15.1 Impact Summary for Tsang Tsui Ash Lagoon Site
15.1.1.1 This EIA Report has provided an assessment of the potential environmental impacts associated with the construction and operation of the IWMF at the TTAL site, with the consideration of the potential cumulative impact from other concurrent projects in the vicinity of the TTAL site. Specific mitigation measures requirements for the Project, as well as an environmental monitoring and auditing programme, have been developed. A summary of the environmental impacts associated with the Project are presented below.
15.1.2.1 Air quality impacts from the construction works for the Project would mainly be related to construction dust from excavation, materials handling, filling activities and wind erosion. With the implementation of mitigation measures specified in the Air Pollution Control (Construction Dust) Regulation, dust impact on air sensitive receivers would be minimal.
15.1.2.2 During the operation of the IWMF, the potential sources of air quality impact would be the air emissions from the incinerator stacks and the odour nuisance from the waste reception halls, the waste storage area, the mechanical treatment plant and the wastewater treatment plant.
15.1.2.3
Advanced air pollution control system, including
SCR for NOx removal and
activated carbon for dioxins removal and continuous emissions monitoring
system will be installed for the IWMF to ensure that the emissions from the
IWMF stacks will meet the target emission limits that are more stringent than
those stipulated in
15.1.2.4
Cumulative air quality impact assessment has
been undertaken for the Project at the
TTAL site taking into
account the emissions from both regional and local sources, including the
emissions within the Pearl River Delta Economic Zone and major local air
pollution sources in
15.1.2.5 Besides, odour nuisance may arise from the operation of the on-site wastewater treatment plant, the waste reception halls, the waste storage area and the mechanical treatment plant of the IWMF. The wastewater treatment plant, the waste reception halls and the waste storage areas would be fully enclosed and the odorous air in this facility would be extracted and used as combustion air for incineration to remove the odorous compounds. For the mechanical plant, they would be equipped with deodorizing system of 95% odour removal efficiency. Besides, the wastewater treatment plant, waste reception halls, waste storage area and mechanical treatment plant would also be operated under negative pressure to prevent odour leaking to the outdoor environment. The predicted cumulative odour concentrations would comply with the criteria required in the EIAO-TM. Adverse odour impact on nearby ASRs would not be expected.
15.1.3.1 The TTAL site is situated in a remote location and no existing or planned noise sensitive receiver (NSR) is identified within 300m from the boundary of the site. Adverse noise impacts from the TTAL site on NSRs during both construction and operation phases are therefore not anticipated.
15.1.3.2
Having said that, an assessment has been
undertaken to examine the potential traffic noise impact on the NSRs along
Construction Phase
15.1.4.1 The potential sources of water quality impact arising during the construction phase of the Project include construction site runoff and drainage, wastewater generated from general construction activities and sewage from the workforce. With implementation of the recommended mitigation measures and site practices outlined in ProPECC PN 1/94 (Practice Note for Professional Persons on Construction Site Drainage), no unacceptable residual impacts on water quality are expected.
Operation Phase
15.1.4.2 During the operation phase, wastewater will be generated from the proposed incineration plant and mechanical treatment plant. An on-site wastewater treatment plant will be provided. All generated wastewater will be discharged to the on-site wastewater treatment plant for treatment. The treated effluent from the wastewater treatment plant will be reused in the incineration plant and mechanical treatment plant or for washdown and landscape irrigation within the IWMF site. A “net zero discharge” scheme will be adopted during the operation of the IWMF.
15.1.4.3 An on-site desalination plant will be provided for supplying water to the IWMF. Saline water would be discharged from the desalination plant at a low discharge rate. The saline water has been quantitatively assessed to be minor and acceptable. Adverse impacts on water quality due to the saline water discharge would not be expected.
15.1.5 Waste Management Implications
Construction Phase
15.1.5.1
The types of waste that would be generated
during the construction phase of the Project include construction and
demolition (C&D) materials from the construction activities, general refuse
from the workforce and chemical wastes from the maintenance of construction plant and
equipment. Provided that the wastes are
handled, transported and disposed of properly and good site practices and waste
reduction measures are implemented accordingly, adverse environmental impact is
not expected during the construction phase of the Project.
Operation Phase
15.1.5.2 The end product from the incineration process of the IWMF would include bottom ash, fly ash and air pollution control residues, which would be disposed of at a landfill after checking for compliance with the proposed incineration residue pollution control limits. Pre-treatment of fly ash and air pollution control residues will be undertaken prior to disposal at landfill. A small amount of non-combustible inert refuse (e.g. glass, sand, residual metals etc.) sorted out in the mechanical treatment process would also be disposed of at the WENT Landfill.
15.1.5.3 Limited amount of chemicals or chemical wastes would be used or generated for the operation of the IWMF. With proper implementation of the recommended practices and response procedures on land contamination prevention, the potential for land contamination due to the IWMF operation is expected to be minimal.
15.1.6.1 The major ecological impact of the Project would be the loss of about 11 hectares of ash lagoon habitat, of which about 82% is usually dry and support scarce vegetation which has a low biodiversity and ecological value. The loss of the remaining ash lagoon with low to moderate ecological value including 1.98 hectares breeding ground of Little Grebe would be mitigated by the provision of about 1.2 ha permanent pond habitat within the IWMF site and the existing WENT Landfill, as well as the interim habitat enhancement work for about 4.5ha of the southern unoccupied Middle Lagoon. Disturbance impact to the breeding activities of Little Grebe would be minimized by scheduling the commencement of site formation work in the dry season. As a precautionary measure, the works area would be thoroughly inspected by experience ecologist(s) to confirm no breeding activities of Little Grebe would be affected by the construction work before commencement of site clearance.
15.1.6.2 Other indirect impacts would include noise and human disturbance, release of PFA leachate and construction site runoff and wastewater. With proper implementation of good site practices including the use of quiet machinery to reduce noise emissions, proper drainage arrangement to minimize construction runoff etc., adverse ecological impact is not anticipated. The implementation of mitigation measures would be subject to regular audit as part of the EM&A programme.
Operation Phase
15.1.6.3 No direct habitat loss would be resulted from the operation of the proposed Project. Disturbance impacts would include human activities and noise due to increased operational traffic. Mitigation measures such as landscape planting and boundary wall have been recommended to screen the visual interface and to limit public access to the adjoining lagoon habitat. The ecological function of the recreated pond as an alternative habitat for Little Grebe will be monitored.
15.1.6.4 With the implementation of the recommended mitigation measures, no unacceptable ecological impact due to the operation of the proposed Project would be expected.
15.1.7.1
No loss of fishing ground and resources is
expected during construction and operation phases of the proposed Project. The construction of the IWMF would be mainly
land-based with only minor work anticipated at the seawall for the construction
of the saline water outfall. No unprocessed or processed effluent would be discharged into the
15.1.8.1 The cancer risk arising from exposure to compounds of potential concern (COPCs) associated with the emissions of the IWMF has been evaluated in this EIA Study. The highest incremental (excess) cancer risk arising from the IWMF is predicted to be 1.26x10-6 which is within the screening level of 1x10-5 adopted by USEPA and it is considered that the Project would not present an unacceptable risk and no further analysis is necessary. The highest predicted total Hazard Index (HI) at all receptors are well below 0.25, which is an initial screening exposure benchmark derived from a conservative approach by the USEPA. Cumulative acute non-carcinogenic health impact of the IWMF imposed to the worst impacted human receptors were assessed and compared with local and overseas guideline levels. It was concluded that the levels of non-carcinogenic chemicals were found to be insignificant when compared to the adopted/derived reference levels. For the classical COPCs of the HKAQO, while it is not possible to rule out adverse health effects from the IWMF with complete certainty, the impact on health from small additional air pollutants is likely to be very small and unlikely to be quantifiable.
15.1.8.2
As the vast majority of foods in
15.1.8.3 The existing practices of transporting wastes in enclosed containers will be followed. With regards to the storage and handling of waste and ash, given that all the reception halls and ash storage pits will be fully enclosed with slightly negative air pressure and a closed grab will be use to grab waste and ash. Leakage of any fugitive emissions to the outdoor environment is not expected. With the implementation of the recommended health risk control measures, the potential health impacts associated with the transportation, storage and handling of waste and ash are considered to be insignificant.
15.1.8.4 The potential health risk induced by radon emissions associated with PFA arising from the construction and operation was also evaluated. The estimation indicated that there would be no significant radiological hazard to workers working outdoors in the IWMF or in the restored/ operating ash lagoon area adjacent to the IWMF.
15.1.8.5 The IWMF will be designed and operated to the most up-to-date standards and practices. The operator must be well trained to avoid any accidental events as well as to implement industry best practice with reference to international standards and guidelines. To avoid or minimize the potential health impacts associated with potential accidental events, an emergency response plan will be developed and properly implemented for the IWMF. It should be noted that the emergency response plan should be specific to the final design and operation of the IWMF. The recommended preventive measures include the use of best available techniques, continuous and regular stack emission monitoring, as well as conducting regular safety monitoring and audit. With the implementation of the recommended preventive measures and an effective emergency response plan for the IWMF, the health impacts associated with any potential accidental events could be minimized if not avoided.
15.1.9 Landscape and Visual Impact
15.1.9.1 During the construction phase, the impact to the landscape resources and landscape character areas would be “insubstantial”, except the Ash Lagoon (LR1 & LCA1). The impact to the Ash Lagoon (LR1 & LCA1) before mitigation would be “substantial”.
15.1.9.2 During the operation phase, the proposed works has negligible impact to most of the landscape resources and landscape character areas, except the Ash Lagoon (LR1 & LCA1) where the project site locates. The impact to the Ash Lagoon would be “substantial”. Mitigation measures including proper landscape design blending the facilities into the surroundings, rooftop/vertical greening design, landscape treatment, provision of compensatory habitat for Little Grebe, etc. are anticipated to mitigate the landscape impact and enhance the overall landscape quality of the environment. The long-term residual impact to the Ash Lagoon would be reduced to “slight” in both day 1 and year 10 of operation.
15.1.9.3 Surrounded by facilities of similar nature (e.g. STF, Black Point Power Station), the development of the IWMF at the TTAL site is considered compatible with the surrounding context. With the landscape design of the IWMF being coherent with the adjacent STF, the development of the two facilities could be integrated and blend well in the surrounding landscape. The two developments would form a harmonic view, and the cumulative landscape impact of the two developments would be alleviated. Another concurrent project is the WENT Landfill Extension. The construction phase of the IWMF will occur concurrently during the early construction phase of the WENT Landfill Extension while the operation phase of the IWMF will occur during the construction, operation, restoration and aftercare phases of the WENT Landfill Extension. The construction and operation of the WENT Landfill Extension will cause significant cumulative impact to the area due to large-scale site formation. During the restoration & aftercare phases of the WENT Landfill Extension, the IWMF and STF would be in Year 8 and Year 11 of the operation phase respectively. The mature advanced planting at the WENT Landfill Extension can act as screening effect for the WENT Landfill Extension, and the compensatory planting at the WENT Landfill Extension will be provide preliminary vegetation cover for site area of the WENT Landfill Extension. The WENT Landfill Extension will become compatible with the surrounding IWMF and STF in which various landscape mitigation measures, such as landscape planting, green roof, vertical greening, have been implemented for a substantial period of time. After the whole period of restoration and aftercare phases of the WENT Landfill Extension, the impact due to the WENT Landfill Extension would be greatly mitigated by semi-mature compensatory woodland, shrubland and grassland. The IWMF, STF and resorted WENT Landfill Extension would blend well and be merged as a whole. No significant residual cumulative impact is anticipated.
