This section of the EIA report summarises the assessment of the potential environmental impacts caused by the wastes generated during the construction and operation of the proposed works and recommends an appropriate disposal strategy to alleviate the identified potential impacts. The recommended Disposal Strategy is based upon the waste management principle to reduce the amount of waste for disposal through the development of outline plans for waste avoidance, material re-use and recycling. It was focuses upon the tenets contained within the “Environmental Code of Practice for Construction of the Tung Chung Cable Car Project” MTRC, October 2002, refer to Section 12 for details.
Mitigation measures are proposed to alleviate the impacts caused by the excavated materials and residual wastes during their handling, temporary storage on site, transportation and final disposal. The key task of the waste management assessment is to determine the types possible, and, where possible, estimate the quantities of all solid waste arising during the construction for determining the most appropriate methods of treatment, handling and disposal. It is also essential to understand the nature and composition of the wastes, in particular whether the waste materials are inert or contaminated for allocating the appropriate disposal route.
Wastes generated during the operational phase relate to domestic sewage from the toilets of the terminals and general waste papers, cars etc. The latter will be disposed of using good housekeeping measures and the former will be disposed of via foul sewers.
The overall objectives for the liquid and solid waste management assessment are to:
1. identify the construction activities involved for determining the types, nature and quantities of waste generated;
2. identify any potential environmental impacts caused by the wastes generated from the proposed works;
3. categorise waste materials where practical, i.e. suitability for re-use/recycling, disposal to public filling areas, disposal to landfill and any pre-treatment requirements prior to disposal;
4. assess and evaluate appropriate waste management options (including waste minimisation on-site, re-use or recycling opportunities and off-site disposal options);
5. recommend appropriate management/mitigation measures that should be implemented to minimise the identified impacts during the generation, handling, storage;
6. set up appropriate routes for waste disposal, in accordance with the current legislative and administrative requirements; and
7. identify the possible sites for dumping.
The legislation on handling, treatment and disposal of wastes, which are of relevance to this Project, are:
· Waste Disposal Ordinance (Cap. 354) & relevant regulations;
· The Land (Miscellaneous Provisions) Ordinance (Cap 28);
· Environmental Impact Assessment Ordinance (Cap. 499);
· Public Health and Municipal Services Ordinance (Cap. 132);
· Waste Reduction Framework Plan (WRFP); and
· Works Technical Circulars (for reference purposes only).
Waste Disposal Ordinance (Cap. 354) and relevant regulations
The Waste Disposal Ordinance (WDO) enacted in 1980 provides the statutory framework for the management of all wastes from where they arise to the point of final disposal i.e. control on the collection, treatment and disposal of waste. The WDO prohibits any person from using any land or premises for the disposal of wastes unless the person has been authorised by or has obtained a license from the waste disposal authority. The ordinance was amended in early 1995 to enable permit control on import and export of wastes in line with the requirements under the Basel Convention, and was in place in September 1996. The ordinance was further amended in early 1997 to enable more effective implementation of waste disposal charging.
There are a number of provisions under the WDO for dealing with certain types of waste. These include the Waste Disposal (Chemical Waste) (General) Regulation (CWR). This Cradle-to-grave control of chemical wastes was implemented in May 1993 to control all aspects of chemical waste disposal, including packaging, labelling, storage, collection, transport, treatment and final disposal. Under the CWR, any person who produces or causes to produce chemical waste must register with the Environmental Protection Department (EPD). Each registered producer has the obligation to inform the EPD as soon as practicable of any change in the particulars of the registration. The CWR requires waste producers to arrange for proper disposal of their wastes at licensed facilities and to engage a licensed collector to remove and transport the waste. It also requires that all chemical waste must be properly stored, packaged and labelled.
The Land (Miscellaneous Provisions) Ordinance (Cap 28)
Requires that dumping licences are obtained by individuals or companies who deliver suitable construction wastes to public fills, public filling barging points or public fill stockpiled areas. Under the licence conditions public dumps will accept only inert building debris, soil, rock and broken concrete.
Environmental Impact Assessment Ordinance (Cap. 499)
Designated projects specified under Schedule 2 of the EIAO must follow the statutory EIA process and apply for environmental permits for their construction and operation. Annex 7 of the TM under the EIAO specifies the assessment criteria for evaluating waste management implications.
