbial communities in wastewater treatment plants. In this study, possible inhibitory effects of commonly used organic solvents, methanol and toluene, were investigated in batch anaerobic digestion tests. Anaerobic sludges were fed with acetate repeatedly and exposed to various concentrations of toluene, methanol and mixture of them. Expression level of the key enzyme of acetoclastic methanogenesis, acetyl-CoA synthetase 1 (Acs1), was determined by reverse transcriptase real time PCR. Additionally, active populations of Methanosaeta spp. were monitored and quantified by fluorescent in situ hybridization (FISH). Transcript abundance of Acs1 was 1.31 x 10(6) mRNAs ml(-1) in the control reactors; whereas, singular methanol exposure of 0.1 M, 0.3 M, 0.5 M and 1.0 M and methanol + toluene combination of 1.0 M + 0.5 mM and 1.0 M + 1.5 mM did not cause any significant effect on the acetyl-CoA expression level. However, singular toluene-exposed serum bottle reactors were completely inhibited after 3rd exposure at all concentrations from 0.5 mM to 4.0 mM. FISH results for singular methanol and toluene additions as well as their combination in the ranges studied showed no particular effect on the relative abundance of Methanosaeta spp. cells. (C) 2015 Elsevier Ltd. All rights reserved.

  • 2.
    Cetecioglu, Zeynep
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Ince, Bahar
    Anaerobic sulfamethoxazole degradation is driven by homoacetogenesis coupled with hydrogenotrophic methanogenesis2016In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 90Article in journal (Refereed)
    Abstract [en]

    In this study, microbial community dynamics were assessed in two lab-scale anaerobic sequencing batch reactors (ASBRs). One of the reactors was fed by synthetic pharmaceutical industry wastewater with sulfamethoxazole (SMX) as the test reactor and the other without sulfamethoxazole as the control reactor. DNA based DGGE results indicated that Clostiridum sp. became dominant in the SMX reactor while the inoculum was dominated with Firmicutes (61%) and Methanomicrobiales (28%). However their abundances in active community decreased through the last phase. Also the abundance of hydro-genotrophs was high in each phase, while acetoclastic methanogens disappeared in the last phase. Q-PCR analysis revealed that there is a significant reduction in the bacterial community approximately 84%, while methanogens increased to 97% through the operation. Additionally an increase in the expression level of bacterial and methanogenic 16S rRNA (60% and 20%, respectively) was detected. Significant correlation between microbial community and the reactor operation data was found. The study demonstrated that the microbial community maintains the system stability under high antibiotic concentration and long-term operation by homoacetogenesis coupled with hydrogenotrophic methanogenesis.

  • 3.
    Das, O.
    et al.
    Wood and Bionanocomposites, Material Science Division, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, 97187, Sweden.
    Kim, N. K.
    Centre for Advanced Composite Materials, Department of Mechanical Engineering, The University of Auckland, Auckland, 1142, New Zealand.
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Bhattacharyya, D.
    Centre for Advanced Composite Materials, Department of Mechanical Engineering, The University of Auckland, Auckland, 1142, New Zealand.
    Johansson, E.
    Department of Plant Breeding, Faculty of Landscape Planning, Horticulture and Crop Production Sciences, Swedish University of Agricultural Sciences, Alnarp, 23053, Sweden.
    Xu, Q.
    School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210014, China.
    Holder, Shima
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    Naturally-occurring bromophenol to develop fire retardant gluten biopolymers2020In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 243, article id 118552Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to impart fire retardancy in wheat gluten polymer through naturally-occurring additives such as lanosol. The fire properties of lanosol were compared with two other conventional brominated fire retardants (Tetrabromobisphenol A and Hexabromocyclododecane). Samples containing fire retardants and gluten were prepared through compression moulding process and then characterised for their fire and mechanical properties. All fire retardants enhanced the reaction-to-fire and thermal properties of gluten while generating V-0 (i.e. vertical position and self-extinguished) ratings in the UL-94 test. The presence of all the fire retardants increased the modulus of the gluten polymer but the fire retardant particles were detrimental for the tensile strength. Nevertheless, lanosol addition delayed ignition and lowered peak heat release rate of gluten by the maximum amount, thereby leading to relatively higher fire performance index (compared to the other fire retardants). Lanosol also allowed the gluten to create a dense char barrier layer during burning that impeded the transfer of heat and flammable volatiles. The fact that only 4 wt% lanosol was able to cause self-extinguishment under direct flame and reduce peak heat release rate by a significant 50% coupled with its inherent occurrence in nature, raises the question if lanosol can be a potential fire retardant in polymeric systems, although it is a bromophenol.

