Reviews of BV design and applications [ Thomas and Ward, 1992; Dupont, 1993; Miller, 1994; Litchfield, 1993; Hinchee, 1994] indicate BV is most applicable for removal of petroleum hydrocarbons. Contaminants degraded in laboratory and field studies have included: crude oil [ Huesemann and Moore, 1994]; toluene, ethylbenzene, and xylene mixtures [ Baker et al. , 1994]; jet fuel [ Hinchee and Arthur, 1991; Hinchee et al. , 1991; Dupont et al. , 1991]; gasoline [ Fischer et al. , 1991]; diesel fuel [ Crocetti et al. , 1993]; waste oils [ Zachary and Everett, 1993]; and aviation gasoline [ Kampbell and Wilson, 1991]. Chlorinated organic compounds have not been considered appropriate for BV due to their resistance to direct biodegradation. Wilson [1994], however, suggests these compounds can potentially be cooxidized during microbial growth on other hydrocarbons. The possibility of aerobic degradation of chlorinated compounds is discussed by: English and Loehr [1991]; Speitel and Alley [1991]; Semprini et al. [1992]; and Barbee [1994].
In contrast to SVE, BV is not constrained by contaminant volatility and is therefore applicable to contaminants with moderate to low volatility [ Hinchee, 1994]. Moreover, biodegradation rates are slower than volatilization processes for many hydrocarbons, and therefore BV is also well suited for application during periods of long term, low level removal efficiency observed in traditional SVE systems. Consequently, integrated systems have been applied which employ SVE for rapid VOC recovery during early stages, followed by low cost, long term BV operations [ Dupont et al. , 1991; Nelson et al. , 1994]. Cost analyses suggest that BV can be more cost-effective than SVE, especially when treatment of the off-gas is required [ Crocetti, et al. , 1993; Reisinger et al. , 1994]. The total cost of BV remediation for diesel fuel contaminated soils has been estimated between $10-50 per cubic yard [ Downey and Guest, 1991].