6. WASTE management

6.1 Introduction

6.1.1 This waste assessment examines the type, quantity, quality and timing of potential sources of waste that will arise during the construction and operation phases of the Project. It identifies potential environmental impacts associated with their handling and disposal. Options for avoidance, minimization, reuse, recycling, treatment, storage, collection, transport and disposal of such wastes are examined.

6.1.2 Where unacceptable impacts are identified, appropriate mitigation measures and good site practices are recommended. Disposal options will be outlined for each type of waste, and the responsibilities for disposal or recycling discussed.

6.1.3 The main objectives of the waste assessment are to:

(i) identify the sources, volumes, quality and timing of wastes arising from the construction activities;

(ii) recommend construction waste management requirements in terms of minimisation through project design, construction method, and site location, identification of reuse and recycling opportunities and the responsible party for each step of the waste management process; and

(iii) recommend disposal sites and routes for different types of wastes unsuitable for reuse or recycling.

6.1.4 The recommendations will be carried out in accordance with the current requirements for waste management.

6.2 Relevant Legislation, Policies, Standards and Criteria

Legislation, Circulars, Guidelines related to Waste Management

6.2.1 The following legislation relates to the handling, treatment and disposal of wastes and will be used in assessing potential impacts:

· Environmental Impact Assessment Ordinance (Cap.499)

· Waste Disposal Ordinance (Cap.354)

· Waste Disposal (Chemical Waste) (General) Regulation

· Land (Miscellaneous Provisions) Ordinance (Cap.28)

· Public Health and Municipal Services Ordinance (Cap.132) – Public Cleansing and Prevention of Nuisances Regulation

· Dumping at Sea Ordinance (Cap.466)

· Technical Memorandum on Environmental Impact Assessment Process

6.2.2 The following documents, circulars and guidelines which relate to waste management and disposal will also be referred to during this study:

· Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) - Annex 7 - Criteria for Evaluating Waste Management Implications and Annex 15 - Guidelines for Assessment of Waste Management Implications

· Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes, EPD (1992)

· WBTC No. 2/93 - Public Dumps

· WBTC No. 2/93B - Public Filling Facilities

· WBTC No. 16/96 - Wet Soil in Public Dumps

· WBTC No. 4/98 & 4/98A - Use of Public Fill in Reclamation and Earth Filling Projects

· WBTC No. 25/99, 25/99A & C - Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers

· WBTC No. 12/2000 - Fill Management

· WBTC No. 19/2001 - Metallic Site Hoardings and Signboards

· WBTC No. 12/2002 - Specifications Facilitating the Use of Recycled Aggregates

· ETWB TCW No. 33/2002 - Management of Construction and Demolition Material including Rock

· ETWB TCW No. 34/2002 - Management of Dredged/Excavated Sediment

· ETWB TCW No. 24/2004 - Specifications Facilitating the Use of Concrete Paving Units Made of Recycled Aggregates

· ETWB TCW No. 31/2004 - Trip-ticket System for Disposal of Construction & Demolition Material

· ETWB TCW No. 19/2005 - Environmental Management on Construction Sites

Sediment Quality

6.2.3 The procedures for assessing and classifying sediment and the management framework of disposing such sediment are outlined in the ETWB TCW No. 34/2002. The sediment quality criteria for the classification of sediment are presented below in Table 6.1.

Table 6.1

Sediment Quality Criteria for the Classification of Sediment

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

* The contaminant level is considered to have exceeded the UCEL if it is greater than the value shown.

PAH= polyaromatic hydrocarbon

PCB= polychlorinated biphenyl

6.2.4 The sediment is classified into 3 categories based on its contaminant levels:

§ Category L: Sediment with all contaminant levels not exceeding the Lower Chemical Exceedance Level (LCEL). The material must be dredged, transported and disposed of in a manner which minimizes the loss of contaminants either into solution or by resuspension.

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

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

6.2.5 Depending on the level of contamination, disposal options for the excavated sediments included the following:

§ Type 1 – Open Sea Disposal

§ Type 1 – Open Sea Disposal (Dedicated Sites)

§ Type 2 – Confined Marine Disposal

§ Type 3 – Special Treatment / Disposal

6.3 Assessment Methodology

6.3.1 Reference has been made to the methodology laid out in the EIAO-TM (Annexes 7 and 15). The principal legislation regulating waste is the Waste Disposal Ordinance (WDO) (Cap.354).

6.3.2 Procedures on the assessment and classification of sediment, the sampling and testing procedures and the disposal arrangements are listed out in the ETWB TCW No. 34/2002 – “Management of Dredged/Excavated Sediment”.

6.4 Sources and Types of Waste arising from the Project

Introduction

6.4.1 The proposed drainage channel works include the following construction activities:

· site clearance and demolition of temporary structures to form works area;

· excavation and formation of channel;

· construction of channel linings and structures;

· construction of maintenance access road, footbridges, box culverts, installation of pipes and other ancillary structures; and

· planting and landscaping works.

6.4.2 Construction activities will result in the generation of a variety of Construction and Demolition (C&D) materials. The C&D materials are usually mixed consisting of inert components (public fill) such as soil, rock, concrete, brick, and asphalt, etc and non-inert components (C&D waste) comprising metal, timber, paper, plastic and general garbage. Chemical and municipal wastes may also arise as a result of construction activities. The likely waste generated from the construction of the proposed drainage channel can be classified into the following main categories:

· site clearance / demolition materials;

· excavated materials;

· chemical waste; and

· general works waste.

