1.2 Objectives of the EIA Study
1
INTRODUCTION
1.1.1 The proposed sewerage works in Po Toi O is an environmental enhancement project that aims to improve environmental hygiene of the Po Toi O area.
1.1.2
Po
Toi O is located in the southern part of Sai Kung District, next to Clear Water Bay. There is a small
settlement called Po Toi O village around the bay. There is currently no public
sewerage system for the village. Sewage and wastewater generated by local
residents and local restaurants are treated by septic tanks/soakaway system (STS).
1.1.3
Provision
of proper sewerage system to unsewered villages is a general government policy.
Without centralized public sewage treatment facility, villagers have to
regularly desludge the STS to maintain the cleaning performance and to avoid
overflow of sewage. However, the desludging process may bring along potential
hygiene and associated odour issues. Under the Port Shelter Sewerage Master Plan (SMP), Drainage Services Department (DSD) has
proposed sewerage works at Po Toi O. In addition to improving local
hygiene conditions and removing associated odour problem, the provision of
sewerage is a preventive measure to avoid potential environmental problems due
to insufficient desludging or structural defect of the STS. This can also relieve villagers’ burden to maintain
their STS (e.g. desludging).
1.1.4
The proposed sewerage
works comprise sewage
collection, treatment and disposal facilities at Po Toi O under Port Shelter
Sewerage, Stage 3 – Sewerage Works at Po Toi O (hereinafter referred to as “the
Project”). The
location and details of the facilities are illustrated in Figure 1-1.
1.1.5
The
Project mainly comprises the following works:
i. Provision of village sewerage to the unsewered areas of Po Toi O. The works involve construction of about 800m of gravity sewers and 400m of rising mains;
ii. Construction of a local sewage treatment plant (STP) with Average Dry Weather Flow (ADWF) of about 139m3/day; and
iii. Construction of a submarine outfall of about 385m in length.
1.1.6
The
Project consists of the following designated projects under Part I, Schedule 2
of the Environmental Impact Assessment Ordinance (EIAO):
l Item Q.1 – A sewage treatment plant and portion of sewer alignments in a conservation area;
l Item C.12 (a) (v) and (vii) – A dredging operation which is less than 500m from the nearest boundary of an existing fish culture zone and coastal protection area; and
l Item F.6 – A submarine sewage outfall.
1.1.7
A
project profile (PP-483/2013) has been submitted to the Environmental
Protection Department in February 2013 and a study brief (ESB- 258/2013) has
been issued to the DSD in April 2013.
1.1.8
Cinotech Consultants Limited
(Cinotech) has been
commissioned by the DSD in January 2014 to conduct an environmental impact
assessment for the Project in order to investigate the environmental
acceptability during construction and operation of the proposed sewerage
works. Black & Veatch Hong Kong Limited (hereafter called “the
Engineer”) is the consulting engineer employed by the DSD to design the
proposed sewerage facilities in this Project, among other tasks. Urbis Limited and LWK & Partners (HK) Limited provided expert input in landscape
and visual impact and built heritage impact assessments respectively.
1.2
Objectives of the EIA Study
1.2.1
The
objective of this Assignment is to carry out an environmental impact assessment
to investigate the environmental acceptability during construction and
operation of the sewerage works. Potential impacts, especially on water
quality, were identified and evaluated to address public concerns. Throughout
this process, close contact was made and regular meetings were held with the
DSD and the Engineer to derive practical solutions for the sewerage works
layout, construction and operation methods. A preferred option was determined
that can optimize environmental benefits while minimizing undesirable impacts
(e.g. dispersal of effluent to water sensitive receivers).
1.2.2
Detailed
objectives as per the Study Brief are as follows:
(i)
to
describe the Project and associated works together with the requirements and
environmental benefits for carrying out the Project and the types of designated
projects to be covered by the Project;
(ii)
to
identify and describe elements of community and environment likely to be
affected by the Project and/or likely to cause adverse impacts to the Project,
including natural and man-made environment and the associated environmental
constraints;
(iii)
to
provide information on the consideration of alternative design options of the
Project including location, scale, extent, layout, configuration, design, and
the construction methods with a view to avoiding and minimizing potential
environmental impacts to environmentally sensitive areas and sensitive uses; to
compare the environmental benefits and dis-benefits of different options; to
provide reasons for selecting the preferred option(s) and to describe the part
environmental factors played in the selection of preferred option(s);
(iv)
to
identify and quantify emission sources (including air quality, noise, water quality
and waste, etc. as appropriate) and determine the significance of impacts on
sensitive receivers and potential affected uses;
(v)
to
identify and quantify any potential loss or damage and other potential impacts
to fisheries, flora, fauna and natural habitats;
(vi)
to
identify any potential landscape and visual impacts and to propose measures to
mitigate these impacts;
(vii)
to
identify any negative impacts on sites of cultural heritage and to propose
measures to mitigate these impacts;
(viii)
to
propose the provision of infrastructure or mitigation measures to minimize
pollution, environmental disturbance and nuisance during construction and
operation of Project;
(ix)
to
investigate the feasibility, practicability, effectiveness and implications of
the proposed mitigation measures;
(x)
to
identify, predict and evaluate the residual environmental impacts (i.e. after
practicable mitigation) and the cumulative effects expected to arise during the
construction and operation phases of the Project in relation to the sensitive
receivers and potential affected uses;
(xi)
to
identify, assess and specify methods, measures and standards, to be included in
the detailed design, construction and operation of the Project which are
necessary to mitigate these residual environmental impacts and cumulative
effects and reduce them to acceptable levels;
(xii)
to
investigate the extent of the secondary environmental impacts that may arise
from the proposed mitigation measures and to identify constraints associated
with the mitigation measures recommended in the EIA study, as well as the
provision of any necessary modification; and
(xiii)
to
design and specify environmental monitoring and audit requirements to check the
effective implementation of the recommended environmental protection and
pollution control measures.
1.3.1
The
EIA Report comprises the following Chapters:
l
Ch.
1 Introduction
l
Ch.
2 Project Descriptions
l
Ch.
3 Air Quality Impact
l
Ch.
4 Noise Impact
l
Ch.
5 Water Quality Impact
l
Ch.
6 Terrestrial Ecological Impact
l
Ch.
7 Marine Ecological Impact
l
Ch.
8 Fisheries Impact
l
Ch.
9 Waste Management
l
Ch.
10 Landscape and Visual Impact
l
Ch.
11 Built Heritage Impact
l
Ch.
12 Environmental Monitoring and Audit
Requirements
l
Ch.
13 Summary of Environmental Outcomes
l
Ch.
14 Conclusion
l
Ch.
15 Implementation Schedule of Recommended Mitigation Measures