Where to dispose of cooking oil? 

Frying oil is an oil that is derived from cooking certain foods by immersion in a fryer or pan. Generally, the oil comes from different sources such as animals via duck fat or even plants such as sunflower, peanut or olive oil. These oils, heated to high temperatures, allow foods to cook quickly and evenly while giving them a crispy texture.

The tantalizing smell of fried foods can turn any meal into a delicious experience. However, behind these tasty foods lies a question that is of vital importance for our environment: what to do with used cooking oil? Although proper recycling of cooking oil is often overlooked, the oil can have a major impact on sewers, waterways and the overall ecosystem if disposed of improperly. Find out all the information you need here on where to dispose of frying oil.

When to throw away or replace frying oil?

Frying is a high-temperature dehydration process that represents a very old food cooking technique. It consists of immersing food in boiling oil or fatty substances which act as a medium for heat transfer. The ultimate objective of frying is above all to create a crust while changing the color, texture and flavor of the food.

Used cooking oil is frequently used multiple times. However, it ends up losing all its properties after a while. Knowing when it’s time to replace it is crucial, both for our dishes and for the environment. Signs of an oil that needs to be replaced include a dark color, a rancid odor, and poor ability to fry effectively. An oil is considered spoiled in the event of browning, marked for the most part by the appearance of a stable foam absolutely distinct from the classic bubbling which is noticed when food is introduced. Frying oil that is unsuitable for use can also manifest itself by:

  • The presence of increased viscosity
  • Excessive density
  • The emission of smoke
  • Reduction of crispy texture
  • The presence of an unusual odor
  • Lack of bubbling when introducing food

In general, if you have used the oil to cook foods rich in flavor, such as fish, it is best to replace it after one use. For less fragrant foods, you may consider reusing it a few times after careful filtering. The latter mainly consists of the elimination of debris after frying in order to compensate for their subsequent carbonization during another frying, which could accelerate the degradation of said bath.

Then, it is important to top up the oil level and keep it cool. Frying oil should preferably be stored in a tightly closed container or in a fryer that has a lid. It must also be placed away from light or air to prevent any oxidation process. Oil kept for more than two or even three weeks in a fryer without having been used once should not be used. It is also not recommended to use the same frying oil more than 4 to 6 times.

Frying oil: a danger for the environment

Ignorance about how to dispose of used cooking oil can have devastating consequences for our environment. When oil is flushed down drains or toilets, it can clog filters and cause clogs as well as blockages, requiring very expensive unclogging work. Worse yet, if it reaches waterways, it can create an oil film that prevents oxygen from entering the water, endangering aquatic life and disrupting the ecosystem.

One liter of used oil covers an average of a thousand square meters of water surface, which considerably alters the oxygenation of existing fauna and flora, thus threatening the biodiversity of waterways. Wastewater treatment plants are not as spared from the consequences of discharging used cooking oil into pipes. In fact, they are no longer able to perform their role efficiently, because the bacteria responsible for purifying wastewater are also asphyxiated. It is therefore imperative to adopt responsible management practices to dispose of used cooking oil.

Where to throw your cooking oil?

Flushing cooking oil down the drain often seems like a quick and effective solution, but it has disastrous consequences. Fat or oil congeals and builds up in the pipes. They clog the pipes, causing blockages or backflow into waterways. Since oil and water are not miscible, this will cause the appearance of a greasy film on the surface of the water which contaminates drinking water and harms the biodiversity of aquatic life. Fortunately, to overcome this problem, there are more responsible ways to dispose of cooking oil. For this purpose, several suitable options for disposing of used frying oil are offered.

At the recycling center

Used cooking oil is a non-hazardous biowaste, but particularly polluting when it is disposed of casually. Their triglyceride composition makes them really difficult to break down and also explains the fact that it clogs the majority of the elements they touch. One of the safest and most responsible methods of disposing of cooking oil is to take it to a recycling center. Many recycling centers accept used cooking oil and have appropriate systems for its management. In this case, used cooking oil will be treated as special household waste or it will be placed with hazardous waste for more specific treatment. Thus, it is either incinerated or recycled to be used by approved companies. Be sure to store the oil in an airtight, leak-proof container before taking it to the recycling center.

In the household waste bin

Cooking oil that is unsustainable for use is approved in household waste bins if they are in small quantities, less than 31 centiliters. However, you will need to let it cool and then transfer it to a tightly closed plastic container before throwing it away. Otherwise, cooking oil improperly stored or thrown directly into a regular trash can can cause leaks and spills, creating messes as well as poor waste management that could have been avoided. So you won’t need to travel. However, it is advisable to throw used cooking oil into the non-recyclable waste bin, i.e. the gray bin. However, be careful with the amount of oil you put in the waste bin, as it should be minimal. Otherwise, the garbage collectors responsible for collecting your household waste could refuse it if they consider that the quantity of cooking oil present is too large.

