13.              CONCLUSIONS AND RECOMMENDATIONS

 

Introduction

 

13.1.        This EIA report has provided an assessment of the potential environmental impacts associated with the construction and operation of the Project.  Study has been undertaken in accordance with the EIAO-TM and the Study Brief.  The Implementation Schedules of the recommendations are presented in Section 12.  The principal findings of this Report are summarised in the following sections.

 

Air Quality

 

13.2.        During construction phase, no adverse construction dust impact would be expected at all ASRs in the vicinity of the study area, except at ASR A24.  In order to achieve the air quality objectives (AQO), it was recommended to install 2m high solid fences around the construction site of Pumping Station P2.  With the implementation of the mitigation measure, no exceedance of 1-hour TSP guideline level and 24-hour TSP AQO limit would be anticipated at the ASR.  Notwithstanding this, To further ensure the compliance of the guideline level and AQO limit at the ASRs at all times, the implementation of the Air Pollution Control (Construction Dust) Regulation and the inclusion of good site practices were also recommended.  

 

13.3.        During operation phase, all pumping stations, sequence batching reactor (SBR) feed pump station and sludge dewatering room would be all enclosed and the outlet air from these facilities would be properly treated by deodorization facilities with 99.5% odour removal efficiency before discharge via vent pipes.  With the implementation of all these measures, the predicted odour concentration at the representative ASRs would comply with the odour criterion.  Hence, no unacceptable impacts were predicted.

 

Noise

 

13.4.        Representative noise sensitive receivers (NSRs) were identified and are shown in Figure 34.2. Construction noise impacts from the construction activities such as sewer alignment construction, pumping stations and STW outfall construction, and the operation noise impacts from the pumping stations and STW were identified as key environmental issues for this Project. The potential noise impacts arising from the Project have been assessed and evaluated.

 

13.5.        During the construction phase, the unmitigated noise levels at most of the NSRs would experience noise level exceeding the noise criteria stated in the EIAO-TM.  To alleviate the noise impact, noise mitigation measures including the adoption of good site practices,use of quieter equipment, and restriction on the number of plant operating as well as other possible mitigation measures including erecting of noise screening structures and manual working and the operating time were recommended.  With the recommended mitigation measures, no exceedance of the noise criteria was predicted  during the construction of the pumping stations, except short-term exceedances during sewer construction.  However, eIt is expected that the residual impacts would be transient and localized. xceedances were still predicted during the sewer construction due to the close proximity of the sensitive receivers to the work site of the sewer alignment.  In order to further mitigate the impact, other possible mitigation measure such as hand-dig method was recommended wherever practicable and feasible for areas where exceedances would be expected.  However, the use of hand-dig would be subject to the construction programme and manpower constraints.  Residual noise impacts would be expected to occur during the construction of the sewer alignment due to the close proximity of the NSRs.  Having considered that the construction of the sewer alignment sewer is unavoidable as it is an integral element of the Project and the short duration of the sensitive receivers experiencing the impacts, the residual impacts were considered acceptable.

 

13.6.        During operation phase, no adverse noise impact arising from the operation of the pumping stations were predicted, except Pumping Station P1a.  To alleviate the noise impact, it was recommended to install a silencer at air discharge point of the deodouriser at Pumping Station P1a.  With the recommended mitigation measures applied, no exceedance of both daytime and nighttime noise criterion criteria would be anticipated.

 

Water Quality

 

Construction Phase

 

13.7.        To minimize the potential water quality impacts from the submarine outfall construction, the Horizontal Directional Drilling (HDD) technique would be adopted.  By using the HDD technique, only minor dredging works would only be required at the location of around 480 m from the coastfor approximately 240m offshore pipeline and the diffuser zone of the submarine outfall.  The potential water quality impacts associated with the dredging activities have been assessed by predicting the increases in suspended sediment concentrations due to fine sediment lost to suspension.

