6.2 Environmental Legislation, Policies, Plans, Standards and Criteria. 1

6.4 Baseline Conditions. 7

6.5 Identification of Potential Sources of Impact 8

6.6 Prediction and Evaluation of Environmental Impacts. 9

6.7 Mitigation Measures. 10

6.8 Evaluation of Residual Impacts. 14

6.9 Environmental Audit 14

6.10 Conclusion. 14

6 WASTE management

6.2 Environmental Legislation, Policies, Plans, Standards and Criteria

6.2.1 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 Ordinance (EIAO-TM), respectively.

6.2.2 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

6.2.3 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.

6.2.4 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.

6.2.5 The Public Cleansing and Prevention of Nuisances Regulation provides control on illegal tipping of wastes on unauthorised (unlicensed) sites

Dredged Marine Sediment

6.2.1 The ETWB TCW No. 34/2002 sets out the procedure for seeking approval to dredge / excavate sediment and the management framework for marine disposal of dredged / excavated sediment. This Technical Circular outlines the requirements to be followed in assessing and classifying the sediment and explains the marine disposal arrangement for the classified material. The sediment quality criteria for the classification of sediment are presented in Table 6.1.

6.2.2 Dumping permits from EPD are required for marine disposal of dredged materials.

Chemical Waste

6.2.3 Under the Waste Disposal (Chemical Waste) (General) Regulations, all producers of chemical waste must register with EPD and treat their wastes, either utilising on-site plant licensed by EPD, or arranging for a licensed collector to transport the wastes to a licensed facility. The regulation also prescribes the storage facilities to be provided on site, including labelling and warning signs, and requires the preparation of written procedures and training to deal with emergencies such as spillages, leakages or accidents arising from the storage of chemical wastes.

Construction and Demolition (C&D) Materials

6.2.4 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.

6.2.5 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.

6.2.6 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 50,000m³ or importing fill material less than 50,000m³ are exempt from the C&DMMP. The new ETWB TCW No. 19/2005 “Environmental Management on Construction Sites” includes procedures on waste management requiring contractors to reduce the C&D material to be disposed of during the course of construction. Under ETWB TCW No. 19/2005, the Contractor is required to prepare and implement an Environmental Management Plan (EMP) and the WMP becomes part of the EMP.

6.3 Assessment Methodology

General

6.3.1 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 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.

Dredged Marine Sediment

6.3.2 The Phase I marine site investigation works of WDII commenced on 25 August 2006 and were completed on 14 September 2006 and included laboratory testing of contaminants to determine the level of contamination in the marine sediments at the proposed reclamation. The works included vibrocoring in the HKCEC sea channel, the Causeway Bay typhoon shelter, North Point waterfront and the proposed temporary typhoon shelter to obtain sediment samples for chemical testing (Figure 6.1). The Phase II marine site investigation works commenced on 27 September 2006 and were completed on 10 October 2006 and included sampling locations to the west and east of the HKCEC and in the Wanchai Public Cargo Working Area (PCWA) basin (Figure 6.1). Permission to sample in the WSD prohibition zone and MTR protection zone in the area to the west of HKCEC was not obtained from WSD and MTRC for the Phase II marine site investigation. In addition, MTRC advised that anchoring is not permitted within 20m of their protection zone and hence it was not possible to carry out sampling at the proposed locations.

Chemical Testing

6.3.3 Each sub-sample recovered from the Phase I and II vibrocoring was tested in the laboratory for the following parameters:

(i) Metal and metalloid concentrations including chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), cadmium (Cd), nickel (Ni), zinc (Zn), silver (Ag) and arsenic (As)

(ii) Concentrations of organic compounds including total polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs)

6.3.4 Grab samples collected from the vibrocoring locations were tested for tributyltin (TBT) in interstitial water. Grab samples were used in view of the difficulty to extract sufficient interstitial water for the TBT analysis in the vibrocore samples to achieve the required detection limit, as was encountered in the EIA study for Wan Chai Development Phase II Comprehensive Feasibility Study.[1]

6.3.5 Elutriate tests were conducted to assess the likelihood of release of contaminants from sediment to the water, when the seabed is disturbed during dredging. If the contaminant levels are higher in the elutriates in comparison with the sample of marine water from the same site, it can be concluded that the contaminants are likely to be released into the open waters during dredging activities. The potential water quality impacts associated with the dredging of sediment are discussed in Section 5 of this Report.

