Microbubble technology dramatically raises the efficiency of the flotation and aeration processes of water treatment plants (WTPs), which see extensive use in developed countries. A local institution, Indonesia Water Institute, has tried to investigate microbubble technology intended for lab-scale WTP. However, the current reactor system does not yet meet the microbubble criteria, especially as it has had few investigations of its abilities in flotation and aeration. This study aims to analyze the effect of size variations that affect the rising velocity and mass transfer coefficient (kLa) of aeration contact time. Three local spargers were used to produce microbubbles. Bubble diameters were measured optically and analyzed using ImageJ software. The dissolved oxygen (DO) concentration was measured every minute using an automated sensor so that the kLa could be determined. Of the three spargers, the smallest bubble size was produced by the vortex type with an average bubble diameter of 89 μm and the slowest rising velocity of 17.67 m/h. It also yielded the highest kLa of 0.297/min, which gave an aeration contact time of 3.64 minutes. The experimental uses of three local spargers revealed that the smaller the microbubble diameter, the higher the mass transfer coefficient in flotation and aeration processes. This research can be the basis for developing microbubble technology for WTP in Indonesia.

Waters provide essential needs both for human societies as well as natural ecosystems. Floating solar PV (FPV) applications on water bodies are currently in strong demand worldwide. Floating solar PV system is a new concept in renewable energy with the solar plants by harnessing available water...

This note is presented as continuance discussion in previous edition more focus on how Higher Education Institutions (HEIs) contribute to create sustainable universities, sustainable future. As we know that university is an institution of higher education and research which awards academic degrees in various academic disciplines. Generally, it provides undergraduate education and postgraduate education involved large numbers of students, academic and non-academic staffs also wide areas of buildings. Hence, universities can be considered as “small cities” (Alshuwaikhat & Abubakar, 2008) whereas their massive daily activities in term of teaching, research, and community engagement, also movement of goods and persons inside and outside campuses have contributed greenhouse gases emission. We can see that universities have different type, function, size and buildings complexity, energy and electricity consumption, waste generation, water and materials consumption, public transportation, education activities and so forth so that obviously, they brought significant impacts on the environment within their boundaries. In regards to these facts, since the last two decades’ discussion on campuses’ externalities on environmental quality and integrity is profound and rise the need to consider sustainability in academic institutions.Many universities in developed countries have aware on this environmental issue, and take a lead in initiating and implementing policies on green and sustainability campus. For example, in US and UK where the greatest number of universities had actively involved in all aspects of sustainability (Puertas & Marti, 2019). Several Irish Universities set their policies on sustainability by referring to Education for Sustainable Development (ESD), a document produced by the Irish government that explicitly targets as National Strategy on Education for Sustainable Development in Ireland 2014-2020 (Shawe et al., 2019). Numbers of local and global association that strongly commit and put serious concern in sustainability issue such as Global Universities Partnership on Environment for Sustainability (GUPES), Sustainable Development Solutions Network (SDSN), International Sustainable Campus Network (ISCN), Association for the Advancement of Sustainability in Higher Education (AASHE), Sustainability University Network (SUN) Thailand, Campus Sustainability Network in Japan (CAS-Net Japan) etc. have been established and significantly growth in number of participating university. Furthermore, as the UNDP 17 SDGs became widely global concern including the role of HEIs in achieving SDG targets by 2030, many more universities become aware regarding the implementation of sustainability efforts and their annual report on sustainability which related to SDGs. To appreciate and acknowledge universities who have strong commitment and works hard on campus sustainable efforts, UI GreenMetric World University Rankings was developed in 2010 as a tool to support green universities development (Suwartha & Riri, 2013). The ranking has 6 categories to be evaluated: firstly, the university landscape (setting and infrastructure), secondly the electricity consumption (energy and climate change), the third is waste management, the forth is water preservation, the fifth is green transportation for public, and the last is education and research that related to sustainability. From these 6 categories, some goals of the 17 SDGs are relevant such as goals 9 and 11 for category setting and infrastructure, goals 7, 12, and 13 for category energy and climate change, goals 3, 12, and 14 for category waste management, goal 6 for category water preservation, goals 13 and 15 for category green transportation, and goal 4 for category education and research. In 2018, 719 universities from 81 countries have participated in the rankings and have significantly changed their attitudes towards sustainability challenges in their own contexts. Having this large numbers of participants in global scale, UI GreenMetric World University Rankings Network (UIGWURN) was established in 2017 to be a platform for sharing best practices and encourage more universities to put sustainability agenda as one of their priorities. Currently, there are 29 country-based coordinators for the UIGWURN. The network has three main thematic priority activities: (1) Shaping Global Higher Education and Research in Sustainability; (2) Creating Global Sustainability Leaders; and (3) Partnering on Solutions to Sustainability Challenges.Significant impact of the UI GreenMetric ranking shown by the increasing number of participants, covered in dynamic regions of North America, South America, Europe, Africa, Asia, and Australia and Oceania. Many participating universities through their website express sincere gratitude and proud that their continuous sustainability efforts have been acknowledged by listed in the ranking. Appreciation to UI GreenMetric ranking also given by the International Ranking Expert Group (IREG) as a global sustainable ranking for university. Though several authors gave critical analysis and positive feedback for a green ranking including UI GreenMetric (i.e. Ragazzi & Ghidini, 2017), some authors on contrary proposed a composite indicator developed using data envelopment analysis (DEA) and combined with UI GreenMetric that later known as the DEA-GreenMetric ranking (Puertas & Marti, 2019).Based on the above findings, it can be concluded that UI GreenMetric has been acknowledged globally as the only one sustainability ranking which relevancy simple, accessible, and has significant role as benchmark or guidance tools particularly for universities in developing countries towards creating sustainable universities, sustainable future. Nurturing Research and Technology DevelopmentIn order to hasten developments in all research areas, various improvement of technologies through alternative designs, methods,...