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Remote Water Purification

Senior Design Project 2004 ~ Mid-Term Design Review. Remote Water Purification. Team Members : Ndubuisi Nduaguba Neusa Veiga Joel Patruno Piseth Toch. Outline. Problem Assessment Physical Filtering Stage Biological Sanitation Stage Control System Project Limitations and Challenges

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Remote Water Purification

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  1. Senior Design Project 2004 ~ Mid-Term Design Review Remote Water Purification Team Members: Ndubuisi Nduaguba Neusa Veiga Joel Patruno Piseth Toch

  2. Outline • Problem Assessment • Physical Filtering Stage • Biological Sanitation Stage • Control System • Project Limitations and Challenges • Conclusion

  3. 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.

  4. 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

  5. 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

  6. Preliminary Filter Cascade Design

  7. Outline • Problem Assessment • Physical Filtering Stage • Biological Sanitation Stage • Control System • Project Limitations and Challenges • Conclusion

  8. 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

  9. 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

  10. Physical Filtering Options • Dual Filtering • 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

  11. 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

  12. 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

  13. Outline • Problem Assessment • Physical Filtering Stage • Biological Sanitation Stage • Control System • Project Limitations and Challenges • Conclusion

  14. 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

  15. 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

  16. 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 • 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

  17. UVC – 12 Lamp Sanitation Amount of 254nm germicidal radiation required for destruction of bacteria • To best utilize lamp, a radial sanitation chamber will be built around lamp • The outer Shell will be PVC • The inner shell surrounding the lamp must be clear but Glass absorbs UVC • 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

  18. UV Chamber Logistics • A Quartz tube and PVC pipe will form a water way • 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

  19. 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

  20. Preliminary Control Logic

  21. Outline • Problem Assessment • Physical Filtering Stage • Biological Sanitation Stage • Control System • Project Limitations and Challenges • Conclusion

  22. Modified Design

  23. 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.

  24. Limitation and Challenge One: Energy Supply

  25. 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

  26. Budget Considerations Preliminary Working Budget

  27. 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

  28. 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

  29. Questions ?

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