BIODEGRADATION/STRIPPING OF VOLATILE ORGANICS

The potential removal mechanism for six volatile organic compounds, benzene, chlorform, methylene chloride, methyl isobutyl ketone, toluene, and trichloroethylene, was evaluated using a dimensionless ratio, γ (VOC loading rate/potential air stripping rate) estimated from VOC physical properties and conventional plant operating parameters. Theoretically, γ 1.0 implies that biodegradation must be the mechanism if significant removal is achieved. For the six compounds evaluated, γ ranged from 0.044 to 266 and the percentage air stripped ranged from 0.004% to 100% (from pilot scale laboratory data). Based on the average values, γ ≪ 1.0 indicated that air stripping was significant (chloroform and TCE: 21 to 100% stripped), γ ≈ 1 indicated a combination of biodegradation and stripping could be significant (benzene and toluene: 0.063 to 52% stripped), and, γ ≫ 1.0 implied that significant removal had to be by biodegradation (MIBK and methylene chloride: 0.004 to 0.091% stripped).