Challenge

Due to continuous growth in population and industry, wastewater management and reclamation is an important topic for Singapore to ensure a future sustainable water supply. Although water is precious for this city-state, so is space. When Siemens Water Technologies was selected by Sembcorp plant design and operations firm to supply equipment and engineering for the membrane filtration portion of the Sembcorp NEWater Plant, space requirements and power consumption were key requirements.

Weight of the system and foot print were critical design criteria, since the membrane filtration system and RO system would be built on the roof top of the existing Changi Water Reclamation Plant. Also, the plant’s power consumption was important to ensure the lowest life-cycle costs for operating the plant. The Sembcorp NEWater Plant will be the second largest wastewater reclamation plant in the world when it produces its full capacity by mid-2010.

Solution

The MEMCOR® CP membrane system in the Sembcorp NEWater Plant uses light weight membranes (around 20 lb), which deliver more membrane surface area per unit floor than many other membranes. This reduces footprint of the plant, which is beneficial for reducing the load on area power infrastructure and the roof. The membrane filtration system at the Sembcorp NEWater Plant is designed to produce the least backwash wastewater compared to the available membrane filtration systems in the market. The Siemens technology recovers 93% of its backwash, resulting in generation of 10 MLD less wastewater.

In addition to greater membrane surface area and greater backwash recovery, the membrane filtration system optimizes power consumption as it does not require backwash pumps. The backwash operation is air assisted which provides two distinct advantages: savings in capital expenditures and operating cost for a backwash pump. Furthermore, the membrane filtration system does not require chemical coagulant dosing of the feed water, which helps save on chemical costs and also helps in protecting the environment. The membranes run at low trans-membrane-pressure across the membrane which requires less pressure to filter the water. This helps in reducing power consumption and further assists in keeping the membrane filtration system “green”.

Results

The Sembcorp NEWater Plant DBOO (Design, Build, Own, Operate) project is best-in-class from a long-term lifecycle cost perspective. It stresses sustainability, anticipates future costs, and aims to reduce these not only now but in the future.

• Tangible and intangible savings on waste neutralization and waste disposal costs are achieved and make the solution environmentally friendly.
• Power consumption is optimized by low trans-membrane-pressure and the
  absence of backwash pumps.
• The average production capacity of the MEMCOR®  filtrate flow is 288,000 m³/day with a peak value of 316,000 m³/day.
• Low power use minimizes energy costs.
• Reliability ensures lowest possible maintenance costs.
• Consistent high water quality to maximize operating life of downstream
  treatment equipment (reverse osmosis membranes).

View a video for a similar NeWater plant case study: