Professor

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Water is one of the essential elements for human life. When rain falls in the mountains, the water stored in dams is purified, passes through the water supply system and is used in various places, and the used water flows into the sewage system together with rainwater as waste water. In addition, there are various water-related systems, such as maintenance to prevent overflowing of rainfall in the city and maintenance of water pipes. The field of civil engineering is involved in all of these water and sewage systems. My research focuses on the safety and hazard prediction of the water systems that support our lives and livelihoods, with a particular focus on the detection of new coronaviruses in sewage and the prediction of the number of people infected.

Since domestic wastewater, including water from toilets, flows into the sewage system, we have been researching the detection and prediction of the spread of norovirus using the sewage system, and have published data on concentrations in the sewage on our website. Viruses in the excreta of people infected with norovirus flow to sewage treatment plants. By examining the water in sewage treatment plants, it is possible to determine the infection status of the area, so that the data can be used to determine how much norovirus is likely to spread in the future. In fact, there can be a time lag of up to a month between when the norovirus starts circulating in the city and when we, the public, know about an ‘epidemic’, which refers to a situation where a large number of people are infected. During this time, patients visit a hospital and test positive for norovirus, the number of patients is reported to the health department, and the number of cases is determined to be a ‘sign of an epidemic’ based on the increase in the number of patients. However, if we can alert people to wash their hands and disinfect when norovirus actually starts to appear, we may be able to minimise the spread of the number of infected people. This information is currently being used by local authorities, schools and various other facilities.

Is it a matter of course that water comes out when you turn on the tap? In fact, it is said that water pipes laid during Japan's period of rapid economic growth have become decrepit in many parts of the country, and it is not unusual for them to break at any point. For example, in Wakayama Prefecture, an ageing aqueduct collapsed, stopping the water supply to 60,000 households. If this had been anticipated in advance, the damage could have been prevented.

As water pipes are underground, it is not easy to dig them out and inspect or replace them. So we wondered if it would be possible to predict the risk of damage while they are still underground. If the causes leading to deterioration and ageing can be detected and addressed in advance, damage can be prevented. We hypothesise that slight differences in water quality affect the deterioration of water pipes, and we are attempting to make advance predictions by studying the correlation between water quality and water pipe thickness at each water treatment plant. How can water quality be managed across vast dams? For example, we are looking at using information from satellites to detect changes in water quality and prevent algae blooms before they happen. Algae grow somewhere in the dam when the temperature rises in summer and photosynthesis becomes more active, but it is very difficult to remove the effects of algae, so the best way is to prevent them from growing.

Algae blooms are related to changes in water quality and temperature. This can be predicted by inspecting each point of the dam, but it takes a lot of effort to do this across a large dam without missing anything. We are therefore continuing our research into the possibility of detecting changes in water quality and water temperature in dams from satellites, so that we can improve water quality in advance to prevent algae blooms.

Specially Appointed Professor

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Water is the most abundant substance on the earth, the principal constituent of all living things, and a major force constantly shaping the surface of the earth. It is also a key factor in air-conditioning the earth for human existence and in influencing the progress of civilization. Changes in the distribution, circulation, or temperature of the earth’s waters can have far-reaching effects; the ice ages, for instance, were a manifestation of such effects. Changes may be caused by human activities, in particular, since the latter half of the 20th century. People cultivate the soil, irrigate crops, fertilize the land, clear forests, pump groundwater, build dams, dump wastes into rivers and lakes, and do many other constructive or destructive things that affect the circulation and quality of water in nature. Besides, an expanding population and a rapidly growing economy especially in Asia and Africa are hindering sustainability on the globe.

Our studies and challenges have been focused on solving the world water issuers by understanding water circulation, along with the following subjects: (1) Impact assessment on the hydrological change under the changing climate and the land use change at a global and local scale; (2) Mechanism of slope failure and wood debris by torrential rains; (3) Socio-hydrology: trade-offs between urban flood resilience and urbanisation; (4) Numerical study on water pollution in the inundation areas; (5) Long-term heat, vapour and carbon dioxide fluxes observation for an impact assessment on the interaction between land and atmosphere. 

Furthermore, the following inter-/trans-disciplinary research has been focused on achieving local sustainability: (6) Understanding requirements for sustainability of community-based programs; (7) Value-based co-creation of technology and lifestyle for a society based on a virtuous materials cycle.

Associate Professor

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I am working on research and development of wastewater treatment systems that use the power of microorganisms. Although there are calls for the realisation of a sustainable society, including a carbon-neutral one, from the perspective of water use, there are issues such as the fact that wastewater treatment technology in developed countries is very energy-intensive and that in developing countries wastewater treatment technology has not spread sufficiently in the first place due to cost and other reasons. There is also a growing need to recover limited resources from wastewater, and research and development is being conducted to solve these social problems related to the water environment.