Using Membranes to Combat Water Shortages
Membrane separation technology for seawater desalination and wastewater reclamation
The global threat of water scarcity
General Manager, Water Treatment Division, Toray Industries, Inc.
Although the earth is a planet of water, only 0.01% of the planet’s water is fresh water suitable for human consumption. Population and economic growth have increased the demand for water, while rapidly advancing climate change is causing severe drought and water shortages in previously unaffected regions. For example, in recent years, the United States has experienced severe droughts from the West Coast all the way to the Midwest, resulting in water restrictions and bringing attention to previously unused water resources such as treated wastewater.
Seawater desalination and wastewater reclamation to combat water scarcity
Seawater desalination and wastewater reclamation offer solutions to the problem of water scarcity. These solutions are based on membrane separation technology. The Toray Group has been building expertise in this area for almost half a century.
Membrane separation technology enables the filtering of suspended solids and salts in an aqueous solution, by selectively using various membranes. The Group manufactures every type of membrane used for seawater desalination and reuse of treated wastewater, supplying a global customer base with membrane products such as ROMEMBRA™ membrane element for reverse osmosis (RO) and nanofiltration (NF), TORAYFIL™ hollow fiber membrane modules for ultrafiltration (UF) and microfiltration (MF), and MEMBRAY™ immersion-type membrane modules for membrane bioreactor (MBR) systems. The Group is also establishing manufacturing, sales, and R&D operations worldwide.
In a seawater desalination plant, various membrane technologies such as UF (pretreatment) and RO (desalination) are applied to produce drinkable water from seawater. In a wastewater reclamation plant, MBR and RO technologies are commonly used to treat sewage water and plant wastewater.
The seawater reverse osmosis desalination (SWRO) process is widely used due to its relatively low energy consumption. By Toray’s calculations, the SWRO process emits one-fifth the CO2 of the conventional evaporation desalination process.
Worldwide applications for Toray Group water treatment membranes
- How membranes filter particles
The pores in the multiporous film water treatment membrane are one nanometer in diameter (one-millionths of a millimeter). The pores filter out salt and impurities from the seawater.
How an RO membrane works
Toray water treatment membranes helping to supply drinking water for Singapore
Singapore has a very small land mass with minimal sources of fresh water. Traditionally, it has had to import its household water. PUB, its national water agency, sought to address the situation by launching a project to use membrane separation technology to desalinate seawater using water treatment membranes and purify wastewater to secure needed household and industrial water. Toray’s RO membranes are currently used for about 70% of the project, which involves a seawater desalination plant that can process more than 440,000 m3 of seawater per day, and a wastewater treatment plant that can purify 230,000 m3 of wastewater per day. Singapore plans to further expand the project to increase its internally available water resources.
The Toray Group will continue to leverage its extensive experience to further develop and supply its membrane separation technology in order to address global water scarcity.
- Example of seawater desalination facility Toray supplied RO membranes to Asia’s first seawater desalination plant with a capacity of 100,000 tons per day, built in 2005.
- Example of wastewater treatment and reuse facility Toray supplied RO membranes for the largest-class wastewater treatment and reuse plant in East Asia (second largest in the world).
The NEWater plant at Changi produces enough water to meet 30% of Singapore’s total water demand. The plant uses Toray’s RO membranes to produce high-quality water using less energy. Seawater desalination and reuse of treated wastewater based on membrane technology offer a solution to water scarcity worldwide. Toray Asia will continue to work closely with the Toray Singapore Water Research Center to address water issues through the application of membrane technology.
Regional Manager, Toray Asia Pte. Ltd.
TopicSupplying mobile water treatment units to address water scarcity in Bangladesh
The Toray Group was contracted to supply 30 mobile water treatment units to Bangladesh, under an Official Development Assistance (ODA) grant-in-aid program of the Ministry of Foreign Affairs of Japan to address natural disasters from climate change. These mobile units use UF and RO membranes manufactured by the Toray Group. Each one can supply enough water for up to 300 to 500 people per day, using river water and well water. The mobile units are supplying drinking and household water to Bangladesh citizens who face a shortage of safe water.