At a specific collection point organized by local authorities

Many local authorities have set up specific collection points for used cooking oil. These collection points are usually located in strategic locations, such as supermarkets or recycling centers, thus facilitating the recycling process. Many regions offer municipal collection programs or specific drop-off points for cooking oil. Check with your municipality to find out what options are available near you.

Where not to throw away your cooking oil?

Several bad reflexes should be avoided when it comes to managing used cooking oil. Indeed, for the sake of protection and preservation of the ecosystem, cooking oil should not be thrown away in a certain number of places which may seem practical, but are detrimental to the environment.

In a sink or toilet

Pouring cooking oil down the sink or toilet may seem convenient, but it is a practice that should absolutely be avoided. Sewers are not designed to handle oil, and it can cause costly and harmful blockages. The disposal of cooking oil via pipes is strictly prohibited, as is the merging of the latter with waste water. Aside from the nuisance it causes in the aquatic and plant world, cooking oil risks clogging your pipes and making you spend money. In addition, it significantly hinders the treatment of wastewater.

In compost or vermicompost

Although some types of vegetable oils may be biodegradable, cooking oil is not suitable for composting, especially if it has been used to fry animal foods. It can cause odor and decomposition problems in compost. This is an absolutely counterproductive method, because it slows down the decomposition mechanism of your green waste while attracting pests such as rodents. Frying oil tends to impair air circulation, which is absolutely not the desired effect when it comes to compost. It is therefore not recommended to use this method to dispose of your unused cooking oils.

In the garden

Cooking oil should never be poured directly into the garden. It can alter the soil and harm plants by hindering their ability to absorb water and nutrients. Oils as a whole clog the soil by preventing the circulation of both water and air. The soil being asphyxiated is no longer able to ensure the development of your plants. Oil in the garden prevents decomposition in the soil and therefore the supply of nutrients to plants is no longer effective. To this end, throwing away the bottom of your pan or used cooking oil in your garden is absolutely not recommended.

Recycle used cooking oil

Recycling used cooking oil can be a wise option to reduce its environmental impact. Contrary to popular belief, cooking oil is an integral part of household waste that can be recycled. Already, you can reuse your oil at least up to five times by making sure to filter it first using a coffee filter for example. When it becomes unfit for use, you can then recycle it for more useful purposes. Here are some creative ways to do it.

Make detergent or laundry detergent

Cooking oil can be made into biodegradable detergent or laundry detergent. Companies offer processes to convert oil into green, environmentally friendly cleaning products. You can also do it at home if you want. Furthermore, you must have protective equipment such as glasses and sturdy plastic gloves, because you will have to handle the caustic soda.

Make candles

With a little creativity, you can turn used cooking oil into candles. This process requires additional equipment, but it is an innovative way to reuse oil. All you need is pretty glass containers, a wick for the candle with its metal support, essential oils of your choice. The principle consists of placing the wick with its metal support within the container, taking care to center it correctly. To make it hold more easily, you can wrap it around a wooden stick. Then pour your previously filtered frying oil into three-quarters of the container before adding a few drops of essential oil and your candle is ready.

From certain companies

Some specialized recycling centers collect used cooking oil to transform it into biodiesel or biofuel for agricultural use. This option gives the oil a second life while contributing to the reduction of carbon emissions. Other companies recycle used oil with the aim of using it to power lighting systems in public places. Some restaurateurs accept the collection of household cooking oils, so you can contact the restaurants near you to find out.

What should I do with my bottle of oil?

Oil bottles can generally be recycled, simply drop them off at the appropriate collection points. Check your area’s recycling guidelines to make sure you dispose of the plastic bottle better. Furthermore, these plastic bottles must be rinsed thoroughly before you can throw them away. However, they should not be thrown away with household waste, but rather in recyclable garbage bins, particularly green bins.

Frying oil is biowaste that must be thrown away following well-codified principles. So be aware of the laws and regulations in your area regarding the disposal of cooking oil in order to actively participate in saving the ecosystem. Some jurisdictions may have specific requirements on how to deal with this particularly polluting fatty substance. By adopting responsible practices for disposing of cooking oil, you help protect the environment and preserve natural resources.

To find out more on the subject of frying oil and all these little things to improve your daily life, we recommend reading the excellent article by Ecology Blog, a real tool kit for ecology at home!