8. WASTE MANAGEMENT IMPLICATIONS

8.1 Introduction

8.1.1 This section identifies potential wastes that may arise from the Project, and assesses potential environmental impacts associated with their handling and disposal. Options of reuse, minimization, recycling, treatment, storage, collection, transport and disposal of such wastes are examined. Where appropriate, procedures for waste reduction and management have been considered, with environmental control measures to avoid or minimize impacts recommended.

8.2 Environmental Legislation, Policies, Plans, Standards and Criteria

8.2.1 The following legislation covers, or relates to the handling, treatment and disposal of waste in Hong Kong:
· Environmental Impact Assessment Ordinance (Cap 499)
· 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
· Dumping at Sea Ordinance (Cap 466)

8.2.2 The following documents, guidelines and circulars also relate to waste management in Hong Kong:
· Technical Memorandum on Environmental Impact Assessment Process, Annex 15 - Guidelines for Assessment of Waste Management Implications, and Annex 7 - Criteria for Evaluating Waste Management Implications
· Hong Kong Planning Standards and Guidelines (HKPSG), Chapter 9 - Environment
· New Disposal Arrangements for Construction Waste, EPD & Civil Engineering Department (1992)
· Code of Practice on the Packaging, Labeling and Storage of Chemical Wastes, EPD (1992)
· WBTC No. 2/93, Public Dumps
· WBTC No. 2/93B, Public Filling Facilities
· Practice Note for Professional Persons - Construction Site Drainage (ProPECC PN 1/94), Professional Persons Consultative Committee (1994)
· WBTC No. 16/96, Wet Soil in Public Dumps
· Waste Reduction Framework Plan, 1998 - 2007, Planning Environment and Lands Branch, Government Secretariat (5 November 1998)
· WBTC No. 4/98, Use of Public Fill in Reclamation and Earth Filling Projects
· WBTC No. 4/98A, Use of Public Fill in Reclamation and Earth Filling Projects
· WBTC No. 5/98, On Site Sorting of Construction Waste on Demolition Sites
· WBTC No. 5/99, Trip-ticket System for Disposal of Construction and Demolition Material (will be replaced by WBTC No. 21/2002 in September 2002)
· WBTC No. 5/99A, Trip-ticket System for Disposal of Construction and Demolition Material (will be replaced by WBTC No. 21/2002 in September 2002)
· WBTC No. 19/99, Metallic Site Hoardings and Signboards
· WBTC No. 25/99, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers
· WBTC No. 25/99A, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers (Amendment 1)
· WBTC No. 25/99C, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers
· WBTC No. 3/2000, Management of Dredged/Excavated Sediment
· WBTC No. 12/2000, Fill Management
· WBTC No. 29/2000, Waste Management Plan
· WBTC No. 12/2002, Specifications Facilitating the Use of Recycled Aggregates
· ETWBTC (W) No. 33/2002 Management of construction and demolition material including rock

8.3 Assessment Methodology

8.3.1 The method for assessing potential waste management impacts during construction adheres to that prescribed in Annexes 7 and 15 of the Technical Memorandum on Environmental Impact Assessment Process. This method is summarized as follows:
· Estimation of the types and quantities of waste generated.
· Assessment of potential impacts from the management of solid waste with respect to potential hazards, air and odour emissions, noise, wastewater discharges and transport.
· Assessment of potential impacts on the capacity of waste collection, transfer and disposal facilities.

8.3.2 This assessment covers the analysis of construction activities and waste generation as well as practicable measures for waste management.

8.4 Baseline Conditions

Existing Sediment Quality

8.4.1 EPD has been regularly conducting sediment sampling at four stations (DS1, DS2, DS3 and DS4) in the Deep Bay Water Control Zone (Deep Bay WCZ). The sampling locations are shown in Figure 7.8 under Chapter 7.

