7                    WASTE MANAGEMENT IMPLICATIONS

 

7.1              Introduction

 

This section identifies the potential wastes arising from the construction and operation of the Proposed Beach Developing at Lung Mei and assesses the potential environmental impacts associated with waste handling and disposal.  The main issues are:

 

·     Management of dredged materials;

 

·     Handling and disposal of contaminated soil/sediments;

 

·     Handling and disposal of construction and demolition (C&D) materials arising from the demolition, excavation and construction works; and

 

·     Management of chemical waste, sewage, and general refuse.

 

Waste avoidance, minimisation, reuse and recycling, storage, collection, transport and disposal schemes have been examined and appropriate measures for waste reduction and management have been proposed. 

 

7.2              Relevant Legislation and Guidelines

 

The following discussion on legislative requirements and evaluation criteria applies to both the construction and operational phases of the Proposed Beach Development.  The criteria and guidelines for evaluating potential waste management implications are laid out in Annexes 7 and 15 of the EIAO-TM under the EIAO (Cap 499). The following legislation covers, or has some bearing upon the handling, treatment and disposal of the wastes generated from the construction and operation of the Proposed Beach Development.

 

·     Waste Disposal Ordinance (Cap 354);

 

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

 

·     Land (Miscellaneous Provisions) Ordinance (Cap 28)

 

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

 

·     Dumping at Sea Ordinance (Cap 466).

 

7.2.1        Waste Disposal Ordinance (Cap 354)

 

The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes, with waste defined as any substance or article, which is abandoned.  Construction waste is not directly defined in the WDO but is considered to fall within the category of ‘trade waste’.  Trade waste is defined as waste from any trade, manufacturer or business or any wasted building, or civil engineering materials, but does not include animal waste.

 

Under the WDO, wastes can only be disposed of at a licensed site.  The WDO provides for the issuing of licences for the collection and transport of wastes.  Licences are not, however, currently issued for the collection and transport of construction waste or trade waste.

 

The Waste Disposal (Charges for Disposal of Construction Waste) Regulation defined construction waste as any substance, matters or things that is generated from construction work and abandoned, whether or not it has been processed or stockpiled before being abandoned.   

 

The Construction Waste Disposal Charging Scheme entered into operation on 1 December 2005.  Starting from 1 December 2005, the main contractor who undertakes construction work under a contract with value of HK$1 million or above is required to open a billing account solely for the contract for waste disposal.  Application shall be made within 21 days after the contract is awarded.  Under the Scheme, charging for disposal of construction waste started on 20 January 2006 and therefore will apply to this Project. 

 

Depending on the percentage of inert materials in the construction waste, inert construction waste can be disposed of at public fill reception facilities.  However mixed construction waste can be disposed of at construction waste sorting facilities and landfills which have different disposal costs.  The scheme encourages reducing, reusing and sorting of construction waste such that the waste producer can reduce their disposal fee.  Table 7.1 summarises the government construction waste disposal facilities, types of waste accepted and disposal cost.

 

Table 7.1: Government Facilities for Disposal of C&D Materials

Government Waste Disposal Facilities	Type of Construction Waste Accepted	Charge (HK$/Tonne)
Public fill reception facilities	Consisting entirely of inert construction waste	$27
Sorting facilities	Containing more than 50% by weight of inert construction waste	$100
Landfills	Containing not more than 50% by weight of inert construction waste	$125
Outlying Islands Transfer Facilities	Containing any percentage of inert construction waste	$125

 

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

 

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

 

A person should not produce, or cause to be produced, chemical wastes without registration with the EPD.  Chemical wastes must either be treated using on-site facility licensed by EPD or be collected by a licensed collector for off-site treatment at a licensed facility.  Under EPD Regulation, the waste producer, collector and disposal facility must sign all relevant parts of a computerised trip ticket for each consignment of waste.  The computerized system is designed to allow the transfer of wastes to be traced from cradle-to-grave.

 

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

 

7.2.3        Land (Miscellaneous Provisions) Ordinance (Cap 28)

 

The inert portion of C&D materials (also called public fill) may be taken to public fill reception facilities.  Public filling areas usually form part of land reclamation schemes and are operated by the Civil Engineering and Development Department (CEDD) and others.  The Land (Miscellaneous Provisions) Ordinance requires that individuals or companies who deliver public fill to the public fill reception facilities to obtain a Dumping Licence from the CEDD. 

Under the licence conditions, public fill reception facilities will only accept earth, soil, sand, rubble, brick, tile, rock, boulder, concrete, asphalt, masonry or used bentonite.  In addition, in accordance with paragraph 11 of the ETWB TC(W) No.31.2004, Public Fill Committee will advise on the acceptance criteria (e.g. no mixing of construction waste, nominal size of the materials less than 250mm, etc).  The material should, however, be free from marine mud, household refuse, plastic, metal, industrial and chemical wastes, animal and vegetable matter and any other materials considered unsuitable by the public fill reception facility supervisor.

 

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

 

This Regulation provides a further control on the illegal dumping of wastes on unauthorised (unlicensed) sites. 

 

7.2.5        Dumping at Sea Ordinance (Cap 466)

 

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

 

·       Type and quantity of substances permitted to be dumped; 

 

·       Location of the disposal grounds; 

 

·       Requirement of equipment for monitoring the disposal operations; and

 

·       Environmental monitoring requirements.

