EVALUATION REPORT FOR A PERMIT TO CONSTRUCT
Soil Extraction

APPLICANT'S NAME:

MAILING ADDRESS:

EQUIPMENT ADDRESS:

EQUIPMENT DESCRIPTION:

    UNDERGROUND AIR SPARGING VAPOR EXTRACTION AND TREATMENT SYSTEM, CONSISTING OF:

1) EXTRACTION WELLS AND DUCTS.

2) AIR SPARGING VAPOR EXTRACTION SYSTEM, MAKE____________, MODEL NO. ______, SERIAL NO. _________, WITH A GAS/LIQUID SEPARATOR, ____-GALLON CAPACITY.

3) THREE CARBON ADSORBERS IN SERIES, MAKE____________, MODEL NO. _______, EACH WITH ____ POUNDS CAPACITY OF GRANULAR ACTIVATED CARBON.

4) EXHAUST SYSTEM CONSISTING OF A _._ HP BLOWER VENTING THROUGH A STACK, ___’- ___" DIA. X ___’- ___" H., _____ SCFM.

HISTORY/PROCESS DESCRIPTION:

A/N ______ was validated on __/__/2000 as Class 1 to construct an underground soil vapor extraction and treatment system, to be located at the corner of ______ Street and _______ Avenue in _______. There is a school, ______ ______ School, located at ________ _______ Avenue, _______, CA _____, that is within 1000 feet from the proposed equipment, and which triggers the Rule 212 public notice requirement.

The applicant initially proposed two carbon adsorbers in series, however, has agreed to add an additional carbon adsorber (three in series total) in acknowledging the sensitivity of a nearby school. Soil samples indicate non-detectable concentrations of petroleum hydrocarbons, however groundwater samples collected at adjacent monitoring wells indicate petroleum hydrocarbon contamination. Therefore this system proposes to inject air to sparge off the VOC contaminants away from nearby residences, to be collected by the underground vapor extraction wells and treated in the carbon adsorbers. The source of the petroleum hydrocarbon contamination is thought to be from a fueling and dispensing facility at the adjacent fire station.

CALCULATIONS

This control system is estimated to be 99.75% efficient in controlling hydrocarbon emissions.

The applicant estimates that 900 mg/m3 (247 ppmv as hexane MW 86.18) of VOC can be collected in the extraction system.

VOC (R1) = 0.900 g/m3 x 200 cfm x m3/35.3145 cf x 60 min/hr x lb/453.593 lb

                 = 0.674 lb/hr x 24 hr/day

                 = 16.18 lb/day x 365 day/yr

                 = 5906 lb/yr (2.95 ton/yr)

VOC (R2) = 0.674 lb/hr x (1-99.75/100)

                 = 0.00169 lb/hr x 24 hr/day

                 = 0.040 lb/day x 365 day/yr

                 = 14.8 lb/yr

Estimate breakthrough emissions at first stage to be 10% (90% control) of uncontrolled emissions.

Breakthrough = 0.0674 lb/hr x mole/86.18 lb x 379 ft3/mol x hr/60 min x min/200 ft3 x 106

                      = 25 ppmv as hexane

Estimated Benzene first stage outlet concentration = 36.3 ppmv x (1-95/100)
                                                                           = 2 ppmv

Toxics:

The applicant indicates that the inlet contaminants are petroleum hydrocarbons and include benzene 120 mg/m3 (36.3 ppmv), ethylbenzene 130 mg/m3 (29 ppmv), toluene 300 mg/m3 (77 ppmv) and xylenes 250 mg/m3 (55.7 ppmv). Risks are tabulated in the attached risk assessment spreadsheet assuming an overall control efficiency of 99.75%. The results are summarized below:

Benzene = 0.120 mg/m3 x lb/453.593 x lbmol/78.11 lb x 379 ft3/lbmol x m3/35.3145 ft3 x 106

              = 36.3 ppmv

Ethylbenzene = 0.130 mg/m3 x lb/453.593 x lbmol/106.17 lb x 379 ft3/lbmol x m3/35.3145 ft3 x 106

                     = 29 ppmv

Toluene = 0.130 mg/m3 x lb/453.593 x lbmol/92.14 lb x 379 ft3/lbmol x m3/35.3145 ft3 x 106

