8.                  WASTE IMPACT ASSESSMENT

 

8.1              Introduction

 

8.1.1        This waste assessment examines the quantity, quality and timing of potential sources of waste which will arise from the construction and operation of the Spur Line. Both construction waste, and solid waste will be considered. Solid waste includes domestic waste, commercial and industrial waste, chemical waste, special wastes and other wastes, while construction and demolition waste includes most wastes arising during construction. Where unacceptable waste impacts are identified, appropriate mitigation measures are recommended. Disposal options will be outlined for each type of waste, and the responsibilities for disposal or recycling discussed.

 

8.1.2        The methodology follows the criteria laid out in the TM on EIA Process in Annexes 7 and 15. The most important legislation regulating waste arisings is the Waste Disposal Ordinance [Cap 354].

 

8.1.3        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 both construction and operational waste management strategies and control measures/routings (including final disposal sites) in accordance with the current legislative and administrative requirements for the disposal of construction waste, including waste reduction, reuse and recycling for inclusion into contract documents; and

 

(iii)       recommend measures for the disposal of inert materials and wastes.

 

8.2              Construction Waste

 

Introduction

 

8.2.1        Construction waste includes waste arising from land excavation, formation, civil/building construction, roadwork, renovation or demolition activities. Waste includes various types of building debris, rubble, earth, concrete, timber and mixed site clearance materials. The Contractor is responsible for transfer of the waste material to public filling areas, reclamations, marine spoil grounds or landfills, depending on the type of material and the percentage of inert material.

 


8.2.2        Careful calculation of waste quantities and the speed of their generation has allowed the formulation of plans for their efficient removal and disposal, with the aim of minimal disruption to traffic flow and maximum environmental protection. In addition elimination of over-ordering of construction materials will reduce waste.

 

8.2.3        The SAR 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 construction materials. During the construction period the contractor, engineer and environmental assessors should work closely together with a view to reducing the volumes of materials requiring removal and final disposal.

 

8.2.4        The Spur Line works will involve piling works to support the viaduct along the major length of the alignment and some rock blasting for a cutting through the Pak Shek Au area. The main construction wastes generated from these construction activities will be:

 

·                      site clearance waste/demolition waste

·                      excavated materials

·                      concrete waste; and

·                      general works waste

 

8.2.5        Training of construction staff should be undertaken by the Contractor in order to increase awareness of waste management issues. Requirements for staff training should be included in the contractors site waste management plan.

 

Site Clearance Waste/Demolition Waste

 

8.2.6        The Spur Line bisects an area comprising agricultural land, fish ponds, open storage and temporary structures. Site clearance works will involve the removal of vegetation (mainly grasses and shrubs), demolition and building materials (from temporary structures and village houses) and a small portion of the available topsoil.

 

8.2.7        Demolition of the temporary structures and houses will generate concrete rubble, plastics, metal, glass, asphalt from surfaces, wood and refuse.

 

8.2.8        All construction wastes should be sorted on site into inert and non inert components. Non inert materials (wood, glass and plastic) should be disposed of to landfill whilst inert materials (soil, rubble, sand, rock, brick and concrete) should be separated and disposed of at public filling areas operated by CED. Steel and other metals should be recovered from demolition waste and recycled as far as practicably possible.

 


8.2.9        The identification of final disposal sites for spoil created by the construction works should be considered during the detailed design stage of the Project. Disposal of Construction and Demolition (C&D) waste with not more than 230 % inert material is likely to be to NENT Landfill but could be to any of Hong Kong’s three strategic landfills.

 

8.2.10    In order to avoid dust or odour impacts, any vehicle leaving a works area carrying C&D waste or public fill should have their load covered. Vehicles should be routed as far as possible to avoid sensitive receivers in the area.

 

8.2.11    Some good quality reusable topsoil is expected from site clearance works across Long Valley’s agricultural land. This can be stockpiled and used later in final landscaping works, thus saving on costs for such works and transportation and environmental impacts of disposal. Some suitable material may also be generated from dredging of fishponds. This material can be mixed with the soil for landscaping. 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.

 

Excavated Materials

 

8.2.12    The majority of materials excavated will arise during pier foundation works for the 5 km of viaduct, foundation works for Lok Ma Chau station and the section of cutting between Kwu Tung and Chau Tau. It is expected that most of this material will be muddy deposits from fishponds and rock from the cutting. Rock may be cut with a rock drill. The relative effects of these methods from an air and noise impact are discussed in the relevant chapters.

