Compostable Paper Cups
What is a compostable paper cup?
By definition a compostable paper cup must degrade within 12 weeks under commercial composting conditions.
Normal cups are made using a fine lining of polyethylene (PE) on the inner wall, which ensures that when the cup is produced it is then watertight, but to make a cup compostable you have to use other methods of manufacture, but at the same time make sure the cup is functional in the same way as the normal PE cup. This is not an easy task
So how is this done?
The most common way of doing this is to use a starch based compound, called Polylatic Acid or PLA for short. This is derived from corn starch and it is then used as a substitute for the PE lining.
So which is best?
The answer to that is a difficult one.
Firstly are you going to just put the cup in your rubbish bin? If so the chances are it’s going to end up in a landfill with all the other items, possibly with thousands of tons of other rubbish on top of it. If that’s the case you might as well buy normal cups as no cup is going to degrade under these circumstances, even if its the greenest cup in the world. So you have to make sure the recycling path you choose does what it says on the tin to ensure that they are processed correctly. If this is done either of the two different means of making a cup biodegradable can be used.
Then there is the ethics of this.
By that I mean should we worry about compostability if the current cups can be recycled?
Should we use PLA, which is a starch derived form corn, when that corn could be used to feed the poor? A difficult question that I do not have an answer to, but here at PCF at the current moment we are exploring both avenues using the PLA technology, whilst exploring and developing alternatives to using PLA.
Finally the cost….
PLA cups are a lot more expensive than normal cups . In some cases this can be up to 30% more but with the right method of disposable the cost benefit outweighs the extra charges.
The debate will continue and more work has to be done to ensure that the disposal of these items meets the best environmental standard.
I hope that this article helps you appreciate the complexities of this issue and of course we always welcome your comments.