 

13.1.        The sensitive receivers identified within the Study Area include the gazetted Fish Culture Zone (FCZ) at Picnic Bay and secondary contact recreation subzone at Mo Tat Wan, which are would be located more thanat least 300 m and 500 m from the proposed dredging works respectively.  With the use of closed grab dredger, 2-layter silt curtains and reduction in dredging rate, the elevations in suspended sediment (SS) concentration generated from the dredging activities at these sensitive receivers would not be expected to exceed the allowable elevations in SS concentrationscomply with the WQO.  To further minimize the potential water quality impacts arising from the dredging works, it was recommended that dredging operation should be only allowed during ebb tide to ensure that sediment plume would not transported into Picnic Bay by tidal current.

13.8.         

 

13.9.        The potential water quality impact arising from the release of contaminants from sediment disturbed during the dredging works was assessed.  It was predicted that because ofowing to the low of sediment contamination in the dredging area, adverse impacts arising from the release of heavy metals, nutrients, and organic compounds would not be expected. 

 

13.10.    Overall, no unacceptable residual impacts would be expected with the implementation of the recommended mitigation measures.

 

Operation Phase

 

13.11.    Potential impacts in relation to the discharge of treated effluent from the outfall for the wet and dry season have been assessed using USEPA CORMIX2 model.  The modelling results indicate that the predicted concentrations of SS, E. coli, and unionised ammonia would satisfy the WQOs, while the predicted TIN levels would exceed the WQO.  The exceedances of WQO for TIN were attributable to the high background TIN levels.  The background level for dry season had already exceeded the limit by more than twice.  Owing to the high background TIN level, exceedance of the WQO limit for TIN would be unavoidable even with a very small contribution from the treated effluent discharge at the submarine outfall.  According to the EPD monitoring data, the predicted TIN levels would fall within the background variations of TIN concentrations at Picnic Bay.    Furthermore, the prediction are were considered to be over-estimated as they were predicted by simply adding the elevated TIN levels from the effluent to the background levels and were not taken account of the beneficial effect of eliminating untreated or partially treated sewage discharges to the Picnic Bay upon the operation of the Project.  The denitrification process in the STW would remove more than 50% of TIN from the sewage and the treated effluent would be discharged at a location of more than 560m from the FCZ.  Hence, the operation of the Project would not induce a water quality impact worse than that without the implementation of the Project.  In fact, the proposed project would improve the water quality of the Picnic Bay by eliminating the discharge of untreated or partially treated sewage into the coastal area of the bay. 

 

13.12.    The potential impact from emergency discharge due to the failure operation of the pumping stations and the STW has also been assessed using the USEPA CORMIX3 model.  Owing to the presence of the gazetted FCZ in the vicinity, adverse water quality impacts on the FCZ during emergency discharge would be anticipated.  In order to minimize the occurrence of emergency discharge as far as possible, an extensive mitigation measures and contingencies were recommended.  With the implementation of the mitigated measures and contingencies, risk the possibility of an emergency overflow occurring occurring would be negligible and the potential water quality impacts would be minimized in the unlikely event that an overflow does occur would be minimized.  Hence, no unacceptable residual water quality impacts would be expected.

 

Sediment Contamination

 

13.13.    Based on the preliminary design, the total volume of dredged material was estimated to be approximately 26,000 m³.  A review of previous field investigation data on marine sediment quality reveals that Category H contaminated mud may be present within the boundary of the study area.  However, the available sediment data were of limited extent and collected about eight years ago, and hence could not fully represent the existing sediment quality of the proposed dredged areas of the present Project.  A preliminary sediment contamination survey was therefore conducted to provide more accurate and updated information on the baseline sediment quality of the proposed dredged areas such that recommendations on the appropriate disposal requirements of the dredged material can be made.  The findings of the sediment contamination survey indicate that the marine sediments to be dredged for the submarine outfall were classified as Category L.  The dredged sediment would therefore be suitable for open sea disposal. 