 

8.2.13    Excavated material from the fishponds may be stockpiled, as mentioned above, provided measures are taken to reduce odour and run-off. There is a potential that this material may be contaminated with high levels of organics, and therefore be unsuitable for re-use on site. In this case, the fishpond spoil should be drained and disposed of in accordance with WBTC 22/92. In the case that the pond material is found to be uncontaminated, it may be drained and re-used for suitable purposes on site. Measures to control dust pollution and runoff from stockpiles are given in the relevant chapters for air and water pollution.

 

8.2.14    Some contaminated material may require excavation in Kwu Tung or Pak Shek Au in order to clear land for the cutting or for formation of embankment or Emergency Vehicle Access (EVA) area. This material may comprise concrete from workshops or chemical storage areas, or contaminated solids. The level and type of contamination must first be determined, in accordance with the Contaminated Action Plan (CAP) described in the Contaminated Land Assessment Chapter of this report. Following sampling and assessment of the analysis results, remediation options will be considered. Where large volumes of contaminated soil are found, remediation should be considered as a first option. Smaller volumes of contaminated material, less contaminated soils, or concrete mixed waste may be disposed of to landfill. This option should only be considered after other options of in-situ treatment have been discounted. Details of remediation options are given in the Contaminated Land Assessment Chapter and proposals will be made in the Remediation Action Plan to be prepared before construction commences.

 

8.2.15    Effective from 1 July 1999, the Contractor must comply with the trip-ticket system for the disposal of Construction and Demolition (C&D) material (Works Bureau Technical Circular (WBTC) No. 5/99 Ref: WB(W)211/32/02).

 

8.2.16    Confirmation has to be sought from the Public Fill Sub-Committee (PFSC) and EPD regarding the availability of public filling facilities or a landfill, for inert C&D waste more than 100,000 m3 and non-inert C&D waste respectively.

 

8.2.17    Particular Specification of the Project shall include the following clauses with the terminology defined under WBTC No. 4/98:

 

·                      The Contractor shall produce a Construction and Demolition Material Disposal Delivery Form (the Form) for each and every vehicular trip transporting construction and demolition (C&D) material, i.e. public fill or C&D waste, off Site. The Contractor shall complete the Form in duplicate except for the Time of Departure.

 

·                      Prior to the vehicle leaving the Site, the Contractor shall present to the site supervisory staff the completed Form. The site supervisory staff shall retain a copy of the Form and return the original to the Contractor. The Form shall be carried on board the vehicle at all times throughout the vehicular trip.

 

·                      For each vehicular trip, the Contractor shall obtain a receipt from the operator of the public filling facility or the landfill. The Contractor shall submit the original receipt to the Engineer’s Representative within 5 working days# of the vehicular trip. Late return without any acceptable reason might be regarded as non-compliance by the Engineer’s Representative.

 

·                      The Contractor acknowledges and shall permit the Engineer Representative to request and obtain information from the operator of the Designated Disposal Tip verifying the receipt and the accuracy of the information on that receipt.

 


·                      All C&D material shall become the property of the Contractor when it is removed from the Site.

 

8.2.18    The Contractor will be required to complete the relevant details on a standard form and submit the form for stamping and collection by site supervisory staff and submit to Engineer Representative the receipt issued by the operator of the public filling facility / landfill after the disposal of the C&D material. Details to be included on the standard form and the receipt is included in the WBTC No. 5/99.

 

8.2.19    Table 8.1 provides details of the locations of fill requirements or generation, their timing and potential for re-use.

 

8.2.20    An estimate of the material volumes involved during excavation and volumes required for fill indicate that there will be a shortfall of material for the station foundation and formation of roads (temporary and permanent) along the alignment. All material which is re-useable should be retained for use within the site and the programme should be designed so that deficit and surplus can be balanced as far as possible. Fishpond material, in particular, can be re-used in the wetland compensation area to the west of the station works area, before major works on the station begin.

 

8.2.21    An estimate of the material volumes involved during excavation and volumes required for fill, as shown in Table 8.1, indicate that there will be a shortfall of material for the station foundation formation. However, if removal of pond bund material is minimized through appropriate ground preparation techniques such as the use of wick drains, and fill material is sourced from excavation along the alignment, this shortfall can be minimised.

 


Table 8.1  Materials Quantities and Balance during Construction of Spur Line

 

Works Area

Estimated Date of Works

Fill material required (m³)

Material generated (m³)

Balance

Potential source of material if required

Lok Ma Chau Station

March to June 2001

Surcharge material, some rock fill for haul road construction

Fishpond material to be excavated to allow for site formation. 307,000

Material to be brought in for surcharge.

Some fishpond material may be used in the creation of the wetland compensation are to the west of the station. This re-use depends on sediment quality, to be determined through chemical analysis. The remainder of the fishpond material to be drained and disposed of according to WBTC 22/92.

