6a.1.1.1 This section identifies the types of waste that are likely to be generated during construction and operation phases of the Project, and evaluates the potential environmental impacts that may result from these wastes. Mitigation measures and good site practices, including waste handling, storage and disposal, are recommended with reference to the applicable waste legislation and guidelines.
6a.2 Environmental Legislation, Policies, Plans, Standards and Criteria
6a.2.1.1 The criteria and guidelines for assessing waste management implications are outlined in Annex 7 and Annex 15 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), respectively.
6a.2.1.2
The following legislations also
cover the handling, treatment and disposal of waste in
· Waste Disposal Ordinance (Cap. 354) and subsidiary Regulations;
· Public Health and Municipal Services Ordinance (Cap. 132);
· Land (Miscellaneous Provisions) Ordinance (Cap. 28);
· Waste Disposal (Chemical Waste) (General) Regulation; and
· Waste Disposal (Charges for Disposal of Construction Waste) Regulation.
6a.2.2 Waste Disposal Ordinance (Cap. 354)
6a.2.2.1 The Waste Disposal Ordinance (WDO) prohibits any unauthorized disposal of waste. Construction waste, defined under Cap. 354N of the WDO refers to a substance, matter or thing which is generated from construction works. It includes all abandoned materials, whether processed or stockpiled or not, before being abandoned, but does not include sludge, screenings or matter removed or generated from desludging, desilting or dredging works. Under WDO, waste can be disposed of only at designated waste disposal facilities licensed by the Environmental Protection Department (EPD).
6a.2.3 Public Health and Municipal Services Ordinance (Cap. 132)
6a.2.3.1 The Public Cleansing and Prevention of Nuisances Regulation provides control on illegal tipping of waste on unauthorized (unlicensed) sites.
6a.2.4 Land (Miscellaneous Provisions) Ordinance (Cap 28)
6a.2.4.1 The inert portion of Construction and Demolition (C&D) materials (including rocks, soil, broken concrete, building debris, etc.) may be taken to public fill reception facilities. Public fill reception facilities (PFRFs) usually form part of land reclamation schemes and are operated by the Civil Engineering and Development Department (CEDD) and others. The Land (Miscellaneous Provisions) Ordinance requires that individuals or companies who deliver public fill to the public fill reception facilities to obtain Dumping Licences. The licences are issued by CEDD under delegated authority from the Director of Lands.
6a.2.4.2 Individual licences and windscreen stickers are issued for each vehicle involved. Under the licence conditions, public fill reception facilities will only accept soil, sand, rubble, brick, tile, rock, boulder, concrete, asphalt, masonry or used bentonite. In addition, in accordance with paragraph 11 of the Environment, Transport and Works Bureau (ETWB) Technical Circular (Works) (TC(W)) No. 31/2004, Public Fill Committee will advise on the acceptance criteria. The material will, however, be free from marine mud, household refuse, plastic, metal, industrial and chemical wastes, animal and vegetable matter and any other materials considered unsuitable by the public fill reception facility supervisor.
6a.2.5 Environmental Guidelines
6a.2.5.1 Other guidelines which detail how the Contractor should comply with are as follow:
·
A Guide to the Registration of
Chemical Waste Producers, Environmental Protection Department,
·
A Guide to the Chemical Waste
Control Scheme, Environmental Protection Department,
·
Code of Practice on Package,
Labelling and Storage of Chemical Wastes (1992), Environmental Protection
Department,
· Works Branch Technical Circular (WBTC) No. 2/93, Public Dumps;
· WBTC No. 2/93B, Public Filling Facilities;
· WBTC No.16/96, Wet Soil in Public Dumps;
· WBTC Nos. 4/98 and 4/98A, Use of Public Fill in Reclamation and Earth Filling Projects;
· WBTC Nos. 25/99, 25/99A and 25/99C, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers;
· WBTC No. 12/2000, Fill Management;
· WBTC No. 11/2002, Control of Site Crusher;
· WBTC No. 12/2002, Specification Facilitating the Use of Recycled Aggregates;
· ETWB TC(W) No. 33/2002, Management of Construction/Demolition Materials including Rocks;
· ETWB TC(W) No. 31/2004, Trip-ticket System for Disposal of Construction and Demolition Materials; and
· ETWB TC(W) No. 19/2005, Environmental Management on Construction Sites.