 

13.14.    The dredging works should be carried out in a controlled manner such that release of sediments into the marine environment would be minimized.  With the implementation of the recommended mitigation measures, residual water quality impacts would not be anticipated.

 

Solid Waste Management

 

13.15.    Wastes generated by the construction works would include workforce wastes, maintenance and chemical wastes, and construction and demolition material.  Provided that the identified waste arisings are handled, transported and disposed of using approved methods and that the recommended good site practices are adhered to, adverse environmental impacts would not be expected.

 

13.16.    Wastes generated during normal STW operations would include inlet screenings, grit from detritors and dewatered sludge.  It has been proposed that the sewage sludge generated from the STW would be dewatered on-site and the sludge cake will would be delivered to Sok Kwu Wan refuse transfer station for disposal to nearby landfill.

 

Ecological Impact

 

13.17.    Construction and operation of the sewage treatment project in Sok Kwu Wan at Lamma might affect the terrestrial and marine environments. The Project would cause a loss of 0.76ha of shrubland/grassland habitat of low ecological value.  Based on site investigations there appeared to be no insurmountable ecological impacts arising from this Project. The overall impacts of project construction and operation on ecology were predicted to be minor.

 

13.18.    Based on the nature of the Project and the baseline conditions of the Study Area, the impacts of project construction and operation on terrestrial ecology were predicted to be minor. A small moist area of shrubland/grassland habitat near Pumping Station P2, which is used by Romer’s Tree Frog and thus of moderate to high ecological value would not be affected. Nevertheless, additional measures to control site runoff for protecting the tree frog site were proposed on a precautionary basis. Impacts on intertidal habitats would not occur on the sand flat but in a limited area on the rocky shore (approximately 250 m² temporary occupied by the platform for HDD works and 10m² permanently occupied by the pipeline), where intertidal fauna were of low abundance and diversity and thus were also predicted to be minor.  HDD technique would be used to avoid direct loss of coral colonies. Construction of the subtidal outfall would involve a temporary seabed loss of 10,400 m² due to dredging for a section of outfall pipeline 480m away from the coastline and the diffusers. Since the seabed loss area is away from shallow subtidal zone and of muddy substrate, no hard corals would be directly impacted by the dredging work, and the seabed which is available for hard coral colonization would not be affected.  Given the distance and the application of silt curtain, indirect impacts from suspended solids during dredging would not be expected.

 

13.19.    Based on results of water quality modelling, during the operational phase, discharge of the effluent would not adversely affect water quality in the Study Area. The predicted TIN levels, however, were considered to be over-estimated as they were calculated by adding the elevated TIN levels directly to the measured background TIN levels. The predicted small increase would, however, fall within the background variations of TIN concentrations at Picnic Bay. In addition, the proposed project would improve the water quality of the Picnic Bay by eliminating the discharge of untreated or partially treated sewage into the coastal area of the bay. Hence no adverse impacts to marine ecology including coral communities in Sok Kwu Wan would be anticipated.  As such, during the operational phase, discharge of the effluent thus would not adversely affect water quality in the Study Area. Hence no adverse impacts to marine ecology inducing coral communities in Sok Kwu Wan would be anticipated.

 

13.20.    The emergency discharge from the pumping stations and STW may be the consequence of pump failure or interruption of the electrical power supply. Water quality impact arising from the emergency discharge of the pumping stations and STW are anticipated.  Sufficient preventive measures would be provided. Standby pumps, standby generators, temporary storage space for sewage, alarm signals and action plan would be prepared. The provision of those measures would prevent the failure of the system and the resulted sewage overflow and emergency discharge. Though the chance is remote, in an extreme case that all the measures fail, contingency plan would be implemented to minimize the water quality impact at the inner part of Picnic Bay and the shallow subtidal zone.

 

13.21.    With the implementation of the mitigation measures recommended, residual ecological impacts may include net loss of grassland habitat and intertidal habitat, are expected to be insignificant and acceptable.  Due to the limited scale of the Project, low ecological value of the fauna and flora recorded, and the minor degree of impacts caused, no ecological monitoring and audit is proposed.

