5.                  WASTE MANAGEMENT


5.1              Introduction


This section identifies the potential wastes arising from the construction of the Link Roads G & L and provides an assessment of the potential environmental impacts associated with the handling and disposal of these wastes.


It is anticipated that only a small amount of waste will be generated during the operational phase of the Link Roads G & L as discussed in Sections 5.4 and 5.5.  It is therefore concluded that the potential environmental impacts associated with waste management during the operational phase will not be a concern and hence a detailed waste management impact assessment is not required.


The options for reuse, minimisation, recycling treatment, storage, collection, transport and disposal of wastes arising from the Project have been examined.  Where appropriate, procedures for waste reduction and management are considered and environmental control measures for avoiding and minimising the potential impacts are recommended.


5.2              Environmental Legislation and Standards


5.2.1    Legislation


The following legislation encompasses the storage, collection treatment and disposal of the wastes arising from the Project:


•           Waste Disposal Ordinance (Cap 354);

•           Waste Disposal (Chemical Waste) (General) Regulation (Cap 354);

•           Land (Miscellaneous Provisions) Ordinance (Cap 28); and

•           Public Health and Municipal Services Ordinance (Cap 132)-Public Cleansing and Prevention of Nuisances (Urban Council) and (Regional Council) By-laws.


5.2.2    Guidelines


The following documents, guidelines and circulars provide guidance on waste management as follows:


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

•           Environmental Guidelines for Planning in Hong Kong (1990), Hong Kong Planning and Standards Guidelines, Hong Kong Government;

•           New Disposal Arrangements for Construction Waste (1992); Environmental Protection Department & Civil Engineering Department;

•           Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), Environmental Protection Department;

•           Work Branch Technical Circular No. 6/92, Fill Management

•           Works Branch Technical Circular No. 2/93, Public Dumps;

•           Works Branch Technical Circular No. 16/96, Wet Soil in Public Dumps; and

•           Works Bureau Technical Circular No. 5/98, On-site Sorting of Construction Waste on Demolition Site.


5.3              Assessment Methodology


5.3.1    General


The potential environmental impacts due to the management of the wastes arising from the Project have been assessed in accordance with the criteria presented in Annexes 7 and 15 of the EIAO-TM and are summarized as follows:


•           estimation of the types and quantities of the wastes to be generated;

•           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.


5.4              Construction Waste Impact


5.4.1    Potential Sources of Impact


The Link Roads G & L will involve the construction of the following main structures;

•           Link Roads G and L at Lai Wan Interchange;

•           Northbound Upramp to Prince Roundabout & Section of Road P1C(S/B) below Prince Edward Roundabout;

•           Road NR14; and

•           Associated utilities including watermains, drains and sewers.


The construction activities to be carried out for the proposed developments will result in the generation of a variety of wastes which may include:


•           site clearance waste;

•           excavated materials;

•           construction and demolition (C&D) waste;

•           chemical waste; and

•           general refuse.


If not properly managed, the handling and disposal of these wastes may cause adverse environmental nuisance and impacts.  The nature of each of these wastes are discussed below.


5.4.2    Site Clearance Waste


Link Roads G & L will largely consist of viaducts which will require limited site clearance works related to small volumes of general refuse, concrete and soil.


5.4.3    Excavated Materials


As indicated in the preliminary construction programme, the majority of excavated materials will be generated from the following activities:


•           Construction of the foundations for the viaducts; and

•           Earthworks excavation;


The excavated materials will mainly consist of inert soil which could be reused on site as fill materials.


5.4.4    Construction and Demolition Waste


Construction and demolition (C&D) material will mainly be generated from construction of the viaducts. C&D material may include:


•           wood from formwork and falsework;

•           materials and equipment wrappings;

•           unusable/surplus concrete/grouting mixes; and

•           damaged/contaminated/surplus construction materials


5.4.5    Chemical Waste


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.  Chemical wastes are expected to mainly be generated through maintenance of equipment and may include:


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

•           used engine oils hydraulic fluids and waste fuel;

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

•           spent solvents/solutions, some of which may be halogenated, from equipment clearing activities.