15.1.9.4
The visual impact to most of the visual
sensitive receivers during the construction phase would be “moderate”, and the
visual impact to sea travellers of Deep Bay (VSR4) would be “substantial”.
After the implementation of the mitigation measures, the residual impact to the
sea travellers of
15.1.9.5 The visual impact to most of the visual sensitive receivers during the operation phase would be “moderate”, and the visual impact to the residents/visitors of Ha Pak Lai (VSR5) and the sea travellers of Deep Bay (VSR4) would be “moderate/substantial” and “substantial” respectively. After the implementation of the proposed mitigation measures, the residual impact to most of the visual sensitive receivers would be reduced to “slight”, and the residual impact to the residents/visitors of Ha Pak Lai (VSR5) and the sea travellers of Deep Bay (VSR4) would be “slight/moderate” in year 10 of operation.
15.1.9.6 Regarding the visual impacts during waste transportation / handling and its cumulative visual impacts, the impact is expected to be insignificant. During the operation stage, MSW will be contained in containers and transported to the berth of WENT Landfill from the Refuse Transfer Stations (RTSs) through marine transport. This is the current mode of transportation to transfer MSW from the RTSs to the WENT Landfill. After arriving berth of the WENT Landfill, the container will be transported to the IWMF by land transport and MSW will then be discharged from the containers to the bunker at the IWMF reception hall, which is enclosed in a covered building. The potential visual impact due to waste transportation / handling is anticipated to be minimal.
15.1.9.7 As mentioned in Section 15.1.9.3, the development of the IWMF at TTAL is surrounded by facilities of similar nature (e.g. STF, Black Point Power Station). The IWMF is considered compatible with the surrounding context. With the architectural and landscape design of the IWMF being coherent with the adjacent STF, the development of the two facilities could be integrated and blend well in the surrounding landscape. The two developments would form a harmonic view, and the cumulative visual impact of the two developments would be alleviated.
15.1.9.8 In conclusion, the potential landscape and visual impacts can be effectively reduced by implementing the proposed mitigation measures during construction and operation phases. With reference to criteria defined in Annex 10 of the EIAO TM, the overall residual impact is considered as “acceptable with mitigation measures” after implementing the mitigation measures.
15.1.10 Impact on Cultural Heritage
15.1.10.1 Based on the results of the desktop review and survey, the Tsang Tsui Archaeological Site has a high archaeological potential. However, the Tsang Tsui Archaeological Site is located approximately 150m from the Project boundary and adverse impacts associated with this Project are not expected.
15.1.10.2
The Hung Shing and
15.1.11 Landfill Gas Hazards Assessment
15.1.11.2 A number of measures have been recommended for the Project to safeguard the safety of all personnel and the general public (i.e. visitors) present at the Project site during construction and operation phase. These include site safety measures and routine monitoring of landfill gas at excavation areas during construction phase, and installation of gas barrier and monitoring wells and other building protection measures as necessary during the operation phase. With the implementation of these measures, no adverse impact of landfill gas hazard on this Project is anticipated.
15.1.12 Summary of the Measures Taken for the Minimization of Environmental Impacts
15.1.12.1 The various chapters and appendices of this EIA report have presented the measures to minimize pollution in the planning, design, construction and operation stages. The key measures to minimize pollution are summarized below for easy reference and they are not exhaustive. For details, please refer to the relevant chapters and appendices as appropriate.
Adoption of Modern Incineration Technologies
15.1.12.2 The IWMF will employ modern incineration technologies including advanced process controls to optimize the combustion process and to achieve complete combustion of the MSW, proper breakdown of hazardous organic substances (e.g. volatile organics, dioxins) and pathogens (e.g. fungi, bacteria and viruses) in the MSW and prevent formation of new pollutants. The flue gases will be maintained at a temperature of over 850oC in the presence of a surplus of oxygen for adequate residence time (at least 2 seconds) and with high turbulence for better mixing in the combustion chamber. This is the so-called 3T incineration technology being adopted in modern moving grate incinerators. Coupled with advanced gas cleaning and pollution abatement equipment such as fabric filters, scrubbers and activated carbon powder injection system which effectively control the release of pollutants, the IWMF will meet the stringent emission limits stipulated by the European Commission for waste incineration. In addition, the IWMF will be installed with advanced air pollution control system namely selective catalytic reduction (SCR) for nitrogen oxides (NOx) removal. With the adoption of the SCR process, the daily average emission limit of NOx is lowered to 100 mg/m3, which is a 50% reduction when compared with the European Union (EU) standard.
Use of Cooling System
15.1.12.3 The heat energy of the air getting out from the furnace is transmitted to water, converting the water to high pressure steam. The high pressure steam is used to rotate a steam turbine and generate electricity. After the electricity generation process, the high pressure steam becomes low pressure steam, which is further cool down by a cooling system. Alternative cooling systems, including water-cooled condenser and air-cooled condenser, were considered. A water-cooled condenser involves exchange of the heat of the low pressure steam to water, which is then discharged to the nearby water body. An air-cooled condenser involves exchange of the heat of the low pressure steam to air, which is then discharged to the atmosphere. To minimize the potential impact to the nearby water bodies due to discharge of cooling water, air-cooled condenser was adopted in the IWMF. Another advantage of air-cooled condenser is water consumption will be greatly reduced.
Layout Arrangement
15.1.12.4 With a view to minimize the land use and the associated environmental impacts the layout for the IWMF is considered appropriate taking into consideration the functional need for operation of the IWMF, reasonable flexibility in design for future DBO contractor and allowance of suitable size of land for provision of visitors and community facilities. Based on the proposed layouts, the footprint requirement for treating per tonnage of MSW daily is approximately 32m2 at the TTAL site. The area for compensated habitat for Little Grebe at the TTAL site was excluded in this unit footprint calculation.
15.1.12.5 The unit footprint requirement of the IWMF is comparable with other overseas incineration plants, including Afval Energie Bedrijf (AEB) Incineration Plant with design capacity of 4,000 tpd in Netherland and Tokyo Edogawa Incineration Plant with design capacity of 600 tpd in Japan. Based on the existing overseas installations, the footprint requirement for treating per tonnage of MSW daily is normally in the range of 30m2 to 40m2 subject to the area provided for other uses including visitors and community facilities.
Construction Methods
15.1.12.6 To minimize the potential environmental impacts, alternative construction methods were considered. For the piling works at the TTAL site, percussive piles and socketted H-piles were considered. Percussive piles would cause substantial noise and vibration impacts, whereas the noise and vibration impacts due to the construction of socketted H-piles would be significantly lower. Considering the environmental benefits and dis-benefits of the alternative piling methods, socketted H-piles is recommended for this Project to minimize the potential noise impact during the construction.
15.1.12.7 Mitigation measure requirements specified for other environmental aspects are summarized below.
Measures for Air Quality
· Implementation of mitigation measures stated in the Air Pollution Control (Construction Dust) Regulation to minimize dust impacts during construction phase
· Installation of advanced air pollution control system, including SCR for NOx removal and activated carbon for dioxins removal and continuous emissions monitoring system
· 150m is selected as the stack height for the IWMF to alleviate the potential air quality impacts at critical air sensitive receivers (ASRs) due to adverse terrain and building wake effects
· All odorous gases from the wastewater treatment plant, the waste reception halls and the waste storage areas would be fully enclosed and the odorous air in this facility would be extracted and used as combustion air for incineration to remove the odorous compounds
· Mechanical plant would be equipped with deodorizing system of 95% odour removal efficiency
· The IWMF facilities would be operated under negative pressure to prevent odour leaking to the outdoor environment
Measures for Water Quality
· Implementation of the recommended mitigation measures and site practices outlined in ProPECC PN 1/94 (Practice Note for Professional Persons on Construction Site Drainage) to minimize construction phase impacts
· Provision of on-site wastewater treatment plant. The treated effluent from the wastewater treatment plant will be reused in the incineration plant and mechanical treatment plant or for washdown and landscape irrigation within the IWMF site.
· A “net zero discharge” scheme will be adopted during the operation of the IWMF
· A pipeline drainage system will serve the project site collecting surface runoff from paved areas, roof, etc. Sustainable drainage principle would be adopted in the drainage system design to minimize peak surface runoff, maximize permeable surface and maximize beneficial use of rainwater.
· Oil interceptors will be provided in the drainage system of any potentially contaminated areas (such as truck parking area and maintenance workshop) and regularly cleaned to prevent the release of oil products into the storm water drainage system in case of accidental spillages. Accidental spillage will be cleaned up as soon as practicable and all waste oils and fuels will be collected and handled in compliance with the Waste Disposal Ordinance.
Measures for Waste Management
· To avoid offsite disposal of C&D materials, the excavated PFA will be totally reused as filing material within the IWMF site area
· Implementation of the recommended mitigation measures and site practices outlined in ETWB TCW No. 19/2005 & 31/2004 on construction waste management
· The end product from the incineration process of the IWMF will be disposed of at a landfill after checking for compliance with the proposed incineration residue pollution control limits. Pre-treatment of fly ash and air pollution control residues will be undertaken prior to disposal at landfill.
Measures for Ecology
· Measures to avoid mortality of Little Grebe
Ø Site formation work will be scheduled to commence in dry season.
Ø Hoarding and waterproof membrane will be set up between the work boundary and the unoccupied Middle Lagoon before backfilling
Ø As a precautionary measure, the whole Project site will be thoroughly inspected twice at the earliest two weeks prior the proposed commencement date of construction activities to confirm no breeding activities of Little Grebe (including their eggs, chicks and juveniles) would be affected by the construction activities. The inspection will be performed by experienced ecologist(s) with over seven year experience in the relevant aspect. Agriculture, Fisheries and Conservation Department (AFCD) will be informed in writing about the suitability of commencing construction work at the Project site before the commencement of any site activities.
Ø If breeding activities of Little Grebe are found during site inspection, the construction programme and method shall be reviewed.
· Measures to avoid loss of gorgonians
Ø The location of the saline water outfalls has been refined away from gorgonians so as to avoid any direct impact to the gorgonians
· Measures to minimize disturbance impact to wildlife
Ø Hoarding of at least 3 m high will be set up along the southern and western boundary of the works areas during the formation of the additional compensatory habitat and associated site access to shield the fauna in the Middle Lagoon and other natural habitats from the visual disturbance by human activities during construction phase. After the establishment of the additional compensatory habitat, the hoarding at the western boundary will be disassembled. New hoarding will be set up between the additional compensatory habitat and the site.
Ø The works boundaries will be confined within the proposed project site. All work crews and equipment will be restricted within the designated works area only. Any personnel will be prohibited to encroach or wilfully disturb any wild animals and their habitats. Traffic and human access from the western side of the project site will be avoided.
Ø Boundary walls of at least 3.5 m high with climbing planting or plantation will be provided, where practicable, along the southern of the project site and between the access road and the additional compensatory habitat for Little Grebe, to screen the surrounding habitats from the IWMF works areas
· Measures to minimize impacts to natural habitats
Ø The site formation work will be scheduled to the dry season when the water level in the Middle Lagoon is minimal
· Minimize sedimentation/water quality impacts to waterbodies
Ø To minimize the potential water quality impacts from the construction works located at or near any seafront, the practices outlined in ETWB TC (Works) No. 5/2005 Protection of natural streams/ rivers from adverse impacts arising from construction works will be adopted where applicable.
· Minimize general disturbance during construction phase
Ø Placement of equipment or stockpile in designated works areas, and selection of access routes on existing disturbed land to minimize disturbance to the unoccupied ash lagoons or natural habitat
Ø Construction activities will be restricted to works areas that would be clearly demarcated. Access to areas of the ash lagoon outside the works areas will be strictly prohibited.
