Confidential Site with excess nitrate in ground water

Nitrogen is one of the elements required for microbial cell growth. Excess nitrate in ground water, however, can be harmful. Denitrification is the process by which select organisms can convert nitrate into nitrogen gas. Bacteria that mediate denitrification, utilize nitrate as a metabolic terminal electron acceptor under anaerobic conditions. While Petrox® normally metabolizes organic compounds using oxygen as an electron acceptor, the organisms in Petrox® DN can utilize the same metabolic pathway to remove excess nitrate from ground water under aerobic or anaerobic conditions.

Petrox® DN is a consortium of Pseudomonas putida, which are well known for their metabolic diversity. These naturally-occurring organisms are non-pathogenic and are manufactured under food-grade protocols. Petrox® DN contains a guaranteed cell count of 109 cfu/ml. The high population of denitrifying organisms accelerates the removal of nitrate and removes the guesswork from project management.

Laboratory Validation

A bench-scale treatability study demonstrated the high rate of denitrification by Petrox® DN. At a population of 107 cfu/mL, Petrox® DN removed nitrate at a rate of 17.1 mg/L/hr under anaerobic conditions.


Field Validation

Petrox® DN was applied to nitrate contamination in ground water two locations. In field application 1, after two monthly treatments, Petrox® DN reduced the nitrate concentration by 65%. In the second field application, after just one Petrox® DN application the bioremediation removed 50% of the nitrate in 56 days.

ind_site_conf_2_2 ind_site_conf_2_3


Petrox® DN is provided freeze-dried for ease of use. Once hydrated Petrox® DN can be introduced into the ground water through injection points or well. Once in the aquifer a carbon source is added to support the population growth. Under favorable conditions the organisms will flourish with a high capacity to remove nitrate, until the nitrate is depleted. For additional information contact CL Solutions at 513-475-6625.

Pest Control Company Located in Florida

Bioremediation of Pesticides Using Petrox®  to Meet Part per Trillion
Remediation Goals


Petrox  bioremediation successfully reduced pesticide contaminant concentrations in ground water at a pest control company in Florida. Dieldrin and heptachlor epoxide were found in ground water at concentrations exceeding state drinking water standards, which were measured in parts per trillion. After three applications of Petrox, the pesticide concentrations decreased more than 99% in three source area monitoring wells.

Geology and Hydrogeology

The site is set in the Florida Panhandle where thick coastal sediments characterize the shallow geology. The sediments underlying the site were fine-grained sand and silt more than 60 feet thick. The depth to the water table was approximately 45 feet.


Pesticides were found in shallow soil and ground water at the property. Pesticides had also migrated off the source property in the ground water. The pesticide concentrations in the ground water were relatively low, but exceeded state regulatory standards by orders of magnitude. Prior to remediation, the maximum concentration of dieldrin in ground water was 9.8 µg/L, while the remediation goal was 0.002 µg/L. Heptachlor epoxide was present in the source area ground water at 0.68 µg/L, with a remediation goal of 0.200 µg/L. The remediation challenge was to reduce the contamination levels from the very low initial concentrations to meet even lower remediation goals.

Remediation Design

Petrox bioremediation was direct injected into the ground water in three applications approximately 30 feet apart. During each injection 275 gallons of hydrated Petrox were injected into the three locations over a 15 foot thick interval. Monitoring wells in the treatment area were sampled to assess the progress of the remediation. Three injections were completed on 60 day intervals. The following charts show the contaminant concentration trends in the monitoring wells. The vertical red line shows the initiation of bioremediation.

dieldrinconcentrationtrend heptachlorepoxideconcentrationtrend


Despite the low initial concentration and dispersed contamination, Petrox bioremediation significantly reduced the contaminant concentrations over the full treatment area.  The heptachlor epoxide concentrations met the remediation goals in all monitoring wells in the treatment area. The maximum dieldrin concentration was reduced from 9.8 µg/L to 0.22 µg/L. After three treatments and less than 9 months, the dieldrin and heptachlor epoxide concentrations were reduced by more than 99%. The product cost for treatment was less than $15,000. Petrox provided an efficient, cost-effective remediation solution for the site.

Bioaugmentation to Reduce Ammonia, Nitrate and Organics in Wastewater

Case Study: Improving Poultry Wastewater Treatment

Site Summary

Petrox DN® bioaugmentation was implemented at a poultry processing plant to deal with a recurring problem of excessive ammonia levels in wastewater discharge. Petrox ND® bioaugmentation reduced the organic carbon load in the wastewater and converted the ammonia to nitrogen gas. Within 48 hours of treatment the ammonia levels in the wastewater were reduced to acceptable levels and discharge limits were maintained.

Nature of the Problem

Wastewater treatment requires the treatment of a variable waste stream with limited control over the volume and concentration of the raw material and only moderate control over the operating conditions. The goals for organic wastes include the removal of organic pollutants, reducing the total organic load, reducing nutrient concentrations including nitrogen, and odor control. Removal of ammonia and nitrogen compounds are typically achieved by a two- step process of nitrification of the ammonia and denitrification of the nitrate. The autotrophs Nitrosomas sp. and Nitrobacter sp. are typically involved in these steps. As autotrophs these microbes use carbon dioxide instead of organic carbon to build cells, organic wastes are not treated by this process.

The Pseudomonas sp. in Petrox DN® oxidize the organic carbon wastes converting it to cell mass, carbon dioxide and water and generating stored cellular energy.  Simultaneously, the Pseudomonas sp. in Petrox DN® remove ammonia and nitrogen by utilizing these compounds as a nitrogen source for cell growth and electron acceptors during the consumption of the organic wastes. The benefit of Petrox DN® bioaugmentation is the removal of both the organic waste, nutrients and elimination of ammonia odors.

Pseudomonas sp. are also cold water tolerant, so Petrox DN® can be used year round under most under natural conditions.


The plant generates 0.85 million gallons of wastewater per day with ammonia levels of 80 to 120 ppm. The wastewater after primary treatment and equalization flows into a 7.5 million gallon anaerobic lagoon and subsequently four sequencing batch reactors (SBRs). At the end of the settling cycle, the supernate discharges to a receiving stream.

Bench-scale laboratory studies showed that nitrate could be removed at a rate of 17 mg/L/hr under aerobic conditions and at a rate of 12 mg/L under anaerobic conditions. TOC could be removed at a rate of 45 mg/L/hr. Petrox DN® bioaugmentation was initiated in the aeration basin and the SBRs.

After less than 48 hours the wastewater met and maintained the wastewater discharge limits.

Petrox® Bioaugmentation in Bedrock

Case Study: Petroleum Remediation in Central New Jersey


Petrox® bioaugmentation was implemented at a petroleum remediation site in Morris County, New Jersey to destroy residual petroleum compounds in ground water. The impacted ground water was in bedrock fractures under and down gradient of a former UST location. The UST was removed and an oxygen release compound was added to the ground water to stimulate bioremediation. However, residual contamination persisted and Petrox® bioremediation was implemented to remove the residual low concentration found at the site.

Geology and Hydrogeology

The bedrock surface was fairly close to the ground surface and the first ground water encountered upon drilling at the site was within the bedrock. Impacted ground water was contained within the fractures near the bedrock surface in a zone estimated to be 40 feet thick.


Low concentrations of benzene, xylene, ethylbenzene and toluene were present in ground water at and down gradient of the former UST cavity. The area of proposed treatment was 3,600 square feet.


Petrox was applied in two monthly applications of 8 units each. One unit of Petrox® is a 55-gallon slurry with a microbial concentration of 109 cfu/ml. ORC socks were installed in treatment wells to provide an oxygen source for the petroleum metabolism.

The monthly Petrox® injections were on May 29, 2009 and June 26, 2009. Post -treatment samples were taken on June 10, 2009 and May 4, 2010. The following table shows the contaminant concentration treads in the treatment area.



The treatment was successful in reducing the BTEX concentration at the site. However, the increase in concentrations after the first treatment showed that there were residual petroleum constituents in the source that was not reflected in the pre-treatment sampling. Petrox® microbes were detected in all of the bedrock sampling points as far as 30 feet down gradient of an injection point. Overall the treatment verified the effectiveness of Petrox® bioaugmentation in fractured bedrock.