6.                  WASTE MANAGEMENT ImPLICATIONS

Introduction

6.1              This section identifies the types of wastes that are likely to be generated during the construction and operation phases of the proposed slip roads and evaluates the potential environmental impacts that may result from these waste arisings.  The main solid waste management implications are related to construction and demolition (C&D) material from the foundation works for the slip roads.  Mitigation measures and good site practice, including waste handling, storage and disposal are recommended with reference to the applicable waste legislation and guidelines.

6.2              The operation phase of the slip roads would generate wastes associated with roadside littering and road maintenance activities, and the amount would be expected to be minimal.  The potential environmental impacts arising from the handling and disposal of this small amount of waste are anticipated to be negligible and therefore have not been evaluated further in this report.

Environmental Legislation and Standards

6.3              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 Ordinance (EIAO-TM), respectively.

6.4              The following legislation relates to the handling, treatment and disposal of wastes in the Hong Kong SAR and will be used in assessing potential impacts:

·           Waste Disposal Ordinance (Cap. 354);

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

·           Land (Miscellaneous Provisions) Ordinance (Cap. 28);

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

6.5              The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes.  Construction waste is not directly defined in the WDO but is considered to fall within the category of “trade waste”.  Trade waste is defined as waste from any trade, manufacturer or business, or any waste building, or civil engineering materials, but does not include animal waste.  Under the WDO, wastes can be disposed of at sites licensed by the EPD.

6.6              The Public Cleansing and Prevention of Nuisance Regulation provides control on illegal tipping of wastes on unauthorised (unlicensed) sites.

Construction and Demolition (C&D) Materials

6.7              The current policy relating to the disposal of C&D material([1]) is documented in the Works Bureau Technical Circular No. 2/93B, ‘Public Filling Facilities’.  Construction and demolition materials that are wholly inert, namely public fill, should not be disposed of to landfill, but taken to public filling facilities which usually form part of reclamation schemes.  The Land (Miscellaneous Provisions) Ordinance requires that dumping licences are obtained by individual or companies who deliver public fill to public filling facilities.  The licences are issued by the Civil Engineering Department (CED) under delegated powers from the Director of Lands.

6.8              The Environment, Transport and Works Bureau (ETWB) Technical Circular (Works) No. 15/2003 sets out the policy and procedures requiring contractors to prepare and implement an enhanced Waste Management Plan to encourage on-site sorting of C&D materials and to minimize their generation during the course of construction. 

Chemical Waste

6.9              Under the regulation of WDO, the Chemical Waste (General) Regulation provides regulations for chemical waste control, and administers the possession, storage, collection, transport and disposal of chemical wastes.  The Environmental Protection Department (EPD) has also issued a ‘guideline’ document, the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), which details how the Contractor should comply with the regulations on chemical wastes.

Assessment Methodology and Criteria

6.10          The criteria for assessing waste management implications are outlined in Annex 7 of the EIAO-TM.  The methods for assessing potential waste management impacts during the construction and operation phases of the Project follow those presented in Annex 15 of the EIAO-TM and include the following:

·           estimation of the types and quantities of the wastes generated;

·           assessment of potential impacts from the management of solid waste with respect to potential hazards, air and odour emissions, noise and wastewater discharges; and

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

Identification and Evaluation of Environmental Impacts

6.11          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: 

·          C&D materials;

·          general refuse; and

·          chemical waste.

6.12          The nature of each type of waste arising is described in the following section, together with an evaluation of the potential environmental impacts associated with these waste arisings.

Construction and Demolition Materials

6.13          Construction and demolition (C&D) material would be generated from foundation works for the construction of the bored piles for the slip roads during the period June 2005 to May 2006 (Figure 2.8 refers).  The total volume of C&D material was estimated by the Project Engineer to be approximately 4,260 m3.   A breakdown of the estimated quantities of C&D material from the different works areas of the Project is given in Table 6.1 below.

 

Table 6.1         Summary of Estimated Quantities of C&D Material

Location

Public Fill (m3)

Public Fill (m3) (reusable)

Location to where the reusable material will be transported 

Slip Road A

57

350

To retaining walls at slip road A

Slip Road B

1,580

323

To retaining walls at slip road B

Slip Road F

301

1,304

To retaining walls at slip roads A & F

Bridge A

145

200

To retaining walls at slip road F

Total (m3)

2,083

2,177

 

 

6.14          The C&D material would be mostly sand and rock.  It was estimated that approximately 2,177m3 of the C&D material would be suitable for reuse on-site as fill material during the construction of the retaining walls, and approximately 2,083 m3 of C&D material comprising soil and silt/clay would require disposal off-site to the public filling facility designated by CED.   

