3.4 Waste Management Impact Assessment

3.5 Mitigation of Adverse Impacts

3.6 Assessment of Residual Impacts

3.7 Environmental Monitoring and Audit

3.8 Conclusion

3.9 References

3 Waste & Materials Management

3.1 Introduction

3.1.1.1 This section identifies the potential wastes arising from the construction and operation of the Hong Kong Offshore Wind Farm in Southeastern Waters and assesses the environmental impacts associated with the handling and disposal of wastes and materials.

3.1.1.2 The Project is located offshore in a relatively exposed wind / wave environment, and in waters some 30 metres deep set above a seabed comprising of fine silty materials. These exposed conditions introduce particular constraints into the construction methodology and programme (Section 2 refers) and demand that the Project is developed in an effective and efficient manner during time periods when access to the site area is available.

3.1.1.3 A core element of this philosophy has been maximize prefabrication of elements and hence to avoid / minimise on-site waste generation where practicable to preclude adverse impacts on water quality and marine sensitive receivers.

3.2 Objectives

3.2.1.1 With reference to Clause 3.4.5.2 of the Environmental Study Brief (ESB), the assessment of waste / materials management includes the following:

(i) Analysis of Activities and Waste Generation

3.2.1.2 Identification of the quantity, quality and timing of waste arising from construction activities, and design, layout, construction methods and programmes adopted to minimise waste generation.

(ii) Proposal for Waste management

a) Prior to considering the disposal options for various types of wastes, opportunities for reducing waste generation, on-site or off-site re-use and recycling shall be evaluated.

b) Quantities of the wastes required to be disposed of as a consequence shall be estimated and the disposal options for the wastes shall be described in detail.

3.3 Legislation, Standards & Guidelines

3.3.1.1 The following legislation and evaluation criteria are relevant to the treatment and disposal of the wastes generated from the construction and operational phases of the Project:

· Waste Disposal Ordinance (Cap 354)

· Waste Disposal (Chemical Waste) (General) Regulation (Cap 354C)

· Dumping at Sea Ordinance (Cap 466)

· Environment, Transport and Works Bureau Technical Circular No. 34/2002 – Management of Dredged / Excavated Sediment

· Shipping and Port Control Ordinance (Cap 313)

3.3.2 Waste Disposal Ordinance (Cap 354)

3.3.2.1 The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes, with waste defined as any substance or article that is abandoned. Construction waste is defined as any substance or article, generated from construction work and abandoned, whether or not it has been processed or stockpiled before being abandoned. It does not include any sludge, screening or matter removed in or generated from any desludging, desilting or dredging works.

3.3.2.2 WDO stipulates the requirements for licenses related to the handling and disposal of waste. It specifies that only waste collection and transportation licensees are permitted to collect and transport wastes except for construction and trade related wastes where licenses are exempted. Furthermore, all wastes should only be abandoned / disposed at designated / licensed waste disposal sites.

3.3.3 Waste Disposal (Chemical Waste) (General) Regulation (Cap 354C)

3.3.3.1 Chemical waste as defined under the Waste Disposal (Chemical Waste) (General) Regulation includes any substance being scrap material, or unwanted substances specified under Schedule 1 of the Regulation, if the specified substance or chemical occurs in such a form, quantity or concentration so as to cause pollution or constitute a danger to health or risk of pollution to the environment.

3.3.3.2 A person should not produce, or cause to be produced, chemical wastes without registration with the Director of Environmental Protection (DEP). Chemical wastes must either be treated at an onsite facility licensed by EPD or be collected by a licensed collector for off-site treatment at a licensed facility. The waste producer, collector and disposal facility must each complete a trip ticket for each waste consignment to allow the transfer of wastes to be traced from cradle-to-grave.

3.3.3.3 The EPD Regulation prescribes storage facilities to be provided on site, which include labelling and warning signs. To reduce the risks of pollution and danger to human health or life, the waste producer is required to prepare and make available written emergency procedures for spillage, leakage or accidents arising from the storage of chemical wastes. Waste producers must also provide their employees with training on such procedures.

