VB997^® soil Used for Soil Bioremediation
Guadalupe, California Soil Remediation Project

Guadalupe Oil field
The site, (TB9) occupies nearly 2,700 acres of the larger Guadalupe-Nipomo Dune Complex and is located on the Central California Coast in San Luis Obispo and Santa Barbara Counties. The site is bounded on the south by the Santa Maria River, on the west by the Pacific Ocean, on the north by Nature Conservancy-managed sand dunes, and to the east by agricultural land.

The principal land use at TB9 from 1946 to March 1944 was the production of oil and natural gas. The production company first acquired a 49 percent interest in the field in 1951 and purchased the remaining 51 percent in June 1953. Peak oil production of approximately 4,500 barrels per day occurred in the 1980s from 215 potential oil wells. Oil production ceased April 1994.

The Crude oil produced at TB9 was extremely viscous. To enhance the production and transportation of the heavy crude oil, a refined petroleum product referred to as diluent was introduced at the site. The composition of the diluent was similar to that of a mixture of kerosene and diesel oil, and was derived from the distillation of crude oil. Over the years, diluent was inadvertently released from the pipelines and storage tanks and is now present in soils and groundwater at the site.

Climate
The climate at TB9 is characterized as Mediterranean. The average precipitation is 12.4 inches, which is typically associated with frequent winter storm events. The average mean temperature is 56°F (based on 12 years of recorded information).

Topography
The site consists primarily of sand dunes, but the surface of TB9 is flat, with an existing 2 percent grade toward the southeast. The site is situated approximately 100 feet above mean sea level (msl) and is accessible by dirt roads.

Geology
The surface geology of the site consists of eolian dune sands of Holocene age. These sands are well sorted and predominately medium-grained sand with some fine-grained sand and a trace of silt. Thickness of the dune sand ranges from several feet in dune swales, to more than 130 feet thick at dune crests.

The dune sand is underlain by Late Quaternary alluvium, which Worts (1951) divided into two members: an upper fine-grained member “Upper Alluvium” and a lower course-grained member “Lower Alluvium.” The Upper Alluvium ranges from approximately 60 to 120 feet thick, and consists of interbeded sand and silt, with some clay. The Lower Alluvium consists of gravel and sand with sparse lenses of silt. Its thickness is similar to the Upper Alluvium.

Applicability of Biological Land Treatment
Bioremediation was chosen as the process to remediate the site. Bioremediation is the use of microorganisms to break down or degrade organic compounds through enhancements of the microbial environment. The catalysts (enzymes) produced by microorganisms degrade specific organic compounds in the soil or groundwater.

The primary reactions created during bioremediation are oxidation-reduction reactions that yield free energy that microorganisms can then use for cell growth and reproduction. Because these catalyzed oxidation-reduction reactions are dependent on the presence of microorganisms and the enzymes that they produce, environmental control is necessary for enzyme production and the desired reactions. The chemical and physical parameters of the environment must be controlled in order to stimulate the growth of indigenous (native) microbes in the soil to enhance the degradation of target contaminant compounds.

Biological degradation of petroleum hydrocarbons is a naturally occurring process. Complete destruction or mineralization of petroleum hydrocarbons ultimately results in the production of carbon dioxide, water, and microbial biomass. However, the rate of this reaction is highly dependent on a variety of factors, including the specific compound structure and its bioavailability to the microbes; the availability of oxygen, nutrients, moisture, and pH; and the nature of the soil or other matrix in which the petroleum resides. Certain compounds can be biologically degraded over a very short time (hours), whereas other compounds such as asphaltenes are slow to degrade.

The availability of oxygen has a significant effect on petroleum degradation. Studies have shown that the greatest rate of hydrocarbon degradation occurs when oxygen is used as the terminal electron acceptor (Atlas and Bartha, 1993; Schneider and Billingsley, 1990; Riser-Roberts, 1998). During biodegradation, microorganisms transfer electrons from donors to acceptors. This results in the oxidation of the electron donor and reduction of the electron acceptor. This oxidation-reduction reaction yields free energy that the microorganisms can use for cell maintenance and reproduction.

In addition to oxygen, microorganisms require relatively large amounts of nutrients such as nitrogen and phosphorous for cell growth and reproduction and the appropriate pH, moisture content, and the temperature range to enhance hydrocarbon biodegradation rates.

Solid-phase biological treatment processes are designed to remove constraints that slow degradation rates, such as limited oxygen and nutrient concentrations, to bring about rapid rates of degradation.

Application Methodology

• Day 1          Sample soil for TPH and heterotrophic plate count
                      Apply ½ lb. of VB997^® per cubic yard of contaminated product
                      Disc into soil
                      Water and maintain moisture content at 20-25%*
• Day 3          Water (moisture content to be maintained between 20-25% throughout project)
• Day 5          Water
• Day 8          Disc soil and water
• Day 10        Water
• Day 12        Water
• Day 15        Apply ½ lb. of VB997^® per cubic yard of soil
                      Disc into soil
                      Water
• Day 17        Water
• Day 19        Water
• Day 22        Disc soil and water
• Day 24        Water
• Day 26        Water
• Day 29        Soil sample for TPH and plate count
                       Disc soil
• Day 31        Water
• Day 33        Water
• Day 35        Disc soil and water
• Continue to disc soil on a weekly basis and maintain moisture content.
• Day 60        Soil sample for TPH and plate count
                      Apply ½ lb. of VB997^® to soil
                      Disc into soil
                      Water and maintain moisture content at 20-25%
• Continue to disc soil on a weekly basis and maintain moisture content
• Day 70        Soil sample for TPH

*Contractor was able to maintain only 6-8 percent moisture content throughout project.

Guadalupe, California Remediation Project Using VB997^®
Test Results

Guadalupe, California Remediation Project Using VB997^®
TPH Reduction

Overview
BioNutraTech was contacted to perform and ex-situ landfarming demonstration on 1000 cubic yards of contaminated sandy soil. The 1,000 cu. yds. contained approximately 10,000 mg/kg TPH as diluent (b.p.range approximately (nC10-nC35) from the excavation.

Sampling Locations and Methods
A 1000 cubic yard cell, eighteen inches deep was constructed with stormwater drainage channels built along the north and south sides of the construction site. Netting was installed over the stormwater collection basin to prevent birds and other wildlife from entering.

The cell was divided into quarter sections. From each quarter, five (5) approx.1 liter samples were taken from the vertical midpoint of the cell and homogenized to produce one composite batch for semi-volatile 8015 analysis and PCBs.
Include under test results