Lift-Station with a flow of 80,000 gallons per day. Problem with solid grease buildup on equipment and walls. They were able to control using a combination of high strength degreasers, but it was expensive and pushed grease downstream to the wastewater treatment plant.
The city could not add aeration or other mixing devices to the lift-station which is often successful when combined with added grease degrading microbes. Given the short-residence time and high levels of grease entering the station from upstream lines, we decided to combine several technologies to prevent grease buildup in the station and to not simply push large amounts of grease downstream to the wastewater treatment plant as is done by adding most d-limonene or other sewer line degreasers.
The final formulation we developed for the application contained a concentrated blend of microbial spores associated with grease degradation and biosurfactant production (which is required for efficient insoluble grease biodegradation). To enhance the speed of biodegradation, we added extra biosurfactants, enzymes, micronutrients, and a low percentage of biodegradable detergents (to help maintain a homogenous product and help increase the grease/water interface where bacteria grow).
The goal was for initial activity from the enzymes and surfactants to provide ideal conditions for most rapid bacterial growth of the added grease degrading microbes. The result would keep the grease from solidifying on the lift-station walls and equipment. The microbes would begin beta oxidation of the insoluble fatty acids (grease) that cause problems downstream at the wastewater treatment plant. As the number of carbon atoms decrease, the fatty acids become more available to microbes and convert from FOG to easily degradable soluble BOD.
For the past 60 days, we have stopped using degreasers with manual cleaning and only used the new formulated microbial product. With dosing being done via a metering pump and spray nozzle above the water line, the entire lift station is being treated. During the trial solid grease buildup has been eliminated and the lift station is operated as designed. No problems have been noted in the downstream wastewater treatment plant
Erik Rumbaugh has been involved in biological waste treatment for over 20 years. He has worked with industrial and municipal wastewater facilities to ensure optimal performance of their treatment systems. He is a founder of Aster Bio (www.asterbio.com) specializing in biological waste treatment.
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