6.3.6 Under the management and classification system, dredged sediments destined for marine disposal are classified according to their level of contamination by 13 contaminants (Table 6.1).

^{Table 6.1 Sediment Quality
Criteria for the Classification of Sediment}

Contaminants	LCEL	UCEL
*Heavy Metal (mg/kg dry weight)*
Cadmium (Cd)	1.5	4
Chromium (Cr)	80	160
Copper (Cu)	65	110
Mercury (Hg)	0.5	1
Nickel (Ni)	40	40
Lead (Pb)	75	110
Silver (Ag)	1	2
Zinc (Zn)	200	270
*Metalloid (mg/kg dry weight)*
Arsenic	12	42
*Organic-PAHs (µg/kg dry weight)*
PAHs (Low Molecular Weight)	550	3160
PAHs (High Molecular Weight)	1700	9600
*Organic-non-PAHs (µg/kg dry weight)*
Total PCBs	23	180
*Organometallics (µg-TBT L^-1 in interstitial water)*
Tributyltin	0.15	0.15

Source: Appendix A of ETWB TCW No. 34/2002 Management of Dredged / Excavated Sediment

Note: LCEL – Lower Chemical Exceedance Level

UCEL – Upper Chemical Exceedance Level

6.3.7 Sediments are categorised with reference to the LCEL and UCEL, as follows:

Category L Sediment with all contaminant levels not exceeding the LCEL. The material must be dredged, transported and disposed of in a manner that minimises the loss of contaminants either into solution or by suspension.

Category M Sediment with any one or more contaminant levels exceeding the LCEL and none exceeding the UCEL. The material must be dredged and transported with care, and must be effectively isolated from the environment upon final disposal unless appropriate biological tests demonstrate that the material will not adversely affect the marine environment.

Category H Sediment with any one or more contaminant levels exceeding the UCEL. The material must be dredged and transported with great care, and must be effectively isolated from the environment upon final disposal.

6.3.8 In the case of Category M and Category H contamination, the final determination of appropriate disposal options, routing and the allocation of a permit to dispose of material at a designated site will be made by EPD and the Marine Fill Committee (MFC) in accordance with the ETWB TCW No. 34/2002 .

Biological Testing

6.3.9 For Category M sediment, Tier III biological screening was carried out to determine the appropriate disposal methods in accordance with the requirements of ETWB TCW No. 34/2002:

(i) a 10‑day burrowing amphipod toxicity test

(ii) a 20‑day burrowing polychaete toxicity test

(iii) a 48‑96 hour larvae (bivalve) toxicity test.

6.3.10 Sediment classified as Category H with one or more contaminant levels exceeding 10 times the LCEL were also subjected to the above three biological tests but in a diluted manner (dilution test).

6.3.11 The species used for each type of biological test and the test conditions are listed in Table 6.2 below.

^{Table 6.2 Test Species for Biological Testing}

Test Types	Species	Reference Test Conditions^*
10‑day burrowing amphipod toxicity test	Leptocheirus plumulosus	U.S.EPA (1994)
20‑day burrowing polychaete toxicity test	Neanthes arenaceodentata	PSEP (1995)
48‑96 hour bivalve larvae toxicity test	Mytilus spp. or Crassostrea gigas	PSEP (1995)

Notes:*

(i) U.S.EPA (U.S. Environmental Protection Agency) 1994. Methods for assessing the toxicity of sediment-associated contaminants with estuarine and marine amphipods. Office of Research and Development. U.S. Environmental Protection Agency, Cincinnati, OH. EPA/600/R94/025.

(ii) PSEP (Puget Sound Estuary Program) 1995. Recommended guidelines for conducting laboratory bioassays on Puget Sound sediments.

6.3.12 Sediment samples were characterized by the testing laboratory for ancillary testing parameters such as porewater salinity, ammonia, TOC, grain size and moisture content. This provided necessary information on the general characteristics of the sediment. The test endpoints and decision criteria are summarized in Table 6.3. The sediment was deemed to have failed the biological testing if it failed in any one of the three toxicity tests.

