3                    water Qualityste management

 

Introduction

 

3.1               Water quality impact during operational phase will be minimized through implementation of the recommended design and practices as outlined in ProPECC PN5/93 recommended in Sections 3.18 to 3.26.  Water quality audit requirements will therefore cover the construction phase only.

 

 

3.2               Waste management would be It is the contractor’s responsibility to ensure that all wastewater or site runoffs produced during the construction works for the heliport expansion extension of Siu Ho Wan WTW aare handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements. 

 

3.1               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 marine watersstreams 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.

3.3               Implementation of regular site audits is recommended to ensure that the recommended mitigation measures are to be properly undertaken during construction phase of the Project. It can also provide an effective control of any malpractices and therefore achieve continual improvement of environmental performance on site.

 

3.4               Site audits shall include site inspections and compliance audits.

 

Site Inspections

 

3.5               Site inspections shall be carried out by the ET and shall be based on the mitigation measures for water pollution control recommended in Sections 3.10 to 3.157 below. In the event that the recommended mitigation measures are not fully or properly implemented, deficiency shall be recorded and reported to the site management. Suitable actions are to be carried out to:

·         Investigate the problems and the causes.

·         Issue action notes to the Contractor who is responsible for the works.

·         Implement remedial and corrective actions immediately.

·         Re-inspect the site conditions upon completion of the remedial and corrective actions.

·         Record the event and discuss with the Contractor for preventive actions.

 

Compliance Audits

 

3.6               Monitoring of the quality of effluent from the Works Areas, if any, is required during the construction phase of the Project. The monitoring shall be carried out at the pre-determined discharge point. Compliance audits are to be undertaken to ensure that a valid discharge licence has been issued by EPD prior to any discharge of effluent from the Project site. The monitoring frequency and parameters specified in the discharge licence shall be fully considered during the monitoring. All monitoring requirements shall be approved by EPD. The audit results reflect whether the effluent quality is in compliance with the discharge licence requirements. In case of non-compliance, suitable actions shall be undertaken to:

·         Notify the site management for the non-compliance.

·         Identify the sources of pollution.

·         Check the implementation status of the recommended mitigation measures.

·         Investigate the operating conditions of the on-site treatment systems.

·         Implement corrective and remedial actions to improve the effluent quality.

·         Increase monitoring frequency until the effluent quality is in compliance with the discharge licence requirements.

·         Record the non-compliance and propose preventive measures.

 

3.7               The implementation schedule for the recommended water quality mitigation measures is presented in Appendix A.

 

 

Waste Water Quality Control and Mitigation Measures

 

Construction Phase

 

3.8               Mitigation measures for water quality control have been recommended in the EIA Report.  The Contractor should be responsible for the design and implementation of these measures.

 

3.9               Recommended mitigation measures to minimise the adverse impacts on water quality during construction and operation phases are detailed in Sections 3.10 to 3.17 below.Mitigation measures for waste management are summarised below.  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 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.

 

Construction Site Runoff and General Construction Activities

 

3.10            The practices outlined in ProPECC PN 1/94 Construction Site Drainage should be adopted where applicable, to minimise the potential water quality impacts from construction site runoff and various construction activities.

 

3.11            There is a need to apply to EPD for a discharge licence for discharging effluent from the construction site, if any. The discharge quality is required to meet the requirements specified in the discharge licence. Any wastewater generated from the works areas should be treated so that it satisfies all the standards listed in the Technical Memorandum on Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters (TM-DSS).

 

3.12            Good site practices should be adopted to collect the rubbish and litter on the construction sites so as to prevent the rubbish and litter from spreading from the site area.  It is recommended to clean the construction sites on a regular basis.

 

Sewage from Workforce

 

3.13            The presence of construction workers generates sewage.  The construction workers can make use of the existing toilet facilities within the MFT, as necessary. If required, sufficient portable chemical toilets should be provided in the works areas, and a licensed collector should be deployed for appropriate disposal and maintenance of the toilets on a regular basis.

 

3.14            Notices should be posted at conspicuous locations to remind the workers not to discharge any sewage or wastewater into the nearby environment during the construction phase of the Project. 

 

Accidental Spillage of Chemicals

 

3.1            The contractor must register as a chemical waste producer if chemical wastes would be produced from the construction activities. The Waste Disposal Ordinance (Cap 354) and its subsidiary regulations, in particular the Waste Disposal (Chemical Waste) (General) Regulation, should be observed and complied with for control of chemical wastes.

 

3.15            Any service shop and maintenance facilities should be located within a bunded area, and sumps and oil interceptors should be provided. Maintenance of equipment involving activities with potential for leakage and spillage should only be undertaken within the areas appropriately equipped to control these discharges.

 

3.1Disposal of chemical wastes should be carried out in compliance with the Waste Disposal Ordinance. The Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes published under the Waste Disposal Ordinance details the requirements to deal with chemical wastes. General requirements are given as follows:

·Suitable containers should be used to hold the chemical wastes to avoid leakage or spillage during storage, handling and transport.

·Chemical waste containers should be suitably labelled, to notify and warn the personnel who are handling the wastes, to avoid accidents.

·Storage area should be selected at a safe location on site and adequate space should be allocated to the storage area.

 

Operational Phase

 

Handling of Site Drainage and Effluent

 

3.16            For handling, treatment and disposal of operational stage effluent, the practices outlined in ProPECC PN 5/93 should be adopted where applicable.  The following relevant recommendations should be followed:

 

·         Drainage outlets provided in open areas and areas subjected to a substantial amount of wind-blown rain should be connected to storm drains.

·         Drainage outlets provided in covered areas, including covered podiums and other roofed areas, should be discharged to foul sewers.

·         Surface water drainage should be provided for discharging storm water from open surfaces.  Such drainage as normally collected in open surface channels should be led to storm water drains via silt removal facilities.  Runoff in channels of building platforms should pass through a gully pit with necessary gratings to prevent objects from entering the storm water drains.

 

201846 such as Fire Services Department (FSD)

 

Good Site Practices

 

3.1Recommendations 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 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;

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

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

 

General Refuse

 

3.1General refuse should be stored in enclosed bins or compaction units.  A reputable waste collector should be employed by the contractor to remove general refuse from the site.  An enclosed and covered area is preferred to reduce the occurrence of 'wind blown' light material. 

 

Chemical Wastes

 

3.1If 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 explosive, flammable, oxidizing, irritant, toxic, harmful, corrosive, etc.  The Contractor shall use a licensed collector to transport and dispose of the chemical wastes, to either the Chemical Waste Treatment Centre at Tsing Yi, or another licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation

Good Site Practices

 

3.1It 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.

 

3.1In 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

 

3.1Good 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.

 

3.1In 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

 

3.1In 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.

 

3.1When 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

 

3.1If 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

 

3.1General 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.