Pipe-laying

Design and Construction of Collections system

Contractor: jica KOLON GLOBAL CORPORATION, KOREA
Contract Cost: YEN MILLION 3,698
RUPEES MILLION 3,451
Start Date: 26th November 2013
Finish Date: 31st October 2018

The contract package number 02, involves the design and construction of a wastewater collection system including manhole type sewage pumping stations and the procurement and delivery of specialized sewer maintenance vehicles and equipment.

The work includes trunk sewers, branch sewers and service connections sewers up to terminal connection points named Interceptor Chambers (IC) located at each property within the proposed sewer service area. Several manholes will be needed to ensure smooth flow of sewer along the pipelines.

Existing treatment plants at hotels, industry and at two hospitals (Kandy General and Peradeniya Teaching Hospitals) are presumed to be maintained to provide pre-treatment before discharging to the collection system. Given below are the details of pipes and manholes to be constructed under this contract.

Sewer Type Length (km)
Trunk Sewer 9.1
Branch Sewer 76.8
Service Sewer 146.2
Force Main 3.2

Pipe laying details by Road Authority (Trunk & Branch Only)

Road Authority No of Roads Length (Km) No. of Manholes
Road Development Authority (RDA) 22 21 459
Provincial Road Development Authority (PRDA) 7 6 189
Kandy Municipal Council (KMC) 169 53 1864
University 5 2 50
Other 29 6.7 227

Piping Lengths

Branch Sewer

Location Length (m)
D S Senanayaka Mawatha 826
Hill Street 54
Sirimawao Bandaranayake Mawatha 2568
SWRD Bandaranayake Mawatha 346
Thilak Rathnayake Mawatha 423
Yatinuwara Veediya 425
Colombo Street 435
Cross Street 177
Sangaraja Mawatha 716
Baladaksa Mawatha 87
William Gopollawa Road394 394
Bodiyangana Mawatha 257
Sarasavi Uyana Road 202
Kotugodella Veediya 124
Kumaea Veediya 93
Lamagaraya Road 126
Wadugodapattiya Veediya 166
Baladaksa Mawatha 149
Sirimawo Banadaranayaka Mawatha 150
Total 7718

Trunk Sewer

Location Length (m)
Peradeniya Road 60
D S Senanayaka Mawatha 289
Wewsripitiya 41
Hill Street 81
Sirimawo Banadaranayaka Mawatha 775
H B Udurawana Mawatha 108
Heerassagala Junction 50
Mosque Road 270
Sirimawo Banadaranayaka Mawatha 897
Yatinuwara Veediya 140
SWRD Bandaranayake Mawatha 90
Total 2801

Service Area & Pipe Network

service-area

Pipe laying methods

  • Open Cut

Open cut trench excavation is the traditional and most popular method for sewer pipe construction. Open cut trench excavation consists of excavating a trench for the manual installation of each piece of pipe.  This method is usually the least expensive method if the pipe is located under non‐pavement areas. The open cut trench method involves excavating down to required level and lay the pipes and then backfilled.

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  • Trenchless

It is a worldwide trend today to adopt the trenchless methods rather than the open trenching method. Especially in urban areas where the open trenching causes disruptions to the traffic and affects normal operations of existing underground utilities. Such public nuisances are not tolerated by the people, even for public works construction which will surely result in a better living for themselves. As a solution to minimize inconveniencing the public due to pipeline construction works, this high-tech construction method is used. Trenchless method uses a special type of tunneling machine which is being remotely controlled from the operation section located outside in a large pit. The tunneling machines are located in the driving pit. Pipes are pushed under the ground with the help of the tunneling machine. The crushed materials due to the excavation works of the front head of tunneling machine, are transported to the outside through a discharging line. The crushed material are divided into slurry and soils by the treatment equipment on the surface.

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