^{Table 6.3 Test Endpoints and Decision Criteria for
Biological Testing}

Toxicity test	Endpoints measured	Failure criteria
10-day amphipod	Survival	Mean survival in test sediment is significantly different (p £ 0.05)¹from mean survival in reference sediment and mean survival in test sediment < 80% of mean survival in reference sediment.
20-day polychaete	Dry Weight²	Mean dry weight in test sediment is significantly different (p £ 0.05)¹from mean dry weight in reference sediment and mean dry weight in test sediment < 90% of mean dry weight in reference sediment.
48-96 hour bivalve larvae	Normality Survival³	Mean normality survival in test sediment is significantly different (p £ 0.05)¹from mean normality survival in reference sediment and mean normality survival in test sediment < 80% of mean normality survival in reference sediment.

¹Statistically significant differences should be determined using appropriate two-sample comparisons (e.g., t-tests) at a probability of p £ 0.05.

²Dry weight means total dry weight after deducting dead and missing worms.

³ Normality survival integrates the normality and survival end points, and measures survival of only the normal larvae relative to the starting number.

6.4 Baseline Conditions

Existing Sediment Characteristics

6.4.1 The results of the marine sediment quality analysis from the Phase I and Phase II marine site investigation works, as compared with the sediment quality criteria for the classification of sediment, are presented in Appendix 6.1. All testing results of TBT in interstitial water were below the reporting limit of 0.015 µg/L. The practical limitation of being unable to carry out the TBT interstitial water test is therefore not considered to have any significant effect.

6.4.2 The sediment testing results indicate that Category H sediment was found at the HKCEC sea channel and to the immediate west of the sea channel. At grab sample V06-7, the reported contaminant level of Ag exceeded the LCEL by 10 times.

6.4.3 Along the Wan Chai waterfront, the sediment testing results indicate that Category H sediment was found at all eight vibrocoring locations. At vibrocores V06-14 and V06-17, Category H sediment with contaminant levels exceeding the LCEL by 10 times was reported for Ag. Category M sediment was found at V06-13B.

6.4.4 Tier III biological screening was conducted for the Category M sediment sample (found at V06-13B), and the Category H sediment samples with the reported contaminant levels exceeding the LCEL by 10 times i.e. >10xLCEL, as described above. The results of the biological screening are summarized in Table 6.4 below.

^{Table 6.4 Results
of Biological Screening of Category M and Category H (>10xLCEL) Samples}

Vibrocore No. / Depth	Location	Amphipod Test	Polychaete Test	Bivalve Test	Result of Biological Screening	Classification
V06-7 grab	HKCEC sea channel	Ö	Ö	Ö	Pass	Category H
V06-13B 0-0.9m	Wanchai waterfront	Ö	Ö	Ö	Pass	Category M
V06-14 0-0.9m	Wanchai waterfront	Ö	Ö	Ö	Pass	Category H
V06-17A 0-0.9m	Wanchai waterfront	Ö	Ö	Ö	Pass	Category H

Notes:

1. X = fail biological test

2. Ö = pass biological test

6.5 Identification of Potential Sources of Impact

6.5.1 The construction activities to be carried out for the proposed sewage outfall 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:

· Marine dredged sediment

· C&D material

· Chemical waste

· General refuse

6.5.2 Each type of waste arising is described below, together with an evaluation of the potential environmental impacts associated with the generation, handling, storage and transport of the waste.

6.5.3 Each type of waste arising is described below, together with an evaluation of the potential environmental impacts associated with the generation, handling, storage and transport of the waste.

6.6 Prediction and Evaluation of Environmental Impacts

Dredged Marine Sediment

6.6.1 The seabed would be dredged for sewage outfall construction. The total volume of dredged sediment for the outfall is estimated to be approximately 0.06 Mm³. Based on the results of the chemical and biological screening, the estimated volume of contaminated dredged sediment (Category M and H) requiring Type 2 confined marine disposal is approximately 0.024 Mm³, and the estimated volume of Category L sediment suitable for open sea disposal is approximately 0.036 Mm³.The final disposal site will be determined by the MFC and a dumping licence will be obtained from EPD prior to the commencement of the dredging works.