 

13.1.Construction and operation of the sewage treatment project in Sok Kwu Wan at Lamma might affect the terrestrial and marine environments. The Recommended Scheme would cause a loss of 0.76ha of shrubland/grassland habitat.  Based on site investigations there appeared to be no insurmountable ecological impacts arising from this project. The overall impacts of project construction and operation on ecology were predicted to be minor.

 

13.1.Based on the nature of the project and the baseline conditions of the study area, the impacts of project construction and operation on terrestrial ecology were predicted to be minor. Impacts on intertidal habitats would not occur on the sand flat but in a limited area on the rocky shore and thus are also predicted to be minor.  HDD technique would be used to avoid direct loss of coral colonies. Construction of the subtidal outfall would involve a temporary seabed loss of 10,400 m² due to dredging for a section of outfall pipeline 480m away from the coastline and the diffusers. Since the seabed loss area is away from shallow subtidal zone and of muddy substrate, no hard corals would be directly impacted by the dredging work, and the seabed which is available for hard coral colonization would not be affected.  Given the distance and the application of silt curtain, indirect impacts from suspended solids during dredging would not be expected.

 

13.1.Based on results of water quality modelling, during the operational phase, discharge of the effluent would not adversely affect water quality in the Study Area. The predicted TIN levels, however, were considered to be over-estimated as they were calculated by adding the elevated TIN levels directly to the measured background TIN levels. The predicted small increase would, however, fall within the background variations of TIN concentrations at Picnic Bay. In addition, the proposed project would improve the water quality of the Picnic Bay by eliminating the discharge of untreated or partially treated sewage into the coastal area of the bay. Hence no adverse impacts to marine ecology inducing coral communities in Sok Kwu Wan would be anticipated.  Exceedances of WQO limit for TIN is predicted during the normal operation of the sewerage system.  However, the exceedances are attributable to the high background level. The predicted TIN levels, however, were considered to be over-estimated as they were calculated by adding the elevated TIN levels directly to the measured background TIN levels. The prediction was not taken account of the beneficial effect of eliminating untreated or partially treated sewage discharges to the Picnic Bay upon the operation of the proposed project. As such, the potential water quality impact in relation to TIN levels on the marine organisms, would not be expected to be worse than the existing conditions. The impact is thus ranked as minimal. during the operational phase, discharge of the effluent thus would not adversely affect water quality in the Study Area. Hence no adverse impacts to marine ecology inducing coral communities in Sok Kwu Wan would be anticipated.

 

13.1.The emergency discharge from the pumping stations and STW may be the consequence of pump failure or interruption of the electrical power supply. Water quality impact arising from the emergency discharge of the pumping stations and STW are anticipated.  Sufficient preventive measures would be provided. Standby pumps, standby generators, temporary storage space for sewage, sewage transport tanker, alarm signals and action plan would be prepared. The provision of those measures would prevent the failure of the system and the resulted sewage overflow and emergency discharge. Though the chance is remote, in an extreme case that all the measures fail, contingency plan would be implemented to minimize the water quality impact at the inner part of Picnic Bay and the shallow subtidal zone.

 

13.1.With the implementation of the mitigation measures recommended, residual ecological impacts may include net loss of grassland habitat and intertidal habitat natural coast, are expected to be insignificant and acceptable.  Due to the limited scale of the Project, low ecological value of the fauna and flora recorded, and the minor degree of impacts caused, no ecological monitoring and audit is proposed.

 

Fisheries Impact

 

13.22.    Baseline information on the cultured and capture fisheries resources and operations within the Study Area were gathered through desktop study and interviews with mariculturists.  These indicate that Sok Kwu Wan has a capture fishery of above average production for Hong Kong and is a nursery area for some commercially important species.  The most important and sensitive fisheries resource in Sok Kwu Wan is the gazetted Fish Culture Zone.  