 

Management of Dredged/Excavated Sediments for Marine Disposal

 

Marine disposal of any dredged/excavated sediment is subject to control under the Dumping at Sea Ordinance 1995.  Dredged/excavated sediment destined for marine disposal is classified based on its contaminant levels with reference to the Chemical Exceedance Levels (CEL), as stipulated in ETWBTC No. 34/2002: Management of Dredged/Excavated Sediment.  This Technical Circular includes a set of sediment quality criteria, as presented in Table 7.2, which includes heavy metals and metalloids, organic pollutants and a class of contamination level for highly contaminated sediment not suitable for marine disposal.

Table 7.2: Dredged/Excavated Sediment Quality Criteria for the Classification under the ETWBTC No 34/2002

Contaminants	Lower Chemical Exceedance Level (LCEL)	Upper Chemical Exceedance Level (UCEL)
Metals (mg kg-1 dry weight)
Cd	1.5	4
Cr	80	160
Cu	65	110
Hg	0.5	1
Ni(a)	40	40
Pb	75	110
Silver (Ag)	1	2
Zinc (Zn)	200	270
Metalloid (mg kg-1 dry weight)
Arsenic (As)	12	42
Organic-PAHs (mg kg-1 dry weight)
Low Molecular Weight (LMW) PAHs	550	3,160
High Molecular Weight (HMW) PAHs	1,700	9,600
Organic-non-PAHs (mg kg-1 dry weight)
Total PCBs	23	180
Organometallics (mgTBT l-1  in interstitial water)
Tributyl-tin (a)	0.15	0.15
Note: (a)        The contaminant level is considered to have exceeded the UCEL if it is greater than the value shown.

 

In accordance with ETWBTC 34/2002, the sediment is classified into three categories based on its contamination levels:

 

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

 

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

 

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

 

Figure 7.2 summarises the sediment classification and disposal arrangements.  EPD will use the sediment and biological test results to determine the most appropriate disposal site (e.g. open sea or confined marine disposal site).

 

In accordance with ETWB TC 34/2002, the allocation of sediment disposal space at sea will be considered only if the need for removal of the sediment has been satisfactorily demonstrated.  Therefore it is desirable to demonstrate that any proposed mud dredging has been reduced as far as reasonably and safely practicable and to obtain, in-principle, an agreement from the Secretary of the Marine Fill Committee (MFC) of the CEDD at an early stage.  Procedures as stipulated under ETWB TCW No. 34/2002 should be followed if marine disposal of dredged/ excavated sediments is involved.

 

7.2.6        Other Relevant Guidelines

 

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

 

·     Waste Disposal Plan for Hong Kong (December 1989), Planning, Environment and Lands Branch Government Secretariat, Hong Kong Government;

 

·     Chapter 9 - Environment (1999), Hong Kong Planning Standards and Guidelines, Hong Kong Government;

 

·     New Disposal Arrangements for Construction Waste (1992), EPD & CED, Hong Kong Government;

 

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

 

·     Works Branch Technical Circular (WBTC) No. 32/92, The Use of Tropical Hard Wood on Construction Site; Works Branch, Hong Kong Government; 

 

·     WBTC No. 2/93, Public Dumps. Works Branch, Hong Kong Government; 

 

·     WBTC No. 2/93B, Public Filling Facilities, Works Branch, Hong Kong Government;

 

·     WBTC No. 16/96, Wet Soil in Public Dumps; Works Branch, Hong Kong Government;  

 

·     WBTC Nos. 4/98 and 4/98A, Use of Public Fill in Reclamation and Earth Filling Projects; Works Bureau, Hong Kong SAR Government; 

 

·     Waste Reduction Framework Plan, 1998 to 2007, Planning, Environment and Lands Bureau, Government Secretariat, 5 November 1998;

 

·     WBTC Nos. 25/99, 25/99A and 25/99C, Incorporation of Information on Construction and Demolition Material Management in Public Works Sub-committee Papers; Works      Bureau, Hong Kong SAR Government;

 

·     WBTC No. 12/2000, Fill Management; Works Bureau, Hong Kong SAR Government;

 

·     WBTC No. 19/2001, Metallic Site Hoardings and Signboards; Works Bureau, Hong Kong SAR Government; 

 

·     WBTC Nos. 6/2002 and 6/2002A, Enhanced Specification for Site Cleanliness and Tidiness. Works Bureau, Hong Kong SAR Government; 

 

·     WBTC No. 11/2002, Control of Site Crusher. Works Bureau, Hong Kong SAR Government;

 

·     WBTC No. 12/2002, Specification Facilitating the Use of Recycled Aggregates. Works Bureau, Hong Kong SAR Government;

 

·     ETWBTC No. 33/2002, Management of Construction and Demolition Material Including Rock; Environment, Transport and Works Bureau, Hong Kong SAR Government;

  

·     EWBTC No. 34/2002, Management of Dredged/Excavated Sediment; Environment, Transport and Works Bureau, Hong Kong SAR Government; 

 

·     ETWBTC No. 31/2004, Trip Ticket System for Disposal of Construction & Demolition Materials, Environment, Transport and Works Bureau, Hong Kong SAR Government; and

 

·     ETWBTC No. 19/2005, Environmental Management of Construction Site, Environment, Transport and Works Bureau, Hong Kong SAR Government.

 

7.3              Expected Waste Sources

 

7.3.1        Construction Phase

 

During the construction phase, the main activities, which will result in generation of waste, include dredging and excavation, road widening, culvert diversion and construction and building works.  The Proposed Beach Development was designed to minimize waste generation and promote reuse and recycling of any waste generated from the construction.  Waste avoidance and minimisation will be considered during the planning and design stages and in the selection of options for construction methods and programme. 

