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Is paper biodegradable? Paper is a material that we use every day but not all paper is created equal when it comes to composting. So, how do we know and identify which paper is compostable?
There are a number of factors that determine compostability. Paper is an organic material and therefore biodegradable. However, while in theory it can be composted, in practice it’s not always compostable. This is because of technical definitions of compostability. This means some types of paper or paper products can’t be composted at all at home.
Most paper, including glossy paper, is compostable. The same holds true for most printed papers. Most printing ink is biodegradable and as such printed paper like magazines and newspapers is perfectly compostable. The main exceptions to this are papers that have been coated in substances such as wax. In these cases, that type of paper is generally not compostable.
Biodegradable Actually Mean
We have used the term “biodegradable” and in short, it is a word used to describe a material that has been designed to break down in the composting process. The problem is that often under pressure from industries governments have stretched its meaning.
In reality, we have two extremes and a large gray area in between. Paper as a raw product is highly biodegradable as it can decompose in a few months or less. This contrasts with synthetic polymer plastic items which are made from oil and can’t be broken down by microbial bacteria even after being placed in landfills for hundreds of years.
However, there are paper products, such as tea bags or some crimped paper coffee filters, that contain small amounts of adhesives and or plastics that can be legally marked as biodegradable yet would take up to a hundred years to fully decompose. When looking at specialty papers or products that appear to be predominantly made of paper it is important to find out exactly what is in them before you add then to your compost bin or pile.
Factors that Impact the Compostability of Paper
In truth, paper varies so much that it’s impossible to say with any certainty that all paper material is safe for composting. Some papers are recycled, bleached, or unbleached; some are coated with wax or plastic; others may have inks or dyes added to them before they’re rolled into a sheet. Some papers even have adhesives on their surface that could cause problems when composted.
In general, though, there are three elements that impact the compostability of paper and relate to how the paper is constructed, if there are any coatings applied to the paper, and finally, whether the paper is printed. The extent of the impact varies from preventing composting to affecting the rate of decomposition.
The Material Used In Paper’s Construction and the Effect on Compostability
The most important factor is what from and how the paper is constructed. Paper can be constructed from numerous different plant materials, from wood pulp and other vegetable fibers such as cotton and flax as well as straw, jute, manilla hemp, and esparto.
Paper is made from a combination of water, fibers, and chemicals. Broken down the cellulose fibers are turned into pulp. Whilst all of these materials are organic and are thus biodegradable, the type of fiber used to make the paper will determine how quickly it decomposes in a compost pile
The majority of paper though is still made of or originates (if recycled) from wood pulp. There are though, different processes that wood fiber can go through to make the pulp. Newspapers are generally made from wood fibers in which the lignin has not been removed. This will cause them to break down more slowly than office paper, where it has been removed, in your compost pile.
Coatings Applied to The Paper
The second issue that affects compostability is coating. For magazines and brochures, you will often notice the glossy paper cover helping draw you in. These covers have been coated to produce this effect. Whether these coatings contain plastics will determine if the covers can be composted.
The truth is it is difficult to know. You will often see recycling symbols printed on the magazine but that doesn’t mean that it is compostable. If it tells you that it is coated with a biodegradable biopolymer such as PLA then it might be able to be composted. Otherwise, or if in doubt, it is best to remove the glossy paper covers recycle this part, and compost the main part of the magazine
The answer is yes, you can compost most paper with ink on it. However, there are some factors to consider before making a decision about whether or not your printed paper is recyclable from an environmental standpoint.
First of all, printing inks are biodegradable and are often made from water-soluble dyes which do get broken down over time by microorganisms (beneficial bacteria). However, if you have any doubts about whether or not your printer’s inkjet cartridges or toner would be suitable, maybe you have bought non-branded or ink refills from dubious origins, then it might be best not to compost them and use them in your garden.
Secondly, the age of the printed paper will also have an impact on whether you should or should not compost. This is because although modern inks are biodegradable and have been for a considerable time, this is unlikely to be the case with the fifty-year-old newspapers you might find bundled up in your grandpa’s old house.
Types of Paper Products and Specialist Papers
It is very important to know the difference between a paper that can be composted and paper that cannot. A lot of specialist papers have coatings, adhesives, and plastics in them. Some of these will compost, some are marked compostable but aren’t, and some shouldn’t even be considered.
Parchment paper is made from traditional wood pulp and vegetable fibers that has been processed by passing it through a bath of sulphuric acid to add additional properties such as heat resistance. Sometimes this is part of the process and on other occasions, it is achieved by using an additional coating.
There are two types of parchment paper, brown and white. The difference between the two lies in the processing with brown being unbleached and generally uncoated.
White parchment paper goes through a beaching process and is often coated in silicone or fluorine to provide a nonstick property. While these coatings can prevent your food from sticking when cooking they also make it difficult for the paper itself to break down in your compost pile. This is due to the fact that the paper’s components are difficult to separate.
