An Overview of Graywater Collection and Treatment Systems

1
An Overview of Graywater Collection and Treatment
Systems

• Ramadan Alkhatib
• Dr. Larry Roesner
• Christine Marjoram
• Department of Civil Engineering
• Colorado State University

2
Graywater?

• Wastewater that has not come into contact with
  neither toilet wastes nor kitchen wastes.
• ? Wastewater from bathtubs, showers, wash
  basins, washing machines, and laundry tubs

3
Graywater Uses

• Landscape irrigation
• Toilet flushing

4
In the USA

• Graywater has been in use without an official
  permit for irrigation purposes (Especially in
  times of droughts)
• No federal guidelines or regulations
• Official authorities?

5
Examples

• The State of California recommended a system that
  can be used by a homeowner
• State of Arizona, US allows surface irrigation
  (certain conditions apply)
• NSW Department of Health, Australia Issued
  accreditation guidelines for the domestic
  graywater treatment systems (DGTS)

6
Manufacturers

• Realized that new trend
• Designed graywater systems to
• Satisfy the requirements set by official
  authorities
• Get the acceptance of the people
• Diversion to treatment

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Five Systems Selected
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1) Earthstar Graywater System

• 55 gal tank
• Sand filter
• Automatic float switch
• Pump

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2) Clivus Multrum System

• Dosing basin
• Submersible pump
• Level control float

Source http//www.clivusmultrum.com/greywater.htm
l
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3) A Graywater System in Germany

• Found in the German Water
  Sector Report
• A mini-scale WWTP
• Coarse filter
• Two aerated chambers
• Sludge extraction
• UV disinfection
• Water storage
• Drinking water feedback
• Aeration device

Source http//www.umweltbundesamt.org/wsektor/was
serdoku/english/frameset_e.html
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4) Greywater Saver

• Australian owned
  patented

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5) California Graywater System

• Sealed, locked, and vented tank
• A warning sign
• 3-way valve
• An overflow to sewer

• Source California Revised Graywater Standards

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Graywater System at CSU

• 300 gal tank
• Different treatment units
• Aeration
• Sand filter
• Coarse filter
• 5mm filter
• UV unit

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Conclusions

• A wide range exists
• In the US, irrigation use is the most common
• Biological treatment worked in several cases
• Storage is necessary to use water whenever it is
  needed
• Not enough guidance on the use of graywater

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...Conclusions

• For a homewoner simplicity, flexibility, and
  cost
• For regulating authorities effectiveness and
  reliebility
• Need a system that is capable of collecting,
  storing, treating, and applying graywater