| 1. |
- Wu, Xue, 1986, et al.
(författare)
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Ammonium recovery from reject water combined with hydrogen production in a bioelectrochemical reactor
- 2013
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 146, s. 530-536
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a bioelectrochemical reactor was investigated for simultaneous hydrogen production and ammonium recovery from reject water, which is an ammonium-rich side-stream produced from sludge treatment processes at wastewater treatment plants. In the anode chamber of the reactor, microorganisms converted organic material into electrical current. The electrical current was used to generate hydrogen gas at the cathode with 96±6% efficiency. Real or synthetic reject water was fed to the cathode chamber where proton reduction into hydrogen gas resulted in a pH increase which led to ammonium being converted into volatile ammonia. The ammonia could be stripped from the solution and recovered in acid. Overall, ammonium recovery efficiencies reached 94% with synthetic reject water and 79% with real reject water. This process could potentially be used to make wastewater treatment plants more resource-efficient and further research is warranted.
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| 2. |
- Munthe, Christian, 1962
(författare)
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Precaution and Ethics: Handling risks, uncertainties and knowledge gaps in the regulation of new biotechnologies
- 2017
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This volume outlines and analyses ethical issues actualized by applying a precautionary approach to the regulation of new biotechnologies. It presents a novel way of categorizing and comparing biotechnologies from a precautionary standpoint. Based on this, it addresses underlying philosophical problems regarding the ethical assessment of decision-making under uncertainty and ignorance, and discusses how risks and possible benefits of such technologies should be balanced from an ethical standpoint. It argues on conceptual and ethical grounds for a technology neutral regulation as well as for a regulation that not only checks new technologies but also requires old, inferior ones to be phased out. It demonstrates how difficult ethical issues regarding the extent and ambition of precautionary policies need to be handled by such a regulation, and presents an overarching framework for doing so.
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| 3. |
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| 4. |
- Mårtensson, Lennart, 1957-, et al.
(författare)
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Biomass from wetlands and other valuable conservation areas as substrate for industrial biotechnology
- 2016
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Ingår i: The Ninth International Conference on the Establishment of Cooperation between Companies and Institutions in the Nordic Countries, the Baltic Sea Region, and the World. - 9789188357410
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Konferensbidrag (refereegranskat)abstract
- Biomass from wetlands has historically been an important resource, but today it is difficult to take advantage of this biomass, besides being used as feed on the farm. A very important goal is to find rational and economical viable way to make biogas from wetland biomass, including biomass from other conservation worthy areas of high biodiversity, such as roadsides harvested frequently. Moreover, the residues from biogas process used as bio-fertilizer to the fields, so that nitrogen and phosphorus is returned to the farm land. The biomass can be used for the production of biogas or for extracting valuable chemicals in bio refineries. These valuable chemicals may be potentially useful for making future plastic materials, i.e. bio plastics. Major focus will be on biogas technology, and above all, methods for the pretreatment of recalcitrant substrates such as biomass containing high levels of lignocelluloses, i.e., to make the material available to the biogas-producing bacteria. The work is based on an involvement of research in the areas of environmental engineering and landscape science and includes studies of biodiversity and water treatment function of the landscape. Finally, it is important to stress that mowing of wet meadows mostly will result in a better capacity of such meadows to retain nutrients from water passing through them. Wetland with wet meadows and similar vegetation types will be more efficient in cleaning water and thereby fight eutrophication in the recipient. Summing up, the main advantages using harvest hay (mowing) from wet meadows and roadside meadows as substrate for biotechnical industry are:•Raw material for bio plastics•Cheap and easy handled fertilizers to agriculture•Important for biodiversity•Better function of wetlands as nutrient traps fighting eutrophication of the sea
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| 5. |
- Soam, Shveta, 1987-, et al.
(författare)
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Life cycle assessment of rice straw utilization practices in India
- 2017
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 228, s. 89-98
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to find potential utilization practice of rice straw in India from an environmental perspective. Life cycle assessment (LCA) is conducted for four most realistic utilization practices of straw including: (1) incorporation into the field as fertilizer (2) animal fodder (3) electricity (4) biogas. The results show that processing of 1 ton straw to electricity and biogas resulted in net reduction of 1471 and 1023 kg CO2 eq., 15.0 and 3.4 kg SO2 eq. and 6.7 and 7.1 kg C2H6 eq. emissions in global warming, acidification and photochemical oxidation creation potential respectively. Electricity production from straw replaces the coal based electricity and resulted in benefits in most of the environmental impacts whereas use as an animal fodder resulted in eutrophication benefits. The burning of straw is a harmful practice of managing straw in India which can be avoided by utilizing straw for bioenergy.
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| 6. |
- Hai, Faisal Ibney, et al.
