The famous blue bins are the ultimate symbol of the National Recycling Programme. 

If you live in an HDB or in landed property, you have probably used one of these bins for recycling.  While some condos and office buildings use segregated recycling bins, the iconic blue bins are the recycling option most familiar to Singaporeans. 

Blue bins are usually provided by one of the big Public Waste Collectors.

Single Stream aka Commingled

Blue bins are the starting point for Singapore's single stream recycling system. Meaning that all different types of recyclables (paper, metal, glass, plastic) are commingled (ie put in the one bin) and then trucked to a sorting plant known as a Material Recovery Facility ("MRF").

At the MRF, the material is sorted, baled, and then sold to companies that can recycle those materials.  

Anything that cannot be sold/exported is sent for incineration.