6.4.3 During operation period, only a small amount of excess silty material and vegetation will be generated from the maintenance of the channel during dry season. Likewise, very minimal amount of litter is expected from the usage of the proposed access road and viewing point and carpark.

6.4.4 Handling and disposal of the above mentioned wastes may cause environmental impacts and nuisance if it is not properly managed.

Site Clearance / Demolition Materials

6.4.5 Site clearance and demolition works will be required, thus generating unwanted material during construction.

6.4.6 The Project will require to demolish a number of squatter houses and temporary structures. Site clearance / demolition works will involve the removal of vegetation (mainly grasses and shrubs) and some trees, demolition of structures (mostly temporary structures and a few squatter houses) and removal of a small portion of available topsoil.

6.4.7 Demolition of temporary structures and squatter houses will generate concrete rubbles, plastics, metals, glasses, asphalts, wood and refuse. As these materials are likely to be in deteriorating condition, potential for reuse of such materials on site is very limited.

Excavated Materials

6.4.8 The majority of C&D materials generated from the Project will arise during the excavation and formation of the channel. It is expected that most of this material will be muddy deposits, top soil, sand, gravel and some underlying rock.

6.4.9 Some suitable material may be generated from excavation of the stream bed. This material can be mixed with topsoil and stockpiled for later landscaping use. Rocks, cobbles and other suitable material from existing stream bed should be stockpiled for later reused for backfilling or as stream bed materials subject to the size requirement.

6.4.10 The potential for reuse of suitable excavated materials should be explored at the early stage of the Project.

Excavated Sediment

6.4.11 Approximately 2,900 m³ of stream sediment will need to be excavated for the Project.

6.4.12 A sediment quality characterisation survey was carried out in January 2008 as part of the Ground Investigation (GI) Study under this Project to characterise the level of contamination in the sediment of the existing stream course. A subsequent survey was conducted in November 2008 for portion of the downstream section that will need to be excavated to accommodate a maintenance access. The locations of the sample are shown in Figure 6.1.

6.4.13 The proposed sampling locations are chosen to verify the extent of contaminated sediment in the natural stream. The sampling locations are chosen in the natural stream bed, excluding section of the stream to be retained and all existing engineering channels within the site, assuming that any contaminated sediment beneath the existing engineering channels was removed during their construction. Based on the current design, a small amount of sediment will be excavated at the downstream portion of the channel (Figure 6.1).

6.4.14 A detailed Sediment Quality Report (SQR) is conducted in March 2008 for the January 2008 survey in accordance with ETWB TCW No. 34/2002 to confirm the degree of sediment contamination, if presence, and to estimate the volume of sediment that required disposal such that appropriate disposal sites can be allocated by the relevant authorities. For the November 2008 survey, the detailed SQR is pending subject to the results of the biological screening test.

6.4.15 All samples were tested for all contaminants by a HOKLAS laboratory with analytical methods as stipulated in ETWB TCW No. 34/2002 or in-house methods approved by EPD.

6.4.16 The chemical testing results of the sediment samples are shown in Tables 6.2a & 6.2b with the laboratory report presented in Appendix 6.1.

6.4.17 Sediment testing results for the January 2008 survey indicated that heavy metals, particularly Lead (Pb) and Zinc (Zn) were high at 2 of the 3 sediment quality sampling locations (SD1 & SD2), where sediments are classified as Category H. Sediments found in SD3 are found to be uncontaminated and hence can be classified as Category L. Sampling location SD3 is close to the portion of the stream in which the stream bed section will be retained in-situ. Biological screening is not necessary as the Category H material does not exceed the 10x LCEL as required under ETWB TCW No. 34/2002. In accordance with ETWB TCW No. 34/2002, for sediment classified as Category L, the disposal option is Type 1 – Open Sea Disposal whereas for Category H not exceeding the 10x LCEL, the disposal option is Type 2 – Confine Marine Disposal.

6.4.18 Chemical testing results for the November 2008 sediment survey indicated that heavy metals, particularly Copper (Cu), Zinc (Zn) and Arsenic (As) were high at 2 of the 3 sediment quality sampling locations (SD4 & SD5), where sediments are classified as Category M & H. Sediments found in SD6, near the downstream end, are found to be uncontaminated and hence can be classified as Category L. As there are presence of Category M sediment and Category H sediment with contaminant level exceeding 10x LCEL, biological screening test is necessary. Biological screening test in accordance with ETWB TCW no. 34/2002 is being carried out and is not available for this EIA. The classification of these sediments will be confirmed once results of the biological screening tests are available.

Table 6.2a

Results of the Sediment Testing (January 2008)

Contaminants (mg/kg unless stated otherwise)	Sediment Sample
	SD1	SD2			SD3
	0 – 0.5 m	0 – 0.5 m	2.5 – 3 m	4 – 4.5 m	0 – 0.5 m	4.5 – 5 m	6 – 6.5 m
Cadmium (Cd)	0.26	<0.20	0.79	<0.20	<0.20	<0.20	<0.20
Chromium (Cr)	8.9	14	<8.0	<8.0	12	<8.0	<8.0
Copper (Cu)	58	12	<7.0	<7.0	8.7	<7.0	<7.0
Nickel (Ni)	8.0	9.8	<4.0	<4.0	7.7	<4.0	<4.0
Lead (Pb)	120	29	42	51	24	<8.0	43
Zinc (Zn)	180	76	280	460	59	185	200
Mercury (Hg)	<0.05	0.05	<0.05	<0.05	<0.05	<0.05	<0.05
Arsenic (As)	7.0	12	<1.0	<1.0	7.1	<1.0	4.6
Silver (Ag)	<0.10	<0.10	<0.10	<0.10	<0.10	<0.10	<0.10
LMW PAHs (mg/kg)	<55	<55	<55	<55	<55	<55	<55
HMW PAHs (mg/kg)	<170	<170	<170	<170	<170	<170	<170
Total PCBs (mg/kg)	<3.0	<3.0	<3.0	<3.0	<3.0	<3.0	<3.0
TBT*	<0.015	<0.015	-	-	<0.015	-	-

