7
Sewerage and Sewage Treatment implication
7.1.1
According to the latest ARQ
development plan, the location of the cavern is proposed in the vicinity of the
Public Transport Interchange (PTI) and Quarry Park, and the cavern is intended to
be used as a quarry exhibition centre. The sewerage and
sewage implications arising from the cavern development are assessed in this
section.
7.2.1
The proposed cavern is located
in ARQ site and within the East Kowloon sewerage catchment as defined in the
study of Sewerage Master Plan in Central and East Kowloon. The current ARQ Site
is an unsewer area and the existing sewer network is identified in Sau Mau Ping
Road and Po Lam Road which is located at downstream of the ARQ Site.
7.2.2
There are no sewage treatment
facilities proposed in the ARQ Site. Sewage generated from the cavern will be
discharged into a new sewerage network, which will be constructed in the ARQ Site,
and subsequently discharged into the existing sewerage network in Kwun Tong.
The sewage will eventually be collected and treated by Kwun Tong Preliminary
Treatment Works (KTPTW) for onward disposal to the existing Harbour
Area Treatment Scheme (Stage 1) tunnel.
7.3.1 The design shall comply with the
following standards, Codes of Practice and Design Manuals.
Ÿ Sewerage Manual, Parts 1
and 2 (2013 Edition), published by DSD;
Ÿ DSD Technical Circulars and
Practice Notes;
Ÿ General Specification for
E&M Sewerage Facility Installations by DSD;
Ÿ EPD Guidelines for
Estimating Sewage Flows for Sewage Infrastructure Planning Version 1.0, Report
No. EPD/TP 1/05;
Ÿ The Government of the Hong
Kong SAR General Specification for Civil Engineering Works (2006 Edition);
Ÿ DSD Standard Drawings;
Ÿ DSD Stormwater Drainage
Manual (2013);
Ÿ Info Works C S – Model
Acceptance Criteria.
Ÿ BS EN 598 Ductile iron
pipes, fittings, accessories and their joints for sewerage applications (2007);
Ÿ BS 65 Vitrified clay pipes,
fittings and ducts, also flexible mechanical joints for use solely with surface
water pipes and fittings; and
Ÿ BS 5911-1: 2002 –
Specification for Unreinforced and Reinforced Pipes and Fittings with Flexible
Joints;
Ÿ BS EN 295-1 Vitrified clay
pipes systems for drains and sewers (2013).
7.4.1
The design assumptions and
parameters for estimating the sewage flow generated by the cavern development
were submitted to relevant Government departments for review and comment. After
incorporating the comments and the existing data of the Science Museum advised
by Leisure and Cultural Services Department (LCSD),
the following design parameters are adopted:
Quarry
Exhibition Cavern
Ÿ 2.6 m2 floor area per visitor
Ÿ 1 staff in the Cavern serve 13 visitors
Ÿ Unit Flow Factor for Exhibition Centre = 0.28 m3/staff/day
Details
of Cavern Development
7.5.1
The cavern located in the
vicinity of the proposed PTI and Quarry Park is constructed at the level of
approximately +200mPD with dimensions 25m(W) by 11m(H) by 35m(D). The sizes of exhibition
area and supporting facilities (including activity room, demonstration area,
reception counter, entrance and exit buffer, office, store room and etc.) are proposed
to be 1,000m2 and 800m2 respectively in accordance with the
comments from LCSD.
Sewage
Disposal of ARQ Site
7.5.2
The ARQ Site is located at the
most upstream of KTPTW sewerage catchment with an approximate area of 1,810ha
and an existing residential population of approximately 930,000.
7.5.3
Based on the Final Preliminary
Design Report for ARQ development, the estimated total Average Dry Weather Flow
(ADWF) for ARQ development is about 8,863m3/day. The sewage
generated from the ARQ Site will be discharged into the existing sewerage
networks in Sau Mau Ping Road and Po Lam Road and then conveyed by a trunk
sewer pipeline at Tsui Ping Road and King Yip Street. The sewage will
eventually be discharged into KTPTW. The existing sewerage networks have been
reviewed and are considered to be able to receive the additional flow from the ARQ
Site.
7.5.4
The current treatment capacity
of KTPTW is about 10.92m3/s and is not sufficient to cater for the
sequent increase of sewage flow from Kai Tak and Kwun Tong developments. Due to
the new developments, the report of upgrading works project under Agreement No.
CE47/2013(DS) – “Upgrading of Kwun Tong Preliminary Treatment Works – Upgrading
of Kwun Tong Preliminary Treatment Works – Investigation, Design and
Construction” indicates that the treatment capacity of KTPTW will be upgraded
to 13.13m3/s by 2020. Recent information from EPD and DSD also reveals
that the most updated estimates
of PWWF to KTPTW for the design is 13.13 m3/s taking into account
the 2011 based TPEDM data, newly increased population in KTD project, dry
weather flow interceptor, Kwun Tong new development and the sewage flow
generated under the ARQ project.
Sewage
Flow from the Cavern Development
7.5.5
Based on the floor area of the
cavern, the total estimated ADWF for the cavern is about 8.4m3/day
which is about 0.1% of the total ADWF of the ARQ Site. Thus, the additional
ADWF of the cavern will
not have any discernible impacts to the trunk sewerage network for the ARQ Site.
|
Total Exhibition Area (m2)
|
Number of Visitor/Customer
|
Number of Staff
|
Unit Flow Factor (m3/staff/day)
|
Total ADWF Flow (m3/day)
|
|
1,000
|
385
|
30
|
0.28
|
8.4
|
7.6.1
The proposed sewer network in the
ARQ development will be designed to cater for future residential development,
commercial activities and sewage flow arising from the cavern development.
7.6.2
The sewage flow from the cavern development is estimated to be
8.4m3/day, which is around 0.1% of the total sewage flow of ARQ
(i.e. 8,863m3/day), and has been taken in account in the design of
ARQ sewerage system. Therefore, sewerage and sewage implications arising from
cavern development are not anticipated.