 

The typical waste types associated with these activities include:

 

·      Dredged marine sediment;

·      C&D materials;

·      Chemical waste;

·      Sewage; and

·      General refuse.

 

7.3.2        Operational Phase

The following wastes will be generated from the operation of the Proposed Beach Development:

 

·      Sewage; and

·      General refuse.

 

7.4              Assessment Methodology

 

The potential environmental impacts associated with the handling and disposal of waste arising from the construction and operation of the Proposed Beach Development were assessed in accordance with the criteria presented in Annexes 7 and 15 of the EIAO-TM and summarised as follows:

 

·          Estimation of the types and quantities of the wastes to be generated based on information provided by the engineering design team and the relevant research and studies on waste arisings;

 

·          Assessment of the secondary environmental impacts due to the management of waste with respect to potential hazards, air and odour emissions, noise, wastewater discharges and traffic; and

 

·          Assessment of the potential impacts on the capacity of waste collection, transfer and disposal facilities.

 

7.5              Evaluation of Impacts

 

7.5.1        Construction Phase

 

Dredged Marine Sediments

 

The beach development works will involve dredging and filling. Various beach layouts and construction methods have been examined with respect to the practicality of constructing the Proposed Beach Development without dredging.  It is concluded that dredging is unavoidable, however the proposed dredging works have been kept to minimum.  Dredging will be required for foundation formation of the proposed groynes and removal of 500mm thick granular soil from the existing beach areas.  Dredging activities will be conducted within the Project Site as shown in Figure 1.1.   Table 7.3 summarize the quantity of dredged materials to be generated.

Dredging in the offshore area will be conducted by Closed Grab Dredger.  The formation of the 200m long beach with a groyne at end of the beach will generate a total of approximately 10,500 m³ of dredged sediment.  The dredging activities will take about 2 months (i.e. tentatively from February 2009 to March 2009). 

 

Table 7.3:   Quantity of Dredging Marine Sediment

Description	Dredged Marine Sediment (m3)
Seabed reformation/ Groyne Construction	10,500

A preliminary marine sediment sampling programme has been undertaken as part of the EIA Study to provide an indication of the quality of the sediment and the volumes of different types of sediment to be dredged.  The sediment sampling programme (including the sampling stations, the chemical analysis suite and the biological testing programmes) was developed based on the guidelines described in ETWBTC 34/2002.  The sampling and testing programmes are summarised in Table 7.4 and the sampling locations are presented in Figure 7.2.

 

Table 7.4:   Marine Sediment Sampling Locations

Sampling Location	Coordinates		Vibrocore Sampling	Interstitial Water (for TBT)	Elutriation and Marine Water Test
	Northing (m)	Easting (m)
SS1	841401.05	836818.49	P	P	P
SS2	841421.86	836773.17	P	P	P
SS3	841459.93	836680.53	P	P	P
SS4	841493.11	836857.52	P	P	P
SS5	841512.75	836811.54	P	P	P
SS6	841551.91	836719.80	P	P	P
SS7	841585.07	836896.75	P	P	P
SS8	841604.72	836850.78	P	P	P
SS9	841628.28	836795.60	P	P	P

 

Samples from the vertical profile of sediments to be dredged were collected using a vibrocore device to the required dredging depth of 3 m or until further drilling was not possible, whichever was the shallowest.  The vibrocore samples were cut on site at the proposed sampling depths from the existing seabed surface at -0.9m, -1.9m and -2.9m.  The sediment samples for further biological testing were also concurrently collected.  All vibrocores collected were of depth less than 3m due to thin layer of marine deposit in the area.  It should be noted that the sample taken at depths of 0.0-0.2m and 0.0-0.5m for virbocores SS1 and SS2, respectively, were not tested due to its sandy material content.  In addition, a reference sediment sample was collected at the EPD routine sediment monitoring station PS6 (Hong Kong Metric coordinates: 850234E, 820057N) in the Port Shelter. 

 

The contaminants tested include all the contaminants stated in Table 1 - Analytical Methodology in Appendix B of ETWBTC No 34/2002 plus PCBs and 12 Chlorinated Pesticides.

 

Tier III biological screening was also performed on samples where one or more contaminant level exceeded the LCEL.  The ecotoxicological-testing programme featured a suite of tests that include three phylogenetically distinct species (amphipod, polychaete and bivalve larvae) which interact with marine sediments in different ways.  The objective of the bioassays was to determine if the potential toxicological impacts of marine disposal of the dredged sediment on the marine biota, and whether there is any difference in the toxicity of the sediments samples taking from the Project Site and the reference station (collected from a clean area in Port Shelter, New Territories).  The chemical and biological analysis results of the marine sediment are presented in Table 7.5. 

 

According to the sediment classification results shown in Table 7.5, sediment samples from drill holes SS1, SS2, SS4, SS7 and SS8 required biological testing in order to determine the disposal arrangements.  Biological testing has been carried out for these samples and analysis results are shown in Table 7.5. 

 

Table 7.5:      Marine Sediment Testing Result

Sample Reference		Heavy Metals (mg kg-1)									Sediment Category	Biological Sample No.	Failed Biological Tests			Final Disposal
Drill hole No.	Depth (m) From – To	Cadmium (Cd)	Chromium (Cr)	Copper (Cu)	Nickel (Ni)	Lead (Pb)	Zinc (Zn)	Mercury (Hg)	Arsenic (As)	Silver (Ag)			Amphipod	Bivalve	Polychaete
Reporting Limits		0.2	8	7	4	8	20	0.05	1	0.1
LCEL		1.5	80	65	40	75	200	0.5	12	1
UCEL		4	160	110	40	110	270	1	42	2
SS1	0.2-0.9m	<0.2	<8	<7	<4	13	<20	<0.05	17	<0.1	M	CS1	x			Type 2 Confined
SS1	0.9-1.2m	<0.2	<8	<7	<4	31	26	<0.05	24	<0.1	M	CS1	x			Type 2 Confined
SS2	0.5-.0.9m	<0.2	<8	<7	<4	17	20	<0.05	17	<0.1	M	CS2				Type 1 Dedicated
SS2	0.9-1.9m	<0.2	<8	<7	<4	18	23	<0.05	28	<0.1	M	CS2				Type 1 Dedicated
SS2	1.9-2.5m	<0.2	<8	<7	<4	25	<20	<0.05	42	<0.1	M	CS2				Type 1 Dedicated
SS3	0.0-0.9m	<0.2	<8	<7	<4	13	<20	0.07	5.8	<0.1	L					Type 1
SS3	0.9-1.9m	<0.2	<8	<7	<4	11	<20	0.05	5	<0.1	L					Type 1
SS3	1.9-2.8m	<0.2	<8	<7	<4	20	<20	0.06	12	<0.1	L					Type 1
SS4	0.0-0.9m	<0.2	<8	<7	<4	12	20	<0.05	6.9	<0.1	L					Type 1
SS4	0.9-1.3m	<0.2	<8	<7	<4	12	<20	<0.05	27	<0.1	M	CS3				Type 1 Dedicated
SS5	0.0-0.9m	<0.2	<8	<7	7.8	19	<20	<0.05	2.5	0.12	L					Type 1
SS6	0.0-0.9m	<0.2	<8	<7	<4	8.5	<20	0.10	3.3	<0.1	L					Type 1
SS6	0.9-1.6m	<0.2	<8	<7	<4	<8	<20	0.06	4.2	<0.1	L					Type 1
SS7	0.0-0.9m	<0.2	<8	<7	<4	13	<20	<0.05	6.1	<0.1	L					Type 1
SS7	0.9-1.3m	<0.2	<8	<7	<4	13	<20	<0.05	14	<0.1	M	CS3				Type 1 Dedicated
SS8	0.0-0.9m	<0.2	<8	<7	<4	12	<20	0.08	10	<0.1	L					Type 1
SS8	0.9-1.7m	<0.2	<8	<7	<4	8.8	<20	0.07	16	<0.1	M	CS3				Type 1 Dedicated
SS9	0.0-0.9m	<0.2	<8	<7	<4	10	<20	0.07	4.0	<0.1	L					Type 1
SS9	0.9-1.9m	<0.2	<8	<7	<4	<8	<20	<0.05	2.5	<0.1	L					Type 1
SS9	1.9-2.1m	<0.2	<8	<7	<4	<8	<20	<0.05	8.5	<0.1	L					Type 1
Notes: (a)         Bold and unlined = Exceeding LCEL, classified as Category M, which requires biological screening to determine the types of disposal site (ie Type 1 or Type 2 Disposal). (b)         x = Failed biological testing. (c)         Type 1 Disposal = disposal at an open sea disposal. (d)         Type 1 Dedicated Site = disposal at a dedicated open sea disposal site. (e)      Type 2 Disposal = disposal at confined marine disposal site

 

According to the ETWB TC(W) No. 34/2002, sediment is deemed to have failed the biological test if it fails in any one of the three toxicity tests.  Due to the failure on the 20-Day Polychaete Test, the sediment to be dredged represented by sample collected at location SS1 must be dredged with great care and transported to the confined mud pits at East Sha Chau for disposal (ie Type 2 – Confined Marine Disposal). 

 

The latest engineering review suggested that dredging depth will generally be limited to 0.5 - 1m below seabed level, and will not be greater than 3m.  The estimated in-situ quantities of contaminated and uncontaminated sediment to be dredged for different work activities are summarized in Table 7.6 and the Sediment Disposal Requirement Plan is shown in Figure 7.3 and 7.4.

 

Table 7.6:         Estimated Quantity of Different Types of Marine Sediment to be Dredged (m³)

Disposal Options	Seabed	%
Type 1 Open Sea Disposal	6,380	60.76%
Type 1 Dedicated Open Sea Disposal Site	2,620	24.95%
Type 2 Confined Marine Disposal Site	1,500	14.28%
Total	10,500	100%
Note: (a)      The quantity of contaminated sediment was estimated based on locations where sediment samples were classified as Category L and Category M within the proposed dredged areas.  The estimated dredging depth would generally in the range of 0.5m to 1m and not greater than 3m.

 

It is estimated that a total of 17 barge trips will be required to transport the dredged sediments during the dredging period ^([1]).  The dredged marine sediments will be loaded onto barges using closed grabs and transported to the appropriate disposal sites depending on their level of contamination.  In accordance with the requirements of ETWBTC No 34/2002, the Category M sediments will be dredged and transported with great care in order to avoid leakage of contaminated sediment into the sea.  With the implementation of the mitigation measures recommended in Section 7.6, sediment disposal at the designated disposal sites will not cause adverse environmental impacts.

