How Safe is Grey Water for Irrigation?

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How safe is it to use greywater for irrigation purposes? Does someone has a practical case to share? 

We are thinking of using greywater after treatment for irrigation purpose. 

What is the easiest and cheapest method to make it suitable for irrigation?  

 

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30 Answers

  1. The suitability of recycling (i.e. application without treatment) greywater for irrigation purposes depends on many factors.  In a single-family residential application, using greywater collected from bath, shower, lavatory, and laundry drainage, the greywater could be applied or poured onto the soil with little health or environmental risk.  While it is possible the water could contain disease causing microorganisms shed from the body or soiled laundry garments, there is a greater probability of transferring disease within the family due to personal contact and food preparation.  In North America, where Health agencies permit greywater to be used for irrigation without treatment, untreated greywater is normally only allowed to be used for landscape irrigation (i.e. non-food vegetation) if applied below the surface of the soil.  The rationale is to prevent the greywater from coming into direct contact with humans (kids, gardeners, etc.).

    In developing national water reuse guidelines (2012), Health Canada initially considered only greywater sources - under the premise that greywater was somehow inherently  a lower health risk than mixed wastewater.  However, their risk assessment analysis concluded there was no significant benefit to considering only reclaiming greywater.  The types of contaminants present - including potential for disease causing bacteria, parasites and viruses - were similar for both greywater and mixed wastewater, and the technologies used to treat both were identical.  

    Back to your question, the least expensive method of irrigation with greywater is surface distribution, taking into consideration the source of greywater and the potential for disease transmission due to human contact with the water before it enters the soil.  Bacteria naturally present in the soil will rapidly biodegrade the organics present, and natural processes will remove any pathogens that may be present in the greywater.  If the soil is subject to at least seasonal fresh water infiltration as a result of rainfall, any salts that otherwise may accumulate and adversely affect soil structure will be flushed out.  Some plants may be sensitive to the soaps, detergents in greywater, and/or the pH of the water - so that should be a consideration in assessing suitability for a specific application. 

    Constructed wetlands are commonly used to treat domestic wastewater, which typically consists of more than 60 percent greywater without adversely affecting the plants.  The plant roots are in constant contact with the wastewater, including greywater components, and the plants thrive on the nutrients present.

    http://nepis.epa.gov/Exe/ZyPDF.cgi/30005UPS.PDF?Dockey=30005UPS.PDF

     

  2. Hi

    in order to reuse gray water for irrigation,  subsurface drip irrigation (SDI) is a must, due to the fact that soul will act as a buffer to absorb some of the aroma in gray water. In order to properly use SDI, a 130 micron filtration to remove solids will be needed and of course a specially designed dripper line for this purpose. Dripperlines should be properly maintained on a regular basis with acid treatment and peroxid if organic matter is found on such water 

  3. Hi

    in order to reuse gray water for irrigation,  subsurface drip irrigation (SDI) is a must, due to the fact that soul will act as a buffer to absorb some of the aroma in gray water. In order to properly use SDI, a 130 micron filtration to remove solids will be needed and of course a specially designed dripper line for this purpose. Dripperlines should be properly maintained on a regular basis with acid treatment and peroxid if organic matter is found on such water 

  6. Good day, Michael ! If You want to see how it is done and what is the result - come to us. We have a customer after our clean-handed 8 kilometer pipeline that would water after cleaning is not lost and watered with crops. He even began to save money on fertilizer, because the water regenerates the soil and no need to use chemicals. The yield ( according to him ) have increased by 20 to 25%. So welcome !!! e-mail tumentsevs@gmail.com

  7. It all depends on how do YOU clean waste water. What method, to what extent. We used water after treatment for irrigation - and the results yield increased by 25%. But we do not purify the water using biological methods. WE have developed their own cleanup method , which is simpler biological, its more effective and less energy-consuming. The costs of wastewater treatment as our technology is FOUR times less than traditional cleaning methods . Supplying water for irrigation can be obtained and additional income, which will reduce the cost of purification, and thus will give additional revenue. YOU would do do it . It will be reused water.

  9. As long as the entire system is underground most authorities will permit reuse of almost any quality of greywater.  Geoflow, Netafim and Rainbird all offer a special tube protected from root intrusion for subsurface drip irrigation.  

  10. Hi, sir my organisation working in irrigation sector, can you provide detail information about your water on my mail,we are definitely provide cheapest solution for gray water use for irrigation.

    Thanks and regards

    Vishal 

    Design13@jains.com

  12. The new surge of nanotechnology brings a lot of unknowns into play in use of grey water of varying quality. Also, Google BMAA toxin to learn of cyanobacterias toxins that might, under some circumstances, become present in water yet not tested for. How many nanometals might be present? Some toxicants, if present at only the ppt levels can be significant health-limiting risk. How many do we NOT test for?

    Answered on by

    1 Comment

    1. Of course the surge of nanotechnology opens up many unknowns. And they need to learn. So let us do it together. We are now seven years clean drains livestock and purified water pour field for grain. Productivity increased by 25%. If You want to check some options - we invite You and interested parties to us. You can analyze the state of purified water and "contamination" of the soil , especially those that then add in the ground in the form of mineral fertilizers. Can also check the condition of the water in the sea, where the discharged waste water - what is there positive effect of drains.

  14. Will any humans come into contact with the gray water?  Where did the gray water come from and do you know what detergents, chemicals or contaminants it might have in it? Is it from home uses?

