4. Waste Management Impact Assessment

4.1 Introduction

This section identifies the types of wastes arising as a result of the construction and operation of the Project in accordance with the detailed requirements outlined in Condition 3.4.6 of the EIA Study Brief. The major waste will be dredged marine sediment from the Kwai Tsing Container Basin (KTCB) and portions of Western Fairway and Northern Fairway, as well as construction and demolition (C&D) materials resulting from the modification and dismantling works for Kwai Chung and Tsing Yi submarine sewage outfalls. Mitigation measures and good site practices, including waste handling, collection, transportation and disposal are recommended with reference to the applicable waste legislation and guidelines.

This section presents the types of wastes arising as a result of the construction and operation of the Project and is structured as follows:

Section 4.2: Provides discussions on existing environmental legislation;

Section 4.3: Describes the assessment methodology adopted for this EIA;

Section 4.4: Provides discussions on the identification and evaluation of associated environmental impacts of this Project;

Section 4.5: Proposes potential mitigation measures to address the identified impacts;

Section 4.6: Evaluates the residual impacts;

Section 4.7: Proposes appropriate environmental monitoring and auditing programme; and

Section 4.8: Summarises the key findings of this section.

Assessments have been conducted in accordance with the requirements of the Study Brief and Annexes 7 and 15 of the Technical Memorandum on the Environmental Impact Assessment Process. The environmental impacts associated with the waste arising from marine dredged sediment, construction and demolition (C&D) materials, general refuse; and chemical waste have been assessed and their impacts due to the project works have been predicted. Based on the assessment, the marine dredged sediment was classified in accordance with their contamination level and their disposal options were identified as Type 1 (Open Sea Disposal) and Type 2 (Confined Marine Disposal) in certain parts of the Project Area. Details of which are further elaborated in the following subsections.

Appropriate mitigation measures have been recommended for the handling, transportation and disposal of the identified wastes to minimise the potential adverse impacts.

4.2 Environmental Legislation

The criteria and guidelines for assessing waste management implications are outlined in Annex 7 and Annex 15 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), respectively.

The following legislation relate to the handling, treatment and disposal of wastes in the Hong Kong SAR and have been used in assessing the potential waste impacts:

¡ Waste Disposal Ordinance (Cap. 354);

¡ Waste Disposal (Chemical Waste) (General) Regulation (Cap. 354);

¡ Public Health and Municipal Services Ordinance (Cap. 132) - Public Cleansing and Prevention of Nuisances Regulation; and

¡ Dumping at Sea Ordinance (Cap. 466).

4.2.1 Waste Management

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.

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.

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

4.2.2 Construction and Demolition (C&D) Materials

The current policy related to the dumping 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.

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.

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; and (ii) 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 exempted from the C&DMMP. 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 Waste Management Plan (WMP) has become part of the EMP.

4.2.3 Dredged Marine Sediment

ETWB TCW No. 34/2002, “Management of Dredged/Excavated Sediment” set out the procedures for seeking approval to dredge/excavate sediment and the management framework for marine disposal of such sediment. Dredged marine sediment arising from the Project will be managed in accordance with the requirements of ETWB TCW No. 34/2002.

In accordance with the Dumping at Sea Ordinance, application for dumping permits from EPD is required for marine disposal of dredged materials.

4.3 Assessment Methodology

4.3.1 General

In accordance with Condition 3.4.6.1 of the EIA Study Brief, the criteria for evaluating and assessing the waste management implications will follow Annexes 7 and 15 of the EIAO-TM and the assessment covered the scope outlined in Condition 3.4.6.2 (i) and (ii) of the EIA Study Brief, which includes the following:

Analysis of Activities and Waste Generation

¡ Identify the quantity, quality and timing of waste arising as a result of the construction and operation activities of the Project, and based on the sequence and duration of these activities to evaluate the potential environmental impacts that may result from these wastes.

Proposal for Waste Management

¡ 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 fully evaluated.

¡ Estimation of the types and quantities of the wastes required to be disposal of shall be described in detail.

¡ The transportation routings and the frequency of the vessels involved in the management of solid waste.

¡ Assessment of potential impacts from the management of solid waste with respect to potential hazards, air and odour emissions, noise, wastewater discharges and public transport.

4.3.2 Marine Site Investigation

As identified in Section 2.1, the purpose of the Project is to dredge the seabed of Kwai Tsing Container Basin, as well as portions of Northern Fairway and Western Fairway to achieve the seabed level of at least -17 mCD in order to provide sufficient depth of container basin and approach channel to Kwai Tsing Container Port (KTCP) for the safe navigation of the Ultra Large Container Ships (ULCS). To achieve the enhanced navigation depth, CEDD intends to dredge the seabed concerned to -17.5mCD. This is estimated to generate up to 4.4 million cubic meters of material to be disposed of over a period of about 24 months. In order to determine the quality of the material and thus the disposal arrangements, an assessment of the existing data was carried out followed by a proposed site investigation for the purpose of quantifying the nature of materials.

The nearest EPD sediment monitoring station from the proposed dredging location is VS9. The results of bottom sediment testing conducted between 2002 to 2006 indicated that a number of heavy metals such as Lead, Nickel, Silver and Zinc exceeded the Lower Chemical Exceedence Limits while Copper exceeded the Upper Chemical Exceedence Limit as per ETWB TCW No. 34/2002 “Management of Dredged/Excavated Sediment”. Preliminary review on the geological information at the boundary of dredging area was also carried out. Drillhole records showed that material with marine deposit was present at seabed levels in the range of -15.5 mCD and -17.5 mCD.

Based on the results of the previous studies discussed above, the dredged sediment from the Project could be contaminated with heavy metals. In accordance with the Condition 3.4.6.2 (iii) of the EIA Study Brief, a Sediment Sampling and Testing Plan (SSTP) was prepared and submitted to EPD for approval, which specified: the ranges of parameters to be analyzed; the number, type and methods of sampling; sample preservation; chemical and biological laboratory test method to be used for dredged sediment sampling and testing. The SSTP is attached in Appendix 4.1 of this report.

Marine site investigation works of the Project were carried out in November and December 2009. Drillhole records are presented in Appendix 4.2. The records indicated that the material consist mainly of marine deposits.

Laboratory testing of contaminants was included in the marine site investigation works to determine the level of contamination in the marine sediments at the existing seabed. The works included sampling at 48 locations at KTCB and portions of Western Fairway and Northern Fairway as detailed in Table 4.1. Locations of the grab and vibrocore sampling points are presented in Figures 4.1 and 4.2

Table 4.1: Vibrocore / Grab Sampling Locations and Thickness of Sediment Required Dredging

Sample No.	Easting	Northing	Existing Seabed Level (mCD)	Required Seabed Level (mCD)	Thickness of Sediment Required Dredging	Sampling Method
S1-1	829751.50	823002.60	-16.596	-17.5	0.904	Vibrocore
S2	830322.60	823158.10	-15.696	-17.5	1.804	Vibrocore
S3	829844.50	822694.30	-15.696	-17.5	1.804	Vibrocore
S4	830412.90	822870.90	-15.896	-17.5	1.604	Vibrocore
S5-2	829912.60	822376.50	-16.896	-17.5	0.604	Vibrocore
S6	830501.40	822584.50	-15.696	-17.5	1.804	Vibrocore
S7	830020.40	822122.30	-15.596	-17.5	1.904	Vibrocore
S8	830608.90	822303.60	-16.096	-17.5	1.404	Vibrocore
S9	830109.30	821837.90	-16.796	-17.5	0.704	Vibrocore
S10	830684.50	822012.20	-15.796	-17.5	1.704	Vibrocore
S11	830204.20	821545.10	-16.896	-17.5	0.604	Vibrocore
S12	830774.10	821730.40	-15.796	-17.5	1.704	Vibrocore
S14	830483.90	821322.20	-17.196	-17.5	0.304	Grab
S15	830859.80	821442.30	-15.896	-17.5	1.604	Vibrocore
S16*	830574.12	821036.08	-17.982	-17.5	NA	-
S17	830945.80	821150.50	-16.996	-17.5	0.504	Vibrocore
S19	831006.10	820989.20	-15.196	-17.5	2.304	Vibrocore
S18	830759.70	820778.00	-17.396	-17.5	0.104	Grab
S13	830191.50	821219.90	-17.296	-17.5	0.204	Grab
S21	830544.20	820516.70	-15.896	-17.5	1.604	Vibrocore
D174	830310.60	820531.50	-17.296	-17.5	0.204	Vibrocore
D176*	830032.99	821050.77	-18.066	-17.5	NA	-
D196	829815.90	820796.00	-15.896	-17.5	1.604	Vibrocore
D202	829981.70	820245.80	-16.496	-17.5	1.004	Vibrocore
D214	829800.60	820169.70	-15.996	-17.5	1.504	Vibrocore
D221	829441.40	820630.30	-16.596	-17.5	0.904	Vibrocore
D234	829293.50	820427.40	-16.896	-17.5	0.604	Vibrocore
D238	829419.60	820041.60	-15.996	-17.5	1.504	Vibrocore
S30	829215.40	819801.60	-15.496	-17.5	2.004	Vibrocore
S29	828919.50	820298.10	-17.396	-17.5	0.104	Grab
D272	828736.50	820213.20	-17.196	-17.5	0.304	Grab
S32	828910.10	819654.10	-15.996	-17.5	1.504	Vibrocore
D298	828407.20	819932.80	-16.596	-17.5	0.904	Vibrocore
S34	828581.30	819381.40	-15.496	-17.5	2.004	Vibrocore
S35	828215.50	819875.50	-16.996	-17.5	0.504	Vibrocore
D320	828454.40	819128.20	-15.896	-17.5	1.604	Vibrocore
D330	827850.90	817204.30	-16.896	-17.5	0.604	Vibrocore
D337	827988.70	816837.30	-16.496	-17.5	1.004	Vibrocore
S40	828138.20	816465.50	-16.896	-17.5	0.604	Vibrocore
D355	828276.30	816086.40	-17.396	-17.5	0.104	Vibrocore
D362	828427.20	815712.50	-16.896	-17.5	0.604	Vibrocore
S44	828564.80	815345.90	-16.596	-17.5	0.904	Vibrocore
D374	828716.40	814970.50	-16.896	-17.5	0.604	Vibrocore
S47	828840.20	814648.30	-16.596	-17.5	0.904	Vibrocore
D378	828953.60	814367.80	-16.596	-17.5	0.904	Vibrocore
D381	829105.70	814056.50	-16.796	-17.5	0.704	Vibrocore
S50	829282.80	813690.60	-16.896	-17.5	0.604	Vibrocore
D386	829454.30	813327.60	-17.396	-17.5	0.104	Vibrocore
S1-2^#	829738.50	822949.10	-17.193	-17.5	0.307	Vibrocore
S1-3^#	829783.40	822962.60	-17.913	-17.5	NA	-
D1-2^#	829831.10	822977.60	-17.326	-17.5	0.174	Grab
D6-1^#	829750.80	822899.90	-17.122	-17.5	0.378	Grab
D7-2^#	829895.70	822949.40	-16.096	-17.5	1.404	Grab
D25-4^#	829903.70	822581.10	-17.196	-17.5	0.304	Grab
D26-1^#	829937.90	822642.20	-16.389	-17.5	1.111	Vibrocore
D26-2^#	829951.40	822596.10	-16.390	-17.5	1.110	Grab
D39-1^#	829996.50	822453.10	-17.469	-17.5	0.031	Grab
D39-2^#	830011.50	822405.40	-16.726	-17.5	0.774	Grab
D45-1^#	830026.50	822357.70	-16.808	-17.5	0.692	Grab
Ref. Sediment	-	-	-	-	-	-
* Sampling is not required as the depth of seabed is deeper than -17.5mCD. ^# In addition to the locations of the sampling points proposed in the approved SSTP, S1-2,S1-3,D1-2,D1-3,D6-1 ,D7-2,D25-3,D25-4,D26-1,D26-2,D39-1,D39-2 and D45-1 around the outfalls are provided as supplementary information.

4.3.2.1 Chemical Testing

Sample Arrangement

Tier II chemical screening was carried out to determine whether the sediment is suitable for open sea disposal without further testing in accordance with the requirements of ETWB TCW No. 34/2002. Sediment samples collected for chemical testing are presented in Table 4.2.

Table 4.2: Sample Arrangement for Chemical Testing

Sample No.	Easting	Northing	Sample taken at depth (m)	No. of Sub- Sample(s)
S1-1	829751.50	823002.60	0m~0.9m & 0.9m~1.9m	2
S2	830322.60	823158.10	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S3	829844.50	822694.30	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S4	830412.90	822870.90	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	2
S5-2	829948.78	822438.03	0m~0.9m & 0.9m~1.9m	2
S6	830501.40	822584.50	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S7	830020.40	822122.30	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S8	830608.90	822303.60	0m~0.9m & 0.9m~1.9m	2
S9	830109.30	821837.90	0m~0.9m & 0.9m~1.9m	2
S10	830684.50	822012.20	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S11	830204.20	821545.10	0m~0.9m & 0.9m~1.9m	2
S12	830774.10	821730.40	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S14	830483.90	821322.20	0m~0.9m	1
S15	830859.80	821442.30	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S16*	830574.12	821036.08	NA	-
S17	830945.80	821150.50	0m~0.9m & 0.9m~1.9m	2
S19	831006.10	820989.20	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S18	830759.70	820778.00	0m~0.9m	1
S13	830191.50	821219.90	0m~0.9m	1
S21	830544.20	820516.70	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D174	830310.60	820531.50	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D176*	830032.99	821050.77	NA	-
D196	829815.90	820796.00	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D202	829987.70	820245.80	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D214	829800.60	820169.70	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D221	829441.40	820630.30	0m~0.9m & 0.9m~1.9m	2
D234	829293.50	820427.40	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D238	829419.60	820041.60	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S30	829215.40	819801.60	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S29	828919.50	820298.10	0m~0.9m	1
D272	818736.50	820213.20	0m~0.9m	1
S32	828910.10	819654.10	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D298	828407.20	819932.80	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S34	828581.30	819381.40	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S35	828215.50	819875.50	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D320	828454.40	819128.20	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D330	827850.90	817204.30	0m~0.9m & 0.9m~1.9m	2
D337	827988.70	816837.30	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S40	828138.20	816465.50	0m~0.9m & 0.9m~1.9m	2
D355	828276.30	816086.40	0m~0.9m & 0.9m~1.9m	2
D362	828427.20	815712.50	0m~0.9m & 0.9m~1.9m	2
S44	828564.80	815345.90	0m~0.9m & 0.9m~1.9m	2
D374	828716.40	814970.50	0m~0.9m & 0.9m~1.9m	2
S47	828840.20	814648.30	0m~0.9m & 0.9m~1.9m	2
D378	828953.60	814367.80	0m~0.9m & 0.9m~1.9m	2
D381	829105.70	814056.50	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
S50	829282.80	813690.60	0m~0.9m & 0.9m~1.9m & 1.9m~2.9m	3
D386	829454.30	813327.60	0m~0.9m & 0.9m~1.9m	2
S1-2	829738.50	822949.10	0m~0.9m & 0.9m~1.9m	2
S1-3	829783.40	822962.60	0m~0.9m	1
D1-2	829831.10	822977.60	0m~0.9m	1
D6-1	829750.80	822899.90	0m~0.9m	1
D7-2	829895.70	822949.40	0m~0.9m & 0.9m~1.9m	2
D25-4	829903.70	822581.10	0m~0.9m	1
D26-1	829937.90	822642.20	0m~0.9m & 0.9m~1.9m	2
D26-2	829951.40	822596.10	0m~0.9m	1
D39-1	829996.50	822453.10	0m~0.9m	1
D39-2	830011.50	822405.40	0m~0.9m	1
D45-1	830026.50	822357.70	0m~0.9m	1
Ref. Sediment	-	-	-	-

* Sampling is not required as the depth of seabed is deeper than -17.5mCD.

Sample Preparation, Determination Method and Reporting Limits

Details of the sample preparation, determination methods and reporting limits referred in the approved SSTP are attached as Appendix 4.1 of this Report.

4.3.2.2 Chemical Screening

The marine sediment quality analysis results of chemical screening from the marine site investigation works are included as Appendix 4.3, and are compared with the sediment quality criteria for the classification of sediment, which are presented in Table 4.3.

The sediment chemical testing results presented in Table 4.4 indicated that Category L, M and H sediments were identified. Sediment samples required to proceed to Tier III biological screening and the ancillary tests results are presented in Table 4.5.

Chlorinated pesticides (including Aldrin, Alpha-BHC,Beta BHC & Gamma BHC, Delta-BHC, Heptachlor, Heptachlor epoxide, Endosulfan 1, Endosulfan sulphate, p, p’-DDT, p, p’-DDD and p, p’-DDE) were measured in sediment samples. The laboratory results showed that all the samples are below the detection limit which means pesticides were not detected in any of the sediment.

Table 4.3: Contaminant Levels of Samples and Their Categories

Analyte Description		Silver	Arsenic	Cadmium	Chromium	Copper	Nickel	Lead	Zinc	Mercury	Total PCB	Low M.Wt PAHs	High M.Wt PAHs	Tributyltin – Soluble	Category^#	Bio. Test
Unit (In dry Wt basis)		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
Sample ID
S1-1	0-0.9M	<0.1	1	<0.2	15	6	11	14	35	<0.05	<3	<550	<1700	IS	L	No
S1-1	0.9-1.9M	<0.1	2	<0.2	23	8	16	19	54	<0.05	<3	<550	<1700	IS	L	No
S2	0-0.9M	4.4	11	0.6	72	161	38	51	225	0.18	<3	<550	<1700	19	H	No*
S2	0.9-1.9M	6	11	0.7	80	188	42	52	262	0.23	<3	<550	<1700	<15	H	No*
S2	1.9-2.9M	0.1	4	<0.2	23	10	7	28	27	<0.05	<3	<550	<1700	IS	L	No
S3	0-0.9M	0.1	2	<0.2	10	5	5	10	24	<0.05	<3	<550	<1700	IS	L	No
S3	0.9-1.9M	<0.1	2	<0.2	17	6	10	13	41	<0.05	<3	<550	<1700	IS	L	No
S3	1.9-2.9M	<0.1	3	<0.2	19	6	12	16	47	<0.05	<3	<550	<1700	IS	L	No
S4	0-0.9M	3	9	0.5	68	135	34	52	196	0.28	<3	<550	<1700	IS	H	No*
S4	0.9-1.9M	0.7	8	<0.2	43	40	29	41	104	0.17	<3	<550	<1700	IS	L	No
S4	1.9-2.9M	0.2	6	<0.2	22	9	11	20	47	<0.05	<3	<550	<1700	IS	L	No
S5-2	0-0.9M	1.1	12	1.3	68	62	30	83	224	0.95	<3	<550	<1700	IS	M	Yes
S5-2	0.9-1.9M	0.1	13	<0.2	48	16	28	34	102	<0.05	<3	<550	<1700	IS	M	Yes
S6	0-0.9M	1.6	7	0.3	45	60	25	32	117	0.10	<3	<550	<1700	IS	M	Yes
S6	0.9-1.9M	1.3	8	0.2	46	53	26	32	120	0.08	<3	<550	<1700	IS	M	Yes
S6	1.9-2.9M	1.1	8	0.3	46	68	25	36	119	0.17	<3	<550	<1700	IS	M	Yes
S7	0-0.9M	<0.1	2	<0.2	15	5	8	11	36	<0.05	<3	<550	<1700	IS	L	No
S7	0.9-1.9M	<0.1	3	<0.2	14	4	8	11	33	<0.05	<3	<550	<1700	IS	L	No
S7	1.9-2.9M	<0.1	3	<0.2	15	5	9	12	36	<0.05	<3	<550	<1700	IS	L	No
S8	0-0.9M	0.1	9	<0.2	42	14	28	33	83	<0.05	<3	<550	<1700	IS	L	No
S8	0.9-1.9M	<0.1	13	<0.2	37	12	24	33	73	<0.05	<3	<550	<1700	IS	M	Yes
S9	0-0.9M	1	10	0.3	46	43	25	44	124	0.35	<3	<550	<1700	IS	M	Yes
S9	0.9-1.9M	0.1	14	<0.2	46	16	26	37	98	<0.05	<3	<550	<1700	IS	M	Yes
S10	0-0.9M	3.2	9	0.4	66	167	34	46	196	0.16	<3	<550	<1700	IS	H	No*
S10	0.9-1.9M	0.4	11	<0.2	46	24	30	36	96	0.06	<3	<550	<1700	IS	L	No
S10	1.9-2.9M	0.1	12	<0.2	44	16	30	38	92	<0.05	<3	<550	<1700	IS	L	No
S11	0-0.9M	0.1	13	<0.2	43	15	28	35	96	<0.05	<3	<550	<1700	IS	M	Yes
S11	0.9-1.9M	0.1	14	<0.2	44	16	27	39	97	<0.05	<3	<550	<1700	IS	M	Yes
S12	0-0.9M	<0.1	8	<0.2	41	13	28	30	80	<0.05	<3	<550	<1700	IS	L	No
S12	0.9-1.9M	0.1	13	<0.2	50	17	32	36	97	<0.05	<3	<550	<1700	IS	M	Yes
S12	1.9-2.9M	0.1	11	<0.2	50	18	33	39	102	<0.05	<3	<550	<1700	IS	L	No
S13		5	9	0.7	71	164	34	42	149	0.19	<3	<550	<1700	IS	H	No*
S14		0.1	7	<0.2	20	8	13	14	46	<0.05	<3	<550	<1700	IS	L	NO
S15	0-0.9M	1.1	6	0.2	47	50	28	37	111	0.10	<3	<550	<1700	IS	M	Yes
S15	0.9-1.9M	0.1	10	<0.2	47	17	31	37	95	0.05	<3	<550	<1700	IS	L	No
S15	1.9-2.9M	0.1	11	<0.2	48	17	32	37	96	<0.05	<3	<550	<1700	IS	L	No
S17	0-0.9M	<0.1	5	<0.2	42	12	28	27	84	<0.05	<3	<550	<1700	IS	L	No
S17	0.9-1.9M	<0.1	4	<0.2	41	12	29	29	83	<0.05	<3	<550	<1700	IS	L	No
S18		0.4	9	<0.2	37	19	25	24	88	0.06	<3	<550	<1700	IS	L	No
S19	0-0.9M	<0.1	7	<0.2	45	13	30	32	86	<0.05	<3	<550	<1700	IS	L	No
S19	0.9-1.9M	0.1	10	<0.2	44	15	29	32	85	<0.05	<3	<550	<1700	IS	L	No
S19	1.9-2.9M	0.1	10	<0.2	44	16	29	37	92	<0.05	<3	<550	<1700	IS	L	No
S21	0-0.9M	0.1	10	<0.2	46	16	31	33	90	<0.05	<3	<550	<1700	IS	L	No
S21	0.9-1.9M	0.1	13	<0.2	46	16	30	34	100	<0.05	<3	<550	<1700	IS	M	Yes
S21	1.9-2.9M	0.4	8	<0.2	42	28	26	42	118	0.40	<3	<550	<1700	IS	L	No
D174	0-0.9M	0.1	11	<0.2	41	13	27	28	84	<0.05	<3	<550	<1700	<15	L	No
D174	0.9-1.9M	0.1	11	<0.2	43	15	28	32	92	<0.05	<3	<550	<1700	IS	L	No
D174	1.9-2.9M	0.1	14	<0.2	42	15	28	34	93	<0.05	<3	<550	<1700	IS	M	Yes
D196	0-0.9M	0.6	9	<0.2	33	30	21	63	132	0.78	<3	<550	<1700	IS	M	Yes
D196	0.9-1.9M	0.1	15	<0.2	39	16	25	35	91	<0.05	<3	<550	<1700	IS	M	Yes
D196	1.9-2.9M	0.1	16	<0.2	38	16	24	35	89	<0.05	<3	<550	<1700	IS	M	Yes
D202	0-0.9M	<0.1	5	<0.2	39	12	27	23	75	<0.05	<3	<550	<1700	IS	L	No
D202	0.9-1.9M	<0.1	9	<0.2	40	13	27	25	75	<0.05	<3	<550	<1700	IS	L	No
D202	1.9-2.9M	0.1	14	<0.2	44	17	29	35	90	<0.05	<3	<550	<1700	IS	M	Yes
D221	0-0.9M	<0.1	6	<0.2	38	11	25	24	81	<0.05	<3	<550	<1700	IS	L	No
D221	0.9-1.9M	0.1	15	<0.2	41	16	26	36	95	<0.05	<3	<550	<1700	IS	M	Yes
D214	0-0.9M	<0.1	6	<0.2	43	13	30	26	86	<0.05	<3	<550	<1700	IS	L	No
D214	0.9-1.9M	<0.1	7	<0.2	39	12	27	25	73	<0.05	<3	<550	<1700	IS	L	No
D214	1.9-2.9M	0.1	14	<0.2	42	16	28	33	85	<0.05	<3	<550	<1700	IS	M	Yes
D234	0-0.9M	<0.1	7	<0.2	39	12	27	24	74	<0.05	<3	<550	<1700	IS	L	No
D234	0.9-1.9M	0.1	13	<0.2	45	16	30	31	87	<0.05	<3	<550	<1700	IS	M	Yes
D234	1.9-2.9M	0.1	16	<0.2	44	17	29	36	92	<0.05	<3	<550	<1700	IS	M	Yes
D238	0-0.9M	0.1	8	<0.2	37	12	25	24	75	<0.05	<3	<550	<1700	IS	L	No
D238	0.9-1.9M	0.1	13	<0.2	43	16	29	32	91	<0.05	<3	<550	<1700	IS	M	Yes
D238	1.9-2.9M	0.1	12	<0.2	39	15	26	31	87	<0.05	<3	<550	<1700	IS	L	No
S29		0.2	10	<0.2	27	14	17	24	88	<0.05	<3	<550	<1700	IS	L	No
S30	0-0.9M	<0.1	3	<0.2	29	9	20	20	59	<0.05	<3	<550	<1700	IS	L	No
S30	0.9-1.9M	0.1	14	<0.2	41	16	27	33	90	<0.05	<3	<550	<1700	IS	M	Yes
S30	1.9-2.9M	0.1	14	<0.2	41	15	28	32	90	<0.05	<3	<550	<1700	IS	M	Yes
D272		0.2	12	<0.2	29	18	17	26	75	0.08	<3	<550	<1700	IS	L	No
S32	0-0.9M	0.1	6	<0.2	36	12	25	31	78	<0.05	<3	<550	<1700	IS	L	No
S32	0.9-1.9M	<0.1	4	<0.2	30	9	21	20	65	<0.05	<3	<550	<1700	IS	L	No
S32	1.9-2.9M	<0.1	7	<0.2	37	11	25	23	74	<0.05	<3	<550	<1700	IS	L	No
D298	0-0.9M	0.1	5	<0.2	36	13	24	24	77	<0.05	<3	<550	<1700	IS	L	No
D298	0.9-1.9M	<0.1	6	<0.2	41	13	28	27	84	<0.05	<3	<550	<1700	IS	L	No
D298	1.9-2.9M	0.1	13	<0.2	44	16	29	32	87	<0.05	<3	<550	<1700	IS	M	Yes
S34	0-0.9M	1.2	8	0.2	40	42	24	32	117	0.12	<3	<550	<1700	<15	M	Yes
S34	0.9-1.9M	<0.1	4	<0.2	35	11	24	23	75	<0.05	<3	<550	<1700	IS	L	No
S34	1.9-2.9M	<0.1	7	<0.2	37	11	26	24	76	<0.05	<3	<550	<1700	IS	L	No
S35	0-0.9M	<0.1	5	<0.2	34	10	24	20	65	<0.05	<3	<550	<1700	IS	L	No
S35	0.9-1.9M	<0.1	2	<0.2	19	7	14	17	44	<0.05	<3	<550	<1700	IS	L	No
S35	1.9-2.9M	0.1	14	<0.2	42	17	28	35	91	<0.05	<3	<550	<1700	IS	M	Yes
D320	0-0.9M	0.1	6	<0.2	35	12	24	25	77	<0.05	<3	<550	<1700	IS	L	No
D320	0.9-1.9M	<0.1	4	<0.2	30	9	21	20	64	<0.05	<3	<550	<1700	IS	L	No
D320	1.9-2.9M	<0.1	8	<0.2	36	11	25	23	73	<0.05	<3	<550	<1700	IS	L	No
D330	0-0.9M	<0.1	7	<0.2	27	9	17	18	67	<0.05	<3	<550	<1700	IS	L	No
D330	0.9-1.9M	0.1	8	<0.2	41	13	26	25	95	<0.05	<3	<550	<1700	IS	L	No
D337	0-0.9M	0.1	4	<0.2	18	9	11	18	60	<0.05	<3	<550	<1700	IS	L	No
D337	0.9-1.9M	<0.1	6	<0.2	41	13	26	25	94	<0.05	<3	<550	<1700	IS	L	No
D337	1.9-2.9M	<0.1	6	<0.2	42	13	26	24	94	<0.05	<3	<550	<1700	IS	L	No
S40	0-0.9M	<0.1	6	<0.2	39	12	26	26	87	<0.05	<3	<550	<1700	IS	L	No
S40	0.9-1.9M	<0.1	6	<0.2	17	5	12	13	39	<0.05	<3	<550	<1700	IS	L	No
D355	0-0.9M	<0.1	6	<0.2	40	12	25	23	90	<0.05	<3	<550	<1700	IS	L	No
D355	0.9-1.9M	<0.1	6	<0.2	31	10	19	18	71	<0.05	<3	<550	<1700	IS	L	No
D362	0-0.9M	<0.1	4	<0.2	38	12	26	25	80	<0.05	<3	<550	<1700	IS	L	No
D362	0.9-1.9M	<0.1	5	<0.2	37	12	26	24	78	<0.05	<3	<550	<1700	IS	L	No
S44	0-0.9M	<0.1	5	<0.2	39	13	27	25	82	<0.05	<3	<550	<1700	IS	L	No
S44	0.9-1.9M	<0.1	5	<0.2	39	13	27	27	82	<0.05	<3	<550	<1700	IS	L	No
D374	0-0.9M	<0.1	5	<0.2	38	12	26	26	80	<0.05	<3	<550	<1700	IS	L	No
D374	0.9-1.9M	<0.1	5	<0.2	39	13	26	26	84	<0.05	<3	<550	<1700	IS	L	No
S47	0-0.9M	0.1	10	<0.2	40	12	26	26	88	<0.05	<3	<550	<1700	IS	L	No
S47	0.9-1.9M	<0.1	8	<0.2	40	12	26	24	88	<0.05	<3	<550	<1700	IS	L	No
D378	0-0.9M	0.4	8	<0.2	36	24	23	22	92	0.06	<3	<550	<1700	IS	L	No
D378	0.9-1.9M	0.1	8	<0.2	44	14	29	25	94	<0.05	<3	<550	<1700	IS	L	No
D381	0-0.9M	<0.1	7	<0.2	40	12	24	24	90	<0.05	<3	<550	<1700	IS	L	No
D381	0.9-1.9M	<0.1	5	<0.2	39	12	24	24	87	<0.05	<3	<550	<1700	IS	L	No
D381	1.9-2.9M	<0.1	5	<0.2	41	13	26	24	89	<0.05	<3	<550	<1700	IS	L	No
S50	0-0.9M	<0.1	7	<0.2	38	11	24	24	86	<0.05	<3	<550	<1700	IS	L	No
S50	0.9-1.9M	<0.1	6	<0.2	42	13	26	25	91	<0.05	<3	<550	<1700	IS	L	No
S50	1.9-2.9M	<0.1	6	<0.2	44	13	28	26	94	<0.05	<3	<550	<1700	IS	L	No
D386	0-0.9M	<0.1	6	<0.2	40	12	26	25	89	<0.05	<3	<550	<1700	IS	L	No
D386	0.9-1.9M	<0.1	5	<0.2	38	11	24	24	87	<0.05	<3	<550	<1700	IS	L	No
S1-2	0-0.9M	3.4	10	0.6	52	101	26	46	174	0.18	<3	<550	<1700	IS	H	No*
S1-2	0.9-1.9M	2.6	9	0.4	54	101	26	47	171	0.17	<3	<550	<1700	IS	H	No*
S1-3	0-0.9M	3	12	0.4	59	115	27	40	186	0.23	<3	<550	<1700	IS	H	No*
D1-2	0-0.9M	3.4	7	0.6	60	159	35	40	170	0.14	<3	<550	<1700	IS	H	No*
D6-1	0-0.9M	1.1	8	<0.2	33	50	22	27	99	0.12	<3	<550	<1700	IS	M	Yes
D7-2	0-0.9M	<0.1	2	<0.2	21	7	13	16	47	<0.05	<3	<550	<1700	IS	L	No
D7-2	0.9-1.9M	<0.1	3	<0.2	25	8	17	19	64	<0.05	<3	<550	<1700	IS	L	No
D25-4	0-0.9M	2.6	8	0.4	59	119	28	39	161	0.20	<3	<550	<1700	IS	H	No*
D26-1	0-0.9M	<0.1	3	<0.2	22	7	15	16	53	<0.05	<3	<550	<1700	IS	L	No
D26-1	0.9-1.9M	<0.1	4	<0.2	38	12	27	26	92	<0.05	<3	<550	<1700	IS	L	No
D26-2	0-0.9M	3	8	0.4	58	112	27	37	149	0.11	<3	<550	<1700	IS	H	No*
D39-1	0-0.9M	2.5	8	0.4	59	118	28	37	158	0.15	<3	<550	<1700	IS	H	No*
D39-2	0-0.9M	2.6	8	0.4	54	105	26	37	159	0.13	<3	<550	<1700	IS	H	No*
D45-1	0-0.9M	7	10	0.9	120	253	52	64	245	0.52	<12	<550	<1700	IS	H	No*

Notes:

(1) LMW = Low molecular weight PAHs, that is, acenaphthene, acenaphthylene, anthracene, fluorene, naphthalene and phenanthrene.

(2) HMW = High molecular weight PAHs, that is, benzo[a]anthracene, benzo[a]pyrene, chrysene, dibenzo[a,h]anthracene, fluoranthene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene and benzo[g,h,i]perylene.

(3) Values bold indicate Category M sediment under ETWB TCW No. 34/2002.

(4) Values in underlined indicate Category H sediment under ETWB TCW No. 34/2002.

(5) Values in bold and underlined indicate Category H sediment under ETWB TCW No. 34/2002 and that the contaminant level exceeded the LCEL by 10 times.

(6) Total PCB: None of the 18 PCB congeners were found in the samples.

(7) “IS” indicated insufficient interstitial water for TBT Analysis.

(8) ^# In accordance with ETWBTC (Works) No. 34/2002, sediment with the following category:

L means Category L Material, ≤Lower Chemical Exceedance Level

M means Category M Material, >Lower & ≤Upper Chemical Exceedance Level (Type 1 Open Sea Disposal (Dedicated Site) or Type 2 Confined Marine depending on passing or failing biological screening tests respectively)

H means Category H Material, >Upper Chemical Exceedance Level (Type 2 Confined Marine Disposal – please see note (9))

(9) *In accordance with ETWB TC (Works) No. 34/2002, Cat H material of which chemical screening results >Upper Chemical Exceedance Level & <10 x Lower Chemical Exceedance Level, biological screening test is not required. Under the current arrangement, this material is classified as Type 2 confined marine disposal

(10) Type 1 Open Sea Disposal – Category L Sediment; Type 1 Open Sea Disposal (Dedicated Site) – Category M (pass biological screening test); Type 2 Confined Marine Disposal – Category M (failed biological screening test) and Category H (chemical screening results >Upper Chemical Exceedance Level & <10 x Lower Chemical Exceedance Level)

A summary of classification of the samples is provided in Table 4.4. The majority of the sediment samples was classified as Category L.

Table 4.4: Summary of Classification of Samples after passing Chemical Screening Test

Category	Number of Samples
Category L	83
Category M	29
Category H*	14

*In accordance with ETWB TC (Works) No. 34/2002, Cat H material of which chemical screening results >Upper Chemical Exceedance Level & <10 x Lower Chemical Exceedance Level, NO biological screening test is required. Under the current arrangement, this material is classified as Type 2 confined marine disposal

4.3.2.3 Biological Screening

The marine sediment quality analysis results of biological screening from the site investigation works were presented in a comprehensive laboratory testing report and is provided in Appendix 4.4.

The general characteristic of the marine sediment is provided in the ancillary tests results summarised in Table 4.5.

Table 4.5: Summary of Ancillary Tests Results

Sample ID		Interstitial ammonia (mgNH3/L)	Interstitial salinity (ppt)	Grain Size < 63µm (%)	Moisture Content (%)	TOC (% Wet Weight)
S5-2	0-0.9M	38.10	32	76.6	38.30	0.45
S5-2	0.9-1.9M	4.36	34	96.8	43.00	0.58
S6	0-0.9M	25.50	34	85.7	49.30	0.76
S6	0.9-1.9M	24.00	34	89.2	49.20	0.61
S6	1.9-2.9M	23.60	33	38.3	19.80	0.10
S8	0.9-1.9M	NA	NA	92.1	44.30	0.46
S9	0-0.9M	24.20	32	84.9	44.60	0.58
S9	0.9-1.9M	NA	NA	98.5	35.40	0.47
S11	0-0.9M	3.58	34	89.7	48.50	0.49
S11	0.9-1.9M	NA	NA	98.3	40.90	0.52
S12	0.9-1.9M	14.30	33	94.7	47.40	0.47
S15	0-0.9M	26.60	33	84.8	47.20	0.68
S21	0.9-1.9M	24.50	32	95.1	46.40	0.52
S30	0.9-1.9M	48.10	28	92.2	45.40	0.70
S30	1.9-2.9M	50.90	28	93.0	43.80	0.57
S34	0-0.9M	10.20	33	89.0	49.30	0.94
S35	1.9-2.9M	55.00	31	86.5	44.50	0.50
D174	1.9-2.9M	14.10	35	91.1	46.60	0.61
D196	0-0.9M	3.48	33	95.2	45.80	0.60
D196	0.9-1.9M	7.72	33	97.2	43.60	0.76
D196	1.9-2.9M	NA	NA	99.0	40.00	0.67
D202	1.9-2.9M	31.80	29	88.8	45.30	0.58
D214	1.9-2.9M	30.60	2.9	90.1	44.10	0.61
D221	0.9-1.9M	5.68	34	94.6	46.00	0.62
D234	0.9-1.9M	27.30	30	85.4	45.00	0.62
D234	1.9-2.9M	34.80	28	89.5	43.90	0.59
D238	0.9-1.9M	48.60	27	90.3	45.60	0.61
D298	1.9-2.9M	NA	NA	89.5	41.10	0.65

Note: 1. Analysis was not performed due to insufficient amount of porewater obtained.

The sediment biological screening results indicated that some of the samples failed the toxicity tests. The sediment is deemed to have failed the biological test if it fails in any one of the three toxicity tests. A summary of toxicity tests is provided in Table 4.6.