Hazards associated with the improper handling, storage or disposal of chemical wastes may include:


•           toxic effects to workers;

•           fire hazards; and

•           possible disruption of sewage treatment works if chemical waste enters the sewerage system.


5.4.6    General Refuse


It is estimated that a maximum of 100 workers will be working on-site during the peak construction period.  General refuse including paper and food waste will be generated from the work site.  The storage, handling and disposal of general refuse have the potential to give rise to adverse environmental impacts if not properly managed.  These include odour if waste is not collected frequently, windblown litter, and visual impact.  This work site may also attract pests and vermin if the waste storage areas are not well maintained and cleaned regularly.  In addition, disposal of waste at sites other than approved waste transfer or disposal facilities, could also have adverse impacts.


5.5       Evaluation of Impacts


The construction of Link Roads G & L is scheduled to commence in June 2001 and finish by the end of June 2003.  The amount of waste arising from the construction activities and the potential environmental impacts associated with the handling, storage, transport and disposal of these wastes are discussed below.


5.5.1    Site Clearance Waste


The major construction works of Link Roads G & L is in the form of viaducts, the amount of site clearance works will be limited.  The site clearance waste is expected to consist of general refuse and concrete.  It is considered that the handling and disposal of small amount of the site clearance waste will not be a key issue and the potential environmental impacts associated with the handling and disposal of site clearance waste will be negligible, subject to the implementation of the recommended mitigation measures in Section 5.6.


5.5.2    Excavation Material


With respect to the nature and scale of the excavated works, the majority of the excavated material will arise from the earthworks excavation and construction of the foundation for the viaducts.


It is estimated that about 1,000m3 excavated materials will be generated as a result of these works.  A total of 40,000m3 of general fill will be required for the site formation and construction of road embankments.  It means that the general fill materials required cannot be fully supplied by the excavated materials on-site, and 39,000m3 of fill material will need to be imported to site.


The majority of the excavated materials will be reused on-site as fill materials for site formation and construction of road embankments. As discussed above, fill material is required to import from other current construction site nearby so that on-site stockpilling of fill material may be required.  With respect to the proposed construction programme, the cut and fill activities will be co-ordinated so that the need for on-site storage of fill material will be minimised.  The temporary stockpiling areas will be located at Link Roads G & L.  However, to eliminate the risk of the excavated materials blocking this main drainage channel during the west season, it is proposed that stockpiling of fill materials during wet season should be avoided as far as practicable.  Mitigation measures to control surface runoff from the temporary stockpilling area have been recommended in Section 5.6.4.  Opportunities for use of fill at nearby construction sites should be explored to minimise vehicle movements in the area.


The excavation work will be carried out over approximately 4 months.  The average quantity of fill material to be imported on a daily basis will be about 325m3.  Based on a payload of 6.7m3 per truck, the additional traffic to be generated due to transportation of fill material will be about 54 truck trips per day.  It is considered that this small contribution of traffic will not cause an adverse impact on local traffic.


The potential noise impacts due to on-site storage and transport of fill have been evaluated in Section 4.  The potential air quality impacts due to the emission of dust from the haulage of excavated materials by trucks are expected to be minimal due to the small number of vehicles involved.  Provided the mitigation measures suggested in Section 5.6 are carried out, the potential dust impacts as expected to be minimal.


5.5.3    Construction and Demolition Waste


The quantity of C&D material arising from the construction of the proposed route will be about 1000m3.  Options for reuse should be explored.


C&D material should be sorted at work site before disposing of inert materials (public fill) at public filling areas and non-inert or putrescible materials (wood, paper, plastic, etc), ie C&D waste at landfills.  C&D material should be removed from site as soon as practicable.


To conserve void space at landfill sites, C&D waste with more than 20% (by volume) inert material (dust, dirt, soil, brick, ceramic tiles, concrete, etc) should not be disposed at landfills, but should be reused wherever possible.


