Humic acid, dextran, and valeric acid representing macromolecules similar to compounds prevailing in treated wastewater induce soil hydrophobicity

Shai Tolkin, Yona Chen*, Jorge Tarchitzky

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: Organic compounds originating from treated wastewater and soil texture have been reported to be the dominant factors influencing soil hydrophobicity. It is the aim of this investigation to elaborate the role of humic acid, dextran, and valeric acid, representing dissolved organic matter, polysaccharides, and fatty acids, respectively, as well as imitating their activity in inducing soil sub-critical water repellency induced by treated wastewater irrigation. Materials and methods: The relationships between three model compounds imitating fractions of dissolved organic matter commonly found in treated wastewater, soil texture in relation to water repellency, were investigated. Three types of organic molecules, five soil mixtures with different specific surface areas, and three different organic compounds, as well as a mixture of the three, were tested. Results and discussion: After 14–15 of wetting and drying cycles, low levels (sub-critical hydrophobicity) of water repellency developed in all soil mixtures were subjected to applications of several solutions of organic compounds, in comparison with a freshwater control. The highest degree of water repellency was exhibited by the soil with the lowest clay content (lowest specific surface area) and it decreased with increasing clay content (increasing specific surface area). Conclusions: The order of intensity of sub-critical water repellency levels induced by the organic compounds was consistent, yet independent of soil texture. However, soil texture exhibited large influence on soil hydrophobicity in response to the various organic chemicals. Humic acid, the closest in structure to organic matter prevailing in treated wastewater, exhibited the largest effect in inducing soil hydrophobicity.

Original languageEnglish
Pages (from-to)3548-3556
Number of pages9
JournalJournal of Soils and Sediments
Volume20
Issue number10
DOIs
StatePublished - 1 Oct 2020

Bibliographical note

Publisher Copyright:
© 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

Keywords

  • Humic acid
  • Polysaccharides
  • Soil wettability
  • Water drop penetration time (WDPT)

Fingerprint

Dive into the research topics of 'Humic acid, dextran, and valeric acid representing macromolecules similar to compounds prevailing in treated wastewater induce soil hydrophobicity'. Together they form a unique fingerprint.

Cite this