 

June 2001 to 2002

Site Formation

595,000

-

Material will need to be brought in by barge to supply the deficit.

-

Western Viaduct Alignment

July 2001 to May 2002

Road formation

50,000

-

Some of the material for road formation can be obtained from the surcharge discarded from the station site formation. Remaining volume to be brought in from outside.

-

Eastern Viaduct Alignment between embankment and River Beas

July 2001 to Jan 2002

Road formation

30,000

-

Some of the material for road formation can be obtained from the surcharge discarded from the station site formation. Remaining volume to be brought in from outside.

-

Cutting at Pak Shek Au

Sept 2001 to April 2002

-

50,000

Some of material generated may be used in remainder of alignment if required for road formation.

The quantity to be re-used depends on the contamination status. Contaminated material to be remediated on site or disposed of to landfill.

Embankments at Kwu Tung and Chau Tau

Sept 2001 to April 2002

200,000

Some contaminated material may have to be removed from the embankment areas. This should be tested and treated on site or disposed of to landfill.

Material will need to be brought in for this purpose.

-

Long Valley Viaduct Alignment

Nov 2001 to May 2002

Temporary road formation

Some vegetation removal during works in Long Valley. Small amounts.

Some of the material for road formation can be obtained from the surcharged discarded from the station site formation. Remaining volume to be brought in from outside.

-

Lok Ma Chau Station Infrastructure

2002 to 2003

Concrete, other materials, 4,000

Waste materials from construction 6,000

-

Re-use of materials should be practiced wherever possible.


Concrete Waste

 

8.2.22    Concrete is the main material likely to be used in the construction of the viaduct, foundations, stations and associated works. Of the volume of concrete supplied, it is assumed that approximately 3-5% of the concrete used will be lost to waste. Dry concrete waste will be sorted out from the other wastes and recycled for reuse or sorted for disposal at a public filling area e.g. Pak Shek Kok. Shotcrete is expected to be used for slope stabilisation works. There may be some surplus or rejected shortcrete.

 

General Works Waste

 

8.2.23    The following wastes will be generated during the construction of the railway track and Lok Ma Chau station:

 

·                      Wooden materials from formwork and site fencing;

·                      Chemical waste - oils, lubricants, paints and solvents;

·                      Aqueous waste;

·                      Slurries including bentonite slurries or similar grouts;

·                      Sewage; and

·                      Municipal waste.

 

Wooden materials, formwork and site fencing

 

8.2.24    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 at the viaducts and stations. Wooden materials are important and valuable resources.

 

8.2.25    All wooden materials used on site should be kept separate from other wastes. Wooden boards can be reused on site although the reusability and quantity of final waste depends on the shape and quality of the boards. Boards used should be capable of being reused at least five times, thus keeping the wastage rate down to around 20 %. Timber which cannot be reused should be sorted and stored separately from all inert waste before being disposed of to landfill. On-site incineration of wooden waste requires a permit from EPD in accordance with Section 43 of the Air Pollution Control Ordinance (Cap. 311), Open Burning Regulation (1995). It is an offence under law to openly burn construction waste. A number of private contractors will collect used formwork materials for local reuse or export to China. On completion of the construction phase, the boards should be sorted and grouped then distributed to other construction sites.

 

8.2.26    Reusable steel shutters should be used as a preferred alternative to formwork and falsework where possible.


8.2.27    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, the possibility of using metal fencing or building panels to provide site fencing should be considered. Building panels are cement structures with a lightweight concrete core. The material provides good sound and thermal insulation, as well as being both waterproof and fire resistant. These panels are easily recycled and reduce wastage of timber.

 

Chemical Waste

 

8.2.28    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.

 

8.2.29    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. Chemical waste should be collected by a licensed collector.

 

8.2.30    The major chemical waste types arising from the construction sites are likely to be oils, lubricants, paints and solvents. Oil waste may be in the form of raw waste, or as sundries such as spent oil filters, or materials used to absorb oil leaks. Various storage and disposal measures are recommended in the Code of Practice to minimise impacts from these chemical sources.

 

8.2.31    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 3 sides to prevent discharge due to accidental spillages or unintentional discharge from 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 greatest. Waste collected from any grease traps should be collected and disposed of by a licensed contractor.

 

 


8.2.32    Any construction plant which is likely to leak oil, should have absorbent inert material e.g. sand, placed beneath it. This material should be replaced on a regular basis and the contaminated material stored in a designated, secure place. Such relatively inert material is suitable for landfill disposal and can be disposed of via the normal waste stream.

