PWSC(1999-2000)54
For discussion
on 16 June 1999
ITEM FOR PUBLIC WORKS SUBCOMMITTEE
OF FINANCE COMMITTEE
HEAD 704 - DRAINAGE
Environmental Protection - Sewerage and sewage treatment
| 52DS - | Ting Kau development: sewerage and sewage treatment works including submarine outfall |
126DS - Sham Tseng sewerage and sewage treatment and disposal facilities
Members are invited to recommend to Finance Committee -
- the upgrading of part of 52DS and 126DS, entitled "Ting Kau sewerage stage 1 and Sham Tseng sewerage stage 2 phase 2", to Category A at an estimated total cost of $422.0 million in money-of-the-day prices;
- the retention of the remainder of 52DS, retitled "Ting Kau sewerage stage 2", in Category B; and
- the retention of the remainder of 126DS, retitled "Sham Tseng sewerage stage 3", in Category B.
PROBLEM
There are no proper sewerage facilities in Ting Kau, Sham Tseng and Tsing Lung Tau. Sewage from these areas is discharged to the nearby coastal waters without proper treatment, causing serious water pollution.
PROPOSAL
2. The Director of Drainage Services, with the support of the Secretary for Planning, Environment and Lands, proposes to upgrade part of 52DS and 126DS to Category A for the construction of Ting Kau sewerage stage 1 works and Sham Tseng sewerage stage 2 phase 2 works. The total estimated cost of the works involved is $422.0 million in money-of-the-day (MOD) prices ($38.7 million from project item 52DS and $383.3 million from project item 126DS).
PROJECT SCOPE AND NATURE
52DS
3. Project 52DS aims to provide a sewerage system to collect sewage from Ting Kau and convey it to the proposed sewage treatment works at Sham Tseng for proper treatment and disposal. The part of the project we now propose to upgrade to Category A comprises the construction of about four kilometres of sewers and rising mains of diameters ranging from 150 to 400 millimetres along Castle Peak Road (Ting Kau Section) from Lido Beach to the proposed sewage treatment works at Sham Tseng.
4. The remainder of 52DS for retention in Category B comprises pumping stations, rising mains and sewers in Ting Kau.
126DS
5. Project 126DS aims to provide sewage treatment works and a submarine outfall at Sham Tseng to serve the Ting Kau, Sham Tseng and Tsing Lung Tau areas. It will also provide a sewerage system to collect sewage from Sham Tseng and Tsing Lung Tau and convey it to the proposed sewage treatment works. The part of the project we now propose to upgrade to Category A comprises the construction of -
- sewage treatment works with a 160-metre long submarine outfall on the reclaimed land south of Garden Company Limited;
- a sewage pumping station near Sham Tseng Kau Tsuen; and
- about 1.8 kilometres of sewers and rising mains of diameters ranging from 225 to 400 millimetres along Castle Peak Road (Tsing Lung Tau Section) from Tsing Lung Tau to the proposed Sham Tseng sewage treatment works.
6. The remainder of 126DS for retention in Category B comprises pumping stations, rising mains and sewers in Sham Tseng and Tsing Lung Tau areas.
JUSTIFICATIONS
7. Ting Kau, Sham Tseng and Tsing Lung Tau have a population of around 28 000 but the areas are at present unsewered.
8. In February 1989, Director of Environmental Protection appointed consultants under 92DS "Tsuen Wan, Kwai Chung, Tsing Yi sewerage masterplan study - consultants fees and investigations" to review the sewerage requirement in Tsuen Wan, Kwai Chung and Tsing Yi including Sham Tseng and Ting Kau. The study recommended, inter alia, the provision of a centralised sewage treatment works and submarine outfall at Sham Tseng for Sham Tseng and Ting Kau areas and a comprehensive sewerage system stretching from Approach Beach in the east to Tsing Lung Tau in the west.
