Use of recycled water
Published November 24, 2008 | 
Chris from Toronto writes:
Hi there, I am doing a research project on the viability of implementing some rural water saving solutions in the city. The one idea I had was to use rain barrels on top of larger buildings to supply the occupants with their water. I figured that anything we can do to reduce the load on the city reservoirs the better, especially to conserve the electricity that our pumps use. I was wondering if you could give me some input…Aren’t apartment buildings built with an internal reservoir system already that purifies the water and distributes it onsite? If not, do you think it could be practical to just tie into systems that don’t require purifying, like toilets and washing machines? I’d really appreciate your help. Thanks
Hi Chris, thanks for your question.
There are two truths happening right now:
- An increase in population
- A water supply steadily decreasing in availability
As our population goes up, our ideas of housing is changing. In larger cities, more and more condominiums are rising to the sky, housing more people in a smaller area. In smaller cities, new housing developments are severely cutting the land around houses, packing them in closer and closer.
Working in the water treatment section of a municipality, it always amazes me how much water is being treated to tough potable standards, and how little of it is used for potable uses like drinking and cooking. Most of it goes to washing and industrial purposes.
Currently most water is used as a once through application. It goes down the drain and dissapears to the waste water treatment plant, for treatment and release to the environment. But as water becomes more scarce, water will have to be recycled if we would like to continue to use water as we are.
I don’t know the current status of most apartment buildings. However, sustainability projects such as you propose are feasible. The infrastructure on older buildings would be expensive, but it would be relatively cheap to integrate into brand new apartment buildings.
Potable water from the city could still be piped in. However, you would have a tap or taps designated as potable in your apartment, such as the kitchen sink and the bathrooms. Your drinking, cooking and other miscellaneous uses (such as brushing your teeth) would come from these taps. To ensure that the potable water does not get cross contaminated from any other water source, the piping would have to be completely separate from other sources.
Separate from your drinking water, showers, laundry facilities and outside hose bibs could be recycled grey water mixed with rain water collected on the roof. Simple centrifugal separators, filtration and light disinfection (U.V. and/or chlorination) could make this water clean, clear and useful for such washing applications. The water sent to your waste water treatment plant would be a more concentrated form of the contaminants removed.
Using a system like that would mean existing water treatment plants would be able to supply cities far into the future with their potable water needs without the need for further and further expansion.
I hope that gives you a direction for your research project, Chris. If you have any further questions or would like further detail, please do not hesitate to write in again.
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Mercury and Fluoride in Drinking Water
Published November 22, 2008 | Pat from San Diego, California writes:
I am fearful of drinking our tap water, as I have been hearing of the dangers of mercury in our water and its proliferation due to the Bush policies that have encouraged polluters to increase its concentration. But the last straw was when our local county boards started adding fluoride to our water. It was then that I started buying bottled water for all of our drinking needs.
Could you please tell me where I could take my drinking water for testing of these 2 pollutants?
Could you discuss what type of water treatment could be relied upon to remove mercury and fluoride?
I was very hopeful about buying a steam-condensing system and then I read your comments about distilled water (I presume that’s what such a system produces) and now I am fearful of distilled water too.
Hi Pat, thank you for your question.
I’d like to address fluoride first. Fluoride is an interesting chemical and has been the source of much debate among water purveyors and health professionals. While it is considered a toxic chemical in it’s concentrated forms, in trace amounts it is actually beneficial for the health and strength of teeth. Typically, water supplies that do not have a high enough naturally occurring fluoride concentration have been fluoridated to compensate for this. The argument is whether this is needed or not, as some feel there is enough fluoride in tooth paste and food items to provide for the bodies need for trace amounts of fluoride. The trace amounts of fluoride in your water will not harm you. In fact, you should check the label of the bottled water you have been using. Often, bottled water will contain as much or more fluoride as your tap waters.
I understand your concern of mercury. This contaminant is a dangerous one, and no doubt you have heard of Minimata Japan, where Minimata disease was first found, which is mercury poisoning. While mercury in your water supply is something to be concerned about, you should be much more concerned about mercury poisoning in fish.
When mercury enters a water supply, microbes can convert it to an organic form of mercury. Larger animals eat these microbes, and so on and so forth up the food chain in a process called biological magnification. This biological magnification causes a significant amount of mercury to be bound up in the muscle tissue of fish, who do not have the same capacity to remove trace mercury from their systems as mammals do.
Under the United States EPA, municipal water purveyors are required to test for mercury at a regular basis. If they detect a level above 2 parts per billion, they are then required to impliment measures to remove it as well.
Just to let you know, bottled water retailers are under no such regulation and can bottle anything they want.
Tap water is your safest alternative. Most people do not realize just how regulated municipal water is. In addition, those who sell home water products use fear mongering techniques to instill the unwarranted fear that tap water is not safe.
The municipality I work in has a policy of full disclosure. We provide detailed records of all water tests on our website, and will provide them upon request. Please do not hesitate to contact your municipality, they will be most likely be more than happy to provide test results on concentrations of mercury and fluoride.
If you still would like to test your water for contaminants at your own expense, contact the USEPA. They will be able to guide you to the closest licensed laboratory for drinking water testing. It is important to use a licensed lab, as they have met minimum quality guidelines.
Finally, please refer to this article on about.com:chemistry. It gives some useful tips about reducing fluoride from your diet from water as well as sources that are not from drinking water.
I hope I’ve answered your question to your satisfaction. If you have any other questions, or need further clarification, please do not hesitate to write in again.
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