The brown paper is usually biodegradable but check with the manufacturer whether it applies to industrial composting or is suitable to be included on your compost pile.
In general, paper that is covered in grease, fats, or various vegetable oils should not be composted. Although small amounts of vegetable oil can be composted, it will slow down the decomposition process of the pile. The primary reason though, to avoid soiled paper, is that it can attract vermin and smell as it decomposes.
If you have a closed compost bin you may be okay but, in general, soiled paper is best disposed of outside of the composting process
The appearance and texture of wax paper are comparable to those of parchment paper, but its performance is not the same. The wax coating on the paper, consists of a film of paraffin wax, making the product nonstick and water resistant but NOT heat resistant.
It can be found in food raps or at the bottom of pizza boxes and can be tempting to throw in the compost bin. However, in terms of composting, paraffin being a petroleum-passed product is not compostable and should instead be thrown away and not even included in your recycling paper box.
You may be wondering the same thing about paper towels. Are they compostable? The answer is mostly no as many manufacturers use non-compostable materials in their paper towel products to help make them more durable and long-lasting.
Although these paper towels can be made from virgin or recycled paper, they are typically coated in a plastic adhesive which makes them difficult to break down in your compost pile. This makes these types of paper towels unsuitable for composting, and they should be recycled along with other plastics.
There are some manufacturers who have created compostable versions of their paper towels. However, you need to be careful when considering composting these. The product might be marked ‘ Compostable’ but actually, that doesn’t mean on your backyard compost pile but at an industrial composting facility. Before adding them it is advisable to check with the manufacturer if it is compostable or home compostable.
You will undoubtedly have noticed that the majority of receipts are printed on thermal paper. The problem with thermal paper though is that it contains either Bisphenol-A (BPA) or Bisphenol-S (BPS) to make it print.
These chemicals are especially toxic. It has been shown that not only are they harmful to the reproductive systems of both humans and wildlife but that studies have also associated these chemicals with attention deficit and even obesity problems.
Chucking the odd thermal receipt on your compost heap is unlikely to cause too many issues but if you had a few rolls of the material that you want to dispose of you should not put them on your compost pile.
In many countries, the use of single-use plastic bags has either been phased out or has been heavily regulated. This has seen a renaissance in the use of the old ubiquitous brown paper bag. These are compostable but you should watch out for reinforced areas around the handles. In practice, instead of worrying about what is in them, just rip these parts out before shredding them for composting.
How to Include Paper in Your Composting
Composting paper isn’t just a case of throwing it onto your compost pile. To compost it effectively you need to prepare and combine it with other layers of compost that are going into the pile.
The first thing you’ll need to do is shred your paper into small pieces, about 1/4 inch wide and long. This makes it easier for the microorganisms to break down the material or for worms and other soil animals to digest the cellulose in it. You can use a food processor or simply tear strips from larger sheets with your hands.
Shredded paper can also be used in specialized composting processes such as high-fiber composting. It can also be extensively used in vermicomposting, which has certain benefits over more traditional forms of composting and where it makes great bedding in worm bins.
Start by laying down a thin layer of brown compost material, such as leaves, wood chips, or dead plant matter, and on top of this add a layer of shredded paper. Then add a layer of green materials such as food waste, like vegetable peelings, grass clippings, or other organic material with higher nitrogen content.
Then it is a question of repeating the layers, organic material, another layer of shredded paper, and then more green materials. As a top layer, you should look to finish with a layer of leaves or other brown materials.
When building your pile pay attention to the carbon-to-nitrogen ratio. Paper is considered a brown material and has a carbon-to-nitrogen ratio (C/N) of between 150-200:1. You should look for your pile to have an overall C/N ratio of around 30-40:1 depending on the composting process you are following.
Water the compost heap to add some moisture and, depending on whether you are engaged in active or passive composting, look to aerate the pile by turning it two or three times a week to build up heat inside the pile, Alternatively, just follow a cold composting process leave the pile, perhaps turning it once every few weeks and allow the organic material to breakdown.
If you are hot composting and actively turning, you should have finished compost within six to twelve weeks whereas with the more passive method it could take four to six months or longer.
Summary: Is Paper Compostable? – Can You Compost Paper with Ink?
There are many different types of paper that can be composted. In the main, the compostability of paper is related to how it was made and what type of fibers are used in its construction. If you’re wondering whether or not a paper is compostable its use case is generally the key.
It is though, important to note that different types of paper decompose at different rates, which is likely to impact your composting. The decomposition rate depends on many different factors including the type of paper being made at that moment and how it was made in the past, if old.
Outside of this, the main thing to remember is that if it’s coated in some way, you should carefully examine whether the coating is conducive to composting!
- Science Direct, Nitrogen in the Marine Environment (Second Edition), 2008: Lignin Decomposition