June 2, 2021
There are always plenty of reasons and opportunities to remove gas and oil stains from concrete. For instance, concrete driveways, garages, and bridges are often the victims of vehicle gas and oil leaks. In addition to dealing with the bad appearance, contractors must make sure concrete surfaces are thoroughly clean and free of all contaminants before applying a waterproofing membrane. A recent test demonstrates MCI®-2061 in action under the microscope and builds confidence in this “green” cleaning product for concrete oil stains.
How Green Cleaners Work
MCI®-2061 works by a dual mechanism. Biodegradable surfactants disperse oil droplets and perform the initial cleaning. If properly applied, MCI®-2061 spores then germinate into active microorganisms and perform secondary cleaning by actually digesting hydrocarbons. This activity increases as time goes on. In fact, spores that remain in the substrate after rinsing may continue to degrade residual hydrocarbons that were not removed in the initial cleaning process.
MCI®-2061 Efficacy Demonstration
To demonstrate surfactants and microorganisms at work in MCI®-2061, the product is typically applied to a small area, and before-and-after results are compared to validate the cleaning efficacy. However, the easiest and fastest way to show decomposition of organic matter is to measure COD (chemical oxygen demand) reduction in a sample. To demonstrate this, three samples of MCI®-2061 were prepared for testing of biodiesel digestion. All samples were diluted with water at a ratio of 1:100 and were also examined under the microscope.
Sample #1 (control) – MCI®-2061 without bacteria or biodiesel
Sample #2 (control) – MCI®-2061 without bacteria but with biodiesel added
Sample #3 – MCI®-2061 with bacteria and biodiesel
| Sample ID | COD t=0 (mg/L) | COD t=1 week (mg/L) | COD reduction (mg/L) | COD Reduction % |
| MCI®-2061 NB Control | 17,040 | 17,760 | 720 | +4.23% |
| MCI®-2061 NB | 22,780 | 23,080 | 300 | +1.32% |
| MCI®-2061 | 21,760 | 13,900 | -7860 | -36.12% |
COD, a measure of contaminants in the solution, dropped by 36.12% over this timeframe, while COD increased slightly in the two control samples not seeded with bacteria.
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