9. Summary of Environmental Outcomes

9.1 Introduction

9.1.1 This EIA study predicted that, with the implementation of the recommended mitigation measures, the Project would be environmentally acceptable with no adverse residual impacts on the population and environmentally sensitive resources. Table 9‑1 summarises the environmental outcomes and benefits that accrued from the environmental considerations and analysis during the EIA process and the implementation of environmental control measures of the Project. The requirements for the EM&A programme have been recommended, where necessary, to check for the compliance with environmental legislation and standards.

Table 9‑1 Summary of Key Environmental Outcomes

Area / Issue	Environmental Outcomes and Mitigation Measures
The Project	Based on the preferred option of the facilities, the proposed offices-cum-vehicle depot will be constructed in the form of a five-storey building occupying a site area of approximately 8,278m². The lowest three floors will provide vehicle maintenance facilities, vehicle washing facilities for carrying out general vehicle repair and washing activities as well as providing parking spaces for the FEHD vehicle fleet. Offices and stores will be mainly located on the higher floors, with green roof design providing substantial landscape features. The offices-cum-depot would mainly include the following: · Parking spaces (about 140 nos.); · Covered vehicle maintenance workshop including 3 vehicle repair bays; · Covered vehicle washing facilities including an automatic vehicle washing bay and 2 manual vehicle washing bays; · Storage rooms; · Offices; · Special ancillary facilities, including underground waste lubrication oil tank; underground oil interceptor; scrap metal yard; dangerous goods (DGs) store; · Associated plant rooms; and · Toilets and shower rooms.
Environmentally Friendly Design Recommended	Building Design To minimise the potential environmental impacts, in particular on noise and air quality perspectives, non-open building form was recommended for vehicle repairing and washing activities, which are now to be located at ground floor and refined and covered by the above floors. Facilities Layout Layout design was investigated in details in order to strike the balance between operational needs, as well as catering environmental considerations. Activities with potential environmental implication / nuisance were located in a confined manner as possible. Vehicle repairing bays and workshop is recommended to be covered at ground floor, surrounded by storerooms for noise screening and buffering purpose as possible. In addition, solid partition wall is proposed to the manual vehicle washing bays to entirely isolate from the pedestrian from potential nuisance. Moreover, to enhance the visual quality of the Depot, substantial greenery features were considered, including vertical green walls and green roofing. Ventilation and Local Exhaust Design A vast amount of openings are proposed at the building façade to optimise the use of natural ventilation at the car parking area at lower floors. Mechanical ventilation is only designed for standby forced ventilation system. As a result of rare usage of the associated substantial mechanical ventilation system, potential noise nuisance from this fixed plant system could be minimised. On the other hand, for those activities with potential environmental nuisance including vehicle repairing activities at the workshop and vehicle washing, controlled mechanical ventilation with sufficient forced air changes is desired, rather than merely relying on natural ventilation. In addition, ventilated exhaust is to be treated prior to discharging to the atmosphere. Various gas treatments were evaluated and the most appropriate technology with proven removal efficiency (eg. activated carbon filter, bio-oxygen generator, chemical scrubber) will be applied. Location and orientation of the local exhaust were carefully examined to ensure sufficient dispersion and to avoid direct impact to the nearby receivers. Construction Method Construction of the depot would involve various typical work stages and conventional building services works. As such, consideration of beneficial construction method is focused on the design of the foundation works. According to the ground condition of the Site, two foundation types, namely driven steel-H piling (percussive) and bored piling (non-percussive) are considered to be technically viable for the Project. With various factors including environmental benefits, programming, engineering feasibility, cost-effectiveness, etc, driven steel H-pile is thus recommended. Traffic Routings At the early stage of the Project, incoming and outbounding traffic routings were developed based on ease and need of operation. During project development and public engagement, local concerns on the proposed traffic routings were received and thus modification to the routings were considered necessary requiring substantial changes in order to address the concerns.
Population and Environmentally Sensitive Areas Protected	With the adoption of the environmentally friendly design in the preferred option, the major environmental sensitive receivers will be protected. This preferred option is determined based on the comparison of the environmental benefits and dis-benefits of the various options and alternatives and has been selected on the basis that it minimises environmental impacts and presents overall environmental benefits over the other options and is considered the optimum scheme from an environmental perspective.