3.3.4 Dumping at Sea Ordinance (Cap 466)

3.3.4.1 This Ordinance came into operation in April 1995 and empowers the DEP to control the disposal and incineration of substances and articles at sea for the protection of the marine environment. Under the Ordinance, a permit from the DEP is required for the disposal of regulated substances within and outside the waters of the Hong Kong SAR. The permit contains terms and conditions that include the following specifications:

· Type and quantity of substances permitted to be dumped;

· Location of the disposal grounds;

· Requirement of equipment for monitoring the disposal operations; and

· Environmental monitoring requirements.

3.3.5 Environment, Transport and Works Bureau Technical Circular No. 34/2002 – Management of Dredged / Excavated Sediment

3.3.5.1 Associated with the Dumping at Sea Ordinance, the Environment, Transport and Works Bureau Technical Circular No. 34/2002 on the Management of Dredged / Excavated Sediment (ETWB 34/2002) sets out the procedures for seeking approval to dredge / excavate sediment and the management framework for sediment disposal.

3.3.5.2 In accordance with ETWB 34/2002 criteria, sediment may be classified into one of three categories based on its contamination levels:

l Category L: Sediment with all contaminant levels not exceeding the Lower Chemical Exceedance Limit (LCEL). The material must be dredged, transported and disposed of in a manner that reduces the loss of contaminants either into solution or by re-suspension.

l Category M: Any one or more contaminants in the sediment exceeding the LCEL with none exceeding the Upper Chemical Exceedance Limit (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.

l Category H: Any one or more contaminants in the sediment exceeding the UCEL. The material must be dredged and transported with great care, and must be effectively isolated from the environment upon final disposal.

3.3.5.3 Table 3.1 presents the criteria for determining the quality of dredged sediment arising from Project development.

Table 3.1 ETWB 34/2002 Criteria for Dredged Sediment Classification

Parameters	LCEL	UCEL
Metals (mg/kg dry wt.)
Cadmium	1.5	4
Chromium	80	160
Copper	65	110
Mercury	0.5	1
Nickel	40	40
Lead	75	110
Silver	1	2
Zinc	200	270
Arsenic	12	42
Organic PAHs (mg/kg dry wt.)
Low Molecular Weight PAHs	550	3160
High Molecular Weight PAHs	1700	9600
Organic non-PAHs (mg/kg dry wt.)
Total PCB*	23	180
Organometalics (mgTBT / L in interstitial water)
Tributyl-tin^{^}	0.15	0.15

Notes: * Total PCBs comprises various congeners of PCB as referred in ETWB 34/2002
^ Contamination levels > 0.15 mg/L are assumed to exceed the UCEL

3.3.6 Shipping and Port Control Ordinance (Cap 313)

3.3.6.1 This Ordinance prohibits pollution of the sea by oil from land-based as well as marine sources, and also the dumping of refuse and general littering from vessels or port-based operations.

3.3.7 Other Relevant Guidelines

3.3.7.1 Other guideline documents which detail how the Contractor will comply with the WDO and its associated regulations include:

· Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), published by Environmental Protection Department (EPD); and

· Technical Circular (Works) No.12/2000, Fill Management, published by Environment, Transport and Works Bureau.

3.4 Waste Management Impact Assessment

3.4.1 Introduction

3.4.1.1 The key sources and types of waste potentially associated with the Project’s development include the following:

· Dredged marine sediment associated with installation of the transmission cable in Junk Bay.

· Chemical waste from off-site fabrication of the turbine and maintenance activities.

· Sewage from the construction and maintenance workforce.

· General refuse associated with construction and maintenance activities, such as food waste and packaging materials.

3.4.1.2 The following sections review the nature of these wastes.

3.4.2 Dredged Marine Sediment

3.4.2.1 A major component of the Project is the electricity transmission cable that shall be installed under the seabed, linking the offshore transformer station with the sub-station on land in Junk Bay. Compared with the offshore elements of the Project, Inner Junk Bay is exposed to a relatively high level of marine traffic activity in relatively shallow waters. This situation means there is greater potential for marine vessel anchor drag upon the seabed, and accordingly protective measures are required for the transmission cable section in this area. Figure 3.1 defines the location of the cable sections.

3.4.2.2 Two options for cable protection have been considered as introduced in sub-section 2.7.5:

· Dredging a trapezoidal trench ~3.0km long and approximately 3m deep in which to place the cable, with rock armour protection placed at the upper section level with the adjacent seabed. Figure 3.2 presents the concept.

· Installing the transmission cable by high-pressure water jetting, with concrete slabs placed level with the adjacent seabed to provide necessary cable protection.

3.4.2.3 The dredging option would involve the excavation and disposal of approximately 135,000m³ of marine mud. While both cable protection options have been kept open at this planning stage for a final decision to be made subject to detailed engineering design, for the purposes of this EIA Study report it is conservatively assumed that cable installation works in Inner Junk Bay will involve marine dredging. There are no other marine dredging works associated with the Project.

3.4.2.4 In order to characterize the marine sediment in the Study Area, a sampling and analysis programme was conducted in accordance with ETWB 34/2002. The first task involved a desktop review of existing sediment quality data for the potential dredging zone. Reference has been made to data from EPD’s routine marine sediment quality monitoring programme and from relevant EIA Studies.

3.4.2.5 Table 3.2 displays the latest published EPD data that covers the four sampling events during 2003 - 2006. Figure 3.3 displays the locations of the historical sediment quality monitoring stations.

3.4.2.6 The sediment at EPD monitoring station “JS2” located closest to the shore is classified as ‘Category H’ as levels of both copper and silver are greater than the UCEL. Sediment quality at EPD monitoring stations “ES1” and “ES4” is classed as ‘Category M’ due to levels of copper and silver above the LCEL, while sediment at EPD monitoring station “ES2” is classed as ‘Category L’ as levels of all parameters are below the LCEL.

3.4.2.7 This distribution reflects a general trend of decreasing contamination with increasing distance from historical sources in Junk Bay, appreciating that within the near-shore Eastern Harbour area there will inevitably be:

· Local hydrodynamic effects of sediment / pollution transport away from the source within the confines of the Eastern Harbour; and

· Discrete historical sources of localised pollution in areas fringing the Harbour.

3.4.2.8 For example, the Mercury concentration at station “ES1” is greater than at station “JS2”, although contamination is nonetheless still confined to the Eastern Harbour.

3.4.2.9 Table 3.3 displays additional sediment quality data for Junk Bay derived from a recent EIA (Maunsell, 2005) which confirms the generally contaminated status of marine sediment in inshore areas of the Bay (Figure 3.3 also displays these locations).

Table 3.2 Routine Marine Sediment Quality Monitoring Data (EPD, 2003 – 2006)

Sampling Location	Sampling Date	Metals and Metalloid Content (mg/kg)									Organics (µg/kg)			Nutrients (mg/kg)
		Cd	Cr	Cu	Ni	Pb	Zn	Hg	As	Ag	LMW PAHs^	HMW PAHs	PCBs	NH3-N	TKN
JS2	5 Jul 06	0.1	49	98	24	52	160	0.24	7.9	2	183	210	18	8.6	460
	3 Jan 06	0.2	47	95	25	51	150	0.41	7.3	2	194	402	18	0.76	480
	1 Aug 05	0.2	48	120	20	53	150	0.28	7.1	2	195	381	18	6.2	470
	2 Feb 05	0.2	52	120	24	52	160	0.24	8.5	3	182	196	18	6.1	500
	9 Jul 04	0.3	65	150	28	58	200	0.3	8.9	3	90	148	18	7.8	410
	19 Jan 04	0.2	54	120	25	110	160	0.22	6.8	3	97	261	18	5.8	490
	4 Aug 03	0.2	49	130	24	45	140	0.23	7.4	2	90	136	18	6.2	380
	2 Jan 03	0.2	54	140	28	53	150	0.22	7.5	2	90	135	18	5.1	340
ES4	5 Jul 06	<0.1	22	49	13	33	73	0.11	4.4	1	180	59	18	3.4	200
	3 Jan 06	0.1	24	55	12	23	72	0.1	3.8	1	180	128	18	3.5	350
	1 Aug 05	<0.1	25	49	13	28	81	0.12	3.5	1	181	140	18	4.9	290
	2 Feb 05	0.1	36	75	19	39	110	0.2	6.3	2	200	402	18	4.9	470
	9 Jul 04	0.1	24	52	12	23	75	0.1	4.1	1	90	145	18	2.5	310
	19 Jan 04	0.1	25	64	13	23	81	0.2	4.4	2	109	128	18	4.2	440
	4 Aug 03	0.1	32	58	19	34	95	0.23	6.1	1	93	162	18	6.5	420
	2 Jan 03	0.2	32	74	19	38	110	0.3	5.8	2	101	252	18	9	410
ES1	5 Jul 06	<0.1	19	26	13	25	68	0.11	3.6	1	180	46	18	5.4	190
	3 Jan 06	<0.1	20	28	12	22	61	0.08	4	1	180	91	18	2.2	320
	1 Aug 05	<0.1	19	30	12	48	63	0.09	4.1	1	180	56	18	6.7	250
	2 Feb 05	<0.1	13	18	9	18	42	0.06	3.7	0	180	51	18	6.7	260
	9 Jul 04	<0.1	23	36	13	22	73	0.1	5	1	90	126	18	3.6	250
	19 Jan 04	<0.1	17	25	12	21	55	0.08	4.2	1	141	391	18	4.5	230
	4 Aug 03	0.2	36	87	18	32	100	0.17	5.4	2	90	85	18	1.5	430
	2 Jan 03	<0.1	15	17	13	24	47	1	3.5	0	90	21	18	20	190
ES2	5 Jul 06	<0.1	26	20	19	28	79	0.07	6.3	0	180	33	18	2.9	210
	3 Jan 06	<0.1	41	38	27	50	120	0.12	6.7	1	180	96	18	13	590
	1 Aug 05	<0.1	30	32	19	39	89	0.1	6.5	1	181	93	18	67	380
	2 Feb 05	<0.1	29	26	20	35	88	0.09	6.5	0	196	190	18	4.3	540
	9 Jul 04	<0.1	26	19	16	21	64	<0.05	7.1	<0	90	137	18	4.7	250
	19 Jan 04	<0.1	38	42	25	44	110	0.14	5.6	1	107	108	18	9.4	530
	4 Aug 03	<0.1	20	16	14	21	71	0.06	5.5	0	90	67	18	4.5	350
	2 Jan 03	<0.1	26	22	20	28	56	0.06	4.9	0	90	49	18	9.1	270
Criteria	LCEL	1.5	80	65	40	75	200	0.5	12	1	550	1700	23	n/a	n/a
Criteria	UCEL	4	160	110	40	110	270	1	42	2	3160	9600	180	n/a	n/a

Notes: ^ one congener, naphthalene, was assumed as <60 µg/kg since no data were recorded.

Table 3.3 Sediment Quality in Junk Bay

Sampling Location	Sampling Depth (m)		Metals and Metalloid Content (mg/kg)									µg/kg			µg/L
Sampling Location	From	To	Cd	Cr	Cu	Ni	Pb	Zn	Hg	As	Ag	LMW PAHs	HMW PAHs	PCBs	TBT
VC13	0.57	0.90	0.2	24	36	12	44	160	0.2	4.8	0.3	<550	<1700	<23	<0.15
	0.90	1.90	0.2	29	29	16	50	160	0.6	5.5	0.4	<550	<1700	<23	<0.15
	1.90	2.90	0.1	26	6.2	20	17	55	0.2	3.6	<0.1	<550	<1700	<23	<0.15
	2.90	3.90	0.1	28	8.5	21	21	130	0.2	3.9	<0.1	<550	<1700	<23	<0.15
	6.17	6.90	0.1	25	7.4	18	22	81	0.1	3.7	<0.1	<550	<1700	<23	<0.15
	8.90	9.90	0.1	26	8.9	19	31	52	0.1	5.1	<0.1	<550	<1700	<23	<0.15
	12.00	12.70	0.2	20	7.6	14	28	170	0.1	7.9	<0.1	<550	<1700	<23	<0.15
VC5	0.12	0.90	0.2	39	92	17	42	90	0.2	4.8	0.7	<550	<1700	<23	<0.15
	0.90	1.90	<0.1	25	8.4	19	23	130	0.1	4.0	<0.1	<550	<1700	<23	<0.15
	1.90	2.90	0.1	24	7.0	18	19	170	0.1	4.0	<0.1	<550	<1700	<23	<0.15
	2.90	3.90	0.1	25	7.8	19	19	100	0.1	4.2	<0.1	<550	<1700	<23	<0.15
	6.10	6.90	0.2	25	19	16	27	90	0.2	3.9	0.2	<550	<1700	<23	<0.15
	8.90	9.90	0.1	27	8.6	20	27	70	0.1	3.9	<0.1	<550	<1700	<23	<0.15
	12.00	12.90	0.1	22	8.6	16	35	49	0.08	7.1	<0.1	<550	<1700	<23	<0.15
	14.90	15.96	0.2	20	8.2	14	43	49	0.08	8.3	<0.1	<550	<1700	<23	<0.15
VC18	0.90	1.00	<0.6	35	57	20	63	300	0.1	10	<1	NA	NA	NA	NA
	1.90	2.00	0.9	43	93	10	160	950	0.2	10	<1	NA	NA	NA	NA
	2.90	3.00	<0.6	130	7	71	20	39	<0.1	6	<1	NA	NA	NA	NA
	5.75	5.85	<0.6	42	9	24	20	71	<0.1	7	<1	NA	NA	NA	NA
	8.90	9.00	<0.6	32	9	20	24	63	<0.1	7	<1	NA	NA	NA	NA
	11.75	11.85	0.9	<10	<5	10	180	20	<0.1	13	<1	NA	NA	NA	NA
G1*	N/A	N/A	<0.6	26	42	10	90	590	0.2	11	<1	NA	NA	NA	NA
Criteria	LCEL		1.5	80	65	40	75	200	0.5	12	1	550	1700	23	0.15
Criteria	UCEL		4	160	110	40	110	270	1	42	2	3160	9600	180	0.15

Notes: * sampling depth at seabed

3.4.2.10 With reference to Table 3.3 and Figure 3.3, levels of lead, nickel and zinc are high at sampling stations “VC18” and “G1” at the northwest of Junk Bay, with this sediment at these stations classed under ETWB 34/2002 criteria as ‘Category H’.

3.4.2.11 Towards the middle of Junk Bay area, data from stations “VC13” and “VC5” – both to a depth of several metres – indicates the sediment to be uncontaminated except in surface layers where sediment is classed as ‘Category M’ due to marginal exceedance of the criteria for copper and mercury.

3.4.2.12 Following the Tier I desktop sediment quality review summarized in the prior sections, a Tier II sampling and chemical screening programme was devised. This involved sediment collection at three nearshore stations in Junk Bay / Tathong Channel (S1 – S3) in January 2007, and at four offshore stations located in SE waters in May 2007 when the offshore conditions were suitable for such operations.

3.4.2.13 With reference to Figure 3.3 it is apparent that this nearshore transmission cable-dredging zone coincides with nearshore sampling stations S1, S1-B and S2.

3.4.2.14 Table 3.5 presents the Tier II classification of marine sediment at these three nearshore in accordance with the ETWB 34/2002 criteria. Sub-samples ‘S1-1’ and ‘S2-1’ are categorized as Type 2 sediment as levels of zinc exceed the UCEL, although in accordance with Clause 2(d) of ETWB 34/2002 Appendix B there is no requirement for Tier III biological screening as contamination levels are <10 times the LCEL.

3.4.2.15 In accordance with Appendix C of ETWB 34/2002, the upper 0.9m of sediment at stations S1 and S2 will thus require Type 2 confined marine disposal. As per the Dumping at Sea Ordinance (Cap. 466), ‘Category H’ sediment must be carefully dredged and transported, and effectively isolated from the environment upon final disposal.

3.4.2.16 A conservative estimate of the potential volume of each type of sediment to be disposed is summarized in Table 3.4. This estimate takes into account the Tier II chemical screening results, which indicate that only surface sediment (up to 1m) is contaminated, and is based on a trapezoidal trench of nominal 3m depth.

Table 3.4 Preliminary Estimated Volume of Sediment & Disposal Option (m³)

Disposal Option	Estimated Volume of Sediment
Type 1 – Open Sea Disposal	70,000
Type 2 – Comfined Marine Disposal	65,000
Total	135,000

3.4.2.17 Before the dredging operation commences, it is proposed that surface grab samples be collected in a focussed investigation area in advance of any dredging works in order to comply with the specific requirements of the Dumping at Sea Ordinance. This approach will enable the volume of contaminated sediment requiring confined marine disposal to be more accurately quantified.

3.4.2.18 It is anticipated that surface sediment from the potential marine dredging in the vicinity of stations S1 and S2 would be disposed of at East Sha Chau, being the designated site for confined marine disposal. The disposal method shall be subject to the agreement of the Marine Fill Committee (MFC) of CEDD in due course.

3.4.2.19 The fate and magnitude of dredged sediment impacts is reviewed within the Water Quality Assessment, Section 4.

Table 3.5 Chemical Screening Results for Nearshore Stations S1 - S3

Parameter		Ag	As	Cd	Cr	Cu	Ni	Pb	Zn	Hg	Total PCB	L.M.W.	H.M.W.	TBT-soluble	Category
Unit (dry wt.)		mg/kg	mg/kg	mg/kg	mg/kg	mg/kg	mg/kg	mg/kg	mg/kg	mg/kg	µg/kg	µg/kg	µg/kg	µg TBT/L
Reporting Limits	Depth	0.1	1	0.1	1	1	1	1	1	0.05	2	550	1700	0.005
S1-1	0.0 to 0.9	0.5	5	0.6	11	22	5	198	426	0.13	8	<550	<1700	-	H
S1-2	1.0 to 1.9	<0.1	2	<0.1	9	3	4	10	20	0.03	<3	<550	<1700	-	L
S1B-1	0.0 to 0.9	0.3	4	0.2	15	14	8	29	157	0.06	<1	<550	<1700	0.021	L
S1B-2	1.0 to 1.9	0.2	6	0.2	37	26	10	30	65	0.23	<1	<550	<1700	<0.012	L
S1B-3	2.0 to 2.9	<0.1	4	0.1	21	5	14	13	49	0.02	<1	<550	<1700	-	L
S1B-4	3.0 to 3.9	<0.1	5	<0.1	25	6	17	15	58	0.03	<1	<550	<1700	-	L
S2-1	0.0 to 0.9	0.2	6	0.3	41	18	22	37	352	0.06	54	<550	<1700	-	H
S2-2	1.0 to 1.9	0.1	6	0.1	29	7	20	17	67	0.02	<1	<550	<1700	-	L
S2-3	2.0 to 2.9	0.1	6	0.1	29	7	19	16	62	0.03	<1	<550	<1700	-	L
S2-4	3.0 to 3.9	0.2	5	0.1	29	8	19	19	60	0.05	<1	<550	<1700	-	L
S3-1	0.0 to 0.9	0.4	8	0.2	38	42	20	42	101	0.37	<1	<550	<1700	-	L
S3-2	1.0 to 1.9	0.1	8	<0.1	25	11	17	32	69	0.17	<1	<550	<1700	-	L
S3-3	2.0 to 2.9	0.1	6	0.2	29	7	20	16	66	0.06	<1	<550	<1700	-	L
S3-4	3.0 to 3.9	<0.1	5	0.1	30	7	22	16	69	0.04	<1	<550	<1700	-	L
Criteria	LCEL	1	12	1.5	80	65	40	75	200	0.5	23	550	1700	0.15	-
Criteria	UCEL	2	42	4	160	110	40	110	270	1	180	3160	9600	0.15	-

Notes: Sampling location S1 was relocated to S1B after vibrocore failure due to loose abundant sediment

L.M.W.: Low Molecular Weight

H.M.W.: High Molecular Weight

3.4.3 Chemical Waste

3.4.3.1 Chemical waste, as defined under the Waste Disposal (Chemical Waste) (General) Regulation, includes any substance being scrap material or unwanted substances specified under Schedule 1 of the Regulation.

3.4.3.2 Chemical waste associated with Project construction and maintenance activities may include the following:

· Paint from turbine and blade coating

· Chemical solvents used for cleaning parts / materials

· Mineral oils for construction plant maintenance

· Mineral and hydraulic oils for turbines and transformer

· Fuel oil for operation of marine construction vessels

3.4.3.3 Such wastes may pose environmental, health and safety hazards if not stored and disposed of in an appropriate manner. Potential hazards may include:

· Toxic effects to workers

· Adverse impacts on water quality / marine biota from spills

· Fire hazards.

