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Literature Review[edit | edit source]

1995 CCAT Rockmarsh Greywater Treatment System[edit | edit source]

Carol Laudry's senior thesis (March 1995) for the Department of Environmental Resources Engineering goes into great detail about the purpose, function, and design of the greywater marsh, i.e. subsurface flow constructed wetland (a greywater treatment system) at CCAT in 1995. The following statements describing the 1995 marsh come from Laudry's thesis:

  • The purpose of the pretreatment is to provide a preliminary removal of total suspended solids (TSS), grease and oils from the greywater stream arriving from CCAT, [as well as] additional head to the wetland system and easy maintenance (p 67). This pretreatment system consisted of a new 55-gallon tank that contained a catchment mesh, a splash guard, an oil/grease separator, a sediment basin, a raised exit pipe and an outside bottom spiket (p 67). On a regular basis, preferably weekly, the pretreatment tank should be cleaned (p 67). This involves composting the detritus intercepted by the mesh screen, and flushing out any sediments collected at the bottom of the tank (p 67). The wastewater after leaving the pretreatment tank flows through an underground pipe to a new sunk-in storage tank referred to as the distribution tank (p 71). The distribution tank has two openings: the inlet pipe comes in at the bottom and the outlet pipe exits at the top facing the marsh (p 71). The purpose of the rock marsh treatment system is to provide an effluent water quality meeting secondary treatment standards for the greywater generated by the center (p 71). Note: The pretreatment tank and distribution tank have been designed so that they will only be able to take bathtub water OR clothes washer water, NOT both at the same time.


California Legislation and Ordinances[edit | edit source]

City of Arcata Legislation and Ordinances[edit | edit source]

Irrigation Sizing[edit | edit source]

"Generally, estimating the square footage is more useful for lawn areas and subsurface drip irrigation systems while estimating the number of plants would be more useful for trees and shrubs irrigated by a mini-leachfield system" (DWR, 1995). The following table and formula are from the DWR Graywater Guide Book (1995).

Climate Relative Water Need of Plant Gallons Per Week
(Plant Factor) 200 SQ FT 100 SQ FT 50 SQ FT
CANOPY CANOPY CANOPY
Coastal low water using (0.3) 38 19 10
(ET*=1in/wk) medium water using (0.5) 62 31 16
high water using (0.8) 100 50 25


The gallons per week calculation for this chart was determined with the following formula:
Gallons per week = ET x plant factor x area x .62 (conversion factor.)(This formula does not account for irrigation efficiency. If your irrigation system does not distribute water evenly, extra water will need to be applied.)

DWR Graywater Guide Book Example:
The 1120 gallons of graywater per week produced by the Brown family in Sacramento could irrigate:
8 young fruit trees: 8 trees x 50 gal/tree = 400 gallons (high water using, 50 foot canopy)
8 medium-sized shade trees: 8 trees x 62 gal/tree = 496 gallons (medium water using, 100 foot canopy)
7 large shrubs: 7 trees x 31 gal/tree = 217 gallons (medium water using, 50 foot canopy)
total: 1113 gallons per week

Appropriate Vegetation for Greywater Irrigation[edit | edit source]

Greywater Vegetation[edit | edit source]

