Deadly Fly Ash

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

Background:

• The Reliance Power's Ultra Mega Power Project's (UMPP) in Sasan area of Singrauli fly ash dyke collapsed.
• The flood of the toxic ash slurry from the collapsed dyke located in adjoining Harhawa village washed away six persons, including three kids, a woman and two men living in the adjoining villages.
• So far two bodies have been retrieved from the ash slurry which has mixed in a nullah and flown to the Rihand Dam around 7 km away on the MP-UP border. Four more persons are missing and feared dead.
• This is not the first fly ash dam collapse of power plants in Singrauli, which is considered the electric power hub of the MP.
• This is the third time such a breach or collapse has happened in the dam/dyke (which stores fly ash remains of coal lighted power plants) of any power plant in Singrauli district.
• In August 2019, a similar breach of ash dyke of the Essar Power Plant in Mahan area had caused major loss of crop and damage to houses in adjoining villages.
• Just two months later a similar incident in NTPC's Shahpur plant had washed away crops and cattle in adjoining villages.

These incidents have exposed the negligence being shown by power generating companies in construction of safe and permanent ash dykes in Singrauli, which is around 700 km from Bhopal.

What is fly ash?

• Fly ash is a byproduct from burning pulverized coal in electric power generating plants.
• Content: Depending on where the coal was mined, coal ash typically contains heavy metals including arsenic, lead, mercury, cadmium, chromium and selenium, as well as aluminum, antimony, barium, beryllium, boron, chlorine, cobalt, manganese, molybdenum, nickel, thallium, vanadium, and zinc.
• During combustion, mineral impurities in the coal (clay, feldspar, quartz, and shale) fuse in suspension and float out of the combustion chamber with the exhaust gases.
• As the fused material rises, it cools and solidifies into spherical glassy particles called fly ash.
• Fly ash is collected from the exhaust gases by electrostatic precipitators or bag filters. The fine powder does resemble portland cement but it is chemically different.
• Fly ash chemically reacts with the byproduct calcium hydroxide released by the chemical reaction between cement and water to form additional cementitious products that improve many desirable properties of concrete.
• All fly ashes exhibit cementitious properties to varying degrees depending on the chemical and physical properties of both the fly ash and cement.
• Compared to cement and water, the chemical reaction between fly ash and calcium hydroxide typically is slower resulting in delayed hardening of the concrete.
• Delayed concrete hardening coupled with the variability of fly ash properties can create significant challenges for the concrete producer and finisher when placing steel-troweled floors.

Fly ash utilization:

• The major sector that utilizes fly ash are buildings and road infrastructure projects. A few highways, flyovers or expressways here or there make for little use of flyash.
• Some power plants in Sonbhadra also use ash to fill up low-lying areas where construction is to occur. But the use here remains limited and sporadic.
• The cement companies are the other big consumers of flyash. In the Pozzolona Portland Cement (ppc) about 25-30 of the content is flyash. 
• Flyash should be used in constructing roads and embankments, large user groups -- like highway authority and the central public works department -- hardly consider using flyash. 
• Currently, 90 million tonnes of flyash is being generated annually in India. 
• 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. 
• According to government and pollution control norms, ash ponds are supposed to be reinforced with concrete walls and should not used beyond their capacity. The artificial ponds store ash, which is the byproduct of coal-fired power plants.

What are the reasons behind such incidents?

• The latest incident has been caused by the serious lapse on the part of the Reliance Power administration and strictest possible action will be initiated in the matter.
• The break in the ash dump yard wall pushed the water leading to break in the boundary wall affecting some thatched houses and minor land parcel.
• This is sheer negligence in implementation of industrial safety norms which took precious lives, and affected livestock, agriculture and environment.
• The incident mirrors seriousness of competent authorities in implementation of orders as they knew about the vulnerability of the condition of ash dike.

Why coal ash is a challenge?

• The coal ash is a "hazardous cocktail" of heavy metals known to cause liver and kidney ailments.
• A 2012 study by India's Centre for Science and Environment found mercury levels in blood samples in the region - home to over 10 coal-fired power plants - to be six times more than what is considered safe.
• The ash in the soil can significantly hit agricultural output for at least two seasons.
• Fly ash particles (a major component of coal ash) can become lodged in the deepest part of your lungs, where they trigger asthma, inflammation and immunological reactions.
  • In addition, respirable crystalline silica in coal ash can also lodge in the lungs and cause silicosis or scarring of lung tissue, which can result in disabling and sometimes fatal lung disease and cancer.
  • Lastly, the presence of heavy metals in coal ash, such as lead, arsenic and hexavalent chromium, and the radioactivity of some ashes may increase the harm caused by inhalation. 
• If eaten, drunk or inhaled, these toxicants can cause cancer and nervous system impacts such as cognitive deficits, developmental delays and behavioral problems.
• They can also cause heart damage, lung disease, respiratory distress, kidney disease, reproductive problems, gastrointestinal illness, birth defects, and impaired bone growth in children.

What about recycling?

• Coal ash recycling poses health risks, especially where the ash is exposed to water: for example
  • when sprinkled as cinders on snowy roads
  • spread as agricultural fertilizer
  • used as a landfill or to fill abandoned mines
• These uses risk leaching into ground water or surface water.

Conclusion:

Generation of fly ash and its unscientific disposal has continued despite such killing incidents. Singrauli comes second in the list of the top ten critically polluted industrial clusters of the country, a ranking in which Ghaziabad district of UP occupies the first position, owing to the massive air and water pollution in the belt. The thermal power plants in the region should formulate road maps for proper utilization of fly ash and should also install fly ash brick and block manufacturing units by thermal power plants, which could be useful for building and other construction activities within a specified radius.