From sea to plate … to sea? Hong Kong puts oyster shells to a new use

Discarded shells from restaurants and hotels are being used to restore damaged oyster ecosystems, promote biodiversity and lower pollution in the city's bays

Every Thursday around noon, a brown minivan pulls up in the alley behind the glitzy Peninsula hotel at Victoria Harbour in Kowloon, Hong Kong. A porter rushes out to meet it from the back door of the hotel kitchen, lugging a large white rice sack. The driver weighs the bag on a handheld scale - it's 40kg (88lb) - then chucks it into the back of the vehicle with a surprising clank.

The van takes the sack to a recycling facility just outside the city, and tips out the contents: not rice, but hundreds of oyster shells. They will lie in the sun for a year to ensure any rotting flesh and bacteria are destroyed, before being reintroduced into Hong Kong's bays as part of a series of restored oyster reefs.