NEWater
Encyclopedia
Brand
The American Marketing Association defines a brand as a "Name, term, design, symbol, or any other feature that identifies one seller's good or service as distinct from those of other sellers."...
given to reclaimed water
Reclaimed water
Reclaimed water or recycled water, is former wastewater that is treated to remove solids and certain impurities, and used in sustainable landscaping irrigation or to recharge groundwater aquifers...
produced by Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
's Public Utilities Board
Public Utilities Board
The Public Utilities Board is a statutory board of the Ministry of the Environment and Water Resources under the Government of Singapore....
. More specifically, it is treated wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
(sewage) that has been purified using dual-membrane
Membrane technology
The membrane technology covers all process engineering measures for the transport of substances between two fractions with the help of permeable membranes...
(via microfiltration
Microfiltration
Microfiltration is a membrane technical filtration process which removes contaminants from a fluid by passage through a microporous membrane. A typical microfiltration membrane pore size range is 0.1 to 10 micrometres...
and reverse osmosis
Reverse osmosis
Reverse osmosis is a membrane technical filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and...
) and ultraviolet technologies, in addition to conventional water treatment processes. The water is potable and is consumed by humans, but is mostly used for industry requiring high purity water.
History
Water recycling in Singapore began in 1974 but the experimental treatment plant was closed a year later due to cost and reliability issues.The Singapore Water Reclamation Study (NEWater Study) was initiated in 1998 by the Public Utilities Board
Public Utilities Board
The Public Utilities Board is a statutory board of the Ministry of the Environment and Water Resources under the Government of Singapore....
(PUB) and the Ministry of the Environment and Water Resources (MEWR). The aim of this study was to determine if NEWater was a viable source of raw water for Singapore's needs. NEWater and desalination
Desalination
Desalination, desalinization, or desalinisation refers to any of several processes that remove some amount of salt and other minerals from saline water...
were explored as means to reduce reliance on water imported from Malaysia, which has been a source of friction over the years. Also, while the Malaysian government is bound by two treaties to sell Singapore water until 2011 and 2061, it is under no obligation to do so after these dates.
In 2001, PUB began an effort to increase water supplies for non-potable use. Using NEWater for these applications would reduce the demand on the reservoirs for potable water.
Production
Singapore has a total of five operational NEWater factories, at Bedok, Kranji, Seletar, Ulu Pandan and a newly opened plant at Changi. The first two were commissioned at the end of 2002, the Seletar plant in February 2004, and the Ulu Pandan plant on March, 2007. For educational purposes, there is a Visitor Centre located within the NEWater factory in Bedok, near the Singapore Expo Tanah Merah MRT StationTanah Merah MRT Station
Tanah Merah MRT Station ' is an above-ground Mass Rapid Transit station located in the heart of Tanah Merah, Singapore.The station is part of the East West Line and is between Simei and Bedok and is an interchange for trains going to Changi Airport and Expo...
. Entrance into the Visitor Centre is free.
Process
NEWater is the product from a multiple barrier water reclamation process:- The first barrier is the conventional wastewater treatment process whereby the used water is treated in the Water Reclamation Plants.
- The second barrier, and first stage of the NEWater production process, uses microfiltrationMicrofiltrationMicrofiltration is a membrane technical filtration process which removes contaminants from a fluid by passage through a microporous membrane. A typical microfiltration membrane pore size range is 0.1 to 10 micrometres...
/ultrafiltrationUltrafiltrationUltrafiltration is a variety of membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane...
to filter out suspended solids, colloidal particles, disease-causing bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, some viruses and protozoan cystsMicrobial cystA microbial cyst is a resting or dormant stage of a microorganism, usually a bacterium or a protist, that helps the organism to survive in unfavorable environmental conditions. It can be thought of as a state of suspended animation in which the metabolic processes of the cell are slowed down and...
. The filtered water that goes through the membrane contains only dissolved salts and organic molecules.
- The third barrier, and second stage of the NEWater production process, utilizes reverse osmosisReverse osmosisReverse osmosis is a membrane technical filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and...
(RO). In RO, a semi-permeable membrane filters out undesirable contaminants such as bacteria, viruses, heavy metalsHeavy metalsA heavy metal is a member of a loosely-defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight,...
, nitrateNitrateThe nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...
, chlorideChlorideThe chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
, sulphate, disinfection by-products, aromatic hydrocarbons, and pesticides that cannot pass through the membrane. Hence, NEWater is free from viruses and bacteria and contains very low levels of salts and organic matterOrganic matterOrganic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...
. At this stage, the water is already of potable quality.
- The fourth barrier, and third stage of the NEWater production process, acts as safety precaution. UVUltravioletUltraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
disinfection is used to ensure that all organisms are inactivated and the purity of the product water guaranteed. With the addition of some alkaline chemicals to restore the pH balance, the NEWater is ready for use.
Applications
At present, the total capacity of the three factories is about 20 million US gallons per day (75,700 m³/day). About 6% of this is used for indirect potable use, which contributes 1% of Singapore's potable water requirements of 380 million US gallons per day (13 m³/s). The rest of the water is used at wafer fabricationWafer fabrication
Wafer fabrication is a procedure composed of many repeated sequential processes to produce complete electrical or photonic circuits. Examples include production of radio frequency amplifiers, LEDs, optical computer components, and CPUs for computers...
plants and other non-potable applications in industries in Woodlands
Woodlands, Singapore
Woodlands, or the Woodlands New Town , is a suburban town in northern Singapore, part of the North West Community Development Council district...
, Tampines
Tampines
Tampines is the largest residential area in the city-state of Singapore and is located in the East Region of the main island. The town is so named because in the 1900s a large forest of Tampines trees were there....
, Pasir Ris
Pasir Ris
Pasir Ris is primarily a residential area in Singapore comprising many high-rise residential dwelling blocks, mostly public housing built by the Housing and Development Board in Pasir Ris New Town. The town is located in the eastern part of Singapore....
, and Ang Mo Kio
Ang Mo Kio
Ang Mo Kio（宏茂桥） is a heartland new town located in north central Singapore, and is generally within the North-East Region. It contains many of the common features of the island nation's neighbourhoods, e.g. hawker centres, wet markets and HDB housing blocks. Singapore's Prime Minister, Lee Hsien...
.
Potability
The quality of NEWater consistently exceeds the requirements set by USEPAUnited States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
and WHO
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
guidelines and is, in fact, cleaner than the other sources of Singapore's water.
Plans are under way to increase the amount of NEWater in indirect potable use up to 3.5% by 2011.