Public Health and Municipal Services Ordinance (Cap. 132)
Public Health and Municipal Services Ordinance provides for the control of the discharge of hazardous materials to sewers, and for the control of littering. It also places restrictions on the storage of wastes in buildings. This may be applicable to construction site offices.
A Waste Reduction Framework Plan (WRFP)
The WRFP sets out programme to avoid and minimise waste; promote recovery, recycling and reuse of materials; prolong the life of existing landfills and reduce the increasing costs of waste transportation, treatment and disposal.
Works Bureau Technical Circulars (used for a reference but not a requirement)
Works Bureau Technical Circular No. 2/93 - Public Dumps and the Works Bureau Technical Circular No. 2/93B - Public Filling Facilities
The Technical Circular outlines the policy relating to dumping of Construction and Demolition (C&D) waste. The circulars state the C&D material suitable for use as fill material should not be disposed of to landfills, but should be reused in public filling area or reclamation and land formation projects. The Public Filling Sub-Committee together with Project Departments are responsible for considering the suitability of a site as a public filling area. In order to dispose of the inert portion of C&D material in a public filling area, a license issued by the Civil Engineering Department is required.
Works Bureau Technical Circular No. 21/2002 - Trip-ticket System for Disposal of Construction and Demolition Material
This Circular supersedes WBTCs No. 5/99 and 5/99A and promulgates the auditing requirements for the implementation of the trip-ticket system in PWP contracts for proper disposal of construction and demolition (C&D) material at public filling facilities or landfills.
The Works Bureau Technical Circular No. 25/99, 25/99A and 25/99C
Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers promulgates the policy and guidelines for incorporating information on the management of construction and demolition material in Publics Works Subcommittee papers recommending the upgrading of projects to Category A of the Public Works Programme for the implementation of construction works.
The Works Bureau Technical Circular No. 29/2000 - Waste Management Plan
The Technical Circular requires contractors to prepare and implement a Waste Management plan (WMP). The requirement should be included in all PWP contracts (including design and build contracts but excluding term contracts and contracts administered by Electrical and Mechanical Services Department).
Works Bureau Technical Circular No. 4/98 and No. 4/98A – Use of Public Fill in Reclamation & Earth Filling Projects
Works Bureau Technical Circular No. 19/2001 – Metallic Site Hoardings and Signboards
Works Bureau Technical Circular No. 12/2000 – Fill Management
The assessment of the environmental impacts from the handling, storage, collection, transportation and disposal of waste material (liquid and solids) generated by the project has been undertaken in accordance with Annex 7 and Annex 15 of the TM.
The waste management hierarchy has been applied in the assessment and development of mitigation measures for waste. The waste management hierarchy is a concept which shows the desirability of various waste management methods and comprises the following in order of preference:
· avoidance;
· minimisation;
· recycling/reuse;
· treatment; and
· disposal.
All opportunities for reducing waste generation have been assessed based upon the following factors:
· avoiding or minimising waste generation through changes in the design;
· adopting better management practices to promote segregation of waste materials;
· reuse and recycling; and
· diverting waste to public dumps or other construction sites.
The types and quantities of waste have been estimated and disposal options for each category of waste identified, taking into account the existing or future spare capacities of the waste disposal facilities and the environmental implications of the handling, collection and disposal of waste material.
The existing waste management issues within the study area generally relate to refuse from the residential properties at Ngong Ping and Tung Chung and users of the Country Park. This waste is collected and deposited at the North Lantau Refuse Transfer Station(s) before transfer to a licensed landfill for ultimate disposal (such as the WENT Landfill). These facilities also handle construction and demolition waste from Lantau Island with any material suitable for public fill being deposited at the public fill stockpile area in Mui Wo. Both refuse transfer stations have spare daily capacity, with the North Lantau facility having significant capacity for further throughput.
Wastes which are likely to be generated during the construction of the angle stations, towers and termini include the following:
· vegetation and topsoil removed from site clearance around the tower locations although wherever possible this will be re-used on-site especially at the tower locations;
· construction and demolition material;
· excavated materials;
· chemical waste material; and
· municipal wastes.
During the construction phase, waste containers will be situated at:
· Tung Chung Terminal;
· Airport Angle Station;
· Nei Lak Shan Angle Station; and
· Ngong Ping Terminal.
