P14417: B9 Particle Filter Introduction & Background Results Results

Daniel Anderson, Thomas Heberle, Perry Hosmer, Karina Roundtree and Kelly Stover

Design and RequirementsEngineering Requirements

Goal: To help a local non-profit organization, B9 Plastics, improve water quality in the developing world with their “Better Water Maker” (BWM) water disinfection system by creating a pre-filter for the product. B9 would like to develop an inexpensive filter that would either have a very long life before replacement is required or that can be recharged/backwashed in the field for continued use and eliminate problems that currently exist. Background: The BWM is designed for use in developing countries where water is unsafe for drinking and electricity is scarce. The current BWM is a batch Ultraviolet (UV) disinfection system that treats ½ gallon per minute of water at a time. The overall effectiveness of a treatment system using UV light to disinfect water is dependent on the source water clarity (low turbidity), which is related to the particles that are either dissolved or suspended in the water. The design of our filter seeks to remove suspended particles and lower the water turbidity , thereby improving the effectiveness of the UV treatment process.

B9 Plastics, Inc. - Bob Bechtold - Kate Chamberlain Rochester Institute of Technology - Multidisciplinary Senior Design - Gerald Garavuso - Gary Werth - Mark Smith - Christine Fisher

- Professors - Dr. Scott Wolcott - Dr. Brian Thorn

- Dr. Marca Lam - David Hathaway - Dr. Hany Ghoneim - Dr. Surendra Gupta - Dr. Elizabeth DeBartolo CONSOL Energy - Tom Conner

Acknowledgements

Taste Testing

36.5%

23.0%

40.5%Prefered unfil-tered waterPrefered filtered waterDid not favor ei-ther

Overall, people either preferred our filtered water over tap and spring water. We met our marginal goal of over 50%.

0 200 400 600 800 1000 120017.417.617.8

1818.218.418.618.8

1919.2

f(x) = − 0.00122727272727273 x + 19.25R² = 0.809999999999999

Bristle Life

Number of Strokes

Leng

th o

f Bris

tles (

mm

)

Based on the Brush Durability Testing the expected life cycle for the brush is approximately 2.2 years which complies with customer requirement, of a life of 2-5 years.

1 2 3 4 5 60

100200300400500

Flow Through Time

Prototype 1 Prototype 2Analysis of Variance for Flow Through Time, using Adjusted SS for TestsSource DF Seq SS Adj SS Adj MS F PNumThrow 11 59388 11942 1086 0.28 0.965Prototype 1 138890 138890 138890 35.21 0.002Error 5 19725 19725 3945Total 17 218003

Based on the durability testing the overall assembly did not undergo any negative impact on the functionality of the filter when it was thrown off a building multiple times.

Importance Customer Requirement Function Metrics Units Marginal Target Concluded

Condition

3Easy to clean / recharge

Easy to prepare for use Time to clean Minutes <10 <5 Meets

Target

3Has a minimal start-up period. Minimize start-up

Time elapsed between beginning of pour and first water that enters the bucket

s (seconds) <30 <10 Meets Target

3

Usable by a family of 5, for 2-5 years w/out full replacement

Maximize durability of filter Mean Time To Failure Number of Uses >730 >3650

Meets Marginal

Goal

9

Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION

Turbidity is decreased Turbidity NTU 30 10

Meets Marginal

Goal

3

Does not negatively affect the taste of the water

No negative taste of water

Percent of people who say water tastes the same or better

% >50% >75%Meets

Marginal Goal

3 Use scenariosProvides enough water for family of 5, daily

Flow rate lpm 0.0394 0.631Meets

Marginal Goal

Durability Testing

Turbidity Testing

1.00.80.60.40.20.0

X_

Ho

Percent Reduction

Boxplot of Percent Reduction(with Ho and 95% t-confidence interval for the mean)

One-Sample T: Percent Reduction Test of mu = 0.5 vs > 0.5 Variable N Mean StDev SE Mean Bound T P%Reduction 19 0.6404 0.3183 0.0730 0.5137 1.92 0.035

Based on the turbidity testing, we can conclude with confidence that the turbidity of water which has passed through the filter experiences at least a 50% reduction. Because % reduction is not the best statistic, end state turbidities were also analyzed.

One-Sample T: End state turbidityTest of mu = 30 vs < 30 Variable N Mean StDev SE Mean T PEnd.Turbid 19 24.05 24.66 5.66 -1.05 0.154

80706050403020100

X_

Ho

End state turbidity (NTU)

Boxplot of End state turbidity (NTU)(with Ho and 95% t-confidence interval for the mean)

The end state turbidities can be said to be less than 30 at any significance level α ≤ .154. Using a strong statistic, rather than the weak statistic of percent reduction, allows the team to be more confident in the results.

Flow Testing

Our flow testing shows that while variation in flow rate is not entirely dependent on the turbidity of the source water, there is some indication that samples with higher turbidities will have lower flow rates.

Solids Removal

Dissolved and Suspended Solids

Avg. TDS (mg/L)

Avg. TSS (mg/L)

Avg. TS (mg/L)

River Unfiltered 333.17 77.21 410.38River Filtered 343.55 13.55 357.10

River % Reduction -3.12 82.45 12.98Pond Unfiltered 4309.67 420.00 4279.67

Pond Filtered 3879.03 33.33 3912.36

Pond % Reduction 9.99 92.06 17.28Pond water prior to filtration Pond water after filtration

Analysis was performed to assess the effectiveness of the filter screen in removal of dissolved, suspended, and total solids. Based on tested samples, the filter was able to remove 82% of suspended solids from river water, and 92% from pond water.