When I worked for my former employer, we used to work quite a lot on wastewater and animal facilities that all had to deal with odor. We sold a complex probiotic culture to these and other businesses. This mixture of 60 microorganisms includes lactic acid bacteria, yeasts, and photosynthetic bacteria. I became proficient in teaching people how to use the product and anticipate what it would do for their situation. Occasionally, I would run into a scenario where I could not explain exactly how the product would do this or that, but its effects were consistent. One of these situations was when an engineer asked me how these microbes might have been able to remove odor from the air. He insisted that there were only two ways to remove odor from that air; the first was using some chemical, and the other was a physical filter. He pretty much laughed at me when I described a nearly instant reduction in ammonia or hydrogen sulfide. My initial goal was to get him to try the product, not to argue over the how or why of the matter.
We set up a simple apparatus at a lift station with several restaurants at the edge of a plaza. The apparatus I had included a small dosing pump, a 55-gallon barrel with the product in it, and a high-pressure fogging pump with six 20-micron nozzles and a timer. The line with the fogging pump was zip-tied to the inside rim of the manhole cover. Once installed, I dropped a long polyline from the dosing pump into the manhole. The line was about 2 feet above the highest level markings on the sides of the lift station, so about 8 feet above the running wastewater. (I have since lost the picture of this setup.)
Next, we tested the hydrogen sulfide gas (H2S) amount using an OdaLog. The initial reading was 2,500 ppm. Of course, we know it smelled bad, but we had no clue it was that high. I turned on both pumps, and we left the OdaLog hanging on a hook in the lift station. OdaLogs can record measurements of H2S for up to 14 days, giving you the highest, lowest, and average readings through the time it is left in the sewer line or wherever it is placed. When I turned that fogger on, the H2S went to 0 ppm almost instantly, proving that microbes (at least our mix of microbes) could control odorous gases. The question remains: how? Perhaps the ‘how’ is explored below.
Photosynthetic bacteria are capable of removing hydrogen sulfide (H2S) from a gaseous state through chemosynthesis, a metabolic process similar to photosynthesis. Still, instead of using light energy to convert carbon dioxide and water into glucose and oxygen, these bacteria use energy from oxidizing inorganic compounds like hydrogen sulfide to produce organic molecules.
Photosynthetic bacteria that engage in chemosynthesis are often found in environments with low or no light, such as deep-sea hydrothermal vents, where they utilize chemical compounds like hydrogen sulfide as an energy source. Here's a simplified overview of how this process works:
1. Energy Source: Photosynthetic bacteria that perform chemosynthesis use hydrogen sulfide (H2S) as their energy source instead of light.
2. Oxidation: These bacteria oxidize hydrogen sulfide (H2S) using enzymes. The oxidation reaction releases energy, which the bacteria capture and use to synthesize organic compounds.
3. Carbon Fixation: Like in photosynthesis, the bacteria fix carbon dioxide (CO2) from the surrounding environment to create organic molecules like sugars. The energy produced by the oxidation of hydrogen sulfide aids in this.
4. Organic Compound Production: Using the energy derived from the oxidation reaction and the carbon fixed from carbon dioxide, the bacteria synthesize complex organic compounds that serve as energy and nutrient sources.
5. Waste Products: Unlike photosynthesis, where oxygen is produced as a byproduct, chemosynthesis often produces sulfur compounds as waste products. These sulfur compounds may be deposited around the bacteria or released into the environment.
It's important to note that chemosynthesis is an alternative metabolic process to photosynthesis. It allows certain bacteria to thrive in environments where light is unavailable but suitable chemical compounds are abundant. These bacteria play a crucial role in ecosystems like deep-sea hydrothermal vents, where they form the base of the food chain by providing a source of organic matter for other organisms.
In summary, photosynthetic bacteria that perform chemosynthesis can remove hydrogen sulfide from a gaseous state by oxidizing it and using the released energy to synthesize organic compounds. This does not fully explain how the probiotic mix would control hydrogen sulfide or ammonia in an almost instant process; however, it gives a glimpse of what could be happening in the dark areas inside a lift station or sewer line.
Have you ever tried using EM to control odors? How fast did it work?