             = 77 ppmv

Xylenes = 0.130 mg/m3 x lb/453.593 x lbmol/106.16 lb x 379 ft3/lbmol x m3/35.3145 ft3 x 106

             = 55.7 ppmv

TOXIC RISK SUMMARY:

  • Maximum Individual Cancer Risk (MICR):

    • Residential/Sensitive Receptor:      6.66 E-07:

    • Commercial Receptor:      1.59 E-08

  • Acute Hazard Index (HIA):

    • Cardiovascular or blood system:      1.85 E-04

    • Central or peripheral nervous system:  2.43 E-05

    • Immune system:      1.85 E-04

    • Reproductive system:      2.09 E-04

    • Respiratory system:      5.83E-05

    • Eye:     5.83 E-05

RULES EVALUATION:

Rule 212:

Compliance with the provisions of Division 26 of the State Health and Safety Code is expected. A public notice was distributed as required per Rule 212 (c)(1) since the equipment is to be located within 1000 feet from the outer boundary of a school.

Rule 401:

Compliance is expected.

Rule 402:

Compliance is expected.

Rule 404:

Compliance is expected

Rule 1166:

Compliance with 1166(c)(3) is expected.

REGULATION XIII - New Source Review

The requirements of 1303(a) BACT are satisfied with carbon adsorption for volatile organic compound control. Modeling per Rule 1303(b)(1) is not applicable to VOC’s. Rule 1303(b)(2) emission offsetting is exempted under rule 1304 since thresholds are not exceeded.

Rule 1401:

Cancer risk is expected to be less than one in a million for residential and commercial receptors. Acute hazard indices are expected to be below 1.0; chronic hazard indices are not calculated since chronic hazard compounds are not expected.

DISCUSSION

It has been determined that the equipment will operate in compliance with all the applicable Rules and Regulations of the AQMD.

RECOMMENDATION

Once Rule 212’s public notice distribution has been satisfied, issue a permit to construct subject to conditions:

PERMIT CONDITIONS

  1. OPERATION OF THIS EQUIPMENT SHALL BE IN COMPLIANCE WITH ALL DATA AND SPECIFICATIONS SUBMITTED WITH THE APPLICATION UNDER WHICH THIS PERMIT WAS ISSUED, UNLESS OTHERWISE NOTED BELOW.

  2. THIS EQUIPMENT SHALL BE PROPERLY MAINTAINED AND KEPT IN GOOD OPERATING CONDITION AT ALL TIMES.

  3. UPON COMPLETION OF THIS OPERATION, ANY REMAINING VAPOR EXTRACTION WELLS AND DUCTS SHALL BE CAPPPED TO PREVENT VAPORS FROM VENTING TO THE ATMOSPHERE. VAPORS SHALL NOT BE EXTRACTED FROM THE SOIL UNLESS THEY ARE VENTED TO THE VAPOR CONTROL SYSTEM, WITH NO DETECTABLE LEAK BETWEEN THE OUTLET OF THE BLOWER AND THE OUTLET OF THE VAPOR CONTROL SYSTEM.

  4. AN IDENTIFICATION TAG OR NAMEPLATE SHALL BE DISPLAYED ON THE EQUIPMENT TO SHOW THE MANUFACTURER, MODEL NUMBER AND SERIAL NUMBER. THE TAG(S) OR PLATE(S) SHALL BE ISSUED BY THE MANUFACTURER AND SHALL BE ADHERED TO THE EQUIPMENT IN A PERMANENT AND CONSPICUOUS POSITION.

  5. THE MOST CURRENT CONTACT PERSON’S NAME, COMPANY AND PHONE NUMBER SHALL BE DISPLAYED IN A PERMANENT AND CONSPICUOUS LOCATION.

  6. A FLOW INDICATOR SHALL BE INSTALLED AND MAINTAINED AT ALL INLET STREAMS TO THE VAPOR CONTROL SYSTEM TO INDICATE THE TOTAL AIR FLOW RATE IN CUBIC FEET PER MINUTE (CFM). IN CASE A PRESSURE SENSOR DEVICE IS USED IN PLACE OF THE FLOW INDICATOR, A CONVERSION CHART SHALL BE MADE AVAILABLE TO INDICATE THE CORRESPONDING FLOW RATE, IN CFM, TO THE PRESSURE READING.

