Rourkela: Researchers at the National Institute of Technology (NIT), Rourkela, have developed a new nature-based wastewater treatment system that could help revive traditional dhobi ghats and reduce pollution in urban water bodies.

Dhobi ghats remain an important source of livelihood in many Indian cities. But shrinking water availability and the widespread discharge of untreated laundry wastewater have created serious environmental challenges. Detergents, dyes and microfibres often end up in rivers and lakes, worsening water scarcity and damaging aquatic ecosystems.

To tackle this, a team at NIT Rourkela has designed a low-cost and chemical-free solution known as the Constructed Wetland-Microbial Fuel Cell system. The setup combines wetland plants, filtration layers and electricity-generating microorganisms to clean laundry wastewater without relying on external energy.

Here's what researchers say

Kasturi Dutta, Associate Professor in the Department of Biotechnology and Medical Engineering, said the system draws inspiration from natural processes. She explained that gravel, sand, soil, plants and microbes work together to purify the water. The added ability to generate bioelectricity opens new possibilities for decentralised wastewater management.

Researchers say the model is affordable, requires little maintenance and can be scaled for use in urban slums, peri-urban communities and rural laundry centres. Its capacity grows as more units are added, making it suitable for large dhobi ghats such as those in Mumbai’s Mahalaxmi and Bengaluru’s Halasuru.

Dutta said the treated water can be reused by washermen, reducing pressure on freshwater sources while also preventing chemical contamination of local lakes and drains.

System installed at NIT Rourkela’s dhobi ghat

As a pilot initiative, the team installed the system at NIT Rourkela’s own dhobi ghat, which produces nearly 1400 litres of detergent-heavy wastewater each day. Tests showed that the setup successfully removed surfactants and reduced chemical oxygen demand to levels permitted by the Bureau of Indian Standards.

The model includes two cylindrical constructed wetland units linked to a microbial fuel cell. Each cylinder contains layers of gravel in different sizes, topped with sand and soil. Graphite chunks placed at the bottom and top act as the anode and cathode.

Wastewater from the dhobi ghat is first collected in an overhead tank and then directed into the system. After passing through the treatment stages, the water emerges clean, free of odour and suitable for reuse in washing.