  • 4.
    Kharazmi, Parastou
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Evaluation of Innovative Rehabilitation Technologies Utilising Polymer Composites for Aging Sewer Systems2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Water and wastewater sewer system maintenance is among the costliest aspects of infrastructure investment. The replacement of deteriorated lines is a difficult and expensive process that causes community disturbance and is generally not conducted fast enough to meet demand. To keep up with the rate of deterioration, the use of alternative rehabilitation technologies using polymer linings has increased significantly in recent years, both within Sweden and worldwide. Compared to the traditional pipe replacement method, these technologies are cost-effective, create less community disturbance, and offer a quick return to the service for the line. The main function of polymeric lining is to stabilise the condition of the pipeline, eliminate deterioration, and thereby extend the pipeline’s service life. Although rehabilitation technologies employing polymeric systems have been in use for over 30 years, there have been few technical assessments of either these technologies or the materials involved. Data gathered through the evaluation of these innovative technologies can make their benefits and limitations more widely understood, and can also be used to increase the effectiveness of the rehabilitation process in future.

    The main objective of this work was to contribute to an improved understanding of the most commonly used materials and methods employed in rehabilitation of wastewater and other applicable sewer lines in residential buildings in Sweden. The primary objective was not to prove that the emerging rehabilitation technologies work, but rather to increase knowledge of their weaknesses and strengths, identify any issues, and provide a technical assessment to support realistic expectations of pipeline rehabilitation. Gathering technical information in this way will help with the planning of future investigations; moreover, collecting extensive data will help to increase the effectiveness of the renewal works, aid progress in the field, and improve predictions regarding longevity and service life.

    As pipeline rehabilitation is still considered novel, and owing to the general lack of available data on the subject, a multi-approach study was carried out: this included evaluation of the polymeric materials’ performance in the presence of deteriorative factors, assessing the in-service state of the materials and lined sewers previously installed, monitoring the level of quality control implemented during previous rehabilitation works, and evaluating the environmental impacts of using pipe-lining technologies compared to pipe replacement. The techniques discussed included rehabilitation with epoxy and polyester resin-based lining materials, applied with brush-on and spray-on techniques, and cured-in-place pipe lining (installed by sending a resin-impregnated flexible tube inside the host pipe).

    Degradation of the resin-based lining materials was investigated via artificial aging involving immersion in water at elevated temperatures. The changes in materials that occurred during accelerated laboratory aging were tracked by means of various tests, including thermal and mechanical analyses, water absorption measurements and microscopy. The analysis focused on reinforced polyester-based and toughened epoxy-based lining materials in order to gain a better understanding of their performance as pipe lining. Moreover, the previously installed lined pipes and lining materials were also studied during laboratory examinations to evaluate the in-service performance of the materials and techniques under operating conditions over time, as well as to identify common defects. The state of the materials and the lined pipe were studied by means of different investigative methods, including visual inspection, microscopy, Fourier transform infrared spectroscopy, thickness measurement, thermal and mechanical analyses. This PhD work also includes an investigation to determine the level of quality control carried during some previous rehabilitation works. Data on the quality evaluation of previous rehabilitation works were gathered during visits to the work sites, as well as by analysing lined pipes that had already been installed. Finally, a comparative life-cycle assessment was undertaken to compare the environmental impacts of pipe replacement with those of alternative innovative rehabilitations, such as CIPP and coatings with polyester and epoxy polymeric systems. Data obtained from an LCA tool were used to facilitate comparison from an environmental perspective.