8.4.2 DS1 is located close to the outlet of Shenzhen River. Based on the sediment quality data collected by EPD from 1995 to 2000, the average zinc levels at DS1 were high (86 mg/kg - 360 mg/kg). The recorded zinc levels at DS1 in 1997, 1998 and 2000 exceeded the UCEL of 270 mg/kg as specified in WBTC No. 3/2000. The nickel levels in the sediment collected at DS1 were also high between 1997 and 1998, but subsequently decreased in 1999. Nickel levels increased again in 2000. The highest nickel level as recorded in August 1998 was above the UCEL of 40 mg/kg. The 6-year records indicated that the cadmium levels at DS1 were low (0.1 - 0.5 mg/kg) and were much below the LCEL of 1.5 mg/kg. High concentrations of copper (84 - 98 mg/kg) and arsenic (14 - 20 mg/kg) were also recorded in 1997, 1998 and 2000. These levels respectively exceeded the LCEL for copper (65 mg/kg) and arsenic (12 mg/kg), but were below their corresponding UCEL (110 mg/kg for copper and 42 mg/kg for arsenic). The copper and arsenic levels in the sediment decreased in 1999 but increased again in 2000 with the values of 98 mg/kg and 20 mg/kg, respectively. Two readings of lead level (77 and 87 mg/kg) exceeded the LCEL (75 mg/kg) at DS1 in January 1997 and January 2000. No exceedances of the LCEL for chromium and mercury were found at this station. There were no records for silver from 1995 to 1997. The recorded silver levels at DS1 between 1998 and 2000 were at the LCEL of 1 mg/kg.

8.4.3 Regarding organic micro-pollutants, PCB levels (5 - 24 mg/kg) at DS1 from 1995 to 1999 were all below the LCEL of 23 mg/kg, but a reading in 2000 (24 mg/kg) exceeded the LCEL. PAH levels were 46 - 523 mg/kg. The PAH levels at DS1 were below LCEL. There was no measurement of TBT. The sediment at DS1 ranged between Category L material and Category H material from 1995 to 2000.

8.4.4 DS2 is located closest to the proposed SWC alignment option. One reading of zinc level in January 1997 (220 mg/kg) exceeded the LCEL of 200 mg/kg. The rest of the data measured between 1995 and 2000 were below the LCEL for zinc, with a range between 69 and 190 mg/kg. A number of exceedances of the LCEL for arsenic were recorded at DS2. Except for the copper level (66 mg/kg) recorded in January 1997, most of the copper levels recorded were lower than the LCEL of 65 mg/kg. The levels of cadmium (0.1 - 0.4 mg/kg), chromium (21 - 47 mg/kg), nickel (11 - 28 mg/kg), lead (33 - 69 mg/kg) and mercury (0.05 - 0.2 mg/kg) recorded from 1995 - 2000 were below their corresponding LCEL. The silver levels recorded in 1998 and 2000 were at the LCEL of 1 mg/kg. The PAH levels (39 - 423 ug/kg) and PCB levels (5 - 20 ug/kg) were relatively low at DS2. Comparing the available EPD data with the classification criteria of WBTC No. 3/2000, the sediment at DS2 was mainly Category M material.

8.4.5 DS3 is located in the Outer Deep Bay. Parameters with concentrations below the respective LCELs include zinc (69 - 150 mg/kg), nickel (14 - 32 mg/kg), lead (30 - 60 mg/kg), mercury (0.05 - 0.18 mg/kg), copper (19 - 53 mg/kg), chromium (23 - 48 mg/kg) and cadmium (0.1 - 0.3 mg/kg). High arsenic levels were however recorded at this station, with values ranging from 12 to 20 mg/kg. The silver levels recorded in 1998 and 2000 were at the LCEL of 1 mg/kg. The PAH levels and PCB levels measured at this station were 40 - 118 ug/kg and 5 - 10 ug/kg, respectively. The 6-year records indicated that the sediment at DS3 might classify as Category M material.

8.4.6 DS4 is located near the mouth of Deep Bay and is relatively distant from the Shenzhen River discharge. In general, the sediment contaminant levels at this station were low compared to those at the other stations. Parameters with concentrations below the respective LCELs include zinc (36 - 140 mg/kg), nickel (7 - 24 mg/kg), lead (18 - 68 mg/kg), mercury (0.05 - 0.15 mg/kg), copper (6 - 45 mg/kg), chromium (14 - 44 mg/kg) and cadmium (0.1 - 0.2 mg/kg). Most of the arsenic levels (10 - 19 mg/kg) were higher than the LCEL of 12 mg/kg. The silver levels records in 1998 and 2000 were at the LCEL of 1 mg/kg. The PAH levels and PCB levels measured at DS4 were 39 - 96 ug/kg and 5 - 40 ug/kg, respectively. Comparing the available EPD data with the classification criteria of WBTC No. 3/2000, the sediment at DS4 was mainly Category M material.