 

13.23.    The potential impacts to fisheries sensitive receivers during the construction phase were identified as being the release of suspended sediment and release of ammonia associated with the dredging works required for the construction of about 240 m outfall pipeline and the diffuser section. These dredging works would be conducted no closer than 300m from the FCZ. With reference to water Water quality Quality impact Impact assessment Assessment in Section 5, it was determined that the release of ammonia from sediments during the construction phase would comply with the WQO and would not have any toxic impact to fish in the Study Area.  In order to ensure environmental acceptability, it was determined that mitigation measures to prevent sediment plumes reaching the FCZ would be required and are the same as those recommended for water quality impacts. Potential impacts due to construction of the outfall pipeline would be reduced through the adoption of the HDD construction method. 

 

13.24.    The impact on fisheries sensitive receivers in the Study Area was also evaluated for the operational phase using water quality modelling results.  Based on these predictions, discharge of the effluent would not adversely affect water quality in the Study Area and hence no adverse impacts to fisheries sensitive receivers would be anticipated.

 

13.25.    The small increase in TIN levels owing to effluent discharge was identified as deserving special attention owing to its high background levels (often exceeding WQO) and the importance of nitrogen in mediating algal growth (and hence the potential for red tide formation).  However, according to the EPD monitoring data, the predicted TIN levels would fall within the background variations of TIN concentrations at Picnic Bay.  It is anticipated that the small contribution to TIN levels by effluent discharge would not significantly enhance algal growth, and the potential impact for inducing red tide in Sok Kwu Wan is not rated as being significant.

 

13.26.    Emergency discharge from the pumping stations or STW failure would have the potential to lead to adverse impacts on the FCZ.  With the implementation of the mitigation measures and contingencies as described in Section 5, the risk possibility of an emergency overflow occurring would be negligible and the potential impact on fisheries resources would be minimized.  Compared with the long-termed improvement of water quality of Picnic Bay from the Project and given the recommended measures to prevent and minimise the occurrence of the emergency discharge, no unacceptable residual impact would be expected.

 

13.27.    In conclusion, with the implementation of the recommended mitigation measures, the implementation of the Project at Sok Kwu Wan would be environmental acceptable for the fisheries perspective. 

 

Visual and Landscape Impacts

 

Summary of Landscape Impact Assessment

 

13.28.    In general, the Project will cause slight to moderate adverse landscape impact in the construction phase and negligible to slight/moderate adverse landscape impact in operation phase before the implementation of mitigation measures.  The impacts are localised at the pipeline alignment along First Street, the pumping stations and STW.  They are small in scale, thus, they will not cause serious landscape impact.  The following table shows the dimension of the pumping stations and STW above ground level.

 

	Approximate Dimension (m)			Site Area
	Length	Width	Height*
P1A				202.5m2
Pumping Station	11.85	4.0	300mm	14.22m2
Deodourizer	3	1	3	9m2
Standby Generator	5	4.5	3.5	70m2
Control Kiosk	2.6	1.5	1.5	5.85m2
P1B				241 m2
Pumping Station	11.85	4.0	300mm	14.22m2
Deodourizer	3	1	3	9m2
Standby Generator	5	4.5	3.5	78.75m2
Control Kiosk	2.6	1.5	1.5	5.85m2
P2				310 m2
Pumping Station	11.85	4.0	300mm	14.22m2
Deodourizer	3.5	1.5	3.2	9m2
Standby Generator	5	6	3.5	105m2
Control Kiosk	2.6	1.5	1.5	5.85m2
STW	Refer to Figure 10.13 for layout	Refer to Figure 10.13 for layout	7.0m max.	1529 m2

 

13.29.    Vegetation (LS1) loss will be small - 1% (2283m²)of the Study Area.  Mitigation measures at construction phase include minimise damage and protect existing vegetation, conservation of topsoil for reuse, careful transplant of the identified tree, short excavation sections and immediate back filling upon completion, and compensatory planting will alleviate the adverse impact to negligible to slight adverse.  However, at the Exposed Coastline area (LCA3), the presence of the sea-borne construction traffic at the outfall site will disturb the natural context of the coastline, the landscape impact will be relatively high - slight/moderate adverse.  Other than the new ancillary buildings (STW, 3 nos. pumping stations), the impacts at construction phase are reversible.  Mitigation measures in the operation phase include architectural and soft landscape finishes to the ancillary buildings and planting to reformed slope to establish a coherent context within the overall landscape.

