Minimizing demolition wastes in Hong Kong public housing projects

Being one of the major housing developers in Hong Kong, the Hong Kong Housing Authority (HA) carries out a large number of construction and demolition projects. As a result, a large amount of construction and demolition waste is produced. As for demolition projects, demolition wastes usually contain a large amount of reusable materials. If sorted out properly, these materials could be better reused or recycled. Two case studies have been carried out on public housing projects to quantify the recovery rates of various types of demolition wastes in demolition projects and to assess the implementation of on-site sorting requirements. The current practices of demolition contractors in Hong Kong mainly focus on the working procedures and waste generation during the main demolition stage and sorting of waste is difficult due to cross contamination although on-site sorting has been stated as a requirement in the contract. The demolition method statement should include working details of both the salvaging and the demolition stages to affect waste sorting and recycling. Selective demolition should be considered to further improve the waste recycling rate but there is a need to develop recycling markets to provide outlets for the collected recyclables.