8.5 Identification of Potential Sources of Waste

8.5.1 Construction activities of the Project are expected to generate a variety of wastes which may include:
· Marine Dredged Sediments
· Excavated Materials;
· Construction and Demolition (C&D) Material;
· Chemical Waste; and
· General Refuse.

8.5.2 If not properly managed, the handling and disposal of these wastes may cause environmental impacts and nuisance.

8.5.3 The operational phase of the Project, on the other hand, is not expected to generate any quantities of waste. As no operator would be required for the SWC, general refuse from operations is not likely to be an issue.

Marine Dredged Sediments

8.5.4 Vibrocore and grab sediment samples were collected during site investigation (SI) for analysis of sediment quality. Figures 8.1 and 8.2 show the distribution of sediment sampling points within the boundary of Hong Kong. Categories L, M and H materials may be generated from the dredging operations. Particular attention will need to be paid to the disposal of these materials.

8.5.5 The proposed enhancement measure of dredging sediment at Mai Po to restore the functions of Gei Wais would generate dredged material, which needs to be disposed of at designated sites. Disposal of the dredged material should be in compliance with the Dumping at Sea Ordinance.

Excavated Materials

8.5.6 Excavation of soil and rock material on land would be minimal for the SWC project since all the permanent works for the SWC project would be located offshore and the land issues would be covered under the DBL project.

Construction and Demolition Material

8.5.7 Construction and demolition material arises from C&D activities such as site clearance and demolition works. C&DM may include the following:
· inert portion of C&D material such as rock, concrete, etc.;
· non-inert portion such as timber, etc.

8.5.8 The Contractor is responsible for sorting C&DM into inert and non-inert portions. Inert portion of C&DM is fill material and hence, should be reused on site as far as possible. Surplus inert C&DM may be disposed of at public filling areas depending on the percentage of inert content. Non-inert portion of C&DM should be reused whichever possible and be disposed of at landfills as the last resort.

Chemical Waste

8.5.9 The Waste Disposal (Chemical Waste) (General) Regulation defines chemical waste as any substance being scrap material or unwanted substances specified in its Schedule 1, and provides a complete list of such substances. However, substances likely to be generated by construction activities would mainly arise from the maintenance of equipment. These may include the following items:
· Scrap batteries or spent acid/alkali
· Used engine oils, hydraulic fluids and waste fuel
· Spent mineral oils/cleaning fluids from mechanical machinery
· Spent solvents/solutions, some of which may be halogenated, from equipment cleaning activities

General Refuse

8.5.10 The Project would generate general refuse including paper and food waste. The amount that may be produced is dependent on the size of the workforce at site. If proper measures are not implemented, the storage of general refuse has the potential to give rise to environmental impacts.

8.6 Prediction and Evaluation of Environmental Impacts

8.6.1 The amount of wastes arising from construction and the potential environmental impacts associated with their handling, storage, transport and disposal are discussed below:

Marine Dredged Sediments

8.6.2 The dredging operations, and the handling and disposal of these wastes may cause impacts to the marine environment and its ecology if proper management measures are not implemented. The dispersion of suspended solids and the release of contaminants from the sediment into the water column can lead to significant consequences, including effects to marine organisms and the food chain. Quantitative assessment of potential impacts relating to sediment and water quality is documented in Section 7 of this Report. The estimated total volume of sediment to be dredged is about 57,000 m3. The sediment volumes for open sea disposal and confined marine disposal would be approximately 34,500 m3 and 22,500 m3 respectively.

8.6.3 Sediment dredging would be carried out in the inlet channel and proposed access route at Mai Po for the enhancement measure. With reference to EPD's data at DS1 and AFCD's report , the sediment near Mai Po may have a certain level of contamination. Details are presented in Section 7. Based on the laboratory results, the sediment volumes for Category M material and Category H material (<10xLCEL) were the same (~4,400 m3). Assuming that the Category M materials could not pass the biological test, the estimated total volume of sediment for confined marine disposal was approximately 8,800 m3. At the detailed design stage, a detailed investigation of the sediment quality would be carried out for preparation of a Sediment Quality Report. Further approval from EPD and MFC is required for disposal of the sediment at designated sites.