  • Ornamental vegetation
  • Orchards
  • Plants with edible portions that grow without contact to the soil
  • Alkaline Tolerant Vegetation
    • Selecting Trees & Shrubs for Alkaline Conditions by James P. Engel, White Oak Nursery, Copyright 2004, www.whiteoaknursery.biz
Trees for Alkaline Conditions
pH 5.0-7.4 Common Name Scientific Name
Silver maple Acer saccharinum
Sugar maple Acer saccharum
Serviceberry Amelanchier laevis
Bitternut hickory Carya cordiformis
Shagbark hickory Carya ovata
Tulip Tree Liriodendron tulipifera
White Pine Pinus strobus
Black Cherry Prunus serotina
Douglas Fir Pseudotsuga menziesii
Red Oak Quercus rubra
Japanese Tree Lilac Syringa reticulata
pH 5.0-8.0 Common Name Scientific Name
Bottlebrush Buckeye Aesculus parviflora
Paper Birch Betula papyrifera
American Hornbeam Carpinus caroliniana
Hackberry Celtis occidentalis
Redbud Cercis occidentalis
American Smoketree Cotinus obvatus
Persimmon Diospyros virginiana
Star Magnolia Magnolia stellata
Saucer Magnolia Magnolia x soulangiana
Little Leaf Linden Tilia cordata
American Elm Ulmus americana
Shrubs for Alkaline Conditions
pH 5.0-7.4 Common Name Scientific Name
Black Chokeberry Aronia melanocarpa
Red Chokeberry Aronia arubutifolia
American Witchhazel Hamamelis virginiana
American Cranberry Bush Viburnum trilobum
pH 5.0-8.0 Common Name Scientific Name
Sweet shrub Calycanthus floridus
Red Twig Dogwood Cornus alba
Gray Dogwood Cornus racemosa
Arrowwood Viburnum Viburnum dentatum
Nannyberry Viburnum Viburnum lentago
European Cranberry Bush Viburnum opulus


Dangers of Greywater[edit | edit source]

Greywater contains fecal coliforms, albeit at a greatly reduced volume than those present in blackwater, but may still be harmful if ingested. When investigating the homogeneity of the bacterial levels in the combined greywater of a single household over time, Rose et al. (1991) documented large variations of fecal coliform counts (Landry, 1995). During a two and a half-month study, Rose et al. (1991) measured over a 2.5 log fluctuation in the fecal coliform counts (Landry, 1995). As a result it is required by law that no greywater come in contact with edible portions of vegetation, such as lettuce, strawberries, onions, etc. (DWR, 1995). In addition, greywater can also not be allowed to sit for longer than 24 hours, because the bacteria and organisms present in the water will multiply to the extent that it should be considered blackwater. Rose et al. (1991) found total and fecal coliform populations increasing during the first 48 hours of storage and decreasing slowly over the next 12 days (Landry, 1995). Rose et al. (1991) investigated the survival rate of seeded enteric pathogens in [stored] greywater, such as, Salmonella, Shigella, and Poliovirus (Laundry, 1995). The pathogen populations started decreasing in numbers after a two to four day period. After eight days of incubation, population decrease was documented at 1.39 log10 for the Polio virus, which would still represent a health concern (Rose et al., 1991). This makes the storage of greywater for irrigation difficult and requires extensive filtration beforehand or continuous use.

Works Cited[edit | edit source]

General Works Cited[edit | edit source]

  • Anderson, C. (2004). Tap into Water Savings, Enjoy lower water bills; lusher landscapes and longer-lived septic systems when you irrigate with your household graywater. Mother Earth News. No. 205, pgs 100-106. August/September 2004.
  • Engel, J.P. (2004). Selecting Trees and Shrubs for Alkaline Conditions. White Oak Nursery. www.whiteoaknursery.biz. Copyright 2004.
  • Noah, M. (2002). Graywater Use Still a Gray Area. Guest Commentary. Journal of Environmental Health. Vol. 64, No. 10, pgs 22-25. June 2002.

HSU CCAT Grey Water Binders[edit | edit source]

