Centralised Wastewater Management System for Miri (Phase 2)
TWELFTH MALAYSIA PLAN PROJECTS
Title :
Centralised Wastewater Management System For Miri City (Phase 2)
Project Background :
Phase 1 of the project covers Central Business District (CBD) of the City which is fully developed and densely populated. The works consist of 3 main components, namely:
- Centralised Sewage Treatment Plant (CSTP) Module 1 (50,000 PE capacity)
- Trunk, Secondary and Tertiary Sewer Network, and
- Property Connections to 40,345 population equivalent (PE).
(Link to Centralised Wastewater Management System for Miri City Phase 1)
This Phase 2 will extend the coverage to Krokop and Piasau areas. The works will consist of 3 main components, namely:
- CSTP Module 2 (50,000 PE capacity)
- Tertiary Sewer Network, and
- Property Connections to 45,000 PE
I. Centralised Sewage Treatment Plant Module 2
The existing Miri Centralised Sewage Treatment Plant is located on a 31.5 acres site adjacent to Tudan Forest Reserve. The site has sufficient land to accommodate 4 modules of sewage treatment facility and an ultimate capacity of 400,000 PE. The first treatment process module was constructed under Phase 1. Under this Phase 2, a second module will be added to this CSTP.
Domestic wastewater (greywater and blackwater) from the kitchens, bathrooms, wash areas and toilets is collected via a sewer reticulation network and channelled to this plant for treatment. The plant treats the domestic wastewater to meet Standard A of the Environmental Quality (Sewage) Regulations, 2009 requirement. The treated effluent shall then be discharged through an outlet drain to Miri River.
II. Sewer Network
The sewer network is designed to flow on gravity. Trunk sewer from CBD of Miri City was completed under Phase 1. The sewer network under this Phase 2 will comprise of only secondary and tertiary sewer. The size of the secondary sewer ranges from 300 mm to 450 mm in diameter. The sewer is either of reinforced concrete or HDPE material. Secondary sewer will be mainly installed by trenchless method using Tunnel Boring Machines. Tertiary sewer is generally of 225 mm in diameter and will be mainly installed using the conventional open-cut method.
The overall length of the sewer network under this Phase 2 is approximately 74 km.
III. Property Connections
Property connection involves re-routing of existing domestic plumbing for the collection of wastewater (i.e. greywater and blackwater) to public sewer networks. Domestic wastewater from within the property boundaries (i.e. houses, shops, institutions or commercial complexes) is collected and channelled via sewer within the property boundary to an inspection chamber outside the property boundary and subsequently to the nearest public sewer. A pumping system may be adopted for properties with limited space or gradient issue. In such cases, electric pumps will be installed in the existing repurposed septic tanks or package plants. Upon completion of the property connection works, the existing unused septic tanks or package plants will be disinfected and decommissioned.
The total number of properties to be connected under this Phase 2 is about 7,500 units with an estimate of 45,000 PE.