5.5.4    Chemical Waste


It is difficult to quantify the amount of chemical waste generated as this will depend on the Contractor’s on-site maintenance practice.  However, it is anticipated that the quantity of  chemical waste, such as lubricating oil and solvent, produced from plant maintenance will be relatively small. These types of waste will be readily accepted at the Chemical Waste Treatment Centre at Tsing Yi.  Waste oil could also be delivered to other licensed facilities for recycling.


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 Waste published by the EPD.  Provided that this occurs, and the chemical waste is disposed of at a licensed chemical waste treatment and disposal facility, the potential environmental impacts arising from the storage, handling and disposal of a small amount of chemical waste generated from the construction activities will be negligible.


5.5.5    General Refuse


It is estimated that there will be about 100 workers working on-site during the peak construction period.  The quantity of general refuse to be generated from the construction workforce is estimated to be about 110 kg per day if the quantity of municipal waste generated is estimated to be 1.1 kg/employee/day (Source: Monitoring of Solid Waste in Hong Kong 1998 published by Environmental Protection Department).  Provided good practice with respect to storage, transport and disposal as presented in Section 5.6 is adhered to and the refuse is disposed of to landfill then environmental impacts will be minimal.


5.6       Mitigation Measures


5.6.1    Introduction


This section sets out recycling, storage, transportation and disposal measures which are recommended to avoid or minimise potential adverse impacts associated with waste arising from the construction of the Link Roads G & L.  The recommendations should be incorporated into an on-site waste management plan for the construction works by the Contractor.  The waste management plan should incorporate site specific factors, such as the designation of areas for the segregation and temporary storage of reusable and recyclable materials.


It is the Contractor’s responsibility to ensure that only approved licensed waste collectors are used and that appropriate measures to minimise adverse impacts, including windblown litter and dust from the transportation of these wastes are employed.  In additional, the Contractor must ensure that all the necessary waste disposal permits are obtained.


5.6.2        Waste Management Hierarchy


Various waste management options are as follows:


•           avoidance and minimisation, ie not generating waste through changing or improving practices and design;

•           reuse of materials, thus avoiding disposal (generally with only limited reprocessing);

•           recovery and recycling, this avoiding disposal (although reprocessing may be required); and

•           treatment and disposal, according to relevant laws, guidelines and good practice.


This hierarchy should be used to evaluate waste management options, thus allowing waste reduction measures to be introduced at the detailed design stage and carried through to the construction phase.


Training and instruction of construction staff should be given at the site to increase awareness and draw attention to waste management issues and the need to minimise waste generation.  The training requirement should be included in the site waste management plan.


5.6.3    Storage, Collection and Transport of Waste


Permitted waste hauliers should be used to collect and transport wastes to the appropriate disposal points.  The following measures to minimise adverse impacts should be instigated:


•           handle and store wastes in a manner which ensures that they are held securely without loss or leakage, thereby minimising the potential for pollution.

•           use waste hauliers authorised or licensed to collect specific category of waste;

•           remove wastes on a daily basis;

•           maintain and clean waste storage areas daily;

•           minimise windblown litter and dust during transportation by either covering trucks or transporting wastes in enclosed containers;

•           obtain the necessary waste disposal permits from the appropriate authorities, if they are required, in accordance with Waste Disposal Ordinance (Cap 354), Waste Disposal (Chemical Waste) (General) Regulation (Cap 354), the Land (Miscellaneous Provisions) Ordinance (Cap 28);

•           Dispose of waste at licensed waste disposal facilities

•           Develop procedures such as ticketing system to facilities tracking of loads, particularly for chemical waste, and to ensure that illegal disposal of wastes does not occur, and

•           Maintain records of the quantities of wastes generated, recycled and disposal.


5.6.4    Excavated/Imported Filling Material


            The excavated/imported filling material may have to be temporarily stockpiled on-site for the construction of road embankment and foundation of viaduct substructure.  Control measures should be taken at the stockpilling area to prevent the generation of dust and pollution of stormwater channels.  However, to eliminate the risk of blocking drains in the wet season, it is recommended that stockpiling of excavated materials at during wet season should be avoided as far as practicable.