Notes:

LMW PAHs: low molecular weight polyaromatic hydrocarbon

HMW PAHs: high molecular weight polyaromatic hydrocarbon

PCB: polychlorinated biphenyl

TBT: tributyltin

Values in bold and underlined are the contaminant levels exceeding the Upper Chemical Exceedance Level (UCEL).

* The unit for TBT is mg TBT/L in Interstitial water.

Table 6.2b

Results of the Sediment Testing (November 2008)

Drillhole No.

Sample Depth, m

TBT

From

mg/kg

ug TBT/L

SD4

0.00

0.45

<0.20

120

0.19

<0.10

< 0.015

SD4

0.50

0.95

<0.20

8.4

<7.0

5.2

<0.05

5.3

<0.10

< 0.015

SD4

1.00

1.45

<0.20

<8.0

<7.0

5.0

210

<0.05

4.5

<0.10

< 0.015

SD4

1.50

1.95

0.44

<8.0

<7.0

<4.0

<0.05

2.1

<0.10

< 0.015

SD4

2.00

2.45

<0.20

<8.0

<7.0

<4.0

640

<0.05

<1.0

0.11

< 0.015

SD4

2.50

2.95

<0.20

<8.0

9.2

<4.0

<0.05

<1.0

0.12

< 0.015

SD5

0.00

0.45

0.29

5.1

2400**

<0.05

5.3

<0.10

< 0.015

SD5

0.50

0.95

<0.20

<8.0

6.8

320

<0.05

1.6

1.3

< 0.015

SD5

1.50

1.95

<0.20

<8.0

<7.0

<4.0

<8.0

100

<0.05

<1.0

0.23

< 0.015

SD5

2.50

2.95

<0.20

<8.0

<7.0

<4.0

<8.0

140

<0.05

<1.0

<0.10

< 0.015

SD5

3.50

3.95

<0.20

<8.0

7.6

<4.0

<8.0

180

0.05

<1.0

0.24

< 0.015

SD5

4.00

4.45

<0.20

<8.0

<7.0

<4.0

140

<0.05

<1.0

0.13

< 0.015

SD6

0.00

0.45

0.27

160

0.21

7.2

0.10

< 0.015

SD6

0.50

0.95

0.39

<8.0

<7.0

<4.0

8.2

<0.05

3.1

<0.10

< 0.015

SD6

1.00

1.45

<0.20

<8.0

<7.0

<4.0

9.4

<0.05

<1.0

<0.10

< 0.015

SD6

1.50

1.95

<0.20

<8.0

<7.0

<4.0

<8.0

<20

<0.05

<1.0

<0.10

< 0.015

SD6

2.00

2.45

0.95

<8.0

<7.0

<4.0

8.9

<0.05

1.7

<0.10

< 0.015

SD6

2.50

2.95

<0.20

<8.0

<7.0

<4.0

<0.05

<1.0

<0.10

< 0.015

SD6

3.00

3.45

<0.20

<8.0

<7.0

<4.0

160

<0.05

<1.0

<0.10

< 0.015

SD6

3.50

4.50

<0.20

<8.0

<7.0

<4.0

<0.05

<1.0

0.26

< 0.015

Notes:

1. The bold figure is the contaminant level exceeding the Lower Chemical Exceedance Level (LCEL).

2. The underlined figure is the contaminant level exceeding the Upper Chemical Exceedance Level (UCEL).

3. The figure marked with ** is the contaminant level exceeding 10 times the LCEL.

6.4.19 Under the general allocation conditions by Marine Fill Committee (MFC) of CEDD, the following information should be submitted to the relevant authorities once they are available.

General Allocation Conditions for Type 1 – Open Sea Disposal

6.4.20 Prior to the commencement of dumping the Engineer shall submit to the Director of Environmental Protection and the Secretary MFC, an estimated programme for the dumping of mud at the mud disposal site(s) during the contract. This programme shall be resubmitted whenever significant programme changes occur.

6.4.21 The Contractor shall submit, through the Engineer, to the Director of Environmental Protection and the Secretary MFC, monthly returns showing the volumes of sediments dumped at the mud disposal site(s) in the previous month together with an estimation of the volumes to be dumped in the following month.

General Allocation Conditions for Type 2 – Confined Marine Disposal

6.4.22 The Contractor shall submit to the Director of Environmental Protection, a method statement covering the disposal of contaminated mud and this method must be approved before a licence for marine dumping can be issued.

6.4.23 At least one week prior to commencement of the excavation works, the Engineer shall submit to the Secretary MFC a programme of work showing the volume of contaminated sediment to be excavated per month during the term of the contract. Thereafter, on a monthly basis, the Engineer shall submit a revised programme taking into account the volume disposed of during the preceding month.

Dumping Permit

6.4.24 The Contractor shall make a formal application to EPD for a dumping permit under the Dumping at Sea Ordinance (DASO) (Cap.466). If the permit is granted, the Contractor shall ensure the permit conditions are met to the satisfaction of EPD.