3.4.3.4 All individual Project components including foundation structures, cables, turbine towers, gearboxes and blades, and the transformer platform and station will be constructed and prefabricated in dedicated factory environments by suppliers. There will only be limited local assembly of these components (subject to the detailed design and programming).

3.4.3.5 Sub-section 2.1 refers to the oils and fluids that shall be contained within each turbine (mainly within the nacelle) and inside the offshore transformer, and it is noted that standard design measures for these components include full provision for the containment of leaks and spills.

3.4.3.6 Overall it is anticipated that the overall quantity of chemical wastes shall be small. The actual quantity of chemical waste generated shall be quantified in the Waste Management Plan to be prepared by the Contractor.

3.4.3.7 Chemical wastes associated with construction and maintenance activities may be disposed at the Chemical Waste Treatment Centre (CWTC) at Tsing Yi. The storage, handling, transportation and disposal of all chemical wastes shall be in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Waste published by the EPD. Other relevant control measures for chemical waste are referred in sub-section 3.5.

3.4.4 Sewage

3.4.4.1 Sewage generated by the construction workforce shall be properly managed to avoid nuisance (odour, pests) and adverse environmental and health impacts. It is anticipated that a workforce of approximately 300 shall be employed at the peak of construction (200 at sea, 100 on land). Based on an indicative per capita sewage generation rate of 0.15 m³ per day (DSD, 1995), it is estimated that no more than 45m³ of sewage may be generated per day during peak construction. A smaller volume of sewage shall be associated with routine maintenance activities.

3.4.4.2 Onshore assembly shall be in large-scale construction yard with facilities connected to the sewerage mains, while offshore sewerage shall be handled via appropriate sewerage handling facilities (e.g. sewage holding tank) aboard marine vessels. Accordingly, no adverse environmental impacts are envisaged.

3.4.5 General Refuse

3.4.5.1 General refuse generated by the construction and maintenance workforce requiring appropriate handling and disposal shall mainly comprise food waste and packaging, and potentially metal drinks cans and waste paper.

3.4.5.2 Potential impacts associated with improper handling and disposal may include odour, windblown litter and water quality impacts. Based on a peak construction workforce of approximately 300 / day and a per capita general refuse generation rate of 0.97 kg per day (EPD, 2007), it is estimated that approximately 290 kg of general refuse may be generated per day. A smaller quantity of general refuse shall be associated with routine maintenance activities.

3.4.5.3 Recyclable materials such as paper, plastic bottles and metal cans shall be separated at source for recycling. Non-recyclable general refuse shall be kept fully contained and regularly disposed by reputable waste collectors at a designated disposal outlet.

3.4.5.4 Provided the best practice measures, as recommended in sub-section 3.5, are implemented, adverse impacts from the storage, handling, transport and disposal of general refuse are not anticipated.

3.5 Mitigation of Adverse Impacts

3.5.1.1 There are no major waste management issues associated with Project construction and maintenance, and hence no impact mitigation measures are required. However, good site practice is encouraged and the following measures are recommended during Project construction and maintenance to avoid potential impacts associated with handling, collection and disposal of waste arising from the construction phase of the Project.

3.5.1.2 The Contractors shall incorporate these recommendations into a Waste Management Plan for the construction works. It is also reminded that the Contractor shall comply with all relevant statutory requirements and guidelines and their updated versions that may be issued during the course of the Project.

3.5.1.3 It is also the Contractor's responsibility to ensure that only reputable or licensed waste collectors are used and that appropriate measures to minimise adverse impacts are employed. In addition, the Contractor shall ensure that all the necessary waste disposal permits are obtained throughout the construction phase.

3.5.2 Dredged Marine Sediment

3.5.2.1 According to the requirements stipulated in ETWB 34/2002, the dredged sediment shall only be disposed at designated sites allocated by MFC based on the findings of sediment quality tests. A marine disposal license shall be obtained from EPD prior to the commencement of marine dredging works.

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

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

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

· 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.

3.5.2.3 More specific measures for the control of dredged marine sediment are presented in Section 4, Water Quality, informed by the numerical modelling exercise.

