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Microalgae have emerged as a promising feedstock for biofuels and high-value compounds, offering potential solutions to global energy and resource challenges. This comprehensive review examines the latest advancements in microalgae cultivation technologies, focusing on both open systems and enclosed photobioreactors (PBRs). We analyze various configurations including open raceway ponds, tubular PBRs, flat panel PBRs, and novel designs such as the Light Exchange Bubble-column (LEB). The review encompasses key performance indicators such as biomass productivity, energy efficiency, and water usage, as well as life cycle assessment (LCA) results for different cultivation systems. We also discuss the challenges and opportunities in scaling up microalgae production, the potential for integrating wastewater treatment and CO2 mitigation, and the prospects of biorefinery approaches. By synthesizing recent research findings and identifying knowledge gaps, this review aims to provide a comprehensive understanding of the current state and future directions in sustainable microalgae cultivation for researchers, engineers, and policymakers in the field of renewable energy and biotechnology.

Urban areas face significant environmental challenges, notably rainwater management and the urban heat island effect. As sustainable ecological infrastructures, Green roofs provide dual benefits in addressing these issues. The literature review thoroughly explores how effective green roofs are at boosting urban resilience by mitigating Urban Heat Island effects and enhancing stormwater control. Findings across various studies indicate that green roofs could significantly reduce surface and ambient temperatures, with some studies reporting surface temperature reductions of up to 30 °C. Additionally, green roofs contribute to stormwater management by retaining at lseast 51% of annual rainfall, thereby reducing runoff volume and peak flow rates. By synthesizing data from 28 case studies worldwide, this review highlights the substantial environmental benefits green roofs offer in urban settings. Our analysis suggests that broader implementation and further research into green roof technologies are essential for sustainable urban development. This paper calls for increased integration of green roofs into urban planning to leverage their environmental benefits, particularly in mitigating climate change impacts and enhancing urban ecological systems.