 

8.2.33    Lubricants and waste oils 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. The Centre for Environmental Technology operates a Waste Exchange Scheme which can assist in finding receivers or buyers for chemical wastes.

 

8.2.34    Oil and lubricant wastes are classified as chemical wastes, and if not recycled, should be treated at the Chemical Waste Treatment Centre, Tsing Yi, or other sites licensed for the disposal of waste oil. A trip ticket system operates to control the movement of such chemical waste, and tickets have to be produced upon the request of EPD.

 

8.2.35    Some paints and solvents are classified as chemical waste and, if used on site, will be subject to the stringent requirements of the Waste Disposal (Chemical Waste) (General) Regulation. Empty paint cans should be recycled or collected as waste. Any dry paint waste should be swept up and collected in containers for disposal.

 

8.2.36    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. Storage areas should have adequate ventilation and be covered to prevent rain entering.

 

8.2.37    It is unlikely that bentonitie slurries will be used in construction of the Spurline. However, should they be used their handling and disposal should be in accordance with ProPECC PN 1/94 – Construction Site Drainage. This approach will encourage re-use where possible to minimise final disposal to marine dumping grounds.

 

            Aqueous Wastes

 

8.2.38    Requirements designed to protect against surface runoff include the use of sediment traps, settlement ponds, special drainage channels and bunding. Discharges from concrete works will be high in suspended solids and pH. These washings must be settled in a sedimentation pit, and possibly treated to reduce pH before discharge. Oil interceptors should be used where oily wastes are present, and must have a bypass for ease of disposal of oily wastes. Landtake under stockpiles or open working areas must be minimised wherever practicable and the stockpiles should be fenced and bunded to reduce erosion and sediment release. Runoff from the stockpiles should be collected in sediment traps. Solids accumulated in the sand traps, settlement tanks, manholes, and stream beds must be cleared out regularly and disposed of accordingly in order to maintain an effective system.

 

8.2.39    All discharged waters, including sewage and site runoff, should comply with the appropriate standards in the Technical Memorandum on Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters, prior to discharge. Advice on the handling and disposal of construction site discharges, including site runoff and contaminated wastewaters, is provided in the ProPECC Paper (PN1/94), Construction Site Drainage.

 

Wheel wash waste

 

8.2.40    All vehicles leaving any of the works areas must pass through a wheelwash at the site access/exit. If, at any time, further entry/exit points are created, similar facilities must be provided. The wheelwash must be regularly cleaned to remove sediment, a process which may produce a large volume of wastewater. To prevent excess sedimentation, and minimise possible contamination of local streams and water courses, these wastewaters should be directed into settlement ponds as far as practicable. The wastewater can then be reused on site. The maintenance of the wheelwash will be the responsibility of the Contractor undertaking the site formation works.

 

8.2.41    If the waste water contains a significant amount of oil and grease from vehicles, areas of sand for absorbing oily wash water should be set up by contractors. Liaison with RSD is essential for correct disposal.

 

Sewage

 

8.2.42    Sewage is characterised by high BOD and suspended solids, is enriched with nutrients and has high bacteriological counts. Domestic sewage generated from any additional site toilets, washing facilities and any temporary canteen provided for construction workers should be collected separately and disposed of or appropriately treated to comply with Government requirements. It is the responsibility of the contractor to ensure that sewage disposal complies with the standards set out in the Technical Memorandum on Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters. Sewage impacts and appropriate mitigation measures are dealt with in the Water Impact Assessment Chapter.

 


Municipal/Domestic Waste

 

8.2.43    Solid and liquid wastes will be generated by the construction workers during the clearance/construction period. The quantity of municipal waste generated is estimated to be 1.10 kg/employee/day (EPD, 1998). A temporary refuse collection station should be set up by the Contractor. Municipal waste should be collected regularly in black refuse bags and delivered to an approved Refuse Transfer Station or landfill as required by the Regional Services Department (RSD).

 

8.2.44    Provision and collection of skips for different types of recyclable waste is the responsibility of the contractor. Arrangements should be made directly with the recycling companies, for example, the paper merchants, to collect the waste as required.