6a.3 Assessment Approach and Methodology
6a.3.1.1 Criteria for assessing waste management implications are outlined in Annex 7 of EIAO-TM. Whereas methods for assessing potential waste management impacts during construction and operation phases of the Project would be examined in accordance with Annex 15 of EIAO-TM, which includes the following:
· Estimation of types and quantities of the wastes generated;
· Assessment of potential impacts from the management of waste with respect to potential hazards, air and odour emissions, noise, wastewater discharge and public transport; and
· Impacts on the capacity of waste collection, transfer and disposal facilities.
6a.3.1.2 Opportunities for waste reduction have been assessed based upon the following:
· Avoidance and minimization of waste generation throughout design, construction and operation stage;
· Segregation of waste materials would be promoted and considered as the best management practices;
· Reuse and recycling on site or on other projects; and
· Material diversion to public fills as far as possible.
6a.4 Identification and Evaluation of Environmental Impacts
6a.4.1.1 The construction activities to be carried out for the proposed Project would generate a variety of wastes that can be divided into distinct categories based on their composition and ultimate method of disposal. The identified waste types include:
· Construction and demolition (C&D) materials;
· General refuse; and
· Chemical waste.
6a.4.1.2 The nature of each type of waste arising is described below, together with an evaluation of the potential environmental impacts associated with the waste.
Construction and Demolition Materials
6a.4.1.3 Construction and demolition (C&D) materials would be generated from site formation, foundation works for buildings and facilities, foundation piling and construction of the civil structures and access road. The estimated volume of C&D materials to be generated is 29,903m3. A breakdown of the estimated volumes of C&D materials and PFA generated from the construction of the Project is given in Table 6a.1.
Table 6a.1 Summary of C&D Materials Volumes
|
Type of C&D Material |
Material
generated (m3) |
Inert
C&D material to be reused on site (m3) |
Non-inert
C&D material to be collected for recycling (m3) |
Non-inert
C&D material to be disposed of off-site (m3) |
|
|
Inert Material |
Pulverised Fuel Ash
(PFA) |
21,415 |
21,415 |
0 |
0 |
|
Non-inert material |
Top soil &
vegetation |
4,387 |
0 |
0 |
4,387 |
|
Other(1) |
4,101 |
0 |
820 |
3,281 |
|
|
Total |
29,903 |
21,415 |
820 |
7,668 |
|
Note: (1) Other waste includes paper/cardboard packaging,
timber, metallic waste, etc.
6a.4.1.4 The C&D materials should be re-used on-site for filling works as far as possible to minimize the net amount of C&D materials generated from the Project. Filling works would include site formation, backfilling and access road construction. To avoid offsite disposal, the excavated PFA would be totally reused as filling material within the IWMF site area at the middle part of the ash lagoon. The volume of the C&D materials that cannot be reused and require disposal off-site is estimated to be approximately 7,688 m3.
6a.4.1.5 The amount of C&D materials and PFA expected to be generated shall be quantified in the site Waste Management Plan to be prepared by the Contractor. Since the construction activities would be located near the coast, improper management of C&D materials may introduce debris and pollutants to the water bodies, and mitigation measures, including adoption of good site practices, would be required for control of impacts. With proper implementation of good construction site practice and the mitigation measures recommended in Sections 3, 4 and 5, the handling and transportation of C&D materials to the disposal sites will not cause adverse dust, noise or water quality impacts.
Chemical Waste
6a.4.1.6
The maintenance and servicing
of construction plant and equipment may possibly generate some chemical wastes,
for instance, cleaning fluids, solvents, lubrication oil and fuel. Maintenance
of vehicles may also involve the use of a variety of chemicals, oil and lubricants.
It is difficult to quantify the amount of chemical waste that will arise from
the construction activities since it will be dependent on the Contractor’s
on-site maintenance requirements and the amount of plant utilised. However, it
is anticipated that the quantity of chemical waste, such as lubricating oil and
solvent produced from plant maintenance, would be small and in the order of a
few cubic metres per month. The amount of chemical waste expected to be
generated shall be quantified in the site Waste Management Plan to be prepared
by the Contractor.
6a.4.1.7 Chemical wastes generated during the construction phase may pose environmental, health and safety hazards if not stored and disposed of in an appropriate manner as stipulated in the Waste Disposal (Chemical Waste) (General) Regulations. The potential hazards include:
· Toxic effects to workers;
· Adverse impacts on water quality from spills; and
· Fire hazards.
6a.4.1.8 Materials classified as chemical wastes will be required for special handling and storage arrangements before removal for appropriate treatment such as the Chemical Waste Treatment Facility at Tsing Yi. Wherever possible, opportunities should be taken to reuse and recycle materials. Mitigation and control requirements for chemical wastes are detailed in Section 6a.5.1.8. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected to result.