 

The Sediment Quality Report (SQR) has been prepared in accordance with the requirements of ETWBTC 34/2002 for approval as required under the Dumping at Sea Ordinance and attached in Appendix F.

 

The final disposal site will be determined by the MFC and a dumping licence will be obtained from the DEP prior to the commencement of the dredging works.  The potential water quality impacts due to the dredging and disposal of these sediments have been assessed and are presented in Section 6, Water Quality Impact Assessment.  The assessment concluded that the dredging works and proper disposal of the sediment will meet the relevant water quality impact assessment criteria in the EIAO-TM with the implementation of the recommended mitigation measures.

 

Demolition Waste

 

Demolition for existing structures and site clearance (450 m³) and for building & landscaping works and western drainage channel (20 m³) will produce approximately 470 m³ of demolition waste consist of a mixture of vegetable matter and inert materials.  The demolition works will be completed within 7 months (i.e. tentatively from December 2008 to July 2009).  Sequential demolition method will be used to facilitate the separation of inert and non-inert materials as far as possible to enable the beneficial use of the inert materials and to minimise waste disposal costs.  Assuming a bulking factor of 1.4, it is estimated that about 1 truck trips will be required each day to dispose of the demolition waste ^([2]).  Construction and demolition (C&D) materials generated will be separated/ sorted into inert and non-inert portions on site.  Inert C&D materials will be reused on site (e.g. as filing materials) as far as possible.  The surplus inert C&D materials should be delivered to public fill for re-use purpose.  The delivery of the C&D materials to public fill reception facilities and landfills will be monitored using trip ticket system in accordance with ETWB TCW No. 31/2004..    

 

            Excavated Materials

 

Excavation and backfilling will be required to form a small piece of land to accommodate the future beach facilities/buildings, road and footpath, car park, drainage and sewerage facilities.  The site formation works will last for 7 months, tentatively from December 2008 to June 2009. 

 

A review of old and recent aerial photographs has indicated that changes of the Project Site in the past 2 decades are due to natural changes or by village development (see Figure 7.5).  The area was used as agriculture land in 1940's to 1970's and left naturally in early 1980's.  The existing hard standing area at the western side of the site was formed in late 1980's, but no structure was built on top of that area.  No industrial development has ever been established near to the area.  All connections to the existing box culverts are road drains and stream courses and the discharge is mainly surface run-off.  It is unlikely that the effluent from box culverts contains high level of contaminations.  Therefore no contamination issue is expected on the Project Site and the excavated soil/material would be free of contaminants and can be re-used on site or disposed of at public fill.

 

The excavation works will mainly be carried out in the first 5 months and will generate approximately 13,800 m³ of excavated materials (mainly soil).  The estimated quantities of excavated materials are presented in Table 7.7.  Excavated soil will be reused as fill material within the Project Site as far as is practicable.  It is estimated that 60% (i.e. 8,280 m³) of excavated soil can be reused for backfilling and the remaining 5,520 m³ will require off-site disposal.  The location of the temporary stockpiling area for the construction of the Proposed Beach Development is shown in Figure 4.2 and Figure 7.6 shows the locations of soil excavation and backfilling.  Assuming a bulking factor of 1.1 for soil and a truck capacity of 6 m³, about 9 truck trips ⁽[3]⁾ will be required each day to dispose the surplus excavated soil off-site.  The excavated soil could be used as fill for reclamation and land formation projects.  However, if the soil could not be accepted by other projects, it will be delivered to the public fill reception facilities. 

 

Table 7.7: Summary of Quantity of Excavated Materials

Construction Works	Excavation Materials (m3)
Building & Landscaping	800
Roadworks (road & footpath)	600
Car Park	4,000
Vertical Seawall / Retaining Wall	2,000
Western Drainage Channel	4,500
Eastern Box Culvert	1,900
Total	13,800
Quantity to be reused on-site	8,280
Quantity for off-site disposal	5,520

 

Construction Waste

 

C&D materials (consisting of waste concrete, packing materials, plastics, metal, concrete, wood, etc) will be generated from the new building construction.  The total gross floor area (GFA) to be constructed at the Project Site is approximately 2,245 m².  Based on a generation rate of 0.1 m³ per m² of GFA constructed ^([4]), it is estimated that a total of about 225 m³ of C&D materials will be generated.  These materials will be sorted on-site for public fill (inert portion) (about 180 m³) and construction waste (about 45 m³) in order to reduce the amount of construction waste to be disposed of at landfills.  The public fill will be reused on-site as much as practical and the surplus will be reused at other concurrent reclamation/land formation projects or disposed of at Government public filling reception facilities.

 

With the proper implementation of good construction site practice and the mitigation measures, the handling and disposal of a small amount of C&D materials to be generated from the new building construction works will not cause adverse dust, noise or water quality impacts.

 

Chemical Wastes

 

Chemical waste, as defined under the Waste Disposal (Chemical Waste) (General) Regulation, includes any substance being scrap material, or unwanted substances specified under Schedule 1 of the Regulation.  A complete list of such substances is provided under the Regulation; however, substances likely to be generated from the construction of the Proposed Beach Development will, for the most part, arise from the maintenance of construction plant and equipment.  These may include, but not limited to the following:

 

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

 

·      Used paint, engine oils, hydraulic fluids and waste fuel;

 

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

 

·      Spent solvents/solutions from equipment cleaning activities.

