http://lutpub.lut.fi:80/handle/10024/158302 2026-06-10T09:10:38Z 2026-06-10T09:10:38Z Shahid, Kanwal http://lutpub.lut.fi:80/handle/10024/172315 2026-06-10T08:00:20Z 2026-06-30T00:00:00Z

Simultaneous recovery of energy and nutrients from wastewater using microbial nutrient recovery systems : a self-sustainable process Shahid, Kanwal The discharge of nutrients from wastewater can cause eutrophication in water bodies and deplete valuable nutrient resources. A strategy that treats wastewater while recovering nutrients offers a promising research and development opportunity to address water and nutrient scarcity in an efficient, eco-friendly way. Conventional treatment methods often waste nutrients and energy in wastewater and require large amounts of electricity. Recently, a microbial nutrient recovery cell (MNRC) was developed to use the energy in wastewater to treat it while simultaneously recovering nutrients. The innovation of this PhD thesis lies in developing efficient electrodes (both anodes and cathodes) through a simple and scalable functionalization method that can inspire further research. This work extensively examines key factors such as electrode material, microbial cell volume, wastewater composition, and the effect of ion exchange membranes on nutrient recovery, chemical oxygen demand (COD) reduction, and net energy production. The primary goal of the research was to develop a highly efficient microbial nutrient recovery system that selectively recovers ammonium and phosphate from the source. Various materials including carbon cloth, carbon brush, chitosan beads, activated carbon, stainless steel, and hybrids of chitosan and activated carbon were used to construct cathodes and anodes in microbial fuel cells which were thoroughly analyzed to establish their energy output, COD reduction, and microbial community growth and characterization. The work aimed to identify high-performance anode electrode materials that demonstrate enhanced nutrient selectivity and recovery. Due to the desired properties identified in the studies that comprise this thesis, carbonaceous materials such as graphite rods and brushes, carbon cloth, carbon felt, and activated carbon are widely used as electrodes in microbial fuel cells (MFCs) . Selected electrodes were modified to understand the effect of modification on energy production and nutrient recovery in the MNRC process. For this purpose, surface modification, heat treatment, and the formation of hybrid composites were examined. The work investigates the performance of electrodes in the MNRC system in terms of COD reduction of the waste stream up to 98%, the selectivity of valuable nutrients, concentration in the recovery compartment up to 80% of phosphate for carbon brush as anode electrode, energy production as a function of time (recovery cycles up to 10), initial nutrient concentrations of 10ppm used in wastewater. In case of hybrid anode electrode containing equal volume of activated carbon and chitosan in microbial nutrient recovery system with the total COD load of 718 mg/L, a total COD removal of up to 79% was reached after 10 operation cycles.

2026-06-30T00:00:00Z Ramaul, Laavanya http://lutpub.lut.fi:80/handle/10024/172293 2026-06-09T08:00:24Z 2026-06-26T00:00:00Z

Rethinking AI in organizations : assumptions, affordances and architectures Ramaul, Laavanya This dissertation examines how the adoption of Generative AI, particularly large language model tools such as ChatGPT, reshapes human–AI relations in knowledge-intensive work and the implications for organizational practices and business models. While earlier AI systems focused on automation, prediction, and structured decision support, Generative AI introduces distinct capabilities in content creation, analysis, and interactive collaboration. Despite its rapid diffusion across industries, existing research remains fragmented and often relies on implicit assumptions that portray AI as either perfectly rational or human-like, obscuring how its organizational role is shaped by context, social relations, and the ways it is enacted in practice. To address these gaps, the study combines three methodologically complementary approaches: a problematizing literature review, semi-structured interviews with 29 professionals across knowledge-intensive industries, and a multiple-case study of eight organizations. Drawing on agency and relational perspectives, affordance theory, and business model innovation, the dissertation connects conceptual assumptions about AI with the practical capabilities Generative AI provides in knowledge work and the organizational outcomes that follow. The findings yield three interrelated contributions. First, prevailing assumptions of rationality and anthropomorphism structure how AI is theorized in organization and management research in ways that risk oversimplifying its organizational role and obscuring its relational and context-dependent nature. Second, Generative AI introduces creational and conversational affordances that evolve through use, reinforcing one another in ways that progressively expand the scope and value of human–AI interaction over time. Third, although Generative AI supports business model innovation, its impact is asymmetric: organizations can more readily enhance internal processes than develop new offerings, and they find it hardest to establish viable revenue models. Collectively, these findings reconceptualize Generative AI as a relational, embedded technology whose organizational consequences emerge through ongoing human–AI interaction, thereby advancing organization and management theory with an integrated framework spanning theoretical assumptions, practical capability development, and business model transformation.

