7                    waste management




7.1              Waste management would be the contractor’s responsibility to ensure that all wastes produced during the construction works for the extension of Siu Ho Wan WTW are handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements. 


7.2              Waste materials generated during construction activities, such as construction and demolition (C&D) materials and general refuse, are recommended to be audited at regular intervals (at least quarterly) to ensure that proper storage, transportation and disposal practices are being implemented.  This monitoring of waste management practices would ensure that these solid wastes generated during construction are not disposed of into the nearby streams or drainage channel.  The audits shall also check that any chemical wastes generated during maintenance of construction equipment and vehicles are not stored within the sites of the Siu Ho Wan WTW, , and the Pui O Raw Water Pumping Stations and Pui O No.2 Raw Water Pumping Station.  The Contractor would be responsible for the implementation of any mitigation measures to minimise waste or redress problems arising from the waste materials.

Waste Control and Mitigation Measures


7.3              Mitigation measures for waste management for both the designated project and non-designated project elements of the Project are summarised below.  These mitigation measures include measures specific to the proposed mainlaying works at Pui O and the Pui O pumping stations. With the appropriate handling, storage and removal of waste arisings during the construction works as defined below, the potential to cause adverse environmental impacts would be minimised.  The implementation schedule of the recommended mitigation measures for the designated project of Siu Ho Wan WTW Extension is presented in Appendix A.  During the site inspections, the ET shall pay special attention to the issues relating to waste management and check whether the Contractor has implemented the recommended good site practices and other mitigation measures.


Good Site Practices


7.4              It is expected that adverse impacts from waste management would not arise, provided that good site practices are strictly followed.  Recommendations for good site practices during construction activities include:

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

·      training of site personnel in proper waste management and chemical waste handling procedures;

·      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;

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

·      a Waste Management Plan should be prepared and submitted to the Engineer for approval.  One may make reference to ETWB TCW No.15/2003 for details; and

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


7.5              In order to monitor the disposal of C&D material at public filling areas and to control fly tipping, a trip-ticket system should be included as one of the contractual requirements to be implemented by an Environmental Team undertaking the Environmental Monitoring and Audit work.  One may make reference to WBTC No. 21/2002 for details.


Waste Reduction Measures


7.6              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;

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

·      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.


7.7              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. 


Construction and Demolition Material

7.8              In order to minimise the impact resulting from collection and transportation of C&D material for off-site disposal, the excavated soft spoil from open trench excavation at Pui O should be reused on-site as backfill material as far as practicable.  Suitable areas should be designated within the works site boundaries for temporary stockpiling of C&D material.  Within stockpile areas, the following measures should be taken to control potential environmental impacts or nuisance:


·      covering material during heavy rainfall;

·      locating stockpiles to minimise potential visual impacts; and

·      minimizing land intake of stockpile areas as far as possible.


7.9              When disposing C&D material at a public filling area, 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 Filling Supervisor. 


Chemical Wastes


7.10          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.  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. No chemical waste should be allowed to be stored within the site of the waterworks installations including the Siu Ho Wan WTW, and the , Pui O Raw Water Pumping Station and Pui O No.2 Raw Water Pumping Stations.  All chemical wastes should be removed from the waterworks installations at the first instance.

General Refuse


7.11          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.