Application 4 / 5
Environmental Protection
Humic substances bind metal ions and some organic compounds, which is why they are studied and used in water treatment and in the remediation of contaminated soil. The pages below explain where they are used and their limits.
Four topics
Where humic substances are used in environmental work
Water treatment
Natural humic substances are a common part of surface water, and in drinking water treatment they are mainly a constituent to remove, because they colour the water and react with chlorine to form disinfection by-products. Humic-based materials are also studied as sorbents and coagulant aids that bind metal ions; whether they suit a given water depends on its chemistry and the treatment train.
What to check
- Organic carbon added to the water
- Metal binding at the water’s pH
- Interaction with disinfection
Wastewater treatment
In industrial wastewater, humic acid and humates have been studied for binding heavy metals and some dyes and for conditioning sludge. Results depend on the effluent, its pH and salinity, and are confirmed in bench and pilot tests before use.
What to check
- Removal in bench and pilot tests
- pH and salt tolerance
- Fate of the bound contaminants in the sludge
Soil remediation
Humate amendments are used in remediation to bind metals and some organic contaminants in soil, and soluble humates are studied as washing agents that help extract contaminants. The choice between binding and extraction depends on the site, the contaminant and the remediation goal.
What to check
- Contaminant type and concentration
- Soil pH, texture and organic matter
- Monitoring after treatment
Heavy metals in soil
Humic substances form complexes with heavy metals. Insoluble humic acid tends to hold metals in the soil, while soluble fractions such as fulvic acid can increase their mobility, so the net effect depends on the product, the dose and soil conditions. It is assessed with soil and plant analyses rather than assumed.
What to check
- Soluble and total metal content
- Changes in metal mobility over time
- Plant uptake in field or pot tests
What to check
- Which fraction is used: humic acid (insoluble) or soluble humate / fulvic acid
- Heavy metal content of the humic product itself
- Trial design, controls and monitoring
- Local regulations for remediation materials
Guides
Planning a remediation or treatment trial?
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