8.1 This section identifies the types of solid wastes that are likely to be generated during the construction phase of the Project and evaluates the potential environmental impacts that may result from these wastes. The main solid waste would be construction and demolition (C&D) material generated from site clearance, soil nail installation, soil nail head construction, rock slope stabilization and raking drain installation. Mitigation measures and good site practices, including measures for waste handling, storage and disposal, are recommended with reference to the applicable waste legislation and guidelines.
Environmental Legislation and Standards
8.2 The criteria and guidelines for assessing waste management implications are set out in Annex 7 and Annex 15 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), respectively.
8.3 The following legislation relates to the handling, treatment and disposal of wastes in the Hong Kong SAR and has been used in assessing potential impacts:
· Waste Disposal Ordinance (Cap. 354)
· Waste Disposal (Chemical Waste) (General) Regulation (Cap. 354)
· Land (Miscellaneous Provisions) Ordinance (Cap. 28)
· Public Health and Municipal Services Ordinance (Cap. 132) - Public Cleansing and Prevention of Nuisances Regulation
Waste Management
8.4 The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes. Construction waste is defined as any substance, matter or thing that is generated from construction work and abandoned, whether or not it has been processed or stockpiled before being abandoned, but does not include any sludge, screenings or matter removed in or generated from any desludging, desilting or dredging works. Under the WDO, wastes can be disposed of only at designated waste disposal facilities.
8.5 Under the WDO, the Chemical Waste (General) Regulation 1992 provides regulations for chemical waste control, and administers the possession, storage, collection, transport and disposal of chemical wastes. The Environmental Protection Department (EPD) has also issued a ‘guideline’ document, the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), which details how the Contractor should comply with the regulations on chemical wastes.
8.6 The Public Cleansing and Prevention of Nuisances Regulation provides control on illegal tipping of wastes on unauthorised (unlicensed) sites.
Construction and Demolition (C&D) Materials
8.7 The current policy related to the disposal of C&D material is documented in the Works Branch Technical Circular No. 2/93, ‘Public Dumps’. Construction and demolition materials that are wholly inert, namely public fill, should not be disposed of to landfill, but taken to public filling areas, which usually form part of reclamation schemes. The Land (Miscellaneous Provisions) Ordinance requires that dumping licences be obtained by individuals or companies who deliver public fill to public filling areas. The Civil Engineering & Development Department (CEDD) issues the licences under delegated powers from the Director of Lands.
8.8 Under the Waste Disposal (Charges for Disposal of Construction Waste) Regulation, enacted in January 2006, construction waste delivered to a landfill for disposal must not contain more than 50% by weight of inert material. Construction waste delivered to a sorting facility for disposal must contain more than 50% by weight of inert material, and construction waste delivered to a public fill reception facility for disposal must consist entirely of inert material.
8.9 Measures have been introduced under Environment, Transport and Works Bureau (ETWB) TCW No. 33/2002, “Management of Construction and Demolition Material Including Rock” to enhance the management of construction and demolition material, and to minimize its generation at source. The enhancement measures include: (i) drawing up a Construction and Demolition Material Management Plan (C&DMMP) at the feasibility study or preliminary design stage to minimize C&D material generation and encourage proper management of such material; (ii) vetting of the C&DMMP prior to upgrading of the project to Category A in the Public Works Programme; and (iii) providing the contractor with information from the C&DMMP in order to facilitate him in the preparation of the Waste Management Plan (WMP) and to minimize C&D material generation during construction. Projects generating C&D material less than 50,000 m3 or importing fill material less than 50,000 m3 are exempt from the C&DMMP.
8.10 The criteria for assessing waste management implications are outlined in Annex 7 of the EIAO-TM. The methods for assessing potential waste management impacts during the construction phase follow those presented in Annex 15 of the EIAO-TM and include the following:
· Estimation of the types and quantities of the wastes to be generated.
· Assessment of potential impacts from the management of solid waste with respect to potential hazards, air and odour emissions, noise, wastewater discharge and transport.
· Assessment of impacts on the capacity of waste collection, transfer and disposal facilities.
Prediction and Evaluation of Environmental Impacts
8.11 The construction activities to be carried out for the proposed Project would generate a variety of wastes that can be divided into distinct categories based on their composition and ultimate method of disposal. The identified waste types include:
· Construction and demolition (C&D) material
· General refuse
· Chemical waste
8.12 Each type of waste arising is described below, together with an evaluation of the potential environmental impacts associated with generation, handling, storage and transport of the waste.
Construction and Demolition Materials
8.13 Construction and demolition (C&D) material would be generated from site clearance, soil nail installation, soil nail head construction, rock slope stabilization and raking drain installation. The estimated total volume of C&D material is approximately 995 m3. The C&D material would comprise approximately 93% soil. A breakdown of the volume of C&D material generated from the various works items is given in Table 8.1. Given the nature of the construction activities for the Project, it is anticipated that there would not be any opportunity for the reuse of C&D material on-site.
