Fly ash dyke breach in Singrauli points to a bigger problem of fly ash disposal

Two people have died as a result of the breach in the fly ash dyke of Reliance’s Sasan Ultra Mega Power Project in Singrauli

By Soundaram Ramanathan, Ishan Kukreti
Published: Saturday 11 April 2020

This story has been edited to remove the name of a source who doesn’t wish to be named.

Two people died as a result of a breach in the fly ash dyke of Reliance’s Sasan Ultra Mega Power Project in Singrauli, Madhya Pradesh on April 10, 2020.

The toxic slurry spread to an area of six kilometres and also destroyed agricultural fields.

“The breach occurred owing to the negligence of the plant. There are no villages that have been directly affected, and the ash has flown through a channel to the Rihand dam,” Singrauli District Collector KVS Choudary was quoted as saying in media reports. 

However, the incident points to a bigger problem that might impact Thermal Power Stations (TPS) -accumulation of fly ash in the ash dykes in the absence of means to dispose it. 

Around 217 million tonnes of fly ash were generated from 195 Thermal Power Plants (TPPs) in 2018-19, according to a January 2020 Central Electricity Authority’s (CEA) report on fly ash generation from TPPs.

This meant that every day, TPSs generated around 461,284 tonnes of fly ash. Of this amount, around 77 per cent was utilised.

The fly ash is utilised mostly in the cement and building industries including road construction, concrete and bricks manufacturing and filling of low-lying areas. Together, these activities account for around 60 per cent of the fly ash utilisation.

However, all these activities have come to a halt due to the ongoing lockdown, leading to accumulation of fly ash, according to experts. 

“The cement factories are now in lockout due to pandemics since March 25. This means power plants are required to pump more ash into ash ponds,” an official from Hindalco Industries said on conditions of anonymity.

“This sudden accumulation of load and water creates a burden on the ponds. Ash ponds are designed to withstand stress owing to ash retention, they are not designed to withhold hydraulic stress due to excess water in the slurry,” the official added.

Under normal circumstances, TPSs dispose of the fly ash on a daily basis, according to the official. 

Power stations would need to build methods for safely handling and storage of this waste with less water use, and periodically removing water from the ponds, he further added.

To add to the problem is the fact that ash dispersion is the maximum in summer months, before going down during the monsoon. 

Experts say the load on the dyke also depends on other factors.

“It depends on your ash dyke capacity, whether you generate dry or wet ash. But it cannot be denied that if you are unable to dispose of the fly ash, it’ll become a problem,” said a senior official at a private thermal power generator. 

“Central Pollution Control Board and other environmental regulators should advise State Load Dispatch Centre (SLDC) to schedule or allow the plant to operate only when it has room to store fly ash safely,” said Ashu Gupta, former general manager, Environment, National Thermal Power Corporation.

“Otherwise, this can only cause a nuisance in these difficult times. Ideally, power stations should determine their ability at this pandemic juncture to fill ash waste before committing to scheduling their stations to SLDC,” Gupta added. 

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