A sustainable clarification process

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Biosand Filtration
A sustainable clarification process
EWB Workshop 2008 Martin Page, Ben Finnegan Jason
Jewell, Izaak Neveln
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waterCAMPWS

• Center of Advanced Materials for the Purification
  of Water with Systems
• A Science and Technology Center of the National
  Science Foundation
• www.watercampws.org

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A hands-on experience

• Background
• Design considerations
• Getting our hands dirty
• Discussion

www.biosandfilter.org
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Biosand filters use nature!
Fine sand
Pathogens removed by straining, adsorption,
natural death, predation
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Biosand filters are scalable.
www.indiawaterportal.org
www.blackburn.com
11,000 gpd Centralized, Small community
11 gpd Point-Of-Use, Household
100,000 gpd Centralized, Treatment Plant
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Advantages
bushproof.biosandfilter.org

• Clarify water (visible improvement)?
• Made using locally available materials and labor
• No chemical inputs
• Easy to maintain
• Not heavily mechanized (no pumps, backwashing,
  etc)?
• Higher flux than ceramic filters
• Health impact (household level)

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Disadvantages

• Centralized systems require large area
• Not sufficient as a single treatment step (not
  enough pathogen removal)?
• Turbid waters require pretreatment
• Capital intensive
• Require periodic cleaning, downtime, ripening time

www.biosandfilter.org
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Standard Design
www.cawst.org
Maintain water level above biofilm Provide
headspace/freeboard to account for increasing
headloss Protect the biofilm from scouring
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Construction
Build filter housing Locate and clean gravel,
coarse and fine Locate, sieve, and clean lots of
sand D10 0.25mm, UC lt 3 Fill and flush the
filters Ripen the filters
http//thewaterproject.org
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Your mission Join a team and build this
Fine sand
Fine gravel
Coarse gravel
Let's get to work!
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Discussion
What was the most difficult step? Which steps
would be more difficult at the full scale
(centralized system)? Would the filter you built
work in practice?
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Discussion
Several leading researchers are promoting the
large scale use of biosand filtration at the
household level what is your opinion? Other
questions??? Thanks for joining us, and enjoy
UIUC!