Ø The works areas will be reinstated immediately after completion of works
Ø Waste skips will be provided to collect general refuse and construction wastes. The wastes will be disposed of timely and properly off-site.
Ø Drainage arrangements will include sediment traps to collect and control construction run-off
Ø Open burning on works sites is illegal, and will be strictly prohibited. Temporary fire-fighting equipment in the works areas will be provided to prevent any open fire.
Ø Fences along the boundary of works areas will be provided before the commencement of works to prevent tipping, vehicle movements and encroachment of personnel into adjacent areas.
· Minimize noise disturbance
Ø Noise mitigation measures including the use of quieter piling machinery and construction plants and full enclosure for static plant will be implemented to lower the noise level due to construction works
Ø Only well-maintained plant will be operated on site and plant will be serviced regularly during the construction programme
Ø Machines and plant which may be in intermittent use will be shut down between work periods or shall be throttled down to a minimum
Ø Plant known to emit noise strongly in one direction, will, where possible, be orientated so that the noise is directed away from the southern and western end of site boundary
Ø Silencer or mufflers on construction equipment will be utilized and will be properly maintained during the construction period
Ø Mobile plant (such as generator) will be sited as far away from the southern and western end of site boundary as possible
Ø Material stockpiles and other structures will be effectively utilized, where practicable, to screen noise from on-site construction activities
· Measures to create pond habitat for Little Grebe
Ø Permanent water pond with a size of about 1 ha for Little Grebe will be constructed at western side of the IWMF Project site at the early stage of construction phase
Ø The water depth will be maintained between 0.8 m to 1.5 m
Ø Consistent water source will be secured
Ø Appropriate type and species of aquatic plants will be planted to provide sustainable supply of food for Little Grebes
Ø The water quality of the pond will be maintained for the growth of the aquatic plants and associated wildlife including Little Grebe’s food sources
Ø Emergent vegetation will be planted to provide habitats for amphibian and dragonflies
Ø The slope of pond bund will be profiled to provide gentle gradient from about 1:4 to 1:6 to facilitate the growth of emergent plants
Ø To screen out the breeding population from disturbance due to nearby traffic, native vegetation will be planted at the boundary of the pond as appropriate, and boundary walls planted with climbers will be set up between the recreated pond and the access road
Ø Floating raft with special design for the breeding requirement of Little Grebe will be installed to enhance its breeding habitat
Ø Prior to the construction of the pond(s), a Habitat Creation and Management Plan (HCMP) of the pond(s) will be prepared by experienced ecologist possesses at least a Bachelor’s degree in relevant discipline and at least 7 years relevant professional experience. The HCMP will be circulated to relevant departments including AFCD.
· Measures to enhance the southern unoccupied Middle Lagoon portion
Ø The southern unoccupied Middle Lagoon portion with a size of 4.5 ha will be maintained as an enhanced wetland habitat
Ø No PFA filling activities will be allowed
Ø Freshwater source to the enhanced wetland habitat will be secured, and the water level of the enhanced wetland habitat will be regulated to provide a more stable wetland area
Ø Floating raft with special design suiting with Little Grebe’s breeding requirement will be installed
Ø Prior to the habitat enhancement work, a Habitat Creation and Management Plan (HCMP) of the enhancement work will be prepared by experienced ecologist possesses at least a Bachelor’s degree in relevant discipline and at least 7 years relevant professional experience. The HCMP will be circulated to relevant departments including AFCD.
Measures for Health Impact
· The air quality measures described above will also minimize the potential health risk associated with air emissions from the IWMF
· Prevention of radon influx from PFA to the IWMF buildings
Ø A soil cover can be provided beneath the buildings on top of ash lagoon prior to construction works because it reduces the level of radon influx significantly
Ø Slab-on-grade can be an option on foundation design
Ø Soil suction can also prevent radon from entering the building by drawing the radon from below the building and venting it through a pipe, or pipes, to the air above the building
· Provision of sufficient ventilation of interior of IWMF buildings
Ø Forced and natural ventilation will be introduced properly to enhance air exchange rate in the IWMF buildings
Ø Basement areas could be pressurized by using a fan to blow air into the basement areas from outdoors. This would create enough pressure at the lowest level indoors to prevent radon from entering into the IWMF buildings.
· Regular maintenance for floor slabs and walls
Ø Cracks and other openings in the foundation will be properly sealed to reduce radon ingress
Ø Sealing the cracks limits the flow of radon into the building thereby making other radon reduction techniques more effective and cost-efficient. It also reduces the loss of conditioned air.
· Radon concentration measurement prior to occupation of IWMF buildings
Ø Radon concentration will be measured by professional persons in accordance with EPD’s ProPECC Note PN 1/99 Control of Radon Concentration in New Buildings Appendix 2, ”Protocol of Radon Measurement for Non-residential Building” to ensure the radon concentration is in compliance with the guidance value
Measures for Landscape and Visual Impact
· All bare soil surface will be grass-hydroseeded
· Provision of water pond as habitat for Little Grebe
Ø A compensatory habitat for Little Grebe will be provided as an ecological mitigation measure for the loss of habitat within the project site. This compensatory habitat, which would be a landscape area with water pond and plants, is also considered as a landscape mitigation measure for the loss of ash lagoon. The final design of the habitat will be determined in the Habitat Creation and Management Plan.
· Existing trees preservation within works areas
Ø No trees will be felled or transplanted unless they are inevitably affected by the proposed works. Affected trees will be transplanted under circumstance where technically feasible. A tree survey report will be prepared and a tree felling application will be submitted to Government during the detailed design stage for approval before the site formation works commence. The numbers, locations, species and sizes of the trees to be transplanted or felled will be clearly addressed. All existing trees within work sites will be properly maintained and protected for their crowns, trunks and roots.
· Transplanting of trees to adjacent locations
Ø The existing trees recommended to be transplanted will be directly transplanted to other locations in vicinity where no construction will take place
Ø The construction programme will allow sufficient time for root pruning and rootball preparation prior to transplanting
· Compensatory landscape planting
Ø Implementation of compensatory planting with heavy standard trees will be of a ratio not less than 1:1 according to tree quantity and total tree trunk diameter lost
· Landscape design
Ø Early planting using fast grow trees and tall shrubs at strategic locations within site will be implemented to block view corridors to the site from the VSRs, and to locally screen haul roads, excavation works and site preparation works
Ø Tree species of dense tree crown will be used to serve as visual barrier
Ø Hard and soft landscape treatment (e.g. trees and shrubs) of open areas within development will be implemented to provide shade and shelter and a green appearance from surrounding viewpoints
Ø Planting strip would be provided along the periphery of the project site
Ø Selected plant species will be suitable for coastal condition
· Reuse existing boulders
Ø Boulders cleared from the ash lagoon during site formation will be reserved and used as part of the landscape design to preserve its “natural look”
· Greening design (rooftop & vertical greening)
Ø Rooftop and vertical greening (vertical building envelope) will be implemented to increase the amenity value of the proposed works, moderate temperature extremes and enhance building energy performance, as well as visually improve the development
Ø Vertical greening will be implemented for the lower portion of chimney (~20-25m high)
· Visual mitigation and aesthetic design
Ø Recessive colour tone is proposed for the façade of the ancillary facility buildings (e.g. incinerator plant) to blend in with the nature
Ø Architectural feature (e.g. light weight aluminum structure) is incorporated with the tapered chimney of recessive colour tone to diminish its “chimney like” appearance
Ø Stone as a natural material is proposed at the lower portion of the building façade and the chimney to compliment with the surrounding environment
Ø Change of material at different portions of the building helps to reduce the bulkiness
Ø Green roof structure (with irrigation and drainage system) in curvilinear strips is proposed to cover the rectilinear building bulk. Roof strips of different curvatures are further broken down to echo with the contour of the hillside slope behind.
· Security floodlight for construction areas will be controlled at night to avoid excessive glare to the surrounding receiver
· The construction sequence and construction programme will be optimized in order to minimize the duration of impact
· The backfilling materials for site formation & construction materials / wastes on site will only be stored to a maximum height of 2m and covered with an impermeable material of visually un-obtrusive material (in earth tone)
· The number of construction traffic to / from the project site will be maintained to practical minimum
· Planting maintenance
Ø Proper planting maintenance and replacement of defective plant species on the new planting areas to enhance aesthetic and landscape quality will be provided
· Control of light
Ø The numbers of lights and their intensity will be controlled to a level good enough to meet the safety requirements at night but not excessive
· Control of operation time
Ø The frequency of waste transportation will be minimized to practical minimum (e.g. limit the reception of MSW from 8 am to 8 pm)
Measures for Landfill Gas Hazard
15.1.12.8 A number of measures have been recommended for the Project to safeguard the safety of all personnel and the general public (i.e. visitors) present at the Project site during construction and operation phase. These include site safety measures and routine monitoring of landfill gas at excavation areas during construction phase, and installation of gas barrier and monitoring wells and other building protection measures as necessary during the operation phase.
15.2 Impact Summary for the IWMF at an artificial island near SKC
15.2.1.1 This EIA Report has provided an assessment of the potential environmental impacts associated with the construction and operation of the Project at an artificial island near Shek Kwu Chau (SKC), with the consideration of the potential cumulative impact from other concurrent projects in the vicinity of the artificial island near SKC. Specific mitigation measures requirements for the Project, as well as an environmental monitoring and auditing programme, have been developed. A summary of the environmental impacts associated with the Project are presented below.
15.2.2.1
Air quality impacts from the construction works
for the Project would mainly be related to construction dust from excavation,
materials handling, filling activities and wind erosion. With the implementation of mitigation
measures specified in the Air Pollution Control (Construction Dust) Regulation,
dust impact on air sensitive receivers would be minimal.
Operation Phase
15.2.2.2 During the operation phase, the potential sources of air quality impacts would be the air emissions from the incinerator stacks and the odour nuisance from the waste reception halls, the waste storage area and the mechanical treatment plant.
15.2.2.3
Advanced air pollution control system, including
SCR for NOx removal and activated carbon for dioxins removal and continuous
emissions monitoring system will be installed for the IWMF to ensure that the
emissions from the IWMF stacks will meet the target emission limits that is
more stringent than those stipulated in
15.2.2.4
Cumulative air quality impact assessment has
been undertaken for the Project at the artificial island near SKC. The cumulative air quality impact assessment
has taken into account the emissions from both regional and local sources,
including the emissions within the Pearl River Delta Economic Zone and major
local air pollution sources in
15.2.2.5 Besides, odour nuisance may arise from the operation of the on-site wastewater treatment plant, the waste reception halls, the waste storage area and the mechanical treatment plant of the IWMF. The wastewater treatment plant, the waste reception halls and the waste storage areas would be fully enclosed and the odorous air in this facility would be extracted and used as combustion air for incineration to remove the odorous compounds. For the mechanical plant, they would be equipped with deodorizing system of 95% odour removal efficiency. Besides, the wastewater treatment plant, waste reception halls, waste storage area and the mechanical treatment plant would also be operated under negative pressure to prevent odour leaking to the outdoor environment. The predicted cumulative odour concentrations would comply with the criteria required in the EIAO-TM. Adverse odour impact on nearby ASRs would not be expected.
15.2.3.1 The assessment results have demonstrated that daytime noise criteria would not be exceeded by the predicted construction noise levels under the unmitigated scenario. Having said that, good practices for the control of noise emissions from construction sites are recommended to further eliminate the potential of noise impact. These include good site practices to limit noise emissions at source and the use of quiet plant and working methods, whenever practicable.
15.2.3.2 Besides, a construction noise EM&A programme is recommended to check the compliance of the noise criteria during normal daytime working hours.