  • Brown, E., J. Freas, and T. Oxford (2002). CCAT Greywater Marsh Water Quality Project. Engineering 305, 2002.
  • Beth, Drew, Nikki, and Stephanie (1997). Grey Water System Analysis of CCAT. Engineering 305, fall semester 1997.
  • California (1991). Graywater Systems for Single Family Residential Occupancies (Draft). State of California AD-HOC Committee on Graywater. December 1991.
  • Camras, D. (1993). Domestic Greywater Reuse: Presentation Summary. Wastewater Reuse Systems NR 515, Humboldt State University. April 27, 1993.
  • Cecil, K. and E. Mattson (2003). Water Quality Analysis of the CCAT Grey Water Marsh. May 7, 2003.
  • Class, D., S. Lim, C. Roberts, and B. Wefso (1993). CCAT Grey Water Treatment System Group Monitoring Project. Engineering 356: Water Quality Analysis. May 14, 1993.
  • Conley, L.M., R.I. Dick, and L.W. Lion (1991). An Assessment of the Root Zone Method of Wastewater Treatment. May-June 1991.
  • DWR (1995). Graywater Guide Book. State of California, Department of Water Resources. January 1995. http://web.archive.org/web/20090820104825/http://www.owue.water.ca.gov/docs/graywater_guide_book.pdf. Site visited 3/27/09.
  • Enferadi, K.M. et al. (1986). Field Investigation of Biological Toilet Systems and Grey Water Treatment. September 1986.
  • EPA (1988). Design Manual: Constructed Wetlands and Aquatic Plant Systems for Municipal Wastewater Treatment. United States Environmental Protection Agency. Chapters 2 and 3. September 1988.
  • Everett, J. and C. Bysshe (1993-1994). CCAT Wetland Project: A Research Project. 1993-1994.
  • Hagberg, T. (1991). The Status of CCAT's Greywater Marsh. Limnology Research Project. May 10, 1991.
  • Ho, G., R. Mars, K. Mathew, and R. Taplin (2003). Greywater Treatment with the Submergent Triglochin huegelii - A Comparison Between Surface and Subsurface Systems. (c) Elsevier Science B.V. Ecological Engineering 20 (2003) 147-156.
  • Ingham, A.T. (1980). Residential Greywater Management in California. State of California, Sacramento, California. January 1980.
  • James, B.B. (1988). Wastewater Disposal in a Forest Evapotranspiration System. January 14, 1988.
  • Kozil, J.D., J.S. Svehla, and J.H Wetzel (2003). Water Quality Evaluation of CCAT's Grey Water System. May 7, 2003.
  • Landry, C. (1995). Design and Construction of a Rock Marsh Greywater Treatment System for the HSU CCAT. Senior project Department of Environmental Resource Engineering Humboldt State University. March 1995.
  • Leppig, G. (1993). Protozoa Concentrations and Diversity in a Residential Greywater Treatment Marsh. Department of Biological Sciences, Humboldt State University. May 17, 1993.
  • Leveille, K. (1995). Design of an Appropriate Greywater System for the HSU CCAT. Senior project to Department of Environmental Resource Engineering Humboldt State University. November 1995.
  • Los Angeles (1991). Plumbing Code Manual No. 1400. Building and Safety Division. Department of Public Works. County of Los Angeles. August 1991.
  • Olkowski, H., B. Olkowski, and T. Javits (unknown). Integral Urban House. Favallones Institute, pgs 97-100.
  • Reed, S.C. and D. Brown (1996). Constructed Wetland Design - the 2nd Generation. WPCF. 1996.
  • Reed, S.C., E.J. Middlebrooks, and R.W. Crites (1988). Natural Systems for Waste Management and Treatment. Chapter 6. 1988.
  • Rose, J.B., S. Gwo-Shing, C.P. Gerba, and N.A. Sinclair (1991). Microbial Quality and Persistence of Enteric Pathogens in Graywater from Various Household Sources. Water Resources. 25 (1), 37-42.
  • San Bernardino (1991). Clear Answers to Using Greywater, Part One. County of San Bernardino. October 1991.
  • Santa Barbara (1990). How to Save Water and Landscaping Safely. Guidelines: Greywater Use in Santa Barbara. April 1990.
  • Santa Barbara (1991). How to Use Gray Water - Guidelines for Santa Barbara County. Santa Barbara County. May 1991.
  • Slattery, C. (1990). Questions About Gray Water. Sunset Magazine, pgs 172-175. July 1990.
  • Steiner, G.R., J.T. Watson, and K.D. Choate (1991). Constructed Wetlands Wastewater Treatment Systems for Small Users Including Individual Residences. General Design, Construction, and Operation Guidelines. Chattanooga, Tennesse. March 1991.


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