8.6.4 The lengths of inlet channel and the proposed access route are about 1.4 km and 0.8km respectively. The width of dredging along the inlet channel and the access route is about 4m and the depth of sediment to be dredged is about 1.0m. An estimate of the dredged material is approximately 8,800 m3. The outlet of the dredged material is to be at confined marine disposal sites, i.e. East Sha Chau mud pits.

Excavated Materials

8.6.5 The SWC is connected to DBL at Ngau Hom Shek. All the permanent works for the SWC project would be located offshore. Excavation of soil and rock material on land would be minimal for the SWC project. All land issues would be covered in the DBL project.

Construction and Demolition Material

8.6.6 C&DM from site clearance and demolition works has been estimated based on the amounts of hard paved slab, temporary structures and small houses of about 1 storey high which are likely to be demolished or cleared. It is estimated that up to 0.1 ha worth of hard paved area will be cleared. Assuming 0.1 m thick of hard paved slab, 100 m3 of material would be generated. Around the SWC area, there are about 15 temporary structures and small houses, which will require demolition. Based on the assumption that 40 m3 of C&DM would be produced by the demolition of temporary structures and small houses respectively, 600 m3 of C&DM would be generated. In total, approximately 700 m3 C&DM would be generated.

8.6.7 It is considered that the handling and disposal of such C&DM would unlikely be a key issue and the potential environmental impact arising from handling and disposal of such waste would be negligible. However, improper disposal of C&D material would cause environmental impacts. Depending on the disposal location, marine environment and its ecological system may be affected.

8.6.8 The volume of C&DM that may be re-used or recycled is estimated to be about 20% of the total volume of 700 m3.

Chemical Waste

8.6.9 Chemical waste may pose serious environmental, health and safety hazards if it is not properly managed. These hazards include:

· Toxic effects to workers
· Adverse effects on water quality from spills
· Fire hazards
· Disruption of sewage treatment works should the chemical waste enter the sewerage system

8.6.10 The amount of chemical waste arising from the construction activities would be dependent on the contractor's on-site maintenance practices and the amount of plant and number of vehicles deployed. It is anticipated that the quantity of chemical waste, such as lubricating oil and solvent, produced from plant maintenance would be relatively small. Such waste should be collected by licensed chemical waste collectors for subsequent disposal at licensed waste disposal facilities, such as the Chemical Waste Treatment Centre in Tsing Yi.

General Refuse

8.6.11 The number of workers at the site is estimated to be about 300. The quantity of general refuse generated by each person would be 0.55 kg/day (EPD, 1999), thus about 0.165 tonnes of waste would be generated. During a projected construction period of 2.5 years, the total volume of C&I waste generated by the workforce would therefore be about 151 tonnes.

8.6.12 Potential environmental impacts of general refuse include odour (if waste is not collected frequently), windblown litter, water quality impacts (if waste enters water bodies), and visual impacts. The refuse may also attract pests and vermin if the storage areas are not well maintained and cleaned regularly. In addition, disposal of waste at sites other than approved waste transfer or disposal facilities can also lead to environmental impacts.

8.6.13 Handling and disposal of general refuse should cope with the presence of peak workforce during the construction period. Provided that the refuse is stored and transported in accordance with proper practices and disposed at licensed landfills, the potential environmental impacts would be minimal.

8.7 Mitigation Measures

8.7.1 This section sets out measures that should be taken to avoid or minimize potential adverse impacts from construction waste of the Project. The main contractors should act as the overall coordinator for the management of waste and follow the requirements of the Waste Management Plan (WMP, in Appendix 8A) for the Project . This is to ensure that the recommendations and site-specific factors such as the designation of areas for the segregation and temporary storage of reusable and recyclable materials are to be implemented. This WMP should be submitted to the Engineer for approval. The framework of this WMP is included in Appendix 8A.

Measures to be undertaken during Planning & Design Stages to Reduce the Generation of Waste
8.7.2 Requirements for Waste Management Plan and proper sorting, re-use and recycling of C&DM shall be incorporated into the construction contracts.

8.7.3 Areas within the construction site shall be provided to allow for sorting and segregation of C&DM.
Measures to be undertaken during the Construction Stage to Reduce the Generation of Waste

8.7.4 A proper Waste Management Plan targeting i) waste identification; ii) waste minimization at source; iii) waste reuse & recycle; iv) waste segregation; and v) waste collection and disposal shall be implemented to ensure that wastes are adequately managed.