General Refuse
6a.4.1.9 Throughout construction, the workforce would generate refuse comprising food scraps, waste paper, empty containers, etc. Release of general refuse into coastal waters should not be permitted, as introduction of these wastes is likely to have detrimental effects on water quality in the area. Rapid and effective collection of site wastes would be required to prevent waste materials being blown around by wind or flushed into the coastal waters or stream. The work sites may also attract pests and vermin and create odour nuisance if the waste storage area is not well maintained and cleaned regularly. Disposal of refuse at sites other than approved waste transfer or disposal facilities can also result in similar impacts. With the implementation of good waste management practices at the site, adverse environmental impacts would not be expected to arise from the storage, handling and transportation of workforce wastes. The maximum number of construction workers to be employed is estimated to be about 400 workers. Based on a generation rate of 0.65 kg per worker per day, the maximum daily arising of general refuse during the construction period would be approximately 260 kg.
6a.4.1.10 Potential environmental impacts will be insignificant provided that the mitigation measures and appropriate site practices suggested in Section 6a.5.1.9 and Table 6a.4 are implemented.
6a.4.2.1 As discussed in Section 2, the IWMF would comprise (a) an advanced thermal incineration plant of about 2,800 tpd capacity and (b) a demonstration-scale mechanical treatment (MT) plant of about 200tpd or less for mixed MSW. The wastes to be generated from the thermal incineration plant are discussed below:
Incineration By-products
6a.4.2.2 The main waste type to be generated during the operation of the thermal incineration plant would be bottom ash, fly ash and air pollution control (APC) residues. For treating 3,000 tpd of mixed MSW, it is estimated that approximately 660 tpd of bottom ash and 120 tpd of fly ash and APC residues would be generated from the thermal incineration plant.
6a.4.2.3 The bottom ash is considered to be inert provided that the combustion systems in the incinerator are designed and operated correctly, and would be disposed of at landfill. Fly ash and APC residues from the flue gas stream can also be disposed of at landfill after proper treatment. The pollution load in fly ash and APC residues would likely be higher and more readily leachable than that in bottom ash. Cement solidification or chemical stabilization would be adopted to pre-treat the fly ash and APC residue to ensure that they would conform to the proposed Incineration Residue Pollution Control Limits shown in Table 6a.2 and leachability criteria before disposal.
Table
6a.2 Incineration
Residue Pollution Control Limits
|
Pollutant Parameter |
Pollution Control Limit |
|
Each Skip Load Prior to Transportation to
Disposal Site |
|
|
Residue Itself: Bottom Ash and Fly Ash: |
|
|
·
Total organic
carbons (a) |
3% by wt (d) |
|
·
Dioxins/Furans (b) |
1 ppb (or 1 μg kg-1) |
|
|
|
|
Leachate Derived from the Residue: |
|
|
pH |
>8 |
|
Heavy Metals (c) |
|
|
· Cd |
10 ppm (or mg kg-1) |
|
· Cr |
50 ppm (or mg kg-1) |
|
· Cu |
250 ppm (or mg kg-1) |
|
· Ni |
250 ppm (or mg kg-1) |
|
· Pb |
50 ppm (or mg kg-1) |
|
· Zn |
250 ppm (or mg kg-1) |
|
· Hg |
1 ppm (or mg kg-1) |
|
· Sn |
250 ppm (or mg kg-1) |
|
· Ag |
50 ppm (or mg kg-1) |
|
· Sb |
150 ppm (or mg kg-1) |
|
· As |
50 ppm (or mg kg-1) |
|
· Be |
10 ppm (or mg kg-1) |
|
· Tl |
50 ppm (or mg kg-1) |
|
· V |
250 ppm (or mg kg-1) |
|
· Se |
1 ppm (or mg kg-1) |
|
· Ba |
1,000ppm (or mg kg-1) |
Notes:
(a) Checking of carbon burnout of the ash
is necessary to ensure adequate sterility
(b) I-TEQ (International Toxic Equivalents)
(c) Toxicity Characteristic Leaching
Procedure (TCLP) limits for landfill disposal
(d) The EU Directive on Incineration of Waste requires
a TOC of 3% by wt.
6a.4.2.4
The incineration ash
generated should not be considered as chemical wastes under the Waste Disposal
(Chemical Waste) (General) Regulation if the Toxicity Characteristic Leaching
Procedure (TCLP) results of the ash comply with the Incineration Residue Pollution
Control Limits. In case that the Incineration Residue Pollution Control Limits
are not conformed, pre-treatment to the ashes and residues, such as cement
solidification or chemical stabilization, will be required to ensure compliance
of the proposed Incineration Residue Pollution Control Limits.
