Detailed Design Review:

Pre-FilterP13418

Dan CharlesJohn MarkidisIsrael Powell

An Vu

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 Test Plan

S1 Production Cost min $ <20 <10 Cost Analysis

S2 Maintenance costs per 1000 L water treated min $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 NephelometerS4 Reduction of turbidity max % 50 75 NephelometerS5 Reduction of TSS max % 50 75 Filter, Dry in OvenS6 Reduction of Fluoride max % 50 70 Fluoride Test StripsS7 Estimated filter life max 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 min <30 <15 Time the disassembly and reassembly of housings

S10 Time to recharge media Min hrs <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 max % >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 Min no 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 max Lpm >2 >4 Record rate at which the filter is pushed through the bucket

S16 Water passed (untreated) during start up period min L <100 <20

S17 Weight for shipping min kg <20 <10 Weigh the system

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

Fluoride RemovalKnown

Volume 5 gal → 18.93 L Concentration Initial 20 mg/L Concentration Final 10 mg/L Life of Filter 6000 hours Cost of Bone Char 5.58 $/lb

Initial ConcentrationAmount 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 mg/L189 mg

Fluoride AdsorbedFluoride Adsorbed onto Bone Char 10 mg/L

189 mg

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)

Freundlich Isotherm

Freundlich Isotherm Variables ( 25°, pH=7 ) Mass of fluoride adsorbed per mass of adsorbent q 5.21267 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

𝑞=𝐾 𝐶1𝑛

Adsorption of Fluoride from Water Solution on Bone CharNahum 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†

Cost of Fluoride Removal

Life of Filter Water Processed 720000 L

Number of Buckets 38040.7 Buckets

Fluoride Removed 7200000 mg

Bone Char Required 1381250 g

Bone Char Required 3045.13 lb

Cost 16991.8 $

Bone Char

1.918402802 g/L → 0.024 $/L

36.30980167 g/Bucket → 0.447 $/5 gal bucket

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 equilibriumo 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.

o Adding more bone char will allow the objective of a 50% reduction to happen faster, but will increase the cost.

Architecture

Mesh

Test Plan

Test Plan Continued