EN Rx Chemical Oxidants Treat Free Product

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Courtesy of EN Rx

CASE STUDY
#0116
G
ATE 1204 PILOT, SEBRING, FL

SITE OVERVIEW

Active gas station in Sebring, FL FDEP Site Number: 8629375

CONTAMINATION

Gasoline contaminants in ground water

Two site features that have long been a detriment to chemical oxidant treatments at sites have recently been overcome by EN Rx. These are free product treatment and shallow water tables. Generally, chemical oxidants are so violently reactive to free product that it becomes dangerous to both workers and site peripherals, not to mention it may be counterproductive. Shallow water tables generally create a situation where short-circuiting is certain to happen and it becomes difficult to inject the needed quantities into the ground. The Gate 1204 site was treated using our Continuous Injection System which allows the slow injection of activated reagent which can eliminate mounding and short-circuiting and also control cash flow by not requiring large initial chemical injections. The system is only possible because of our proprietary activation which lasts more than 90 days on the surface without becoming dangerous. Similarly, it is the same activator that allows us to attack free product level concentrations with minimal or no measurable heat generation.

HISTORY

- Leaking Underground Storage Tank (UST) had contaminated an area at this active gas station.
- Shallow water table (1 -2 ft) created a difficult cleanup scenario.
- Free Product (FP) was measured in wells since 2007 (apparent discharge) in three wells around tank farm. .

PRE-CLEAN DATA

  • In addition to the wells with measurable free product, 7 wells were above NADCs (2 are deep wells, 24' and 27' bls).

  • The soils are sandy with some silts in the shallow zones.

  • BTEX contaminant mass is difficult to estimate based on the immeasurable amount of free product around the tank farm.

    More treatment is required beyond this pilot study and the immeasurability prohibits total mass reductions calculations.

    REMEDIATION ACTIVITIES (PILOT)

  • The injection lasted 3 months and inject a dosage of 14,000 pounds of oxidant.

  • The Continuous Injection System operated efficiently (

  • No excessive heat was found due to the reaction and all three FP wells are now being sampled as non FP wells.

  • The plume size was minimized for future treatments (four wells were reduced to NADCs, including both deep wells).

  • The interpretation of the exact reduction is also difficult due to fluctuations in the water table. And thus we won't focus on the analytical results of this particular study, but would rather focus on the successful implementation in a very shallow water table, without short-circuiting and no adverse effects from free product treatment.

    Case Study 0117: Groundwater Treatment Results

    BTEX Concentration

    MW-3

    MW-4

    MW-16

    MW-18

    MW-19

    MW-26

    MW-35

    MW-36

    DMW-1

    DMW-4

    Pre (Jan 2011)

    1.4 U *

    292 *

    34.4 **

    FP

    1906**

    163*

    280

    1952

    21

    179

    Post (Dec 2011)

    174

    413

    332

    25,000

    23,900

    56

    8.5

    0.9

    6.3

    7.4

    Percent Reduction

    -

    -

    -

    uncalc

    -

    66%

    97%

    100%

    55%

    95%

    Treatment Result

    liberation

    liberation

    FP rem.

    FP rem.

    FP rem.

    none

    Wells that did not indicate a significant change in concentration which were all below NADCs prior to treatment are: MW-5, MW-11, MW-21, MW-23, MW-24, MW-27, MW-32, DMW-2, DMW-3, DMW-5, DMW-6.
    Well that were below GCTLs and not sampled are: MW-2, MW-6, MW-12, MW-13, MW-22, MW-25, MW-28, MW-29, MW-30, MW-31, MW-33, MW-34 * Historically, much higher results (water table fluctuation may add confusion)

    ** Historically (only one event prior to baseline) this location measured free product
    EN Rx, Inc. PO Box 270586, Flower Mound, Texas, 75027 Phone 832-250-1700

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