(författare)
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Application of membrane technology for the development of sustainable biotechnology processes
- 2013
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Ingår i: Membrane Processes for Sustainable Growth. ; , s. 193-224
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The scope of application of membranes in biotechnology has widened significantly in the recent years. Although many of the membrane options are yet to achieve wide industrial applications, they show tremendous potential for the transformation and synthesis of value-added products, energy production, therapeutic applications and environmental remediation. This chapter provides an overview of membrane applications in selected established and emerging biotechnology processes. Approaches to overcoming the technology bottlenecks that impede the scale-up of such systems have been discussed in this chapter.
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| 7. |
- Hai, Faisal Ibney, et al.
(författare)
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Biocatalytic membrane reactors for the removal of recalcitrant and emerging pollutants from wastewater
- 2013
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Ingår i: Handbook of Membrane Reactors Volume 2: Reactor types and industrial applications. - : Elsevier. ; , s. 763-807
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The potential fields of application of the biocatalytic membrane reactors have widened considerably in the recent years. Although biocatalytic membrane reactors, in general, are yet to achieve broad industrial applications, in the not too far future, they are expected to play a major role not only for the production, transformation and valorization of raw materials but also for environmental remediations. This chapter comprehensively reviews the laboratory scale studies which demonstrate the potential of biocatalytic membrane reactors in wastewater treatment applications. Studies reported in the literature, however, serves as proof of concept only. Issues that need to be addressed in order to achieve scale-up of such systems have been discussed in this chapter.
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| 8. |
- Kharazmi, Parastou, 1977-
(författare)
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Evaluation of Innovative Rehabilitation Technologies Utilising Polymer Composites for Aging Sewer Systems
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 9. |
- Modin, Oskar, 1980
(författare)
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A mathematical model of aerobic methane oxidation coupled to denitrification
- 2018
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Ingår i: Environmental Technology (United Kingdom). - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 39:9, s. 1217-1225
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Tidskriftsartikel (refereegranskat)abstract
- Aerobic methanotrophic bacteria use methane as their only source of energy and carbon. They release organic compounds that can serve as electron donors for co-existing denitrifiers. This interaction between methanotrophs and denitrifiers is known to contribute to nitrogen losses in natural environments and has also been exploited by researchers for denitrification of nitrate-contaminated wastewater. The purpose of this study was to develop a mathematical model describing aerobic methane oxidation coupled to denitrification in suspended-growth reactors. The model considered the activities of three microbial groups: aerobic methanotrophs, facultative methylotrophs, and facultative heterotrophs. The model was tested against data from the scientific literature and used to explore the effects of the oxygen mass transfer coefficient, the solids retention time, and the fraction methane in the feed gas on nitrate removal. The fraction of methane in the feed gas was found to be critical for the nitrate removal rate. A value of about 15% in air was optimal. A lower methane fraction led to excess oxygen, which was detrimental for denitrification. A higher fraction led to oxygen-limitation, which restricted the growth rate of methanotrophs in the reactor.
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| 10. |
- Modin, Oskar, 1980, et al.
(författare)
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Hill-based dissimilarity indices and null models for analysis of microbial community assembly
- 2020
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Ingår i: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundHigh-throughput amplicon sequencing of marker genes, such as the 16S rRNA gene in Bacteria and Archaea, provides a wealth of information about the composition of microbial communities. To quantify differences between samples and draw conclusions about factors affecting community assembly, dissimilarity indices are typically used. However, results are subject to several biases, and data interpretation can be challenging. The Jaccard and Bray-Curtis indices, which are often used to quantify taxonomic dissimilarity, are not necessarily the most logical choices. Instead, we argue that Hill-based indices, which make it possible to systematically investigate the impact of relative abundance on dissimilarity, should be used for robust analysis of data. In combination with a null model, mechanisms of microbial community assembly can be analyzed. Here, we also introduce a new software, qdiv, which enables rapid calculations of Hill-based dissimilarity indices in combination with null models.ResultsUsing amplicon sequencing data from two experimental systems, aerobic granular sludge (AGS) reactors and microbial fuel cells (MFC), we show that the choice of dissimilarity index can have considerable impact on results and conclusions. High dissimilarity between replicates because of random sampling effects make incidence-based indices less suited for identifying differences between groups of samples. Determining a consensus table based on count tables generated with different bioinformatic pipelines reduced the number of low-abundant, potentially spurious amplicon sequence variants (ASVs) in the data sets, which led to lower dissimilarity between replicates. Analysis with a combination of Hill-based indices and a null model allowed us to show that different ecological mechanisms acted on different fractions of the microbial communities in the experimental systems.ConclusionsHill-based indices provide a rational framework for analysis of dissimilarity between microbial community samples. In combination with a null model, the effects of deterministic and stochastic community assembly factors on taxa of different relative abundances can be systematically investigated. Calculations of Hill-based dissimilarity indices in combination with a null model can be done in qdiv, which is freely available as a Python package (https://github.com/omvatten/qdiv). In qdiv, a consensus table can also be determined from several count tables generated with different bioinformatic pipelines.
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