Slurry-Phase Bioremediation at the French Limited Superfund Site, Crosby, Texas

Site Name:

French Limited Superfund Site


Crosby, Texas

Period of

Status: Ongoing
Report covers: January 1992 through November 1993


Full-scale cleanup


Jonathan Greene
3000 Richmond Avenue
Houston, TX 77098
(713) 520-990

Gary Storms
Praxair, Inc.
39 Old Ridgebury Road
Danbury, CT 06810
(203) 837-2174

Slurry-Phase Bioremediation.
- Two treatment cells designed to hold 17 million gallons each
- Mixflo™ aeration system used to maintain dissolved oxygen concentration at 2.0 mg/L
- Tarry sludge dredged ‘and treated separately from subsoil in lagoon

Cleanup Authority:
- ROD Date: 3/24/88
- PRP Lead

SIC Code:
4953E (Waste management,
refuse systems:
sand and gravel pit disposal)
Point of Contact:
Judith Black
Remedial Project Manager
US. EPA Region 6
1445 Ross Avenue
Dallas, TX 75202
(214) 665-6739

Polynuclear Aromatic Hydrocarbons (PAHs) and Chlorinated Aliphatics;

- Primary constituents included benzene, vinyl chloride, ‘and benzo(a)pyrene
- Site contaminants included volatile organics
- (up to 400 mg/kg); pentachlorophenol (up to 750 mg/kg); semivolatiles (up to 5,000 mg/kg); metals (up to 5,000 mg); PCBs; (up to 616 mg/kg) and arsenic

Waste Source:
Disposal pit

Type/Quantity of Media Treated:
Soil and Sludge
- Approximately 300,000 tons
- Soils varied from fine grained silts to coarse sand
- Sludges - tar-like consisting of a mixture of petrochemical sludges, kiln dust, and tars (styrene and oils)

Purpose/Significance of Application:
A large full-scale application of slurry-phase bioremediation of a lagoon at a Superfund site. An innovative system was used to minimize air emissions during the remediation.

Regulatory Requirements/Cleanup Goals:
The ROD specified maximum allowable concentrations in the lagoon subsoils and sludges for 5 contaminants:
- benzo(a)pyrene (9 mg/kg), total PCBs (23 mg/kg), vinyl chloride (43 mg), arsenic (7 mg/kg), and benzene (14 mg)

The ROD specified an action level for total VOCs of 11 ppm for 5 minutes at the site boundary at any time during

- The specified cleanup criteria were met within 10 months treatment for Cell E and 11 months treatment for Cell F
- There were no exceedances of the established criteria for VOC air emissions

Cost Factors:
- Total costs were approximately $49,000,000 (including project management, pilot studies, technology development, EPA oversight, and backfill of the lagoon)
- $26,900,000 of total costs were for activities directly attributed to treatment (including solids, liquid, and vapor/gas preparation and handling, pads/foundations/spill control, mobilization/setup, startup/testing/permits, training, and operation)
- $16,500,000 were for before-treatment activities (including mobilization and preparatory work, monitoring sampling, testing, and analysis, site work. surface water, groundwater, and air pollution/gas collection and control, solids and liquids/sediments/sludges collection and containment, and drums/tanks/structures/miscellaneous demolition and removal)
- $300,000 were for after-treatment activities (including decontamination and decommissioning, commercial and non-commercial disposal, site restoration, non-treatment unit demobilization, topsoil, and revegetation)

The French Ltd. Superfund site in Crosby, Texas. is a former industrial w
Slurry-phase bioremediation of the lagoon was performed from January 1992 through November 1993. An innovative system (the MixFlo system) was used for aeration in this application that minimized air emissions while supplying oxygen to the biomass. This system used pure oxygen and a series of eductors to oxygenate the mixed liquor while minimizing air emissions. During this time, approximately 300,000 tons of contaminated sludge and soil in the lagoon were treated to levels below those specified in the ROD. In addition, air emission limits specified in the ROD were not exceeded during treatment. Total costs for the system were approximately $49,000,000, including approximately $26,000,000 for activities directly attributed to treatment. This application is notable as being the first application of slurry-phase bioremediation at a Superfund site, and included approximately $12,000,000 in technology development and pilot-scale testing work. According to FLTG, the costs for future applications of slurry-phase bioremediation depend on site-specific chemical and physical conditions with oxygen and nutrient supply being key factors affecting the cost of bioremediation systems.