As a new and rapidly growing science, the applications of ultrasound methods in environmental technology hold a promising future. Compared to conventional methods, ultrasonication can bring several benefits such as being environmentally friendly (no toxic chemical are used or produced), low cost, and compact, allowing on-site treatment. Besides an overview featuring the background behind ultrasonic technology, this brief summarizes the main studies and innovations reported in recent research that has utilized ultrasound methods in environmental analysis, water, and sludge treatment, soil and sediment remediation to air purification.

The future of our world is the future of cities. Therefore, building a holistic guiding framework for urban sustainability, which can be used in urban governance, decision-making, capacity building, education and public awareness raising is a critical key for a sustainable future. The thesis uses visionary and holistic approach in dealing with urban issues. What makes a livable and sustainable city? How do people perceive urban sustainability? How do people envision their dream cities? Among many aspects of urban development, what matter most to them? What are public perceptions on current urban development in HCMC? This thesis seeks to find answers for these questions, from suggestions of experts and think tanks, to people's opinions, their hopes and dreams. Beside the international document research and the global online survey, the case of public perception in Ho Chi Minh City was also investigated with both online and offline questionnaires and interviews of people in some slum areas.