Supplement: Singapore River - a Water Source?

Dear Readers,

This is apart from my 10 blog posts for LA ACE. This is just a supplement to this blog (: Singapore River is a renowned river and has been with Singapore for much of its history. Take a look at this for more details!

Is the Singapore River a source of water for us today?

No, the Singapore River is not a source of water for us today but will be one in the near future. The Singapore River has already been dammed to form the Marina Reservoir. When all the seawater has been drained off by 2010 or 2011, it will become the largest water catchment area which will cater to 10 per cent of the current water demand in Singapore.

If so, how? If not, what is/are our water source(s)? [Use diagrams]

The four major water sources which Singapore relies on today include reservoirs, NEWater, imported water from Malaysia (expiring in 2061) as well as desalination.

Reservoirs

After the collection of rainwater, it is aerated while it flows over a series of steps to help oxygenation.

In the sedimentation tank larger particles are allowed to settle. Aluminium sulfate is used to make small, suspended particles of clay coagulate. The water is filtered through layers of sand and gravel to make sure all solids are removed. The filter bed also contains carbon slurry to remove odours and any odd tastes. The water is disinfected by adding chlorine (chlorination). The chlorine kills all the bacteria in the water. Finally, this clean water is stored in reservoirs, where it is pumped into the water mains for use.

NEWater

The NEWater technology uses Microfiltration, Reverse Osmosis and Ultra-violet light disinfection in a simple three-stage treatment process.

The first process is called Microfiltration. The treated used water is passed through fibres that work as microscopic filters. It also removes bacteria and protozoa.

In the next process, the microfiltration filtrate undergoes Reverse Osmosis. This removes inorganics like heavy metals, nitrate, chloride, sulphate etc, and organics such as disinfection by-products, aromatic hydrocarbons, pesticides etc present in the microfiltration filtrate. The RO membrane also removes viruses.

Finally, ultra-violet disinfection is a safety back-up to remove any bacteria or viruses should the reverse osmosis membrane be compromised and the viruses and bacteria go through the reverse osmosis process.

Purchased water from Malaysia

Singapore currently has a contract with Malaysia, where the latter will supply us with drinking water. However, this contract will end in the year 2061.

Desalination

Desalination is a treatment process that removes dissolved salts from seawater. The two main processes are the distillation and membrane processes. In the distillation process, a variety of methods are used to evaporate seawater, condense the vapour formed and obtain distilled water that is essentially free from salts. In the membrane process such as the reverse osmosis process, pre-treated seawater is pumped at high pressure through a semi-permeable membrane that separates the water from the dissolved salts.

What do you think is the best water source?

I think that the best water source is through desalination. Among all the water found on the surface of the Earth, 97% is sea water. Since the technology on desalination of water is getting more economical and affordable, more effort should be placed on converting this abundant seawater into drinkable freshwater.

[Optional] Propose new, alternative water sources.

Singapore has numerous flats in many estates spread across the entire island. If on every flat, there is a huge water container built, where great amounts of water in every part of the island can be collected whenever there is rain. This water can then be pumped to the nearest reservoir in or near the estate, where it can undergo necessary treatment before use.

Regards,
Nathan (: