5                    SOLID WASTE MANAGEMENT

5.1              Introduction

5.1.1          Waste management will be the contractor’s responsibility to ensure that all wastes produced during the construction of the WDII are handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements.  The contractor will be required to ensure that loss of dredged material does not take place during transportation of the material in barges to the designated marine disposal ground.

5.1.2          Other waste materials generated during construction activities, such as construction and demolition (C&D) materials, chemical wastes and general refuse from the workforce, are recommended to be audited at regular intervals (at least monthly) to ensure that proper storage, transportation and disposal practices are being implemented.  This monitoring of waste management practices will ensure that these solid and liquid wastes generated during construction are not disposed of into the surrounding marine waters.  The Contractor will be responsible for the implementation of any mitigation measures to minimise waste or redress problems arising from the waste materials.

5.2              Waste Control and Mitigation Measures

5.2.1          Mitigation measures for waste management are summarised below. With the appropriate handling, storage and removal of waste arisings during the construction of the WDII as defined below, the potential to cause adverse environmental impacts will be minimised.

Marine Sediments

5.2.2          The basic requirements and procedures for dredged mud disposal are specified under the WBTC No. 3/2000.  The management of the dredging, use and disposal of marine mud is monitored by the MFC, while the licensing of marine dumping is the responsibility of the Director of Environmental Protection (DEP).

5.2.3          The dredged marine sediments will be loaded onto barges and transported to designated disposal sites depending on their level of contaminants.  As discussed in EIA Report, the majority of the marine sediment to be dredged is Category H (biological test not required).  In accordance with the WBTC No. 3/2000, the contaminated material must be dredged and transported with great care, and the mitigation measures recommended in Sections 4.9.7 and 5.2.5 of this Manual should be strictly followed.  Furthermore, the dredged contaminated sediment must be effectively isolated from the environment upon final disposal and shall be disposed of at the East Sha Chau Contaminated Mud Pits that is designated for the disposal of contaminated mud in Hong Kong.

5.2.4          At this stage, based on the existing vibrocore sampling results, it is estimated that some 2,100 m3 of PCB-contaminated sediments may require pre-treatment or special disposal arrangements.  Pre-treatment by techniques such as bioremediation, dechlorination, soil washing, solvent extraction and thermal desorption have been examined.  Treatability studies would be needed to confirm the suitability of the pre-treatment process and material sizing and dewatering may also be required.  An off-site treatment facility would need to be established.  For these reasons, especially in view of the relatively small amount of contaminated sediments involved, and given the possible consequential implementation implications for the project, pre-treatment is not considered suitable for the WDII project.  It has therefore been agreed with EPD that special disposal arrangements, rather than pre-treatment, would be appropriate provided there would be negligible loss of sediment to the marine environment during the dumping operations.

5.2.5          During transportation and disposal of the dredged marine sediments, the following measures should be taken to minimise potential impacts on water quality:

·         Bottom opening of barges shall be fitted with tight fitting seals to prevent leakage of material.  Excess material shall be cleaned from the decks and exposed fittings of barges and hopper dredgers before the vessel is moved.

·         Monitoring of the barge loading shall be conducted to ensure that loss of material does not take place during transportation.  Transport barges or vessels shall be equipped with automatic self-monitoring devices as specified by the Director of Environmental Protection.

Good Site Practices and Waste Reduction Measures

5.2.6          It is not anticipated that adverse waste management related impacts would arise, provided that good site practices are strictly followed.  Recommendations for good site practices during the construction activities include:

·         nomination of an approved person, such as a site manager, to be responsible for good site practices, arrangements for collection and effective disposal to an appropriate facility, of all wastes generated at the site;

·         training of site personnel in proper waste management and chemical handling procedures;

·         provision of sufficient waste disposal points and regular collection for disposal;

·         appropriate measures to minimise windblown litter and dust during transportation of waste by either covering trucks or by transporting wastes in enclosed containers;

·         separation of chemical wastes for special handling and appropriate treatment at the Chemical Waste Treatment Facility (CWTF);

·         regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors; and

·         a recording system for the amount of wastes generated, recycled and disposed of (including the disposal sites).

5.2.7          In order to monitor the disposal of C&D waste at landfills and to control fly tipping, a trip-ticket system should be included as one of the contractual requirements and implemented by an Environmental Team undertaking the Environmental Monitoring and Audit work.  An IC(E) should be responsible for auditing the results of the system.

5.2.8          Good management and control can prevent the generation of significant amount of waste.  Waste reduction is best achieved at the planning and design stage, as well as by ensuring the implementation of good site practices.  Recommendations to achieve waste reduction include: 

·          segregation and storage of different types of waste in different containers, skips or stockpiles to enhance reuse or recycling of materials and their proper disposal;

·          to encourage collection of aluminium cans by individual collectors, separate labelled bins shall be provided to segregate this waste from other general refuse generated by the work force;

·          any unused chemicals or those with remaining functional capacity shall be recycled;

·          use of reusable non-timber formwork, such as in casting the tunnel box sections, to reduce the amount of C&D material;

·          prior to disposal of C&D waste, it is recommended that wood, steel and other metals shall be separated for re-use and / or recycling to minimise the quantity of waste to be disposed of to landfill;

·          proper storage and site practices to minimise the potential for damage or contamination of construction materials; and

·          plan and stock construction materials carefully to minimise amount of waste generated and avoid unnecessary generation of waste.