Air Quality	Air quality impact and odour analysis have been conducted for the construction and operation of the Depot. For the construction aspect, there would be no major earthworks carried out for the site formation works for the Project site. With the implementation of sufficient dust suppression measures as stipulated under the Air Pollution Control (Construction Dust) Regulation, adverse construction dust impact would not be anticipated. For the operation of the Depot, no adverse air quality impact would be anticipated as there would be limited vehicular emissions from the repairing and parking activities of the Project, considered with cumulative effect of emissions from open roads networks within the Study Area (500m from Project boundary). Results show that the predicted maximum 1-hour, daily and annual average NO₂ and maximum daily and annual average RSP concentrations at the representative ASRs and within the Study Area would comply with the AQOs. No mitigation measures are required. Lastly, taking into account the fact that potential odour emission and minimal spread in the Depot to be localised only in the washing bay, together with the provision of mechanical ventilation adopting with proper installation and maintenance of deodourisation system, as well as the dilution along considerable buffer distance between the Depot to the adjacent ASRs, potential odour nuisance associated with the operation of the Depot is anticipated to be negligible.
Noise	Noise impact assessment has been conducted for the construction and operation of the Depot. Regarding construction phase, with the implementation of the recommended mitigation measures such as the use of QPME employed in the works, temporary noise barriers, noise jackets, mufflers, and limiting the number of plants operated concurrently, adverse construction noise impact is not anticipated. Concerning fixed plant noise during operation, with the implementation of the mitigation measures for both workshop vehicle repair activities and MVAC installation to be carried out under the covered area to be operated during daytime and evening periods only and acoustic treatments, such as acoustic silencers, acoustic louvres to be applied to the MVAC installations in order to achieve the specified maximum allowable SWL, adverse impact to the NSRs due to the fixed plant noise would not be anticipated during operation phase. For off-site traffic noise, based on the insignificant off-site traffic generation and routings for the Project development, the assessment results demonstrate that the operation of the FEHD Depot would introduce insignificant traffic noise impact less than 1.0 dB(A) on all representative NSRs for short-term and in the long run.
Water Quality	Potential water pollution sources have been identified as construction site run-off, sewage from workforce, and potential risk of chemical spillage. Mitigation measures including the implementation of the construction site practices in accordance with the EPD’s ProPECC PN 1/94 Construction Site Drainage, provision and management of portable toilets on-site, and preventive measures to avoid accidental chemical spillages are recommended to mitigate any adverse water quality impacts, based on which adverse residual impacts would not be anticipated. Furthermore, there would be insignificant sewerage and sewage treatment implications during the operation of this Project, and adverse water quality impact would not be anticipated with the implementation of the recommended mitigation measures based on the findings of this EIA study.
Waste Management Implication and Land Contamination	The waste streams that would be generated during the construction phase of the Project were identified and evaluated in terms of their quantity, type and nature etc. Opportunities for minimising waste generation via on-site sorting and reusing excavated fill materials are identified. Preventive measures have been recommended for the Contractor to implement during the construction phase to address any potential environmental impacts. The waste streams that would be generated during the operation phase of the Project were also identified and evaluated. Measures to ensure proper treatment and disposal of these wastes have been made. With regard to the historical land uses and current site condition, there was no sign of land contamination due to the past and current activities at the Site. For the future operation, as the Site will be paved and good practice for storage and handling of limited DGs, chemicals and chemical wastes will be followed, leakage of contaminants causing quantifiable adverse land contamination impacts would therefore not be anticipated. Provided that the recommendations set out are implemented, unacceptable environmental impacts would not be expected to arise from the handling, storage, transportation and disposal of wastes and chemicals during both the construction and operation of the Project.
Landscape and Visual	With the implementation of mitigation measures such as control of construction activities and temporary landscape treatment during construction phase, the proposed Depot will inevitably result in some landscape impact but no adverse visual impact during the construction phase. On the contrary, ground floor planting, vertical greening and roof gardens will be provided for the proposed Depot during operation phase. Both landscape and visual impact would become negligible in Year 10 when the mitigation measures are already established. Comparing with the original setting of the Site before the proposed Project where undesirable and weedy species are located at the Site, the overall landscape character and visual quality of the Site would be improved, with the provision of landscape design including ground floor planting at pedestrian zone, vertical greening and roof gardens for the proposed Depot. According to Annex 10 of EIAO-TM, the landscape and visual character of the Site have been complemented and therefore landscape and visual impact arising from the proposed Depot is considered as beneficial.

