Bioremediation of oily sludge by solid complex bacterial agent with a combined two-step process

Area of Science:

• Environmental Microbiology
• Bioremediation Technologies
• Waste Management

Background:

• Oily sludge poses significant environmental challenges due to high concentrations of total petroleum hydrocarbons (TPH).
• Conventional treatment methods for oily sludge can be inefficient and costly.
• Bioremediation offers a sustainable alternative for treating petroleum-contaminated waste.

Purpose of the Study:

• To develop and evaluate a novel two-step bioremediation process for oily sludge using solid complex bacterial agents (SCBA).
• To assess the efficiency of SCBA in degrading TPH and reducing COD in oily sludge.
• To demonstrate the scalability and industrial applicability of the developed bioremediation technology.

Main Methods:

• Development of SCBA by immobilizing highly efficient bacterial strains with bran.
• Implementation of a two-step process: biosurfactant-assisted oil recovery followed by SCBA biodegradation.
• Optimization of biodegradation conditions, including an optimal temperature of approximately 35°C.
• Large-scale field testing involving 5 tons of oily sludge.

Main Results:

• Four isolated bacterial strains demonstrated high efficiency in degrading TPH (96.6%) and reducing COD (92.6%).
• SCBA formulation showed improved performance compared to individual strains, with optimal activity at 35°C.
• The two-step process effectively treated oily sludge with high TPH content (>10 wt%) within 60 days.
• Field tests achieved 93.8% TPH removal and 91.5% COD reduction, confirming technology feasibility.

Conclusions:

• SCBA offers advantages for storage and transportation over liquid media.
• The developed two-step bioremediation process is effective for treating high-TPH oily sludge.
• The technology is feasible and superior for industrial applications, as confirmed by large-scale field tests.