The waste accruing at the Angle Station may be brought:
· manually to Ngong Ping or near San Tau (carried by construction workers);
· by the material ropeway (although this method of construction is not favoured); and
· by helicopter.
The waste disposal routes using helicopters is shown in Figure 6.1. The material generated at the tower locations will be transported to the Angle Station for collection by helicopter for transport to either the Temporary Depot (near Airport) or Ngong Ping Storage Place and transported by truck to the official waste depot.
The waste disposal route using the material ropeway is shown in Figure 6.2. The material generated will be transported by the material ropeway to Ngong Ping terminal, Angle Station (temporarily) or near San Tau and transported by truck to the official waste depot.
According to the Environmental Impact Assessment Study Brief No. ESB- 068/2001 all construction materials and wastes to and from the work sites within the Country Parks shall be transported by helicopter unless it is shown to be impracticable. No haul road shall be formed to access the work sites within the Country Park(s).
The estimated vegetation required for removal from the site clearance at the following locations are shown below in Table 6.1 (refer to Table 7.21 in Section 7).
It is anticipated that grassland material cleared will not require disposal off-site as the amount generated is considerably less than that of other vegetation communities. Grassland and low shrub communities are anticipated to generate very low amounts of vegetation and are anticipated to be fully utilised for landscaping purposes on site (refer to Section 7.8.2).
Table 6.1 Vegetation Removed from Site Clearance (Approximate)
|
Habitat |
Description and Location (and Totals) |
Study Area (permanent loss) (ha) |
Study Area (temporary loss) (ha) |
Total |
|
Grassland |
Nei Lak Shan Angle Station |
0.20 |
0.26 |
0.46 |
|
|
Tower 6 |
0.01 |
0.13 |
0.14 |
|
|
Emergency Rescue Trail |
0.30 |
0.03 |
0.33 |
|
|
Touch Down Point (3) |
0.00 |
0.10 |
0.10 |
|
|
Total HC |
0.51 |
0.52 |
1.03 |
|
|
Total MRC |
0.00 |
0.03 |
0.03 |
|
|
Total |
0.51 |
0.55 |
1.06 |
|
Low shrub |
Tower 3 |
0.01 |
0.13 |
0.14 |
|
|
Tower 4 |
0.01 |
0.13 |
0.14 |
|
|
Tower 5 |
0.01 |
0.13 |
0.14 |
|
|
Tower 7 |
0.01 |
0.13 |
0.14 |
|
|
Ngong Ping Terminal |
0.30 |
0.09 |
0.39 |
|
|
Emergency Rescue Trail |
0.30 |
0.03 |
0.33 |
|
|
Total HC |
0.64 |
0.64 |
1.28 |
|
|
Total MRC |
0.00 |
0.01 |
0.01 |
|
|
Total |
0.64 |
0.65 |
1.29 |
|
Developed area |
Tung Chung Terminal |
1.50 |
0.25 |
1.75 |
|
|
Tower 1 |
0.01 |
0.13 |
0.14 |
|
|
Airport Island Angle Station |
0.30 |
0.06 |
0.36 |
|
|
Tower 2A |
0.01 |
0.13 |
0.14 |
|
|
Tower 2B |
0.01 |
0.13 |
0.14 |
|
|
Emergency Rescue Trail |
0.02 |
0.01 |
0.03 |
|
|
Total HC |
1.85 |
0.71 |
2.56 |
|
|
Total MRC |
0.00 |
0.00 |
0.00 |
|
|
Total |
1.85 |
0.71 |
2.56 |
|
Plantation |
Airport Island Angle Station |
0.30 |
0.06 |
0.36 |
|
Stream |
Ngong Ping Terminal |
0.00 |
30m* |
30m* |
|
Tall shrub |
Emergency Rescue Trail |
0.09 |
0.01 |
0.10 |
|
|
Total HC |
0.09 |
0.01 |
0.10 |
|
|
Total MRC |
0.00 |
0.03 |
0.03 |
|
|
Total |
0.09 |
0.04 |
0.13 |
|
Woodland |
Emergency Rescue Trail |
0.03 |
0.09 |
0.12 |
|
|
Total HC |
0.03 |
0.09 |
0.12 |
|
|
Total MRC |
0.00 |
0.00 |
0.00 |
|
|
Total |
0.03 |
0.09 |
0.12 |
|
Total HC |
|
3.42 |
2.03 |
5.45 |
|
Total MRC |
|
0.00 |
0.07 |
0.07 |
|
Total Loss |
|
3.42 |
2.10 |
5.52 |
Note: MRC: Material Ropeway Construction
HC: Helicopter Construction
*: Indicates the approximate length of the stream that will be disturbed
The values provided in this table are based on the tower base size, terminal location, Angle stations and their respective anticipated construction area. The figures listed are provided as an approximate indication of the potential habitat loss. The areas have been calculated from the proposed construction areas while the Emergency Rescue Trail has been calculated from Figure 7.3.
