Particle and Fluoride Pre-Filter for B9 Plastics

Dan Charles – Chemical Engineer John Markidis – Mechanical Engineering

Israel Powell – Chemical EngineeringAn Vu – Chemical Engineering

The main goal of this project is to develop a pre-filtration system to reduce turbidity and fluoride levels of water - before it enters the BWM.

Objective

Customer NeedsCustomer Needs And Objectives

CN1 The filter is inexpensiveCN2 The filter improves UV transmission CN3 The filter removes particlesCN4 The filter removes fluorideCN5 The filter can be used for 6000 hours without replacement

CN6 The filter requires no consumables for operation with the exception of very cheap and locally available materials like salt or soap, for example

CN7 The filter is easy to clean/rechargeCN8 The filter does not negatively change the taste of the waterCN9 The filter is safe to use (no release of hazardous materials)

CN10 The filter has a flow rate of at least 2 lpm using gravity feedCN11 The filter has a minimal start up periodCN12 The filter is lightweight for transport

SpecificationsSpecification Number Specification Direction Units Marginal Ideal Pass / Fail

S1 Production Cost min $ <20 <10

S2 Maintenance costs per 1000 L water treated min $1/1000L <2 <1

S3 Reduction of particles >5u max % 50 75

S4 Reduction of turbidity max % 50 75 S5 Reduction of TSS max % 50 75 S6 Reduction of Fluoride max % 50 70 S7 Estimated filter life max hrs 6000

S8 Consumable parts min locally available and cheap none

S9Time to disassemble and reassemble housing

Min min <30 <15

S10 Time to recharge media Min hrs <8 <4

S11Number of tools required to dis/assemble

Min 2 1

S12recharge materials are common household items

no yes

S13% of people who say the water tastes the same or better

max % >50 >75

S14Release of dangerous chemicals/materials into the water

Min no no

S15 Maxium Force Needed to Filter max N <250 <100

S17 Weight for shipping min kg <20 <10

S18 Rate of Water Processed min L/min >2 >4

Functional Decomposition

Reduce Drinking Water Contamination

Guide Water Flow Accept Water

Remove Particles Discharge Filtered Water Remove Fluorine Guide Water Between

System Modules Collect Filtered Water Provide Necessary Head Support Functional Loads of

the System Connect to BWM

House Particle Removal

System House Fluoride Removal

System

System Architecture

System

Model

Prototype

Cost AnalysisCost of 1 Unitc

Part Cost (US Dollars)2 Rings 4

2 Handles 8Bucket 5Mesh 2.5

Bolts/Srews 0.5Rubber Gasket 2

Total Cost 22

Testing Data

TurbiditySample 1 (River Water)

Unfiltered FilteredTrial Turbidity (NTU) Trial Turbidity (NTU)

1 31.7 1 4.112 26.9 2 3.483 25.8 3 4.11

Average 28.13 Average 3.90Average Percent Reduction 86.14%

Sample 2 (Pond Water)Unfiltered Filtered

Trial Turbidity (NTU) Trial Turbidity (NTU)1 20.9 1 6.012 26.3 2 6.173 22.1 3 6.10

Average 23.10 Average 6.09Average Percent Reduction 73.62%

Total Suspended Solids

Total Suspended Solids (River Water)Unfiltered

Trial Initial Weight(mg)

Final Weight(mg)

TSS(mg/10mL)

TSS(mg/L)

1 258.5 263.8 5.3 5302 258.1 263.8 5.7 5703 263.2 269.0 5.8 580

Filtered

Trial Initial Weight(mg)

Final Weight(mg)

TSS(mg/10mL)

TSS(mg/L)

1 257.1 261.1 4 4002 253.9 258.0 4.1 4103 273.3 277.2 3.9 390

Average Percent Reduction 28.6%

Total Suspended Solids

Total Suspended Solids (Pond Water)Unfiltered

Trial Initial Weight(mg)

Final Weight(mg)

TSS(mg/10mL)

TSS(mg/L)

1 270.2 277.8 7.6 7602 423.1 431.1 8.0 8003 252.9 261.0 8.1 810

Filtered

Trial Initial Weight(mg)

Final Weight(mg)

TSS(mg/10mL)

TSS(mg/L)

1 272.7 278.9 6.2 6202 262.9 268.6 5.7 5703 256.8 263.5 6.7 670

Average Percent Reduction 21.5%

Fluoride AdsorptionBone Char Fluoride Adsorption

SampleNaF

Concentration(mg/L)

Bone Char(mg)

Dilution Concentration(mg/L)

F- Concentration(mg/L)

F- Removed

(mg)

mg F- Removed Per g Bone

Char

1 54.8 267.7 20 1.01 20.2 0.228 0.852

2 54.8 147 20 1.13 22.6 0.084 0.571

3 54.8 70.1 20 1.06 21.2 0.168 2.397

4 54.8 0 20 1.20 24

5 102.0 539.1 40 1.18 47.2 0.408 0.757

6 102.0 271.6 40 1.03 41.2 0.768 2.828

7 102.0 132.2 40 1.22 48.8 0.312 2.360

8 102.0 0 40 1.35 54

Average Sorption 1.627

Results

Particle Removal

Particle Removal• Reduction of turbidity was much greater than that

of total suspended solids, due to the fact that larger particles have a much greater effect on turbidity than smaller particles.

• For our objective, turbidity is a more relevant specification. Turbidity is a measure of light scattering, therefore the higher turbidity the greater amount of UV light that would be blocked.

• The goal for turbidity was achieved and surpassed during testing.

Fluoride Adsorption• The adsorption of

fluoride ions onto bone char has been widely studied

• Conclusions have been made both for and against using bone char to remove fluoride from water

• Our results were erratic but did consistently show fluoride was removed from the water

Bone Char Based Bucket Defluoridator in Tanzanian

Households

• 2 Months of Operation

• 32.5 L/day were treated

• Average pH 8.56

• Sorption 1.1 (mg F-)/(g Bone Char)

• $10 per unit

Bone Char Based Bucket Defluoridator in Tanzanian

Households

Improvements

Improvements• Straight-walled bucket

o Companies had minimum order restrictionso Not sold locally

• Better support for handleso Extruded shells on rings to hold base of handleso Original handle base supports built into CAD files

Vs.

• In extreme cases of turbidity, pre-filtering with a t-shirt is recommended

• Improve device function: Large amount of suction created makes filter difficult to pull out from bucket

• Provide lid for handle support and keeping filter level

Improvements

• Were not able to buy the mesh from Chinao Mesh we purchased took up roughly 1/3 of our budget

• Gaskets were hand cut

• >5micron particle test o When drying the filter paper, weighed less than initial weight

• Fluoride test strips required acidifying the sample to a 0.5 pH using concentrated hydrochloric acid

MSD II Obstacles

Thank You