Operation Phase
15.2.3.3 Operation noise impacts from fixed plant noise can be effectively mitigated by including noise control treatment at the source during the design stage and implementing the same during operation. Adverse residual operation noise impacts are not anticipated. The need for noise measurement during commissioning of fixed noise sources should be included in the contract documents of the IWMF.
Construction Phase
15.2.4.1 The potential sources of water quality impact arising during the construction phase of the Project include construction site runoff and drainage, wastewater generated from general construction activities and sewage from the workforce. With implementation of the recommended mitigation measures and site practices outlined in ProPECC PN 1/94 (Practice Note for Professional Persons on Construction Site Drainage), no unacceptable residual impacts on water quality are expected.
15.2.4.2
To minimize dredging and filling activities and
the associated environmental impacts, cellular cofferdam and breakwater instead
of sloping seawall are proposed to be adopted.
Large-scale sediment dredging is therefore not anticipated for the
proposed reclamation and
breakwater construction works at the artificial
island near SKC. Only small-scale
dredging may be required along the proposed cofferdam to remove the top 1m of
clayey marine deposit for installation of an anti-scouring protection
layer. The water quality impact during
the dredging for anti-scouring protection layer has been quantitatively
assessed using the near field sediment dispersion model. The model results indicated that the water
quality impact generated from the dredging works would be localized and minor
under the mitigated scenario and would unlikely contribute to any significant
water quality impact. Mitigation
measures including the employment of silt curtain system, control of dredging
and filling rates etc. are proposed to ensure that no unacceptable water
quality impact would be resulted from the dredging works.
15.2.4.3
Besides, during installation of submarine
cables, the seabed sediment will be released at the bottom of the water column
which will result in high localized suspended sediment concentrations. An analysis has been undertaken to determine
the potential transport of fine sediments suspended into the water column
during the cable laying process. The
analysis results indicated that the sediment disturbed during laying of the
submarine cable will settle onto the seabed within approximately 80m of the
cable alignment. Since all the
identified water sensitive receivers are located beyond this impact zone and
the whole submarine cable installation works will be completed within a short
duration, the potential water quality impacts are considered short term and
acceptable.
Operation Phase
15.2.4.4
During the operation phase, wastewater will be
generated from the proposed incineration plant and mechanical treatment
plant. An on-site wastewater treatment
plant will be provided. All generated
wastewater will be discharged to the on-site wastewater treatment plant for treatment. The treated effluent from the wastewater
treatment plant will be reused in the incineration plant and mechanical
treatment plant or for washdown and landscape irrigation in the IWMF site. There would be no wastewater effluent
discharged to the coastal waters of
15.2.4.5 An on-site desalination plant will be provided for supplying water to the IWMF. Saline water would be discharged from the desalination plant at a low discharge rate. The saline water has been quantitatively assessed to be minor and acceptable. Adverse impacts on water quality due to the saline water discharge would not be expected.
15.2.5 Waste Management Implications
Construction Phase
15.2.5.1
The types of waste that would be generated
during the construction phase of the Project include dredged marine sediment,
construction and demolition (C&D) materials from foundation works and piling works, general refuse
from the workforce and chemical wastes from the maintenance of construction
plant and equipment. Provided that the
wastes are handled, transported and disposed of properly and good site
practices and waste reduction measures are implemented accordingly, adverse
environmental impact is not expected during the construction phase of the
Project.
Operation Phase
15.2.5.2
The end product from the incineration process of
the IWMF would be bottom ash, fly ash and air pollution control residues which
would be disposed of at landfill after checking for compliance with the
proposed incineration residue pollution control limits. Pre-treatment of fly ash and air pollution
control residues will be undertaken prior to disposal at landfill. A small amount of non-combustible inert
refuse (e.g. glass, sand, residual
metals etc.) sorted out in the
mechanical treatment process would also be disposed of at landfill.
15.2.5.3 Limited amount of chemicals or chemical wastes would be used or generated from 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 land contamination due to the IWMF operation is expected to be minimal.
15.2.6.1
The waters to the South of Lantau and
15.2.6.2
The key potential direct impacts identified
under the Project include the permanent loss of 31 hectares of important habitat
for Finless Porpoise, covering the reclamation and the embayment area within
breakwater. Mitigation measures proposed
to mitigate this loss include firm commitment from the Project Proponent to designate
an appropriate area of waters of about 700 hectares between Shek Kwu Chau and
15.2.6.3
A total of 198 coral colonies of small sizes and
low coverage (<1%), comprising 1 hard coral and 7 octocoral species, within
the proposed reclamation area may be directly affected. As all the corals to one uncommon species
that are located along the
15.2.6.4
The
15.2.6.5 Besides the above marine works, the construction of the Project also involves laying of submarine cables between Shek Kwu Chau and Cheung Sha as well as the construction of a landing portal at Cheung Sha. The benthos communities of the temporarily affected areas are expected to recolonise the seabed areas after the short period of submarine cable laying operation (about 20 working days). In view of the low to moderate ecological value of the subtidal habitats and temporary nature of the impact, the potential impact on subtidal habitat and the associated benthos communities due to submarine cable laying works is considered to be low. Moreover, considering the localized nature of sediment plume and short term duration of the works, as well as the natural adaption of fish, no significant impacts are expected on the potential fish spawning and nursery ground due to the submarine cable laying works. For the construction of Cheung Sha landing portal, considering the small scale of landing portal works, existing turbid condition, and absence of ecological sensitive receiver along the shoreline, with the adoption of good site practice and water quality control measures, potential impact on ecological resources during construction of Cheung Sha portal is considered to be acceptable.
15.2.6.6
Monitoring programmes for Finless Porpoise,
coral colonies, and
15.2.7.1 Permanent loss of 31 hectares of fishing ground, of which 15.9 hectares is a previously identified fisheries spawning and nursery ground, is expected. Indirect impact on fisheries due to elevation in suspended solids level during construction phase would be temporary and localized. Mitigation measures such as adoption of silt curtain, reduced dredging rate, and phasing of marine works have been recommended, in order to minimize adverse impact on water quality, hence protecting fisheries resources. During operation phase, although the rate of water intake for water supply at the desalination plant of the IWMF is slow, the potential impact from impingement and entrainment of fisheries resources would be further minimized by provision of screen at the seawater intake.
15.2.7.2 With the proper implementation of the recommended mitigation measures, potential impact on fisheries due to the Project is considered to be acceptable.
15.2.8.1 The cancer risk arising from exposure to compounds of potential concern (COPCs) associated with the emissions of the IWMF has been evaluated in this EIA. The highest incremental (excess) cancer risk arising from the IWMF is predicted to be 3.23x10-6 which is within the screening level of 1x10-5 adopted by USEPA and it is considered that the Project would not present an unacceptable risk and no further analysis is necessary. The highest predicted total Hazard Index (HI) at all receptors are well below 0.25, which is an initial exposure screening benchmark derived from a conservative approach by the USEPA. Cumulative acute non-carcinogenic health impact of the IWMF imposed to the worst impacted human receptors were assessed and compared with local and overseas guideline levels. It was concluded that the levels of non-carcinogenic chemicals were found to be insignificant when compared to the adopted/derived reference levels. For the classical COPCs of the HKAQO, while it is not possible to rule out adverse health effects from the IWMF with complete certainty, the impact on health from small additional air pollutants is likely to be very small and unlikely to be quantifiable.
15.2.8.2
As the vast majority of foods in
15.2.8.3 The existing practices of transporting wastes in enclosed containers will be followed. With regards to the storage and handling of waste and ash, given that all the reception halls and ash storage pits will be fully enclosed with slightly negative air pressure and that closed grab will be use to grab waste and ash, leakage of any fugitive emissions to the outdoor environment is not expected. With the implementation of the recommended health risk control measures, the potential health impacts associated with the transportation, storage and handling of waste and ash are considered to be insignificant.
15.2.8.4 The IWMF will be designed and operated to the most up-to-date standards and practice. The operator must also be well trained to avoid any accidental events as well as to implement industry best practice with reference to international standards and guidelines. To avoid or minimize the potential health impacts associated with potential accidental events, an emergency response plan will be developed and properly implemented for the IWMF. It should be noted that the emergency response plan should be specific to the final design and operation of the IWMF. The recommended preventive measures include the use of best available techniques continuous and regular stack emission monitoring, as well as conducting regular safety monitoring and audit. With the implementation of the recommended preventive measures and an effective emergency response plan for the IWMF, the health impacts associated with any potential accidental events could be minimized if not avoided.
15.2.9 Landscape and Visual Impact
15.2.9.1 During both the construction and operation phases, the impact to the landscape resources and landscape character areas would be “insubstantial”, except the Island Landscape (LCA1) which is rated as “moderate” and Seawater (LR3 & LCA2) which are rated as “substantial” before mitigation.
15.2.9.2
To avoid direct impact to the valuable landscape
resources of SKC, such as the natural shoreline (LR2), the reclamation area is
designed not be connected to SKC. The coast of
15.2.9.3 For LR3, since the seawater will be permanently replaced by the reclamation area, this portion of landscape resource is lost and cannot be recovered or mitigated. However, the quantity of loss of the seawater as landscape resource is relatively small in comparison to the large extent of the adjacent seawater landscape within and outside the study area. Together with other measures such as efficient site layout and use of cellular cofferdam for the construction of breakwater and the artificial island, the area occupied by the proposed works is reduced to practical minimum so that the impact to LR3 would be as small as possible.
15.2.9.4 For LCA2, apart from minimizing the landscape impact as mentioned above, extensive landscape areas and greening will be provided as a mitigation measure to improve the naturalness of the project site. The provision of new landscape elements will transform the existing landscape character.
15.2.9.5
Currently, the proposed projects in the vicinity
of the artificial island near SKC include the sewerage works in South Lantau
and the replacement of the existing submarine water main between Northern
Channel of Cheung Chau and
15.2.9.6 During the construction phase, the visual impact to most of the visual sensitive receivers would be “moderate / substantial”, and the visual impact to the sea travellers (VSR4) would be “substantial”. After the implementation of mitigation measures, the residual impact to the VSR4 would become “moderate / substantial” during construction while most of the other VSRs become “slight / moderate” or “moderate”.
15.2.9.7 During the operation phase, the visual impact to most of the visual sensitive receivers would be “moderate / substantial” or “moderate”, and the visual impact to the sea travellers (VSR4 & VSR12) would be “substantial” and “moderate / substantial” respectively. As these VSRs are transient in nature, the proposed works would unlikely create a prolonged visual impact to these VSRs.
15.2.9.8 Regarding the visual impacts induced by the reclamation and construction of facilities, mitigation measures are proposed including aesthetic design with a view to enhance the aesthetic quality and to blend in the proposed works into the natural surrounding, at the same time reducing the visual mass of the structure. This is achieved by rooftop and vertical greening along the building façade, use of natural materials with recessive colour, provision of sky gardens between the stacks, provision of observation deck to diminish the feeling of chimney, etc.
15.2.9.9
To maximize visual compatibility between the
existing natural shoreline of SKC and the IWMF, mitigation measure to adopt
natural rocks with similar colour as rocky
15.2.9.10 After the implementation of the proposed mitigation measures, the residual impact to some of the visual sensitive receivers would be reduced to “slight / moderate”, and the residual impact to the sea travellers (VSR4 & VSR12) would become “moderate / substantial” and “moderate” in day 1 of operation and “moderate” and “slight / moderate” respectively in year 10 of operation. The residual impact to some middle / long distance VSRs such as Cheung Sha (VSR5), Pui O Beach (VSR8) and Tong Fuk Beach (VSR11) would remain “moderate” in year 10 of operation due to the fact that some of the mitigation measures such as rooftop and vertical greening would not easily be appreciated from a distance.
