Which of the following is a sustainable use of water resources in wastewater management?

Recycling treated wastewater for irrigation is indeed a sustainable practice in wastewater management. This method allows for the reuse of water, which is critical in regions facing water scarcity. By treating wastewater to acceptable standards, it can be safely applied for agricultural purposes. This not only conserves fresh water resources but also reduces the demand for traditional irrigation methods that rely on potable water supplies.

Additionally, using treated wastewater for irrigation can improve soil health and promote sustainable agricultural practices, as it often contains nutrients beneficial for plant growth. This integrates waste management with resource recovery, making it an environmentally responsible approach.

In contrast, the other practices mentioned are less sustainable as they do not efficiently manage water resources or may contribute to environmental degradation. Directly disposing of untreated wastewater into rivers can lead to pollution and harm aquatic ecosystems. Increasing the production of wastewater without effective management strategies can overburden treatment facilities and lead to greater environmental impacts. Building more treatment plants without incorporating recycling channels could lead to increased operational costs and resource waste, rather than optimizing the current water cycle.