9.2 Summary of Measures Adopted to Minimize Environmental Impacts

9.2.1 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 in Table 9‑2 for easy reference and they are not exhaustive. For details, please refer to the relevant chapters and appendices as appropriate.

Table 9‑2 Summary of Measures Adopted to Minimize Environmental Impacts

Area / Issue	Measures Adopted to Minimize Environmental Impacts
Alternatives Adopted and Environmentally Friendly Design Recommended	· Siting – The proposed Site locates adjacent to the CLP Tai Kok Tsui Substation, which provides screening acoustic effect to the nearby noise sensitive receivers of schools. · Building Design – Non-open form is adopted to minimize potential noise and air quality nuisance. · Layout – Repairing activities are to be located at ground floor surrounded by storerooms for noise screening and buffering purpose and solid partition wall is proposed to manual washing bays to entirely isolate the pedestrian from potential nuisance. Substantial greenery features are proposed to roof area to enhance visual quality. · Ventilation – Mechanical ventilation is only designed for standby forced ventilation, such that potential noise nuisance from fixed plant is minimized. Adequate ventilation equipped with odour removal treatment for areas of repairing workshops and vehicle washing is to be provided to minimize potential odour nuisance. · Exhaust Location – Location and orientation of local exhaust were carefully examined to ensure sufficient dispersion and to avoid direct impact to nearby receivers. · Traffic Routing of Vehicle Fleets – Alternative traffic routes were examined and adopted to avoid utilizing those public concerned junctions and roads to minimize potential air quality and noise impacts.
Air Quality	· Construction – Sufficient dust suppression measures and good site practices are to be adopted to minimize potential dust impact by construction activities. · Operation – Adequately designed ventilation system equipped with odour removal facilities are to be provided for repairing and vehicle washing bays to minimize potential odour nuisance to the environ.
Noise	· Construction – A number of available construction noise mitigation measures are to be adopted to minimize construction noise, including: · selection and optimization of construction programmes, avoidance of parallel operation of noisy PME, and/or reduction in the proportion of usage of PME during noise sensitive periods such as school examination period; · use of “quiet” PME and working methods; · use of temporary at-source noise mitigation measures such as noise barriers, noise enclosures, noise jacket and mufflers; and · use of good site practice to limit noise emission from construction site. · Operation – Acoustic treatment such as acoustic louvres, scilencers and enclosures would be applied to various noisy plants. Furthermore, major noisy repairing activities are to be carried out in covered workshops and limited in nighttime period to minimize fixed plant noise during operation.
Water Quality	· Construction – General good site practice, such as perimeter drains, silt removal facilities, construction programming, dusty stockpiling covering, is to be implemented to minimize potential water quality impact during construction phase. · Operation – Proper sewer connections are to be provided to collect and divert sewage generated from Depot operation. Adequately designed petrol interceptors and sedimentation tanks will be provided to oily and silty wastewater polluting water system.
Waste Management Implication and Land Contamination	· Construction – Typical good site practices are to be adopted to minimize generation of C&D waste and chemical spillage. · Operation – The Depot covering vehicle washing bays, maintenance workshop and storage areas for DGs, chemicals and wastes are to be impervious and properly paved by concrete. Adequate drainage management system including oil interceptor is to be provided. Emergency procedures for accidental spillage of chemicals are to be formulated and regularly reviewed and trials, to minimize chance of contaminating land / soil.
Landscape and Visual	· Construction – Control of construction activities and temporary landscape treatment, such as applying hoardings, are to be implemented to minimize impact by construction activities. · Operation – In order to enhance the landscape and visual quality, substantial greenery features are to be provided for the building, including green roof garden, vertical greening and various hard landscape features.

Environmental Monitoring and Auditing

9.2.2 In addition to the mitigation measures as described above (see more details in the Implementation Schedule in Chapter 12), environmental monitoring and auditing programme would be implemented to cover various aspects of concern. An Independent Environmental Checker would also be employed to ensure that all the necessary mitigation measures are implemented in a timely and orderly manner.

Overall

9.2.3 Mitigation measures and good site practices to minimize the environmental impacts were recommended throughout the impact assessments of air quality, noise, water quality, waste management, land contamination and landscape and visual. These measures were consolidated in Chapter 12 Implementation Schedule which specifies the responsibility, methodology and timing of implementation, such that effective and appropriate implementation of the measures can be assured.