8.7.5 The various waste management options can be categorized in terms of preference from an environmental viewpoint. The preferred options have least impact and are more sustainable in the longer term. Hence, the following waste management hierarchy is recommended:
· Avoidance and minimization, i.e. not generating waste through improving practices and design.
· Reuse of materials, thus avoiding disposal (generally with only limited reprocessing).
· Recovery and recycling, thus also avoiding disposal (although reprocessing may be required).
· Treatment and disposal, according to relevant laws, guidelines and proper practices.

8.7.6 This hierarchy should be used to evaluate waste management options, thus allowing maximum waste reduction and reduced costs. Waste reduction measures should be introduced at the design stage and carried through the construction activities, wherever possible, by careful purchasing control, reuse of formwork and proper site management. By reducing or eliminating over-ordering of construction materials, waste generation is avoided, and costs are reduced both in terms of purchasing of raw materials and disposal of waste.

8.7.7 In particular, all waste materials shall be segregated into categories as follows:
· Inert portion of construction & demolition material (C&DM) for reuse on-site
· Surplus inert portion of C&DM to be used as public fill
· Remaining C&D waste for landfill
· Chemical waste
· General refuse

8.7.8 Training and instruction of construction staff should be given at the site to increase awareness and draw attention to waste management issues and the need to minimize waste generation. The training requirement should be included in the site Waste Management Plan.

8.7.9 On-site measures promoting proper segregation and disposal of construction waste should be implemented. These measures may include the provision of separate containers for inert (rubble, sand, stone, etc.) and non-inert (wood, organics, etc.) wastes. The inert waste should be re-used on site before being disposed of at public filling area, and the non-inert waste should be sorted for re-use or recycling before being transported to landfills.

8.7.10 Where waste generation is unavoidable, the potential for recycling or reuse should be explored and opportunities taken. If wastes cannot be recycled, disposal routes described in the WMP should be followed.
8.7.11 Training shall be provided to workers on the concepts of the site cleanliness and appropriate waste management procedure, including waste reduction, reuse and recycling.

8.7.12 Regular maintenance and cleaning of the waste storage areas shall be undertaken.
Measures to be undertaken during the Construction Stage to Manage the Handling and Disposal of Waste
General

8.7.13 To monitor the proper disposal of solid waste at landfills and public fill at public filling facilities, a trip-ticket system on all solid waste transfer/disposal operations should be included as one of the contractual requirements (as described in WBTC No. 5/99, which is to be replaced by WBTC No. 21/2002 in September 2002). The Independent Environmental Checker (IEC) should be responsible for auditing this system.

8.7.14 A record system documenting the amount of wastes generated, recycled and disposed; as well as disposal methods and sites should be implemented during the construction phase and audited by the IEC. Table 8.1 gives an example of a recording sheet to record the amount of wastes generated, recycles and disposed.

* Units for paper, steel, plastic, timber and refuse are in kg instead of m3.

8.7.15 All C&DM should be sorted on site into inert and non-inert components. Non-inert materials (C&D waste) such as wood, glass and plastic with not more than 30 % by weight of inert material are acceptable for disposal to a landfill, probably WENT. However, the Waste Reduction Framework Plan (WRFP) aims to reducing this figure to less than 20%. Inert materials (public fill) such as soil, rubble, sand, rock, brick and concrete should be separated and broken down to size suitable for subsequent filling. Steel and other metals should be recovered from the C&DM and recycled as far as practical if possible.

Storage, Collection and Transport of Waste

8.7.16 Licensed waste haulers should be employed to collect and transport waste to the appropriate disposal points. The following measures to minimize adverse impacts should be implemented:
· Handle and store waste in a manner which ensures that it is held securely without loss or leakage, thereby minimizing the potential for pollution;
· Use waste haulers authorized or licensed to collect specific categories of waste;
· Remove waste in a timely manner;
· Maintain and clean waste storage areas regularly;
· Minimize windblown litter and dust during transportation by either covering trucks or transporting waste in enclosed containers;
· Obtain the necessary waste disposal permits from the appropriate authorities, if they are required, in accordance with the Waste Disposal Ordinance (Cap 354), Waste Disposal (Chemical Waste) (General) Regulation (Cap 354), and the Land (Miscellaneous Provisions) Ordinance (Cap 28);
· Dispose of waste at licensed waste disposal facilities;
· Develop procedures such as a ticketing system to facilitate tracking of loads, particularly for chemical waste, and to ensure that illegal disposal of waste does not occur; and
· Maintain records of the quantities of waste generated, recycled and disposed.

