Arsenic removal in Nicaragua

On behalf of the TU Delft, National Water Authority (ANA) and Nuevas Esperanzas, we (Tom Vromen & Joost van Arkel) conducted a research about Arsenic Removal for Drinking Water Treatment in Nicaragua. This research was executed in cooperation with PHD-student Bayardo Gonzalez and Sanitary Engineering Professor Doris van Halem from the TU Delft.

Arsenic is impossible to smell, taste or observe, which makes it very hard to localize. The World Health Organization (WHO) has recommended arsenic level to be less than 10µg As/l for water to be safe for drinking. In some rural communities in Nicaragua, the amount of arsenic exceeds this minimum level. This is due to active volcanoes, which increase the percentage of Arsenic in groundwater.

In the rural community named Nuevo Amanecer, next the to active volcano Telica, citizens are suffering from Arsenic contaminated water. After natural disasters, this community moved to the new location where they are situated now. During the first couple of years, people had to walk several hours to provide themselves with fresh drinking water. Different companies stepped in and decided that a reservoir needed to be built to make life in this area better. After the building of the pump and the reservoir, drinking water is provided for this community. Different measurements showed that the level of Arsenic in this groundwater exceeded the maximum value of 10 µg As/l. A NGO, named Nuevas Esperanzas, built another reservoir. This reservoir was filled due to a clean water spring next to Telica. People are still using water from both reservoirs for drinking because they are not aware of the problems Arsenic can cause. 

To get rid of this problem, we constructed a Nano-filtration treatment plant. This experiment is executed to get clean water out of toxic water with the highest efficiency. In this way, we can give the water Authority of Nicaragua a proper advice in the efficient removal of arsenic compounds. The Nano-filtration plant was powered by solar energy. Therefore, the treatment plant had a low energy-consuming factor and the efficiency remained high.

Once the system was build, our tasks consisted of taking water samples on a daily basis. In total we had four different water flows within the system. Each water flow had their own characteristics. To measure these characteristics we made use of two different measurement devices. The first device we used was HANNA, which is able to describe the general water characteristics. The second measurement device was the Arsenator, which shows the amount of Arsenic in the water. By making use of the test results, we were able to see if the Nano-filtration plant was working. At the end it became clear that we had an Arsenic removal of 99% and the amount of Arsenic in the permeate was <10 µg/l. Therefore we can conclude that the Nano-filtration plant was a success.

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