Transcript Remote Location Water Filtration Station

Senior Design Project 2004 ~ Mid-Term Design Review
Remote
Water Purification
Team Members:
Ndubuisi Nduaguba
Neusa Veiga
Joel Patruno
Piseth Toch
Outline
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Problem Assessment
Physical Filtering Stage
Biological Sanitation Stage
Control System
Project Limitations and Challenges
Conclusion
Problem Assessment
• At least 1.1 Billion people do not have
access to clean drinking water sources1
• 2.2 million die every year from diarrheal
disease deaths annually (mainly children)1
• Parts of the world plagued by lack of
drinking water also do not have access to
electricity
• Our solution: Remote water purification
system.
Problem Assessment
• We are building a “stand alone” Water
purification system.
• We will utilize last year’s solar power supply.
– The source power supply is 1.9 A/H @ 12V (sunny day)
• The goal is to take 1.2 gallons of unclean
water and process it to meet bacterial
standards of drinkable water.
– This number is amount of clean water necessary for one person to live1
• Long, maintenance-free period of use.
• Low maintenance costs
• Fool proof operation
Problem Assessment
• To do this we must do the following
– Remove physical contaminants and debris
– Remove or destroy biological contaminants
– Store clean water in such a manner that it stays clean
• The system will be designed to pour in
water and walk away
• System should be scaleable
• We’ll consider a multi-stage operation to
fulfill these requirements
Preliminary Filter Cascade Design
Water Holding Pen
Physical Sediment Filter
Water flow Control System
Biological Sanitation
Storage / Collector
Outline
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Problem Assessment
Physical Filtering Stage
Biological Sanitation Stage
Control System
Project Limitations and Challenges
Conclusion
Physical Filtering Options
• Reverse Osmosis
– Highly effective in removing impurities from water
– Waste a large amount of water (3 to 9 gallons of
water per gallon of purified water produced
– treats water slowly; 1/4 gallon per hour
• Charcoal Filtering
– A carbon block filter consists of carbon bonded to
metal sheets
– Works quickly, several gallons per hour
– Life span generally from 250 to 1000 gallons
Physical Filtering Options
• Cloth Filtering
– Sari Cloth has been proven as a relatively effective
filter in 18 month study of Bangladesh villages2
– cloth is cheap and found everywhere
– Is this really enough filtering?
• Ceramic filtering
– Have long life up to 15,000 gallons
– Very effective filtering
– Does not filter large amounts of sediment, causes
clogging
Physical Filtering Options
• Dual Filtering
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Cloth is common and can be replaced regularly
Cloth acts to filter large contaminants
Increase ceramic filter life of next stage
These are gravity filters, no electricity or water
pressure needed
Ceramic Filter Element
 2 Black Berkey Ceramic Filters5:
– The upper bucket is filled with water which feeds
through the dual ceramic water filters
– Relatively small; 9in high and 3in diameter
– Durable and easy to clean
– Each filter lasts 2000 gallons between cleaning, and
have 15,000 gallon rated lifespan
– System can provide 24 gallons of “clean” drinkable
water per day; 1gal/hour; 2.1oz/minute
– Ability to reduce containments
• 95% reduction of heavy metals
• 85% reduction of Nitrates and Nitrites
• Reduces levels of pathogenic bacteria
Physical Filtering Solutions
• Description of dual physical filtering stage
– Ring holds cloth near top of 1st bucket
– Water filters through cloth into holding
chamber
– Water surrounds 2 black berkey ceramic filters
– Water filters through into the 2nd bucket
– Second bucket gathers filtered water for
biological sanitation stage
Outline
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Problem Assessment
Physical Filtering Stage
Biological Sanitation Stage
Control System
Project Limitations and Challenges
Conclusion
Biological Sanitation Options
destruction of bacteria and microbes
• Chlorine & chemical additives
– Proven to clean water well
– Short life of cartridge, added odor and taste; make this
unsuitable for our purposes Constant upkeep costs
• Electrolysis
– Uses electricity and plates to alter mineral composition of
water, but is an unproven method of sanitation
• UV Light
– Ultraviolet light with a wavelength of 254nm destroys the
DNA of cells – “UVC” light
– Poor penetration depth in Water
– UVC is available as a 12V powered Lamp; but is also
present in sunlight
UVC – Sunlight Sanitation
• Sunlight is FREE!