 

Chemical wastes may pose environmental, health and safety hazards if not stored and disposed of in an appropriate manner as outlined in the Waste Disposal (Chemical Waste) (General) Regulation and the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes.  These hazards may include:

 

·      Toxic effects to workers;

 

·      Adverse effects on air, water and land from spills; and

 

·      Fire hazards.

 

The amount of chemical waste that will arise from the construction activities will be highly dependent on the Contractor’s on-site maintenance activities and the quantity of plant and equipment utilized.  All barges and marine vessel will comply with the standard operational procedure and design for prevention of oil pollution.  With respect to the nature of construction works and the number of construction plant and equipment to be used on site, it is estimated that the quantity of chemical waste to be generated will be small (in the order of few hundreds litre for the whole construction phase).  

 

With the incorporation of suitable arrangements for the storage, handling, transportation and disposal of chemical wastes under the requirements stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Waste, no adverse environmental and health impacts, and hazards will result from the handling, transportation and disposal of chemical waste arising from the Proposed Beach Development.

 

Sewage

 

Sewage will be generated from the construction workforce, site office’s sanitary facilities and from portable toilets.  If not properly managed, these wastes could cause adverse water quality impacts, odour and potential health risks to the workforce by attracting pests and other disease vectors.

 

It is estimated that a maximum of 100 workers will be working on site at any one time during the construction period and maximum 0.1 m³ of sewage will be generated per day ^([5]).  An adequate number of portable toilets will be provided at the Project Site to ensure that sewage from site staff is properly collected.  No adverse environmental impacts are envisaged provided that the portable toilets are properly maintained by a licensed contractor and the collected sewage is disposed at the designated Sewage Treatment Works (eg Tai Po Sewage Treatment Works). 

 

General Refuse

 

The presence of a construction site with workers and associated site office will result in the generation of general refuse (mainly consist of food waste, aluminium cans and waste paper) which requires off-site disposal.  The storage of general refuse has the potential to give rise to adverse environmental impacts.  These include odour if the waste is not collected frequently (for example, daily), windblown litter, water quality impacts if waste enters water bodies, and visual impact. 

 

Assuming up to 100 construction workers will be working on site at any one time, with a general refuse generation rate of 0.65 kg per worker per day ^([6]), the amount of general refuse to be generated will be about 65 kg per day.

 

Recyclable materials such as paper and aluminium cans will be separated and delivered to the local recyclers.  An adequate number of waste containers will be provided to avoid spillage of waste.  The non-recyclable waste will be collected and disposed of at the North East New Territories Landfill (NENT) on a daily basis.  With respect to the small quantity of general refuse to be transferred, it is not anticipated that it will cause adverse operational impact to these facilities.

 

Provided that the mitigation measures recommended in Section 7.6 are adopted, no adverse environmental impacts are expected to arise from the storage, handling, transport and disposal of general refuse. 

 

7.5.2        Operational Phase

 

Dredged Materials & Chemical Waste

 

The Project has been designed with a view to reduce disposal arising.  No maintenance dredging is required and no dredged materials will be produced during operational phase. 

 

In case oil dispersants will be use, approval from EPD will be sought and will comply with all requirements to minimize potential water quality impacts.

 

Sewage

 

Sewage will mainly arise from the visitors to the Proposed Beach Development.  It is estimated that the peak numbers of visit during summer time would be approximate 4,000 visitors per day.  Taking into account the estimated time spent on the beach and the associated activities, the average daily sewage generation rate from beach visitor is estimated to be 10 m³ per day with a peak flow rate of 30 litres per second ^([7]).  The sewer system for the Proposed Beach Development will be designed with an adequate capacity and connected to public sewerage conveying to the Tai Po Sewage Treatment Works for treatment.  Therefore, no adverse water quality impacts are envisaged.   

 

General Refuse

 

General refuse will arise from the visitors to the Proposed Beach Development.  General refuse may consist of food waste, plastic, aluminium can and waste paper.  A general refuse generation rate of 0.38 kg per visitor per day was assumed ^([8]) and it is estimated that the amount of general refuse to be generated will be about 1,520 kg per day.

 

A waste recycling and collection system using 3-coloured waste separation bins will be provided at the Proposed Beach Development.  Recyclable materials (i.e. paper, plastic bottle and aluminium can) will be separated and delivered to recyclers in order to reduce the amount of general refuse to be disposed of at landfill.  The non-recyclable general refuse will be disposed of by refuse collecting vehicles transporting the wastes directly to landfill on a daily basis.  With respect to the small quantity of general refuse to be disposed of, no adverse environmental impact associated with the handling and disposal of the refuse is anticipated.

 

7.6              Mitigation Measures and Residual Impacts

 

This section recommends the mitigation measures and good site practices to avoid or reduce potential adverse environmental impacts associated with handling, collection and disposal of waste arising from the construction and operation of the Proposed Beach Development.

 

The Contractor should incorporate these recommendations into a Waste Management Plan for the construction works.  The Contractor should submit the plan to Project Proponent’s Engineer Representative for endorsement prior to the commencement of the construction works.  The plan should incorporate site-specific factors, such as the designation of areas for the segregation and temporary storage of reusable and recyclable materials.

 

It will be the Contractor’s responsibility to ensure that only reputable licensed waste collectors are used and that appropriate measures to reduce adverse impacts, including windblown litter and dust from the transportation of these wastes, are employed.  In addition, the Contractor must ensure that all the necessary permits or licences required under the Waste Disposal Ordinance are obtained for the construction phase.

