Fats, oils & grease are more than a system operator’s nightmare
Bacon! Who does not love bacon? Collection system operators, that’s who.
With or without wipes, fats, oils and grease (FOG) are the bane of collection system operators worldwide. As we hear about fatbergs in London and New York, there is a growing need to control how FOG moves through our systems.
The first step to FOG control is trying to prevent its entrance into the system in the first place. Best practices for communities are great in theory, if they are followed. Grease traps and grease interceptors need to be maintained properly to work. All this depends on making sure that someone cares as much about the sewer lines as the operator.
When FOG enters the sewer lines, it is similar to bad cholesterol entering our blood stream. Any place it can find to deposit, it will because it can. This is true at major collection points, such as lift station and pump station wet wells. Buildup leads to clogging and clogging leads to sanitary sewer overflows. Municipalities install equipment to keep it suspended and mixed. Aerators are added to keep it from settling and also to add oxygen. Mixers are added in an effort to keep the top from crusting, fighting a losing battle until someone calls for the vac truck, and the operators get geared up for confined space entry and dirty work.
Chemical and biological treatments have been developed to reduce the frequency of these cleanings. Bacterial additives can reduce the biomass, however, even bugs can only eat so fast. Degreasers and dishwashing liquid can help disperse it.
Newer systems, such as mechanical well washers that work from above the water line, can reduce the frequency of cleanings and the need for multiple pieces of equipment, but they must be used system wide for the best effect. In the end, the grease still ends up at the wastewater treatment plant where it adds to the overall biological oxygen demand loadings, grease foaming and solids bulking. So, is there an answer on how to prevent the next fatberg? Give up bacon? Teach the community to make candles out of bacon grease and olive oil? Create a biofuel refinery? OK, that one may have merit.
We need to be realistic; the American culture is obsessed with bacon and fast food is not going anywhere, so it is up to us to teach the responsible disposal of FOG in our communities. Educating the community members is the only way to ensure that the FOG cholesterol does not enter into our sewer bloodstream. Enforcing regulations requiring grease traps and grease interceptors can help a community reduce its FOG greatly. Spill plans and disposal permits are important to controlling FOG. Pretreatment of industry waste and using technology such as dissolved air flotation can reduce the load added from industrial waste.
Just like the war on disposable wipes, communities must take a strong stand on how they dispose of FOG. Slogans like “down the drain, clogs a vein” can be effective in reminding people to dispose of grease in their solid waste receptacles. Hand out grease scrapers as a reminder.
Clever ideas can make an impact. Be proactive in the approach to how you prevent build-up. Well washers in the wet wells can keep the solids and FOG moving through the system, so they do not deposit in collections. Adding a bacterial element will help in the digestion and breakdown of the biomass, reducing the load at the headworks.
FOG can overwhelm bacteria systems at a headworks. Just like humans who can get lazy on a steady diet of fat, oil and grease, FOG fed to the wrong bacteria will make them react the same way a human couch potato does. Systems must look at where and how to properly dispose of FOG to ensure that one solution does not cause another problem.
This is not a utility problem without a solution, it is a community problem with a community solution. Utilities can only do so much to mitigate the FOG. The best solution is active prevention.