  7. THE TOTAL INLET FLOW RATE SHALL NOT EXCEED 200 SCFM.

  8. THE VOLATILE ORGANIC COMPOUND (VOC) CONCENTRATION SHALL BE MEASURED EACH DAY DURING THE FIRST TWO WEEKS OF OPERATION AND ON A MINIMUM WEEKLY BASIS THEREFAFTER AT THE INLET AND OUTLET OF THE FIRST STAGE CARBON ADSORBER. THE VOC CONCENTRATION SHALL BE MEASURED USING A FLAME IONIZATION DETECTOR (FID), PHOTOIONIZATION DETECTOR (PID), OR AN AQMD APPROVED ORGANIC VAPOR ANALYZER (OVA) CALIBRATED IN PARTS PER MILLION BY VOLUME (PPMv) OF HEXANE (IF A CALIBRATION AGENT OTHER THAN HEXANE IS USED IT SHALL BE CORRELATED TO AND EXPRESSED AS HEXANE).

  9. WHENEVER THE VOC CONCENTRATION AT THE OUTLET OF THE FIRST STAGE CARBON ADSORBER IS 25 PPMv OR GREATER AS HEXANE, OR WHEN VOC BREAKTHROUGH HAS OCCURRED AT THE FIRST STAGE ADSORBER, THE SOIL VAPOR EXTRACTION AND TREATMENT SYSTEM (SVE) SHALL BE IMMEDIATELY SHUT DOWN, AND THE FIRST STAGE ADSORBER REMOVED FROM SERVICE. THE SVE SHALL NOT BE RESTARTED UNTIL THE SECOND STAGE ADSORBER HAS BEEN RELOCATED TO THE FIRST STAGE ADSORBER POSITION, THE THIRD STAGE ADSORBER RELOCATED TO THE SECOND STAGE ADSORBER POSITION, AND A NEW THIRD STAGE ADSORBER WITH FRESH ACTIVATED CARBON IS INSTALLED. RECORDS OF THE SERIAL NUMBER OF EACH CANISTER OF ACTIVATED CARBON, THE DATE EACH IS INSTALLED, THE POSITION IN THE SERIES (FIRST, SECOND, OR THIRD STAGE POSITION), AND THE DATE REMOVED FROM SERVICE SHALL BE MAINTAINED TO DOCUMENT COMPLIANCE WITH THIS CONDITION.

  10. A GRAB SAMPLE SHALL BE COLLECTED AT THE INLET AND OUTLET OF THE FIRST STAGE CARBON ADSORBER DURING THE FIRST WEEK, AND AT LEAST ONCE PER MONTH THEREAFTER. THE SAMPLES SHALL BE ANALYZED FOR TOTAL VOC IN PPMv AS HEXANE, AND ANALYZED FOR BENZENE, ETHYLBENZENE, TOLUENE AND XYLENES, SPECIATED IN ACCORDANCE WITH AQMD APPROVED METHODS.

  11. THE BENZENE CONCENTRATION AT THE OUTLET OF THE FIRST STAGE CARBON ADSORBER SHALL NOT EXCEED 2 PPMv.

  12. THIS EQUIPMENT SHALL NOT BE USED TO TREAT VAPORS CONTAINING HALOGENATED COMPOUNDS, NOR ANY TOXIC COMPOUNDS LISTED IN AQMD RULE 1401 (AS AMENDED ON 3-17-2000) OTHER THAN BENZENE, TOLUENE AND XYLENES.

  13. THE ACTIVATED CARBON USED IN THE ADSORBERS SHALL HAVE A CARBON TETRACHLORIDE ACTIVITY NUMBER OF NOT LESS THAN 60% AS MEASURED BY ASTM METHOD D3467-99 OR A BUTANE ACTIVITY NUMBER OF NOT LESS THAN 23.5% AS MEASURED BY ASTM METHOD D5228-92 (1996).

  14. SPENT CARBON REMOVED FROM THE SYSTEM SHALL BE STORED IN CLOSED CONTAINERS PRIOR TO REMOVAL FROM THE SITE.

  15. RECORDS SHALL BE KEPT AND MAINTAINED TO PROVE COMPLIANCE WITH ALL CONDITIONS ON THIS PERMIT. THE RECORDS SHALL BE KEPT ON FILE FOR AT LEAST TWO YEARS AND MADE AVAILABLE TO AQMD PERSONNEL UPON REQUEST.