Dust :


•           wetting the surface of the stockpiled soil with water when necessary especially during the dry season;

•           covering the stockpiled soil with sheets;

•           minimising disturbance of the stockpiled soil; and

•           enclosure of stockpiling area.

Water Quality:


•           installation of silt traps for the surface water drainage system; and

•           covering stockpiled material with trapaulin during heavy rainstorm.


            In addition, potential dust impacts due to the haulage of excavated/imported filling materials should be minimised by undertaking the following control measures:


•           dropping heights for those materials should be controlled to a practical height to minimise the fugitive dust arising from unloading;

•           materials should not be loaded to a level higher than the side and tail boards, and should be dampended or covered before transport.

•           the travelling speed should be reduced to 10 km hr-1 to reduce dust dispersion and re-suspension from the operating haul trucks;

•           wheel washing facilities should also be installed and sued by all vehicles leaving the site.


5.6.5    Construction & Demolition Waste


In order to minimise waste arisings and to keep environmental impacts within acceptable levels, environmental control measures as described are recommended.


Careful design, planning and good site management can minimise over-ordering and generation of waste materials such as concrete, mortars and cement grouts.  The design of formwork should maximise the use of standard wooden panels so that high reuse levels can be achieved.  Alternatives such as steel formwork of plastic facing should be considered to increase the potential for reuse.


The Contractor should recycle as much of the C&D material as possible on-site.  Proper segregation of wastes on site will increase the feasibility of certain components of the waste stream by the recycling contractors. 


Government has established a charging scheme for the disposal of waste to landfill.  When it is implemented, this will provide additional incentives to reduce the volume of waste generated and to ensure proper segregation of wastes to allow free disposal of inert material to public filling areas.


5.6.6    Chemical Waste


For those processes which generate chemical waste, it may be possible to find alternatives which generate reduced quantities or even no chemical waste, or less dangerous types of chemical waste.


Chemical waste that is produced, as defined by Schedule 1 of the Waste Disposal (Chemical Waste) (General) Regulation, should be handed in accordance with the Code of Practice on the Packaging, Handling and Storage of Chemical Waste as follows:


            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 litres unless the specification 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 should:


•           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 as chemical waste if necessary); and

•           be arranged so that incompatible materials are adequately separated.


Disposal of chemical waste should:


•           be via a licensed waste collector; and

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

•           to be reuser of the waste, under approval from the EPD.


The Centre for Environmental Technology operates a Waste Exchange Scheme which can assist finding receivers or buyers for the small quantity of chemical waste to be generated from the project. 


5.6.7    General Refuse


General refuse should be stored in enclosed bins or compaction units separate from C&D and chemical wastes.  The Contractor should employ a reputable waste collector to remove general refuse from the site, separate from C&D and chemical wastes, on a regular basis to minimise odour, pest and litter impacts.  Burning of refuse on construction sites is prohibited by law.


General refuse is generated largely by food service activities on site, so reusable rather than disposable dishware should be used if feasible.  Aluminum cans are often recovered from the waste stream by individual collectors if they are segregated or easily accessible, so separate labelled bins for their deposit should be provided if feasible.


5.7       Environmental Monitoring and Audit Requirements


It is recommended that auditing of each waste stream should be carried out periodically to determine if wastes are being managed in accordance with approved procedures and the site waste management plan.  The audits should look at all aspects of waste management including waste generation, storage, recycling, treatment, transport and disposal.  An appropriate audit programme would be undertake a first audit at the commencement of the construction works should be defined as the commencement of any related physical activity undertaken within the site boundary.


5.8       Conclusions


The potential environmental impacts with the handling and disposal of waste arising from the construction of Link Road G & L have been assessed.  Operational impacts on the proposed route are not expected to be a key concern and no detailed assessment will be required.  Key issues include the need for effective waste management planning during the construction phase.  The assessment has concluded that the potential environmental impacts associated with the handling, storage, treatment and disposal of waste arising for the construction of Link Roads G & L meet the requirements of the EIAO-TM.