6a.4.2.5
To confirm that the bottom
ash, and the treated fly ash and APC residues of the IWMF would not contain
elevated levels of heavy metals and as a precautionary measure, it is proposed
that TCLP tests be carried out for each batch of bottom ash and treated fly ash
and APC residues to be disposed of at WENT Landfill at the initial stage of the
IWMF operation (i.e. for a period of 6 months). If the test results confirm
that heavy metals or pH are not of concern, the TCLP test can be deleted or
reduced to half-yearly intervals.
MT By-products
6a.4.2.6 For MT plant, the materials that are sorted out by the mechanical treatment but considered inappropriate to be recycled (e.g. badly-contaminated paper and plastics) would be treated as refuse.
6a.4.2.7 The estimated amount of refuse would be about 185 tpd. Most of the refuse will be diverted to the incinerators of the IWMF for combustion. Only a small amount of undersize, non-combustible inert refuse (about 23 tpd), which contains glass, sand, etc., will be disposed of at the WENT Landfill.
6a.4.2.8 The estimated quantities of waste products generated from the operation of the IWMF are indicated in Table 6a.3 below. The incineration and MT by-products produced from the IWMF will be hauled by the IWMF landfill tractors to the WENT landfill for disposal. The estimated round trip of tractors is about 50 vehicles per day.
Table 6a.3 Summary of Waste Generation from Operation of the IWMF
|
Waste Product |
Quantity |
Disposal Route |
|
Incineration
by-products |
||
|
Bottom Ash |
660 tpd |
To be complied with
proposed Incineration Residue Pollution Control Limits prior to disposal to WENT landfill |
|
Fly ash and APC Residue |
120 tpd (240 tpd after cementation) |
Pre-treatment would be applied
(e.g. cement solidification) for compliance with proposed Incineration
Residue Pollution Control Limits prior to disposal to WENT
landfill. |
|
MT by-products |
||
|
Refuse from MT |
162 tpd |
Refuse (e.g. badly contaminated textiles, wood and residual paper, plastics etc.) to be diverted to the incinerators of the IWMF for combustion. |
|
23 tpd |
Undersized,
non-combustible inert refuse (e.g. glass,
sand, residual metals etc.) to be disposed at WENT landfill. |
|
6a.5 Mitigation of Adverse Environmental Impacts
6a.5.1.1 This section recommends the mitigation measures needed to avoid or minimize potential adverse environmental impacts associated with the handling, collection and disposal of waste arising from the construction and operation of the IWMF.
Good Site Practices
6a.5.1.2 Adverse environmental impacts in relation to waste management are not expected, provided that good site practices are strictly followed. Recommendations for good site practices during the construction activities would include:
· Obtain relevant waste disposal permits from appropriate authorities, in accordance with the Waste Disposal Ordinance (Cap. 354) and subsidiary Regulations and the Land (Miscellaneous Provisions) Ordinance (Cap. 28);
· Provide staff training for proper waste management and chemical handling procedures;
· Provide sufficient waste disposal points and regular waste collection;
· Provide appropriate measures to minimise windblown litter and dust during transportation of waste by either covering trucks or by transporting wastes in enclosed containers; and
· Carry out regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors;
· Separate chemical wastes for special handling and disposed of to licensed facility for treatment; and
· Employ licensed waste collector to collect waste.
Waste Reduction Measures
6a.5.1.3 Good management and control can prevent the generation of a significant amount of waste. Waste reduction is best achieved at the planning and design stage, as well as by ensuring the implementation of good site practices. Recommendations to achieve waste reduction include:
· Design foundation works that could minimise the amount of excavated material to be generated.
· Provide training to workers on the importance of site cleanliness and appropriate waste management procedures, including waste reduction, reuse and recycling;
· Sort out demolition debris and excavated materials from demolition works to recover reuseable/recyclable portions (i.e. soil, broken concrete, metal etc.);
· Segregate and store different types of waste in different containers, skips or stockpiles to enhance reuse or recycling of materials and their proper disposal;
· Encourage the collection of aluminium cans by providing separate labelled bins to enable this waste to be segregated from other general refuse generated by the work force;
· Proper storage and site practices to minimise the potential for damage or contamination of construction materials; and
· Plan and stock construction materials carefully to minimise amount of waste to be generated and to avoid unnecessary generation of waste.
6a.5.1.4 In addition to the above measures, specific mitigation measures are recommended below for the identified waste so as to minimise environmental impacts during handling, transportation and disposal of the waste.
