Singapore Water Anonymous: Disinfection by Candle Light

I'm not sure whether the light from a candle is sufficient to disinfect any significant amount of water via this new photocatalyst, but the implications of such a material could revolutionise household water filtration.

Today, many people have simple carbon-based water filters in their homes. These are fairly effective against heavy metals, certain chemicals, and some microorganisms. To be sure that your water is completely free from bacteria and viruses, however, reverse osmosis or UV disinfection are necessary. But these systems tend to be bulky, energy intensive, and expensive.

A photocatalyst that works under normal visible light would mean that you could just leave a jug of water with the filter submerged on a table in the open, and voila, bacteria-free water! What's more, the photocatalyst is said to be able to retain its disinfecting abilities for up to 24 hours after being exposed to light. So if you've left said jug of water exposed to light for a short while, you can stuff it in the fridge and it'll continue the disinfection process.

That said, I'm not convinced that all this purification is truly necessary. Perhaps in certain rural or developing countries where water is sourced directly from rivers and wells, which could be contaminated. Or in old houses where water pipes may not have been used in a long time, resulting in the growth of bacteria. But for the most part, if those glowing water quality reports from our utilities are to be believed, I'm not sure what else our small little home systems hope to achieve. If you must, do at least try to get a sample of the water from your tap analysed by a certified laboratory before investing heavily in some expensive water treatment system that the friendly saleslady insists is vital for your health.