Table 8.1 Estimated Quantities of C&D Material
|
Construction works |
Soil, m3 |
Rock, m3 |
Total, m3 |
|
Site Clearance and Set up |
|||
|
Soil Nail Installation |
|||
|
Soil Nail Head Construction |
|||
|
Raking Drain Installation |
|||
|
Scaling |
|||
|
Rock bolts / dowels |
|||
|
Landscape Works |
|||
|
|
8.14 The C&D material would require disposal at the designated public fill reception facility, as agreed with the Secretary of the Public Fill Committee, for other beneficial uses. Provided that a trip-ticket system is established for the disposal of the C&D material, as recommended in Section 8.24, and that good site practices are adhered to, adverse environmental impacts and nuisance would not be expected.
Chemical Waste
8.15 The maintenance and servicing of construction plant and equipment may generate some chemical wastes such as cleaning fluids, solvents, lubrication oil and fuel. It is difficult to quantify the amount of chemical waste that will arise from the construction activities since it will be dependent on the Contractor’s on-site maintenance requirements and the amount of plant utilised. However, it is anticipated that the quantity of chemical waste, such as lubricating oil and solvent produced from plant maintenance, would be small and in the order of a few cubic metres per month. The amount of chemical waste to be generated will be quantified in the site Waste Management Plan to be prepared by the Contractor.
8.16 Chemical wastes arising during the construction phase may pose environmental, health and safety hazards if not stored and disposed of in an appropriate manner as stipulated in the Waste Disposal (Chemical Waste) (General) Regulations. The potential hazards include:
· Toxic effects to workers
· Adverse impacts on water quality from spills
· Fire hazards
8.17 Materials classified as chemical wastes will require special handling and storage arrangements before removal for appropriate treatment at the Chemical Waste Treatment Facility (CWTF) or other licensed facility. Wherever possible opportunities should be taken to reuse and recycle materials. Mitigation and control requirements for chemical wastes are detailed in Section 8.23. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts would not be expected to result.
General Refuse
8.18 The construction workforce would generate general refuse comprising food scraps, waste paper, empty containers, etc. Such refuse should be properly managed so intentional or accidental release to the surrounding environment does not occur. Disposal of refuse at sites other than approved waste transfer or disposal facilities shall be prohibited. Effective collection of site wastes would be required to prevent waste materials being blown around by wind or creating an odour nuisance or pest and vermin problem. Waste storage areas should be well maintained and cleaned regularly. With the implementation of good waste management practices at the site, adverse environmental impacts would not be expected from the storage, handling and transportation of workforce wastes.
Good Site Practices
8.19 Adverse impacts related to waste management are not expected to 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 waste 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.
· Regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors.
Waste Reduction Measures
8.20 Good management and control can prevent the generation of a 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.
· Encourage collection of aluminium cans, PET bottles and paper by providing separate labelled bins to enable these wastes to be segregated from other general refuse generated by the work force.
· Any unused chemicals or those with remaining functional capacity shall be recycled.
· Proper storage and site practices to minimise the potential for damage or contamination of construction materials.
· Plan and stock construction materials carefully to minimise amount of waste generated and avoid unnecessary generation of waste.
8.21 In addition to the above measures, specific mitigation measures are recommended below for the identified waste arisings to minimise environmental impacts during handling, transportation and disposal of these wastes.
General Refuse
8.22 General refuse should be stored in enclosed bins or compaction units separate from C&D material. A licensed waste collector should be employed by the contractor to remove general refuse from the site, separately from C&D material. Preferably an enclosed and covered area should be provided to reduce the occurrence of 'wind blown' light material.
Chemical Wastes
8.23 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 collected by a licensed collector for disposal at the CWTF or other licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.
Construction and Demolition Material
8.24 In order to monitor the disposal of public fill at public fill reception facilities and to control fly tipping, a trip-ticket system should be established in accordance with ETWB TCW No. 31/2004.
Evaluation of Residual Impacts
8.25 With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste arisings, no residual impact is expected to arise during the construction of the proposed Project.
8.26 Waste management will be the contractor’s responsibility to ensure that all wastes produced during the construction of the Project are handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements. The recommended mitigation measures should form the basis of the site Waste Management Plan to be developed by the Contractor in the construction stage and deposit with EPD.
8.27 It is recommended that the waste arisings generated during the construction activities be audited periodically to determine if wastes are being managed in accordance with approved procedures and the site Waste Management Plan. In addition, the routine site inspections should check the implementation of the recommended good site practices and other waste management mitigation measures.
8.28 Wastes generated by the construction activities are likely to include C&D material, general refuse from the workforce and chemical waste from the maintenance of construction plant and equipment. Provided that these identified waste arisings are handled, transported and disposed of using approved methods and that the recommended good site practices are strictly followed, adverse environmental impacts would not be expected during the construction phase.