5.2.9          In addition to the above good site practices and waste reduction measures, specific mitigation measures are recommended below for the identified waste arisings to minimise environmental impacts during handling, transportation and disposal of these wastes.  The transportation of these wastes by barge to the disposal location is recommended, as far as practicable, in order to reduce potential noise and air quality impacts from road transportation.

Construction Waste and General Refuse

5.2.10      A collection area should be provided where wastes can be stored and loaded prior to removal from site.  An enclosed and covered area is preferred to reduce the occurrence of 'wind blow' light material.  If an open area is unavoidable for the storage or loading / unloading of wastes, then the area should be bunded and all the polluted surface run-off collected within this area should be diverted into sewers.

Chemical Wastes

5.2.11      After use, chemical wastes (for example, cleaning fluids, solvents, lubrication oil and fuel) should be handled according to the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes.  Spent chemicals should be stored and collected by an approved operator for disposal at the CWTF or other licensed facility in accordance with the Chemical Waste (General) Regulation.

5.2.12      Any service shop and minor maintenance facilities should be located on hard standings within a bunded area, and sumps and oil interceptors should be provided.  Maintenance of vehicles and equipment involving activities with potential for leakages and spillage shall only be undertaken within areas appropriately equipped to control these discharges.

Construction and Demolition Material

5.2.13      The C&D material should be sorted on-site into inert C&D material (that is, public fill) and C&D waste.  Considering that a large quantity of C&D material will be generated from the excavation and demolition works and in order to minimise the impact resulting from collection and transportation of material for off-site disposal, it is recommended that the inert C&D material should be re-used on-site in the reclamation works.  Inert C&D material should be broken down to 250 mm in size for reuse as public fill in the WDII reclamation.  C&D waste, such as wood, glass, plastic, steel and other metals should be reused or recycled and, as a last resort, disposed of to landfill.  It is recommended that a suitable area shall be designated to facilitate the sorting process and a temporary stockpiling area will be required for the separated materials. Bentonite slurries used in diaphragm wall and bore-pile construction should be reconditioned and reused wherever practicable.  The disposal of residual used bentonite slurry should follow the good practice guidelines stated in ProPECC PN 1/94 “Construction Site Drainage” and listed as follows:

·         If the disposal of a certain residual quantity cannot be avoided, the used slurry may be disposed of at the marine spoil grounds subject to obtaining a marine dumping licence from EPD on a case-by-case basis.

·         If the used bentonite slurry is intended to be disposed of through the public drainage system, it should be treated to the respective effluent standards applicable to foul sewers, storm drains or the receiving waters as set out in the Technical Memorandum on Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters (TM-DSS).

5.2.14      Table 5.1 provides a summary of the various waste types likely to be generated during the reclamation works, together with the recommended handling and disposal methods.  The implementation schedule of the recommended mitigation measures is presented in Appendix A.

Table 5.1  Summary of Waste Handling Procedures and Disposal Routes 

Waste Type



Construction and Demolition Material (include excavated material)

Sort on-site into :

·         Inert C&D material (public fill)



·         C&D waste


·         Segregate inert fill material to avoid contamination from other waste arisings


Reuse on-site for reclamation provided material broken up to 250 mm in size (approx. 44,000m3)

Off-site disposal to landfill (approx. 5,800 m3)

Reuse on-site as far as practicable (approx. 400,000 m3)

Surplus fill material to be disposed off-site (approx. 170,000 m3)

Surplus rock fill arising from the temporary breakwater to be disposed off-site (approx. 100,000 m3)


Dredged Sediments*

Contaminated:  techniques to minimise resuspension (closed grabs, tight seal on barges controlled loading and transfer)


MFC contaminated mud pit

(approx. 600,000 m3)



Uncontaminated:  minimise resuspension (closed grabs, tight seal on barges, controlled loading and transfer)


MFC gazetted marine disposal ground

(approx. 420,000 m3)


Chemical Wastes

Recycle on-site or by licensed companies

Stored on-site within suitably designed containers


Chemical Waste Treatment Facility

General Refuse

Provide on-site refuse collection facilities

Refuse station for compaction and containerisation and then to landfill


*      Details of handling procedures and disposal methods for dredged sediment should refer to Sections 4.9.7 and 5.2.5.  The need for special disposal procedures for dredged contaminated sediments from the Causeway Bay Typhoon Shelter will be examined in detail at the design stage of the Project, as necessary, based on the sediment testing results of the further ground investigation works.