The activated carbon found in the filter refill, once used, can be reused to prevent odours, mould and for composting.
How to use it?
First, you should rinse the used charcoal grains or the "charcoal block" (i.e. the compressed charcoal) with cold water. Then dry it thoroughly, ideally outdoors, as this will work better than drying it indoors.
Preventing odours / bad smells
Put the dry charcoal in a sock and leave it where you want it to be odour-free: the fridge, the bathroom, in the car or in drawers - even in your old slippers! Or in your pet's bed. It will absorb the smell. Every few months you can repeat the process with another used charcoal block.
Prevent mould (e.g. in bathrooms).
Like the process above, put it in a sock and leave it in the area where the mould is growing. Ideal in climates / areas with high humidity.
When the activated charcoal stops doing these functions (it is no longer fighting the mould or absorbing the odour), it can be composted. If it is in compressed "carbon block" form, such as one of our EcoPro or EcoPro Compact filters, grind it up and mix it into compost or soil; it also works very well in potted plants. The carbon will not only passively settle into the soil, it will aerate it and retain water.
The refills are made with activated carbon and a binder. The binder is inert (it will decompose) but is not certified for composting. Also, if unfiltered tap water has contaminants in it, it is possible that the carbon block has accumulated contaminants and they may be released into the soil of the plants. Our experience is that this should not affect this because the same contaminants are also obtained when watering with unfiltered tap water directly.