Storage of Excavated Materials

8.7.17 Excavated materials may need to be temporarily stockpiled on-site. Control measures should be taken at the stockpiling area to prevent the generation of dust and pollution of water. Key control measures are highlighted below:
Dust Control
· Surface of stockpiled soil should be wetted with water when necessary especially during dry season.
· Stockpiled soil should be properly covered with tarpaulins.
· Disturbance of stockpiled soil should be minimized.
· Stockpiling areas should be enclosed if possible.
Water Quality Control
· An independent surface water drainage system equipped with silt traps should be installed at the stockpiling area.
· Stockpiled soil should be properly covered with tarpaulins during heavy rainstorms.
· Stockpiles of excavated materials should be placed in the location away from the shoreline.

Handling and Disposal of Dredged Materials

8.7.18 The sediment at pier sites would be dredged and transferred to barges for subsequent disposal. Release of dredged sediment into the surrounding water should be avoided. Close grabs should be used for sediment dredging. It is recommended that the distance between the barge and the dredging point be shortened as far as possible to avoid dropping of sediment from the close grab to the seawater.

8.7.19 Category H material was identified at sampling locations A14 and A15. These two locations were near the Hong Kong boundary. As there was no exceedance of 10xLCEL for the tested parameters, the sediment to be dredged in these locations should be disposed of at a confined marine disposal site. East Sha Chau mud pits are the designated disposal site for contaminated sediment and would be suitable for accepting this type of dredged material.

8.7.20 A total of 11 grab and vibrocore sediment samples were classified as Category M material. Biological testing was conducted to determine the disposal option (Type 1 open sea disposal at dedicated sites or Type 2 confined marine disposal) for Category M material. The disposal option for Category M material would be open sea disposal at dedicated sites if passing the biological tests or confined marine disposal if failing the test.

8.7.21 The sediment samples collected at A5, A6, A11 and D3 had failed the biological tests. A5, A6 and A11 were grab sediment samples whilst D3 were vibrocore sample. A5 and A6 were adjacent to D3 indicating high contaminant levels in that region. The proposed s-curve bridge alignment is likely to cut through this region. Sediment that needs to be dredged away during the bridge pier construction in this region should also adopt confined marine disposal. A11 is located further away from the bridge alignment and the sediment at A11 is not likely to be disturbed or dredged away during the construction of the SWC bridge.

8.7.22 Open sea disposal can be adopted for the sediment, which was classified as Category L material. Open sea disposal sites are the South Cheung Chau spoil disposal area and the East Ninepins spoil disposal ground. For Category M sediment, which passed the biological tests, open sea disposal at dedicated sites, i.e. empty marine borrow pits, should be adopted. Based on the SI results, these may include the sediment near sampling locations D1, D2, D4 - D8, A1 - A4, A7 - A10, A12, A13 and A16. Exhausted marine borrow pits such as the South Tsing Yi, North of Lantau, East Tung Lung Chau and the West of Brothers may accommodate this uncontaminated dredged material.

8.7.23 Dredged volume of one pier is about 650 m3. There would be in total about 78 piers for typical span (75m spacing) and a total volume of 50,700 m3. For navigation channel, the volumes of main pier and dolphin were estimated to be 2,800 m3 and 3,200 m3 respectively. The section of the SWC bridge within the HKSAR waters is about 3.2 km in length. With a typical span of 75m and a navigation channel of approximate 210m in length on the Hong Kong side, the estimated total volume of sediment to be dredged is about 57,000 m3. The sediment volumes for open sea disposal (at the South Cheung Chau spoil disposal area and the East Ninepins spoil disposal ground) and confined marine disposal (at East Sha Chau mud pits) would be approximately 34,500 m3 (a length of about 2,000 m with Category L material at D1, D2, D4, D5 and D6) and 22,500 m3 (a length of about 1,200 m with Category M material failing the biological test at D3 and Category H material at A14 near the alignment) respectively.

8.7.24 For the proposed enhancement measure of sediment dredging at inlet water channel, which is linked to Mai Po Gei Wai Nos. 16 and 17, and access route, the identified Category M material at GS1, GS4, GS6, GS10. GS11 and GS12 (assumed failing the biological tests) with a volume of about 4,400 m3 would be disposed of at confined marine disposal sites, i.e East Sha Chau mud pits. Similarly, the Category H material (<10xLCEL) at GS2, GS3, GS5, GS7, GS8 and GS9 with a volume of 4,400 m3 should also be disposed of at confined marine disposal sites.

