Resource detail

Title: Converting power plant waste (fly-ash) into valuable products (cement)
Organization:Dirk India Pvt. Ltd.
Source:Narang R K (Ed). 2006. Case studies of Corporate Environmental Excellence. In series “Cleaner in Cheaper, Vol. 4”. New Delhi, India: The Energy and Resources Institute, 174pp.

Background: The demand for energy has been increasing in India and a large portion (approx. 70%) of the demand is met by harnessing thermal energy of coal. These thermal power stations use approximately 300MT (million tons) of coal per annum. Coal has very high ash content (over 45%) and hence combustion of coal generates a significant quantity of ash as residue. Although India already generates an excess of 100MT of fly ash per annum, the quantity is expected to double and rise even further owing to the growing demand for power in the country.

Challenge: Fly ash is a major air pollutant which remains persistent in the atmosphere as SPM (suspended particulate matter) causing respiratory problems and health hazards. It is usually disposed off by dumping onto open lands causing land pollution, decreased fertility and making the land unfit for agriculture and cultivation. A staggering amount of 10 billion rupees is spent annually in the exercise to dump approximately 85% of the fly ash produced, over 2,00,000 acres of land that is reserved for this purpose. When discharged in wet form, fly ash silt up the natural drainage system and contaminates surface and sub-surface water, adversely affecting the photosynthesis process and disrupts the food chain. With the increasing demand for energy and dependence upon thermal power plants for generation of power, the quantity of fly ash generated in the process can only be expected to rise. The present system is expensive and uses up valuable land resource that could have been put to better use. Hence there is a need for safe disposal of the waste and a concise plan for fly ash management.

Initiative: Scientific research revealed that waste fly ash was actually a valuable raw material and could be used as replacement of cement in mortar and concrete. It could also be utilized in other areas including dyke raising, brick manufacturing, roads and embankment construction, stowing material for mines and so on.

DIPL, at its Nashik Pozzocrete Plant, converts Indian fly ash from waste products into valuable inputs for the construction industry. The plant houses labs to facilitate the testing of physical and chemical parameters of fly ash and the company also signed a 30 year contract with MSEB (Maharashtra State Electricity Board) for lifting the fly ash waste material from its Nashik thermal power station, in October 2000.

Dirk collects floating fly ash from 25 ash disposal lagoons across the country and produces thousands of tons of Pozzocrete recycled from the waste and markets it in India and abroad as a cement replacement quality enhancing product. It is used in the mix design for various cement applications and has the product has managed to establish a market for itself. It has been awarded the ISI mark by the BIS and has been acknowledged as a cement replacement product under IS: 3812. The company boasts of a long list of highly successful buyers who trust the high quality of its product.

Outcome/Benefits: • Dirk Pozzocrete can theoretically replace 30% of the current cement consumption and costs half as much as cement. Thus it offers a cost effective alternative allowing for savings worth billions of rupees for the state of Maharashtra. Smaller quantities of raw materials for cement production are excavated and hence there is conservation of natural resources. Even the energy meant for production of cement is now saved. • By this process a waste product previously causing nuisance has been successfully transformed into a valuable raw material. Fly ash therefore is no longer a persistent environmental hazard as it is consumed in the cement making process. Therefore we see a successful waste management operation. • The atmospheric pollution caused due to pollutants like CO2, NOx and CH4 is reduced as cement consumption is reduced by 35% by using fly ash. Also, the land which was previously used as dumping ground can now be put to better use.

Commercially tested: Yes