​What would encourage consumers to sort their recyclables more carefully? Terradona came up with a powerful rewards-based program that allows users to earn incentives every time they dispose of correctly-sorted recyclables. The company turned to Leti, a CEA Tech institute, to develop a novel system capable of characterizing glass. Designed to be installed directly on recycling drop-off containers, the system had to be suitable for existing containers, reliable, affordable, and resistant to impacts and dirt.

The solution developed, which is protected by several patents, comes in the form of a ring-shaped apron that is installed in the opening of an existing container. A striker is automatically armed when a user disposes of waste and strikes the waste as it falls into the container. The sound emitted is converted into a digital signal, and then analyzed by signal-processing software that can identify the acoustic signature of the material disposed of with accuracy rates of more than 90%. The characterization is validated, and the user's account—accessible via a smartphone app** or smart card that communicates with the container—is credited with points if the waste disposed of matches what was expected. Points can be redeemed for special offers and discounts at participating businesses.

Cities that are using Cliiink have already seen their sorting rates rise significantly. Leti is currently investigating characterization technologies for waste other than glass.

*Startup Terradona began with just one person. It has grown to a 20-employee company serving 500,000 users. Currently, more than 130 recycling drop-off containers in the city of Grenoble, France have been equipped with the solution.

**The Cliiink app is available for Android and iOS.