Source: Information adapted from MTRC Land Use Map and Figure 7.3
C&D material may contain a mixture of inert and non-inert material. The inert portion can be used as public fill for dumping in public filling areas whilst the non-inert portion is classified as C&D waste which will require to be disposed of at a landfill site.
The construction of the termini at Ngong Ping will require some breaking up of hard paving to accommodate the construction works for the building.
Construction and demolition materials arising from the construction may include: -
· waste timber formwork;
· spent concrete and cement screening, very minimal; and
· material and equipment wrappings.
The proposed Tung Chung terminal is sited on previously reclaimed land and the Ngong Ping terminal site is currently on low shrubland. It is anticipated that approximately 5255m3 of excavated material will be removed from the terminals, approximately 540m3 for towers and 300m3 for the angle stations and will require disposal only as a last resort.
It is the intention to reuse all the material on site and it is predicted that only a negligible quantity of unsuitable material (material which is waterlogged or not of a suitable grade) will have to be transported off-site to a public fill facility.
Plant and vehicle servicing will likely be the primary source of chemical wastes during the construction period. The majority of chemical waste produced is therefore expected to consist of waste oils and solvents. Typical wastes may include the following:
· solid wastes (empty fuel/lubricant drums, used oil/air filters, scrap batteries, vehicle parts); and
· liquid wastes (waste oils/grease, spent solvents/detergents and possibly spent acid/alkali from batteries maintenance).
The volume of chemical waste will depend upon the total number of plant/ vehicles and how much maintenance is actually carried out on site. However volumes are expected to be less than approximately 50 litres a month. It is anticipated that some lubricating oils will be generate as part of the operational wastes produced off-site.
Workers will generate municipal wastes such as food wastes, packaging and wastepaper. For estimating the quantity of municipal wastes, EPD’s average value 1.07kg/employee/day has been adopted (Monitoring of Municipal Solid Waste 1996, EPD (1997) Hong Kong Government).
The total volume of waste generated depends on the number of workers to be employed on site. It is anticipated that the maximum number of workers and site staff to be employed at peak times is less than 100 (assume 4-6 at each tower location and 30 at each terminal). Considering 6 working days per week, the amount of municipal waste generated will be around 600kg/week (maximum). Disposal will be the responsibility of the Contractor who shall in accordance with general avoidance of nuisances measures (required under the Contract) remove material at such a frequency to avoid nuisance. No wastes will be allowed to be left in the Country Park and Water Gathering Grounds and no oil/flammable etc materials will be able to be stored overnight except at the terminals or work sites.
The estimated sewage arising from the workforce during the construction phase will be 6.0m3/day according to the Sewerage Manual (Part 1), Drainage Services Department, 1995. Facilities such as mulching or chemical toilets (disposal off-site) will need to be provided especially at each of the tower locations and measures taken to ensure the use of maintenance to ensure no sewage is allowed to be discharged directly into receiving environment. With the provision of such sanitary facilities and implementation of proper management and cleaning procedure, no adverse impact is envisaged on receiving environment. The flow and loads caused by the construction workforce and the result are presented in the following Table 6.2.
Table 6.2 Estimated Flow and Loads Caused by the Construction Workforce
|
Flow (m3/d) |
SS (kg/d) |
BOD (kg/d) |
COD (kg/d) |
TKN (kg/d) |
NH3N (kg/d) |
E.Coli (no./d) |
|
6.0 |
3.4 |
3.4 |
7.0 |
0.670 |
0.4 |
3.5x1012 |
Provision of the emergency rescue trail is expected to be undertaken using handheld tools. The trail will be a maximum of 1.5m wide and may require digging a shallow narrow trench to lay systems cables. The excavated material estimated to be will be backfilled and as such there will be no soil exported offsite. Vegetation which is cleared will be collected and reused onsite or in the vicinity of the site so will not be any waste arising as described in Section 7 (Ecology). There will be no net waste arising as a result of providing this emergency rescue trail.
