Printer manufacturer HP has been demonstrating its efforts to improve the environmental impact of its products by highlighting the processes it uses to recycle empty ink cartridges.

The company invited PC Mag to take a tour of its facility at Smyrna, Tennessee – which at 80,000 sq ft, is the biggest of the many such plants the firm operates around the world.

HP estimated that in 2011 alone, the company reused 28.6 million pounds of plastic in its new ink cartridges, while since implementing its Planet Partners programme in 1991, around 446 million ink cartridges have been returned to the firm to be reused, with more than two billion new printer supplies containing material recovered through its processes.

The initiative, which sees HP work with outside enterprises to recover the consumables, now runs in 50 countries and no parts from cartridges collected are sent to landfill.

Representatives from HP told PC Mag that even after factoring in the cost of transportation for the empty cartridges and the materials that are extracted from them, the recycling programme has a smaller environmental footprint than would be generated by creating cartridges from entirely new materials.

The publication observed that after supplies are received, sorted and recycled by the manufacturing facilities, they are cleaned and transported elsewhere for use in a variety of products.

Items processed at Smyna, for example, are dispatched to Montreal, where they are combined with plastic recovered from other sources, such as used drinking water bottles, to create new cartridges that HP claims are just as good as those manufactured from original parts.

When these consumables are used up, the process can be repeated, creating what HP refers to as a 'closed loop' and ensuring no materials are unnecessarily sent to landfill.

As well as the plastics used in the cases, two companies have also come up with a new use for leftover printer toner that remains in old cartridges.

New Zealand-based firms Toner Recycling and Enviropaints have teamed up to convert the unused toner into paint that can be used outdoors on buildings and fencing, the Sunday Star-Times reported.