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Senast publicerade

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    Pharmaceutical Residues in Drinking Water - A Case Study on Pharmaceutical Concentration in Rådasjön and Its Impact on Human and Environmental Health
    (2026) Saadeddin , Nour; Taleb Attar , Mohamad
    In recent years, the occurrence of anthropogenic persistent substances, such as pharmaceuticals, in aquatic environments has attracted global attention to find solutions that both mitigate measured concentrations and address the significant challenges they pose to public health and aquatic ecosystems. This study aimed to identify and quantify pharmaceuticals in Lake Rådasjön, western Sweden, which act as a primary drinking water source for Mölndal’s inhabitants. The study identified metformin (MET) and gabapentin (GBP) as the main pharmaceuticals in the lake water using Liquid Chromatography-Mass Spectrometry (LC-MS) analytical method. The analysis showed that only MET was detected at high concentrations in the drinking water treatment plant (DWTP) effluent, while GBP was below the detection limit, indicating that the current treatment methods at Mölndal's DWTP achieved high removal efficiency. MET, on the other hand, remained high, indicating that current treatment processes were insufficient and other advanced processes needed to be adapted. This thesis was based on a literature review evaluating several treatment methods, followed by laboratory experiments aimed at estimating the removal efficiency of multiple treatment combinations, including ozonation alone, the combination of ozonation and chlorination, and ozonation combined with Granular Activated Carbon (GAC). The results showed that ozonation alone reduced MET concentrations by 52.5%, while the combination of ozonation and chlorination resulted in a similar reduction of 52.9%. The most effective combination to reduce MET concentration, promote human health, and improve the environment was ozonation followed by GAC, which gave a reduction of up to 88.4%. The calculation of the risk assessment showed that the MET concentration found in DWTP effluent posed no risk to human health. Similarly, the MET concentration in the lake did not pose any risk to fish. However, GBP posed a moderate risk to fish and potentially caused oxidative damage. Finally, further research is necessary to better understand the impacts and risks of GBP and MET and to ensure safe water quality.
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    Experimental Security Evaluation of the Tillitis TKey Authentication Ecosystem
    (2026) Eidstedt, Josef; Ekerstedt, William; Farias, Nadia; Houltz, Jonas; Khaniporshokouh, Tiam; Skepö, Emelie
    In this project, a structured security evaluation of TKey-based authentication systems was conducted using an ethical hacking methodology, consisting of reconnaissance, scanning, vulnerability assessment, exploitation, and exploit testing. The results showed that while TKey mitigates several weaknesses of password-based systems, insecure software implementations can still introduce serious vulnerabilities, such as insecure communication, information disclosure, and flaws in authentication logic. Overall, the study demonstrated that security depends not only on the technology itself but also on its design and implementation, highlighting the need for continuous security evaluation across all system layers.
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    Economic Burdens of PFAS in Residual Streams from Drinking Water Treatment
    (2026) Alhitta, Amna H M
    Per- and polyfluoroalkyl substances (PFAS) are highly persistent environmental pollutants linked to adverse health effects, with drinking water serving as a primary human exposure route. While previous studies often focus on treatment efficiency and operational costs of PFAS removal, the economic burdens of PFAS transferred to residual streams generated within drinking water treatment processes remain understudied. This study develops a conceptual framework to investigate the fate of PFAS compounds transferred into residual streams and to assess the associated economic impacts. Considering both local recirculation into raw water systems and release into surrounding aquatic environments, the framework was applied to three Swedish drinking water treatment plants with distinct hydrological conditions. The results demonstrate that hydrological conditions heavily dictate PFAS transport pathways. Closed hydrological systems exhibit high recycling rates and dominant local recirculation costs. In contrast, open systems show limited recirculation but significant downstream transport, resulting in substantial environmental burden costs. Sensitivity analysis revealed that water residence time and time horizon significantly impact these patterns, while higher recipient removal efficiency reduces environmental costs. Conversely, increasing the number of recipient GAC filter units elevates environmental costs. Furthermore, even small annual PFAS masses can generate substantial downstream treatment burdens due to the high cost of removing diluted pollution. Ultimately, the study highlights the necessity of source-oriented management strategies, showing that minimizing PFAS transfer to residual streams is critical to reducing future environmental disadvantages and costly downstream treatment.
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    Experimental Security Evaluation of the Tillitis TKey Authentication Ecosystem - Design and Implementation of a Testing Environment for Security Evaluation
    (2026) Bredberg, William; Glantz, Maximilian; Hakeröd, Erik; Johansson, Elias; Larsson, Hannah; Tarkowska, Zuzanna
    This thesis evaluates the security of the Tillitis TKey authentication ecosystem through simulated attack scenarios and experimental security analysis. Hardware based authentication tokens such as the TKey are an important part of passwordless systems, which aim to replace traditional passwords and improve security. To perform the evaluation, a controlled test environment was developed using virtual machines. Several representative attack scenarios were implemented, including person-in-the-middle, replay, injection, fuzzing, and nonce-reuse attacks. These attacks were used to evaluate security properties such as confidentiality, integrity, and authentication strength, based on observed system behavior and collected log data. The results show that the TKey’s authentication mechanism appears resistant to replay and nonce reuse attacks under the tested conditions, and no direct com promise was achieved through injection or fuzzing. However, the person-in-the middle attack showed that unencrypted communication channels expose authentication metadata and protocol information to interception. The findings highlight that the security of the TKey ecosystem depends not only on the hardware token itself, but also on the security of the surrounding communication and application layers. This thesis contributes a reproducible testing environment and a practical approach for evaluating authentication system security.