The construction programme is expected to extend between (August 2003 to August 2005). The estimated types and volumes of waste generated have been identified and are summarised in Table 6.3.
Table 6.3 Summary of Wastes to be Generated
|
Material Type |
Likely Time of Arising |
Estimated Total Volumes Generated and Disposal of Wastes |
|
|
Tower and Angle Station Construction |
|
||
|
Vegetation and excavated topsoil. |
During tower platform and Angle Station formation. |
· Vegetation cleared approximately 10m3 for the towers and angle stations to be reused on site. · Excavated topsoil to be reused on site approximately 400m3 for Tower locations and 200m3 for the angle stations.
|
|
|
Excavation soil/ rock (surplus materials to be disposed of as public fill).
|
Excavation of foundations. |
· Approximately 550m3 for the tower locations and 300m3 for the angle station locations. |
|
|
Municipal wastes – packing materials etc.
|
During the erection of the towers and Angle Stations.
During all stages of construction.
|
· Municipal wastes and other general wastes will be approximately 60m3 for the tower locations and 300m3 for the angle station locations.
|
|
|
Chemical wastes- Paints, solvents fixatives.
|
During the erection of the towers and Angle Stations. |
· The chemical, wastes, paints solvents etc used is assumed to be 50L /month* for the entire site. |
|
|
Emergency Rescue Trail |
|
||
|
Vegetation and excavated topsoil. |
Site clearance. |
· Vegetation cleared approximately 50m3 to be reused on site.
|
|
|
Termini Locations |
|
|
|
|
Vegetation and excavated topsoil. |
During terminal buildings formation. |
· Vegetation cleared approximately 15m3 to be reused on site. · Excavated topsoil to be reused onsite approximately 625m3.
|
|
|
Excavation of soil/rock. |
Excavation of foundations
|
· Approximately volume 5500m3 - to be disposed of as public fill.
|
|
|
Municipal wastes – packing materials etc. |
Construction of Terminal Buildings.
|
· Approximately 250m3 to be used during construction.
|
|
|
Chemical wastes- paints, solvents fixatives. |
During the construction of the terminal buildings. |
· The chemical, wastes, paints solvents etc used is assumed to be 50L /month* for the entire site. |
|
Assumptions: -
1. Assume size of the platforms for the supporting towers and angle stations to be 15m x 15m;
2. Assume raft foundation instead of pile foundation to be used in supporting towers location to simulate the greater volume of excavated spoil generated during the construction;
3. Assume 1/3 of the excavated topsoil can be reused for vegetation re-provision in the Supporting Tower and Turning Angle stations;
4. Assume the emergency trail to be 1.5m wide;
5. Assume the footprint of the Tung Chung and Ngong Ping Terminals to be 50m x 25m;
6. Since Tung Chung Terminal is located in newly reclaimed land and no site clearance is therefore required;
7. Assume large bored pile foundation 2500mm diameter to be used in Tung Chung Terminal; and
8. Assume 600mm diameter pre-bored H piles to be used in Ngong Ping Terminal.
Note: Contractors will be required to minimise waste
Waste materials have the potential to cause adverse environmental impacts during generation, storage, transport and disposal. The principal adverse effects relate to dust, water quality, general health and safety and visual impacts. For each anticipated waste category, the potential environmental impacts are highlighted and appropriate mitigation measures/disposal options recommended below. These recommendations form the basis of the Waste Management Plan (WMP) and part of the monitoring and audit programme.
Waste management procedures should be implemented to minimise potential impacts to the environment. This may be achieved by consideration and application of the following protocols:
· avoid and/or minimise waste generation wherever practical by changing its quality or site procedures (e.g. convert excavated soil to topsoil by mixing with compost, allow excavated material for backfilling in other locations simultaneously);
· maximise the opportunity for reusing/recycling/recovering materials and thereby negate/minimise the disposal requirements (e.g. by waste segregation according to type, separation of recyclable materials such as metal, maximise reuse of timber formwork wherever possible, utilisation of excavated material for filling or landscaping); and
· ensure that all treatment and disposal options are comply with best practice and all relevant guidelines and legislation.
