Cause of Impact
Construction waste include construction and demolition (C&D) materials, e.g. excavated C&D materials suitable for public fill, C&D waste such as cleared vegetation not suitable for public fill, chemical waste, and general refuse.
Mitigation measures are required to ensure the proper handling, storage, transportation and disposal of waste is carried out. Also measures to ensure that the generation of waste is avoided and minimised and that waste materials are recycled and treated as far as practicable. The recommended mitigation measures for all categories of waste are as follows:
- The requirements as stipulated in the ETWB TC(W) No.19/2005 Environmental Management on Construction Sites and the other relevant guidelines should be included in the Particular Specification for the Contractor as appropriate;
- The Contractor should be requested to submit an outline Waste Management Plan (WMP) prior to the commencement of construction work to provide an overall framework of waste management and reduction;
- The waste management hierarchy should be strictly followed in order to maximise the extent of waste reduction and cost reduction;
- A trip-ticket system should be established to monitor the disposal of public fill and solid wastes at public filling facilities and landfills, and to control fly-tipping; and
- A recording system for the amount of waste generated, recycled and disposed (locations) should be established.
The Project Proponent shall notify the CEDD of the estimated spoil volumes to be generated, and liaise and agree with the Public Fill Committee for the disposal of surplus inert C&D materials including good quality rock during detailed design of the project. The following mitigation measures should be implemented in handling the waste:
- Maintain temporary stockpiles and reuse excavated fill material;
- For the tunnel sections, stockpile excavated C&D material for immediate backfill once the tunnel section is completed;
- Carry out on-site sorting;
- Surplus artificial hard materials should be delivered to Tseung Kwan O Area 137 recycling plant or its successor for recycling;
- Make provisions in the Contract documents to allow and promote the use of recycled aggregates where appropriate;
- Implement a trip-ticket system for each works contract;
- Implement an enhanced WMP similar to ETWB TC(W) No. 19/2005 Environmental Management on Construction Sites to minimize their generation during the course of construction; and
- The Contractor should propose the final disposal sites for approval before implementation.
- Standard durable formwork or plastic facing for the construction works should be considered and used as far as practicable in order to minimise the arising of C&D materials;
- Use of wooden hoardings should also be avoided;
- Metal hoarding should be used to enhance the possibility of reuse and recycling;
- The purchasing of construction materials will be carefully planned in order to avoid the over ordering and wastage; and
- The Contractor should recycle as much of the C&D materials as possible on-site.
- The Contractor should register with EPD as chemical waste producer; and
- Chemical waste should be handled in accordance with the Code of Practice on the Packaging, Handling and Storage of Chemical Wastes.
- General refuse generated on-site should be stored in enclosed bins or compaction units separately from construction and chemical wastes. A reputable waste collector should be employed by the Contractor to remove general refuse from the site on a daily basis to minimize odour, pest and litter impacts. Burning of refuse on construction sites is prohibited by law;
- Aluminium cans are often recovered from the waste stream by individual collectors and separately labelled bins for collection should be provided if feasible; and
- Office wastes can be reduced through the recycling of paper if volumes are large enough to warrant collection.
The quantity and timing for the generation of waste during the construction phase have been estimated. The disposal quantities, methods and measures are devised in the construction methodology to minimise the surplus materials to be disposed off-site. Recommendations have been made for the Contractor for implementation during the construction period to minimise the waste generation and any off-site disposal. No construction work is allowed to proceed until all issues and arrangements on the management of C&D materials have been resolved and agreed between the responsible Government department and party.