5.1.1 Waste management would be the contractor’s responsibility to ensure that all wastes produced during the construction works for the Project are handled, stored and disposed of in accordance with good waste management practices, EPD’s regulations and requirements.
5.1.2 Waste materials generated during construction activities, such as construction and demolition (C&D) materials and general refuse, are recommended to be audited at regular intervals (at least quarterly) to ensure that proper storage, transportation and disposal practices are being implemented. This monitoring of waste management practices would ensure that these solid wastes generated during construction are not disposed into the nearby coastal waters. The Contractor would be responsible for the implementation of any mitigation measures to minimise waste or redress problems arising from the waste materials. A waste management plan (WMP) should be prepared in accordance with ETWB TCW No. 19/2005 and submitted to the Engineer for approval. The monitoring and auditing requirements of the WMP as detailed in ETWB TCW No. 19/2005 should be followed with regard to the management of C&D material.
5.2.1 Mitigation measures for waste management are summarised below. With the appropriate handling, storage and removal of waste arisings during the construction works as defined below, the potential to cause adverse environmental impacts would be minimised. During the site inspections, the ET shall pay special attention to the issues relating to waste management and check whether the Contractor has implemented the recommended good site practices and other mitigation measures.
Good Site Practices
5.2.2 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 handling procedures;
· Provision of sufficient waste disposal points and regular collection of waste;
· Appropriate measures to minimise windblown litter and dust during transportation of waste by either covering trucks or by transporting wastes in enclosed containers; and
· Regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors.
Waste Reduction Measures
5.2.3 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:
· Use of steel formwork instead of timber formwork to reduce the generation of timber waste;
· 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 by individual collectors by providing separate labelled bins to enable this waste to be segregated from other general refuse generated by the work force;
· 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.
5.2.4 In addition to the above measures, specific mitigation measures are recommended below for the identified waste arising to minimise environmental impacts during handling, transportation and disposal of these wastes.
Construction and Demolition Material
5.2.5 In order to minimise the impact resulting from collection and transportation of C&D material for off-site disposal, the C&D material from the excavation works for road formation and engineering infrastructure should be reused on-site as backfilling material as far as practicable. In addition, granitic rock generated from tunnel blasting works should be exported for recycling for aggregate as far as practicable.
Marine Sediments
5.2.6 Sediment encountered would be reused as filling material on-site after cement stabilization. The reuse of cement stabilized sediment and adoption of RBRGs to assess stabilized sediment have been proposed in the current C&DMMP. Marine Fill Committe has no adverse comment on the current C&DMMP. It should be noted that stabilized sediment will be reuse in project only and will not dispose in public fill. Some 17,450 m3 of sediment is considered be suitable for reuse as filling material. Remaining 1,910m3 of sediment exceeded the RBRG for lead. The treated material from these sediments has to comply with UTS and UCS before reusing as filling material.
5.2.7 A treatment area should be confined for carrying out the cement stabilization mixing and temporary stockpile. The area should be designed to prevent leachate from entering the ground. Leachate, if any, should be collected and discharged adequately.
5.2.8 In case cement stabilization is not a practical treatment for the sediment, the sediment may be disposed according to ETWB TC(W) No. 34/2002. The basic requirements and procedures for sediment disposal are specified under the ETWB TCW No. 34/2002. 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).
5.2.9 The marine sediments would be loaded onto barges and transported to the designated disposal site. Based on the review of the sediment testing results, it was estimated that some 19,360 m3 of sediments would be suitable for Type 1, Type 2 and Type 3 disposal.
5.2.10 During transportation and disposal of the marine sediments, the following measures should be taken to minimise potential impacts on water and air quality:
· Stockpiling of contaminated sediments should be avoided as far as possible. If temporary stockpiling of contaminated sediments is necessary, the sediment should be covered by tarpaulin and the area should be placed within earth bunds or sand bags to prevent leachate from entering the ground, nearby drains and surrounding water bodies. The stockpiling areas should be completely paved or covered by linings in order to avoid contamination to underlying soil or groundwater. Separate and clearly defined areas should be provided for stockpiling of contaminated and uncontaminated materials. Leachate, if any, should be collected and discharged adequately.
· The sediment should be kept wet and probably covered to prevent odour/dust emission when placed on barge.
· Bottom opening of barges should be fitted with tight fitting seals to prevent leakage of material. Excess material should be cleaned from the decks and exposed fittings of barges and hopper dredgers before the vessel is moved.
· Barges or hopper barges should not be filled to a level that would cause the overflow of materials or sediment-laden water during loading or transportation.
· Monitoring of the barge loading should be conducted to ensure that loss of material does not take place during transportation.
· Transport barges or vessels should be equipped with automatic self-monitoring devices as specified by the DEP.
Chemical Wastes
5.2.11 If chemical wastes are produced at the construction site, the Contractor would be required to register with the EPD as a Chemical Waste Producer and to follow the guidelines stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes. Good quality containers compatible with the chemical wastes should be used, and incompatible chemicals should be stored separately. Appropriate labels should be securely attached on each chemical waste container indicating the corresponding chemical characteristics of the chemical waste, such as explosive, flammable, oxidizing, irritant, toxic, harmful, corrosive, etc. The Contractor shall use a licensed collector to transport and dispose of the chemical wastes, to either the Chemical Waste Treatment Centre at Tsing Yi, or other licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.
General Refuse
5.2.12 General refuse should be stored in enclosed bins or compaction units separate from C&D material. A reputable 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 'windblown' light material.
5.2.13 The implementation schedule for the recommended waste management mitigation measures is presented in Appendix C.