6.6.2 To minimise any potential adverse impacts arising from the dredged marine sediment, the sediment should be dredged, transported and disposed of in a manner that would minimise the loss of contaminants either into solution or by resuspension. Mitigation measures to minimise potential environmental impacts are recommended in Section 6.7. Since the dredging activities are marine based activities and negligible dust impacts on nearby air sensitive receivers would be expected. The findings of the noise impact assessment presented in Section 4 of this report indicated that adverse noise impact would not be expected during the course of the dredging activities.

6.6.3 Mitigation measures to minimise potential environmental impacts are recommended in Section 6.7. With the implementation of mitigation measures, no unacceptable impacts would be expected from the transportation and disposal of the dredged sediment.

Construction and Demolition Materials

6.6.4 It is expected that limited amount of C&D material (less than 500 m³) will be generated during the construction of the Cross-harbour water mains. Part of the existing submarine Cross-harbour water mains will be buried underneath the HKCEC reclamation after decommissioning and the remaining pipelines will be left underneath the existing seabed. The amount of C&D material expected to be generated will be quantified in the site Waste Management Plan to be prepared by the Contractor. Since the construction activities will be located within Victoria Harbour, improper management of C&D materials may introduce debris and pollutants to the harbour waters, and mitigation measures will be required (refer to Section 6.7).

Chemical Waste

6.6.5 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.

6.6.6 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

6.6.7 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 6.7. 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

6.6.8 The construction workforce would generate general refuse comprising food scraps, waste paper, empty containers, etc. As the introduction of these wastes is likely to have detrimental effects on water quality in the area, 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, flushed or leached into the marine environment, or creating an odour nuisance. The waste storage area should be well maintained and cleaned regularly so as to prevent from attracting pests and vermin to the work sites.

6.6.9 The maximum number of construction workers to be employed is estimated to be about 80 workers. Based on a generation rate of 0.65 kg per worker per day, the maximum daily arising of general refuse during the construction period would be approximately 56 kg. With the implementation of waste management practices at the site (as recommended in Section 6.7), adverse environmental impacts would not be expected from the storage, handling and transportation of refuse.

6.7 Mitigation Measures

Dredged Marine Sediments

6.7.1 The basic requirements and procedures for dredged mud disposal are specified under the ETWB TCW No. 34/2002. The MFC is responsible for the provision and management of disposal capacity for dredged/excavated sediment, and DEP is responsible for the issue of permits for marine disposal under the provisions of the Dumping at Sea Ordinance (Cap. 466).

6.7.2 The dredged marine sediments would be loaded onto barges, transported to and disposed of at the designated disposal sites at South of Cheung Chau, East of Ninepin, East of Tung Lung Chau, South of Tsing Yi and East of Sha Chau to be allocated by the MFC depending on their level of contamination or at other disposal sites after consultation with the MFC and EPD. Based on the chemical screening results, the majority of the marine sediment to be dredged was classified as contaminated and would require Type 2 confined marine disposal. In accordance with the ETWB TCW No. 34/2002, the contaminated material must be dredged and transported with great care, and the mitigation measures recommended in Section 5 of this Report should be strictly followed. Furthermore, the dredged contaminated sediment must be effectively isolated from the environment upon final disposal and the project proponent will consult the MFC about the disposal requirement.

6.7.3 It will be the responsibility of the Contractor to satisfy the appropriate authorities that the contamination levels of the marine sediment to be dredged have been analysed and recorded. According to the ETWB TCW No. 34/2002, this will involve the submission of a formal Sediment Quality Report to the DEP, at least 3 months prior to the dredging contract being tendered.

6.7.4 During transportation and disposal of the dredged marine sediments requiring Type 1 and Type 2 disposal, 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.

· 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 DEP.

· Barges or hopper barges shall not be filled to a level that would cause the overflow of materials or sediment laden water during loading or transportation.

Good Site Practices

6.7.5 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.

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

Waste Reduction Measures

6.7.6 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:

· Sort C&D waste from demolition of the existing structures to recover recyclable portions such as metals.

· 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.

· Use of reusable non-timber formwork to reduce the amount of C&D material.

