Why Recycle Used Cooking Oil?

grease recycling in New Jersey and Pennsylvania

There are many reasons to recycle used cooking oil from your restaurant, from protecting the environment to protecting your employees. If you’re in New Jersey, Pennsylvania or Delaware, give D&W Alternative Energy a call.

What does used cooking oil do to the environment?

Petroleum oils and used cooking oils that aren’t properly recycled have similar environmental impacts, according to the EPA. That is they can be toxic, destroy animal and fish habitats, and coat animals and plants, all of which produces oxygen depletion and destroys food supplies. The oils can destroy breeding animals. 

Spilled oil can harm living things because its chemical constituents are poisonous. This can cause skin and eye irritation. If animals inhale or consume the oils, it can wreak havoc on their insides. 

The oil can also reach natural water reserves, which puts the lives of aquatic and marine creatures at risk. Oil can also smother some small species of fish or invertebrates and coat feathers and fur, reducing birds’ and mammals’ ability to maintain their body temperatures. If cooking oil reaches the water, it can kill aquatic life forms and birds by coating them with a thick layer of sludge. This reduces their ability to breathe, which can lead to them choking to death.  

Some people think they can dump used cooking oil in the ground or in their garden, but improperly disposed of cooking oils clog municipal water ways, block pipes, and create expensive and foul smelling backups into restaurants and homes. This dumping can also cause contaminated oils to leech into aquifers contaminating the water, making it undrinkable and harming both animals and waterways.

Despite these problems, when processed correctly, used cooking oil can actually help the environment, rather than harm it. Used cooking oil needs to be recycled into useful products and particularly products such as biodiesel and renewable diesel, which, when used in place of regular diesel, greatly reduce emissions of greenhouse gases.

Greenhouse Gases

Greenhouse gases are gases in the atmosphere that trap heat. We need some greenhouse gases to keep Earth warm enough for human habitation. The gases act like the glass of a greenhouse. Scientists agree, however, that the dramatic increase of greenhouse gases since the industrial revolution are intensifying climate change. Natural made greenhouse gases include carbon dioxide (CO2), methane, nitrous oxide and water vapor. C02 levels have increased 50% since the industrial revolution.

Three industrial fluorinated gases – hydrofluorocarbons (HFC), perfluorocarbons (PFC) and sulphur hexafluoride (SF6) – come from industrial processes and do not occur in nature. They are present in small concentrations in the atmosphere, but are extremely effective at trapping heat. 

How many times can you reuse cooking oil before recycling it?

Given the high and rising cost of cooking oil it is logical to ask how many times you can reuse cooking oil? The answer is not simple because the useful life of cooking oil is impacted by:

Is the oil frothing or smoking? That means it’s time to change the oil. Still, the best way to determine when to change your oil is to test your cooking oil to determine if it is still capable of producing high-quality cooked foods. Overusing cooking oil can have a negative effect on product quality and restaurant profits. It makes your food taste bad, burned or soggy. A couple of limp french fries and fishy tasting chicken and you’ve lost a customer who will tell seven other people who won’t ever become customers.

Fresh cooking oil is composed almost exclusively of triglycerides. As oil is used, exposure to air, water, and heat begin to break down the triglycerides into alcohols, free fatty acids and other polymers. Measuring FFAs (Free fatty acids) and TPM (total polar material) are the best ways to test the quality of the oil. There are test strips for FFA measurement, color guides to match to a sample of your oil, and handheld devices which measure TPM. Test strips are cheap and have an 80% accuracy rate. The color comparison is easy and cheap but is very subjective which can lead to using bad oil or throwing away good oil too soon. The handheld TPM device is 90% accurate but the device can run as high as $500 and needs periodic calibration.

Where does used cooking oil go?

You should always recycle used cooking oil to prevent damage to the environment and reduce  greenhouse gases. Used cooking oil recyclers with sucker trucks arrive at restaurants and collect the oil for transport to an intermediate recycling facility. At the facility, used cooking oil is filtered to remove suspended substances such as burned foodstuffs. The oil is heated to evaporate water content. Recyclers carefully measure to determine FFA levels and MIUs (moisture, insolubles and unsaponifiables). Biodiesel producers won’t buy the oil unless it is less than 10% FFA and less than 2% MIU.

At this point, the recyclers may sell the oil to companies that use it as an ingredient to make biodiesel, animal feed, plastics such as polypropylene, cosmetics and sustainable aviation fuel. Because of the demand for fuels that produce fewer greenhouse gases, along with government policies that reward cleaner burning fuels, most used cooking oil gets recycled into fuel.

How do you make Biodiesel?

At a biodiesel plant, the oil is heated to remove water and then undergoes a process called esterification in which the FFA is converted into chemical compounds called esters. These esters are then transformed into biodiesel and glycerol by-products.

How do you make Renewable Diesel?

Renewable diesel is made from used cooking oil through a series of processes called hydrotreating and hydroprocessing which are similar to the process of “cracking” crude oil into gasoline and diesel in a traditional oil refinery. Cracking crude oil is the process of breaking heavy hydrocarbons into lighter hydrocarbons using heat, pressure and catalysts.

Renewable diesel, while not identical to traditional diesel, is so close that the EPA considers it a drop-in fuel replacement for regular diesel. Some biodiesel is blended into renewable diesel for its greater lubricity.

What is Sustainable Aviation Fuel (SAF)?

SAF is made by blending kerosene with renewable hydrocarbons. SAF produces 80% less C02 than traditional jet fuel over its production and use lifecycle. The EPA has defined pathways along with critical tracking to ensure that the biomass used to make SAF is made according to the EPA approved pathways.

The EPA provides valuable RIN credits to producers to make and sell SAF consistent with those pathways. There are always those willing to take a shortcut and introduce biomass that was not collected as used cooking oil (or stolen) and traceability along every step of the pathways is critical to maintaining the integrity and quality of SAF.

What is the difference between biodiesel, renewable diesel and SAF?

The blog link above explains the differences in some detail. In summary, biodiesel is made from renewable sources such as used cooking oil and is a fuel that is blended with regular diesel in different proportions (B5 to B100) as a replacement for regular diesel. Renewable diesel is made from renewable sources but undergoes a different process to become renewable diesel. Renewable diesel undergoes a process where oxygen is removed with the aid of hydrogen. Then the straight chain hydrocarbon is branched, giving it properties similar to regular diesel. Other impurities like sulfur are removed in the process. It is considered a drop-in fuel and can replace regular diesel without blending. SAF, the newest entrant, is made from a variety of renewable sources and is a replacement for jet fuel.

Read more about used cooking oil collection.

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