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October 16, 2009

Reclamation of crude oil contaminated soil developed

Part-2

From our Correspondent

JORHAT, Oct 16: The recent developments of crude oil contaminated soil reclamation process is a unique creation of the scientists of North East Institute of Science and Technology (NEIST). Although the technology was used by various crude oil contaminated areas in the country to make fertile the affected land but the project to set up eco-park in such sites is the only one of its kind to be projected in the State, which would be very advantageous for the affected oil drilling sites.

Talking to The Sentinel Dr Neelima Saikia, scientist of NEIST informed that, the technology that was developed to reclaim such type of degraded soil consists of two phase: (i) Bioremediation with bioformulation (ii) Followed by introduction of vegetation that is Phytoremediation. Bioformulation, which was applied to reclaim the crude oil contaminated soil for vegetation development, is a mixed culture of some types of bacterial strains isolated from soils of Assam. They have the capability of degrading hydrocarbon as well as promoting plant growth. For preparation of bioformulation, separately cultured cultures were mixed at the ratio of 1:5:3:3. The bioformulation was applied to the contaminated soil by spraying the dilute culture at a ratio of 1:1 in the first step. After three months, biochemical changes of the soil were determined and accordingly the soil was further treated with bioformulation to obtain the desired level of parameters for seed germination, root development and shoot growth.

She also said, numbers of cycles of bioformulation required for reclamation of drill site into normal cultivable soil depends on the degree of contamination. Usually bioformulation was sprayed for three times at three months interval. Since the bioformulation is site specific, changes are made in the formulation according to the nature of contaminated soil.

Once the area is reclaimed, fast growing non-edible plants are introduced to decontaminate polluted soil further. As the drill sites areas are contaminated with numerous elements and plant absorbs all dissolved elements and ions whether it is toxic or not, therefore, fast growing, non-edible economically important and drill sites feasible plants like Tectona grandis, Gamelina arborea, Michelia champaca, Anthocephalus indicus, etc., were selected for this study. Plant species were selected through a series of seeds and seedling screening test performed in the laboratory. To obtain the comparative data normal cultivated soil and virgin soils were considered for this study as control.

The process of reclamation of crude oil contaminated soil can be used by oil industry like ONGC, Oil India in the effected areas for revival of the soil. It is observed that contaminated soils have direct effect on socio-economic life of thousands of inhabitants in and around oil industries/installation. If soil can be reclaimed to grow vegetation/crops, etc., it will improve the economic life of the people surrounding such industries.

Noteworthy that, the team have already reclaimed some of such degraded sites with considerable god results. Presently, they are engaged in the bioremediation of three abandoned drill sites, two of which are located in Geleky and one in Amguri. Here they have planted some good numbers of economically important timber yielding plants with an objective of developing all the sites into eco-parks. (Concluded) THE SENTINEL

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