AMADOR COUNTY AIR POLLUTION CONTROL DISTRICT

RULE 903 - CONTAMINATED SOIL REMEDIATION
(Last Revised 06/28/94)

The purpose of this Rule is to limit the emission of organic compounds from soil that has been contaminated by organic chemical leaks or petroleum chemical leaks or spills, to describe an acceptable soil remediation procedure, and to reduce public exposure to emissions for toxic compounds.

903.1. Definitions.

Active Storage Pile. A pile of contaminated soil to which soil is currently being added or from which soil is currently being removed. Activity must have occurred or be anticipated to occur within one hour to be current.

A. Aeration. Unheated exposure of contaminated soil to the open air.

B. Aeration Depth. The smaller of the following: the actual average depth of contaminated soil or 0.5 feet multiplied by the daily frequency with which soil is turned.

C. Aeration Volume. The volume of soil being aerated shall be calculated as follows: the exposed surface area (in square feet) shall be multiplied by the aeration depth. The exposed surface area includes the pile of excavated soil unless the pile is covered per Rule 903.2.E.

D. Bioremediation. The cleaning up of contaminated soil by an approved biological process.

E. Contaminated Soil. Soil which has an organic content, as measured in Rule 903.3.B, exceeding 50 ppm by weight. The soil shall not contain more than 1 ppm benzene by weight. The soil to be treated shall be certified as nonhazardous by the generator or their qualified consultant, with concurrence of the appropriate administering agency, such as Environmental Health or Cal-EPA's Department of Toxic Substances Control.

F. Organic Compound. Any compound of carbon, excluding methane, carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonate and ammonium carbonate.

G. Organic Content. The concentration of organic compounds measured in the composite sample collected and analyzed using the procedures in Rule 903.3.B.

H. Remediation. The cleaning up of contaminated soil by an approved process.

I. Sensitive Area. Any area where there are substantial concentrations of people for an extended period of time. These areas include, but are not limited to a park, a shopping center, a government center, or a residential neighborhood.

K. Soil Washing. A process which uses specially formulated detergents and water in washing equipment to remediate gasoline, diesel, or oil contaminated soil.

L. Thermal Remediation. A process in which contaminated soil is fed into a rotary drum where a hot air stream drives off the moisture and organic compounds. The gas stream is then channeled to the control device system and discharged to the atmosphere.

903.2 Requirements.

A. Excavation.

1. Soil will be kept moist to contain hydrocarbons and reduce dust emissions during excavation.

2. Soil will be placed on an impermeable material, and covered securely with an impermeable material until proposed treatment method has been submitted and approved by the District in the form of a Permit to Operate or a written exemption from the Permit to Operate requirement.

B. Aeration Without Control Device. Based on the specific level of contamination, a person shall not aerate contaminated soil at a rate in excess of that specified in the following table. The limitations in the table apply to the entire facility, and indicate the volume of contaminated soil that may be added, on any one day, to soil that is already aerating.

C. Aeration with a Control Device. Soil may be aerated at rates exceeding the limitation of 903.2.B. above, provided emissions of organic compounds to the atmosphere are reduced by at least 90% by weight.

D. Bioremediation soil washing, thermal incineration, or other remediation proposals will be evaluated from the Authority to Construct application and appropriate conditions placed on the Permit to Operate. The conditions shall ensure safe operation, limit emissions, and prevent creation of a public nuisance. These processes are also subject to the risk assessment requirements of 903.3.C and total hydrocarbon release to the atmosphere per table in 903.2.B.

E. Storage Piles. Contaminated soil which is not being aerated shall be covered except when soil is being added or removed. Any uncovered contaminated soil will be considered to be aerated. The soil may be covered with an impermeable covering, provided no head space where vapors may accumulate is formed and provided the covering is in good condition and is secured adequately so as to minimize emissions to the atmosphere.