3.5.3 Chemical Waste

3.5.3.1 The Contractor shall 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.

3.5.3.2 Containers used for storage of chemical wastes should:

· Be suited to the substance they are holding, resistant to corrosion, maintained in a good condition, and securely closed;

· Have a capacity of less than 450 L unless the specifications have been approved by the EPD; and

· Display a label in English and Chinese in accordance with Schedule 2 of the Regulations.

3.5.3.3 The storage area for chemical wastes shall:

· Be clearly labelled and be used only for the storage of chemical waste;

· Be enclosed on a minimum of 3 sides;

· Have an impermeable floor, 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 greater;

· Provide adequate ventilation;

· Be covered to prevent rainfall permeation (water collected within the bund must be tested and disposed of as chemical waste, if necessary); and

· Be arranged so that incompatible materials are separated appropriately.

3.5.3.4 Disposal of chemical waste shall be:

· Via a licensed waste collector; and

· To a facility licensed to receive chemical waste, such as the Chemical Waste Treatment Facility which also offers a chemical waste collection service and can supply the necessary storage containers.

3.5.4 Sewage

3.5.4.1 An adequate number of portable toilets, if necessary, should be provided for the construction and maintenance workforce is sufficient are not provided at any onshore assembly area. Portable toilets shall be maintained in a state that will not deter the workers from using them. Night soil shall be regularly collected by a licensed collector for disposal at a Sewage Treatment Works.

3.5.5 General Refuse

3.5.5.1 General refuse shall be stored in fully contained units separate from chemical wastes. The general refuse storage area shall be regularly maintained by a reputable waste collector, with waste to be disposed at a designated refuse transfer station.

3.5.5.2 The Contractor shall be responsible for identifying which materials can be recycled/reused, whether on site or off site. In the event of the latter, the Contractor shall make arrangements for the collection of the recyclable materials. Separate labelled bins for their deposit shall be provided if feasible.

3.5.5.3 Further to the issue of ETWBTC (Works) No. 6/2002A, Enhanced Specification for Site Cleanliness and Tidiness, the Contractor is required to maintain a clean and hygienic site throughout the Project.

3.6 Assessment of Residual Impacts

3.6.1.1 There are no adverse waste impacts or hence residual impacts associated with Project construction or maintenance.

3.7 Environmental Monitoring and Audit

3.7.1 Construction Phase

3.7.1.1 The assessment has concluded that under proper handling, storage, collection, transportation and disposal of waste materials generated during construction of the Project will not give rise to any significant impacts.

3.7.1.2 While no specific environmental monitoring and audit (EM&A) requirements have been identified, it is recommended during construction that the Contractor provides a designated manager to conduct appropriate inspections and to supervise the implementation of waste management control measures suggested in sub-section 3.5.

3.7.1.3 An appropriate audit programme shall be scheduled in the WMP to be prepared by the Contractor, and a summary of the site audits shall be presented in the EM&A reports as required by the EM&A Manual.

3.7.2 Operational Phase

3.7.2.1 No adverse environmental impact will arise with the implementation of good waste management practices and accordingly no EM&A programme is required.

3.8 Conclusion

3.8.1.1 The key potential impacts during the construction phase are related to management of dredged sediments, with approximately 135,000 m³ of marine sediment shall potentially be dredged. Based on completed sediment analysis, a preliminary estimate is that 65,000m³ may require Type 2 confined marine disposal.

3.8.1.2 The final disposal site shall be determined by the Marine Fill Committee of CEDD. A dumping license shall be obtained from EPD prior to the commencement of dredging works and with reference to the results of additional sediment quality sampling and analysis conducted to satisfy the requirements of the Dumping at Sea Ordinance.

3.8.1.3 Other waste types associated with Project development include chemical wastes, sewage and general refuse. No significant environmental impacts from the handling and disposal of these waste types are anticipated, subject to the full implementation of the relevant waste management standards and guidelines and best practices referred in sub-section 3.5.

3.9 References

3.9.1.1 DSD, 1995. Sewerage Manual (Part 1): Key Planning Issues and Gravity Collection System. Drainage Services Department, HKSAR.

3.9.1.2 EPD (2003-2006). Routine Marine Sediment Monitoring Data. Environmental Protection Department, HKSAR.

3.9.1.3 Maunsell (2005). Tseung Kwan O Further Development EIA Study Report.