management of fly ash in agriculture

Energy requirements for the developing countries in particular are met from coal-based thermal power plants. This presentation attempts to highlight the management of fly ash, in order to save our environment.

Asia’s largest integrated bauxite- alumina complex is established by NALCO at Damanjodi. It solely depends upon the thermal co-generation plant to run the industry. In this thermal plant coal is used to produce steam to run the refinery. It produces (18.5 x 4) MW of energy per day with about 30MT fly ash. Fly ash accumulation is a major storage problem is such type of plants.

 WHAT IS FLY ASH?

Fly ash is the residue of combustion of Pulverized coal and Lignite produced in thermal power plants.

NEED OF THE STUDY

We have selected this project because accumulation of fly ash is a great problem at NALCO on the other hand annual production of crops is low in Koraput District because the tribals are not able to use fertilizers, because of poverty. To solve the above problems we have selected this project.

METHODOLOGY

We had conducted a survey among some local farmers of Gaudaguda and Khalpadi village on 28^th and 30^th September 2012 and collected information from them about the impact of fly ash on their health and surroundings. There were some interviews conducted with certain officials of NALCO such as the General Manager, the Deputy General Manager, the Asst. General Manager of different departments related with fly ash and environmentalists of in the locality and agriculturists of Semliguda block in month of October. Data were collected from them.  A report of an Experimental Project conducted by NALCO was also collected. Certain field studies were made at the ash pond of NALCO, the dry fly ash collection site, and the nurseries of NALCO.  

WHY FLY ASH IS A GREAT ENVIRONMENTAL PROBLEM?

Coal based power generation is the principal source of energy in India and many other countries. My point is that Indian coal has high ash content (40%-50%) and low calorific value (3500 kcal/kg – 4000 kcal/kg) as a result of which huge quantity of fly ash is generated. This fly ash would require a large area of land for the construction of ash ponds.

WHAT ARE THE IMPACTS OF FLY ASH IN NEARBY LOCALITY OF NALCO?

The power requirement of the refinery plant of NALCO generates a huge amount of fly ash which is ultimately dumped into a separate ash pond. During our visit, the complains received from villages surrounding fly ash pond indicated that whenever it rains the pond sometimes overflows and their toxic material is spilled into the nearer stream and river causing water pollution. On the basis of their interviews, we found many cases of:

·         Gastric disorders,

·         asthma,

·         diarrhoea,

·          Eye rashes,

·         dermatitis in human and cattle

·         Continuos exposure can lead to ulceration of the eye and cataract.

Fly ash consists of minute gas like particle and its deposition on the leaves inhibits the normal transpiration and photosynthesis activities of plants. But we didn’t found any such cases during our survey because of the use of Electrostatic Precipitators in the thermal power plant. When the fly ash is spilled in the crop fields it has no harmful impact on agriculture.

FINDINGS

In our findings we found that NALCO has adopted several measures for disposal of fly ash. These include:

i.              DISPOSAL IN ASH POND

ii.            LOW LAND FILLING

iii.           MINE VOID FILLING

iv.           FOR USE IN CEMENT FACTORY

v.            MAKING FLY ASH BRICKS

We even found a report of experimental project conducted by NALCO to demonstrate the use of fly ash in agriculture. According to this report it was conducted for 5 years starting from 2006 to 2010.

The aim of this was to dispose off fly ash yet increase the harvest in agricultural fields in the surrounding areas. The soil was prepared by mixing 10%, 20%, 30%, 40% and 50% fly ash in respective field divisions. According to five years report (2006-2010) the optimum yield obtained when the concentration of fly ash in soil was 20%. The graph starts declining as the concentration of fly ash is increased subsequently. RRL, Bhopal and Bhubaneswar experimented and reported that there is no case of heavy metals and radioactive elements found in food grains harvested in fly ash amended soil.

Hence we recommend the use of fly ash in agriculture as:

i.              It improves permeability status of soil.

ii.             Improves fertility status of soil

iii.            Improves soil texture.

iv.           Improves water holding capacity / porosity.

v.            Optimizes pH value.

vi.           Improves soil aeration.

vii.          Reduces crust formation.

viii.         Provides micro nutrients like Fe, Zn, Cu, Mo, B, Mn, etc.

ix.           Provides macro nutrients like K, P, Ca, Mg, S etc.

x.            Improves the nutritional quality of food crop.

xi.            It acts as soil ant-acid (Agricultural lime application contributes to global warming as Intergovernmental Panel on Climate Change (IPCC) assumes that all the carbon in agricultural lime is finally released as CO₂ to the atmosphere. It is expected that use of fly-ash instead of lime in agriculture can reduce net CO₂ emission and also reduce global warming.)

Therefore I want to say that use of fly ash in agriculture is the best way to dispose off fly ash in eco friendly manner.

(SUGGESTIONS & IMPLICATIONS) IN OUR FURTHER RESEARCH WE FOUND THAT:

i.              According to the study made by Anamalai University, Tamil Nadu a new type of application of fly ash in agriculture sector is emerging, which is the use of fly ash as pesticides and insecticide. This is because of the presence of some of the element in fly ash effective to kill crop-damaging insects especially present in the soil. Research and Development (R&D) efforts have also been directed towards this.

ii.            According to the study made by Thapar University, Patiala now plants can even be grown in 100% fly ash conditions by the application of Arbuscular Mycorrhizal fungi. Application of Arbuscular Mycorrhizal (AM) fungi in for growth of Bamboo plants in pond fly ash has given the new dimension of utilization of fly ash in afforestation. Hence use of AM fungi in areas surrounding the ash pond is recommended.

iii.           According to the study made by National Botanical Research Institute, Lucknow plants like Haldina Cordifolia, Mangifera Indica can play important role in reducing air pollution by accumulating the dust particles and metals, hence the concept of green belt development in and around fly ash handling areas is recommended. 

iv.           Research made by Annamalai University, Tamil Nadu states that fly ash could be converted into a valuable vermi-compost by growth of indigenous earthworm Lampito mauritii. This study explored the potential role to convert the flyash into best manure and reduce the cost of disposal of fly ash.

CONCLUSION

Finally we recommend that use of fly ash in Agriculture and biomass production should not just be confined to the Experimental plots, report papers and nurseries but should be spread among the areas surrounding the Thermal Power Plant and within the Thermal power plant. This will not only solve the problem of scarcity of fertilizers but also help in efficient management of fly ash. Use of fly ash in agriculture will definitely reduce the use of chemical fertilizer and solve the problem of tribal pockets of Odisha. Hence it is a matter for another green revolution.

Let us harness Billion Dollars of resources that has been wasted away so far.