 

Summary of Visual Impact Assessment

 

13.30.    In general, the major visual impact is during construction where the sewer is at parts adjacent to residential units and to the waterfront restaurants which leads to slight/moderate to moderate adverse visual impact.  Mo Tat Wan (VSR6) will have a moderate adverse impact during construction since it is close to the location of the outfall affecting its tranquil quality.  If night lighting is required for the marine fleets near Mo Tat Wan, the light source should be directed away from the residential units.  Mitigation measures in construction phase includes short excavation sites and immediate backfilling upon completion of sections, minimise damage to vegetation along footpath, and use of site hoarding appropriate to the natural site context to screen trenches.  Mitigation measures in operation phase include architectural and soft finishes to the pumping stations and STW appropriate to its site context, planting to reformed slope behind the STW, and appropriate paint finishes to the exposed section of pipeline.  Upon implementation of the mitigation measures, the visual impact in operation phase will be reduced to negligible to slight.

 

Evaluation of the Project

 

13.31.    The major adverse landscape and visual impacts occur in the construction phase, and these impacts are reversible with the completion of construction.  Since the major length of the pipeline alignment is underground and the scale of the ancillary buildings is relatively small, the landscape and visual impact in operation is limited. 

13.32.    Overall in the context of Annex 10 of the EIAO-TM, the landscape and visual impacts are acceptable with mitigation measures.

 

Overall Conclusion

 

13.33.    The proposed sewerage system would serve to collect and transfer the sewage arising from the existing villages including restaurants to the proposed STW and submarine outfall for proper treatment and disposal.  This would achieve the effect of eliminating untreated or partially treated sewage discharges to Picnic Bay.  This represents the major benefit of the Project, not only in the respect of water quality improvement to the Bay but also to the local environment in the residential areas by eliminating unhealthy, malodorous and potentially visually unpleasant surface discharges.

 

13.34.    This EIA has identified potential environmental impacts of various nature including air quality, noise, water quality, sediment contamination, solid waste, ecology, fisheries and landscape and visual associated with the implementation of the Project.  The potential environmental impacts would be expected to arise during both construction and operational stages if no mitigation measures are in place.

 

13.35.    With the recommended mitigation measures applied, the Project would be environmentally acceptable and no unacceptable residual impacts would be anticipated.  Table 13.1 summarises the environmental outcomes/benefits from the implementation of the Project and the recommended mitigation measures.  The schedule of implementation of the recommended mitigation measures has been provided in Chapter 12 – Implementation Schedule.  Monitoring requirements have also been specified in a separate EM&A Manual to ensure proper implementation of the recommended mitigation measures. 

 

 

 

Table 13.1       Summary of Key Environmental Outcomes/benefits

 

