Answer: bioremediation

AnswerCrossword Clue
bioremediationThe use of either naturally occurring or deliberately introduced microorganisms or other forms of life to consume and break down environmental pollutants, in order to clean up a polluted site
bioremediationthe treatment of pollutants or waste (as in an oil spill, contaminated groundwater, or an industrial process) by the use of microorganisms (as bacteria) that break down the undesirable substances