 

Waste Management Hierarchy

 

The various waste management options are categorised in terms of preference from an environmental viewpoint.  The options considered to be most preferable have the least environmental impacts and are more sustainable in the long term.  The hierarchy is as follows:

 

·   Avoidance and reduction;

·   Reuse of materials;

·   Recovery and recycling; and

·   Treatment and disposal.

 

The above hierarchy has been used to evaluate and select waste management options.  The aim has been to reduce waste generation and reduce waste handling and disposal costs. 

 

The Contractor should consult the EPD for the final disposal of wastes and implement the following good site practices and mitigation measures:

 

·  Nomination of approved personnel 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 for  disposal;

 

·   Appropriate measures to reduce windblown litter and dust transportation of waste by either covering trucks or by transporting wastes in enclosed containers;

 

·   Separation of chemical wastes for special handling and appropriate treatment at the Chemical Waste Treatment Centre;

 

·   Regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors; and

 

·   A recording system for the amount of wastes generated/recycled and disposal sites.

 

Waste Reduction Measures 

 

Good management and control can prevent generation of significant amount of waste.  Waste reduction is best achieved at the planning and design stage, as well as by ensuring the implementation of good site practices.  Recommendations to achieve waste reduction include:

 

·  Segregation and storage of different types of waste in different containers, skips or stockpiles to enhance reuse or recycling of material and their proper disposal;

 

·   Encourage collection of aluminium cans and waste paper by individual collectors during construction with separate labelled bins being provided to allow the segregation of these wastes from other general refuse generated by the workforce;

 

·   Any unused chemicals and those with remaining functional capacity be recycled as far as possible;

 

·   Use of reusable non-timber formwork to reduce the amount of C&D materials;

 

·  Prior to disposal of construction waste, wood, steel and other metals should be separated, to the extent practical for re-use and/or recycling to reduce the quantity of waste to be disposed at landfills;

 

·   Proper storage and site practices to reduce the potential for damage or contamination of construction materials; and

 

·   Plan and stock construction materials carefully to reduce amount of waste generated and avoid unnecessary generation of waste.

 

7.6.1        Dredging Materials

 

The final disposal site for the dredged sediments should be determined by the MFC and a dumping licence should be obtained from EPD prior to the commencement of the dredging works.  Uncontaminated sediments should be disposed of at open sea disposal sites designated by the MFC.  For contaminated sediments requiring Type 2 confined marine disposal, relevant contract documents should specify the allocation conditions of the MFC and EPD.

 

7.6.2        Excavated Materials and C&D Waste

 

Management of Waste Disposal

The contractor should open a billing account with EPD in accordance with the Waste Disposal (Charges for Disposal of Construction Waste) Regulation for the payment of disposal charges.  Every waste load transferred to Government waste disposal facilities such as public fill, sorting facilities, or landfills should require a valid “chit” which contains the information of the account holder to facilitate waste transaction recording and billing to the waste producer.  A trip-ticket system should be established in accordance with ETWBTC No. 31/2004 to monitor the reuse of surplus excavated materials off-site and disposal of construction waste and general refuse at transfer stations/landfills, and to control fly-tipping.  The billing “chit” and trip-ticket system should be included as one of the contractual requirements and implemented by the contractor.  Regular audits of the waste management measures implemented on-site as described in the Waste Management Plan should be conducted.

A recording system (similar to summary table as shown in Annex 5 and Annex 6 of Appendix G of ETWBTC No. 19/2005) for the amount of waste generated, recycled and disposed of (including the disposal sites) will be established during the construction phase.

 

Measures for the Reduction of C&D Materials Generation

 

Public fill and construction waste should be segregated and stored in different containers or skips to facilitate reuse or recycling of the public fill and proper disposal of the construction waste.  Specific areas of the work site should be designated for such segregation and storage if immediate use is not practicable.

 

To reduce the potential dust and water quality impacts of site formation works, C&D materials should be wetted as quickly as possible to the extent practicable after excavation/filling.

 

7.6.3        Chemical Waste

 

The Contractor should register as a chemical waste producer with the EPD.  Chemical waste, as defined by Schedule 1 of the Waste Disposal (Chemical Waste) (General) Regulation, should be handled in accordance with the Code of Practice on the Packaging, Handling and Storage of Chemical Wastes.  Containers used for the storage of chemical wastes should:

 

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

 

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

 

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

 

The storage area for chemical wastes will:

 

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

 

·    Be enclosed on at least 3 sides;

 

·    Have an impermeable floor and bunding, of capacity to accommodate 110% of the volume of the largest container or 20% by volume of the chemical waste stored in that area,  whichever is the greatest;

 

·    Have adequate ventilation;

 

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

 

·    Be arranged so that incompatible materials are appropriately separated.

 

Chemical waste should be collected by a licensed chemical waste collector to a facility licensed to receive chemical waste, such as the Chemical Waste Treatment Facility.

 

7.6.4        Sewage

 

An adequate number of portable toilets should be provided for the on-site construction workforce during construction phase.  All portable toilets should be maintained in a state that will not deter the users from using them.  Night soil should be regularly collected by a licensed collector for disposal.  The sewage generated from the visitors during operation of the Proposed Beach Development should be discharged to the adjacent foul sewer conveying to Tai Po Sewage Treatment Works for treatment. 

 

7.6.5    General Refuse

 

General refuse should be stored in enclosed bins or compaction units separately from construction and chemical wastes.  A reputable waste collector should be employed to remove general refuse from the site, separately from construction and chemical wastes, on a daily basis to reduce odour, pest and litter impacts.  The burning of refuse on construction sites is prohibited by law.

