1. Detailed Design Review: Pre-Filter P13418
Dan Charles
John Markidis
Israel Powell
An Vu

2. Customer Needs And Objectives
CN1
The filter is inexpensive
CN2
The filter improves UV transmission
CN3
The filter removes particles
CN4
The filter removes fluoride
CN5
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/recharge
CN8
The filter does not negatively change the taste of the water
CN9
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 feed
CN11
The filter has a minimal start up period
CN12
The filter is lightweight for transport

3. locally available and cheap
Specifications
Specification Number
Specification
Direction
Units
Marginal
Ideal
Test Plan S1
Production Cost
min $
<20
<10
Cost Analysis S2
Maintenance costs per 1000 L water treated
$1/1000L
<2
<1
Calculate life span and Cost to replace parts likely to fail and the adsorbent material on a regular basis S3
Reduction of particles >5u
max % 50 75
Nephelometer S4
Reduction of turbidity S5
Reduction of TSS
Filter, Dry in Oven S6
Reduction of Fluoride 70
Fluoride Test Strips S7
Estimated filter life
hrs
6000
Based on manufacture lifespan S8
Consumable parts
min 
locally available and cheap
none
Bone Char: Find the most efficient/lowest cost f the adsorbent S9
Time to disassemble and reassemble housing
Min
<30
<15
Time the disassembly and reassembly of housings
S10
Time to recharge media
<8
<4
Use a stop watch to time how long. Check that the bone char was actually recharged; reuse for fluorine removal and compare it to results of fresh bone char
S11
Number of tools required to dis/assemble
 Min 2 1
Count number of tools
S13
% of people who say the water tastes the same or better
>50
>75
Smell the water to see if the water smelled the same better or worse than the orignal sample
S14
Release of dangerous chemicals/materials into the water no
Analyze possible sources of polution, use mass spec or ir to analyze components of the water and/or send to an outside lab for testing
S15
Flowrate at 1.5 m head
Lpm
>2
>4
Record rate at which the filter is pushed through the bucket
S16
Water passed (untreated) during start up period L
<100
S17
Weight for shipping kg
Weigh the system

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

5. System Architecture

6. Initial Concentration
Fluoride Removal
Known
Volume 5
gal →
18.93 L
Concentration Initial 20
mg/L
Concentration Final 10
Life of Filter
6000
hours
Cost of Bone Char
5.58
$/lb
Initial Concentration
Amount of Fluoride per 5 gal bucket Initial 20
mg/L
379 mg
Equilibrium Concentration (50% Reduction)
Amount of fluoride per 5 gal bucket final 10
189
Fluoride Adsorbed
Fluoride Adsorbed onto Bone Char

7. Test Method Fluoride concentrations varied from 1 to 20 mg/L
Batch adsorber, 500 mL polyethylene container
Nylon mesh containing the granular bone char were placed together inside the plastic
Continuously stirred with a magnetic stirrer
The solution remained in contact with the bone char until equilibrium was reached (just over 1 day)

8. Freundlich Isotherm Variables ( 25°, pH=7 )
𝑞=𝐾 𝐶 1 𝑛
Freundlich Isotherm Variables ( 25°, pH=7 )
Mass of fluoride adsorbed per mass of adsorbent q
mg/g
Adsorption capacity K
2.71
(mg1-1/nL1/n)/g
Concentration of fluoride at equilibrium C 10
mg/L
Intensity
1/n
3.52
Percent Devation %D
4.6
Adsorption of Fluoride from Water Solution on Bone Char
Nahum A. Medellin-Castillo,† Roberto Leyva-Ramos,*,†,‡ Raul Ocampo-Perez,†
Ramon F. Garcia de la Cruz,† Antonio Aragon-Pin˜ a,† Jose M. Martinez-Rosales,§
Rosa M. Guerrero-Coronado,† and Laura Fuentes-Rubio†

9. Cost of Fluoride Removal
Life of Filter
Water Processed
720000 L
Number of Buckets
Buckets
Fluoride Removed mg
Bone Char Required g lb
Cost $
Bone Char
g/L →
0.024
$/L
g/Bucket
0.447
$/5 gal bucket

10. Cost of Fluoride Removal
The life-time cost is extremely high ($16,000), but the cost of per 5 gallon bucket ($.44) is more reasonable
It takes about 24 hrs to reach equilibrium
Time can be reduced with agitation, increases the rate at which the bone char and fluorine ions come in contact. However the time limiting step of adsorption will not be increased by agitation.
Adding more bone char will allow the objective of a 50% reduction to happen faster, but will increase the cost.

11. Architecture

13. Mesh

14. Test Plan

15. Test Plan Continued