In August 2018 Ethical Consumer found the following statement on the World of Books website www.worldofbooks.com:
"At World of Books we are committed to minimising our environmental impact. Each month we recycle over 4 million books, saving 22,000 tonnes of books a year from going into landfill. All of our paper waste is recycled within the UK and turned into corrugated cardboard.
"We strongly believe that it is a travesty to simply throw away a used book when there is nothing wrong with it. We believe in giving each book the chance of finding a new home."
The company was therefore considered to have a sustainable business model and therefore received a positive product sustainability mark.

Reference:

https://www.worldofbooks.com/ (2 August 2018)