Construction and Demolition Materials
6a.5.1.5 In order to minimise the impact resulting from collection and transportation of C&D materials for off-site disposal, the excavated material arising from site formation and foundation works should be reused on-site as backfilling material and for landscaping works as far as practicable. Other mitigation requirements are listed below:
· A Waste Management Plan (WMP), which becomes part of the Environmental Management Plan (EMP), should be prepared in accordance with ETWB TCW No.19/2005;
· A recording system for the amount of wastes generated, recycled and disposed (including the disposal sites) should be adopted for easy tracking; and
· In order to monitor the disposal of C&D materials at public filling facilities and landfills and to control fly-tipping, a trip-ticket system should be adopted (refer to ETWB TCW No. 31/2004).
6a.5.1.6 The Contactor should prepare and implement an EMP in accordance with ETWB TCW No.19/2005, which describes the arrangements for avoidance, reuse, recovery, recycling, storage, collection, treatment and disposal of different categories of waste to be generated from construction activities. Such a management plan should incorporate site specific factors, such as the designation of areas for segregation and temporary storage of reusable and recyclable materials. The EMP should be submitted to the Engineer for approval. The Contractor should implement waste management practices in the EMP throughout the construction stage of the Project. The EMP should be reviewed regularly and updated by the Contractor, preferably on a monthly basis.
6a.5.1.7 All surplus C&D materials arising from or in connection with construction works should become the property of the Contractor when it is removed unless otherwise stated. The Contractor would be responsible for devising a system to work for on-site sorting of C&D materials and promptly removing all sorted and process materials arising from the construction activities to minimize temporary stockpiling on-site. The system should be included in the EMP identifying the source of generation, estimated quantity, arrangement for on-site sorting, collection, temporary storage areas and frequency of collection by recycling Contractors or frequency of removal off-site.
Chemical Wastes
General Refuse
6a.5.1.10 Table 6a.4 provides a summary of the various waste types likely to be generated during the construction activities for the IWMF, together with the recommended handling and disposal methods. The detailed disposal transportation routings and trip frequency would be subject to the actual construction programme.
Table 6a.4 Summary of Waste Handling Procedures and Disposal Outlets during
Construction Phase
|
Waste Type |
Generated from works item |
Total Amount Generated |
Amount to be disposed of |
Handling Process |
Recommended Disposal
Outlets / |
|
C&D Materials & PFA |
Site formation; Foundation Works; Construction of civil structures & access road |
29,903 m3 |
7,668 m3 |
Segregate inert C&D materials i.e. public fill to avoid contamination from other
waste arisings |
Inert material (i.e. excavated PFA) to be reused on-site for filling
works including site formation, backfilling and road widening (21,415 m3) Recyclable non-inert material such as metallic waste and paper/cardboard
packaging to be collected for recycling (820 m3) C&D materials cannot be reused or recycled to be disposed to
public fill reception facilities (PFRFs) by land transport upon approval from
CEDD. |
|
Chemical Waste |
Cleansing fluids, solvent, lubrication oil and fuel from construction plants
and equipment |
Few cubic meters/month (preliminary estimate) |
Few cubic meters/month |
Collected for disposal by licensed collector; Stored on-site within
suitably designed containers |
Disposed of to Chemical Waste Treatment Centre by land transport |
|
General Refuse |
Waste paper, empty container generated from workforce |
260 kg/ day |
260 kg/ day |
Provide on-site refuse collection points |
Disposed of to Refuse station for compaction and containerisation and then
to landfill by land transport |
Good Site Practices
6a.5.2.1 It is recommended that the following good operational practices should be adopted to minimise waste management impacts:
· Obtain the necessary waste disposal permits from the appropriate authorities, in accordance with the Waste Disposal Ordinance (Cap. 354) and Waste Disposal (Chemical Waste) (General) Regulation;
· Nomination of an approved person to be responsible for good site practice, arrangements for collection and effective disposal to an appropriate facility of all wastes generated at the site;
· Use of a waste haulier licensed to collect specific category of waste;
· A trip-ticket system should be included as one of the contractual requirements and implemented by the Environmental Team to monitor the disposal of solid wastes at landfills, and to control fly tipping. Reference should be made to ETWB TCW No. 31/2004.
· Training of site personnel in proper waste management and chemical waste handling procedures;
· Separation of chemical wastes for special handling and appropriate treatment at a licensed facility;
· Routine cleaning and maintenance programme for drainage systems, sumps and oil interceptors;
· Provision of sufficient waste disposal points and regular collection for disposal;
· Adoption of appropriate measures to minimize windblown litter and dust during transportation of waste, such as covering trucks or transporting wastes in enclosed containers; and
· Implementation of a recording system for the amount of wastes generated, recycled and disposed of (including the disposal sites).