 

8.2.45    A summary of the solid waste arising as a result of the construction phase is presented in Table 8.2.

 

Table 8.2

Construction Wastes Arising as a Result of Proposed Works

 

Area

Major Activities

Waste Type

Disposal

All

Site clearance

Vegetation

Topsoil

Pond Material

Landfill

Used for landscaping

Used for landscaping

Kwu Tung, Pak Shek Au,

Demolition

Concrete

Bricks/Tiles

Ferrous Metal

Wooden and other non-inert waste

Public Filling Area

Public Filling Area

Recycle

Landfill

Pak Shek Au cutting

 

Kwu Tung

Lok Ma Chau, Long Valley

Excavation

 

Fill Material

 

Contaminated concrete

Fish pond deposits

Soil material

To Lok Ma Chau Station works area or Public Filling Area

To landfill

Reuse within site for landscaping or mix with dry material

All, particularly temporary works areas at Sheung Shui, Kwu Tung and Lok Ma Chau

General site Activities

Sewage wastes

Municipal Wastes

Packaging Materials

Chemical

Waste Oil

Treatment

Landfill

Landfill

CWTP

Licensed Contractor

 


            Recycling or Re-use Facilities for Construction Wastes

 

8.2.46    As a result of the large variety of wastes which will be generated during the construction (and operation) of the Spur Line, the establishment of an efficient collection system is required to achieve environmental objectives. The system should also allow for recycling of certain materials and proper disposal of other materials as detailed in Table 8.3.

 

Table 8.3

Construction Waste types and their potential for recycling or re-use

 

Waste type

Works generating waste

Volumes lost as waste

Potential re-use or recycling

Disposal Options

Fill material and topsoil/pond material

Excavation of cutting at Pak Shek Au and piling works

None

Excess fill material produced during piling/ boring activities will be-re-used

All fill will be used within the works, specifically for Lok Ma Chau station construction

Unsuitable fill material (fishpond muds)

Excavation at Lok Ma Chau

Small amounts

Dried and reused when mixed with other over dry materials

All should be reused within works. Any excess should be disposed of at public filling area (if clean)

Concrete/

Asphalt

Road surfaces/ Demolition;

Construction of stations

3 - 5 %

Needs to be separated; re-useable material needs to be crushed

To public filling area

Wood formwork, fencing

Construction of viaducts.

Construction of stations.

Demolition.

20 %

Used as lower grade shuttering or fencing on-site or other sites

To landfill (final disposal)

Reinforcing steel, steel cable and shutters

Viaducts

Construction of stations

Demolition

1 %

Most material can be re-used after cleaning Reinforcement off cuts to be scrapped/recycled

Chemical waste

General construction site activities

Small amounts

Recycling/disposal firms will collect chemicals or waste oil, or refill oil containers

Chemical waste, including paints disposed of to treatment facility - REQUIRES LICENSE

Oil waste

 

 

 

Oil can be removed for recycling or soaked up by sand for disposal to landfill.

Grease trap waste

 

 

 

Grease trap waste collected and disposed of by licensed contractor.

Wheel wash waste

Vehicle use during general works

Total volume when replaced

Recycling through filter until replacement of water is required

Onto sand area where natural filtration occurs, and oils can be retained before landfill disposal.

Sewage

Where site workers are present

 

None

 

Municipal/Domestic waste

General site activities

Putrescible waste, wet paper, fabrics

Cans, bottles, dry paper

To landfill

 

 

Responsibilities for Construction Waste Management

 

8.2.47    The Contractor should incorporate recommendations into a comprehensive on-site waste management plan. This should include all factors dependent on individual works sites including designation of areas for the segregation and temporary storage of materials for future use or recycling. Such provision cannot be specified at this stage.

 

8.2.48    The Fill Management Committee reviews and co-ordinates the provision and operation of public filling facilities. Responsibilities for recycling, re-use or disposal of waste materials are divided between the contractors generating the waste, RSD, and the management of the receiving public filling sites. These responsibilities are described below and summarised in Table 8.4.

 

8.2.49    Under present practices, contractors handle their own wastes, often without separating different types of waste resulting in incorrect disposal of wastes. Under the proposed scheme, contractors would be required to separate wastes to ensure maximum reuse of materials and minimise adverse impact on the environment.

 

Concrete

 

8.2.50    The waste concrete generated during construction should be transported directly to the public filling area by the contractor. Separation is essential to enable concrete to be processed, for example, by crushing at the disposal site, and used as fill at other sites.

 

Wood formwork and steel

 

8.2.51    Only waste material need be taken to the public filling area. It should be separated from recyclable concrete. Contractors are responsible for storage of re-useable materials on site.

Chemical wastes and oil wastes

 

8.2.52    Contractors are responsible for obtaining licences requiring registering as a chemical waste producer with EPD for the disposal of chemical and oil wastes. Chemical wastes should hbe collected by a licensed collector. A storage area should be designated as a pre-disposal containment area to prevent environmental impacts from spilt chemicals.

 

Wheel Wash Waste

 

8.2.53    Areas of sand for absorbing oily wash water should be set up by Contractors. Liaison with RSD is essential for correct disposal.

