Using treated graywater for irrigation is better for arid environments

July 12, 2017
Credit: Mick Lissone/public domain

Reusing graywater in dry areas may require treatment for more efficient irrigation in arid, sandy soils, according to a new study published in Chemosphere by researchers at the Ben-Gurion University of the Negev (BGU) Zuckerberg Institute for Water Research. Graywater includes any wastewater generated in households or office buildings except from the toilet.  

Graywater use has been proven safe for agriculture irrigation. "Most of the scientific research and legislation efforts have focused on graywater's health risks, while less attention has been given to its environmental outcomes, including its effect on soil properties," says Prof. Amit Gross, head of the Department of Environmental Hydrology and Microbiology in the Zuckerberg Institute.

Prof. Gross and his team found that graywater does not infiltrate through the soil as easily as fresh water and is slower to reach plant roots. It can also cause water runoff leading to erosion.

"This condition, called 'graywater-induced hydrophobicity,' is likely temporary and disappears quickly following rainwater or freshwater irrigation events," says Prof. Gross. "However, it is a more significant concern in with negligible rainfall as compared with wetter regions."

According to the researchers, treating the graywater using biofiltration to degrade the hydrophobic organic compounds will eliminate the problem.

In the study, the researchers examined how graywater induces soil hydrophobicity, as well as its degree and persistence. They created three graywater models using raw, treated and highly treated graywater to irrigate fine-grained sand compared to a freshwater control. The result was that only the raw graywater irrigated showed hydrophobicity, which could be mitigated with both moderately and highly treated solutions.

"Onsite reuse of graywater for irrigation is perceived as a low risk and economical way of reducing freshwater use and, as such, it is gaining in popularity in both developing and developed countries," says Prof. Gross. "As many government authorities are establishing new guidelines, the results of this study reinforce the recommendations to treat graywater before reusing for , particularly in arid regions."

Explore further: Stormwater and graywater offer alternative water sources, but guidelines needed on their safe use

More information: Adi Maimon et al, Greywater-induced soil hydrophobicity, Chemosphere (2017). DOI: 10.1016/j.chemosphere.2017.06.080

Related Stories

Greywater reuse for irrigation is safe

December 16, 2015

Researchers at the Zuckerberg Institute for Water Research at Ben-Gurion University of the Negev have determined that treated greywater is safe for irrigation and does not pose a risk for gastrointestinal illness or water-related ...

Climatic effect of irrigation over the Yellow River basin

April 21, 2017

As a sensitive region of global climate change, the Yellow River basin, situated in arid and semiarid regions, also plays an important role in food production. However, using water resources in the Yellow River basin is challenging ...

Germs in wastewater often become airborne

October 13, 2016

Using household wastewater to irrigate food crops in drought-stricken or arid regions isn't the perfect solution. The chemicals and disease-causing germs it might contain could contaminate crops. Viruses that have their origin ...

The cooling effect of agricultural irrigation

April 12, 2017

Previously, scientists have suggested that agricultural irrigation affects mean climate in several regions of the world. New evidence now shows that this cooling influence is even more pronounced when it comes to climate ...

Tech revolution ends up in the toilet

July 9, 2012

It's one of the most critical pieces of technology in your home. And though most consumers don't think of their humble toilet as a tech product, researchers and engineers at global companies are racing to improve designs ...

Recommended for you

New Amazon threat? Deforestation from mining

October 18, 2017

Sprawling mining operations in Brazil are destroying much more of the iconic Amazon forest than previously thought, says the first comprehensive study of mining deforestation in the world's largest tropical rainforest.

Scientists determine source of world's largest mud eruption

October 17, 2017

On May 29, 2006, mud started erupting from several sites on the Indonesian island of Java. Boiling mud, water, rocks and gas poured from newly-created vents in the ground, burying entire towns and compelling many Indonesians ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.