The following specific measures should therefore be adopted during the detailed design and construction stages of the project to minimise waste generation:
· Evaluate the opportunities for maximising the re-use of excavated materials for example, reusing all materials excavated for the tower bases as for the emergency rescue trail; and
· Allocate area within the construction site for the termini for sorting and segregation of materials.
· Segregate waste materials according to types to facilitate re-use and recycling;
· Separate inert construction and demolition materials for dumping into public filling area or landfill site;
· Segregate different materials at source as far as practical;
· Co-ordinate material deliveries to minimise storage times on site to avoid damage and producing waste material; and
· Provide training to site staff in waste minimisation practices as part of the environmental management systems training (as part of the Code of Practice).
A comprehensive site record should be maintained throughout the construction period for easy tracking of details on the quantities of materials; a) generated on site; b) reused on site; and c) disposed off site, together with disposal routes/locations. No burning of wastes materials on-site is allowed and no storage of materials/wastes will be permitted in the Country Park or Water Gathering Grounds.
Although this Project does not have to follow WBTC’s reference should be made to the WBTC No. 21/2002 “Trip-ticket System for Disposal of Construction and Demolition Material”, WBTC No. 25/99 “Incorporation of Information on Construction and Demolition Material Management” for guidance. The separation of inert C&D material (suitable for public filling) from C&D materials (considered unsuitable for use as public fill) is required to minimise the volumes requiring landfill disposal as far as practical.
WBTC No. 21/2002 refers to the implementation of a trip ticket system for the proper disposal of C&D material to either public filling areas or landfills. WBTC No. 25/99 refers to the management of construction and demolition material (C&DM), i.e. inert material suitable for use as public fill or in earth filling projects. Full reference should be made to the relevant WBTC for further details although the MTRC will develop that own procedures suitable for the Cable Car Project.
All excavated materials other than for re-use should be transported off site as soon as possible to minimise the potential adverse environmental impacts. Transportation of excavated material off site should be handled in a proper manner to minimise the release of fugitive dust (especially during hot and dry weather). Mitigation measures related to dust generated due to handling of excavated materials have been addressed in detail within Section 3 (Air Quality).
The following measures should be implemented to mitigate against the likely adverse impacts to the environment:
· excavated material and sites should be covered to prevent washout and erosion during heavy rainfall;
· adopt dust suppression techniques (such as dampening with fine water spray and covering with tarpaulin);
· avoid excessive use of water spraying to prevent generation of runoff contaminated with elevated levels of suspended solids;
· provide silt traps in the surface drainage system in the stockpile area;
· fence up the designated areas for stockpiling to separate sensitive habitats, and prevent stockpiling in inappropriate locations; and
· designate appropriate disposal routes.
A reduction in the total volume of excavated materials requiring disposal off-site can be achieved by optimising the re-use of suitable material on-site.
For the surplus excavated material and inert construction and demolition materials which require disposal at public filling areas, two possible locations have been identified. These are the public filling area at Tung Chung Development Phase 3A and the public fill stockpiling area at Mui Wo. Both were identified by the Secretary, Public Filling Committee (PFC) as possible locations available for dumping in accordance with the construction works programme.
Cleared vegetation derived from the site clearance should be segregated from any soil materials where practical and sent to a suitable disposal site such as the WENT Landfill. WENT Landfill will only accept a maximum of 30% by weight of inert construction waste. It is therefore important that soil / vegetation are kept segregated. Moreover, the opportunity for re-using the excavated topsoil for landscaping proposed either on-site, or for other landscaping projects, should be identified by the contractor prior to landfill disposal.
The excessive generation of inert construction and demolition material increases disposal costs and may take up valuable landfill space. With the implementation of good site management and careful planning, the over-ordering of materials and generation of inert construction and demolition material should be minimised. In accordance with WBTC No. 19/2001 (Metallic Site Hoardings and Signboards), re-useable metal hoarding and signboards should also be utilised on site to reduce the volumes of inert construction and demolition material (wood) generated.