9. As a result of recent housing developments in the three areas including those in the previous sites of the Union Carbide Depot and the San Miguel Brewery, we estimate that the population in the area will increase to 29 500 in 2003 , to 37 000 in 2006, to 44 000 in 2008 and to around 55 000 in 2011. At present, about 8 000 cubic metres (m3) of sewage is generated daily in the three areas. In the absence of public sewerage facilities, about 2 300 m3 of this sewage is to be handled by private treatment facilities while another 5 700 m3 of sewage is discharged to the nearby coastal waters without adequate treatment, causing serious water pollution. We estimate that the daily sewage volume will increase to about 8 500 m3 in 2003, to 11 000 m3 in 2006, to 13 000 m3 in 2008 and to about 16 500 m3 in 2011. To rectify this situation, we propose to construct a sewage treatment works with the capacity to treat 16 500 m3 of sewage per day, a submarine outfall at Sham Tseng, and a comprehensive sewerage network including sewers and pumping stations to collect and convey the sewage generated from the three areas, including sewage currently handled by private facilities, to the proposed sewage treatment works for proper treatment and disposal. We cover the whole package of works under two project items, namely 52DS and 126DS.
FINANCIAL IMPLICATIONS
10. We estimate the capital cost of the proposed works to be $422.0 million in MOD prices (see paragraph 11 below), made up as follows -
| $ million
|
|---|
| 52DS | 126DS
|
|---|
| (a) Sewers | | 26.9 | | 8.4
|
| (b) Sewage treatment plant | | - | | 213.0
|
|
A breakdown by man months of the estimates for consultants fees is at the Enclosure.
11. Subject to approval, we will phase the expenditure as follows -
| Year | $ million
(Dec 1998) | Price
adjustment
factor | million
(MOD)
|
|---|
| 52DS | 126DS | | 52DS | 126DS
|
|---|
| 2000 - 2001 | 0.5 | 20.0 | 1.06217 | 0.5 | 21.2
|
| 2001 - 2002 | 3.0 | 58.0 | 1.09934 | 3.3 | 63.8
|
| 2002 - 2003 | 9.5 | 90.0 | 1.13782 | 10.8 | 102.4
|
| 2003 - 2004 | 9.5 | 70.0 | 1.17765 | 11.2 | 82.4
|
| 2004 - 2005 | 7.5 | 60.0 | 1.21886 | 9.1 | 73.1
|
| 2005 - 2006 | 3.0 | 32.0 | 1.26152 | 3.8 | 40.4
|
| ______ | ______ | | ______ | ______
|
| 33.0 | 330.0 | | 38.7 | 383.3
|
| ______ | ______ | | ______ | ______
|
12. We have derived the MOD estimates on the basis of the Government's latest forecast of trend labour and construction prices over the period 2000 to 2006.
13. We will tender the proposed sewage treatment works, submarine outfall and sewage pumping station at Sham Tseng under a lump sum design-and-build contract with clearly defined scope of works. We will allow for price adjustment to the tender price as the contract will exceed 21 months.
14. Director of Highways plans to start two proposed road works projects along Castle Peak Road, namely 365TH "Castle Peak Road improvement between area 2 and Sham Tseng, Tsuen Wan" and 553TH "Castle Peak Road improvement between Sham Tseng and Ka Loon Tsuen, Tsuen Wan" in May 2000 for completion in February 2004. To minimise the impact of the sewerage works on the road users of Castle Peak Road, we will incorporate the construction of sewers along Castle Peak Road into the Highways Department's Castle Peak Road improvement projects. Such arrangement will also avoid conflicts between different contractors working at the same location. We will incorporate the sewerage works into the Highways Department's road works contract on a remeasurement basis. We plan to start the sewerage works in May 2000 for completion in February 2004 to tie in with the road works.
15. We estimate the annual recurrent expenditure for operation and maintenance of the proposed sewerage facilities to be $12.0 million.
16. Based on the current level of expenditure on operation and maintenance of sewerage facilities, the proposed works by itself will lead to an increase in the recurrent expenditure of providing sewage services of about 1.7% in real terms which will need to be taken into account in determining sewage charges.
