By Anthony Tan
I refer to the commentary “Singapore water cost 10 times more than Hong Kong but average consumption only 30% less” on your site.
While I agree with the author view that price of water is considerably higher than in certain countries. As an environmental engineer, I, however, disagree with the way the author makes his argument. Water though is universally similar as H2O, two hydrogens atoms, and one oxygen atom. The access to water is not. Some countries just received more water than others.
Our limited size means there is a limit to how much free water we received from the sky. And Even with imported water from Johor, there is just not enough to meet our water demand. Hence we require NEWater and desalination, which are very energy intensive. Let me digress here to water chemistry. Osmosis is the diffusion of water from a higher concentration gradient to a lower concentration gradient and it occurs naturally all around us. In our body, in plants, in the natural system. To produce clean drinking water, though requires the usage of reverse osmosis – which as the term suggest ‘reverse’ this natural flow of water. And it is this reverse osmosis process that is very energy intensive. In the context of daily life, this will be akin to walking against the crowd (reverse osmosis) versus walking with the crowd (osmosis).
Finally, the clean drinking water has to be channeled into our home. This is done through underground pipes buried deep island wide, and up against gravity into our home. This involves the laying of pipes and mechanical pump. Try throwing a ball up into the sky. How high did you throw? 5m? 10m? What about the type of ball you threw? A tennis ball? Basketball? Or a bowling ball? Now, how high is your HDB flat? 12 stories, 20 stories or even further up? The amount of energy requires to pump the water all the way up to the top floor is enormous. The sheer quantity and height. A mechanical pump does all these work for us. And just like ourselves, our water infrastructure is aging and requires periodical health screening (maintenance) and operation (upgrading).
An increase in price definitely left a bitter aftertaste for us, but we must view it with perspective. Many of us have no qualm buying a bottle of drinking water from the supermarket or convenient store. The last I check a bottle of 600ml Dasani water cost around a dollar. The price of tap water in Singapore cost $1.17 per cubic meter. That is 1000 liters of water, a 3 order of magnitude different.
Yes, there are other countries that have cheaper water. But there are not many countries in this World that have what we have. The convenience of clean drinking water flowing anytime out of our tap. Frankly speaking, the current price of water is really affordable, for such an important necessity.
Below are the answers by Anthony in response to the editor’s questions about the common complaints from engineers in regards to the water treatment in Singapore.
1) The water is not pre-treated, which damages the expensive osmosis membrane.
I can’t ascertain much, without getting more facts about the water quality and pre-treatment first. But from a hydrological stand point, pre-treatment is definitely preferred to remove off larger particles and reduce the chances of membrane fouling (damages).
2) Why are the water for the public lines treated to a drinkable level, given that the water used by most consumers are not for drinking purposes?