Table 4.6: Summary of Toxicity Test Failure

Sample ID	Sample Depth	Classification after Chemical Screening	Test			Biological Screening Results
			Amphipod	Polychaete	Bivalve Larvae
S5-2	0-0.9M	Category M	Fail	Pass	Pass	Fail
S5-2	0.9-1.9M	Category M	Fail	Fail	Fail	Fail
S6	0-0.9M	Category M	Pass	Pass	Fail	Fail
S6	0.9-1.9M	Category M	Pass	Fail	Pass	Fail
S6	1.9-2.9M	Category M	Fail	Pass	Pass	Fail
S8	0.9-1.9M	Category M	Pass	Pass	Pass	Pass
S9	0-0.9M	Category M	Pass	Fail	Pass	Fail
S9	0.9-1.9M	Category M	Pass	Fail	Pass	Fail
S11	0-0.9M	Category M	Pass	Pass	Fail	Fail
S11	0.9-1.9M	Category M	Pass	Fail	Fail	Fail
S12	0.9-1.9M	Category M	Pass	Pass	Pass	Pass
S15	0-0.9M	Category M	Fail	Fail	Fail	Fail
S21	0.9-1.9M	Category M	Pass	Pass	Fail	Fail
S30	0.9-1.9M	Category M	Pass	Pass	Pass	Pass
S30	1.9-2.9M	Category M	Pass	Pass	Fail	Fail
S34	0-0.9M	Category M	Pass	Pass	Pass	Pass
S35	1.9-2.9M	Category M	Pass	Pass	Fail	Fail
D174	1.9-2.9M	Category M	Pass	Pass	Pass	Pass
D196	0-0.9M	Category M	Pass	Pass	Fail	Fail
D196	0.9-1.9M	Category M	Fail	Pass	Fail	Fail
D196	1.9-2.9M	Category M	Pass	Fail	Pass	Fail
D202	1.9-2.9M	Category M	Pass	Fail	Pass	Fail
D214	1.9-2.9M	Category M	Pass	Pass	Pass	Pass
D221	0.9-1.9M	Category M	Pass	Fail	Fail	Fail
D234	0.9-1.9M	Category M	Pass	Pass	Pass	Pass
D234	1.9-2.9M	Category M	Pass	Pass	Pass	Pass
D238	0.9-1.9M	Category M	Pass	Pass	Fail	Fail
D298	1.9-2.9M	Category M	Pass	Fail	Fail	Fail
D6-1	0-0.9M	Category M	Pass	Pass	Pass	Pass

4.4 Identification and Evaluation of Environmental Impacts

4.4.1 Construction Phase

The construction activities to be carried out for the proposed dredging activities 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

¡ Construction and demolition (C&D) materials

¡ General refuse; and

¡ Chemical waste;

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

4.4.1.1 Marine Dredged Sediment

To achieve the enhanced navigation depth, dredging of the seabed to -17.5mCD is required. In accordance with ETWB TCW No. 34/2002, reviews of existing information for site contamination assessment (Tier I), chemical screening (Tier II) and biological screening (Tier III) were conducted along the proposed dredged areas to determine the sediment quality. Sediment was classified into Category L, M and H based on its contaminant levels identified from chemical screening. Sediment classified as Category M and Category H (with level exceeding 10 times LCEL) was then subjected to biological screening. The corresponding types of disposal required were thus identified and presented graphically in Figure 4.3

In accordance with ETWB TCW No. 34/2002, the disposal options of the sediment and the estimated quantities of different types of marine sediment to be dredged for disposal are summarized in Table 4.7.

Table 4.7 Estimated Quantity of Different Types of Marine Sediment to be Dredged for Disposal

Sediment Type^#	Estimated Quantity (m^3)
Type 1- Open Sea Disposal (Category L Sediment )	1,816,560
Type 1- Open Sea Disposal (Dedicated Sites) (Category Mp Sediment)	1,102,148
Type 2 - Confined Marine Disposal (Category Mf Sediment and Category H* Sediment)	1,501,676 (Category Mf Sediment - 711,120 and Category H* Sediment - 790,556)

^# In accordance with ETWBTC (Works) No. 34/2002, sediment with the following category:

L means Category L Material, ≤Lower Chemical Exceedance Level

M_f means Category M Material, >Lower & ≤Upper Chemical Exceedance Level and has failed biological screening test

H means Category H Material, >Upper Chemical Exceedance Level & <10 x Lower Chemical Exceedance Level and biological screening test is not required

H_p means Category H Material, >Upper Chemical Exceedance Level & >10 x Lower Chemical Exceedance Level and has passed biological screening test

H_f means Category H Material, >Upper Chemical Exceedance Level & >10 x Lower Chemical Exceedance Level and has failed biological screening test

* In accordance with ETWB TC(W) No. 34/2002, no biological screening test is required for those Cat H with chemical screening results >Upper Chemical Exceedance Level & <10 x Lower Chemical Exceedance Level. By definition, this material belong to Type 2 Confined Marine Disposal

Waste Reduction Option

Since this Project involves deepening of the container basin and its approach channel to provide sufficient depth for ULCS, the option for reducing the amount of sediment removal is limited. However, it should be stressed that the initial estimate of the dredged volume given in the Study Brief of 5.5Mm³ has been reduced to 4.4Mm³ through detailed surveys and engineering design as part of this Assignment. This, on itself, constitutes a significant reduction in the extent of material to be dredged and disposed of for this Project.

Sediment Handling Options

In determining the option for sediment treatment, various factors were considered, including Project timeframe, availability and feasibility of treatment options to determine whether treatment of dredged sediment would be feasible, with disposal being the last resort. A separate Study on the Options for Management of Contaminated Sediment in Hong Kong^[1] (commissioned by CEDD) was reviewed in order to identify any feasible alternatives for marine disposal which could be applied to this Project. The CEDD Study, however, ruled out ex-situ treatment options on the grounds of high cost, technical infeasibility and land requirements. Regarding the opportunity for reusing the sediment, many options such as using dredged sediment as fill in reclamation, polders and mudflats were similarly rejected, along with concerns for environmental impact of such schemes. A summary of the review is provided in Appendix 4.5.

Potential Environmental Effects

The potential environmental effects relating to the removal of dredged sediments on water quality have been assessed and presented in Section 3 of this Report. To minimize any potential adverse impacts arising from the dredged marine sediment, the sediment will be dredged, transported and disposed of in a manner that will minimise the loss of contaminants either into solution or by resuspension. Mitigation measures to minimise potential environmental impacts in relation to waste handling are described in Section 4.5. With the implementation of mitigation measures, no unacceptable impacts would be expected from the transportation and disposal of the dredged sediment.

4.4.1.2 Construction and Demolition (C&D) Materials

The Project also includes the removal of portions of outfall/diffusers of the Kwai Chung and Tsing Yi submarine sewage outfalls above the proposed dredging level, i.e. -17.5mCD. The existing material above the proposed dredging level surrounding the submarine outfall will also be removed. These materials would amount to less than 500 m³. It is anticipated that the rock and rubble generated from the removal of the submarine outfalls will not be dredged during the dredging process and all these material will remain on the sea bed.

4.4.1.3 General Refuse

The construction workforce will generate refuse comprising food scraps, waste paper, empty containers, etc. Such refuse will be properly managed so that intentional or accidental release to the surrounding environment does not occur. Disposal of refuse from sites other than the approved waste transfer or disposal facilities shall be prohibited. Effective collection of site wastes will be required to prevent waste materials being blown around by wind, flushed or leached into the marine environment, or to prevent creating odour nuisance or pest and vermin problem. Waste storage areas will be well maintained and cleaned regularly. With the implementation of good waste management practices on site, adverse environmental impacts are not expected to arise from the storage, handling and transportation of workforce wastes.

The maximum number of construction workers to be employed is estimated to be less than 100 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 65 kg. This waste can be effectively controlled by standard waste collection and disposal arrangements.

4.4.1.4 Chemical Waste

The maintenance and servicing of construction plant and equipment may generate some chemical wastes such as cleaning fluids, solvents, lubrication oil and fuel. Maintenance of vessels may also involve the use of a variety of chemicals, oil and lubricants. 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 Waste Management Plan to be prepared by the Contractor.

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 and associated adverse impacts on marine biota; and

¡ Fire hazards.

Materials classified as chemical wastes would require special handling and storage arrangements before removal for appropriate treatment at the approved Chemical Waste Treatment Facility. Wherever possible opportunities should be taken to reuse and recycle materials. Mitigation and control requirements for chemical wastes are detailed in Section 4.5.3. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected.

