We believed that using a combination of different household materials to filter our water would work best for creating lower tds (total dissolved solids) readings. We hypothesized that our filter combination of paper towel, rocks, and sponge would work the best for filtering, and that the rock filter alone would work the least well for filtering. We estimated the following tds readings based on the materials we were using.

TDS Meter Estimates (higher readings = worse)

9000-9990 tds - Rock Filter - because of the spaces between the rocks.

8000-9000 tds - Nylon - because it stretches and isn’t thick but does have lots of small holes in it

6000-7000 tds - Coffee Filter - because it seemed really thin

6500-7500 tds - Cotton Pads - because the spaces between the cotton pad are much smaller than the rocks and it has multiple layers.

6000-7000 tds - Sponge - because it has 2 different material layers to block out more of the solids

550-6500 tds - Cheese cloth - because we thought we could layer it a lot to make it filter out solids

5000-6000 tds - Paper Towel - because it can be folded and has different sizes of holes because of the pattern on it. 

5000-7000 tds - Surgical Face Mask - because this was used during Covid for keeping other people safe and we thought it could filter lots of different types of solids 

4000-6000 tds - for the Combination of Rocks, Paper Towel, and Sponge - because the different materials would filter out different types and sizes of solids

Slideshow

Dirt water: Level of dirtiness: We plan on using the same water for all of our experiments to ensure this works
Filters we use: 

Starting level of dirtiness: We will use a TDS Meter to track how dirty it starts. 

Water after filter

Materials 

-measuring cup 

-dirty water

-cups

-TDS meter

-funnel       

-  Filters: coffee filter, sponge, cotton pads

surgical face mask, rocks, paper towel

nylons, and cheesecloth

How we did it:

1. We got 100 ml of tap water
2.  We used a TDS meter to see how dirty the water started.
3. We found household materials and bought resources 
4. We put a rubber funnel in a measuring cup and then put on a coffee filter and the household material we are testing
5. We poured the water into the filter and started a stopwatch to track how long it took.
6. After the water had all gone through the filter we stopped the stopwatch and put a TDS meter in the water to measure total dissolved solids.
7. We repeated steps 3-6 for the remaining filters
8. We went outside and got some muddy water and added dirt and salt.
9. We repeated steps 2-7 for dirty water

We noticed that many of the filters soaked up water during our experiment. The quantity of liquid measured in ml was almost always less, after most of the filters did their work. The worst offender was the cheesecloth, which absorbed 70 ml of dirty water, and 40 ml of tap water. The second worst was the paper towel, which soaked up 30 ml of tap water and 70 ml of dirty water. From this, we noticed that the dirty water was soaked up much more because of the solids that didn’t make it through the filter. The dirty water also took much more time to pass through the filter, because of the solids.

The longest time for tap water to pass through the filter was 1 minute 40 seconds, and the longest time for dirty water to pass through a filter was 15 minutes and 35 seconds.

Surprisingly, we also saw that the TDS reading was actually higher when we filtered tap water through cotton pads and cheesecloths.

We noticed the samples we collected from the dirty water part of the experiment separated into layers after a little time passed. The water seemed clearer than it actually was, until it was shaken, because a tiny layer of sediment settled to the bottom of the jar over time. 

The coffee filter water became separated into 3 layers. The top layer had grass, the middle looked like light brown water, and the bottom had a layer of soil and sediment.

By the next day, most of our jars had water that looked brownish-clear and appeared much cleaner, but when shaken, they turned back to a murky colour again.  

Materials 

• Stopwatch
• measuring cup 
• Dirty Water
• Tap Water
• Glass jar
• TDS Meter
• Funnel
• Filters: coffee filter, sponge (cut into cubes), cotton pads, surgical face mask, rocks, paper towel, nylons (knee high stockings), and cheesecloth (3 25 x 25 squares)

Procedure

1. We placed a rubber funnel in a glass jar
2. We placed a coffee filter in a glass jar
3. We got 100 ml of tap water
4. We tested water with a TDS meter
5. We poured 100 ml of water through the coffee filter & funnel. We started stopwatch
6. When the water finished going through the funnel we stopped the stopwatch and used TDS meter to get recording
7. There was no difference so we decided to use the coffee filter to contain testing material in each of the tests
8. We measured 100 ml of tap water
9. We used a TDS meter to get an initial reading of total dissolved solids.
10. We collected household materials (coffee filter, sponge, cotton pads, surgical face mask, rocks, paper towel, nylons, and cheesecloth).
11. We put the funnel in the glass jar coffee filter and then added a coffee filter
12. We added the household material we are testing.
13. We poured the water into the filter and started a stopwatch to track how long it took.
14. After the water had all gone through the filter we stopped the stopwatch and put a TDS meter in the water to measure total dissolved solids.
15. We repeated steps 11-14 for the remaining filters (coffee filter, sponge, cotton pads, surgical face mask, rocks, paper towel, nylons, and cheesecloth)
16. We went outside and got some muddy water and added dirt and salt.
17. We repeated steps 2-7 for the dirty water.

In our experiment, we tested various materials to see how 

Effectively they could filter water and remove total dissolved solids (TDS). The best-performing filter was the combination of rocks, paper towels, and sponges, which removed a total of 700 ppm of dissolved solids overall. On the other hand, cotton materials performed poorly. Cheesecloths added 275 ppm. Based on these results, we concluded that cotton is not effective at filtering water.

The best performing materials, such as Rocks, Sponges, and Paper towels, made the water much clearer. Another thing we considered was the speed of filtration. Some materials, like Paper towels and Sponges, filtered the water quickly, while ones such as the Cheesecloth, took longer. This was probably because of the density and texture of the materials.

One thing we noticed during the experiment was how some of the materials seemed to soak up a lot of water. For example, the Cheesecloth soaked up 70 ml of water out of the 100ml total, between the two types of water. This made us realize that materials which absorb too much liquid should be avoided, as they reduce the overall amount of filtered water.

Disclaimer: TDS only measures solids in water and does not mean that the water is drinkable.

These filters are useful if you want to clean dirty dishwater and use it to water plants. Just imagine if there was another water limit. You could reuse water while being sure it was safe for your plants. Though it is not drinkable if you used dirty water these filters could improve the taste of tap water.

The tap water's starting TDS Fluctuated throughout the day so the results were different. The way we solved this was by instead of just comparing the final TDS we compared the differences from the starting TDS. Another source of error was us not realizing that the TDS meter had a x10 thing for reading larger TDS values so we thought the dirty water wasn't dirty enough. We got around this by using some leftover dirty water from our bucket.

TDS Meter what it is and do you need it. Aquasana website. www.aquasana.com/info/tds-meter-what-is-it-and-do-you-need-it-pd.html?srsltid=AfmBOopvHDJgDeByf1qcUNTmaYvvLgl_AmCaCgKpGEER6xTDyUSOhyou

we acknowledge the use of Wikipedia and google for the ideas of our filters and how to make them we also used a Aquasana article about tds filters 

We would like to acknowledge our parents for their incredible help on the trifold, revising, and running the experiment