Characterizing biodegradation parameters for toluene contaminated groundwater
Student name: Mr Mohit Bhatia
Guide: Dr Arun Kansal
Year of completion: 2012
Host Organisation: Simulation Laboratory, Civil Engineering Department, IIT Delhi
Supervisor (Host Organisation): Dr Brijesh Kumar Yadav
Abstract: LNAPLs (Light non-aqueous phase liquids) are common contaminants in the environment.
These are produced as a result of oil refining process. These have less or no solubility in water
and form a layer on groundwater. These have harmful effects on human health and need to be
removed. However they get degraded with time by microorganisms but the rate is slow and also
depends on different environmental factors like salinity, temperature, moisture content. The
objective of this study was first to investigate the impact of salinity which is one of the
environmental factors on the rate of bioremediation of LNAPL and then study the degradation
kinetics of Toluene in groundwater. For this batch experiments were done in lab. The batches
contained groundwater which was collected from the polluted site near an oil refinery in
Panipat. For salinity experiment saline solutions of different concentrations were prepared and
equal volume of toluene was injected. Control was also prepared for these batches by injecting
HgCl2 to prevent degradation. Biodegradation rate decreased with increasing salinity. Then
batch experiment was done to find the degradation parameters of toluene through Monod’s
Kinetics. µmax (maximum utilization of substrate) and Ks (Half saturation coefficient) were
calculated. Value of µmax was approximately 10 and thus Ks was 5 which is half of the µmax.
These values were used to calculate specific growth rates (µ) at different toluene
concentrations.
Keywords: NAPLs, Bioremediation, BTEX, LNAPLs, Toluene, Monod’s Kinetics
