This chapter investigates the conversion of wastewater into sustainable energy through the use of novel methods such as anaerobic digestion, microbial fuel cells, geothermal desalination, and internet of things (IoT) integration. It underlines the significance of wastewater treatment and energy sustainability, as well as the need for cost-effective solutions. IoT for real-time data collecting, analysis, and control can help with sustainable wastewater treatment and energy generation. Anaerobic digestion generates biogas, whereas microbial fuel cells convert organic molecules into energy. Geothermal desalination provides low-cost energy efficiency. IoT technology enhances performance, lowers energy consumption, and allows for remote monitoring and maintenance, all of which contribute to a more sustainable and resilient future.

Disaster management systems. This introduction explores the role of disaster management technologies, focusing on their evolution, current applications, and future potential, particularly in the context of AI-based solutions.Historically, disaster management relied heavily on manual processes and rudimentary tools for assessment and response. This often resulted in delayed reactions and inadequate resource allocation during emergencies. Geographic Information Systems (GIS), remote sensing, and telecommunications have all played crucial roles in improving situational awareness and enabling faster decision-making.ICT facilitates real-time data sharing among stakeholders, including government agencies, NGOs, and the public. This connectivity enhances coordination and ensures that critical information reaches affected populations promptly. For instance, mobile technology has empowered communities to report incidents and receive alerts, thereby improving early warning systems.Moreover, data analytics has emerged as a key component in disaster management.

Urbanization and energy are intricately linked phenomena that shape the modern world. Urbanization, the process of population migration from rural to urban areas, has accelerated rapidly over the past century, driven by economic opportunities, technological advancements, and societal changes. This demographic shift has profound implications for energy consumption and sustainability. Cities, as the focal points of economic and social activity, are significant consumers of energy. The convergence of urban growth and energy demand underscores a complex nexus that influences environmental, economic, and social dynamics.The growth of urban areas often leads to increased energy needs due to the concentration of infrastructure, industries, transportation, and residential activities. Urban environments are characterized by high density, which necessitates substantial energy for heating, cooling, lighting, and powering various systems.

Nanotechnology is emerging with the biosynthesis of silver nanoparticles which is toxic free and friendly with the environment. Out of all the biosynthesis methods, plant extracts are more predominantly used which is readily available, and it is a least cost method. The plants have secondary metabolites such as phenolic compounds named as flavonoids; tannins are turned to be the reluctant to synthesize silver nanoparticles (AgNPs) from silver nitrate. The plant chosen to synthesize silver nanoparticles is the Hibiscus rosasinensis for the reason of the presence of various biomolecules. The reduction and stabilization process are performed due to the biomolecules. Silver nanoparticles produced from the Hibiscus plant are easier than the conventional method. The formation of nanoparticle of silver is indicated by the maximum absorbance peak at a wavelength of 458 nm obtained from the leaf and the bark extracts. The antimicrobicidal effects on various microbes were examined, and it is proved that bark produced better results.

The advent of new materials offers promising solutions for enhancing energy storage systems, improving energy efficiency, and mitigating environmental impacts. These advanced materials are characterized by their unique properties, which enable them to address the limitations of conventional materials and contribute to innovative technologies in various fields. In the realm of renewable energy, emerging materials are transforming photovoltaic technology. Traditional silicon-based solar cells are being complemented by new materials such as perovskite solar cells, organic photovoltaics, and quantum dots. Perovskite materials, known for their exceptional light absorption and charge transport properties, have demonstrated the potential for high-efficiency, low-cost solar cells with ease of fabrication. Organic photovoltaics, which use organic compounds to convert sunlight into electricity, offer flexibility and lightweight characteristics, making them suitable for a range of applications from wearable electronics to building-integrated photovoltaics.

This shift is not uniform, however, and varies significantly across different regions due to diverse economic, environmental, and policy contexts. In advanced economies like the European Union and the United States, renewable energy adoption is largely driven by robust policy frameworks, technological advancements, and a high degree of public awareness about climate change. For instance, the European Union's Green Deal and the United States' Inflation Reduction Act exemplify ambitious policy commitments aimed at reducing greenhouse gas emissions and accelerating the deployment of renewable technologies. These regions benefit from well-established infrastructure, substantial financial investments, and a relatively high level of technological innovation, which collectively support the integration of renewable energy into existing energy systems. While these regions often have significant untapped renewable resources—such as abundant solar and wind potential—they may encounter barriers such as limited financial resources, and less mature regulatory frameworks.