I need some help on equipment!!!!

[Bri]

Hi!!!
I'm doing my science fair project on water purification, and I heard that there is a kind of paper out there that will turn a certain color when the water is purified. Is this true??? If so, where can I get some? If not, what other methods can I use to see if water reaches drinking water standards???
Thank you!

[ChrisG]

Hi Bri,
I have never heard of a test as simple as that. Public water suppliers are required to submit samples for numerous, expensive analyses to confirm the presence or absence of the many contaminants that are regulated by state and federal agencies. For example, for a list of the Environmental Protection Agency's drinking water standards, see
http://www.epa.gov/safewater/contaminants/index.html
States have additional regulations for contaminants that may or may not be on that list. In addition there are "emerging contaminants" that might pose health hazards but are not yet regulated, and there are probably contaminants that are so unusual or seldom studied that we don't know anything about their potential health risks in our water.

In summary, the question of what methods can be used to determine if water is "pure" is actually a very complicated question. Different contaminants require different types of analyses. Many of these analyses are very complicated and expensive.

As a way to approximate whether water might be contaminated, some people use measurements of electrical conductivity, which is a very quick and easy measurement. You could look into using that approach as a basis for your project. If you'd like to tell us more about your plans for your science fair project, we can offer some more specific advice.

Good luck!
Chris

[Bri]

Firstly, I'd like to thank you for the help, Chris. Unfortunately, I still need a little help.

My experiment consists of two cups: a cup of dirty water and an empty cup. I'll be placing the 1st cup slightly higher than thesecond and then connecting them with different purifiers(cotton, polyester, bath towels, etc.). I'll be seeing which of them cleans the water the best to drinking standards. The point of the experiment is to present an easier, cheaper alternative for victims in hurricanes or other disaster situations rather than trying to get water some other way(buying, etc.) I need a way to see if the water I test reaches the standard for drinkable water that will suffice until more water is transported there. I'm not sure what water would be there that would need purifying and what will be in the water.

So I guess my two questions are 1) What contaminents should I put in the water that I will be testing and how much? and 2) How can I know if the water is drinkable without actually drinking it myself? (something cheap and easy, if possible...I don't have too many resources)

Thanks so much!!!!
Bri

[ChrisG]

Hi Bri,
Thanks for giving us more details about your experimental procedure. That is very helpful. It sounds like an interesting experiment with lots of possibilities.
I think you are aware that you will probably not be able to evaluate whether the water meets "drinking water standards" as that term is commonly understood. As mentioned above, the drinking water standards are very complicated and it is very expensive to evaluate whether water meets those standards. You will need to choose one particular kind of contaminant that is relevant to the problem you mentioned (recovery after a disaster) and can also be tested relatively simply.
During a natural disaster there are different kinds of contaminants that can enter the water supply. Salt water is one possible problem in coastal areas, and that cannot be filtered with any of the methods you've mentioned. Microbial contaminants are another possibility, and those might be more suitable for your experiment. Microbial concentrations can be estimated using plate culturing methods, which are described in this project:
http://www.sciencebuddies.com/science-f ... p007.shtml
You could mix a little soil into the water in the upper cup to introduce microbes, and then compare concentrations of microbes before and after filtration.
I hope that helps. There are other possibilities as well, if you'd like to continue to explore possibilities, but I think the microbes would be your best bet.
Chris

[Bri]

Hi Chris!
Thanks for the help, but I don't really know what a "microbe" is....if that's what it was....
Could I have a little more help?
Thanks!
Bri

[kgudger]

Welcome to the Science Buddies Forums! I don't know the context of your question, but here is a good definition of "Microbe" (Microorganism): http://en.wikipedia.org/wiki/Microbe Let us know if you have more questions!

Keith

[Bri]

Thank you so much, Keith!!!
As for the context of my question, I'm doing a project on how to filter out water in case of a disaster situation (hurricanes mainly...) with the use of household materials (paper towels, cotton, polyester, bath towels, etc.). I'll be filtering water from one cup to another with those materials connecting them. I wasn't sure what contaminents I should put in the water and how to see if the water is clean. In fact, I'm still not very sure how I can do this. I do think I'll be adding soil with thanks to Chris, but I'm not really sure if I should add salt, considering that some disasters happen in coastal areas.....I know my experiment probably won't remove the salt but that doesn't mean it's not there.
Any thoughts?
Bri

[kgudger]

Welcome back. I looked into what kind of contaminates we want to filter out of water, and found several good references. First, here's all of the contaminates the EPA worries about: http://www.epa.gov/safewater/contaminants/index.html. (If that doesn't scare us, I don't know what would...

There are essentially 3 types of contaminates I can think of. The first one that comes to mind are coliform bacteria, since these cause many immediate types of problems. This may be too dangerous for you to test. Secondly are minerals, such as salt, as you mentioned. Lastly are organic chemicals (such as gasoline, solvents, etc.) It might be informative to look at the sizes of these various contaminates. Filters are often rated by the size of the particles they filter out. Your background research could include this information. It might be a good idea to find some safe inorganic minerals of various sizes to test your filter material on its ability to filter. You could compare the sizes of these molecules with the sizes of common contaminates, and not have to use dangerous chemicals or pathogens. Just some suggestions, I hope these help.

Keith

[ChrisG]

Hi Bri,
I merged your new topic with your old one so that experts can see all the information about your project and what advice has already been given. Please keep future posts about your project in this thread. Thanks!

I would recommend choosing one single contaminant to use in your experiment. It's true that there are many different kinds of contaminants that can affect public water supplies after a hurricane, but it would be too time consuming and expensive to try to test for all of them in your experiment.

I hope that helps.

Chris