    Results from artificial aging in the lab indicated that the properties of polymeric lining materials changed significantly when high temperatures were combined with water exposure. However, the aging testing conducted for this study also found that the materials performed relatively well at temperatures close to the average temperatures inside sewerage systems. The results revealed that the polyester-based lining material was less sensitive when compared with epoxy-based lining materials during stimulated aging. Moreover, results from the in-service field demonstration (involving examination of 12 samples with up to 10 years of service, including reinforced polyester and modified epoxy linings or cured-in-place pipe (CIPP) lining) showed minimal evidence that the materials underwent significant deterioration after installation; instead, a majority of the common defects were found to be related to poor-quality installation practices. Because very few field samples were available to study, conclusions regarding overall performance could not be drawn. However, there is no evidence that these materials will not perform as expected during their service life when properly installed.

    Evaluating quality control of previous rehabilitation work revealed a gap between theory and practice where the level of quality control and documentation was concerned; furthermore, it also emerged that quality control and documentation is crucial to both the prevention of common issues and the overall effectiveness of the rehabilitation. Accordingly, a series of recommendations regarding the development of comprehensive quality control and quality assurance procedures (QC/QA) are provided in this work. These recommendations highlight the aspects that are most important to consider at each of several key stages (before installation, during installation, and after rehabilitation work is completed).

    Results from comparative life-cycle assessment (LCA) showed that alternative technologies, including cured-in-place (flexible sleeve) and coating techniques, have some advantages over pipe replacement from an environmental perspective. However, the choice to use one rehabilitation technology over another is a multi-stage decision-making process that should not be based solely on a single factor.

    This PhD work promotes an improved understanding of the limitations and benefits of polymeric lining through the testing performed and analyses conducted. This work highlights the need for improved quality control, and further suggests that developing a detailed and comprehensive quality control plan for each technology would provide higher and more consistent quality overall. The study also demonstrates that the long-term strength of any rehabilitation work depends on various factors, and that selecting one method over another must be a process based on extensive knowledge and understanding of each rehabilitation technology. No evidence was found to indicate that the materials could not perform well under working conditions if selected and installed appropriately. However, a larger number of field samples with longer in-service time and a more detailed technical history, along with a more extended experimental plan for laboratory investigations based on the results of this PhD work, will allow for the gathering of the data required to answer questions regarding life expectancy with a higher degree of certainty.

  • 5.
    Laurenti, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Frostell, Björn
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Wennersten, Ronald
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Radical systems, eco-innovation and the transition towards sustainability: industrial product design and cultural change2011Conference paper (Other academic)
  • 6.
    Sen, Cong
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Algae Based Carbon Capture and Utilization feasibility study: - initial analysis of carbon capture effect based on Zhoushan case pre-study in China2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This pre-feasibility study was taken out by the co-operation with Zhejiang University, the CEU lab in Zhejiang University is taking researches of the algae based carbon dioxide capture technology, this report mainly aims to evaluate the GHG mitigation effect of this technology and give suggestions.

     

    This study was carried out at Zhejiang University based on the Zhoushan islands waste incineration power plant project, the report presents the initial feasibility study for the algae based carbon capture and utilization technology focus on the carbon footprint and value summary . First the algae based CCU technology was introduced, then by using the life cycle assessment methodology and based on the description of the whole algae based carbon capture utilization process, each process unit was defined, concerning mass balance analysis was made for each unit, according to the mass balance analysis, carbon flow data was obtained for the whole process. In the discussion part, the carbon dioxide capture and avoid amount was analyzed, also the economic value summary for the material input and output was discussed. Concerning general suggestions for the further development and research about the project were given in five sectors: biotechnology, cultivation and harvesting, biomass utilization, substance and energy input, human resource.

     

    The final conclusion is that the algae based carbon capture and utilization technology is not a carbon negative process, but could produce renewable fuels to avoid certain fossil fuels consumption. Lots of technical limitations exist in the study, it needs more work to applied this technology into reality for China. And the profit analysis based on the value summary for the project is optimistic without the consideration of the initial cost. The algae base CCU technology may become a useful alternative for the carbon abatement in China but not the best choice.

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