15.2.9.11
The two proposed projects in the vicinity of the
artificial island near SKC, including the sewerage works in South Lantau and
the replacement of the existing submarine water main between Northern Channel
of Cheung Chau and
15.2.9.12
In conclusion, the potential landscape and
visual impacts can be reduced by implementing the proposed mitigation measures
during construction and operation phases. With reference to criteria defined in
Annex 10 of the EIAO TM, the overall residual impacts are considered as
“marginally acceptable with mitigation measures” after implementing the
mitigation measures, that is to say “there would be some adverse effects, but
these can be eliminated, reduced or offset by specific measures”.
15.2.10 Impact on Cultural Heritage
15.2.10.1 Based on the results of the desktop review and survey, no archaeological site was identified within the study area. No adverse archaeological impact is expected.
15.2.10.2 Geophysical surveys were conducted to examine the marine archaeological potential in the proposed reclamation area, breakwater and cable corridor for the IWMF. A total of 12 unidentified objects were spotted within the geophysical survey area. Seven out of twelve unidentified objects would be affected by the proposed works. A diver inspection was carried out, trying to locate the unidentified objects and establish their archaeological potential. A detailed search was conducted, but nothing was located. The results of the geophysical survey and diver inspection indicate there are no archaeological resources within the proposed reclamation area, and therefore no adverse marine archaeological impact is anticipated due to the proposed reclamation.
15.2.10.3 One grade 3 historic building (Courtyard Complex on the Shek Kwu Chau Treatment and Rehabilitation Centre of the Society for Aid and Rehabilitation of Drug Abusers) and four other built heritage structures with no grading are identified within the study area. However, due to large separation between the built heritages and the IWMF, no adverse impacts during the construction and operation phases are anticipated.
15.2.11 Summary of the Measures Taken for the Minimization of Environmental Impacts
15.2.11.1 The various chapters and appendices of this EIA report have presented the measures to minimize pollution in the planning, design, construction and operation stages. The key measures to minimize pollution are summarized below for easy reference and they are not exhaustive. For details, please refer to the relevant chapters and appendices as appropriate.
Adoption of Modern Incineration Technologies
15.2.11.2 The IWMF will employ modern incineration technologies including advanced process controls to optimize the combustion process and to achieve complete combustion of the MSW, proper breakdown of hazardous organic substances (e.g. volatile organics, dioxins) and pathogens (e.g. fungi, bacteria and viruses) in the MSW and prevent formation of new pollutants. The flue gases will be maintained at a temperature of over 850oC in the presence of a surplus of oxygen for adequate residence time (at least 2 seconds) and with high turbulence for better mixing in the combustion chamber. This is the so-called 3T incineration technology being adopted in modern moving grate incinerators. Coupled with advanced gas cleaning and pollution abatement equipment such as fabric filters, scrubbers and activated carbon powder injection system which effectively control the release of pollutants, the IWMF will meet the stringent emission limits stipulated by the European Commission for waste incineration. In addition, the IWMF will be installed with advanced air pollution control system namely selective catalytic reduction (SCR) for nitrogen oxides (NOx) removal. With the adoption of the SCR process, the daily average emission limit of NOx is lowered to 100 mg/m3, which is a 50% reduction when compared with the European Union (EU) standard.
Use of Cooling System
15.2.11.3 The heat energy of the air getting out from the furnace is transmitted to water, converting the water to high pressure steam. The high pressure steam is used to rotate a steam turbine and generate electricity. After the electricity generation process, the high pressure steam becomes low pressure steam, which is further cool down by a cooling system. Alternative cooling systems, including water-cooled condenser and air-cooled condenser, were considered. A water-cooled condenser involves exchange of the heat of the low pressure steam to water, which is then discharged to the nearby water body. An air-cooled condenser involves exchange of the heat of the low pressure steam to air, which is then discharged to the atmosphere. To minimize the potential impact to the nearby water bodies due to discharge of cooling water, air-cooled condenser was adopted in the IWMF. Another advantage of air-cooled condenser is water consumption will be greatly reduced.
Layout Arrangement
15.2.11.4 With a view to minimize the land use and the associated environmental impacts the layout for the IWMF is considered appropriate taking into consideration the functional need for operation of the IWMF, reasonable flexibility in design for future DBO contractor and allowance of suitable size of land for provision of visitors and community facilities. Based on the proposed layouts, the footprint requirement for treating per tonnage of MSW daily is approximately 38m2 at the artificial island near SKC. The area for breakwater at the artificial island near SKC was excluded in this unit footprint calculation. A larger footprint requirement at the artificial island near SKC is due to the additional land required for the berth area.
15.2.11.5
The unit footprint requirement of the IWMF is
comparable with other overseas incineration plants, including Afval Energie
Bedrijf (AEB) Incineration Plant with design capacity of 4,000 tpd in
Netherland and Tokyo Edogawa Incineration Plant with design capacity of 600 tpd
in
Construction Methods
15.2.11.6 Sloping seawall was originally proposed to be used at the artificial island near SKC. The width of the sloping seawall at the seabed level would be about 100m. The construction of the seawall involves dredging of a trapezoid trench to a width of 140m, and depth of 10m along the proposed location of the seawall at the seabed, filling of the trench with sand up to 2.5m below the seabed level and formation of the seawall above the sand fill by rock fill. The site area and dredging volume for the construction of the seawall is substantial. To minimize dredging and filling activities and the associated environmental impacts, cellular cofferdam and circular cell breakwater instead of sloping seawall were adopted for the construction of the seawalls and breakwaters, respectively.
15.2.11.7 Mitigation measure requirements specified for other environmental aspects are summarized below.
Measures for Air Quality
· Implementation of mitigation measures stated in the Air Pollution Control (Construction Dust) Regulation to minimize dust impacts during construction phase
· Installation of advanced air pollution control system, including SCR for NOx removal and activated carbon for dioxins removal and continuous emissions monitoring system
· 150m is selected as the stack height for the IWMF to further alleviate the potential air quality impacts at critical air sensitive receivers (ASRs) due to adverse terrain and building wake effects
· All odorous gases from the wastewater treatment plant, the waste reception halls and the waste storage areas would be fully enclosed and the odorous air in this facility would be extracted and used as combustion air for incineration to remove the odorous compounds
· Mechanical plant would be equipped with deodorizing system of 95% odour removal efficiency.
· The IWMF facilities would be operated under negative pressure to prevent odour leaking to the outdoor environment
Measures for Noise
· Good site practices to limit noise emissions at source and use of quiet plant and working methods, whenever practicable
· Provision of noise control treatment at the source during the design stage and implementing the same during operation phase for fixed plant noise
Measures for Water Quality
· Implementation of the recommended mitigation measures and site practices outlined in ProPECC PN 1/94 (Practice Note for Professional Persons on Construction Site Drainage) to minimize construction phase impacts
· Provision of on-site wastewater treatment plant. The treated effluent from the wastewater treatment plant will be reused in the incineration plant and mechanical treatment plant or for washdown and landscape irrigation within the IWMF site.
· A “net zero discharge” scheme will be adopted during the operation of the IWMF
· Reclamation and Construction of Breakwaters
Ø The proposed dredging and reclamation will be commenced in phases. The breakwaters and seawalls will be constructed using cofferdam method and the reclamation will be started within the enclosed breakwaters after the completion of the breakwater. Silt curtain will be used to surround the circular cell during the filling of the cell to prevent the loss of fine in the filling material.
Ø Water trapped inside the cofferdam, if any, will be pumped out for treatment before discharge
Ø The maximum production rate for dredging for the anti-scouring protection layer shall not exceed 380 m3 per day. It is recommended to employ closed grab with small capacity of 2 m3 to control the dredging rate. No dredging works will be carried out within 100 m from the nearest coral community.
Ø Any gap that may need to be provided for marine access will be located at the middle of the North Western seawall, away from the identified coral communities and will be shielded by silt curtains systems to control sediment plume dispersion.
Ø The silt curtain system at marine access opening will be closed as soon as the barges passes through the marine access opening in order to minimize the period of curtain opening. Filling will only be carried out behind the silt curtain when the silt curtain is completely closed.
Ø To enhance the effectiveness of the silt curtain at the marine access, the northern breakwater will be built before the commencement of the reclamation to reduce the current velocity towards the marine access opening
Ø The silt curtain system at marine access opening will be regularly checked and maintained to ensure proper functioning
Ø Where public fill is proposed for filling below +2.5mPD, the fine content in the public fill will be controlled to 25% which is in line with the CEDD’s General Specification
Ø The filling for reclamation will be carried out behind the seawall. The filling material will only consist of public fill, rock and sand. The production rate for each composition at each filling area will be controlled to minimize the elevation in SS during reclamation filling.
Ø For dredging for anti-scouring protection layer, the production rate will be controlled to minimize the elevation in SS during dredging operation
Ø No dredging will be carried out within 100 m to the nearest non-translocatable coral community
Ø Daily site audit including full-time on-site monitoring by the ET is recommended during the dredging for anti-scouring protection layer for checking the compliance with the permitted number of grab
Ø Closed grab dredger will be used to minimize the loss of sediment during the raising of the loaded grabs through the water column
Ø Frame-type silt curtains will be deployed around the dredging operations
Ø Floating-type silt curtains will be used to surround the circular cell during the sheetpiling work
Ø The descent speed of grabs will be controlled to minimize the seabed impact speed
Ø Barges will be loaded carefully to avoid splashing of material
Ø All barges used for the transport of dredged materials will be fitted with tight bottom seals in order to prevent leakage of material during loading and transport
Ø No concurrence works between laying of submarine cables and dredging/reclamation works within the same location will be allowed. For works close to each other, the construction program will be arranged so that the dredging/reclamation works within area bounded by the breakwaters and the laying of cables will not operate within a distance of 80m from each other to avoid any accumulative impact on the environment (in case if such tight schedule is necessary).
Ø All barges should only be filled to a level which would not allow the material to spill over during loading and transport to the disposal site and that adequate freeboard will be maintained to ensure that the decks would not washed by wave action
· Operational Phase Discharges
Ø A pipeline drainage system will serve the project site collecting surface runoff from paved areas, roof, etc. Sustainable drainage principle will be adopted in the drainage system design to minimize peak surface runoff, maximize permeable surface and maximize beneficial use of rainwater.
Ø Oil interceptors will be provided in the drainage system of any potentially contaminated areas (such as truck parking area and maintenance workshop) and regularly cleaned to prevent the release of oil products into the storm water drainage system in case of accidental spillages. Accidental spillage will be cleaned up as soon as practicable and all waste oils and fuels will be collected and handled in compliance with the Waste Disposal Ordinance.
Measures for Waste Management
· To avoid offsite disposal of C&D materials and to implement the recommended mitigation measures and site practices outlined in ETWB TCW No. 19/2005, 31/2004 & 34/2002 on construction waste management
· The end product from the incineration process of the IWMF will be disposed of at a landfill after checking for compliance with the proposed incineration residue pollution control limits. Pre-treatment of fly ash and air pollution control residues will be undertaken prior to disposal at landfill.
Measures for Ecology
· Measures to avoid direct loss of intertidal habitat
Ø
The site boundary has been proposed to avoid
direct contact with the intertidal natural rocky
· Measures to minimise loss of coastal subtidal habitat
Ø Extensive coral colonies were recorded at the coastal hard bottom habitat at Shek Kwu Chau. To avoid and minimise the extensive direct impact on the coral colonies, the proposed reclamation area has been moved further offshore to minimise loss of subtial habitat near shore.