 

8.2.54    While fulfilling the responsibilities described above, each contractor is required to maintain their works area in compliance with environmental requirements. The generation of dust and noise from concrete and other waste collection must be minimised in compliance with environmental objectives. Maintenance of a clean and tidy environment is essential to minimise adverse environmental and visual impact.

Table 8.4

Responsibilities for waste collection, recycling and

disposal during the Construction Phase

 

Waste type

Responsibility for collection of waste

Responsibility for transport of waste off-site

Responsibility for recycling

Responsibility for disposal

Fill material

Construction contractors required to stockpile excess fill for use elsewhere

Contractor

Recycled on site

Contractor

Concrete

Contractor – directly at source of waste generation

Contractor - in contractor’s vehicles to public filling area

CED (Port Works) defines suitable dumpsites. Project proponent of public filling area is responsible

Contractor

 

Separation of re-useable and waste concrete should be carried out at source by contractor

Disposal of re-useable and waste concrete in different areas of filling area as required

Project proponent to provide different areas for re-useable and waste concrete as required

 

Wood formwork, fencing

Contractor – directly at source of waste generation where volumes are large

Contractor – transported in contractor’s vehicles to public filling area

Contractor - at source

Contractor to Landfill

 

Separation of waste wood and concrete should be carried out at source by contractor

(invert material) or landfill (non-invert material)

 

 

Reinforcing steel, steel cable and shutters

Contractor – directly at source of waste generation where volumes are large

Contractor – transported in contractor’s vehicles scrap/recycling

Contractor - at source

Contractor to scrap/recycling

 

Separation of waste steel and concrete should be carried out at source by contractor

 

 

 

8.3               


8.4              Operational Waste

 

Introduction

 

8.4.1        Assessment of potential solid waste impacts arising from the operation of the Spur Line and stations at Sheung Shui and Lok Ma Chau, involves the following aspects:

 

(i)         A characterisation of the waste generated from the Spur Line once operational.

 

(ii)        The identification of feasible means for the collection, storage and handling of waste generated, for the purpose of disposal of the waste to existing and committed waste management facilities away from the Spur Line.

 

(iii)       The identification and proposal of mitigation measures to ameliorate environmental impacts associated with the operation of the Spur Line and its stations.

 

8.4.2        The types of waste which will arise during the day-to-day operation of the Sheung Shui - Lok Ma Chau Spur Line can be broadly defined as :

 

·                      domestic/municipal waste;

·                      chemical waste; and

·                      screening waste/sludge from sewage treatment plant.

 

Municipal Waste

 

8.4.3        Municipal waste includes domestic waste, commercial waste and industrial waste. Domestic and commercial type wastes will be generated by the public and by employees and commercial operators at the stations. Such waste will include litter, foodstuffs, plastics, wood, office waste, cleaning materials and miscellaneous other waste produced during daily activities.

 

8.4.4        There will be approximately 1100 staff working at Lok Ma Chau Station when it begins operation in 2004. If the quantity of waste produced is assumed to be 1.26kg/employee per day based on the EPD linear regression equation (EPD, 1998), then the total generated waste requiring disposal is approximately 1,386 kg/day. The amount of municipal waste generated by the public using the Spur Line has been calculated based on quantities generated at Lo Wu (information received from KCRC 25 January 2000). Between 1,200kg/day and 2,300kg/day of municipal waste is expected to be generated by passengers at Lok Ma Chau station, depending on passenger flows as estimated in the Implementation Proposal to Government.


8.4.5        Provision of refuse skips, collection of refuse and the ultimate disposal of the refuse to a RTS or landfill will be the responsibility of KCRC and/or the cleaning contractor employed by KCRC.

 

8.4.6        Industrial type waste will arise from maintenance activities on both the railway and the stations and may include spent welding rods, ferrous metals and steel, glass and plastic. Waste generated by maintenance activities may be produced at any point along the alignment rather than at specific locations. Quantities of this type of waste are expected to be small.

 

8.4.7        To prevent industrial and maintenance waste from becoming a nuisance, a licensed waste collector should be employed to remove accumulated waste frequently and dispose of it accordingly. Those components that can be recycled should be separated and arrangements should be made with paper merchants and recycling companies to collect the wastes. A well implemented waste management hierarchy and good practice with respect to storage, transport and disposal, is expected to minimise the potential environmental impacts associated with waste production.

 

Chemical Waste

 

8.4.8        Chemical waste is defined under the Waste Disposal (Chemical Waste ) (General) Regulations as “ Any substance or thing being (a) scrap material, (b) effluent, or (c) an unwanted substance or by-product arising from the application of or in the course of any process in a trade activity, and which is or contains any substance or chemical specified in the prescribed schedule if such substance or chemical occurs in such form, quantity or concentration so as to cause pollution, constitute a danger to health or pose a risk of pollution to the environment.”

