New Delhi: Soil and water contaminated by oil could soon be returned to their natural state using bio-remediation, a process in which micro-organisms break down oil to less harmful substances.
The Central Pollution Control Board (CPCB) last week released draft guidelines for bio-remediation, minimizing the need to dispose waste at landfill sites.
CPPB has invited comments and suggestions for the guidelines to be submitted latest by 10 May.
The guidelines are in line with the Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016 notified by the Union environment ministry in April 2016.
As per the proposed guidelines, the types of hazardous oily wastes that can be bio-remediated are, “oil contamination on land or stagnant water due to accidental oil spill, residual oily sludge lying in old dumping pits, crude oily sludge generated during processing, oil contaminated drill cuttings/synthetic oil based mud waste, crude oily sludge from marketing installation/ depots/ tap off points/retail outlets of petroleum refineries and oil contaminated wastes from other allied industries".
CPCB said bio-remediation of hazardous waste shall be carried out only after obtaining authorization from state-level pollution control boards.
It also specified that in-situ bio-remediation will only be used in cases where contamination has occurred deep below the ground level or where residual oily sludge is already lying in old dumping pits and their excavation is extremely costly and difficult and in cases where stagnant water is contaminated due to oil spillage.
Another important requirement before starting in-situ bio-remediation would be that, “geological data supports that surrounding environment/population is not affected because of possible migration of pollutants till the desired level of bio-remediation is achieved".
“In rest of the cases, ex-situ bio-remediation shall be considered," the guidelines added.
In-situ bio-remediation involves treating the contaminated material without removing it from its original place at the site while ex-situ involves the removal of the contaminated material from the original place to be treated above-ground or elsewhere.
The draft guidelines said that one of the main advantages of bio-remediation is that in hydrocarbon spills remediation can be achieved at much deeper depths that cannot be reached easily without excavation and it is a less expensive than excavation.
“Bio-remediation may subsequently enable appropriate reuse of treated soil and minimizing disposal of waste to landfill thereby providing sufficient protection of human health and the environment," it added.