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Treated Graywater Is Better for Irrigation

Treated Graywater Is Better for Irrigation

July 12, 2017

Desert & Water Research, Press Releases

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 in agriculture irrigation has proven safe for consumption. “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 arid lands with negligible rainfall as compared with wetter regions.”

Prof. Amit Gross

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 soil 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 irrigation, particularly in arid regions.”

Other researchers who collaborated on the study were Ph.D. candidate Adi Maimon of the Department of Environmental Hydrology and Microbiology and Dr. Arye Gilboa of the French Associates Institute for Agriculture and Biotechnology of Drylands.

Together with the Swiss Institute for Dryland Environmental and Energy Research, the institutes comprise BGU’s Jacob Blaustein Institutes for Desert Research on its Sde Boker Campus.

ABOUT AMERICANS FOR BEN-GURION UNIVERSITY

By supporting a world-class academic institution that not only nurtures the Negev, but also shares its expertise locally and globally, Americans for Ben-Gurion University engages a community of Americans who are committed to improving the world. David Ben-Gurion envisioned that Israel’s future would be forged in the Negev. The cutting-edge research carried out at Ben-Gurion University drives that vision by sustaining a desert Silicon Valley, with the “Stanford of the Negev” at its center. The Americans for Ben-Gurion University movement supports a 21st century unifying vision for Israel by rallying around BGU’s remarkable work and role as an apolitical beacon of light in the Negev desert.

About Ben-Gurion University of the Negev

Ben-Gurion University of the Negev embraces the endless potential we have as individuals and as a commonality to adapt and to thrive in changing environments. Inspired by our location in the desert, we aim to discover, to create, and to develop solutions to dynamic challenges, to pose questions that have yet to be asked, and to push beyond the boundaries of the commonly accepted and possible.

We are proud to be a central force for inclusion, diversity and innovation in Israel, and we strive to extend the Negev’s potential and our entrepreneurial spirit throughout the world. For example, the multi-disciplinary School for Sustainability and Climate Change at BGU leverages over 50 years of expertise on living and thriving in the desert into scalable solutions for people everywhere.

BGU at a glance:  

20,000 students | 800 senior faculty | 3 campuses | 6 faculties: humanities & social sciences, health sciences, engineering sciences, natural sciences, business & management, and desert research.

 

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