4.4.2 Operation Phase

No C&D material will be generated during the operational phase.

4.4.2.1 Maintenance Dredging

From the information provided in Section 2.7, it is anticipated that maintenance dredging will be carried out on an infrequent basis with dredged sediment quantities amounting to approximately 30,000 m³ annually for this Project. Based on the past record from Port Works Department (PWD), it is anticipated sediment dredged from the container basin is disposed as Type 2 (Confined Marine Disposal) material. For the fairways, both Type 1 (Open Sea Disposal) and Type 2 (Confined Marine Disposal) disposal will be expected. As the scale of disposal during operation phase (i.e., from maintenance dredging) is considered much smaller than under the capital works for this Project, there will not be any significant influence to the environment and disposal ground as a result of dredging and disposal expected.

Nevertheless, ETWB TCW No. 34/2002, “Management of Dredged/Excavated Sediment” sets out the procedures for sediment sampling and testing and disposal. For small scale dredging works of maintenance in nature and involving dredging volumes of less than 5,000m³ in situ, DEP may waive the sediment sampling and testing requirements. Previously obtained data or history of the sediment in the vicinity should be submitted to Director of Environmental Protection (DEP) for consideration for disposal arrangement.

4.5 Mitigation of Adverse Environmental Impacts

4.5.1 Good Site Practices

Adverse impacts relating to waste management such as odour, noise and wastewater discharge are not expected to arise, provided that good site practices are strictly followed. Recommendations for good site practices during the construction activities include:

¡ Obtain the profile of different sediment categories and careful planning of sediment removal;

¡ Strictly follow various mitigation measures for protecting water quality as described in water quality section;

¡ Nomination of an approved person, such as a site manager, to be responsible for good site practices, arrangements for collection and effective disposal to an appropriate facility, of all wastes generated at the site;

¡ Training of site personnel in proper waste management and chemical handling procedures;

¡ Provision of sufficient waste disposal points and regular collection of waste;

¡ Barges filled with dredged sediment shall be towed away immediately for disposal. In so doing, odour is not anticipated to be an issue to distant sensitive receivers;

¡ Well planned delivery programme for offsite disposal such that adverse environmental impact from transporting sediment material is not anticipated; and

¡ Use well maintained PME on site.

4.5.2 General Refuse

General refuse will be stored in enclosed bins. A reputable waste collector will be employed by the contractor to remove general refuse from the site.

4.5.3 Chemical Waste

If chemical wastes are produced at the construction site, 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. Good quality containers compatible with the chemical wastes should be used, and incompatible chemicals shall be stored separately. Appropriate labels shall be securely attached on each chemical waste container indicating the corresponding chemical characteristics of the chemical waste, such as explosive, flammable, oxidizing, irritant, toxic, harmful, corrosive, etc. The Contractor shall use a licensed collector to transport and dispose of the chemical wastes, to either the approved Chemical Waste Treatment Centre, or another licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.

4.5.4 Marine Dredged Sediment

The basic requirements and procedures for dredged/excavated sediment disposal are specified under the ETWB TCW No. 34/2002 Management of Dredged/Excavated Sediment. The management of the dredging/excavation, use and disposal of marine sediment is monitored by the Marine Fill Committee (MFC), while the licensing of marine dumping is the responsibility of the Director of Environmental Protection (DEP).

The sediment shall be dredged and transferred to barges for subsequent disposal as allocated by MFC depending on the level of contamination. Release of dredged sediment into the surrounding water shall be avoided. 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 seawater.

Category M_p, M_f and H (sediment not required to undergo biological screening test) material was identified at the dredging site in this assessment. Under the current disposal planning, Category M_p sediment is to be dredged and disposed of at South Brothers Confined Marine Disposal Facilities (Type 1 Open Sea Disposal (Dedicated Site)) or alternatively at a cross boundary disposal facility, subject to the confirmation of MFC and the Mainland Authority. Category M_f and H sediment, on the other hand, will go to the confined marine disposal facilities (Type 2 Confined Marine Disposal) in South Brothers Confined Marine Disposal Facilities which have been indicated by MFC to have sufficient capacity to cater for the sediment generated from this Project.

For Category L material, which is suitable for Type 1 Open Sea Disposal in accordance with ETWB TCW no. 34/2002, sites would be assigned for disposal locations such as South Cheung Chau Open Sea Disposal Area, East Ninepin Open Sea Disposal Area or other designated locations.

Under the Dumping at Sea Ordinance (DASO), a Sediment Quality Report (SQR) is to be prepared for EPD’s approval under DASO before dumping permit is granted. The disposal arrangement as identified for this Project will be subject to procedural agreement from MFC. The Project works will not be carried out before obtaining confirmation from MFC on the disposal option.

Typically, if Category H_f sediment is present, special disposal arrangements will be required. The EIA report for “Wan Chai Development Phase II and Central-Wan Chai Bypass”[2] proposed the use of geosynthetic container system for disposal of Type 3 sediment. Field trial test by using uncontaminated mud demonstrated its feasibility with negligible loss of contaminants for disposal of Category H_f sediments. The proposed system is shown to be an effective system with negligible loss of contaminants to the environment during disposal. The arrangement of Type 3 sediment encountered in this Project could possibly follow this method where the dredged sediments are sealed in geosynthetic containers and, at the disposal site, the containers to be dropped into the designated contaminated mud pit where they would be covered by further mud disposal and later by the mud pit capping, thereby meeting the requirements for fully confined mud disposal. For the size and the specification of the geosynthetic container, reference is made to the study report from Wan Chai Development Phase II, Design and Construction (D&C) Consultancy (Agreement No. CE54/2001 (CE)) attached in Appendix 6.2 of the EIA Report for Wan Chai Development Phase II and Central-Wan Chai Bypass. The study report mentioned five types of geosynthetic containers and trial test was carried out to confirm the effectiveness of the disposal system. The report recommended that the use of 300m³ geosynthetic container, with outer woven fabric tensile strength of 200 kN/m and seam strength of 140 kN/m, would be the effective method for contained disposal which meets ETWB TCW No. 34/2002 requirements, and for assuring negligible loss of contaminants to the marine environment during disposal. The detailed specification could be referred in Table 4.4 and Section 6.3.6 of this Wan Chai Study Report.

MFC is responsible for the allocation of disposal locations for which details are included in the permit issued by EPD under Dumping at Sea Ordinance (DASO Permit). Environmental monitoring program on water quality is currently implemented, particularly at the East Sha Chau dumping to monitor the environmental impacts due to the mud pits operation.

4.5.5 Handling Rate and Frequency of Barge Movements and Routings

As mentioned in Section 3, the maximum dredging rate is 4,000 m³ per grab dredger per day during the dredging operations. A maximum of three grab dredgers will operate on a daily basis resulting in 12,000 m³ of dredged material arising per day. The proposed frequency of barge movements and transportation routing are shown in Table 4.8.

Table 4.8: Summary of Dredging Rate, Manoeuvring of Dredgers and Disposal Routings*

Sediment Type	Dredging Rate	Manoeuvring of Dredgers	Proposed Routing for Disposals^#
Type 1- Open Sea Disposal (Category L Sediment)	Up to maximum 12,000 m^3 per day	Maximum 3 dredgers will operate at any one time across all works areas per day	South Cheung Chau Open Sea Disposal Area, East Ninepin Open Sea Disposal Area or other designated locations
Type 1- Open Sea Disposal (Dedicated Sites) (Category Mp Sediment)			South of Brothers Confined Marine Disposal Facilities^+ or Cross boundary disposal arrangement (alternative option)^
Type 2 - Confined Marine Disposal (Category Mf and Category H Sediment)			South of Brothers Confined Marine Disposal Facilities^+

* Condition 3.4.6.2 (ii)(c) of EIA Study Brief refers

^# The disposal options as identified in this Project will be subject to confirmation from MFC. The Project works will not be carried out before obtaining confirmation from MFC on the disposal option

^ Category M_p sediment is to be dredged and disposed of at South Brothers Confined Marine Disposal Facilities (Type 1 Open Sea Disposal (Dedicated Site)) or alternatively at a cross boundary disposal facility, subject to the confirmation of MFC and the Mainland Authority

⁺ The sufficiency of the sediment disposal capacity to cater for the demand from the captioned project is subject to the availability of the confined marine disposal facility at South of Brothers

The project involves only mainly soft sediment dredging works. Use of barging points, conveyor systems or stockpiling areas will not be required. Agreement from Marine Fill Committee for the dredging rationale and dumping sites allocation were obtained as presented in Appendix 4.6.