Mitigation Measures

6.4.25 Excavation of contaminated sediments is of particular concern. The Contractor should implement the proposed water quality mitigation measures (see Chapter 5) to prevent inadvertent release of contaminated sediment or runoff to the surrounding water bodies during excavation.

Chemical Waste

6.4.26 Wastes classified as chemical waste are listed in the Waste Disposal (Chemical Waste) (General) Regulation. Where the construction processes produce chemical waste, the Contractor must register with EPD as a chemical waste producer. In general, chemical waste would mainly arise from maintenance of construction equipment. These may include the following items:

· scrap batteries or spent acid/alkali from their maintenance;

· used engine oils, hydraulic fluids and waste fuel;

· spent mineral oils/cleaning fluids from mechanical machinery; and

· spent solvents/solutions from equipment cleaning activities.

6.4.27 Chemical wastes pose serious environmental and health and safety hazards if not stored and disposed of in an appropriate manner as outlined in the Chemical Waste Regulation. These hazards include:

· toxic effects to works;

· adverse effects on water quality from spills; and

· fire hazards.

6.4.28 The amount of chemical waste cannot be accurately predicted at this stage since it largely depends on the Contractor’s housekeeping measure. The amount is anticipated to be small and it is recommended that the Contractors should implement good housekeeping measures to minimise the amount of chemical waste generated.

General Works Waste

6.4.29 The following wastes will be generated during general construction activities:

· concrete waste;

· wooden materials; and

· municipal waste.

Concrete Waste

6.4.30 Of the volume of concrete supplied, it is expected that only a very small percentage of the concrete used will be lost to waste.

Wooden Materials

6.4.31 Different kinds of wooden materials are essential to the construction project, such as wooden boards used as falsework and formwork for concrete structures, erection of site boundaries, as well as bamboo for scaffolding. Wooden materials are important and valuable resources.

6.4.32 Site fencing may be necessary to separate the construction works from the public and to reduce construction nuisance such as noise to nearby sensitive receivers. In this case metal fencing or building panels to provide site fencing should be used. Attention should be paid to WBTC No. 19/2001 – “Metallic Site Hoardings and Signboards” to reduce the amount of timber used on construction sites.

Municipal Waste

6.4.33 Municipal waste will be generated by the site staff and construction workers during the construction period. This includes food scraps, papers, plastic containers, packaging materials, etc. The amount of municipal waste that may be produced is dependent on size of workforce at site.

6.4.34 The storage of general refuse has the potential to give rise to a variety of adverse environmental impacts. These include odour if putrescible food waste is not collected frequently, water quality impacts if waste enters water bodies and visual impact from windblown litters. The refuse may attract pests and vermin if the storage areas are not well maintained and cleaned regularly. In addition, disposal of waste at sites other than approved waste transfer or disposal facilities can also lead to environmental impacts.

6.4.35 Handling and disposal of general refuse should cope with the presence of peak workforce during the construction period. Provided that the refuse is stored and transported in accordance with proper practices and disposed at approved disposal facilities, potential environmental impact is not expected.

6.4.36 A summary of the main C&D materials and wastes expected to arise from the Project and the estimated quantities for each type of C&D materials is presented in Tables 6.3 and 6.4 respectively.

Table 6.3

Types of C&D Materials and Wastes Generated by the Proposed Project

Area	Major Activities	Waste Type
Temporary and permanent works area	Site clearance and demolition of structures	Vegetation, garbage, topsoil, concrete and other inert materials
Permanent works area not part of existing streams	Excavation	Soil, rock and other inert materials
Permanent works area that are part of existing streams	Excavation	Soil, rock and other inert materials Sediment
All	Construction of channel structures / general site activities	Chemical waste, concrete waste, scrap metal, wood and other non-inert waste

Table 6.4

Summary of the Quantities of Sediment, C&D Materials and Wastes Arising from the Proposed Project

*Estimated Quantities (m³)**
Sediment (see Note 1)	Inert C&D Material (soft public fill) (see Note 2)	Rock (Grade III or below)	C&D Waste	Chemical Waste	General Works Waste	Total
2,900	6,270	0	420	Minimum amount (see Note 3)	Minimum amount (see Note 4)	9,590
Approximate timing* : end 2009 – end 2012

Notes:

* Tentative construction programme of end 2009 – end 2012 may be subject to further changes. The estimated quantities are based on preliminary design of the proposed channel works and the best available ground investigation data. The waste arising will largely depend on the contractor works programme and activities. The contractor will be required to provide detailed estimation of all the C&D materials and waste generated on-site using a Monthly / Yearly Waste Flow Table as required under ETWB TCW No. 19/2005.

1 Uncontaminated sediment should be reused within the Project. Contaminated sediment should be disposed to location as allocated by the MFC. Contaminated sediment should be handled and disposed according to the dumping permit conditions under the DASO. Dumping permit should be obtained by the Contractor.

2 Topsoil and suitable materials should be stockpiled for later reuse in this or other projects subject to approval by relevant parties in accordance with the ETWB TCW No. 31/2004. The amount of materials that can be reused in this Project will be examined further during the detailed design stage.

3 The amount of chemical waste will be dependent on the contractor’s on-site maintenance programme and the number of equipment and vehicles used on-site. Chemical waste should be collected by licensed contractor and properly disposed of at approved chemical waste treatment facilities (e.g. the Chemical Waste Treatment Centre at Tsing Yi). Chemical waste will be generated throughout the construction period.