  15. Hi,

     

    We work with a specific mineral complex consisting of 100 minerals in ionic form, which purify over 250 toxins, including bacteria, viruses, heavy metals, pharmaceuticals, and other chemicals from water. They can be used to restore water to be drinkable, and of course clean (and beneficial) for irrigation. One must understand that the building blocks of life are minerals, and when using a full matrix of minerals in irrigation water, plants, soil, and consequently live stock and humans highly benefit. The cost can be as low as 0.009 cents per liter of irrigation water.

    Feel free to review this page and contact me should you have any additional questions.

    1 Comment

    1. This interests me greatly as well. Please send me info to gordon@gurumanzi.com. We are using Hydrochemical Activation to treat grey water and highly contaminated river and dam water. Any further beneficiation of the treated water for agricultural/irrigation purposes or for potable purposes is sought.

  16. Water quality sampling, analysis, and assessment of potential risks, is still in its infancy and is dependent on testing science that does not include adequate capability to detect a wide range of greywater contaminants.... just because a testing entity states that they have tested for a suite of chemical contaminants does NOT mean that there were not other chemicals in that water that were not tested for... and go undetected.

    We have created about 85 thousand chemicals, largely new to the world environment, released as ingredients in products to spread around the world to eventually degrade into water pollution. Many of these have adverse effects potentials at chronic low dose levels that can even be accumulative in nature. Very few are EVER included in actual testing of greywater. You don't often find what you don't look for with a high degree of scientific integrity intent.

    As always it is 'buyer beware'. We really know very little about all of the potential chemicals that could be present in any given greywater, we don't even have adequate tests developed to test for them all even if we knew we needed to. We DO NOT do testing that is logically and scientifically sufficient to assert with unfailing confidence the 'safety' of greywater.

    We can only say, after our modest testing, that we think that we have done due diligence in testing.... but our inadequacies of testing abilities and assessments remain less than what is scientifically adequate. Politics, and profit margin pressures,  step in to limit the testing process to very little actual analysis. It is all relative, and we DO need to use water at some point, so we just do what testing we usually rely on and let it go at that.... but the real science of it remains hidden behind a screen of what we have not yet learned. Buyer beware.

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    1 Comment

    1. Yes, we don't know much, I'm afraid to apply the new, clinging to the old, drawing on the experience of previous years, because no history new. Therefore, we chlorinate the water, knowing that the accumulated chlorine is the source of a large number of diseases, including cancer. Let's get together I'm afraid the new ... and drink water with bleach ..

  17. Dear Friends,

    Let us make one thing clear, it is scientifically proven that no bacteria or organic pathogens can be absorbed through the plant roots and go in to fruit or leaves, etc. 

    Therefore there is no problem with using organic in origin grey water if you do not spray it on the plants but rather deliver it through the roots.

    Using bio filtration and a bit of polishing with ozone you could turn grey water in to a drinking water.'

    Here is 35 second video of the system that does exactly that:

    http://absoluteozone.com/ozone-generator-wastewater-treatment.html

    I agree with people who state that grey water containing dangerous chemicals is not suitable for irrigation without serious treatment that will make it safe.

     

  18. Hi Lehlogonolo Motsoko  how are you today?, I know a project called fossa biodjestora, I think that is possible to use gray water with this project.
    Have a great day!!

     

  20. If water has untreated sewage, or partially treated sewage it will be not fit for irrigation. If the grey water does not have any sewage 0%!!,it should be tested by a water lab to check the presence of salts, Ca, Na, Cl,  SO4,  Mg,  HC03, CO3. When these are present they may cause problems with the soil as well as affecting crops.

    Grey water may be used for golf courses, parks or lawns  but still checked for salts.

     

  25. Greywater is not really any safer for irrigation than blackwater. It still carries faecal matter and more so if their is illness in the occupants. The high solids content in the water even if filtered prevents successful disinfection. It can be used safely with drip or flood irrigation on tree and vine crops where water does not come in contact with the fruit or nuts. There should be a withholding period of 3-7 days before harvest where no irrigation is carried out.

    Answered on by

    1 Comment

    1. There are a lot of difference between black water  and grey water from pollution point of view in spite of grey water not safe condition but it has less  hazard pollution matrix such as   stool , worm egg ,bacteria ,virus and  .. etc .Its treatment has less complexity than black water .

  27. The cheapest way for reusing of grey water is wetland construction as decentralized local bio remediation  for  removing of hazard substance in grey water  particular in rural and remote area without need to electricity and large utilities. 

  29. Dear Lehogonolo,

    It depends!  

    Source of greywater.

    Treatment of greywater.

    Crop being irrigated. 

    If it is not a root crop being eaten raw then subsurface drip irrigation reuse can handle most situations and due to the recent droughts is now widely used in California.

    See www.californiawaterreuse.org.  and the bottom section of  http://www.geoflow.com/Library/libraryag.html 

    I have a close connection with South Africa and in the late 1960's, with Charel van Schoor, was the co-founder of Agriplas.  Agriplas has access to our technology through Metzerplas who are licensees of our technology.

    Regards,

    Rodney

     

     

  30. Hi,

    Here's a webpage I found helpful regarding the use of greywater for irrigation. Apart from what is mentioned about salts, keep in mind that a frequent water, soil and crop monitoring is crucial when using greywater for irrigation mostly to study the nutrient balance and the required leaching fraction (if any) as well as any possible dilution.

    http://greywateraction.org/contentabout-greywater-reuse/

    Best,

    Ramy