IIT Guwahati : System to Remove 99% Arsenic from Groundwater
GG News Bureau
Assam ,Guwahati 12th February :Researchers at the Indian Institute of Technology (IIT) Guwahati have developed a new low-cost electrocoagulation-based water treatment technology capable of removing up to 99 % arsenic from contaminated groundwater, offering a potentially transformative solution for affected communities in India and other arsenic-impacted regions of the world.
Groundwater arsenic contamination is a serious public health issue globally, with an estimated 140 million people exposed to unsafe arsenic levels in countries such as India and Bangladesh. Arsenic, a toxic metalloid commonly released from natural rock deposits and human activities like mining and agriculture, can cause conditions including organ damage and cancer upon long-term exposure.
The newly developed technology centres on an electrocoagulation (EC) system, which uses electric current to induce the release of metal ions from iron electrodes placed in the water. These metal ions attach to arsenic and other contaminants, causing them to aggregate into flocs that can then be removed through settling or flotation. This approach avoids the need for external chemical additives and simplifies operation.
A major innovation in the IIT Guwahati design is the incorporation of a rotating anode alongside a stationary cathode. This rotating electrode enhances mixing and mass transfer, leading to more uniform generation of iron coagulant species that effectively bind with arsenic. Simultaneously, fine gas bubbles produced during electrocoagulation attach to arsenic-enriched flocs and lift them to the surface, facilitating their removal.
According to Professor Mihir Purkait from the Department of Chemical Engineering, the system removes contaminants within minutes and is simpler to operate than conventional arsenic treatment technologies, which often require complex infrastructure, lengthy treatment periods, and chemical handling.
Cost comparisons underline the affordability of this technology: for a small community-scale plant (10–50 kilolitres per day), the electrocoagulation system costs about ₹8–15 lakh, compared with ₹12–20 lakh for traditional systems. At a medium-scale (100–500 kilolitres per day), the EC system is priced between ₹30–80 lakh, while reverse osmosis-based alternatives can exceed ₹1–2 crore. Moreover, maintenance is largely limited to electrode replacement, avoiding high operating costs linked to frequent chemical dosing or membrane fouling in other systems.
The IIT Guwahati team plans to conduct field trials in real groundwater conditions and evaluate the system’s performance where other contaminants like fluoride and iron co-exist. They are also in discussions with Kakati Engineering Pvt Ltd of Sivasagar, Assam for system fabrication and installation, paving the way toward wider deployment upon securing funding.
