Researchers at the IIT Guwahati have developed a low-cost electrocoagulation-based system that can remove up to 99% arsenic from contaminated groundwater, offering a practical solution for arsenic-affected regions.

What is the new technology?

• The system is based on electrocoagulation, a water-treatment process that uses electric current instead of added chemicals.
• It uses a rotating iron anode and a stationary cathode, which improves mixing and speeds up contaminant removal.
• Arsenic binds with iron particles released from the electrode and is then removed through settling or flotation.

Why arsenic in groundwater is a concern

• Arsenic enters groundwater from natural rock formations and human activities such as mining and agriculture.
• Long-term exposure can cause:
  • Organ damage
  • Skin disorders
  • Cancer
  • Heart disease risk
• Around 140 million people globally are exposed to unsafe arsenic levels, with India and Bangladesh among the worst affected.

Arsenic-affected Regions

• According to the Integrated Management Information System (IMIS), there are about 1,800 arsenic-affected rural habitations in India where 23.98 lakh people are at risk.
• IMIS data indicates that there are 6 arsenic-affected States with regard to ground water sources. 
  • West Bengal (1,218) has the maximum number of habitations having arsenic contaminated water followed by Assam (290), Bihar (66), Uttar Pradesh (39), Karnataka (9) and Punjab (178).
• According to Central Ground Water Board data, 19 districts in Assam have arsenic above 0.01 mg/l: 
  • Sivasagar, Jorhat, Golaghat, Sonitpur, Lakhimpur, Dhemaji, Hailakandi, Karimganj, Cachar, Barpeta, Bongaigaon, Goalpara, Dhubri, Nalbari, Nagaon, Morigaon, Kamrup, Darrang, and Baksa.

Key advantages of the IIT Guwahati system

• High efficiency: Removes 99 % arsenic within minutes.
• Low cost:
  • Small community plants (10–50 kilolitres per day): ₹8–15 lakh
  • Conventional systems: ₹12–20 lakh
• Lower operating cost:
  • No expensive membranes
  • Minimal chemical use
  • Maintenance mainly involves electrode replacement
• Rural-friendly: Simple design, robust operation, and suitable for rural and semi-urban areas.

How it improves existing methods

• Traditional methods:
  • Require chemical dosing
  • Take longer
  • Generate excess sludge
• Rotating electrode system:
  • Prevents deposit build-up
  • Enhances mass transfer
  • Improves overall efficiency

Future roadmap

• Field testing in real groundwater conditions with multiple contaminants such as fluoride and iron.
• Discussions underway with an Assam-based engineering firm for fabrication and installation.
• Commercialisation planned after securing funding.

One-line wrap

The new electrocoagulation system from IIT Guwahati offers an affordable and scalable solution to India’s arsenic-contaminated groundwater crisis.

Exam Hook – 

Q. With reference to electrocoagulation technology for water purification, consider the following statements:

1. It removes contaminants using electric current without adding external chemicals.
2. Rotating electrodes improve efficiency by enhancing mixing and mass transfer.
3. The technology is more expensive than membrane-based reverse osmosis systems.

Which of the statements given above is/are correct?

Answer: 1 and 2 only

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