Fat, oil, and grease is produced as a by-product of cooking foods. These include vegetable oils, meats, and dairy products. FOG is a common source of contamination in food service establishments such as restaurants, takeaways, and pubs, and it has the potential to enter the sewer system during cleaning processes. When FOG is hot, it enters sinks and drains easily; however, as FOG cools, it solidifies, blocking and damaging sewer pipes and causing problems during the wastewater treatment process. The presence of FOG in the wastewater system causes a variety of problems in the drains, wastewater collection system, and wastewater treatment plants.
How do you remove oil and grease from wastewater?
When fats, oils, and grease enter the drainage system, they congeal and harden in the pipe as they mix with food and other sanitary waste. Sewer overflows can occur as a result of FOG-related blockages due to reduced capacity or burst drain and sewer pipes, as well as foul odors. This could have serious environmental consequences, such as land contamination and a risk to public health.
To avoid blockages, problematic sewer lines necessitate frequent jetting and chemical dispersal of FOG. Unfortunately, this can cause issues with downstream lift stations and sewage pumps.
Challenge: FOG in the wastewater treatment plant
When FOG reaches the wastewater treatment plant, it can cause additional problems. Grease degrades more slowly biologically than other common components of municipal sewage.
FOG can also congeal and accumulate on the surfaces of settling tanks, digesters, pipes, pumps, and sensors. Grease can partially clog screens and trickle filter systems. It can clog sludge pumps. It can significantly reduce the activity of sludge-digesting microorganisms. Excessive foaming, increased sludge volume, and Nocardia bacteria that form flocs are also issues.
Treatment solutions for FOG in wastewater
FOG is treated in three ways. The most effective solution is to stop FOG at the source so that it does not enter the wastewater system. It should then be removed from the sewer system before it reaches the wastewater treatment plant. Finally, FOG can be dealt with at the wastewater treatment plant. Traditional methods include introducing bacteria or enzymes to attack FOG, whereas newer methods involve stimulating existing bacteria, causing FOG to degrade.
Elimination at the source
The most effective way to control FOG is to control it at the source. To separate FOG from the restaurant's sullage, many Food Service Establishments use a passive grease interceptor unit installed in the kitchen greywater outlet. The brown grease accumulated in the trap or GI must be properly disposed of. Grease interceptors must be emptied and cleaned on a regular basis to remain effective.
Removal from drains
If it has accumulated in the sewer system, it is necessary to manually remove it. The locations will be more prone to FOG blockages due to their proximity to residential, commercial, or industrial areas; the characteristics of the sewer pipe, such as its diameter or condition; and the characteristics of the sewer network, such as the number of inflows and effluent volume. When pipe repairs or changes to cleaning and maintenance are ineffective, the only option may be manual collection, which requires a large number of people and poses health and safety risks.
Disposal at the WWTP
Bioaugmentation is a technique that uses bacteria-forming enzymes to break the bond between glycerol and fatty acids. Biodegradation, a process in which bacteria and microorganisms consume fat, sugar, and starch wastes, can then be used to dispose of these elements. Long-term bioaugmentation usually necessitates the regular injection of specialized organisms, as introduced organisms cannot keep up with the system's main population.
Rather than introducing foreign enzymes and bacteria, newer treatment methods focus on stimulating existing bacteria to break down FOG.To stimulate the indigenous bacteria population and accelerate natural biodegradation, this approach employs optimized fermentation-based yeast proteins, micronutrients, and specialized surfactant chemistry dosed at a few parts per million. This biocatalytic effect has the potential to provide a number of operational benefits at the wastewater treatment plant, including reduced sludge production, increased nutrient uptake, and improved settlement.
Netsol Water are the experts for providing better treatment options for water and wastewater. We have wide range of products and we can customize many as per customer’s requirements. We can provide solutions that are trouble-free and cost-effective.