4 The amount of general works waste will depend on the contractor’s operating procedures and housekeeping practices as well as the size of the workforce on-site. All such wastes should be sorted, reused and recycled before disposal at designated outlets. General works waste will be generated throughout the construction period.

6.4.37 Out of the total 6,700 m³ C&D materials generated, almost 90% of the C&D materials (6,000 m³) generated will be reuse on-site. It is estimated that the quantity of C&D materials (excluding sediment) to be transported off site is about 700 m³. Only about 4% of the C&D materials (280 m³) that may be unsuitable for reuse will be disposed of at designated public fill reception facilities. The remaining 6% of these materials (420 m³) will be C&D waste which will be disposed of to designated landfill.

6.4.38 As the Project has a shortfall of fill material, importation of soft fill and rock is required. The amount of soft public fill and rock that needs to be imported is about 12,130 m³ and 1,000 m³ respectively.

6.5 Mitigation Measures

General

6.5.1 The HKSAR Government's construction and demolition waste management policy follows the same hierarchy as for other wastes, i.e. in order of desirability: avoidance, minimisation, recycling, treatment and safe disposal of waste. During the construction period the Contractor, Engineer and environmental specialists (Environmental Team, Independent Environmental Check) should work closely together with a view to reduce the volumes of materials requiring removal and final disposal.

6.5.2 Upon appointment, the main Contractor of each construction contract should prepare and implement an Environmental Management Plan (EMP) in accordance with ETWB TCW No. 19/2005 – “Environmental Management on Construction Sites” which should describe the arrangements for avoidance, reuse, recovery, recycling, storage, collection, treatment and disposal of different categories of waste to be generated from the construction activities. The EMP should incorporate site specific factors, such as the designation of areas for segregation and temporary storage of reusable and recyclable materials. The EMP should be submitted to the Engineer for approval. The Contractor should implement the waste management practices in the EMP throughout the construction stage of the Project. The EMP should be reviewed regularly and updated (preferably monthly) by the Contractor. The EMP should take into account the recommended mitigation measures in the approved EIA Report.

6.5.3 The Contractor should refer to the simplified Construction and Demolition Material Management Plan (C&DMMP) conducted for this Project (Appendix 6.2) to facilitate him in the preparation of the EMP. The simplified C&DMMP has been endorsed by CEDD’s Vetting Committee and approved by the Public Fill Committee (PFC). CEDD’s Vetting Committee will monitor the implementation of the C&DMMP and report to Public Fill Committee in accordance with ETWB TCW No. 33/2002 during construction.

6.5.4 Training of construction staff should be undertaken by the Contractor about the concept of site cleanliness and appropriate waste management procedures. The Contractor should develop and provide toolbox talk for on-site sorting of C&D materials to enhance worker’s awareness in handling, sorting, reuse and recycling of C&D materials. Requirements for staff training should be included in the EMP.

6.5.5 Good planning and site management practice should be employed to eliminate over ordering or mixing of construction materials to reduce wastage. Proper storage and site practices will minimise the damage or contamination of construction materials. Regular cleaning and maintenance of the waste storage area should be provided.

6.5.6 Where waste generation is unavoidable, the potential for recycling or reuse should be rigorously explored. If waste cannot be recycled, disposal routes described in the EMP should be followed. A recording system for the amount of wastes generated, recycled and disposed (including the disposal sites) should be implemented. In order to monitor the disposal of C&D material and solid wastes at public fill reception facilities and landfills and to control fly-tipping, a trip-ticket system should be included. One may make reference to ETWB TCW No. 31/2004 for details.

6.5.7 Imported soft fill and rocks should be source from CEDD’s fill bank, other projects or other approved sources instead of using new materials. Approval from the Engineer and all other relevant parties should be obtained by the Contractor before importation of the fill materials.

On-site Sorting, Reuse and Recycling

6.5.8 All waste materials should be segregated into categories covering:

· excavated materials suitable for reuse on-site;

· excavated materials suitable for public filling facilities;

· remaining C&D waste for landfill;

· chemical waste; and

· general refuse for landfill.

6.5.9 Proper segregation and disposal of construction waste should be implemented. Separate containers should be provided for inert and non-inert wastes.

6.5.10 Sorting is important to recover materials for reuse and recycling. Specific area should be allocated for on-site sorting of C&D materials and to provide a temporary storage area for those sorted materials such as metals, concrete, timber, plastics, glass, excavated spoils, bricks / tiles and waste papers. If area is limited, all C&D materials should at least be sorted on-site into inert and non-inert components. Non-inert materials (C&D waste) such as bamboo, timber, vegetation, packaging waste and other organic materials should be reused and recycled wherever possible and disposed of to designated landfill only as a last resort. Inert materials (public fill) such as concrete, stone, clay, brick, soil, asphalt and the like should be separated and reused in this or other projects (subject to approval by the relevant parties in accordance with the ETWB TCW No. 31/2004) before disposed of at a public fill reception facility operated by Civil Engineering and Development Department (CEDD). Steel and other metals should be recovered from demolition waste stream and recycled.

6.5.11 The reuse of inert materials such as soil, rock and broken concrete should be maximised. Waste should be separated into fine, soft and hard materials. With the use of a crusher coarse material can be crushed to make it suitable for use as fill material where fill is required in the works. This minimises the use of imported material and maximises use of the C&D material produced.