· Measures to avoid loss of plant species of conservation importance
Ø Landing portal construction works would not cause direct lost to the recorded individual of protected plant species, Aquilaria sinensis, at the coastal shrubland habitat at Cheung Sha. As a precautionary measure, the plant will be tagged with eye-catching tape and fenced off prior to works, in order to avoid any damage by workers.
· Measures to minimise disturbance on Finless Porpoise
Ø Minimisation of Habitat Loss for Finless Porpoise
o
Substantial revision has been made on the layout
plan and form of the breakwater, in order to minimise the potential loss of
important habitat for Finless Porpoise. The revision has greatly reduced the
size of the embayment area, as well as the Project footprint. As a result, the
size of habitat loss for Finless Porpoise has reduced from the original ~
Ø Avoidance of peak season for finless porpoise occurrence
o To minimise potential acoustic disturbance from construction activities on Finless Porpoise, construction works that may produce underwater acoustic disturbance will be scheduled outside the months with peak Finless Porpoise occurrence (December to May)
o Such works will be restricted within June to November. This approach would not only avoid the peak season for Finless Porpoise occurrence, the magnitude of impacts arise from acoustic disturbance will also be minimised.
o Submarine cable installation works are also recommended to be scheduled within June to November, when sightings of Finless Porpoise is scarce in the area of the proposed alignment of the submarine cable.
Ø Opt for quieter construction methods and plants
o Considering the sensitivity of marine mammals to underwater acoustic disturbance, instead of the previously proposed conventional breakwater and reclamation peripheral structure, which requires noisy piling works, the current circular cells structure for breakwater and reclamation peripheral structure is proposed. A quieter sheet piling method using vibratory hammer or hydraulic impact hammer will be adopted for the installation of circular cells for cellular cofferdam and northern breakwater during Phase 1, and southern breakwater Phase 3.
o Non-percussive bore piling method will be adopted for the installation of tubular piles for the berth construction during Phase 3.
Ø Monitored exclusion zones
o
During the installation/re-installation/relocation
process of floating type silt curtains, in order to avoid the accidental
entrance and entrapment of marine mammals within the silt curtains, a monitored
exclusion zone of
o The experienced marine mammal observer should be well trained to detect marine mammals. Binoculars will be used to search the exclusion zone from an elevated platform with unobstructed visibility. The observer should also be independent from the project proponent and has the power to call-off construction activities.
o In addition, as marine mammals cannot be effectively monitored within the proposed monitored exclusion zone at night, or during adverse weather conditions (i.e. Beaufort 5 or above, visibility of 300 meters or below), marine works will be avoided under weather conditions with low visibility.
Ø Marine mammal watching plan
o Upon the completion of the installation/re-installation/relocation of floating type silt curtain, all marine works would be conducted within a fully enclosed environment within the silt curtain, hence exclusion zone monitoring would no longer be required. Subsequently, a marine mammal watching plan should be implemented. The plan will include regular inspection of silt curtains, and visual inspection of the waters surrounded by the curtains. Special attention will be paid to Phase 2 (reclamation) where the floating type still curtain would be opened occasionally for vessel access, leaving a temporary 50 m opening. An action plan will be devised to cope with any unpredicted incidents such as the case when marine mammals are found within the waters surrounded by the silt curtains.
Ø Small openings at silt curtains
o The openings for vessel access at the silt curtains will be as small as possible to minimise the risk of accidental entrance.
Ø Adoption of regular travel route
o During construction and operation, captains of all vessels will adopt regular travel route, in order to minimize the chance of vessel collision with marine mammals, which may otherwise result in damage to health or mortality. The regular travel route will avoid areas with high sighting density of Finless Porpoise as much as possible.
Ø Vessel speed limit
o The frequent vessel traffic in the vicinity of works area may increase the chance of mammal mammals being killed or seriously injured by vessel collision. A speed limit of ten knots will be strictly enforced within areas with high density of Finless Porpoise.
o Passive acoustic monitoring and land-based theodolite monitoring surveys should be adopted to verify the predicted impacts and effectiveness of the proposed mitigation measures.
Ø Training of Staff
o Staff, including captains of vessels, should be aware of the guidelines for safe vessel operations in the presence of cetaceans during construction and operation phases. Adequate trainings will be provided.
· Measures to minimise impact on corals
Ø Coral translocation
o Coral communities within and in proximity to the proposed dredging sites would be disturbed by the Project due to the dredging operations. In order to minimise direct loss of coral communities, translocation of corals that are attached to movable rocks with diameter less than 50 cm are recommended. In order to avoid disturbance to corals during the spawning period, the spawning season of corals (June to August) will be avoided; and that translocation should be carried out during the winter season (November- March).
o
The REA survey results suggest that the 198
directly affected coral colonies were attached to movable rocks (less than
o Prior to coral translocation, a more detailed baseline survey, including a coral mapping survey, is recommended to further confirm the exact number and location of coral colonies within the potentially affected area. A more detailed coral translocation plan, including selection of suitable recipient site, plan for coral translocation, and event / action plan for coral monitoring will be submitted upon approval of this Project, prior to commencement of construction works. Advice from relevant governmental departments (i.e. AFCD) and professionals would be sought after, in order to identify a desirable location for the relocation of coral communities. Post-translocation monitoring on the translocated corals will also be considered.
Ø Coral monitoring programme
o A coral monitoring programme is recommended to assess any adverse and unacceptable impacts to the coral communities at the coasts of Shek Kwu Chau during construction of the Project.
Ø Phasing of Works
o To minimize environmental impacts, the proposed phasing of construction works has been carefully designed to reduce the amount of concurrent works, hence minimise SS elevation and the associated impacts on corals.
·
Specific measures to minimise disturbance on
breeding
Ø
Avoidance of noisy works during the breeding
season of
o To minimise potential noise disturbance from construction activities on WBSE, noisy construction works will be scheduled outside their breeding season (December to May) to minimise potential degradation in breeding ground quality and breeding activities, including:
- sheet piling works for construction of cofferdam surrounding the reclamation area (Phase 1);
- sheet piling works for construction of the shorter section of breakwater (Phase 1);
- sheet piling works for construction of the remaining section of breakwater (Phase 3); and
- bored piling works for berth area (Phase 3).
Ø Opt for quieter construction methods and plants
Ø
Restriction on vessel access near the nest of
o During construction and operation, in order to minimise disturbance on the existing WBSE nest, a pre-defined practical route to restrict vessel access near the nest will be adopted to keep vessels and boats as far away from the nest as possible.
Ø
o A WBSE monitoring programme is recommended to assess any adverse and unacceptable impacts to the breeding activities of WBSE during construction and operation of the Project. Monitoring surveys for WBSE would include pre-construction phase (twice per month for duration of three months during their breeding season - between December and May, immediately before the commencement of works), construction phase, and operation phase (two years after the completion of construction works).
o Surveys will be conducted twice per month during their breeding season (from December to May); and once per month outside breeding season (June to November).
Ø Education of staff
o Staff, including captains of all vessels during construction and operation phases, will be aware of the ecological importance of WBSE. Awareness will be raised among staff to minimise any intentional or unintentional disturbance to the nest.
Ø Minimisation of glare disturbance
o To minimise glare disturbance on WBSE, which may cause disorientation of birds by interfering with their magnetic compass, and disruption in behavioural patterns such as reproduction, fat storage and foraging pattern, any un-necessary outdoor lighting will be avoided, and in-ward and down-ward pointing of lights will be adopted.
· Opt for Quieter Construction Methods and Plants
Ø Quieter construction methods and plants will be used to minimise disturbance to the nearby terrestrial habitat and the associated wildlife.
· Measures to minimise impacts from artificial lighting
Ø Unnecessary lighting will be avoided, and shielding of lights will be provided to minimise disturbance from light pollution on fauna groups.
· Control of marine habitat quality during operation phase
Ø
Depending on the seabed condition of the
approach channel for marine vessels during operation phase of the IWMF,
maintenance dredging may be required to ensure safe access. In order to avoid degradation in water
quality due to elevation in SS and dispersion of sediment plume due to dredging
works, it is recommended that any future maintenance dredging works will not be
carried out within
· Compensation of loss of important habitat of Finless Porpoise
Ø
Designation of
o The Project Proponent has made a firm commitment to seek to designate a marine park of approximately 700 ha in the waters between Soko Islands and Shek Kwu Chau, in accordance with the statutory process stipulated in the Marine Parks Ordinance, as a compensation measure for the habitat loss arising from the construction of the IWMF at the artificial island near SKC.
o The Project Proponent will seek to complete the designation by 2018 to tie in with the operation of the IWMF at the artificial island near SKC.
o A further study should be carried out to review relevant previous studies and collate available information on the ecological characters of the proposed area for marine park designation; and review available survey data for Finless Porpoise, water quality, fisheries, marine traffic and planned development projects in the vicinity. Based on the findings, ecological profiles of the proposed area for marine park designation should be established, and the extent and location of the proposed marine park be determined. The adequacy of enhancement measures should also be reviewed.
o In addition, a management plan for the proposed marine park will be proposed, covering information on the responsible departments for operation and management (O&M) of the marine park, as well as the O&M duties of each of the departments involved. Consultation with relevant government departments and stakeholders should be conducted under the study. The study will be submitted to Director of Environmental Protection (DEP) for approval before the commencement of construction works.
o The Project Proponent will provide assistance to AFCD during the process of the marine park designation. .
· Additional Enhancement or Precautionary Measures
Ø Deployment of Artificial Reefs
o Deployment of artificial reefs (ARs) is an enhancement measure for the marine habitats. ARs are proposed to be deployed within the proposed marine park under this Project. The exact location, dimension and type of ARs to be deployed are to be further investigated along with the further study of the proposed marine park under this Project. The proposed ARs would be deployed at the same time as the complete designation of marine park.
Ø
Release of Fish Fry at Artificial Reefs and
o Release of fish fry at the proposed ARs, as well as the proposed marine park under this study, will enhance the fish resources in the nearby waters, and subsequently food sources for Finless Porpoise. The proposed ARs with various micro-habitats would have the potential to provide shelter and nursery ground for the released fish fry. The frequency and quantity of fry to be released will be agreed by AFCD.
Measures for Fisheries
· Measure to minimise loss of and disturbance on fisheries resources
Ø Alteration to the phasing of works, construction method, and layout plan of the IWMF at the artificial island near SKC has been made. The total fishing ground to be permanently lost due to the project has been significantly reduced from ~50 ha to ~31 ha. By adopting the current circular cells instead of the conventional seawall construction method, SS elevation would be greatly reduced, minimising adverse impact on the health of fisheries resources.
· Measure to minimise impingement and entrainment
Ø Provision of a screen at the water intake point for desalination plant would be essential to minimise the risk of impingement and entrainment of fisheries resources (including fish, larvae and egg) through the intake point.
· Measures to control water quality
Ø No wastewater effluent, anti-fouling agent, heavy metals and other contaminants would be released during operation phase of the Project.
Ø Mitigation measures recommended in the water quality impact assessment during construction and operation would serve to protect fisheries resources from indirect impacts resulted from the Project
· Additional Enhancement / Precautionary Measures
Ø Artificial Reefs (ARs) are proposed to be deployed within the proposed marine park under this Project as an enhancement measure for the marine habitats. This enhancement feature would bring positive impacts to the previously identified important spawning and nursery ground for fisheries resources.
Ø Release of Fish Fry at Artificial Reefs
o Release of fish fry has been proposed under this Project. The proposed deployment of ARs within the proposed marine park would provide shelter and nursery ground for the released fish fry. The frequency and quantity of fry to be released should be agreed by AFCD.