 

Recycling bins should be provided at strategic locations to facilitate recovery of aluminium cans and waste paper from the Project Site.  Materials recovered should be sold for recycling.

 

7.6.6        Staff Training

 

Training should be provided to workers on the concept of site cleanliness and appropriate waste management procedures, including waste reduction, reuse and recycling at the beginning of the construction works.

 

7.6.7        Residual Impacts

 

There will be no residual impact due to the Proposed Beach Development if the recommended mitigation measures are properly implemented.

 

7.7              Environmental Monitoring and Audit Requirements

 

7.7.1        Construction Phase

 

To facilitate monitoring and control over the contractors’ performance on waste management, a waste monitoring and audit programme should be implemented throughout the construction phase.  The aims of the monitoring and audit programme are:

 

·  To review the Contractor’s WMP including the quantities and types of C&D materials generated, reused and disposed of off-site; the amount of fill materials exported from/imported to the site and the quantity of timber used in temporary works construction for each process/activity;

 

·   To monitor the implementation and achievement of the WMP on site to assess its effectiveness; and

 

·   To monitor the follow-up action on deficiencies identified.

Joint site audits by the Environmental Team and the Contractor should be undertaken on a weekly basis.  Particular attention should be given to the Contractor’s provision of sufficient spaces, adequacy of resources and facilities for on-site sorting and temporary storage of C&D materials.  The C&D materials to be disposed of from the Project Site should be visually inspected.  The public fill for delivery to the off-site stockpiling area should contain no observable non-inert materials (e.g., general refuse, timber, etc).  Furthermore, the waste to be disposed of at refuse transfer stations or landfills should as far as possible contains no observable inert or reusable/recyclable C&D materials (e.g., soil, broken rock, metal, and paper/cardboard packaging, etc).  Any irregularities observed during the weekly site audits should be raised promptly to the Contractor for rectification.

 

To facilitate assessment of the effectiveness of the waste management measures, the WMP should state the performance targets to be achieved in reducing generation of C&D materials taking account the site constraints.  The performance targets should cover the following items and should be agreed with the Project Proponent at the beginning of the contract.

 

·   The percentage of excavated materials to be sorted to recover the soil and broken rock for reuse on site or deliver to the off-site stockpiling area;

 

·   The percentage of metal to be recovered for collection by recycling contractors; and

 

·   The percentage of cardboard and paper packaging (for plant, equipment and materials) to be recovered.  The recovered materials will be properly stockpiled in dry and covered condition to prevent cross contamination by other wastes.

 

The findings of the waste audits should be reported in the Environmental Monitoring and Audit Reports.

 

7.7.2        Operation Phase

 

As it is not expected that large quantities of waste will be generated from the operation of the bathing beach and no adverse environmental impacts will arise with the implementation of good waste management practices.  Waste monitoring and audit programme for the operational phase of the Proposed Beach Development will not be required.

 

7.8              Conclusions

 

The key potential impacts during the construction phase are related to wastes generated from dredging, demolition works, seawall and groyne construction, culvert diversion and construction and new building construction.

 

It is estimated that a total of approximate10,500 m³ of marine sediment will be dredged.  About 6,380 m³ of the sediments are uncontaminated and can be disposed of at the open sea disposal sites and about 2,620 m³ of the Category M sediment (which passed the biological screening) will be disposed of at dedicated open sea disposal sites.  The remaining 1,500 m³ of the Category M (which failed the biological screening) will have to be disposed of at the confined marine disposal site at East Sha Chau.  The final disposal site for the dredging sediments will be determined by the MFC and a dumping licence will be obtained from EPD prior to the commencement of the dredging works. 

 

About 13,800 m³ of excavated materials will be generated during construction phase and 8,280 m³ (about 60%) of which will be reuse on-site.  The surplus excavated soil will be reused in other concurrent construction projects in Hong Kong or disposed of at public fill reception facilities.

 

About 470 m³ of demolition waste consist of inert and non-inert port (e.g. vegetable matters) will be generated during construction phase.  Approximately 225 m³ of C&D materials will be generated from new building construction.  A maximum of 0.1m³ of sewage and 65kg of general refuse will be generated by workers each day.  A small quantity of chemical waste (mainly used lube oil from maintenance of heavy machinery) will be generated.  In view of the small quantity of various wastes to be generated, the handling and disposal of these wastes at the licensed waste disposal facilities will not cause adverse environmental impacts.

 

During the operational phase, it is estimated that of 10 m³ of sewage and 1,520 kg of general refuse will be produced each day by visitors during peak season.  In view of the small quantity of sewage and general refuse to be generated and their proper disposal to foul sewer or transfer station/landfill, no adverse environmental impact associated with the management of these wastes is anticipated during the operation of the Proposed Beach Development.

 

With the implementation of the recommendations in Section 7.6, the potential environmental impacts arising from storage, handling, collection, transport and disposal of wastes will meet the criteria specified in the EIAO-TM.  No adverse waste management impact is anticipated.  No residual and cumulative environmental impacts and hazards associated with handling and disposal of wastes arising from the construction of Proposed Beach Development are anticipated.

 

A Waste Management Plan should be prepared by the Contractor and should be audited through the environmental monitoring and auditing (EM&A) programme recommended in Section 7.7 to minimize the potential environmental impacts arising from waste management.