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Tuesday, April 20, 2010

Greywater & World Water Day

Free Peer-Reviewed Articles on Greywater!

To show its support of World Water Day 2010, Routledge, in collaboration with editors and society partners, have selected research articles and special issues which engage with the UN World Water day themes of; sustaining healthy ecosystems, increasing water quality, access to clean water and contemporary challenges in water management. These articles are available free until the 23rd April 2010. 

They would also encourage you to pass this offer on to any colleagues or organisations that you work with that you think would benefit from completely free access to this research.

For access to a journal dedicated to greywater please visit http://www.informaworld.com/smpp/title~db=all~content=g790726970

Access the free articles here.

"In the era of water scarcity and climate change, the world must become water-wise. Greywater can be a cost-effective alternative source of water in arid and semi-arid countries. It can be used to promote sustainable development and resource conservation without compromising public health and environmental quality. And yet, treated greywater reuse is not widely adopted in most countries. This paradigm of water management ought to shift towards a new one, which aims to provide adequate amounts of water of acceptable quality. Use of treated greywater for irrigation, landscaping, car washing and toilet flushing will reduce pressure on freshwater reserves, minimize financial costs of treating waste water and possibly increase income of peri-urban farmers. We hope that through this special issue we may make known the existing wisdom and persuade others to accept its economic value. There is no doubt that this is the future" (emphasis added).

Some interesting articles on kitchen sink wastewater and pathogen and bacteria survival that might surprise some.  Wake up Oregon.


  1. The article on pathogen lifespan was interesting, but I suspect the experiment was flawed.

    The tests were conducted using bare soil (without vegetation) and therefore is very possible that the upper 3-4" of the soil did not contain much beneficial bacteria, and certainly not plant roots etc.

    So while the 7 day lifespan is interesting, it is most likely far less in a properly installed graywater system benefitting from a an active soil.

  2. Paul:

    Thanks for these comments. Recalling that the Oregon Graywater Advisory Committee was hesitant to accept information regarding survival and risk posed by micro-organisms, I thought this journal might dispel some of the myths. Your point is well taken.

    I found the following information in another journal article where they were looking at *worse case* scenarios - spreading of municipal sludge. Some of the findings:

    1. "It has been observed that the survival of the micro-organisms is lower in summer and in sandy soils (rather than clay), and when sludge is spread on the soil surface rather than injected (as in the case of septics or UIC)".

    2. "Some of the conditions under which this experiment was conducted were favourable for an increase in the survival of the micro-organisms since sludge was injected into a wet soil, in autumn, at relatively low temperatures (between 4.5 and 15 degrees C). On the other hand, the nature of the soil, being sandy, and low in organic matter, will have had a negative effect on the survival of the micro-organisms".

    3. "In spite of the low temperatures observed during the period of the study, which are known to improve the survival of viruses, the enteroviruses were still quickly inactivated after spreading. This disappearance of the viruses can be explained partly by the microbial activity of the soil".

    Pourcher, A., et al, 2005, Survival of faecal indicators and enteroviruses in soil after land-spreading of municipal sewage sludge. Applied Soil Ecology 35 (2007) 473–479.

    Bottom line. Micro-organisms of concern in greywater and "blackwater" have a tough time surviving for very long in the real world.

  3. What I do find interesting re some states is that they are prepared to allow mulch basins (ie grayvity) without permits, but require permits for a pressurized system. There is clearly more contamination risk from mulch basins as a result of concentrated graywater dispersal in a relatively small number or areas, hence overloading bacteria.