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How can treated wastewater be used to irrigate agricultural land?

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Large wheeled irrigation sprinkler sprays water over green crops in a field, with mountains and cloudy sky in the background. — Irrigation Specialized irrigation equipment watering crops in a field.

Treated wastewater can be a valuable resource for agricultural irrigation, particularly in regions facing water scarcity or drought. After undergoing appropriate treatment—typically secondary treatment—effluent can be safely applied to certain agricultural crops to provide necessary moisture and nutrients.123

The application of treated wastewater to land is generally categorized as a form of land treatment. Common methods include:3

Irrigation (Slow-rate): Effluent is applied to the land using ridge-and-furrow spreading (ditches) or sprinkler systems. In this process, the roots of growing vegetation, such as corn or grain for animal feed, absorb most of the water and nutrients.3
Direct Reuse: Treated wastewater is piped directly into an irrigation system, such as those used for golf courses or specific crops, without being diluted in natural water bodies.2

While this practice helps conserve freshwater supplies, its feasibility depends on factors such as climate and soil texture. Additionally, the required level of treatment depends on the intended use, though requirements for agricultural irrigation are generally less stringent than those for potable water supplies.32