• UVC content in sunlight varies
greatly
• focusing & aiming apparatus to
increase UVC intensity
– We can concentrate the sunlight
using an elongated focusing mirror
– We already have an aiming device in
last year’s solar panel
• UV detection is tricky; detection
devices are pricey
• Sunlight is unreliable and not fool
proof
UVC – 12v Lamp Sanitation
• UVC output is constant
• Must build Sanitation Chamber
• Has lifespan of about 8,000 hours,
– At that point the hard glass begins to solarize and the
254 nm wavelength is no longer transmitted6
– Constant switching (on/off) of lamp reduces lifespan and
wastes valuable energy
• Our choice for lamp
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power consumption of 6 watts @ 12Vdc
measures ~14cm long and ~2.5cm diameter
Max “on-time” of Lamp is up to 4 Hrs on a sunny day
Power density output at 2cm is 40 mW/cm2 – in the UVC
range
UVC – 12 Lamp Sanitation
• To best utilize lamp, a
radial sanitation chamber
will be built around lamp
Amount of 254nm germicidal radiation
required for destruction of bacteria
Bacteria
– The outer Shell will be PVC
• The inner shell surrounding
the lamp must be clear but
Glass absorbs UVC
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– A 5mm thick Quartz tube
has 90% UVC
transmittance
The Absorption Coefficent7
of our water is ~ .2(cm-1);
18% loss @ 1cm
• Transmitted power density
through 1cm of water ~
29mW/cm2
• “Time to Kill” bacteria is
1.4 seconds in a best case
scenario
B. megatherium sp.(spores)
Energy to kill - in Power
Density Per Second
Sterilisation up to 99%
5.46
B.subtilis
14.20
B. subtilis spores
24.00
Escherichia coli
6.00
Micrococcus candidus
12.10
Micrococcus sphaeroides
20.00
Neisseria catarrhalis
5.28
Proteus vulgaris
7.00
Pseudomonas fluorescens
39.40
Spirillum rubrum
5.20
Staphylococcus albus
4.32
UV Chamber Logistics
• A Quartz tube and PVC pipe will form a
water way
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Designed to be used vertically
2 inlets/outlets per side
Inside diameter of quartz tube is 5cm
The “water gap” is ~ 1cm across
The UV lamp will sit in the middle and irradiate
the passing water
• Isolates Lamp from water
• Water acts as a cooling system for lamp
– The chamber will hold ~ 8.5oz per cycle
– 3 seconds in the chamber will be more than
enough to kill all biological contaminants
Control System Overview
• Next semester’s Big project.
• A water-level activated switch
– Will turn on when enough water gathers in the 2nd
bucket.
• The UV lamp will turn on
• A number of cycles will then be passed through
the UV chamber
– 5 ounces will constitute as a cycle to discourage cross
contamination
– A pinch valve will open and close in time to allow for
proper exposure to UVC light
– After all the cycles are up the lamp will turn off
– A control for this system will be implemented with a
state machine using VHDL and PLDs
Preliminary Control Logic
Outline
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Problem Assessment
Physical Filtering Stage
Biological Sanitation Stage
Control System
Project Limitations and Challenges
Conclusion
Modified Design
Project Limitations & Challenges
• Our PRIMARY objective is to achieve
clean drinkable water.
• Remove any and all possible bacteria
and viruses that can affect humans.
• Multi-stage sanitation to remove
organisms of varying sizes.
Limitation and Challenge One: Energy Supply
Why is our energy limited?
The sun is our only
source of energy
The UV lamp has to be ON longer
than if we were to sanitize
in air
On cloudy days our battery can
only partially charge so we
need to make sure the battery
isn’t over used
We are sanitizing water so the
absorption rate comes into play
Limitation and Challenge Two: Product Cost
• Designed for locations where energy is
limited, i.e. poor countries
• We need to balance cost and
effectiveness of our components in
order to keep the system affordable
• Keep maintenance to a minimum
• Scalability is an important consideration
in the design
Budget Considerations
Preliminary Working Budget
Quantity
Price per
unit
Total
Ceramic filters
1
80
80
UV unit
1
150
150
Tubing
1
10
10
Quartz unit
1
50
50
Pinch Valve
1
50
50
Housing
1
50
50
Gear
1
10
10
control system
1
100
100
Item
Total
500
Conclusion
• We want to remove physical
contaminants, plus all bacteria and
viruses harmful to humans
• Target users are poor countries where
clean water is unavailable
• Designing a scalable dual stage
purification system of physical and
ultraviolet stages
• Keep cost and maintenance low so that
it can be applied to our target users
Bibliography
• 1 – World health Organization – Water Sanitation report http://www.who.int/water_sanitation_health/monitoring/en
/Glassessment6.pdf
• 2 – BBC News report on world water supplies.
http://news.bbc.co.uk/1/hi/health/2640307.stm
• 3 - Pacific Institute of Water
http://www.pacinst.org/water_facts.html
• 4 - http://www.jamesfilter.com/blackberkey.htm
• 5 - Black Burkey FAQ page
http://www.jamesfilter.com/frequently_asked_water_filter_
qu.htm
• 6 – Watrex Ultraviolet Sanitizer
www.watrex.be/english/uv.html
• 7 – Pollution Prevention Report Page 13:
http://www.p2pays.org/ref/03/02919.pdf
Questions ?