Analysis of Water Filter Efficacy. Stephen McDonnell Pittsburgh Central Catholic HS PJAS 2013 Grade 9

Transcription

1 Analysis of Water Filter Efficacy Stephen McDonnell Pittsburgh Central Catholic HS PJAS 2013 Grade 9

2 Water Filters The job of water filters it to clean water Different substances can be used to filter Activated Carbon Gravel Sand

3 Brita Water Filter Water is filtered using activated carbon. Activated carbon is electrically charged, such that the contaminants stick to the carbon, while the water continues through the filter. Certified by NSF International Filter states that one focus is on chemicals such as chlorine.

4 Pur Water Filter This filter has received the NSF Standard certification The filter has 2 layers Stage 1 Stage 2 Stage 1 is a sediment wrap which reduces dirt and sand. Stage 2 makes the water healthier by removing pollutants. It cleans water using activated carbon. One focus is on chemicals such as chlorine.

5 Great Value Filter Walmart This filter has received the NSF Standard certification, stating that it is safe to use. States that chlorine can be reduced. Activated carbon traps contaminants and keeps water flowing through. One focus is on chemicals such as chlorine.

6 DuPont Filter The filter has received the NSF Standard certification. This filter uses activated carbon to filter contaminants. One focus is on chemicals such as chlorine. It consists of 4 stages. Stage 1 cleans contaminants. Stage 2 improves taste. Stage 3 clarifies the water. Stage 4 protects the filter.

7 Homemade Water Filter A homemade water filter was used to symbolize what could be used in a 3 rd world country. The filter was layered with activated carbon, sand, and gravel. Carbon

8 Miracle-Gro Fertilizer 8% Nitrogen Fertilizer gives abundance of nutrients to plant. Contains nitrates and nitrites

9 Nitrate (NO 3 ) nitrogen-oxygen chemical units Formed by oxidation of ammonia to form nitric acid Manure of animals Excess can leech into the ground water and aquatic systems. It can also cause Blue Baby Syndrome.

10 Nitrite (NO 2 ) Toxic chemical High concentrations can result in death of animals and plants. Commonly found when fish tanks are not cleaned sufficiently Changing water often can prevent nitrite

11 Chlorine and Clorox Approximately 9.14% chlorine is in Clorox. Bleach Contains Chlorine (Cl) element Often forms compounds with other elements Sanitizes water High concentrations can be very dangerous.

12 Previous Studies A group of students experimented on how to make ocean water salt free. The following were tested: Plastic with small holes Paper towel Printer paper Printer paper tripled up The results supported the null hypothesis. The water tasted salty.

13 Problem Do water filters do a thorough job of cleaning out contaminants?

14 Purpose To find out how well different brands of water filters work on cleaning out contaminants.

15 Hypothesis Null Hypothesis: The water filters will not significantly reduce the concentration of the introduced contaminants. Alternative Hypothesis: The water filters will significantly reduce the concentration of the introduced contaminants.

16 Materials Pur water filter Pur water filter cartridge Brita water filter cartridge Great Value water filter cartridge DuPont water filter cartridge Miracle-Gro Clorox Wisk Water (1900mL) Dish rag Activated filter carbon Aquarium sand Aquarium gravel Nitrate and Nitrite strips Total chlorine testing kit DPD Total Chlorine Reagent Powder Pillow Beaker

17 Procedure: Filter Cartridges 1. Cartridges were placed in a beaker and soaked in cold tap water for 15 minutes. 2. The cartridges were flushed by holding them upright under cold running tap water for 15 seconds. 3. Excess water was drained from each cartridge.

18 Procedure: Nitrate/Nitrite drops of Miracle-Gro were added to 950 milliliters of water. 2. The liquids were lightly stirred. 3. The water was poured into the filter. 4. The water was given time to filter a sufficient amount to test (250mL). 5. The final levels of nitrate and nitrite were measured using the nitrate and nitrite test strips.

19 Procedure: Chlorine 1. 1 milliliter of Clorox was mixed with 950 milliliters of water. 2. The liquids were lightly stirred. 3. The solution was poured into each of the filtration systems. 4. A test tube was filled to the first 5mL line with the original concentration sample.

20 Procedure: Chlorine continued 5. The tube was inserted into the left opening of the chlorine testing kit. 6. The other tube was filled to the first 5mL with the finished sample. 7. DPD Total Chlorine Reagent Powder Pillow was added to the 2 nd tube. 8. After 6 minutes, the color wheel was put up to the tubes and they were compared.

21 ppm Average amount of contaminants left in each of the filters Homemade Filter Pur Brita Great Value DuPont Control Nitrate Nitrite Chlorine

22 ppm Average amounts of contaminants left in each of the filters (excluding nitrate) Homemade Pur Brita Great Value DuPont Control Nitrite Chlorine

23 ANOVA for nitrate results Anova: Single Factor SUMMARY Groups Count Sum Average Variance Column Column Column Column Column Column P-value: 1.93E-25 Null Hypothesis can be rejected. A significant change occurs. ANOVA Source of Variation SS df MS F P-value F crit Between Groups E Within Groups Total

24 Anova: Single Factor ANOVA for nitrite results SUMMARY Groups Count Sum Average Variance Column Column Column Column Column Column P-value: 1.17E-10 Null hypothesis can be rejected. A significant change occurs. ANOVA Source of Variation SS df MS F P-value F crit Between Groups E Within Groups Total

25 Anova: Single Factor ANOVA for Chlorine results SUMMARY Groups Count Sum Average Variance Column Column Column Column Column Column P-value: 6.19E-19 Null Hypothesis can be rejected. A significant change occurs. ANOVA Source of Variation SS df MS F P-value F crit Between Groups E Within Groups Total

26 Dunnett s Test Nitrate T Crit.= 3.9 Nitrite T Crit.= 3.9 Filter T-Value Interpretation Filter T-Value Interpretation Homemade Significant Homemade Significant Pur Significant Pur Significant Brita Significant Brita Significant Great Value Significant Great Value Significant DuPont Significant DuPont Significant

27 Dunnett s Test continued Chlorine T Crit. = 3.9 Filter T-Value Interpretation Homemade Significant Pur Significant Brita Significant Great Value Significant DuPont Significant

28 Percentage of Contaminants Filtered Out Filter Nitrate Nitrite Chlorine Pur 94% 4 th Brita 95.5% 3 rd Great Value 96% 2 nd DuPont 98% 1 st Homemade 75.5% 5 th 85% 3 rd 80% 4 th 97% 1 st 92% 2 nd 25% 5 th 100% 1 st 65% 4 th 98% 2 nd 90% 3 rd 24% 5 th

29 Best Filters Pur was best at filtering chlorine (about 100% was taken out) DuPont was best at filtering nitrate (about 97.78% was taken out) Great Value was best at filtering nitrite (about 96.67% was taken out) Overall, Great Value filtered the contaminants most effectively for the best price.

30 Other observations The price of each brand Pur: $7.18 Brita: $6.94 Great Value: $4.94 DuPont: $7.00 Each filtered at a different rate Pur: Filtered quickly Brita: Filtered slowly Great Value: Filtered incredibly slowly DuPont: Filtered quickly

31 Conclusion The null hypothesis was rejected in all cases The water filter cartridges all had a significant effect on each of the contaminants. The homemade filter was the least effective filter, but it still filtered a significant amount.

32 Limitations Extensions Only 1 brand of pitcher was used Only 1 type of filter was used Only 3 contaminants were used Test different contaminants Test different types of filter systems Use higher concentrations of contaminants Test a bacteria on each of the filters

33 References asp cinformation/nitrate.cfm