6.5.12 Prior to export of material from the site, the potential for it to be reused should be assessed. Most C&D material can easily be reused with minimum processing. Waste separation methods should be followed to ensure that C&D waste is separated at source. Suitable soft materials should be used for landscaping and grading of embankments. Fine material should be separated out and used as topsoil.

6.5.13 The feasibility of using recycled aggregates in lieu of virgin materials should be rigorously considered during the detailed design and construction phases as stipulated in WBTC No. 12/2002 and ETWB TCW No. 24/2004. In general, recycled aggregates are suitable for use as fill materials in earthworks, road sub-base formation, and drainage works. Recycled aggregates can also be used in concrete (up to Grade 35) for mass concrete walls and other minor structures such as planter boxes, toe wall planters and pavement, etc.

6.5.14 Recycled inert C&D material should be used in the works as sub-bases for access roads and footpaths of the proposed channel. Recycled aggregates should be considered for use in concrete as outlined in the above mentioned technical circulars. Some recycled rock material can be reused as rock fill or as stream bed material. This is dependent on size of rock fragments but can be achieved by appropriate use of a crusher.

Site Clearance / Demolition Materials

Excavated Materials

6.5.15 All C&D materials should be sorted on-site into inert and non-inert components by the Contractor. Non inert materials (C&D waste) such as wood, glass and plastic should be reused and recycled before disposal to a designated landfill as a last resort (currently assume to be the WENT Landfill). Inert materials (public fill) such as soil, rubble, sand, rock, brick and concrete should be separated and where appropriate broken down to size suitable for subsequent filling. Suitable C&D material should be use as pipe bedding or for backfilling of retaining walls, box culvert and formation of channel embankments. Excavated rocks from existing streams should be reused for rip-rap lining. Inert materials should be reused on-site or in other projects approved by relevant parties in accordance with the ETWB TCW No. 31/2004 before disposed of at public fill reception facilities. Steel and other metals should be recovered from C&D materials and recycled.

6.5.16 Some of the excavated sediment from the stream bed will be contaminated with high levels of heavy metals. Contaminated sediment should be disposed to marine disposal in accordance with ETWB TCW No. 34/2002 and WBTC No. 12/2000. In order to minimise off-site disposal, uncontaminated sediment should be reused as channel bed material as far as possible.

6.5.17 Good quality reusable topsoil should be stockpiled for later landscaping works. Stockpiles should be less than 2 m in height, formed to a safe angle of repose and hydroseeded or covered with tarpaulin to prevent erosion during the rainy season and to minimise dust generation.

6.5.18 Control measures for temporary stockpiles on-site should be taken in order to minimize the noise, generation of dust, pollution of water and visual impact. These measures include:

· surface of stockpiled soil should be regularly wetted with water especially during dry season;

· disturbance of stockpiled soil should be minimized;

· stockpiled soil should be properly covered with tarpaulin especially when heavy rain storms are predicted;

· stockpiling areas should be enclosed where space is available;

· stockpiling location should be away from the water bodies; and

· an independent surface water drainage system equipped with silt traps should be installed at the stockpiling area.

6.5.19 The identification of final disposal sites for C&D materials generated by the construction works will be considered during the detailed design stage of the Project when the volume and types of C&D materials can be more accurately estimated. The Public Fill Committee of CEDD should be consulted on designated outlets (e.g. public fill reception facility) for public fill, whilst EPD should be consulted on landfills for C&D waste. Marine Fill Committee of CEDD should be consulted on the marine disposal sites of the excavated sediment if needed. The public fill to be disposed to public fill reception facilities must consist entirely of inert construction materials. Disposal of C&D waste to landfill must not have more than 50% (by weight) inert material. The C&D waste delivered for landfill disposal should contain no free water and the liquid content should not exceed 70% by weight.

6.5.20 In order to avoid dust or odour impacts, any vehicles leaving a works area carrying C&D waste or public fill should have their load covered up before leaving the construction site.

6.5.21 C&D materials should be disposed of at designated public fill reception facilities or landfills. Reuse of public fill materials at other construction projects is subject to the approval of the relevant project proponents, Engineer and/or other relevant authorities, such as LandsD, PlanD, etc. Furthermore, unauthorized disposal of C&D materials in particular on private agricultural land is prohibited and may be subject to relevant enforcement and regulating actions. The Contractor shall refer and strictly follow the trip-ticket system for the disposal of C&D materials as stipulated in the ETWB TCW No. 31/2004.

Chemical Waste

6.5.22 Where the construction processes produce chemical waste, the Contractor must register with EPD as a chemical waste producer. Wastes classified as chemical wastes are listed in the Waste Disposal (Chemical Waste) (General) Regulation. These wastes are subject to stringent disposal routes. EPD requires information on the particulars of the waste generation processes including the types of waste produced, their location, quantities and generation rates. A nominated contact person must be registered with EPD. An updated list of licensed chemical waste collector can be obtained from EPD.

6.5.23 Storage, handling, transport and disposal of chemical waste should be arranged in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes published by EPD, and should be collected by a licensed chemical waste collector.

6.5.24 Suitable containers should be used for specific types of chemical wastes, containers should be properly labelled (English and Chinese in accordance with instructions prescribed in Schedule 2 of the Regulations), resistance to corrosion, safely stored and securely closed. Stored volume should not be kept more than 450 liters unless the specification has been approved by the EPD. Storage area should be enclosed by three sides by a wall, partition of fence that is at least 2 m height or height of tallest container with adequate ventilation and space.