PUBLIC CONSULTATION
17. We consulted the Tsuen Wan District Board on the proposed location of the sewage treatment works in May 1993. The District Board supported the construction of sewage treatment works on the reclamation in Sham Tseng. In September 1995, we briefed the Environmental Affairs Committee of the District Board on the environmental assessment of the project. The Committee supported the implementation of the project. We consulted the Environmental Affairs Committee of the Provisional Tsuen Wan District Board again in May 1998. The Committee supported the implementation of the project.
18. We consulted the LegCo Panel on Environmental Affairs on the proposed project on 11 June 1999. The Panel focused mainly on the possibility of providing a treatment regime involving a secondary treatment plant with disinfection capabilities as opposed to a chemically enhanced primary treatment (CEPT) plant with disinfection capabilities as presently proposed. We undertook to provide an estimate of the cost implications for the construction of a secondary treatment plant for comparison.
ENVIRONMENTAL IMPLICATIONS
19. Section 9(2)(c) of the Environmental Impact Assessment Ordinance (EIAO) stipulates that projects which were gazetted under the Foreshore and Sea-bed (Reclamations) Ordinance (FSRO) before the commencement of the EIAO in April 1998 will be exempted from the provisions of EIAO. As the sewerage package for Ting Kau and Sham Tseng was gazetted under the FSRO before reclamation works at Sham Tseng took place from 1996 to 1997 for the proposed Sham Tseng sewage treatment works, it is therefore an exempted project under the EIAO. That said, we have assessed the environmental impacts of the sewerage works during the construction and operational stages under an Environmental Impact Assessment (EIA) study completed in August 1995. We have lodged the EIA report in the EIAO Register.
20. The EIA study concluded that the environmental impacts of the project, including the effects of effluent discharge, sludge handling and disposal, noise and odour can be mitigated to within the established standards and guidelines. After completion of the project, pollution problems currently caused by the discharge of untreated sewage into the coastal waters of Ting Kau, Sham Tseng and Tsing Lung Tau will be reduced.
21. We shall implement the mitigation measures recommended in the EIA study. For short term impacts during construction, we will incorporate standard pollution control measures in the contract to control construction impacts to within the established standards and guidelines. We estimate the cost of implementing the environmental mitigation measures to be about $9.3 million. We have included this cost in the overall project estimate.
LAND ACQUISITION
22. The proposed Ting Kau sewerage stage 1 works and Sham Tseng sewerage stage 2 phase 2 works do not require any land acquisition.
BACKGROUND INFORMATION
23. We included 52DS "Ting Kau development: sewerage and sewage treatment works including submarine outfall" in Category AB1 in July 1988. The original scope of the project was to provide permanent sewage collection and disposal facilities, including a submarine outfall, pumping station and sewage treatment works, for developments in the hinterland of Ting Kau Beach. In August 1990, we revised the scope of works of 52DS for the provision of the sewage collection system to direct the sewage from Ting Kau to the proposed treatment facilities at Sham Tseng.24. In November 1991, we upgraded 126DS "Sham Tseng sewerage and sewage treatment and disposal facilities" to Category B for the provision of the proposed sewage treatment works and submarine outfall, and the sewage collection system for Sham Tseng and Tsing Lung Tau. Concurrently, we consulted the Town Planning Board (TPB) on reclaiming a piece of land to accommodate the proposed Sham Tseng sewage treatment works. Some members of the TPB suggested the idea of identifying a suitable cavern site to house the works rather than a reclamation. Accordingly, we conducted a geological assessment study and compared the options of reclamation vis-a-vis cavern site. We completed the study in early 1993, confirming that the reclamation option was a better arrangement. This was subsequently endorsed by the TPB in mid 1993. We then proceeded with the EIA study for the whole sewerage scheme and commissioned consultants in May 1995 to undertake site investigations and design for the Ting Kau and Sham Tseng sewerage works under block allocation Subhead 4006DX "Consultants' design fees and charges and major in-house investigations for drainage projects'.
