Singapore's Public Utilities Board (PUB) selected a Singaporean company, SingSpring, to develop a private sector, 20-year water supply project, utilizing a build-own-operate (BOO) contractual structure. SingSpring appointed Hydrochem as the EPC contractor for the 136,380 m3/day (36 mgd) reverse osmosis (RO) seawater desalination plant, one of the largest in the world. This is the first project undertaken by the Singapore Government on a Public-Private-Partnership initiative.
Hydrochem in turn awarded a contract to Black & Veatch to provide design, permitting, construction, and commissioning services for the EPC project. In addition, Black & Veatch will provide O&M assistance for the first five years of operation.
Desalination Process Component
The RO system was designed to operate within the following parameters:
- Pretreatment: Chlorination (periodic), combined dissolved air flotation – filtration, dechlorination (as needed), antiscalant addition, pH adjustment, and cartridge filtration.
- Capacity and Train Arrangements: 136,380 m3/day with First Pass (seawater) RO and partial Second Pass (brackish water) RO to remove boron.
- Energy Use: 4.4 kWh/m3, nominal.
- Percent Recovery: 45% in First Pass and 80 – 90% in Second Pass.
- Feedwater TDS: 28,000 to 35,00 mg/l.
- Brine Disposal: Ocean.
Other Key Project Issues
Major technical issues on the project include the seawater acquisition method (comparing open intake to beach filtration), pretreatment (comparing dissolved air floatation – sand filtration to micro- and ultra-filtration membranes), RO membrane selection, complying with challenging finished water quality parameters including a low boron concentration requirement, minimizing energy usage with cutting-edge energy recovery to meet the stringent guaranteed power consumption, post-treatment for disinfection and corrosion control, ocean outfall, and the related pilot program.
3-Dimensional Object Oriented Engineering (OOE) was used extensively to provide detailed modeling on all the structures during the design stage, incorporating civil, structural, mechanical, electrical and building services to identify clashes between structures and services.
The fast-track design was carried out by Black & Veatch in less than 7 months, allowing the construction program to be shortened. The plant was completed in September 2005, three months ahead of schedule.
Safety & Health
Oil and Gas