 

8.4.9        The main source of chemical waste will be during routine maintenance activities on the railway and the stations. The major chemical waste types arising from the operation of the Spur Line are likely to be lubricants, paints, used batteries, oil, acids and alkalis, pesticides and herbicides, coolants and solvents. Oil waste may be in the form of raw waste or as sundries such as spent oil filters, or materials used to absorb oil leaks.

 

8.4.10    Routine servicing and maintenance of the Air Conditioning (A/C), Air Handling Units (AHU) and chiller plants at stations, in addition to A/C facilities in trains will generate some oil, grease, lubricants, cooler chemicals and germicides. These should not be allowed to discharge to water courses.

 

8.4.11    The use of herbicides and pesticides on the rail tracks and around the stations to prevent the growth of nuisance vegetation, should be minimised to prevent disposal problems and minimise potentially contaminated run-off. Lubricants will also be used on the tracks to ease travel around bends and to reduce noise impacts. This will be magnified at the bends at Sheung Shui and Chau Tau, close to Lok Ma Chau road.

8.4.12    The exact quantities of chemical waste that will be generated by the operation of the Spur Line are unknown at this stage but they are excepted to be small. Due to the potential environmental and health & safety hazard that these chemicals pose, they must be handled, stored and disposed of appropriately, in accordance with the Waste Disposal (Chemical Waste) (General) Regulations and the Code of Practice on Packaging, Labelling and Storage of Chemical Waste. Chemical waste that cannot be recycled should be treated at the Chemical Waste Treatment Centre, Tsing Yi, or at other sites licensed for the disposal of such wastes. Provided that these measures are strictly implemented, no significant impacts are predicted.

 

            Sludge

 

8.4.13    Sludge generated from Lok Ma Chau station will be biologically treated using a sewage treatment plant SWL as a Rotating Biological Contactor (RBC). The incoming raw sewage will first flow into a coarse bar screen to remove large debris prior to pre-treatment. The pre-treated sewage is then pumped at a constant rate to a fine bar screen where small debris is removed. The screenings collected by both the coarse and fine screens will be collected in plastic bags and disposed of as solid waste. Only a small amount of screening waste is expected.

 

8.4.14    Based on the design daily flow of 1,228 m3 per day (with an estimated BOD loading of 760 kg per day) and a sludge yield of 0.45, the amount of waste sludge generated by an RBC is estimated to be around 342 kg per day. The sludge will be treated and dewatered on-site before disposal, using appropriate dewatering equipment to achieve the 30% solids requirement for landfilling. This will reduce the volume of sludge by about 80 percent. Since the amount of sludge generated is not large, the treated sludge can be collected in plastic bags and disposed of as solid waste in landfill or other approved disposal ground. Suitable containers should be provided for the storage of the sludge. Care should be taken to avoid any accidental leakage or spillage of the sludge.

 

Table 8.5

Summary of Potential Waste Types and

Disposal Options during Operational Phase

 

Major Activities

Waste Type

Disposal

Operation of Stations

Sewage

Municipal Waste

Sewage Treatment

Landfill/Recycling

Maintenance of track and stations

Industrial waste

Waste oil and lubricants

Chemical Waste

Landfill/recycling

CWTC*

Licensed contractor

Routine Servicing of A/C, AHU, train carriages etc.

Chemical waste

Waste oil

CWTC

Licensed contractor

Sewage Treatment

Sludge

Landfill or other approved disposal site

 

* Chemical Waste Treatment Centre, Tsing Yi

Recycling or Re-use Facilities

 

8.4.15    Municipal waste recycling is stated to be one of the main requirements to achieve the objectives of the Waste Reduction Study for Hong Kong, which lead to the generation of the Waste Reduction Framework Plan (WRFP) (EPD, 1998). The new stations should be designed to incorporate maximum recycling facilities. Clearly marked out bins should be provided for individual waste types. Eye-catching designs can be used to indicate waste bins to be used for plastics, paper, cans, glass and other waste types. In addition, public awareness of the recycling facilities can be raised through publicity campaigns not only around the stations but also on the trains themselves.

 

8.4.16    This scheme also has financial incentives for KCRC or their appointed waste contractor under the WRFP. The WRFP is expected to introduce taxation measures and charges to waste producers. The costs of waste management will be significantly reduced through the maximisation of recycling process rather than standard disposal routes via RTS or direct to landfill.