Issue	Mitigation Measures and Environmental Outcomes/Benefits
The Project	Provision of a new sewage collection, treatment and disposal facilities for Sok Kwu Wan area in order to:   ·         Eliminate the direct discharges of untreated or partially treated sewagegenerated from approximately 1300 residents, 6000 day visitors and restaurants in Sok Kwu Wan area into coastal area of Picnic Bay in 2016 (which are equivalent to the ultimate population figures) as well as from Lo So Shing and Mo Tat Wan which would have total residents of approximately 532 in 2016. ·         Improve the water quality of Picnic Bay. ·         Improve the local environment in the residential areas by eliminating unhealthy, malodorous and potentially visually unpleasant surface discharges.
Option Selection & Design	The locations and design of the proposed sewer alignment, pumping stations, STW and submarine outfall are considered environmental friendly due to the following reasons:   ·         Avoid or reduce impacts on sites of archaeological interest and cultural heritage importance (Lo So Shing Archaeological Site). ·         Avoid reclaiming land for STW construction. ·         Reduce the risk of untreated sewage leakage by selecting the route with shorter pipeline on land. ·         Minimizethe encroachment into private lot and the LCSD playground. ·         Minimize the loss/disturbance of vegetated areas. ·         Avoid direct impact on coral habitats with the use of HDD. ·         Minimize potential water quality impacts on nearby sensitive receivers by extending the outfall length, eliminating the need of reclamation, and using of no-dig method for inshore section of the outfall pipeline. ·         Improve water quality of Picnic Bay by eliminating the discharge of untreated or partially treated sewage and providing a full secondary treatment with nitrogen removal and UV disinfection unit. ·         Minimize the extent of construction dust and noise impacts (i.e. the selected route would avoid affecting the receivers in Lo So Shing)
Air Quality –Construction Phase	2m high solid fence around construction site of Pumping Station P2 and dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation are proposed to protect the nearby ASRs.   All ASRs would be protected to comply with AQQ and EIAO-TM standards.
Air Quality –Operation Phase	All pumping stations, sequence batching reactor (SBR) feed pump station and sludge dewatering room would be enclosed and installed with deodorisation facilities.   All ASRs would comply with of EIAO-TM odour standard.
Noise – Construction phase	Use of quieter plants, limiting number of some powered mechanical equipment, use of noise screening structures and manual working method are proposed to protect the NSRs located near the pumping stations and along the sewer alignment.   All NSRs comply with EIAO-TM noise standards, except short-term residual impact during sewer construction.
Noise – Operation phase	Installation of a silencer with at least 8 dB(A) noise reduction at Pumping Station P1a is recommended.   All NSRs would be protected to meet both daytime and nighttime noise criteria.
Water Quality – Construction Phase	Use of HDD for the inshore section outfall pipeline installation, reduction of dredging rate and use of 2-layer silt curtains are recommended to protect the FCZ at Picnic Bay and secondary contact recreation subzone at Mo Tat Wan.   The FCZ and secondary contact recreation subzone would be protected to be within the relevant WQO.
Water Quality – Operation Phase (Normal Operation)	Provision of full secondary treatment with nitrogen removal and UV disinfection and disposal of treated sewage at a long submarine outfall near the mouth of Picnic Bay.   The FCZ and secondary contact recreation subzone would comply with WQO, except WQO limit for TIN due to the high background level which has already exceed the limit.  The predicted TIN levels would fall within the background variations of TIN levels at Picnic Bay.
Water Quality – Operation Phase (Emergency Discharge)	Mitigation measures such as provision of standby pump and standby generator, 24-hour temporary storage and contingency measures are recommended to minimize the occurrence of emergency discharge and potential water quality impact if an overflow does occur, in order to protect the FCZ at Picnic Bay.   With the implementation of the recommended mitigation measures and contingencies, the occurrence of emergency discharge and the residual impacts in the unlikely event that an overflow does occur would be minimised.
Ecology	Use of HDD for the inshore section of outfall pipeline would avoid the loss of coral habitats and reduce the temporary seabed loss due to dredging.   Fencing and labelling of uncommon tree species is proposed to avoid direct or indirect disturbance during construction.    No significant and unacceptable residual impact would be expected.
Fisheries	With the implementation of the mitigation measures recommended for the water quality impact, no unacceptable residual impact on fisheries would be expected.
Landscape and Visual Impact	Appropriate construction practice, design and surface treatment of the built elements and appropriate soft landscape treatment within available areas of the Project are recommended to mitigate the potential landscape and visual impacts.   Landscape and visual impacts would be acceptable with the recommended mitigation measures.