Purification of arsenic contaminated water

In India, providing safe drinking water to all is one of the biggest challenge. Sometimes people walk miles to collect safe drinking water, but still they are unable to find it, because of harmful contaminants found in the ground water. Arsenic contamination is one of the prime examples in this part of the country.
Arsenic contamination in drinking water if not detected is a silent killer. With every glass, there is increase in arsenic level in the body and with progressing time it reaches the poisoning level and disease symptoms starts to appear. Arsenic poisoning affects the human body in various ways. An arsenic affected man loses his stamina to work. It makes sore in the skin of palm, leg and back. Sometimes it may cause skin cancer. Long-term poisoning may also cause death.

There are few conventional way of removing Arsenic from the water. But the most efficient method is using reagent called Hybrid Ion Exchanger (HIX), developed by Dr. Arup Kumar Sengupta, Professor at Leigh University, Pennsylvania, USA. The beads are porous and are covered with zirconium-oxide (ZrO2). The arsenic is accumulated in the pores and only the fresh water passes through the HIX beads.
We took our students to Arsenic removal plant at Binimaypara, Ashoknagar

Our students wanted to solve this problem by using innovative automated method where without any human intervention we can check whether HIX beads are saturated with arsenic or not. For this, they tried to use Lego Mindstorms sensors like ultrasonic, IR sensors, color sensors. But with the sensors of Lego Mindstorms they were unable to detect any difference between fresh HIX beads and saturated HIX beads. Then we suggested them to use Arduino Moisture sensor and they found there is a conductivity difference between fresh HIX beads and saturated HIX beads, the conductivity of fresh HIX beads is greater than the saturated HIX beads.