Which method is least likely to be used for treating high-strength industrial wastewater?

Land application is the method least likely to be used for treating high-strength industrial wastewater due to several important factors. High-strength industrial wastewater typically contains elevated concentrations of pollutants, including organic compounds, heavy metals, and toxins, that may exceed the capacity of soil and groundwater to naturally absorb and treat these contaminants.

Land application generally relies on the natural processes of soil microorganisms and vegetation to treat wastewater, which may not be effective in managing the high levels of pollution found in such wastewater types. Additionally, there are regulatory and environmental concerns associated with contaminating land and potentially impacting nearby water sources or ecosystems.

In contrast, biological treatment, chemical treatment, and physical treatment are more commonly employed methods for high-strength wastewater. Biological treatment utilizes microorganisms to breakdown organic material, making it effective for organic-rich waste; chemical treatment involves adding chemicals to neutralize or precipitate harmful substances; and physical treatment, which may include processes such as filtration and sedimentation, can be used to remove solids and particulates efficiently.

This inherent limitation of land application in handling the complex composition and high pollutant load of industrial wastewater makes it less feasible compared to the other treatment methods.