Waste Reduction Measures
6a.5.2.2 Good management and control can prevent the generation of significant amounts of waste. It is recommended that the following good operational practices should be adopted to ensure waste reduction:
· Segregation and storage of different types of waste in different containers, skips or stockpiles to enhance reuse or recycling of materials and their proper disposal;
· Encourage collection of aluminium cans, plastic bottles and packaging material (e.g. carton boxes) and office paper by individual collectors. Separate labelled bins should be provided to help segregate this waste from other general refuse generated by the work force; and
· Any unused chemicals or those with remaining functional capacity should be reused as far as practicable.
Storage, Handling, Treatment, Collection and Disposal of Incineration By-Products
6a.5.2.3 The following measures are recommended for the storage, handling and collection of the incineration by-products:
· Ash should be stored in storage silos;
· Ash should be handled and conveyed in closed systems fully segregated from the ambient environment;
· Ash should be wetted with water to control fugitive dust, where necessary;
· All fly ash and APC residues should be treated, e.g. by cement solidification or chemical stabilization, for compliance with the proposed Incineration Residue Pollution Control Limits and leachability criteria prior to disposal;
· The ash should be transported in covered trucks or containers to the designated landfill site.
6a.5.2.4 The Contractor should provide EPD with chemical analysis results of the bottom ash, and treated fly ash and APC residues to confirm that the ash/residue can comply with the proposed Incineration Residue Pollution Control Limits before disposal.
6a.6 Contamination Prevention Measures
6a.6.1.1 The IWMF is proposed to be located at the TTAL site. Based on the available information, the lagoons were constructed in year 1987 and the lagoons have been used solely for ash disposal purpose since its formation. No other contaminating activities including storage and use of chemicals or fuels were practised on site. This is verified by review of historic aerial photos and no observable contamination was noticed in recent site walkover. Potential land contamination impact associated with the previous uses of the lagoon site is therefore not anticipated.
6a.6.1.2
With reference to Clause 3.4.4.3 of the EIA Study Brief, the following
tasks have been conducted
in accordance with the Guidance Manual
for Use of Risk based Remediation Goals
for
· Identify the possible sources of contamination associated with the operation of the Project; and
· Formulate appropriate operational practices, waste management strategies and precautionary measures for the prevention of contamination problems.
6a.6.2 Potential Sources of Contamination
6a.6.2.1 A variety of chemicals is expected to be used during the IWMF operation. Moreover, the IWMF operation would produce chemical wastes and incineration residues. Without proper management of the chemicals, chemical wastes and incineration residues, there is potential for land contamination due to uncontrolled spillages, or improper handling and disposal of these materials.
6a.6.2.2 The expected types and quantities of the materials involved in the IWMF operation with contamination potential are presented in Table 6a.5.
6a.6.2.3 A minimum amount of chemical wastes are expected to be generated. Chemical wastes will only arise if chemicals are over-ordered and cannot be consumed before the expiry of the chemicals.
Table 6a.5 Materials used in the IWMF Operation with Land Contamination Potential
|
Material |
Expected Annual Consumption
/ Production |
Estimated
Quantity to be Stored On-site |
|
Chemicals Consumption |
||
|
Slaked lime |
12,065 tonnes |
496 tonnes |
|
Ammonia water |
4,015 tonnes |
165 tonnes |
|
Activated carbon |
383 tonnes |
31 tonnes |
|
Kerosene |
283 m3 |
12 m3 |
|
Caustic soda |
206 tonnes |
8,466 kg |
|
Hydrochloric acid |
83 tonnes |
3,411 kg |
|
Sulfurous acid |
3,906 kg |
161 kg |
|
Production of Incineration By-products |
||
|
Bottom Ash |
240,900 tonnes |
1,980 m3 |
|
Fly ash & APC residues |
43,800 tonnes |
360 m3 |
6a.6.3 Approach to Prevent Land Contamination
Fuel Oil Spillage Prevention
6a.6.3.1 Precautionary measures to prevent fuel oil spillage are presented below.
(i) Fuel Oil Tank Construction and Test
Ÿ The fuel tank to be installed should be of specified durability.
Ÿ Double skin tanks are preferred.
Ÿ Underground fuel storage tank should be placed within a concrete pit.
Ÿ The concrete pit shall be accessible to allow regular tank integrity tests to be carried out at regular intervals.
