Letter 16017

Reclaimed Water  

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What is "RECLAIMED WATER"? Recently Singapore's government have announced to produce "RECLAIMED WATER" for drinking and general use instead of buying from other sources. Is this water safe for drinking? and how this water was being produce?

Thanks,

Ken Chia
- Singapore

Hi Mr.Chia,

I understand u have concerns with the New water which Singapore is reclaiming from used water.

The process is pretty simple..

Basically water is contaminated with organic and inorganic materials. They may either be Dissolved or suspended.

So the purity of water is expressed in terms or Suspended solids and Dissolved solids.

The treatment steps involves in getting rid of these contaminants. Basically all water sources are contaminated, you cant get pure water from any source. To make water potable it has to go thru various treatment cycle before used by humans.

The normal water you are getting from river or reservoir goes thru the treatment process just like the reclaimed water. Except that few additional treatment has to be done.

The process goes like this ..
The water to be reclaimed is first filtered of suspended solids by passing the water through a series of filters. This may be the primary filtration. After which they are stored in a lagoon and aerated. ie air is passed thru the water to oxidize the organics present in the water and to prohibit the growth of anaerobic bacteria which grows in presence of organics and causes the water to stink (thats why stagnant water stink)... Aeration increases the Dissolved oxygen content in water.. this process is similar to the natural cleansing cycle used by river.. river water while running down the stream absorb lot of oxygen and oxidize all the organics present in them .. the aeration is artificial way of improving the dissolved oxygen content of the water.

After this process .. they are added with cougalants and flocculants to settle very small suspended solids ... or they may go through series or filters .. sand filter etc...

After filtering the solids the water may pass thru carbon filter to remove organic contaminants or directly go for Reverse osmosis ... in this process . the water passes thru a semipermeable membrane .. they call it membrane filter .. u need to apply pressure to pass the water thru the membrane .. this membrane doesn't allow molecules of bigger size to pass thru .. thus it will stop the dissolved solids, organics, bacteria of particular size to not to pass thru the membrane ....

If before the RO, water has Total dissolved solids of 1000 ppm after RO you can expect it to be between 50 - 100 ppm ... this water after RO is free from Bacteria to some extent and less in dissolved contents ... to completely sterilize the water .. you need to either .. chlorinate them .. or ozonate them or .. pass it thru a UV filter ... this is the last step ...

Once these process are done ... the water is cleaned of its suspended solids and dissolved contents .. the water regains its original form and is potable .. can be used for human consumption .... The quality of water you get is just similar to the one which is sold as mineral water. The water is removed of all contaminants which are not good for human. This water is completely safe and I believe is better than the normal water you get from reservoir.

May be you can go to the treatment plant and have a look yourself. The process sequence may vary a little and you can also see how the control the quality of water and the testing used on the water.

What the political community cant provide you .. the scientific community will do ....

Good luck ..

Karthik
- Singapore

Hi Mr Karthik,

Thanks for your reply. As I know the "USED WATER" was from washing, cleaning, flushing etc... Is this true??? The feeling of drinking the water from flushing is not so good...

Thanks,

Ken Chia
- Singapore

Hi Karthik,

I appreciate the information and effort put into the email reply to Mr Chia. The information you provided was rather detailed, and I found it very useful. Do you represent a distilling/treatment plant in Singapore? Or maybe you could help me by directing me to a few creditable web sites to which I can read further into 'New Water'.

More importantly, as you are well versed in this area, I would like to know if you would then recommend that I seriously consider installing water distillers/filters in my home? They range from about S$1200 to S$1390 (non-network marketing products) - a rather hefty sum. Of course, there are much cheaper ones that cost about S$300, for which I am not sure I will pay, as I automatically assume them to have lesser distilling power and features.

Please share your views. Thank you!

Sincerely,

Elaine Ng
- Singapore

Hi All,

Nice to read about the water issues and filtration process of NewWater. Apart from those advise, can anyone highlight what kind of filtration system is sufficient and value for money ? (There are many products with differing technology but what is sufficient to ensure a good healthy water quality for a s'pore home?)

Thanks,

Chia, John
- Singapore

Hi John,

I have explored quite a bit on water purification. The water in Singapore is quite safe to drink straight from the tap. Like what Karthik wrote. The only shortfall is the transport media (water tanks, pipes, etc.)

Regarding New Water, I believe many people is quite concerned about the issue of reuseable water. With the proper treatment it is as clean as from the other source(if you know what's happening at the source)

Water filtration in the home should be done closest to the point where get the actual drinking water. If the pipes in your home are clean, then you can install it near the mains.

There are different types of water of purification for your home. They can vary from a single "cotton" filter to a multi-stage filter that removes 99.99% of any particles. With New Water I think they can filter out particles as small as 0.001 microns. With some home filtration system, they can go up to 0.0001 micron.

They also can cost from S$8.00 to about S$1,300.00 or more depending on what you want to add on. It's up to the individual needs.

Andrew Tay
- Singapore

Hi Elaine, John, Andrew,

Your interaction is interesting. I am not sure if you have chosen any home water treatment system.

These websites are useful for you to choose a good WTS:

www.nsf.org

http://www.nsf.org/Certified/Common/Company.asp?submit4=All+Manufacturers&Program=DWTU

(The more standards from NSF is better)

www.wqa.org (look out for Gold Seal Award, not Member of WQA when you choose your WTS)

Joseph Liang
- Singapore

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