C&D Material

8.7.25 In order to minimize waste generation and to keep the associated environmental impacts within acceptable levels, the following control measures should be adopted.

8.7.26 Careful design, planning and good site management can minimize over-ordering and generation of waste materials such as concrete, mortar and cement grouts. The design of formwork should maximize the use of standard wooden panels so that a high level of reuse can be achieved. Alternatives such as steel formwork or plastic facing should also be considered to increase the potential for reuse.

8.7.27 The contractor should recycle as much of the C&DM as possible on-site. Proper segregation of waste types on site will increase the feasibility of certain components of the waste stream by recycling companies. For example, concrete and masonry can be used as general fill, and rebars can be sold to steel mills. Different areas of the worksite should be designated for such segregation and storage wherever site conditions permit.

8.7.28 The handling and disposal of bentonite slurries, if any is used, should be undertaken in accordance within ProPECC PN 1/94 on construction site drainage.

8.7.29 In order to avoid dust or odour impacts, vehicles leaving the work site carrying C&D wastes or public fill should have their load covered. Vehicles should be routed as far from sensitive receivers in the area as possible.

8.7.30 C&D wastes with more than 30% inert material (by weight) should not be disposed of at landfills.

8.7.31 Effective from 1 July 1999, the Contractor must comply with the trip-ticket system for the disposal of C&DM (WBTC No. 5/99, which is to be replaced by WBTC No. 21/2002 in September 2002). Confirmation has to be sought from the Public Fill Committee (PFC) and EPD regarding the availability of public filling facilities or a landfill, for inert C&D waste and non-inert C&D waste, respectively.

8.7.32 Particular Specification for the construction contract of the Project shall include the following clauses with terminology as defined under WBTC No. 4/98:
· The Contractor shall produce a Construction and Demolition Material Disposal Delivery Form (the Form) for each and every vehicular trip transporting C&DM, i.e. public fill or C&D waste, off Site. The Contractor shall complete the Form in duplicate.
· Prior to the vehicle leaving the Site, the Contractor shall present to the site supervisory staff the completed Form. The site supervisory staff shall retain a copy of the Form and return the original to the Contractor. The Form shall be carried on board the vehicle at all times throughout the vehicular trip.
· For each vehicular trip, the Contractor shall obtain a receipt from the operator of the public filling facility or the landfill. The Contractor shall submit the original receipt to the Engineer's Representative within 5 working days of the vehicular trip. Late return without any acceptable reason might be regarded as non-compliance by the Engineer's Representative.
· The Contractor acknowledges and shall permit the Engineer Representative to request and obtain information from the operator of the Designated Disposal Tip verifying the receipt and the accuracy of the information on that receipt.
· All C&DM shall become the property of the Contractor when it is removed from the Site. The Contract should make provision that the Contractor will deliver material to the designated locations as agreed with CED.
· The Contractor will be required to complete the relevant details on a standard form and submit the form for stamping and collection by site supervisory staff and submit to Engineer Representative the receipt issued by the operator of the public filling facility/landfill after the disposal of the C&DM. Details to be included on the standard form and the receipt are specified in WBTC No. 5/99 (to be replaced by 21/2002 in September 2002).

Chemical Waste

8.7.33 For those processes that generate chemical waste, it may be possible to find alternatives which generate reduced quantities or even no chemical waste, or less dangerous types of chemical waste.

8.7.34 Chemical waste, as defined by Schedule 1 of the Waste Disposal (Chemical Waste) (General) Regulation (CWR), should be handled in accordance with the Code of Practice on the Packaging, Handling and Storage of Chemical Waste published by the EPD. The producer of chemical wastes should be registered as chemical waste producer in accordance with the CWR.

8.7.35 Containers used for the storage of chemical waste should:

· be suitable for the substances to be held, resistant to corrosion, maintained in good condition, and securely closed;
· have a capacity of less than 450 liters unless the specifications have been approved by the EPD; and
· display a label in English and Chinese in accordance with instructions prescribed in Schedule 2 of the CWR.