General Refuse

6.15          Throughout construction, the workforce would generate general refuse comprising food scraps, waste paper, empty containers, etc.  Release of general refuse into the adjacent nullahs 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, flushed or leached into the aquatic environment, and odour nuisance.  The work sites may also attract pests and vermin 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.

6.16          With the implementation of the recommended waste management practices at the site, adverse environmental impacts would not arise from the storage, handling and transportation of refuse.

Chemical Waste

6.17          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.

6.18          Chemical wastes arising 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.

6.19          It is difficult to quantify the amount of chemical waste that will arise from the construction activities since it would be highly dependent on the Contractor’s on-site maintenance requirements and the number 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 hundred litres per month. The amount of chemical waste expected to be generated would be quantified in the site Waste Management Plan to be prepared by the Contractor.

6.20          Materials classified as chemical wastes would require special handling and storage arrangements before removal for appropriate treatment at 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 6.28.  Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected to result.

Mitigation Measures

Good Site Practices

6.21          It is not anticipated that adverse waste management related impacts would arise, provided that good site practices are strictly followed.  Recommendations for good site practices during the construction activities include:

·           nomination of an approved personnel, such as a site manager, to be responsible for the implementation of good site practices, arrangements for collection and effective disposal to an appropriate facility, of all wastes generated at the site;

·          training of site personnel in site cleanliness, appropriate waste management procedures, including chemical waste handling procedures, and concepts of waste reduction, reuse and recycling;

·           provision of sufficient waste disposal points and regular collection for disposal;

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

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

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

·           a recording system for the amount of wastes generated, recycled and disposed (including the disposal sites) should be proposed; and

·           a waste management plan (WMP) should be prepared in accordance with ETWB TC No. 15/2003 and submitted to the Engineer for approval. 

6.22          In order to monitor the disposal of C&D material at public filling facilities and to control fly tipping, the Trip-Ticket System in accordance with ETWB TC No. 21/2002 should be included as one of the contractual requirements and implemented by the Environmental Team undertaking the environmental monitoring and audit work.  Disposal of C&D material shall only be permitted at the public filling facility designated by CED.  C&D material shall not be permitted to be dumped to fish ponds or other illegal locations.

Waste Reduction Measures

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

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

·           to encourage collection of aluminium cans by individual collectors, separate labelled bins shall be provided to segregate this waste from other general refuse generated by the work force;

·           any unused chemicals or those with remaining functional capacity shall be recycled;

·           maximising the use of reusable steel formwork to reduce the amount of C&D material;

·           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 generated and avoid unnecessary generation of waste.

6.24          In addition to the above good site practices and waste reduction measures, specific mitigation measures are recommended below for the identified waste arisings to minimise environmental impacts during handling, transportation and disposal of these wastes. 

General Refuse

6.25          General refuse should be stored in enclosed bins or compaction units separate from C&D material.  A reputable waste collector should be employed by the contractor to remove general refuse from the site, separately from C&D material.  An enclosed and covered area is preferred to reduce the occurrence of 'wind blown' light material. 

Construction and Demolition Material

6.26          In order to minimise the impact resulting from collection and transportation of C&D material for off-site disposal, the material suitable for reuse shall be reused on-site as backfill material as far as possible. 

6.27          When disposing C&D material at a public filling facility, it shall be noted that the material shall only consist of soil, rock, concrete, brick, cement plaster/mortar, inert building debris, aggregates and asphalt.  The material shall be free from marine mud, household refuse, plastic, metals, industrial and chemical waste, animal and vegetable matter, and other material considered to be unsuitable by the public fill operators.

Chemical Wastes

6.28          If chemical wastes are produced at the construction site, the Contractor would be required to register with the EPD as a Chemical Waste Producer and to follow the guidelines stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes.   Good quality containers compatible with the chemical wastes should be used, and incompatible chemicals should be stored separately.  Appropriate labels should be securely attached on each chemical waste container indicating the corresponding chemical characteristics of the chemical waste, such as explosives, flammable, oxidizing, irritant, toxic, harmful, corrosive, etc.  The Contractor shall use a licensed collector to transport and dispose of the chemical wastes generated at the Chemical Waste Treatment Centre at Tsing Yi, or other licenced facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.

Evaluation of Residual Impact

6.29          With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste arisings, no residual impact was anticipated during the construction works for the proposed slip roads.

Environmental Audit

6.30          Waste management 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 good waste management practices and EPD’s regulations and requirements.

 

 



([1])    “C&D material” contains a mixture of inert and non-inert material.  The inert portion is the “public fill” and the non-inert portion is the “C&D waste”.