Ÿ Tank integrity tests should be conducted by an independent qualified surveyor or structural engineer.
Ÿ Any potential problems identified in the test should be rectified as soon as possible.
(ii) Fuel Oil Pipeline Construction and Test
Ÿ Installation of aboveground fuel oil pipelines is preferable; if underground pipelines are unavoidable, concrete lined trenches should be constructed to contain the pipelines.
Ÿ Double skin pipelines are preferred.
Ÿ Distance between the fuel oil refuelling points and the fuel oil storage tank shall be minimized.
Ÿ Integrity tests for the pipelines should be conducted by an independent qualified surveyor or structural engineer at regular intervals.
Ÿ Any potential problems identified in the test should be rectified as soon as possible.
(iii) Fuel Oil Leakage Detection
Ÿ Installation of leak detection device at storage tank and pipelines.
Ÿ Installation and use of pressure gauges (e.g. at the two ends of a filling line) in fuel filling, which allows unexpected pressure drop or difference and sign of leakage to be detected.
(iv) Fuel Oil Storage Tank Refuelling
Ÿ Storage tank refuelling (from road tanker) should only be conducted by authorized staff of the oil company using the company’s standard procedures.
(v) Fuel Oil Spillage Response
o
Training
Training on oil spill response actions should be given to relevant staff. The training shall cover the followings:
- Tools & resources to combat oil spillage and fire, e.g. locations of oil spill handling equipment and fire fighting equipment;
- General methods to deal with oil spillage and fire incidents;
- Procedures for emergency drills in the event of oil spills and fire; and
- Regular drills shall be carried out.
o
Communication
Establish communication channel with the Fire Services Department (FSD) and EPD to report any oil spillage incident so that necessary assistance from relevant department can be quickly sought.
o
Response
Procedures
Any fuel oil spillage within the IWMF site should be immediately reported to the Plant Manager with necessary details including location, source, possible cause and extent of the spillage.
Plant Manager should immediately attend to the spillage and initiate any appropriate action to confine and clean up the spillage. The response procedures shall include the following:
- Identify and isolate the source of spillage as soon as possible.
- Contain the oil spillage and avoid infiltration into soil/ groundwater and discharge to storm water channels.
- Remove the oil spillage.
- Clean up the contaminated area.
- If the oil spillage occurs during storage tank refuelling, the refueling operation should immediately be stopped.
- Recovered contaminated fuel oil and the associated material to remove the spilled oil should be considered as chemical waste. The handling and disposal procedures for chemical wastes are discussed in the following paragraphs.
Chemicals and Chemical Wastes Handling & Spillage Prevention
(i) Chemicals and Chemical Wastes Handling & Storage
Ÿ Chemicals and chemical wastes should only be stored in suitable containers in purpose-built areas.
Ÿ
The storage of chemical wastes should comply with the requirements of the
Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes.
Ÿ
The storage areas for chemicals and chemical wastes shall have an impermeable
floor or surface. The impermeable floor/ surface shall possess the following
properties:
o
Not liable to chemically react with the materials and their containers
to be stored.
o
Able to withstand normal loading and physical damage caused by container
handling
o
The integrity and condition of the impermeable floor or surface should
be inspected at regular intervals to ensure that it is satisfactorily
maintained
Ÿ
For liquid chemicals and chemical wastes storage, the storage area
should be bunded to contain at least 110% of the storage capacity of the
largest containers or 20% of the total quantity of the chemicals/chemical
wastes stored, whichever is the greater.
Ÿ
Storage containers shall be checked at regular intervals for their
structural integrity and to ensure that the caps or fill points are tightly
closed.
Ÿ
Chemical handling shall be conducted by trained workers under supervision.
(ii) Chemicals and Chemical Wastes Spillage Response
o
Training
Training on spill response actions should be given to relevant staff. The training shall cover the followings:
- Tools & resources to handle spillage, e.g. locations of spill handling equipment;
- General methods to deal with spillage; and
- Procedures for emergency drills in the event of spills.
o
Communication
Establish communication channel with FSD and EPD to report the spillage incident so that necessary assistance from relevant department can be quickly sought.
o
Response
Procedures
Any spillage within the IWMF site should be reported to the Plant Manager.
Plant Manager shall attend to the spillage and initiate any appropriate actions needed to confine and clean up the spillage. The response procedures shall include the followings:
- Identify and isolate the source of spillage as soon as possible;
- Contain the spillage and avoid infiltration into soil/ groundwater and discharge to storm water channels (in case the spillage occurs at locations out of the designated storage areas);
- Remove the spillage; the removal method/ procedures documented in the Material Safety Data Sheet (MSDS) of the chemicals spilled should be observed;
- Clean up the contaminated area (in case the spillage occurs at locations out of the designated storage areas); and
- The waste arising from the cleanup operation should be considered as chemical wastes.