 

8.4.17    Re-use of both ferrous and non ferrous metals, wood, oils and other materials used in maintenance of equipment, stations and track should also be incorporated wherever possible. Recycling and waste recovery of such materials should be the next stage where re-use is no longer possible.

 

Responsibilities for Waste Management

 

8.4.18    Responsibility for re-use, recycling or disposal of materials is described below. Once details of location etc. are finalized KCRC should incorporate recommendations of the EIA into a fully comprehensive waste management plan for the SS-LMC spurline.

 

Municipal Waste

 

8.4.19    Under current practices the provision of refuse bins at stations is the responsibility of KCRC and the collection of refuse is the responsibility of their waste/cleaning contractors. Under the WRFP, both parties should take note of Chapter 7: Action for the Private Sector which outlines ways of reducing waste and managing it more efficiently.

 

8.4.20    Arrangements should be made with recycling companies for the collection of paper, plastics, glass and all other recycled materials.

 


Chemical Waste

 

8.4.21    The contractors involved in the servicing and maintenance of the air conditioning, air handling unit and chiller plant are responsible for obtaining licences for the handling, storage and disposal of chemical and oil wastes. If required, a storage area should be designed as a pre-disposal containment area to prevent environmental impacts from these chemicals.

 

Sludge

 

8.4.22    The ultimate responsibility of the sewage treatment plant will be the users (KCRC or an appointed contractor). Sludge generated from the treatment of sewage should be treated and properly stored on site and disposed of at a designated landfill or other approved site.

 

Other Projects in the Study Area

 

8.4.23    The recently publicized Kwu Tung SGA under the NENT Planning Study will also have impacts on waste production in the area. The findings of the Spur Line EIA should be taken into account in the EIA for the SGA, to minimize environmental impacts.

 

8.5              SUMMARY

 

8.5.1        A variety of waste materials will be generated during construction and operation of the Spur Line. Waste types and quantities have been estimated as far as possible and mitigation measures evaluated in terms of the avoidance-minimization-recycling-disposal hierarchy recommended by Government.

 

8.5.2        Construction phase waste includes material from excavation of fishponds and blasted rock during construction of cuttings. Inert materials such as concrete and steel should be separated from excavated earth and wooden formwork which can be re-used on site during the filling processes, in particular at Lok Ma Chau Station. It is likely that all suitable excavated material for filling can be used within the alignment boundary. Some additional fill material may be required for Lok Ma Chau station.

 

8.5.3        Good working practices will minimize potential impacts which arise from the production of waste. Measures which should be taken are described below:

 

i)          Stockpiles should be protected from erosion.

 

ii)         Vehicles carrying unsuitable material should have their loads covered and be routed to avoid sensitive receivers.

iii)         Wastewater should be appropriately collected and treated.

 

iv)        Chemicals should be correctly stored and recycled where possible.

 

v)         Recycling should be practiced wherever possible.

 

vi)        All wastes should be collected at regular intervals to keep the site tidy.

 

8.5.4        In addition, the following steps will be taken to ensure waste characterisation and quantification on site:

 

i)                    KCRC, or the main contractor, should act as the overall coordinator for the management of waste. It is important as it can minimize the disposal of C&DM off-site, especially there is opportunity for the transfer or excavated material from one portion to another portion of the project. An overall waste management plan should be prepared by this party and submitted to EPD for review and incorporation of his comments into the WMP to his satisfaction before the commencement of construction is required.

 

ii)                   the contractor shall record the amount of waste-generated, recycled and disposed of (including the disposal sites).

 

iii)                 the contractor shall use a trip ticket system in accordance with WBTC 5/99 for the disposal of C&D materials to any designated public filling facility and/or landfill.

 

iv)                 training shall be provided for workers about the concepts of site cleanliness and appropriate waste management procedure, including waste reduction, reuse and recycling.

 

8.5.5        During operation, the main wastes generated will be domestic refuse and sludge from the sewage treatment plant on site. Refuse should be collected through an appropriate system of waste disposal facilities, with recycling implemented where feasible. Sludge will be dewatered before disposal to landfill. Chemical wastes require correct storage, handling and disposal to minimize potential impacts on the environment.

 

8.5.6        Implementation of an efficient waste management strategy based on the recommendations provided in this chapter will minimize potential impacts from the generation storage, handling, transport and disposal of wastes arising from the Spur Line Project.

 

 


REFERENCES

 

ProPECC Paper PN 1/94 Environmental Protection Department Practice note for Professional Persons: Construction Site Drainage.

 

EPD (1998). Waste Reduction Framework Plan, 1998-2007. Planning, Environment and Lands Bureau.

 

EPD (1992). Code of Practice on one Packaging, Labelling and Storage of Chemical Wastes.