Measures for Health Impact
· The air quality measures described above will also minimize the potential health risk associated with air emissions from the IWMF
Measures for Landscape and Visual Impact
· All bare soil surface will be grass-hydroseeded
· Landscape design
Ø Early planting using fast grow trees and tall shrubs at strategic locations within site as buffer to block view corridors to the site from the VSRs, and to locally screen haul roads, excavation works and site preparation works.
Ø Use of tree species of dense tree crown to serve as visual barrier.
Ø Hard and soft landscape treatment (e.g. trees and shrubs) of open areas within development to provide a background for the outdoor containers from open view, shade and shelter, and a green appearance from surrounding viewpoints.
Ø Planting strip along the periphery of the project site.
Ø Selected tree species suitable for the coastal condition.
· Adoption of Natural Features of the Existing Shoreline
Ø Use of boulders in different sizes and with the similar textures of the existing rocky shores for the construction of breakwater and artificial shoreline in order to blend into the existing natural shoreline.
Ø Use of cellular cofferdam together with the natural boulders to form a curvature shoreline for the reclamation area to echo with the natural shoreline of SKC.
· Greening design (rooftop & vertical greening)
Ø Implementation of rooftop and vertical greening (vertical building envelope) along the periphery of each building block to increase the amenity value of the work, moderate temperature extremes and enhance building energy performance. The greening appearance of the building shall enhance its visual harmony with the natural surroundings as well as reduce the apparent visual mass of the structure.
Ø Sufficient space between concrete enclosure and stack to minimize heat transfer.
Ø Introduction of landscape decks at the stack to further enhance the overall natural and green concept unique for this site.
· Visual mitigation and aesthetic design
Ø Use of natural materials with recessive color to minimize the bulkiness of the building.
Ø Adoption of innovative aesthetic design to the chimney to minimize or visually mitigate the massing of the chimney so as to reduce its visual impact to the surroundings.
Ø Color of the chimney in a gradual changing manner to match with the color of the sky.
Ø Provision of observation deck for public enjoyment at the top of the chimney to diminish the feeling of chimney.
Ø Provision of sky gardens between the two stacks to allow additional greening for enhancing the aesthetic quality. Maintenance access (elevator and staircase) from the ground floor to the sky gardens will be provided to allow maintenance of the sky gardens.
Ø Integration of the visitor’s walkway with different material façade design of incinerator plant to enhance the aesthetic quality.
· Control of the security floodlight for construction areas at night to avoid excessive glare to the surrounding receiver.
· Optimization of the construction sequence and construction programme to minimize the duration of impact.
· Storage of the backfilling materials for site formation & construction materials / wastes on site at a maximum height of 2m, covered with an impermeable material of visually un-obtrusive material (in earth tone).
· Reduction of the number of construction traffic at the site to practical minimum.
· Planting maintenance
Ø Proper planting maintenance and replacement of defective plant species on the new planting areas to enhance aesthetic and landscape quality will be provided
· Control of light
Ø The numbers of lights and their intensity will be controlled to a level good enough to meet the safety requirements at night but not excessive
· Control of operation time
Ø The frequency of waste transportation will be minimized to practical minimum (e.g. limit the reception of MSW from 8 am to 8 pm)
15.3
Impact Summary for IWMF at both
Tsang Tsui Ash Lagoon Site and the
15.3.1.1 It is expected that the co-exist scenario with a 3,000 tpd IWMF at each of the sites would likely give rise to potential cumulative air quality and health impacts associated with aerial emissions from the two IWMFs during the operation phase. Other potential impacts arising from construction and operation of the two IWMFs would be localized at the respective sites and significant changes in the level of impacts specifically associated with the co-existence of the two IWMFs are not anticipated.
15.3.1.2 This EIA Report has provided an assessment of the potential air quality and health impacts associated with the operation of the two IWMFs at both the TTAL site and the artificial island near SKC, with the consideration of the potential cumulative impact from other concurrent projects in the vicinity of the TTAL site and the artificial island near SKC. Specific mitigation measures required for the Project, as well as an environmental monitoring and auditing programme, have been developed. A summary of the operation phase air quality and health impacts associated with this co-exist scenario is presented below.
15.3.2.1
Advanced air pollution control system, including
SCR for NOx removal and activated carbon for dioxins removal and continuous
emissions monitoring system will be installed for the IWMF to ensure that the
emissions from the IWMF stacks will meet the proposed target emission limits
that is more stringent than those stipulated in
15.3.2.2
Cumulative air quality impact assessment has
been undertaken for the Project for the co-exist scenario. The cumulative air quality impact assessment
has taken into account the emissions from both regional and local sources,
including the emissions within the Pearl River Delta Economic Zone and major
local air pollution sources in
15.3.3.1 The cancer risk arising from exposure to compounds of potential concern (COPCs) associated with the emissions of IWMFs under the co-exist scenario is evaluated in this EIA Study. The highest incremental (excess) cancer risk arising from the IWMF is predicted to be 4.20x10-6 which is within the screening level of 1x10-5 adopted by USEPA and it is considered that the Project would not present an unacceptable risk and no further analysis is necessary. The highest predicted total Hazard Index (HI) at all receptors are well below 0.25, which is an initial exposure benchmark derived from a conservative approach by the USEPA. Cumulative acute non-carcinogenic health impact of the IWMF imposed to the worst impacted human receptors were assessed and compared with local and overseas guideline levels. It was concluded that the levels of non-carcinogenic chemicals were found to be insignificant when compared to the adopted/derived reference levels. For the classical COPCs of the HKAQO, while it is not possible to rule out adverse health effects from the IWMF with complete certainty, the impact on health from small additional air pollutants is likely to be very small and unlikely to be quantifiable.
15.4 Key Environmental Outcomes and Summary of Environmental Performance Comparison
15.4.1.1 The major sensitive areas within the study area include different type of residential development from village houses to high-rise residential buildings, commercial buildings, industrial premises, recreational areas and place of public worship have been identified. A summary of the key environmental outcomes arising from this EIA study, environmental benefits of the environmental protection measures and comparing the environmental performance of the IWMF at TTAL site and the IWMF at the artificial island near SKC are presented in Table 15.1 below.
Table 15.1 Summary of Key
Environmental Outcomes / Benefits and Environmental Performance Comparison
|
Issue |
Environmental Outcome / Benefits for the IWMF at the TTAL site |
Environmental Outcome / Benefits for the IWMF at the artificial island near SKC |
|
Major environmental benefits of the Project and key environmental problems avoided |
Compared with other major cities
in the world, Hong Kong has uniquely relied mainly on landfills
for the disposal of its municipal solid waste (MSW). Over the past years, the
quantity of MSW generated has been on an increasing trend due to population
growth. In 2008, approximately 18,000 tonnes of MSW were generated per day,
which were about 30% more in comparison to the MSW generated over 10 years
ago. Consequently the three strategic landfills in If an alternative disposal method for MSW is not sought (i.e. scenario without the Project), MSW would continue to be disposed of at landfills, placing burden on the limited landfill capacity in Hong Kong and shortening the life of the landfills in a rapid rate. The capacity of the landfills will need to be further extended and more land will be occupied for MSW disposal. With the proposed IWMF, the amount of MSW to be disposed of at landfills will substantially decrease as the volume of waste generated after the thermal treatment process would only be about 10% of the original volume. The existing landfills can serve for a longer period of time. Besides, the production of greenhouse gases due to landfilling of MSW will be reduced. |
Compared with other major cities
in the world, If an alternative disposal method for MSW is not sought (i.e. scenario without the Project), MSW would continue to be disposed of at landfills, placing burden on the limited landfill capacity in Hong Kong and shortening the life of the landfills in a rapid rate. The capacity of the landfills will need to be further extended and more land will be occupied for MSW disposal. With the proposed IWMF, the amount of MSW to be disposed of at landfills will substantially decrease as the volume of waste generated after the thermal treatment process would only be about 10% of the original volume. The existing landfills can serve for a longer period of time. Besides, the production of greenhouse gases due to landfilling of MSW will be reduced. |
|
Environmentally friendly designs recommended |
A review of the latest development of various MSW treatment technologies was conducted. The results of the review reconfirmed the recommendations from the Advisory Group (AG) on Waste Management Facilities that incineration technology could still play a core role in the IWMF Phase 1 for MSW treatment. An evaluation of three shortlisted thermal treatment technologies, including moving grate incineration, fluidized-bed incineration and gasification technologies, were carried out. The results indicated that moving grate incineration is more suitable to be adopted as a core technology of the IWMF Phase 1, taking into consideration the following advantages: · Less volume of flue gas produced from the furnaces and less the amount of the air pollutant generated comparing with fluidized-bed incineration · Proven technology with the capacity to treat large amount of MSW · Least scale-up risks · Long track record of operation · High capability to tolerate the fluctuation of MSW characteristics with robust/ forgiving nature · Less land requirement for the treatment units · Less operation complexity · Less capital and operating costs |
A review of the latest development of various MSW treatment technologies was conducted. The results of the review reconfirmed the recommendations from the Advisory Group (AG) on Waste Management Facilities that incineration technology could still play a core role in the IWMF Phase 1 for MSW treatment. An evaluation of three shortlisted thermal treatment technologies, including moving grate incineration, fluidized-bed incineration and gasification technologies, were carried out. The results indicated that moving grate incineration is more suitable to be adopted as a core technology of the IWMF Phase 1, taking into consideration the following advantages: · Less volume of flue gas produced from the furnaces and less the amount of the air pollutant generated comparing with fluidized-bed incineration · Proven technology with the capacity to treat large amount of MSW · Least scale-up risks · Long track record of operation · High capability to tolerate the fluctuation of MSW characteristics with robust/ forgiving nature · Less land requirement for the treatment units · Less operation complexity · Less capital and operating costs |
|
Population and Environmentally Sensitive Areas Protected |
The major sensitive areas within the
study area include different type of residential development from village
houses to high-rise residential buildings, commercial buildings, industrial
premises, recreational areas and place of public worship located within north-west
|
The major sensitive areas within the
study area include different type of residential development from village
houses to high-rise residential buildings, commercial buildings, industrial
premises, recreational areas and place of public worship located within Shek Kwu Chau, |
|
Major Emission Sources in the vicinity of the Project Site |
Major emission sources include Ecopark, Sludge Treatment Facilities, Green Island Cement Facilities, Existing WENT Landfill and its Extensions, Shiu Wing Steel Mill, Black Point and Castle Peak Power Stations |
No major emission sources in the vicinity of Shek Kwu Chau. |
|
Air Quality |
Environmental benefits of environmental protection measures recommended: Those ASRs
located near the construction sites are protected through implementation of practicable
dust suppression measures. Air pollution
control and stack monitoring system will be installed for the IWMF to ensure
that the emissions from the IWMF stacks will meet the proposed target emission
limits that is more stringent than those stipulated in No unacceptable
residual impacts from the cumulative impacts of the IWMF emissions and other
existing emissions are anticipated at the ASRs. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Existing ASRs
& planned developments, including residential, commercial and
recreational areas located within north-west |
Environmental benefits of environmental protection measures recommended: Those ASRs
located near the construction sites are protected through implementation of practicable
dust suppression measures. Air pollution
control and stack monitoring system will be installed for the IWMF to ensure
that the emissions from the IWMF stacks will meet the proposed target
emission limits that is more stringent than those stipulated in No unacceptable
residual impacts from the cumulative impacts of the IWMF emissions and other
existing emissions are anticipated at the ASRs. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Existing ASRs
& planned developments, including residential, commercial and
recreational areas located within Shek Kwu Chau, |
|
Noise Impact |
Environmental benefits of environmental protection measures recommended: The residual
noise exceedances at the representative NSRs are due to the existing off-site
traffic flow. The overall road noise
contribution due to the off-site traffic generated from the operation of the
proposed IWMF would be less than 1 dB(A).