Preventive Measures for Incineration By-products Handling
6a.6.3.3 The recommended measures listed below can minimize the potential contamination to the surrounding environment due to the incineration by-products:
· Ash should be stored in storage silos;
· Ash should be handled and conveyed in closed systems fully segregated from the ambient environment;
· Ash should be wetted with water to control fugitive dust, where necessary;
· All fly ash and APC residues should be treated, e.g. by cement solidification or chemical stabilization, for compliance with the proposed Incineration Residue Pollution Control Limits and leachability criteria prior to disposal;
· The ash should be transported in covered trucks or containers to the designated landfill site.
Incident Record
6a.6.3.4 After any spillage, an incident report should be prepared by the Plant Manager. The incident report should contain details of the incident including the cause of the incident, the material spilled and estimated spillage amount, and also the response actions undertaken. The incident record should be kept carefully and able to be retrieved when necessary.
6a.6.3.5 The incident report should provide sufficient details for the evaluation of any environmental impacts due to the spillage and assessment of the effectiveness of measures taken.
6a.6.3.6
In case any spillage or accidents results in significant land
contamination, EPD should be informed immediately and the IWMF operator should
be responsible for the cleanup of the affected area. The responses procedures described in Section 6a.6.3.1 and Section 6a.6.3.2 above should be followed accordingly together with
the land contamination assessment and remediation guidelines stipulated in the Guidance Manual for Use of Risk-based
Remediation Goals for
6a.7 Evaluation of Residual Impacts
6a.7.1.1 With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste, no adverse residual impact is expected to arise during the construction of the proposed Project.
6a.7.1.2 For the operation phase of the Project, provided that the incineration by-products of the IWMF operation comply with the proposed Incineration Residue Pollution Control Limits as recommended in Table 6a.2 and leachability criteria of material prior to disposal at landfill, the residual impact arising from the disposal of the incineration by-products is considered to be minimal and thus acceptable. Besides, with the implementation of the contamination preventive measures, contamination problems during the operation phase of the Project are not expected.
6a.8 Environmental Monitoring and Audit
6a.8.1.1 It would be the Contractor’s responsibility to ensure that all wastes produced during the construction of the Project are handled, stored and disposed of in accordance with the recommended good waste management practices and EPD’s regulations and requirements. A Waste Management Plan (WMP) which would become part of the Environmental Management Plan (EMP) should be prepared in accordance with ETWB TCW No.19/2005 by the Contractor. The mitigation measures recommended in this section should form the basis of the WMP.
6a.8.1.2 Waste materials generated from construction activities, such as construction and demolition (C&D) materials and general refuse, are recommended to be audited at regular intervals (at least once per week as part of the regular site inspections described in EM&A Manual) to ensure that proper storage, transportation and disposal practices are being implemented. The Contractor would be responsible for the implementation of the mitigation measures to minimize waste or redress problems arising from the waste materials.
6a.8.1.3 Besides, during operation phase of the Project, it is recommended that the incineration by-products should be tested in accordance with the requirements of the proposed Incineration Residue Pollution Control Limits as recommended in Table 6a.2 above prior to disposal to landfill. A number of the land contamination preventive measures are also recommended for the operation of the Project.
6a.9.1.1 Waste types generated by the construction activities for the IWMF are likely to include C&D materials (from site formation, foundation works and construction of access road), general refuse from the workforce and chemical wastes from the maintenance of construction plant and equipment. Provided that the waste is handled, transported and disposed of using approved methods and that the recommended good site practices are strictly followed, adverse environmental impacts would not be expected during the construction phase.
6a.9.1.2 The end product from the incineration process would be bottom ash, fly ash and APC residues which would be disposed of at landfill after complied with the proposed incineration residue pollution control limits. Pre-treatment would be applied for fly ash and APC residues prior to disposal. A small amount of non-combustible inert refuse (e.g. glass, sand, residual metals etc.) sorted out in the MT process would be disposed of at landfill.
6a.9.1.3 The potential sources of contamination in the IWMF operation have been identified. Limited amount of chemicals or chemical wastes would be used/ produced in the IWMF operation. Good practices and response procedures for contamination prevention have been recommended. With proper implementation of the recommended practices and procedures, the potential for contamination due to the IWMF operation is expected to be minimal.