No_7_July_1968 — Page 39

for extension of the works to cope with the increased load are in hand.

Six digestion tanks are provided and they are constructed in reinforc- ed concrete with the roof ring beam in prestressed post-tensioned con- crete. The tanks are of 70 ft. dia- meter, each having a capacity of 885,000 gallons.

The sludge in the digestion tank is to be heated by the engine cooling water from the compressor house and each tank is to be installed with four Heatamix combined gas lift sludge heaters and circulators to keep the sludge in the digestion tanks to a tem- perature range of 110°F-120°F.

As the digestion tanks are of fix- ed roof type, gas is fed into a 661⁄2 ft. x 47 ft. high adjacent fixed gas- holder having a capacity of 120,000 cu. ft. at a pressure of 12 in. w.g. (g) Compressor house

There is no economic necessity for the generation of electricity at the works as the power required is main- ly for the diffused air plant. Direct driven compressors using dual fuel compressors are installed to deliver air either at 71⁄2 p.s.i. into a 24 in. air main feeding to the west works or at 6 p.s.i. into a 54 in. main delivering Provision is also to the east works.

made in the new compressor house to take two existing compressor sets from the west works compressor house which would be put out of use.

(h) Construction aspects

Site clearance and bulk excavation for all the main treatment units and pipelines were carried out under an earlier contract (site preparation). Un- der this contract a drainage system to take surface water from all sites was built and this greatly reduced problems of drainage of rainwater in subsequent contracts.

The ground was generally firm sandy clay and no foundation pro- blems existed.

In all the main contracts. phasing of construction of the various com- ponents of each contract was of prime importance to suit site requirements, supply of pipework and machinery, and progress of other contracts. The contractors' programme and organiza- tion were therefore subject to close study and surveillance by the Public Works Department.

Close supervision on control of concrete mixing was kept to ensure a consistently high quality concrete. The sequence of concreting and form and position of construction joints are subject to specified requirements and the resident engineer's approval. (i) Integration of east and west works

When the new works (east works) are completed and commissioned, both this and the existing works (west works) will be combined to form an integrated works with common pumping station for crude sludge and drainage, same source of air supply. and common outlet for final effluent and digested sludge.

Far East BUILDER, July 1968.

A.

CONTRACTORS

Description of Works

Contractor

Stage of Progress

PUMPING STATIONS,

RISING MAINS, GRAVITY SEWERS.

Pumping machinery (for Brad- Allen Gwynnes Pumps Completed dell Road & Bartley Road pump- Ltd. Agent: The Bor- ing stations)

Site preparation for Road pumping station Braddell Road pumping station

Amount in $$

498,000

neo Co. Ltd.

Supply of steel sheet piles (for The British Steel Pil- Completed Braddel Road pumping station, ing Co. Agent: Sime

159,000

Darby & Co. Ltd. Braddell N.C. Senan & Sons

Completed

474,000

Paul Y Construction Completed & Co. Ltd.

Commissioned

1,834,000

-do-

564,000

Completed

519,000

Completed &

541,000

Commissioned

· Swee Construction & Transport Co.

-do-

199,000

Lian Hup Han

-do-.

1,242,000

Swee Construction & Transport Co.

843,000

42,000

Bartley Road pumping station Sum Mun Kum Supply and delivery of steel Hume Industries (F.E.) pipes and specials (for rising Ltd. mains No. 1 & No. 2) Rising main No. 1

Rising main No. 2

Gravity sewer No. 1 Gravity sewer No. 2

Supply and delivery of C.I. pipe work (for Braddell Road & Bart ley Road pumping stations & Kim Chuan east works) Switchgear

Cabling (for Braddell Road & Bartley Road pumping stations)

B. TREATMENT WORKS

Sum Mun Kum

Kwong Soon Wing Kee Completed Engineering Works Ltd.

I

|

Guthrie & Co. (S) Ltd.

R.E. Morris & Co. Ltd.

Completed

-op-

438,000

60,000

Site preparation for Kim Chuar Swee Construction & Completed east works

970,000

Transport Co.

Sewage treatment units

Woh Hup Ltd.

Running

3,601,000

Supply and installation of aera Alliance (M) Engineer- Running tion equipment

1,111,000

ing Co. Ltd.

Supply of C.I. pipework

Kwong Soon Wing Kee Completed Engineering Works

514,000

Sludge scraping mechanisms Compressor house machinery

Guthrie & Co. (S'pore); Running

334,000

Harrisons Lister

Running

1,430,000

Engineering Ltd.

Compressor house & administra Lee Kim Tah & Co. Running tion building

1,288,000

Sludge digestion tanks & wash- Union Construction Co. Running water tower

2,876,000

Supply and delivery of C.I. pipe- Kwong Soon Wing Kee Running

218,000

work

Heatamix units

Engineering Works

Guthrie & Co. (S'pore) | Running Ltd.

1,000,000

R.E. Morris & Co. Ltd. Running

240,000

C. EFFLUENT OUTFALL AND

SLUDGE MAINS

Preparatory works for effluent Hup Poh & Co. outfall

Completed

58,000

Supply and delivery of 18 in. & Hume Industries (F.E.) 51 in. dia. steel pipes (for Con- Ltd.

-do-

674,000

tract No. 3)

Effluent outfall (part)

Lian Hup Han

do

846,000

Sludge mains (part)

Supply and delivery of 18 in Hume Industries (F.E.) and 60 in. dia, steel pipes (for Ltd. Contract No. 5)

-do-

363,000

Effluent outfall (part) Sludge mains (part)

Swee Construction & Transport Co.

-do-

998,000

In-

-do-

270,000

Cabling

Supply and delivery of 45 in. Asia Engineering dia. steel pipes and specials dustries Ltd. (for Contract No. 7) Effluent outfall (part)

Sludge mains (part)

Swee Construction & Running Transport Co.

374,000

Swee Construction & Completed Transport Co.

164,000

S $24,742,000

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