No adverse noise impacts arising from the operation of IWMF are
predicted at any of the representative NSRs. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Existing NSRs located in close proximity
along |
Environmental benefits of environmental protection measures recommended: The predicted unmitigated noise levels complied with the noise standards at all NSRs. Silencer and acoustic treatment were proposed for the stack of the incinerator, ventilation systems and air-cooled chillers within the IWMF, no adverse residual operation noise impact is anticipated. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Existing and planned NSRs within 300m of the project boundary. |
|
Water Impact |
Environmental benefits of environmental protection measures recommended: Mitigation measures and site practices
outlined in ProPECC PN 1/94 are recommended to minimize the potential water
quality impact from construction site runoff and drainage, wastewater
generated from general construction activities and sewerage from the workforce. During the
operation phase of the Project, wastewater (including human sewage) generated
from the proposed incineration plant and mechanical treatment plant will be
treated in an on-site wastewater treatment plant. All treated effluent will
be reused on-site. A
“net zero discharge” scheme will be adopted during the operation of the IWMF
Phase 1. Compensation
areas included: The recommended
water quality mitigation measures would minimize the water quality impact to
the receiving water. Population
and environmental sensitive receivers protected: The receiving
marine water in the Deep Bay WCZ. |
Environmental benefits of environmental protection measures recommended: Mitigation
measures (including construction of breakwaters using cofferdam, reclamation
after the reclamation site is enclosed with completed seawall, the use of
closed grab for dredging, deployment of frame-type silt curtain and control
of dredging rate) are proposed to ensure that no unacceptable water quality
impact would be resulted from the marine works for construction of the
breakwaters and reclamation. During the
operation phase of the Project, wastewater (including human sewage) generated
from the proposed incineration plant and mechanical treatment plant will be
treated in an on-site wastewater treatment plant. All treated effluent will
be reused on-site. There
would be no wastewater effluent discharged to the marine waters of The incineration waste would be treated and be stabilized before marine transportation to the WENT landfill, and during transportation, the incineration would be stored in storage silo and covered container, to minimized any risk concerning accidental spillage. Compensation
areas included: The recommended
water quality mitigation measures would minimize the water quality impact to
the receiving water. Population
and environmental sensitive receivers protected: The receiving
marine water in the Southern WCZ, the water sensitive receivers in the
Southern WCZ including coral communities near the southwestern coast of SKC,
horseshoe crab at the northern coast of SKC, beaches at the southern shore of
the Lantau Island and the Cheung Sha Wan Fish Culture Zone |
|
Waste Management Implications |
Environmental benefits of environmental protection measures recommended: Implementation
of the proposed waste control and mitigation measures would avoid the
potential air, noise and water quality impacts associated with handling,
transportation and disposal of the identified wastes arising from the
construction phase of the Project. During operation
phase, the bottom ash, fly ash and air pollution control residues will be
disposed of at the landfill after checked for compliance with the proposed
incineration residue pollution control limits. Besides, with proper implementation of the
recommended practices and response procedures for contamination prevention,
the potential for land contamination due to the IWMF Phase I operation would
be minimal. No residual
waste impact arising from the operation of the Project is expected. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Air, noise and water quality sensitive receivers at or near the Project site, the waste transportation routes and the waste disposal site. |
Environmental benefits of environmental protection measures recommended: Small-scale
dredging for the construction of the proposed cofferdam would generate
approximately 27,300m3 of marine sediment. Based on the chemical screening, these
sediments are suitable for Type 1 – Open Sea Disposal. Mitigation measures for dredging,
transportation and disposal are recommended, and no adverse impact from
sediment dredging is anticipated. No construction
and excavation works will be required for the existing The amount of
fill required for the reclamation of the artificial island near SKC is
estimated to be about 2.4Mm3. The reclamation
of the artificial island near SKC will thus has a side benefit of utilizing the
C&D material stored in the fill banks to alleviate the current C&D
material disposal problem in With proper implementation
of the proposed waste control and mitigation measures, the handling,
transportation and disposal of the identified wastes arising from the
construction phase of the Project will not cause adverse dust, noise and
water quality impacts. During operation
phase, the bottom ash, fly ash and air pollution control residues will be
disposed of at the landfill after checked for compliance with the proposed
incineration residue pollution control limits. Besides, with proper implementation of the
recommended practices and response procedures for contamination prevention,
the potential for land contamination due to the IWMF Phase I operation would
be minimal. No residual waste impact arising from the operation of the
Project is expected. Should dredging
is not required for the reclamation area (subject to results from further
geotechnical ground investigation), the site would be susceptible to biogas
hazard. Gas monitoring and protective
measures are recommended to minimize the impact due to biogas generation. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Air, noise and
water quality sensitive receivers at or near the Project site, the waste
transportation routes and the waste disposal site. |
|
Ecological Impact |
Environmental benefits of environmental protection measures recommended: Direct
impact to breeding activities of Little Grebe could be avoided by undertaking
thorough site inspection in the Middle Lagoon by experienced ecologist before
the commencement of any construction activities. Careful
selection of location of seawater intake/saline water discharge would avoid
direct loss of gorgonian. Indirect
disturbance to wildlife in nearby habitat would be minimized through the
setup of hoarding, the use of quieter piling machinery and construction
plants, and screen planting in or around the project site and associated
access road. Water
quality control measures would be implemented to minimize indirect impact on
seafront and associated wildlife caused by water quality deterioration. Compensation areas included: Created habitats for Little Grebe in form of shallow pond(s) would
be provided in a less disturbed area within the project site. Population and environmental sensitive receivers protected: Vegetation, wildlife and their associated habitats at and in the vicinity of the project site. |
Environmental benefits of environmental protection measures recommended: Avoid ·
direct loss of intertidal
habitat at SKC ·
direct loss of plant
species of conservation importance at Cheung Sha ·
discharge of untreated
wastewater into the marine environment, which is the habitat of Finless
Porpoise and corals, via a zero discharge scheme Minimise ·
loss of coastal habitat ·
degradation in water
quality, hence marine habitat ·
loss of corals by
translocation of colonies that may be directly affected ·
disturbance on Finless
Porpoise, corals, and nest of White-bellied Sea Eagle ·
impacts on fauna from
noise disturbance and artificial lighting ·
impacts on fauna from
accidental spillage, sewage effluent, and construction runoff ·
risk from pest
introduction Compensation
areas included: ·
Compensate the 31 ha loss of
important habitat of Finless Porpoise by firm commitment from Project
Proponent to seek to designate a marine park of approximately 700 ha in
waters between Additional
enhancement or precautionary measures include: ·
Enhance marine habitat by
deployment of artificial reef within the proposed marine park under this
Project and release of fish fry. Population
and environmental sensitive receivers protected: Vegetation, wildlife and their associated habitats within and in the vicinity of the Project Site. |
|
Fisheries Impact |
Environmental benefits of environmental protection measures recommended: In view of the
localized and insignificant water quality change, fisheries impacts due to
construction site runoff and seawater intake/saline water discharge are
considered as minor and acceptable.
Water quality control measures such as use of effective site drainage
would minimize indirect impacts on fisheries resources due to change in water
quality. Compensation
areas included: Not required (no
significant adverse fisheries impact is anticipated). Population
and environmental sensitive receivers protected: Fisheries resources near the project site |
Environmental benefits of environmental protection measures recommended: Alteration to the phasing of works, construction method, and layout plan of the IWMF has been made. The total fishing ground to be permanently lost would be significantly reduced from ~50 ha to ~31 ha. By adopting cofferdam instead of the conventional seawall and breakwater construction method, SS elevation would be greatly reduced, minimising adverse impact on the health of fisheries resources. Provision of a screen at the water intake point for desalination plant would be essential to minimise the risk of impingement and entrainment of fisheries resources (including fish, larvae and egg) through the intake point. The recommended water quality control measures would protect fisheries resources from adverse indirect impact on fisheries resources result from the Project With the proper implementation of the recommended mitigation measures, potential impact on fisheries would be minimised. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Fisheries resources, including adult and juvenile fish, and fish egg. |
|
Landscape and Visual Impact |
Environmental benefits of environmental protection measures recommended: Implementation of
mitigation measures, such as advanced screening tree planting, existing trees
preservation, transplanting trees to adjacent locations, compensatory
landscape planting, landscape design, reuse existing boulders, light control,
construction traffic control, planting maintenance, etc. within
the site area; aesthetic and greening design of the proposed IWMF matching
with adjacent landscape setting of the site; and operation
of education center for the public, would enhance the compatibility of the
IWMF with the surrounding landscape setting, reduce the impacts to the visual
sensitive receivers (VSRs) and alleviate negative public perceptions of the
development. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Existing and future VSRs identified with the Zone of Visual Influence
of the Project. |
Environmental benefits of environmental protection measures recommended: Implementation of
mitigation measures, such as advanced screening tree planting, landscape
design, reuse existing boulders similar to SKC natural coastline, light
control, planting maintenance, etc. within the site area; aesthetic and
greening design of the proposed IWMF matching with adjacent landscape setting
of the site; and operation of education center for the
public, would enhance the compatibility of the IWMF with the surrounding
landscape setting, reduce the impacts to the visual sensitive receivers
(VSRs) and alleviate negative public perceptions of the development. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: Existing and future VSRs identified with the Zone of Visual Influence
of the Project. |
|
Human
Health Risk |
Environmental benefits of environmental protection measures recommended: The predicted health risk levels complied with the proposed criteria at all receptors. No adverse human health risk impact is expected. Besides, design measures for radon, such as a soil cover beneath the buildings before construction works and sufficient ventilation would reduce radon influx; regular maintenance for floor slabs and walls shall make radon reduction techniques more effective and cost-efficient. Compensation areas included: N/A Population
and environmental sensitive receivers protected: Construction and operation staff of the IWMF Project as well as the sensitive receivers in close proximity of the Project site. |
Environmental benefits of environmental protection measures recommended: The predicted health risk levels complied with the proposed criteria at all receptors. No adverse human health risk impact is expected. Compensation areas included: N/A Population
and environmental sensitive receivers protected: Operation staff of the IWMF Project as well as the sensitive receivers in close proximity of the Project site. |
|
Impact
on Cultural Heritage |
Environmental benefits of environmental protection measures recommended: A desktop study
and field survey have been conducted and revealed no adverse impact to the
Tsang Tsui Archaeological Site, Compensation
areas included: N/A Population
and environmental sensitive receivers protected: N/A |
Environmental benefits of environmental protection measures recommended: One grade 3 historic building (Courtyard Complex on the Shek Kwu Chau Treatment and Rehabilitation Centre of the Society for Aid and Rehabilitation of Drug Abusers) and four other built heritage structures with no grading are identified within the study area. However, due to large separation between the built heritages and the IWMF, no adverse impact to the built heritage structures is identified. Regarding the marine archaeological
potential in the proposed reclamation area to the southwest of Compensation
areas included: N/A Population
and environmental sensitive receivers protected: N/A |
|
Landfill
Gas Hazard |
Environmental benefits of environmental protection measures recommended: The recommended protection measures will
reduce the landfill gas risk to the IWMF operators and
general public (i.e. visitors). In particular, the landfill
gas cut-off trench barrier would prevent landfill gas migrates into the IWMF
site. Compensation
areas included: N/A Population
and environmental sensitive receivers protected: IWMF staff and general public (e.g. those visiting the
education centre) |
N/A |