· 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.

6.7.7 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

6.7.8 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

6.7.9 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

6.7.10 The C&D material should be sorted on-site into inert C&D material (that is, public fill) and C&D waste. 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 as far as practicable. All the suitable (inert) material should be broken down to 250 mm in size for reuse as public fill and surcharge 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 be designated to facilitate the sorting process and a temporary stockpiling area will be required for the separated materials.

6.7.11 In order to monitor the disposal of public fill and C&D waste at public filling facilities and landfills, respectively, 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 Independent Environmental Checker should be responsible for auditing the results of the system.

6.7.12 Table 6.6 provides a summary of the various waste types likely to be generated during the construction phase, together with the recommended handling and disposal methods.

^{Table 6.6 Summary
of Waste Handling Procedures and Disposal Routes}

Waste Type	Generated from Works Item	Total Quantity Generated	Quantity to be disposed off-site / re-used	Handling	Disposal
C&D Material	Demolition of structures	< 500m³	< 500m³	Sort on-site into : · Inert C&D material (public fill) · C&D waste	Suitable material broken down to 200mm in size for reuse as public fill and reuse of removed temporary reclamation in WDII reclamation or to be disposed to public fill reception facilities for other beneficial uses C&D waste to be reused or recycled and, as a list resort, disposed to landfill
Dredged Sediments	Category H and Category M sediment	0.024 Mm³	0.024 Mm³	Techniques to minimise resuspension (closed grabs, tight seal on barges, controlled loading and transfer)	Type 2 confined marine disposal - contaminated mud pit (approx. 0.024 Mm³)
Dredged Sediments	Category L sediment	0.036 Mm³	0.036 Mm³		Type 1 open sea disposal - gazetted marine disposal ground (approx. 0.036 Mm³)
Chemical Wastes	Cleansing fluids, solvent, lubrication oil and fuel from construction plant and equipment	Few cubic metres per month (preliminary estimate)	Few cubic metres per month (preliminary estimate)	Recycle on-site or by licensed companies Stored on-site within suitably designed containers	Chemical Waste Treatment Facility or other licensed facility
General Refuse	Waste paper, discarded containers, etc. generated from workforce	approx. 52 kg per day (preliminary estimate based on workforce of 80)	approx. 52 kg per day	Provide on-site refuse collection points	Refuse station for compaction and containerisation and then to landfill

6.8 Evaluation of Residual Impacts

6.8.1 With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste arisings, no adverse residual impact is expected to arise during the construction of the proposed Project.

6.9 Environmental Audit

6.9.1 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 mitigation measures recommended in Section 6.7 should form the basis of the site Waste Management Plan to be developed by the Contractor in the construction stage.

6.10 Conclusion

6.10.1 A review of the sediment quality data from the marine ground investigation indicated that the majority of marine sediments to be dredged for the project were classified as contaminated. The total dredged volume during the construction of the Cross-harbour water mains was estimated as approximately 0.06 Mm³, of which 0.024 Mm³was classified as contaminated (Category M and H) requiring Type 2 confined marine disposal, and 0.036 Mm³was classified as Category L and would be suitable for Type 1 open sea disposal. With the implementation of the recommended mitigation measures in accordance with the requirements of ETWB TCW No. 34/2002, no adverse residual impact was predicted. Since the dredging activities are marine based activities and negligible dust impacts on nearby air sensitive receivers would be expected. The findings of the noise impact assessment in Section 4 of this report indicated that adverse noise impact would not be expected during the course of the dredging activities.

6.10.2 Wastes generated by the construction activities will include C&D material, general refuse from the workforce and chemical waste from the maintenance of construction plant and equipment. C&D material with suitable characteristics would be reused on-site as far as practicable. Surplus material would require disposal to designed public filling facilities. Provided that these identified waste arisings are handled, transported and disposed of using approved methods and that recommended good site practice are strictly followed, adverse environmental impacts of air and odour emissions, noise, potential hazards, wastewater discharge and transport would not be expected during the construction phase.

[1] All testing results of TBT in interstitial water were below the reporting limit of 0.015 µg/L. The practical limitation of being unable to carry out the TBT interstitial water test is therefore not considered to have any significant effect.