On-site sorting of construction and demolition waste in Hong Kong

The construction industry is the major solid waste generator in Hong Kong. In 1998, it generated about 32710 t per day of construction and demolition (C&D) waste. In the management of such a huge quantity of C&D waste, Hong K ong has adopted a strategy of depositing the inert portion (e.g, sand, bric ks and concrete) of the waste at public filling areas for land reclamation and the non-inert portion (e.g. plastics, paper, wood) at municipal solid w aste landfills. However, the C&D waste arisen is usually in the form of a m ixture of both inert and non-inert materials. As a result, the waste has to be disposed of at landfills, aggravating the landfill shortage problem. Th ere is a paramount need to separate the C&D waste into its constituent part s before it is delivered to either the landfills or the public filling area s for disposal. In order to study the feasibility of carrying out on-site w aste sorting and the current situation of the building relating C&D waste g enerated in Hong Kong, a survey was conducted. This paper presents the resu lts of the survey undertaken to evaluate three alternative waste sorting me thods on building construction sites and to compare them with the use of an off-site central waste sorting facility. The results indicate source separ ation has the advantages of requiring less effort and resulting in better s egregation of inert and non-inert wastes as compared with waste sorting cen trally carried out at a designated area on- or off-site. In addition, the v iews of the building industry participants were also obtained through a que stionnaire survey to give a better understanding of their attitude on on-si te waste sorting. The results indicate that the building construction parti cipants are reluctant to carry out on-site waste sorting. Even when high a tipping fee is imposed, they have little incentive to perform on-site waste sorting which is considered to be time and labour demanding. Only through contractual requirements or legislation can on-site waste sorting be fully implemented and becomes a long-term solution to the landfill shortage probl em in Hong Kong. (C) 2001 Elsevier Science B.V. All rights reserved.