Biodegradation of styrene laden waste gas stream using a compost-based biofilter

Area of Science:

• Environmental biotechnology
• Bioreactor engineering
• Air pollution control

Background:

• Styrene vapor poses environmental and health risks.
• Effective biological treatment methods for volatile organic compounds (VOCs) are crucial.
• Biofiltration offers a sustainable approach to industrial air pollution control.

Purpose of the Study:

• To investigate the efficacy of a three-stage biofilter for biological treatment of styrene vapor.
• To determine optimal operating conditions for styrene removal in a biofilter.
• To characterize the kinetics of styrene biodegradation in the biofilter.

Main Methods:

• A bench-scale biofilter was constructed using yard waste compost and shredded hard plastics.
• The biofilter was inoculated with municipal activated sludge and acclimated to styrene.
• Experiments were conducted at varying styrene concentrations and empty bed retention times (EBRTs).

Main Results:

• Maximum elimination capacity (EC) of 45 gm(-3)h(-1) was achieved at a loading rate (L) of 60 gm(-3)h(-1) with an EBRT of 120 s.
• Reduced EBRTs (60 s and 30 s) led to decreased EC values of 39 and 27 gm(-3)h(-1), respectively.
• Styrene biodegradation followed first-order kinetics at low concentrations (C(In) ≤ 0.45 gm(-3)) and zero-order kinetics at higher concentrations.

Conclusions:

• The developed biofilter effectively treats styrene vapor from waste gas.
• Optimal performance was observed at specific loading rates and EBRTs.
• Understanding the kinetic behavior is essential for biofilter design and optimization.