CESC Ltd, the flagship power utility of RPSG group, has received a patent from the Intellectual Property India for innovating a technology in use of bottom ash from coal-based thermal power plants.

Through a series of extensive research, laboratory tests, and field trials conducted by CESC along with Jadavpur University, Kolkata and SDG Consultants, the company has established that the bottom ash, having physical and chemical properties similar to river sand can replace about 25 to 70 per cent of sand in the concrete production, CESC said in a statement.

The ash generated from the thermal power plant are of two types, including fly ash (constituting about 85 per cent of the total ash generated) and bottom ash ( the remaining 15 per cent). Most of the fly ash is currently utilised in cement production, whereas bottom ash is yet to find useful utilisation area.

The bottom ash is disposed to fill lands and construction of road embankments. A vast stretches of land are locked up for this storage or disposal.

The bottom ash usage in concrete production can help reduce cement consumption due to its inherent pozzolonic property, thereby providing substantial savings in raw material costs and reduction in carbon footprint. It will provide a path forward for mass scale value-added and sustainable use of bottom ash in the construction sector.

The CESC findings are the outcome of tests conducted at Jadavpur University, Central Glass Ceramic Research Institute-Kolkata and Geological Survey of India-Kolkata. The laboratory findings were followed up with construction of trial stretches of M-35 road inside CESC’s own 750MW Budge Budge Generating Station at Pujali, West Bengal. The company has already approached various state PWDs, Ministry of Power, NHAI and leading construction houses for support and adoption of this novel technology, the release said.

“The innovation provides immense opportunity for the power sector and construction industry in terms of environment protection, cyclic reuse of bottom ash and protecting the national river ecology,” Rabi Chowdhury, MD-Generation, CESC said in the statement.

He further emphasised that this technology is developed in line with the company’s commitment to environment and is expected to mitigate the critical existing issues of ash utilisation.

According to Prof Partha Ghosh of Jadavpur University, the research, leading to a government patent, has identified some differentiating characteristics of bottom ash, making it a useful substitute of sand in concrete production

“Use of Bottom ash against existing alternatives to natural sand viz crushed sand, manufactured sand, mine-overburden will enable Indian thermal power plants to reduce carbon-footprint,” he said.

Apart from providing a realistic avenue for mass scale utilisation of thermal power plant ash, this technology will support environment protection and reduce sand mining from river beds, the release said.