Power generation consumes huge amounts of water. In FY07/08, we used slightly below two million cubic metres of water.  This is a 9% reduction from FY06/07’s water use (2,186,600 cubic metres) at the plant. Our water consumption at the office headquarters is reflected separately.

Diagram 7.8: Water consumption reduction at the plant

With regard to water self-sufficiency, we now rely less on freshwater since our seawater desalination plant started in mid-2007 with about 20% of water use coming from desalinated water in FY07/08. In 2008, freshwater use comprised only 10% of water consumed for operations.

With our new desalination plant, PowerSeraya contributed to the sustainable development of the country by achieving water sufficiency - one of the goals set out in the Singapore Green Plan 2012.

The plant, which was named ‘Desalination Plant of the Year’ at the Global Water Awards 2008, also gave the company the following economic benefits:

• Reduction in cost of water by 30%
• By co-locating the desalination plant with the power station, PowerSeraya saved up to 25% of capital costs of infrastructure alone. This links back to the sustainable business strategy
• The integration of the operations of the desalination plant and the power generating plants enables PowerSeraya to produce steam and cooling water which can be sold to neighbouring companies

Wastewater discharge
Power generation produces wastewater which is discharged into the sea. This water undergoes stringent quality checks for heavy metals, biological oxygen demand (BOD) and chemical oxygen demand (COD) to determine whether it has significant effect on fish or aquatic plants. The wastewater samples are taken bi-yearly and sent to an accredited laboratory for tests. For the period FY06/07 to FY07/08, the wastewater discharge was in full compliance with the regulations in the Environmental Protection and Management Act.

The BOD and COD tests measure the relative oxygen depletion effect of a waste contaminant. In FY06/07 and FY07/08, the BOD tests in the treated wastewater were less than 20mg/l and were well within regulatory limits of 50mg/l. For COD, the range was consistently below 50mg/l, well below the regulatory limits of 100mg/l.

Other significant substances contained in the trade effluent include Total Suspended Solids (TSS), Total Metals and Oil and Grease. These substances are also monitored periodically to ensure that they are in compliance with regulatory limits.