6.5.25 Hard standing, impermeable surfaces draining via oil interceptors should be provided in works area compounds. Interceptors should be regularly emptied to prevent release of oils and grease into the surface water drainage system after accidental spillages. The interceptor should have a bypass to prevent flushing during periods of heavy rain. Oil and fuel bunkers should be bunded and/or enclosed on three sides to prevent discharge due to accidental spillages or breaches of tanks. Bunding should be of sufficient capacity to accommodate 110% of the volume of the largest container or 20% of the total volume of waste, whichever is largest. Waste collected from any grease traps should be collected and disposed of by a licensed contractor.

6.5.26 Lubricants, waste oils and other chemical wastes are likely to be generated during the maintenance of vehicles and mechanical equipment. Used lubricants should be collected and stored in individual containers which are fully labelled in English and Chinese and stored in a designated secure place. If possible, such waste should be sent to oil recycling companies, and the empty oil drums collected by appropriate companies for reuse or refill.

6.5.27 The registered chemical waste producer (i.e. the contractor) has to arrange for the chemical waste to be collected by licensed collectors. The licensed collector should regularly take chemical waste to a licensed chemical waste treatment facility (such as the Chemical Waste Treatment Centre in Tsing Yi). A trip ticket system operates to control the movement of chemical wastes.

6.5.28 No lubricants, oils, solvents or paint products should be allowed to discharge into water courses, either by direct discharge, or as contaminants carried in surface water runoff from the construction site.

General Works Waste

Concrete Waste

6.5.29 Dry concrete waste (considered as public fill) should be sorted out from the other wastes and recycled for reuse or sorted out for disposal at designated public fill reception facilities.

Wooden Materials

6.5.30 All wooden materials used on-site should be kept separate from other wastes to avoid damage and to facilitate reuse. Timber which cannot be reused should be sorted out from other waste and stored separately from all inert waste before being disposed of to landfill.

6.5.31 Reusable steel or concrete panel shutters, fencing and hoarding and signboard should be used as a preferred alternative to items made of wood, to minimise wastage of wood. Attention should be paid to WBTC No. 19/2001 – “Metallic Site Hoardings and Signboards” to reduce the amount of timber used on construction sites. Metallic alternatives to timber are readily available and should be used rather than new timber. Precast concrete units should be adopted wherever feasible to minimize the use of timber formwork.

6.5.32 Only waste material need to be taken to a landfill. It should be separated from recyclable wood and steel materials. As for all waste types these materials should be reused on-site or other approved sites before disposal is considered as an option. Disposal to landfill should only be considered as a final option. Contractors are responsible for storage of re-useable materials on-site.

Municipal Waste

6.5.33 General refuse generated on-site should be stored in enclosed bins or skips and collected separately from other construction and chemical wastes and disposed of at designated landfill. A temporary refuse collection point should be set up by the Contractor to facilitate the collection of refuse by licensed contractors. The removal of waste from the site should be arranged on a daily or at least on every second day by the Contractor to minimise any potential odour impacts, minimise the presence of pests, vermin and other scavengers and prevent unsightly accumulation of waste.

6.5.34 The recyclable component of the municipal waste generated by the workforce, such as aluminium cans, paper and cleansed plastic containers should be separated from other waste. Provision and collection of recycling bins for different types of recyclable waste should be set up by the Contractor. The contractor should also be responsible for arranging recycling companies to collect these materials.

6.5.35 The burning of refuse on-site is prohibited under the Air Pollution Control Ordinance (APCO) (Cap.311).

6.5.36 A summary of the estimated C&D materials and waste and their disposal routes are tabulated in Table 6.5. The preliminary disposal programme breakdown is shown in Table 6.6.

Table 6.5

Summary of the Quantities and Disposal Routes of C&D Materials and Waste Arising from the Project

C&D Materials and Waste Types

Estimated Quantities*

Disposal Routes (see note 5)

Site Clearance / Demolition Materials

- Public fill

- C&D waste

630 m³ (see note 1)

- 270 m³

- 360 m³

Public Fill
Sort out recyclable materials, suitable material reuse on site or reuse at other approved projects, dispose to designated Public Fill Reception Facilities (e.g. Fill Bank at Tuen Mun Area 38 or Tseung Kwan O Area 137).

C&D waste
Sort out recyclable materials before disposal at designated landfill (e.g. WENT Landfill).

Excavated Materials

- Contaminated sediment

- Uncontaminated sediment

- Public fill

- C&D waste

8,960 m³ (see note 2)

- 1,000 m³

- 1,900 m³

- 6,000 m³

- 60 m³

Sediment
Contaminated – marine disposal sites subject to allocation by relevant authority.

Uncontaminated – to be reuse on-site as channel bed material.

C&D waste
Sort out recyclable materials before disposal at designated landfill (e.g. WENT Landfill).

Chemical Waste

Minimum amount (see note 3)

Recycle, dispose to approved chemical waste treatment facilities.

General Works Waste

- Concrete waste

- Wooden waste

- Municipal waste

Minimum amount (see note 4)

Concrete waste
Sort and recycle/reuse on site, recycle/reuse at other approved projects, dispose to designated Public Filling Facilities (e.g. Fill Bank at Tuen Mun Area 38 or Tseung Kwan O Area 137).

Wooden waste
Sort and reuse on site, reuse at other approved projects, dispose to designated landfill (e.g. WENT Landfill).

Municipal waste
Sort out recyclable materials (e.g. paper, plastic, aluminium can), dispose to designated landfill (e.g. WENT Landfill).