2026-06-26T00:00:00Z Komarov, Timofei http://lutpub.lut.fi:80/handle/10024/172212 2026-06-04T07:00:49Z 2026-06-29T00:00:00Z

Compact, energy-efficient electro-hydraulic architectures for multi-actuator control of mobile cranes Komarov, Timofei In mobile machinery, conventional valve-controlled hydraulic systems are characterized by substantial throttling losses, limited energy recuperation, and high power demand. Direct-driven electro-hydraulic actuators represent a more energy-efficient alternative. However, their practical adoption is limited by the need for a dedicated electro-hydraulic converter (EHC) for each cylinder, which increases the system’s size, cost, and complexity. This dissertation addresses the implementation of electro-hydraulic actuation based on centralized or shared EHC architectures without compromising machine usability or productivity. The objective is to formulate and validate compact EHC-sharing actuation principles supported by architecture-aware control algorithms. This research combines the design of actuation system architectures, an analysis of energy losses, dynamic simulations, and laboratory experiments on a log crane PATU 655. Two main approaches are formulated and evaluated. The first approach uses the unidirectional loading of the lift cylinder, enabling its single-chamber direct-driven actuation, while the remaining cylinders are supplied by the same EHC through directional control valves. Laboratory experiments demonstrate a significant reduction in energy consumption, with median savings of 53.83% during log loading and 62.05% during log unloading cycles compared to a reference valve-controlled load-sensing (LS) system without compromising operational productivity. The second approach introduces automatic sequential actuation of crane cylinders using a single EHC by switching connections between them. Experimental results confirm reduced energy consumption, with median savings of 62.6% during log loading and 49.8% during log unloading cycles compared to a reference LS system. The results demonstrate that substantial energy reduction and multi-actuator operation in mobile cranes can be achieved using a single EHC. The identified limitations provide a basis for future research on practical machine implementation and on-field validation.

2026-06-29T00:00:00Z Ibebunjo, Kosisochi http://lutpub.lut.fi:80/handle/10024/172102 2026-05-28T04:30:17Z 2026-06-15T00:00:00Z

3D-printed adsorbents from recycled polymer for urban mining and wastewater treatment Ibebunjo, Kosisochi Tailings and industrial wastewater contain both valuable and harmful metals, representing a combined environmental challenge and resource opportunity. Adsorption is widely applied for metal recovery and contaminant removal. However, many adsorbents are typically available as small particles, which create difficulties such as separation, particle loss and limited reusability. Additionally, the accumulation of polymer waste contributes to environmental pollution. This research investigated the integration of adsorption and three-dimensional (3D) printing using recycled polymers to produce structured adsorbents for metal recovery and contaminant removal from tailings and industrial wastewater. The aim was to reduce environmental pollution from tailings, wastewater and polymer waste while increasing opportunities for water and polymer reuse and the recovery of valuable metals. Three 3D-printed adsorbents containing 10 wt.% lewatit MDS TP220 (3D-LTP), 10 wt.% Fe–Ni bimetallic particles (3D-FeNi) and 30 wt.% cellulose post-functionalised with citric acid (CA/3D-MCC) were fabricated using selective laser sintering (SLS) with pre- and post-printing functionalisation techniques. The respective materials, tailored for selective copper recovery, arsenic removal and heavy metal pollutant removal, were characterised and evaluated for their adsorption performance and reusability. Characterisation confirmed that the SLS process preserved the functional groups and structural features of the functional materials, while the recycled polymers primarily served as structural support. The functional materials were firmly affixed within the polymer matrix, resulting in structurally stable, reusable and easy-to-handle adsorbents. 3D-LTP showed high selectivity for Cu(II) and 90.6% removal. 3D-FeNi achieved 92% and 99% removal of As(III) and As(V), respectively. CA/3D-MCC exhibited 95.7% removal and high selectivity for Pb(II), with performance comparable to the parent material. The findings demonstrate that 3D printing can be effectively utilised to produce mechanically stable, reusable and customisable adsorbents from recycled polymers. The approach supports circular economy principles and offers a promising strategy for simultaneous pollution mitigation and resource recovery from wastewater and tailings.

2026-06-15T00:00:00Z