Where to dispose of frying oil? 

Frying oil is an oil derived from cooking certain foods by immersion in a fryer or pan. Generally speaking, oil comes from a variety of sources, such as animals via duck fat, or plants like sunflower, peanut or olive oil. Heated to high temperatures, these oils cook food quickly and evenly, giving it a crispy texture.

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

When to dispose of or replace frying oil?

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

 Used frying oil is frequently used over and over again. However, it eventually loses all its properties. Knowing when it's time to replace it is crucial, both for our dishes and for the environment. Signs of an oil that needs replacing include a dark color, a rancid odor and a poor ability to fry effectively. An oil is considered altered if it shows signs of browning, marked for the most part by the appearance of a stable foam absolutely distinct from the classic bubbling that is noticed when food is introduced. Frying oil unsuitable for use may also manifest itself as :

  • The presence of increased viscosity 
  • Excessive density 
  • Smoke emission 
  • Reduced crunchy texture 
  • The presence of an unusual odor 
  • Lack of bubbling when food is introduced 

In general, if you've used the oil to cook richly-flavored foods such as fish, it's best to replace it after one use. For less flavorful foods, you may consider reusing it a few times after careful filtering. Filtering consists mainly in removing debris after frying, to prevent it from carbonizing during another frying session, which could accelerate the degradation of the bath.

 Then it's important to replenish the oil and keep it cool. Frying oil should preferably be stored in a well-sealed container, or in a deep fryer with a lid. It should also be kept away from light and air to prevent oxidation. Oil that has been kept in a deep fryer for more than two or even three weeks without being used once should not be used. We also advise against using the same frying oil more than 4 to 6 times.

Frying oil: an environmental hazard 

Ignorance about how to dispose of used frying oil can have devastating consequences for our environment. When oil is flushed down drains or toilets, it can clog filters and cause blockages as well as obstructions, necessitating costly unclogging work. Worse still, if it reaches watercourses, it can create a film of oil that prevents oxygen from entering the water, endangering aquatic life and disrupting the ecosystem.

One liter of used oil covers a thousand square meters of water surface, which considerably alters the oxygenation of existing flora and fauna, thus threatening the biodiversity of watercourses. Wastewater treatment plants are not spared the consequences of discharging used cooking oil into the sewage system either. They are no longer able to perform their role efficiently, as the bacteria responsible for wastewater purification are also asphyxiated. It is therefore imperative to adopt responsible management practices to dispose of used frying oil.

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Where to dispose of frying oil? 

Disposing of frying oil down the drain often seems like a quick and efficient solution, but it has disastrous consequences. Grease or oil congeals and accumulates in the pipes. They clog up in the pipes, causing blockages or backing up into watercourses. As oil and water are immiscible, a greasy film forms on the surface of the water, contaminating drinking water and harming the biodiversity of aquatic life. Fortunately, to alleviate this problem, there are more responsible ways of disposing of frying oil. There are a number of appropriate options for disposing of used frying oil.

At the waste centre 

Used frying oil is non-hazardous biowaste, but particularly polluting when disposed of carelessly. Their triglyceride composition makes them very difficult to break down, and also explains the fact that they clog most of the components they come into contact with. One of the safest and most responsible ways of disposing of frying oil is to take it to a waste disposal center. Many depots accept used cooking oil and have appropriate systems for its management. In this case, used cooking oil is treated as household special waste, or placed with hazardous waste for more specific treatment. In this way, it is either incinerated or recycled for reclamation by approved companies. Be sure to store the oil in an airtight, leak-proof container before dropping it off at the waste disposal center.

In the household waste bin 

 Cooking oil that is unsuitable for use is approved for the household garbage bin if it is in small quantities, less than 31%. centilitres. However, it should be allowed to cool and then transferred to a sealed plastic container before disposal. Otherwise, frying oil improperly stored or disposed of directly in an ordinary rubbish bin can cause leaks and spills, creating messes and waste mismanagement that could have been avoided. So you don't need to go anywhere. However, it is advisable to dispose of used frying oil in the non-recyclable waste garbage can, i.e. the grey bin. Be careful, however, about the quantity of oil you put in the bin, which should be minimal. If you don't, the garbage collectors responsible for collecting your household waste may refuse it if they consider the quantity of frying oil to be too great.

