New Delhi : Researchers at the Indian Institute of Technology (IIT) Guwahati have developed a cost-effective water treatment technology capable of removing up to 99 per cent of arsenic from contaminated groundwater, offering a promising solution for regions grappling with toxic water supplies.

The newly developed electrocoagulation (EC) system can eliminate contaminants within minutes, making it particularly suitable for rural and semi-urban areas where access to advanced water treatment infrastructure is limited. The findings of the research have been published in the journal Separation and Purification Technology.

Addressing a Widespread Public Health Threat

With rapid industrialisation and urban expansion driving increased dependence on groundwater, arsenic contamination has emerged as a serious public health concern in many parts of the world. Arsenic can enter groundwater naturally through rock formations or through human activities such as mining and agriculture.

According to Prof. Mihir Purkait of the Department of Chemical Engineering at IIT Guwahati, long-term exposure to arsenic can result in severe health complications, including organ damage and cancer. Globally, an estimated 140 million people are exposed to unsafe levels of arsenic in drinking water, with India, Bangladesh and parts of South America among the most affected regions.

“To address this, many conventional methods have been developed. While some have been successful, they are difficult to implement in uncontrolled environments,” Prof. Purkait said. He noted that most existing systems depend on chemical additives, extended treatment times and sophisticated equipment, which limit their practicality in remote or resource-constrained settings.

He further pointed out that conventional methods often generate surplus sludge and involve time- and energy-intensive disposal processes, adding to operational challenges.

A Modified Electrocoagulation Approach

Electrocoagulation offers an alternative treatment method by using an electric current instead of externally added chemicals. In this process, metal ions are released from electrodes placed in the water. These ions bind with arsenic and other contaminants, causing them to clump together into flocs that can be removed through settling or flotation.

“The process is relatively simple to operate and reduces the need for chemical handling,” Prof. Purkait explained.

Traditional EC systems, however, typically use stationary electrodes. Over time, deposits can accumulate on the electrode surface, slowing the process and reducing efficiency.

To overcome these limitations, the IIT Guwahati research team configured a modified EC system featuring a rotating anode and a stationary cathode. The rotation enhances mixing and improves mass transfer, ensuring uniform generation of iron coagulant species that effectively bind arsenic in the water.

“In this process, a controlled electric current dissolves a sacrificial iron electrode, while its rotation improves mixing and mass transfer. This leads to efficient formation of iron coagulant species that attach to arsenic,” Prof. Purkait said.

During treatment, fine gas bubbles generated in the system adhere to arsenic-laden flocs and lift them to the surface, allowing easy separation. The use of rotating iron electrodes significantly improves removal efficiency while maintaining low operational costs.

Lower Capital and Operational Costs

The research team highlighted the economic advantages of the new system compared to conventional water treatment technologies.

For a small community-scale plant with a capacity of 10-50 kilolitres per day, the EC system would typically cost between ?8 lakh and ?15 lakh. In contrast, conventional systems for similar capacities cost between ?12 lakh and ?20 lakh.

At medium-scale capacities of 100-500 kilolitres per day, the EC system is estimated to cost ?30-80 lakh, while reverse osmosis (RO)-based systems often exceed ?1-2 crore.

Operational costs are also lower, as the EC system does not require expensive membranes or frequent chemical dosing. Maintenance is largely limited to periodic electrode replacement. By comparison, membrane-based systems incur high operating expenses due to membrane fouling, frequent replacement needs and energy-intensive processes.

“The developed technology is particularly suitable for rural and semi-urban areas, where affordability, robustness and ease of operation are critical,” Prof. Purkait said.

Next Steps Towards Field Deployment

The research team plans to conduct field trials to assess the system’s long-term performance in real groundwater conditions, particularly in the presence of multiple contaminants such as fluoride and iron.

Discussions are underway with Kakati Engineering Pvt Ltd, based in Sivasagar, Assam, for fabrication and installation of the system. Further steps towards commercialisation will be initiated once suitable funding support is secured.

If successfully deployed at scale, the technology could provide a practical and economical solution to one of the most pressing groundwater contamination challenges affecting millions across India and beyond.