F. Exemptions.

1. The requirements of this rule shall not apply to the emergency soil decontamination which may be performed by, under the jurisdiction of, or pursuant to the requirements of, an authorized health officer, agricultural commissioner, fire protection officer, or other authorized agency officer. Whenever possible, the APCO shall be notified prior to commencement of such action.

2. Contaminated soil exposed for the sole purpose of sampling shall not be considered to be aerated. Removal of soil for sampling shall not qualify a pile as "active."

3. Upon receipt of an Authority to Construct application demonstrating that the soil is contaminated exclusively by hydrocarbons with a boiling point of greater than or equal to 302 degrees F (diesel oils, hydraulic oils, etc.), the aeration limits in 903.2.B shall be waived. Written permission to aerate the soil under the exemption and waiver from the Permit to Operate requirement will be issued.

903.3 Administrative Requirements.

A. Notification. The person responsible for the aeration of any contaminated soil shall provide the following information to the District in the form of an Authority to Construct/Permit to Operate application:

1. Estimated total quantity of soil to be aerated.

2. Estimated total quantity of soil to be aerated per day.

3. Estimated average degree of contamination, or total organic content of soil.

4. Chemical composition of contaminating organic compounds and a description of the basis on which these estimates were derived (soil analysis test reports, etc.).

5. Indication of whether the site is within 1000 feet of a school, hospital, health care facility, or other sensitive area.

B. Testing Requirements.

1. Sampling.

a. Each 50 cubic yard pile shall be considered to have four equal sectors. One sample shall be taken from the center of each sector. Samples shall be taken at least three inches below the surface of the pile. Samples shall be composited from the four sectors by the test laboratory.

b. One composite sample shall be collected and analyzed for every 50 cubic yards of excavated contaminated soil to be remediated. At least one composite sample shall be collected from each inactive, uncovered storage pile within 24 hours of excavation. Samples are not required if soil is uncontaminated.

c. Samples shall be taken using one of the following methods:

(1) Samples shall be taken using a driven-tube type sampler, capped and sealed with inert materials, and extruded in the laboratory in order to reduce the loss of volatile materials; or

(2) Samples shall be taken using a clean brass tube (at least three inches long) driven into the soil with a suitable instrument. The ends of the brass tube shall then be covered with aluminum foil, then plastic end caps, and finally be wrapped with a suitable tape. The samples shall then be immediately placed on ice or dry ice for transport to a laboratory.

2. Measurement of organic content. Organic content of soil shall be determined by the methods found in Appendix A of the "Leaking Underground Fuel Tank Field Manual" of the State Water Resources Control Board, or the "Tri-Regional Board Staff Recommendations for Preliminary Evaluation and Investigation of Underground Tank Sites," or any other method approved by the APCO, in writing, in advance. Benzene content in soil is to be quantified as well as the total organic content.

3. Total hydrocarbon and benzene emission rates will be estimated using the following factors:

a. The average total hydrocarbon or benzene concentration found by sampling and analysis of the soil stockpile.

b. Five days of aeration.

c. The total volume of soil in cubic yards.

d. A soil density of 3900 lb/cubic yard.

C. Risk Assessment. At the discretion of the APCO, no remediation project may occur until a screening level risk assessment is completed and submitted, using as a minimum, the screening risk assessment using the CAPCOA "Air Toxics Assessment Manual," to the APCO for review and approval.

D. Final Disposition. Written notification of the final disposition of the soil, including final laboratory test results, shall be submitted to the District within one week of the completion of the remediation. The notification shall include test results showing the final hydrocarbon levels.

903.4 Additional Requirements. Upon excavation of underground tanks or exposure of 50% of the underground piping at retail service stations, the retail service station is required by state law to have Phase I and Phase II vapor recovery installed before commencing to sell gasoline again (see District Rule 902 for requirements). An Authority to Construct application separate from the remediation application must be filed for the installation of the vapor recovery systems.

Additional permits or approvals may be required from other agencies.