Where possible, inert construction and demolition materials such as wood and metal should be separated out from other materials for recycling. All recyclable material should be clearly segregated and stored in appropriate skips/containers or stockpiled. Segregation of material will aid in the potential for re-use of material and in final disposal, if necessary. Material recycling or re-use reduces both the need for new construction materials and subsequent collection, transportation and disposal costs. Only when materials cannot be reused should they be disposed of to a public filling area or, as a last resort, landfilled. All construction and demolition material disposed at public filling sites must comply with the public dumping licensing requirements (e.g. the material should be inert and contain <5% by volume of timber). As far as possible, materials should be sorted to minimise the requirement for off site disposal.
It will be the Contractor's responsibility to ensure that inert construction and demolition material is collected by approved licensed waste collectors and that appropriate measures are taken to minimise adverse impacts such as dust generation. The Contractor must also ensure that all necessary disposal permits are obtained.
Bentonite slurries should be reused as far as possible and final residues disposed of in accordance with the Practice Note For Professional Persons ProPECC PN 1/94. Slurries may either be disposed of at the marine disposal grounds (subject to obtaining a licence from EPD) or to the public drainage system following treatment to satisfy relevant effluent discharge standards (as set out in the WPCO Technical Memorandum on Effluent Standards).
Chemical waste, as defined in the Waste Disposal (Chemical Waste) (General) Regulation, will require appropriate and approved disposal scheme to eliminate the potential hazards as a result of inappropriate handling of these materials. The potential hazards include:
· effects on human health (i.e. dermal and toxic effects with respect to site workers);
· phytotoxic effects to vegetation;
· contamination of the soil, groundwaters and surface water following spillage;
· risk of fire or explosions; and
· discharge of chemical wastes to sewer and potential disruption of the sewage treatment works.
Chemical wastes should be stored in a locked, fully bunded area which is impermeable to both water and the waste being stored. The waste storage area should also be covered to prevent rainfall from accumulating within the bunded areas. The bunded area must have a volume of either 110% of the largest container or 20% by volume of the chemical waste stored in that area. Appropriate spill absorption material should be stored near the storage area in order to clean up any minor spill events. The risks associated with chemical waste storage and handling can be further minimised by :
· designate an appropriate, well ventilated storage area;
· minimise waste production and recycling/reprocessing for certain waste liquids where appropriate (e.g. oils, solvents);
· careful handling of waste fuel and oil residues;
· use of appropriate and labelled (Chinese and English) storage containers;
· locate storage of wastes area away from sensitive receivers (e.g. drains, residential properties and water bodies); and
· provide education to workers to enhance their knowledge on site cleanliness and appropriate waste management procedures.
An appropriate disposal facility is the Chemical Waste Treatment Centre (CWTC) at Tsing Yi. If chemical wastes are to be generated, the contractor will need to register with EPD as a chemical waste producer and observe the requirements for chemical waste storage, labelling, transportation and disposal. The contractor will also need to consider the guidance in "A Guide to Chemical Waste Control Scheme: A Guide to the Registration of Chemical Waste Producers" and the "Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes". All chemical wastes should be collected from site by a licensed chemical waste collector.
Material that is not acceptable at the CWTC (such as spent batteries) should be sent to a co-disposal landfill such as the SENT Landfill.
If not appropriately managed, municipal wastes generated by site workers have a potential to cause impacts in terms of nuisance, insects and vermin. This may give rise to adverse environmental impacts for both site workers and site neighbours which could include:
· odour nuisance if putrescible material is not collected on a regularly basis;
· wind-blown material causing litter problems;
· propagate of vermin and pests if the waste storage area is not well maintained and cleaned regularly; and
· visually unpleasant.
A temporary refuse collection facilities should be set-up by the contractor and wastes should be stored in appropriate containers prior to collection and disposal. The temporary storage locations could be located at Ngong Ping, Nei Lak Shan Angle Station, near San Tau, Airport Angle Station, and Tung Chung as shown in Figure 6.1.
Domestic effluent generated by the workforce will be directed to foul sewer or chemical toilets if foul sewers are not available. For the operational phase domestic effluent generated at the terminals will be disposed of to the Ngong Ping Sewage Treatment Works or to foul sewer in Tung Chung.
A summary of the proposed mitigation measures and proposed disposal options are presented in Table 6.4 and form the Waste Management Plan for the proposed project works.
