A mesocosm study was evaluated to elucidate
the influence of amendments such as microbial consortium,
plant (
Vetiveria zizanioides
), bulking agent (wheat husk)
and nutrients on remediation of oil sludge over a period of
90 days. The experiment was conducted in a 15 m
2 plot
which was divided into eight units comprising of soil
sludge mixture (1:1) at CSIR-NEERI premises. During the
experiment, oil degradation was estimated gravimetrically
and polyaromatic hydrocarbons (PAHs) were quantified on
GC–MS. Additionally, dehydrogenase activity was also
monitored. The treatment integrated with bulking agent,
nutrients, consortium and plant resulted in 28-fold
increased dehydrogenase activity and complete mineralization
of higher PAHs. Furthermore, 72.8 % total petroleum
hydrocarbons (TPH) degradation was observed in
bulked treatment with plant, nutrients and consortium followed
by 69.6 and 65.4 % in bioaugmented treatments
with and without nutrients, respectively, as compared to
control (33.4 %). A lysimeter study was also conducted
simultaneously using Vetiver and consortium to monitor
groundwater contamination by heavy metals in oil sludge
which showed a marked decrease in the concentrations of
metals such as lead and cadmium in leachates. This study
validates a holistic approach for remediation of
oil sludge contaminated soils/sites which is a burning issue
since decades by the use of microbe assisted phytoremediation
technology which not only solves the problem of oil
contamination but also takes care of heavy metal
contamination.
