“One must be a sea, to receive a polluted stream without becoming impure.”? Friedrich Nietzsche, Thus Spoke Zarathustra Fly Ash is a grossly under-utilized resource for a long time. Fly ash contitutes of many heavy metals like zinc, lead,radium,nickel, vanadium, arsenic, selenium, uranium, thorium, molybdenum, etc.
that are known to be detrimental to health in sufficient quantities. Though these elements are found in very low concentrations in fly ash, their presence has flustered the users . An estimate of about a billion tonnes of fly ash is dumped into poorly designed and maintained ash ponds, polluting air, water and land. Although fly ash has an immense potential in agriculture, there are some possible concerns which need attention , such as release of toxic elements into ground water, reduced germination of crops at high levels of fly ash applications, uptake of heavy metals and toxic elements by the plants etc.
Fly Ash Utilisation Programme has commissioned a set of technology demonstration projects under different agro-climatic conditions and soil-crop combinations towards a confidence building exercise. Fly ash is useful in modification of soil texture and bulk density, improvement of water holding capacity, optimisation of soil pH, as a micronutrient supplement to soil and creation of conducive condition for better plant growth. Since the introduction of FaL-G in 1991, fly ash brick activity has been revolutionized in India. Founder, Dr Bhanumathidas and Kalidas have simplified the process by adding gypsum and lime, converting the calcium aluminates into calcium alumino-sulphates resulting in high early strengths.FaL-G brick does not need any pressure and gets cured at ambient temperature of 20-40 °C.
By avoiding both press and heating chamber, the multi-million plant costs to a few lakhs, within the reach of micro units. India is still developing and needs to reach enormous demand for building material. This permits two things—first, to reuse the fly ash at power plants which otherwise disturbs the ecological balance and second, it will also minimise use of clay bricks whose production is highly polluting and damages the topsoil. Therefore, such a move could help, but key would be to ensure implementation of such a decision. In the wake of the Bhopal Gas Tragedy, the Government of India enacted the Environment Protection Act of 1986 . Section 3 of the said Act empowers the Central Government to take measures to protect and improve environment.
In 1994, the government of India started the fly ash mission (FAM), under the Technology Information Forecasting and Assessment Council of the Department of Science and Technology (DoST), with the aim to increase fly ash utilisation in the country. 55 in 1st phase and 13 technology demonstration projects in second phase had been undertaken for the utilization of this salvageable fritter. On 14th September 1999, a principal notification was published in the gazette of India that instructed brick, tiles or block manufacturers within a radius of fifty kilometers from coal or lignite based thermal power plants, to use fly ash in construction activities without mixing at least 25 per cent with soil on weight to weight basis. Manufacture of ash-based products in construction activity such as in road laying, embankments , landfill to reclaim low lying areas including back filling in abandoned mines or pitheads and any other use shall be carried out in accordance with specifications and guidelines laid down by the State Public Works Departments and other Central and State Government agencies. To tackle the issue, the govt.
issued a 5- year plan for 100% utilization of ash. The revised order in 2003, expanded to a radius of 100 kilometres of a coal based thermal power plant. It permitted only pond ash to be used for compaction in accordance with the by-laws, regulations and specifications laid down. Other laws included – soil required for top or side covers of embankments of roads and flyovers shall be excavated from the embankment site, the topsoil should be kept or stored separately, voids created due to soil borrow area shall be filled up with ash with proper compaction and covered with topsoil kept separately as above.
This would be done as an integral part of embankment project within the time schedule of the project. The construction agencies are yet to achieve their targets of utilization of fly ash based products even after 31st August, 2007, the date prescribed for 100% utilisation of fly ash based products in the said notification of 1999. Over the years , the the policies were intensified to make use of more fly ash. Pond ash to be supplied free of cost for purpose of landfilling.
Fly ash bricks, blocks, tiles, etc. made with fly ash, lime, gypsum, sand, stone dust, cement , etc. had to use fly ash as 50% of raw material and further 5 year plans for 100% utilization were also suggested in 2009. The use of flyash products was made compulsory for any construction agency. Later in 2016, the ministry made it mandatory for power plants to give fly ash free of cost to users within 300-kilometre-radius.The notification also made it mandatory for cement industries, within same radius, to use fly ash for manufacture of the cement as per the specifications of Bureau of Indian Standards (BIS). The cost of transportation is to be borne collectively by the thermal power plant and the industry concerned.
Low lying lands reclaimed with fly ash are being used for growing vegetable crops at Rihandnagar, U.P. To encourage manufacturers using fly-ash in manufacturing of their products, the Government of Uttar Pradesh had issued notification dated 18.06.
1997, granting “rebate of tax” to the dealers in the State of Uttar Pradesh using fly-ash purchased within the state.Some difficulty in achieving the goal lies in getting manufacturers to use fly ash. Many, refuse to deviate from traditional brick making as they do not have to pay any royalty on amounts of soil dug out. Government notification stresses upon all clay brick manufacturers to mix at least 50 per cent ash in clay for brick making. Fly ash considered as a polluting industrial waste in 1994 has become a sought after material today. Earlier, there were neither fly ash users nor willing workers but now, utilization has reached to about 65 million tonnes per year from the level of 1 million tonnes per year.
Statutory and policy measures supported by national standards, specifications and guidelines are now in place to facilitate large-scale utilization on sustainable basis thus attracting thousands of people to work in this area. A lot of research has turned around the image of fly ash from ” a polluting industrial waste ” to “a resource material ” but a lot more needs to be done on these fronts to take the utilization levels to 100%.