25. On 2 February 1996, Finance Committee approved the upgrading of part of 126DS to Category A as 279DS entitled "Sham Tseng sewerage stage 1 Sham Tseng reclamation" at an approved project estimate of $176 million in MOD prices. The reclamation works started in February 1996 and were completed in June 1997. The reclaimed land will accommodate the proposed sewage treatment works under 126DS and will also provide for other land uses.
26. On 30 October 1998, Finance Committee approved the upgrading of another part of 126DS to Category A as 218DS entitled "Sham Tseng sewerage, stage 2 phase 1" at an approved project estimate of $158.2 million in MOD prices for the Sham Tseng sewerage advance works. We plan to start the works in July 1999 for completion in August 2001.
27. We plan to start a design-and-build contract for the proposed pumping station, sewage treatment works and submarine outfall in April 2000 for completion in April 2003. Upon completion, these sewerage facilities will start to accept sewage flow. A commissioning period of twelve months will be required to conduct the required testing for the facilities and collect adequate data to ensure that the sewage treatment works is performing in accordance with the design requirements.
28. We will implement the remaining sewerage works for Ting Kau, Sham Tseng and Tsing Lung Tau areas under the "Ting Kau sewerage stage 2" works and the "Sham Tseng sewerage stage 3" works. Upon completion of the whole sewerage scheme in March 2004, Ting Kau, Sham Tseng and Tsing Lung Tau will have a sewerage system with treatment capacity of 16 500 m3 per day to meet the sewage treatment demand up to the year 2011.
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Planning, Environment and Lands Bureau
June 1999
Enclosure to PWSC(1999-2000)54
52DS - Ting Kau development: sewerage and sewage treatment works including submarine outfall
Breakdown of estimates for consultants' fees
|
Consultants' staff costs
| | Estimated
man
months
| Average
MPS
salary
point
| Multiplier
factor
| Estimated
fee
($ million)
|
|---|
|
(a) Consultants' fees for construction stage
| Professional
Technical
| 0.5
1
| 40
16
| 2.4
2.4
| 0.08
0.05
|
| (b) Site supervision by resident site staff employed by the consultants
| Professional
Technical
| 12
23
| 40
16 | 1.7
1.7
| 1.28
0.82
______
|
| Total consultants' staff costs
| 2.23
|
126DS - Sham Tseng sewerage and sewage treatment and disposal facilities
Breakdown of estimates for consultants' fees
|
Consultants' staff costs
| | Estimated
man
months
| Average
MPS
salary
point
| Multiplier
factor
| Estimated
fee
($ million)
|
|---|
|
(a) Consultants fees for construction stage
| Professional
Technical
| 9
12
| 40
16
| 2.4
2.4
| 1.36
0.61
|
|
(b) Site supervision by resident site staff employed by the consultants
| Professional
Technical
| 120
670
| 40
16
| 1.7
1.7
| 12.81
23.93
______
|
Total consultants' staff costs
| 38.71
|
* MPS = Master Pay Scale
Notes
1. A multiplier of 2.4 is applied to the average MPS point to arrive at the full staff cost including the consultants' overheads and profit, as the staff will be employed in the consultants' offices. A multiplier factor of 1.7 is applied in the case of site staff supplied by the consultants. (At 1.4.1998, MPS pt. 40 = $62,780 p.m. and MPS pt. 16 = $21,010 p.m.).
2. The consultants fees for construction stage are based on the lump sum fees calculated in accordance with the consultancy agreement the Director of Drainage Services has with the consultants undertaking the design and construction of the project. The costs of resident site staff are based on estimates prepared by the Director of Drainage Services. We will only know the actual man months and actual costs when we have completed the construction works.
1In August 1990, the Administration introduced changes to the system of the Public Works Programme. Category AB projects under the previous system were classified as Category B projects under the new system.