8.7.36 The storage area for chemical waste should:
· be clearly labeled and used solely for the storage of chemical waste;
· be enclosed on at least three sides;
· have an impermeable floor and bunding, of capacity to accommodate 110% of the volume of the largest container or 20% by volume of the chemical waste stored in that area, whichever is the greatest;
· have adequate ventilation;
· be covered to prevent rainfall entering (water collected within the bund must be tested and disposed as chemical waste if necessary); and
· be arranged so that incompatible materials are adequately separated.

8.7.37 Disposal of chemical waste should be:
· via a licensed waste collector; and
· at a recycling, treatment or disposal facility that is licensed under the Waste Disposal Ordinance to receive chemical waste, such as the Chemical Waste Treatment Centre in Tsing Yi.

8.7.38 With the implementation of the above measures, potential environmental impacts from the storage, handling and disposal of a small amount of chemical waste generated by the construction activities of the Project would be negligible.

General Refuse

8.7.39 General refuse should be stored in enclosed bins or compaction units separate from C&DM and chemical wastes. A reputable waste collector should be employed by the contractor to remove general refuse from the site, separate from C&DM and chemical wastes, and on regular basis in order to minimize odour, pest and litter impacts. The burning of refuse at site is not permitted under the Air Pollution Control Ordinance (Cap. 311).

8.7.40 Reusable rather than disposable dishware should be used if feasible. Aluminium cans can often be recovered from the waste stream by recyclers if these are segregated or if access is provided. Labelled bins for the deposit of aluminium cans should be provided if feasible.

8.7.41 Office waste can be reduced through recycling of paper if volumes are large enough to warrant collection. Participation in a local collection scheme should be considered if one is available.

8.7.42 Good management practices should be implemented to ensure that refuse is properly stored and is transported for disposal of at licensed landfills, i.e. WENT.

8.8 Evaluation of Residual Impacts

8.8.1 The key concern of waste generation is during the construction period. The estimated volumes of C&D material and chemical waste were small. Recycle and reuse of C&D material minimises the potential impacts from construction waste generation. Chemical waste would be stored, handled, transported and disposed in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Waste issued by EPD. Disposal of chemical waste, if any, would be at a licensed chemical waste treatment and disposal facility, the potential impacts arising from chemical waste generation are minimal.

8.8.2 General refuse would be stored and transported by licensed waste collector for off site disposal at licensed landfills. With proper handling of general refuse, there would be no unacceptable environmental impacts.

8.8.3 The outlets of marine dredged material from the pier sites have been identified to be at open sea disposal sites, i.e. the South Cheung Chau spoil disposal area and the East Ninepins spoil disposal ground, for uncontaminated sediment and at confined marine disposal site, i.e. East Sha Chau mud pits, for contaminated sediment. Disposal of the dredged material from the inlet channel and the proposed access route at Mai Po is conservatively assumed to be at confined marine disposal site, i.e. East Sha Chau mud pits. Disposal of the sediment at designated disposal sites would ensure the environmental impacts are minimal.

8.8.4 The mitigation measures described in this section are practical, proven, and cost-effective means for controlling potential impacts from wastes. Provided that these measures are adopted and properly implemented during the construction phase of the Project, the residual impacts are expected to be minimal. Operational impacts from the SWC are also expected to be minimal.

8.9 Environmental Audit

8.9.1 Auditing of each waste stream should be carried out periodically to determine if waste is being managed in accordance with prescribed procedures and the Waste Management Plan. The audits should examine all aspects of waste management including waste generation, storage, recycling, treatment, transportation, and disposal. The general site inspections including waste management issues will be undertaken weekly by Environmental Team to check all construction activities for compliance with all appropriate environmental protection and pollution control measures, including those set up in the WMP. Meanwhile, waste management audit will be carried out on monthly basis by the IEC. Details of waste audit are further described in Chapter 14 (Environmental Monitoring and Audit).

8.10 Conclusions

8.10.1 An assessment of potential environmental impacts from wastes of the SWC project has been conducted. Key issues are the requirements for effective waste management planning during the construction phase. The operational phase is not expected to generate any amount of wastes.

8.10.2 Waste management methods and practices and other environmental control measures for the construction phase have been recommended to ensure that potential impacts are avoided or mitigated to acceptable levels. Provided all the suggested mitigation measures are properly implemented, potential environmental impacts associated with wastes from the Project would be insignificant. The framework of the Waste Management Plan is included in this section. The Contractor should prepare full details of the Waste Management Plan based on the proposed framework.