Human Powered

Producing Potable Water for Developing Countries

Dustin Drake, Alfonso Liguori, Jeremy Smith

Florida Atlantic UniversityDepartment of Ocean and Mechanical Engineering

Reverse Osmosis

Global Water CrisisOne billion people do not have access

to clean drinking water.

3.6 million people die each year from water-related diseases.

98% of water-related deaths occur in the developing world.

A person can only live for a few days without water.

Human Powered RO SystemPurpose:

Create a device capable of providing potable water to people in developing nations

Focus:Low costPortabilityQualityEfficient

Human Power Supply

Human Power SupplyFor long duration / low intensity operations

Human input = 0.1 hp Very sustainable for a healthy person Short duration / low intensity operations will not overly tire the

operator

For short duration / high intensity operations Human input = 0.2 hp Sustainable for durations less than 3 hours Will leave the operator very tired after extended operation

Human Input MechanismDesign Goals:

Simple, natural motion Pedal driven Efficient transfer of mechanical energy Portability Rigid Construction

Positive Displacement PumpDesign Goals:

High pressure (100 psi)Low flow rate (0.3 gpm)Low maintenance

Reverse OsmosisTwo liquids of different concentrations separated by semi-

permeable membraneLess saturated naturally flows into more

saturatedPressure is applied to reverse this

process and is known as reverseosmosis or RO

Dirty water flows throughmembrane thereby filtering it

dirty water clean water

Reverse Osmosis PurifierHighly efficientRelatively low cost4 stages of filtration:

Sediment filter Activated carbon filter RO membrane Activated carbon filter

RO Numerical AnalysisPower requirement:

(: Power, : volumetric flow rate, : pressure)

psi gpm

Hp

UV PurificationDisables reproduction of microorganismsRO system filters then filters them out

Most effective at 253.7 nm wavelengthDifferent microorganisms require different intensities

Intensity approx. 30 mJ/cm2

Power required depends on exposure time, affected by:Size of bulb and pipeFlow rate of water

Electrical GenerationProvide electrical power to UV lampDesign Criteria:

14 watt UV bulb Expected efficiency = 40% Human input = 0.047 hp

Practical FeasibilityOnly 0.066 Hp neededPerson can provide 0.10 Hp for 8 hrs

1 gallon produced in 10 minutesOne person needs ½ gallon daily5 min per person per day

Discussion Uses:

Developing nationsCamping/backpackingEmergency disaster response (e.g. FEMA)

Considerations:Approx. $500 totalRO membrane can last for 3-4 yearsSmall village could have clean water with one system

ConclusionViable

Efficient

Economical

Effective