Notes:

* The estimated quantities are based on the preliminary design of the proposed channel works and the best available ground investigation data. The waste arising will largely depends on the contractor works programme and activities. The contractor will be required to provide detailed estimation of all the C&D materials and waste generated on-site using a Monthly / Yearly Waste Flow Table as required under ETWB TCW No. 19/2005.

1 From clearance of vegetation, demolition of hard paved slab, temporary structures and squatter houses.

2 Topsoil and suitable materials including sediment will be stockpiled for later reuse in this or other projects subject to approval by the relevant parties in accordance with ETWB TCW No. 31/2004. The amount of materials that can be reuse in this Project will be examined further during the detailed design and construction phases.

4 The amount of general works waste will depend on the contractor’s operating procedures and housekeeping practices as well as the size of the workforce on-site. All such wastes will be sorted, reused and recycled before disposal at designated outlets.

5 All suitable materials will be reuse and recycle before disposal. Reuse of C&D materials at other projects is subject to approval by the relevant parties in accordance with ETWB TCW No. 31/2004. Final disposal outlets subject to final agreement with Marine Fill Committee of CEDD or EPD for marine dumping grounds, Public Fill Committee of CEDD for public fill reception facilities and EPD for landfills.

Table 6.6

Preliminary Disposal Programme of the C&D Materials

Reuse / Disposal Arrangement	Approximate Quantity of C&D materials (m³)
*2010*
Reuse	1,700
Disposal of to public fill reception facilities	170
Disposal of to landfill	360
Reuse or marine disposal (sediment)	1,400
*2011*
Reuse	4,300
Disposal of to public fill reception facilities	100
Disposal of to landfill	60
Reuse or marine disposal (sediment)	1,500
2012*
Reuse	0
Disposal of to public fill reception facilities	0
Disposal of to landfill	0
Reuse or marine disposal (sediment)	0

Notes:

* As the major construction works will be substantially completely by then, the amount of C&D material generated is expected to be minimal. This will be confirmed by the Contractor.

The exact programme and quantities of the disposal works will depend on the Contractor’s programme after the contracts are awarded.

6.6 Operational Waste

6.6.1 The operation of the proposed access road and viewing point and carpark will not generate excessive waste. It is expected that only a very small amount of general litter will be accumulated on the road surface which when left unhandled may be flushed out to Deep Bay via the road drainage system during rainstorms.

6.6.2 Adequate litter bins should be provided at the viewing point and carpark and should be regularly emptied by Food and Environmental Hygiene Department (FEHD). Normal road sweeping and street cleansing routinely carried out by FEHD on a need basis is considered adequate to minimise impact from such waste. Road side gullies should be cleared and desilted regularly to ensure proper operation of the road drainage system.

6.6.3 Maintenance would be necessary for the constructed channel to remove excessive silts, vegetation, debris and obstructions in order to maintain its hydraulic performance and structural integrity. Siltation will generally be allowed to accumulate and removal of excess silt would be carried out at locations where specific flooding or safety issue is identified. Little or no maintenance will be necessary for the natural stream bed sections of the channel.

6.6.4 As such, the quantity of the silt and vegetation removed from annual maintenance is expected to be limited, no adverse impact is expected during the operational phase of the Project (in terms of maintenance of the channel).

6.6.5 Nonetheless, proper waste management procedures should be implemented. In general, desilting or maintenance works should be carried out during dry season where flow in the watercourse is low. Non-inert materials such as excess vegetation and garbage should be properly packed and disposed of to landfill. Inert material such as excess silt should be dried and disposed of public fill reception facilities or to landfill if the amount is negligible. The locations for the disposal of the above materials should be identified and agreement sought with the relevant departments before commencement of the maintenance works.

6.7 Evaluation of Residual Impacts

6.7.1 With the implementation of proper waste management practices for storage, handling, transportation and disposal of waste arisings, no residual impacts are expected during the construction and operational phases of the Project.

6.8 Environmental Audit

6.8.1 Auditing should be carried out periodically to determine if waste is being managed in accordance with prescribed waste management procedures and the EMP. The audits should examine all aspects of waste management including waste generation, storage, recycling, treatment, transportation, and disposal. The general site inspections including waste management issues will be undertaken weekly by the Environmental Team to check all construction activities for compliance with all appropriate environmental protection and pollution control measures, including those set up in the EMP. Meanwhile, waste management audit will also be carried out as part of the monthly audit by the Independent Environmental Checker.

6.9 Summary

6.9.1 Construction and demolition materials will inevitably be produced during the construction phase of the Project. Waste generated during construction works includes site clearance / demolition materials, excavated materials, chemical waste and general works waste. Waste types, quantities and timing have been estimated and mitigation measures have been proposed in terms of the avoidance-minimisation-reuse-recycling-disposal hierarchy.

6.9.2 Potential for reuse of inert construction & demolition material (public fill) within the Project will be rigorously explored throughout the course of the Project in an effort to minimise off-site disposal.

6.9.3 A small quantity of contaminated stream sediment will be excavated and need to be disposed offsite in designated marine disposal sites. Potential for reuse of uncontaminated sediment as channel bed material will be maximized as far as practicable. Provided that there is strict control of construction and demolition materials generated from construction works and that all arisings are stored, handled, transported and disposed of in accordance with the recommended mitigation measures, potential impact is not expected. The recommended mitigation measures can be enforced by incorporating them into the waste management requirements as part of the Environmental Management Plan. Environmental audit would be necessary to ensure the implementation of proper waste management practices during construction.

6.9.4 Waste generated during operation and maintenance is expected to be minimal. Proper waste management practices have been recommended.