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 3 of this Report should be strictly followed. Furthermore, the dredged sediment of Category M and H must be effectively isolated from the environment upon final disposal and shall be disposed of at designated Contaminated Mud Pits. The marine sediments would require disposal to a suitable marine disposal location, either in Hong Kong or in the Mainland China (for those Category M sediment passing biological tests), subject to the confirmation of MFC and the Mainland Authority.

During transportation and disposal of the dredged marine sediments for Type 1 and Type 2 disposal (ETWB TCW no. 34/2002 refers), the following measures shall be taken to minimise potential impacts on water quality:

¡ Bottom opening of barges will 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.

¡ Strictly follow all conditions stipulated in the dumping permit.

Potential environmental impacts arising from handling activities, collection, transportation and disposal of waste are expected to be minimal with the implementation of appropriate mitigation measures as recommended above and in relevant sections of this Report.

Table 4-9 provides a summary of the various waste types likely to be generated during the construction activities for the proposed dredging works and during maintenance dredging together with the recommended handling and disposal methods.

Table 4.9: Summary of Waste Handling Procedures and Disposal Routes*

Waste Material Type	Generated from works item	Timing to be Generated	Total Quantity Generated	Quantity to be disposed off-site	Proposed Disposal Options^##	Handling
Construction phase
Marine Dredged Sediment Type 1, Open Sea Disposal (Category L Sediment)	Dredging	Second half of 2011 to second half of 2013	1,816,560 m^3	1,816,560 m^3	South Cheung Chau Open Sea Disposal Area, East Ninepin Open Sea Disposal Area or other designated locations	Minimise resuspension by use of closed grab, controlled loading and transfer
Marine Dredged Sediment Type 1, Open Sea Disposal (Dedicated Sites) (Category Mp Sediment )	Dredging	Second half of 2011 to second half of 2013	1,102,148 m^3	1,102,148 m^3	South of Brothers Confined Marine Disposal Facilities or Cross boundary disposal arrangement (alternative option)^	Minimise resuspension by use of closed grab, tight seal on barges, controlled loading and transfer
Marine Dredged Sediment Type 2, Confined Marine Disposal (Category Mf and Category H^+ Sediment)	Dredging	Second half of 2011 to second half of 2013	1,501,676 m^3	1,501,676 m^3	South of Brothers Confined Marine Disposal Facilities	Minimise resuspension by use of closed grab, tight seal on barges, controlled loading and transfer
C&D Material	Remove the portions of outfall/diffusers above the proposed dredging level at Kwai Chung and Tsing Yi submarine outfalls	Second half of 2011 to second half of 2013	<500m^3 (preliminary estimate)	Remain on sea bed	Remain on sea bed	-
General Refuse	Waste paper, discarded containers, etc. generated from workforce	Second half of 2011 to second half of 2013	65 kg per day (preliminary estimate based on workforce of 100)	65 kg per day	Refuse station for compaction and containerisation and then to landfill	Provide on-site refuse collection points
Chemical Waste	Cleansing fluids, solvent, lubrication oil and fuel from construction plant and equipment	Second half of 2011 to second half of 2013	Few cubic metres per month (preliminary estimate)	Few cubic metres per month (preliminary estimate)	Chemical Waste Treatment Centre	Recycle on-site or by licensed companies. Stored on-site within suitably designed containers

* Condition 3.4.6.2 (ii)(c) of EIA Study Brief refers

^# Please refer Section 2.7 regarding the need of maintenance dredging

^##The disposal options as identified in this Project will be subject to confirmation from MFC. The Project works will not be carried out before obtaining confirmation from MFC on the disposal option

^ Category M_p sediment is to be dredged and disposed of at South Brothers Confined Marine Disposal Facilities (Type 1 Open Sea Disposal (Dedicated Site)) or alternatively at a cross boundary disposal facility, subject to the confirmation of MFC and the Mainland Authority

+ The Category H sediment found in this Project are with chemical screening results exceeded the Upper Chemical Exceedance Level but not exceeding 10 times Lower Chemical Exceedance Level. NO biological screening test is therefore required. Under the current arrangement, this sediment belongs to Type 2 Confined Marine Disposal arrangement.

### In accordance with ETWBTC (Works) No. 34/2002, sediment with the following category:

L means Category L Material, ≤Lower Chemical Exceedance Level

Mf means Category M Material, >Lower & ≤Upper Chemical Exceedance Level and has failed biological screening test

H means Category H Material, >Upper Chemical Exceedance Level & <10 x Lower Chemical Exceedance Level and biological screening test is not required

(By definition, this material belong to Type 2 Confined Marine Disposal)

Hp means Category H Material, >Upper Chemical Exceedance Level & >10 x Lower Chemical Exceedance Level and has passed biological screening test

Hf means Category H Material, >Upper Chemical Exceedance Level & >10 x Lower Chemical Exceedance Level and has failed biological screening test

4.6 Evaluation of Residual Impacts

With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified wastes, no adverse residual impact is expected during the proposed dredging works.

4.7 Environmental Monitoring and Audit

Waste management will be the contractor’s responsibility to ensure that all wastes produced during the construction of the Project are handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements. The recommended mitigation measures will form the basis of the site Waste Management Plan which becomes part of the Environmental Management Plan according to the requirements as stipulated in ETWB TCW No. 19/2005, which is to be developed by the Contractor in the construction phase.

During construction phase, auditing of each waste stream will be carried out periodically to determine if wastes are being managed in accordance with approved procedures and the site Waste Management Plan. The audits should look at all aspects of waste management including waste generation, storage, recycling, treatment, transport and disposal. An appropriate audit programme would be to undertake a first audit at the commencement of the construction works, and then to audit regularly thereafter.

4.8 Summary

A review of the sediment quality data from the marine site investigation indicated that the majority of the marine sediment to be dredged along the proposed dredging area was classified as Category L (for Type 1, Open Sea Disposal). The total volume of dredged sediment requiring marine disposal is estimated to be 4,420,384 m³. The volume of dredged sediment suitable for open sea disposal (Type 1, Category L sediment) is estimated to be 1,816,560 m³. The volume of dredged sediment suitable for open sea disposal at dedicated sites (Type 1 Open Sea Disposal (Dedicated Sites), Category M_p sediment) is estimated to be 1,102,148 m³. The volume of contaminated sediment requiring confined marine disposal (Type 2, Confined Marine Disposal, Category M_f and H sediment) is estimated to be 1,501,676 m³.

Based on the above findings, the proposed dredge level has achieved a balance between meeting the technical requirements for access of ULCS, with allowance of potential siltation, and minimizing the volume of sediment to be disposed, from an environmental perspective. After reviewing of the various sediment treatment options, it is considered that marine disposal is the preferred option taking into account of the various constraints including costs, time frame and land availability.

Maintenance dredging during operation phase is anticipated. The quantity of the dredged sediment is considered insignificant as compared with the extent of this Project.

Provided that these wastes are handled, transported and disposed of using approved methods and that the recommended good site practices are strictly followed, adverse environmental impacts is not expected.

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[1] Ove Arup & Partners Hong Kong Ltd (2008). Agreement No. FM 01/2007 – Review of Options for Management of Contaminated Sediment in Hong Kong. Final Report (Rev A). August 2008.

[2] Maunsell Consultants Asia Ltd. (Oct 2007). Agreement No. CE 54/2001 (CE), Wan Chai Development Phase II and Central-Wan Chai Bypass, Environmental Impact Assessment Report