Program: Collaborative Research Program for Alumni (CRA)
Field: Geological and Geo-Resource Engineering
Principal Investigator: Dr. Bunchoeun PICH
Sending University: Institute of Technology of Cambodia (ITC)
Japanese Co-Investigator: Prof. Dr. Tsutomu SATO
Japanese University: Hokkaido University
Cambodian soils were found dominated in some clay minerals; however, their applications in arsenic removal from groundwaters in affected provinces of Cambodia have not yet been investigated. This study aimed to focus on possible applications of Cambodian clayey soil for arsenic removal from natural groundwater by study of discontinuous and continuous adsorption. The results of soil characteristics showed that Cambodian clayey soil was composed of quartz (sand, Si-dominated mineral), kaolinite and illite (clay, Al-dominated mineral), and goethite (Fe-dominated mineral). Under optimized condition of 100 g/L, 7 h and 150 rpm, Cambodian clayey soil could reduce groundwater arsenic from initial concentration of 1,072 g/L to a level below the Cambodian guideline of 50 g/L, being 99% for arsenic removal efficiency. Continuous flow experiment indicated that after 7 h at average flow rates of 0.24“0.26 ml/min, Cambodian clayey soil at bed depths of 7 cm and 10 cm in column could produce arsenic-safe water of 360 ml for 15 h and 300 ml for 7 h, respectively before it lost its capacity and started to gradually exhaust/saturate. Therefore, locally-available Cambodian clayey soils should be considered as an alternative for treatment of arsenic-containing groundwaters in affected areas of Cambodia. Treatment of clayey soils by heating, acidification or iron-coating should be also considered in future work for high productivity of arsenic-safe groundwater. I was performing part of research in Hokkaido University in February, 2016. Memorial of understanding between ITC and Hokkaido University for staff exchange is in process for agreement. Prof. Sato and Prof. Yoneda give special lectures on topic of research for better understanding to my students participating in the project. Memorial of understanding between ITC and Hokkaido University for student exchange is in process for agreement. To the society, people at local residence can obtain safearsenic tubewell or dugwell waters for drinking during dry season when available sources of water are limited. To the industry, superficial clayey soil at dominant location of Cambodia can be used as a useful material in treatment system for arseniccontaminated tubewell or dugwell waters.