Many industrial processes generate wastewater with significant levels of fats, oils and grease (FOG), and if this FOG reaches treatment systems and equipment then it can wreak havoc and cause expensive inefficiencies. 

Not only is FOG harder than other wastewater materials to degrade biologically, but it can also congeal and deposit on surfaces of pipes, pumps, tanks, digesters, monitoring equipment and other treatment infrastructure. 

Deposits like these reduce treatment effectiveness by creating blockages, clogging and choking treatment systems, and reducing the sludge digestion ability of microorganisms used in wastewater treatment processes. It is also one of the more expensive pollutants when discharging to a municipal sewer. 

The best way to deal with FOG is to capture it early on in the treatment process, before it has a chance to pass through sensitive equipment and technology.

Talk to our experts to find out how. 

Fat, oil and grease are common organic materials, and many industrial sectors and processes work with sources of FOG. As a result, FOG can be a prominent component of industrial wastewater, either through process water or wash water. The food and beverage industries are particularly prone to FOG, but they are by no means the only sectors that can be impacted by this kind of material. 

As its name suggests, FOG comprises fatty substances. In chemical terms, this generally means long-chain organic molecules; in more everyday terminology, this refers to generally food-based items such as butter, dairy products, plant oils and animal fats, but it also refers to lubricants and hydraulic oils that may be present in or on machinery or transport vehicles. 

As such, any industrial process that incorporates plant or animal products is particularly exposed to sources of FOG, but the fact that FOG also encompasses lubricants and other machinery oils means that every facility almost certainly has to deal with some degree of FOG in its wash water or wastewater. 

The most significant adverse impact that FOG has on industrial wastewater treatment technologies is its tendency to settle, accumulate and deposit on the surfaces of various equipment.

This creates clogging—and, over time, potentially even total blockage—that reduces the effectiveness of treatment equipment, and reduces the facility’s overall wastewater treatment efficiency. Filters, screens, pipes and pumps are particularly prone to blockages and clogs of this nature. 

In the UK, recent news stories have revealed how bad this problem can become. Enormous “fatbergs” have been discovered in the nation’s sewers—huge deposits of FOG that have congealed around other materials to create impediments and even total blockages of underground sewer pipes. 

While it is possible to address FOG at various stages of the wastewater treatment process—enzymatic digestion is one such way—it is invariably preferable to capture it as early as possible in the treatment process.

Skimmers and gravity traps are relatively simple solutions, though they have limitations, including a high inspection and maintenance burden. A more effective approach is to use dissolved air flotation, or DAF. This involves aerating wastewater at high pressure, then reducing the pressure to induce tiny bubbles that attach to FOG particles and other suspended matter to generate a scum that can be removed and disposed of. 

There are companies that refine or repurpose FOG, so industrial businesses that remove and separate FOG properly may be able to turn this from waste into an additional line of revenue.