By Gloria Seow, Education Group Chairperson
For the first time ever, there were no kids at this Education Group visit to Singapore's National Water Agency PUB’s NEWater Visitor Centre in Changi. Instead, adult NSS members were treated to an eye-opening, behind-the-scenes tour of Singapore’s water reclamation capabilities on 19 July 2014.
A volunteer PUB guide took us through the paces. She first explained that NEWater is high-grade reclaimed water produced from treated used water and further purified using advanced membrane technologies. We found ourselves wandering around a cavernous exhibition area, full of fancy features that fed us facts like how much water an average person uses per day (152 litres) as well as tips to reduce water consumption. Dispensed advice included using the washing machine only on a full load, collecting rinse water from washers for flushing and mopping, and cutting one’s shower time by one minute to save nine litres of blue gold.
|An exhibition area dispensed practical water saving tips in digestible graphics.|
The guide then introduced us to the Deep Tunnel Sewerage System (DTSS) that Singapore has constructed for used water collection, treatment, reclamation and disposal. It comprises 48 km of deep tunnel sewer, up to 6 m in diameter and 50 m underground. The DTSS currently runs from Kranji to Changi. It intercepts the flows of existing gravity sewers via link sewers, upstream of pumping installations. The DTSS then channels the flows by gravity to two water reclamation plants (WRPs) located in the coastal areas of Kranji and Changi. At present, NEWater meets up to 30% of Singapore’s water needs. DTSS Phase 2 is currently in the works. It will terminate at the future Tuas WRP, and by 2060 will increase NEWater supply three fold to meet up to 55% of future water demand.
|We learned about Singapore’s Deep Tunnel Sewerage System that channels used water by gravity towards coastal water reclamation plants in Kranji and Changi.|
Finally, we came to the pièce de résistance of the programme – a tour of the adjoining NEWater factory. We walked along a two-storey high glass tunnel constructed through part of the factory. The tunnel held educational displays that made reference to the factory proper. Not surprisingly, the entire water reclamation operation was automated. There was nobody on the ‘factory floor’, only workers in a control room monitoring the proceedings.
|In the NEWater factory tour, we found out that microfiltration is one of the key steps in producing reclaimed water.|
Nature’s water cycle has been recycling used water since the beginning of time. Similarly, the NEWater factory has interconnected pipes everywhere, performing water reclamation functions such as ultra-filtration, micro-filtration and reverse osmosis (RO) of used water. In RO, a semi-permeable membrane allows only miniscule water molecules to pass through, trapping larger unwanted particles such as bacteria, viruses, heavy metals, salts and pesticides. UV disinfection of RO water is then performed as an extra safeguard. Finally, alkaline chemicals are added to obtain the desired pH balance. The resulting NEWater is purported to be ultra-clean and safe to drink, having passed more than 110,000 scientific tests and surpassed World Health Organisation requirements.
|We had cross-sectional close-up views of the membranes used in reverse osmosis.|
NEWater is primarily for non-potable industrial uses such as wafer fabrication, power generation and air conditioning in commercial and institutional buildings. This frees up potable water (ie. water collected from reservoirs, piped from Malaysia or obtained via desalination) for domestic consumption. During dry periods, NEWater is added in tiny quantities to our reservoirs and blended with raw water. This blended water then goes through the usual waterworks treatment before it becomes tap water.
Indeed, it was good to learn through this visit that Singapore has a secure and sustainable water supply that will meet both current and future needs.