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Field case study  /  Hydrocarbon bioremediation

Soil remediation at an
oil well casing facility

Pipe coating and pressure testing yard  ·  Twenty acres  ·  2004 to 2005

Twenty acres, a peak of 115,280 mg/kg, and a loan that depended on finishing. Treated in place in under two months.

115,280
mg/kg TPH
at the worst sample
982
mg/kg TPH
at the same point after
20 acres
Treated in place
no excavation

The site

An oil well casing and tubular company that had run pipe coating and water pressure testing across a twenty acre property for years, with very little to stop the materials reaching the ground.

Coating materials and solvents were used in large volumes and the waste was routinely washed onto the ground or spilled. In places the soil was under a thick black oily residue, and areas larger than an acre had standing pools. Wastewater was being pumped out through hoses into nearby drainage ditches. Testing put TPH between 2,830 and 80,000 mg/kg across the site, with one sample at 115,280.

Why the clock mattered

A jumbo loan was contingent on the remediation being completed and on ongoing environmental practices being put in place, inside a short window. The site assessment began in September 2004. The remediation itself did not start until late January 2005.

What we did

Hot spots were identified by sampling, then the ground was cleared of debris and graded. Across the twenty acres the work used up to thirty five drums of a biodegradable surfactant concentrate and up to 175 pounds of a hydrocarbon-degrading microbial blend in total. Five pounds of dry microbes went into each drum of concentrate, and each drum was then diluted with roughly 350 gallons of water and pumped over the ground until the surface was saturated.

The soil was tilled and ploughed after application, then re-tilled as needed, usually a couple of times within the month, with water added to keep the moisture up. Some areas needed a second treatment. The worst single acre took roughly six drums of concentrate and thirty pounds of microbial blend across two treatments.

Worst sample
Before treatment
115,280
mg/kg TPH
After treatment
982
mg/kg TPH
From 11.5 times over the benchmark to 10 times under it
Second worst
Before treatment
80,220
mg/kg TPH
After treatment
891
mg/kg TPH
From 8 times over the benchmark to 11 times under it
The benchmark above is the Railroad Commission of Texas cleanup level for crude oil in non-sensitive areas, one per cent by weight, or 10,000 mg/kg. Quoted for scale only. Cleanup criteria vary by state, by programme and by site, and the governing criterion for this site is not stated here.
All twelve baseline samples against their follow up
Sample29 September23 March
Total petroleum hydrocarbons, mg/kg
Sample 0111,300187
Sample 023,640265
Sample 03115,280982
Sample 04Under 5,970104
Sample 05Under 2,93093
Sample 0615,33023
Sample 079,540Under 20
Sample 08Under 5,40023
Sample 10Under 3,54070
Sample 1180,220891
Sample 1274,700667

Every one of the twelve baseline points finished below 1,000 mg/kg, and seven of them finished below 300.

What this does and does not show

It shows that a heavily contaminated working yard can be brought down across twenty acres, in place, inside two months, using tilling and moisture to do a large share of the work.

It does not show that every acre responds alike. Contamination here varied by a factor of forty between sampling points, application rates varied with it, and some areas needed treating twice. This site was also sampled twice rather than monitored continuously, so the figures are two points in time, not a curve.

How the work was done. Delivered through our partnered Houston microbiology and genomics laboratory, which has run this class of work for more than thirty-five years. RAD Microbes LLC was founded in 2024. Contamination levels were measured by laboratory TPH testing on 29 September and again on 23 March, using Texas method TX 1005.

Start with a discovery call

Every site is different, and a short conversation tells us far more than a sample does. Talk us through what you are dealing with and we will tell you honestly whether biology is the right answer for it. If it is not a fit, we will say so on the call.

Call +1 949 333 9072