Microbes for sustainable remediation of pollution by CL Solutions

After the removal of a leaking tank, Petrox was used to treat the ground water contaminated with residual petroleum constituents. Petrox was injected into the ground water through 28 injection points covering a plume area of approximately 6,300 square feet. Three treatments of Petrox were recommended and implemented on June 18, September 11, and November 1, 2002.

Remediation Design

Prior to bioaugmentation, 100 pounds of ORC was added to provide supplemental oxygen for the bioremediation. After verifying the dissolved oxygen concentration was more than 1.0 milligrams per liter (mg/L), the site was ready for bioaugmentation.

During the first injection, 10 drums of Petrox were injected to cover the full plume. As the area of contamination decreased, less Petrox was injected. Five drums were injected in a focused application on September 11 and November 1, 2002.

Quarterly monitoring was completed during and after the inoculation to determine the bioremediation results. The cleanup goals were achieved in the source area after the first inoculation; however, the contamination was still present in the down gradient wells. The cleanup goals were achieved in the down gradient monitoring wells after the third injection, but there was subsequent rebound. The cleanup goals were achieved and maintained once the full impact of the Petrox bioremediation was reached throughout the plume.

Results

Please refer to the two tables below for the ground water monitoring results, which are in micrograms per liter (µg/L).

MW-7 Source Area
Date	Benzene	Toluene	Ethylbenzene	Total Xylenes	Naphthalene
6/12/2000	5	46	18	90	24
6/13/2001	39	272	167	526	26
3/14/2002	21	19	102	266	39
6/5/2002	ORC Added
6/18/2002	10 Drums of Petrox Added
7/14/2002	<1.0	<1.0	<1.0	<2.0	<1.0
9/11/2002	<1.0	<1.0	<1.0	<2.0	<1.0
9/11/2002	5 Drums of Petrox Added
10/7/2002	<1.0	<1.0	<1.0	<2.0	<1.0
11/1/2002	5 Drums of Petrox Added
12/2/2002	<1.0	<1.0	<1.0	<2.0	<1.0
1/9/2003	<1.0	<1.0	<1.0	<3.0	<5.0
4/17/2003	<1.0	<1.0	<1.0	<2.0	<1.0

MW-8 Down Gradient
Date	Benzene	Toluene	Ethylbenzene	Total Xylenes	Naphthalene
6/12/2000	2	72	21	109	39
6/13/2001	14.8	677	207	1292	113
3/14/2002	71	1198	357	2408	193
6/5/2002	ORC Added
6/18/2002	10 Drums of Petrox Added
7/15/2002	19	515	170	690	39
9/11/2002	<1.0	3.7	3.8	16.4	<1.0
9/11/2002	5 Drums of Petrox Added
10/7/2002	6.4	2.3	4.7	23.8	15
11/1/2002	5 Drums of Petrox Added
12/2/2002	38	515	95	460	10
1/9/2003	<1.0	<1.0	<1.0	<3.0	<5.0
4/17/2003	<110.0	1060	285	1120	65
4/29/2004	<1.0	<1.0	<1.0	<1.0	<1.0
9/1/2004	<1.0	<1.0	<1.0	<1.0	<1.0
12/1/2004	<1.0	<1.0	<1.0	<1.0	<1.0
3/21/2004	<1.0	<1.0	<1.0	<1.0	<1.0

After one year of post-closure monitoring showed that the cleanup goals were maintained. The site was issued a No Further Action Order on September 13, 2005 by the Environmental Protection Division.

Orange County Fire and Rescue Station 81 Orlando, Florida

Site Summary

Remediation Design

Results