If you need to recycle your printer cartridges, you can bring them to libraries in Singapore and drop them off in the "Project Homecoming" recycling bins.
The below is taken from Canon's website:
What is Project Homecoming?
Project Homecoming is the first joint-brand initiative to bring ink and
toner cartridges recycling to the community. Project Homecoming is now
jointly-led by Canon and Epson, and supported by National Environment
Agency and National Library Board. With this project, we aim to create
awareness on the recycling of ink and toner cartridges, and to engage
local communities to do their parts for our environment."
Do you accept cartridges from non-participating brands?
Project Homecoming accepts ink and toner cartridges from all
participating and non-participating brands, all cartridges will be
collected by our authorised recycler partner.
How does the cartridge recycling process work?
The used ink and toner cartridges will be dismantled
into different components by our authorised recycler partner, Tes-AMM
(Singapore) Pte Ltd.
Plastic and metal, the main components of a cartridge, will be recycled
into new plastic and metal products, thereby minimising waste and the
need for new raw material. Non-recyclable parts will be properly
incinerated.
These recycling processes will help to minimise waste and pollution
while, at the same time maximising resource recovery.
It's really great that we have such recycling bins conveniently located all around us!
(Source: http://www.canon.com.sg/ecoproject/recycling-program.html)