Bangkok sewerage flows,
ThailandBangkok has implemented a central system of
wastewater collection and treatment, commencing in the early 1990s.
This diverts sewage flows from the network of klongs
(canals) within the urban area and the River Chao Phya to treatment
plants, thus significantly reducing pollution of the waterways.
Succeeding phases have extended the coverage of the sewer and
treatment systems.
Stage 4 of the Bangkok Wastewater Project provided trunk sewers and
pumping stations to intercept foul sewage flows before they reach
the
klongs, and transport this to a treatment plant forming
part of this Stage. The area covered by Stage 4 is 33km
2
of the densely populated northern areas of Bangkok, with a 2020
population of 532,000. The design dry weather flow is 200Ml/d, with
the interceptor system designed for a maximum capacity of
1,000Ml/d.
The lack of available land and the bisection of the project area by
several major thoroughfares has demanded cutting-edge solutions for
both the collection system and the treatment works. The
multi-storey treatment works utilise sequencing batch reactor (SBR)
technology to minimise the building footprint. Preliminary
treatment and the sludge process stream are similarly housed in a
multi-storey structure. The collection system includes 30km of
mini-tunnelled sewers of diameters up to 2,300mm, mostly located
under major highways or
klongs. The project includes two
major components, the wastewater collection system and the
wastewater treatment facilities.
Mott MacDonald was the lead consultant of a joint venture involving
three consultants. The JV supervised the turnkey design and
construction of the works, including:
- Contract management
- Review of contractor’s design proposals
- Examination and approval of the contractor’s programme of
work
- Construction supervision (wastewater collector systems and the
wastewater treatment plants)
- Material, equipment, facility tests (including inspection upon
manufacture, prior to shipment)
- Supervision of Operation & Maintenance for the initial
12-month post commissioning period.
