According to Dr. Pham Xuan Su from the Institute of Science and Technology, using conventional oxidation methods combined with sunlight can effectively eliminate impurities, especially arsenic, from groundwater.
Research indicates that arsenic can be absorbed onto the surfaces of granular materials, clay particles, or cellulose-based materials. Therefore, Dr. Su suggests that simply filtering raw water through a medium consisting of sand, activated carbon, and filter cloth can capture contaminants such as mud, clay, organic particles, iron and manganese precipitates, bacteria, and arsenic.
Additionally, introducing air into the water can oxidize the arsenic and iron present. The photochemical oxidation reaction can be further enhanced by adding a few drops of lemon juice or concentrated lime water.
Currently, only about 70% of the population in Hanoi has access to clean water.