At a specific collection point organized by local authorities 

Many local authorities have set up special collection points for used cooking oil. These collection points are usually located in strategic places, such as supermarkets or recycling centers, 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 dispose of frying oil? 

There are a number of bad habits to be avoided when it comes to managing used cooking oil. For the sake of protecting and preserving the ecosystem, cooking oil should not be disposed of in a number of places that may seem convenient, but are actually harmful to the environment.

In a sink or toilet 

Pouring frying oil down the sink or toilet may seem convenient, but it's a practice you should absolutely avoid. Sewers are not designed to handle oil, and it can cause costly and harmful blockages. Disposing of cooking oil down the drain is strictly forbidden, as is merging it with wastewater. Apart from the nuisance it causes to the aquatic and plant world, cooking oil can clog your pipes and cost you money. What's more, it significantly impedes wastewater treatment.

In compost or vermicompost 

Although some types of vegetable oil are biodegradable, frying oil is not suitable for compost, especially if it has been used to fry animal-based foods. It can cause odor and decomposition problems in the compost. It's absolutely counterproductive, as it slows down the decomposition mechanism of your green waste while attracting pests like rodents. Frying oil has a tendency to impair air circulation, which is absolutely not the desired effect when it comes to compost. It is therefore not advisable to use this method to dispose of your unused cooking oil.

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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 soils, preventing the circulation of both water and air. As a result, asphyxiated soil is no longer able to support plant growth. Oil in the garden prevents decomposition in the soil, so the supply of nutrients to plants is no longer effective. To this end, throwing the bottom of your saucepan or used cooking oil into your garden is absolutely not recommended.

Recycling used cooking oil 

Recycling used frying oil can be a sensible way of reducing its environmental impact. Contrary to popular belief, frying oil is an integral part of household waste that can be recycled. You can reuse your oil at least five times, provided you filter it beforehand 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 of doing so.

To make detergent or laundry detergent 

Frying oil can be transformed into detergent or into detergent biodegradable. Some companies offer processes for converting oil into environmentally-friendly cleaning products. You can also do it at home if you wish. You'll also need protective equipment such as goggles and sturdy plastic gloves, as you'll be handling caustic soda.

To make candles 

With a little creativity, you can turn used frying oil into candles. This process requires additional materials, but it's an innovative way of reusing oil. All you need are some pretty glass containers, a wick for the candle with its metal holder, and essential oils of your choice. The principle is to place the wick with its metal support in the container, centering it carefully. You can also wrap the wick around a wooden stick to make it easier to hold. Then pour your pre-filtered frying oil three-quarters of the way into the container, add a few drops of essential oil and your candle is ready.

 With certain companies 

Some specialized recycling centers collect used cooking oil and transform it into biodiesel or biofuel for agricultural use. This option gives the oil a second life, while helping to reduce carbon emissions. Other companies recycle used oil for use in public lighting systems. Some restaurants will take back household frying oil, so you can contact the ones nearest you for more information.

What should I do with my oil bottle?

Oil bottles can usually be recycled by simply dropping them off at the appropriate collection points. Check your local recycling guidelines to ensure the best disposal of the plastic bottle. Also, these plastic bottles need to be thoroughly rinsed before you can dispose of them. They should not, however, be disposed of with household waste, but rather in recyclable waste bins, particularly green bins.

Frying oil is biowaste and must be disposed of in accordance with well-defined principles. So be aware of the laws and regulations in your area concerning the disposal of frying oil, and take an active part in safeguarding the ecosystem. Some jurisdictions may have specific requirements on how to deal with this particularly polluting fatty substance. By adopting responsible frying oil disposal practices, you are helping to protect the environment and preserve natural resources.

To find out more about the subject of frying oil and all the little things you can do to improve your daily life, we recommend reading the excellent article by Blog Ecologya veritable toolkit for ecology at home!

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