Table 6.4 Waste Management Plan
|
Waste Types |
Control Measures |
Disposal Method / Area |
|
General Requirements |
|
|
|
|
Detailed Design Stage · maximising the opportunity for re-use of excavated materials; · Reuse of excavated materials, topsoil, vegetation etc; · providing an area within the construction site to allow for sorting and segregation of materials.
|
- |
|
|
Construction Stage · minimisation of waste generation for disposal (via reduction/recycling/re-use); · segregating waste materials according to type to facilitate re-use and recycling; · separation of inert construction and demolition materials for either re-use on-site or use as public fill; · during demolition works, segregating materials at source as far as practical; · co-ordinate material deliveries to site in order to minimise storage times on site and the likelihood of causing damage; · training site staff in waste minimisation practices; · transport of wastes off site as soon as possible; · maintenance of comprehensive accurate waste records; · use of re-useable metal boarding / signboards; · no on-site burning will be permitted; · follow the practice set out in WBTC No. 21/2002 “Trip-ticket System for Disposal of construction and Demolition Material”. |
All areas. |
|
Cleared vegetation
|
· segregation of materials to facilitate disposal; · segregation of excavated topsoil from roots and re-use for the landscaping works to eliminate the need for off-site disposal.
|
Re-use |
|
Demolition waste |
· segregation of materials to facilitate disposal; · appropriate stockpile management; · follow the practice set out in WBTC No.5/98 “On site Sorting of Construction Waste on Demolition Sites”.
|
Public fill for inert wastes |
|
Excavated materials |
· segregation of materials to facilitate disposal / reuse; · appropriate stockpile management; · re-use of excavated material on or off site (where possible); · special handling and disposal procedures in the event that contaminated materials are excavated; · follow the practice set out in WBTC No. 21/2002 “Trip-ticket System for Disposal of construction and Demolition Material”. |
Re-use on site for suitable material. Disposal to public fill areas for unsuitable materials. |
|
Construction waste |
· segregation of materials to facilitate recycling/reuse (within designated area and in appropriate containers/stockpiles); · appropriate stockpile management; · planning and design considerations to reduce over ordering and waste generation; · recycling and re-use of materials where possible (e.g. metal, wood from boardings, formwork); · for material which cannot be re-used/recycled, collection should be carried out by an approved waste contractor for landfill disposal; · follow the practice set out in WBTC No.5/98 “On site Sorting of Construction Waste on Demolition Sites”.
|
Public fill for inert wastes.
Disposal to landfill for materials unsuitable for public filling |
|
Chemical waste |
· storage within locked, covered and bunded area at the terminal sites not in the Country Park; · the storage area should not be located adjacent to sensitive receivers e.g. drains; water courses; · minimise waste production and recycle oils/solvents where possible; · a spill response procedure should be in place and absorption material available for minor spillages; · use appropriate and labelled containers; · educate site workers on site cleanliness/waste management procedures; · if chemical wastes are to be generated, the contractor must register with EPD as a chemical waste producer; · collection by a licensed chemical waste collector.
|
Disposal offsite to an appropriate facility. |
|
Municipal waste |
· waste should be stored within a temporary refuse collection facility, in appropriate containers prior to collection and disposal; · regular, daily collections are required by an approved waste collector; and · provide sanitary facilities. |
Using a licensed waste disposal contractor. |
The proposed construction activities associated with the proposed works will generate waste materials. Some of which can be re-used in-situ (the preferred route) some which will need to be disposed of. These include:
Those which can be totally reused
· vegetation wastes from site clearance; and
· excavated materials for the emergency access trails.
Those requiring disposal
· construction and demolition materials;
· chemical waste; and
· municipal waste.
During the operational phase wastes will include wastewater from domestic effluent and maintenance oils/ lubricants etc. and general domestic wastes (lunch boxes paper etc.) measures given above provide appropriate measures to reduce waste arisings and to control wastes to acceptable levels.
The following sites were identified as possible locations for disposal of excavated materials, construction and demolition waste & materials, chemical waste in conjunction with the construction programme of the proposed works:
· the public filling area at Tung Chung Development Phase 3A;
· the public fill stockpiling area at Mui Wo;
· the landfill site WENT in West New Territories;
· Chemical Waste Treatment Centre (CWTC) at Tsing Yi; and
· material that is not acceptable at the CWTC (such as spent batteries) can be sent to a co-disposal landfill such as the SENT Landfill.