The City of Grand Junction will conduct a mixing zone study this week at the Persigo Wastewater Treatment Plant’s (WWTP) diffuser structure located in the Colorado River. The study is scheduled to take place from Tuesday, August 5, to Thursday, August 7, 2025, and will involve the use of a non-toxic, biodegradable fluorescent dye specifically designed for environmental testing.
While the dye is safe for humans, fish, and other aquatic life, it may temporarily discolor parts of the river near the diffuser structure. The treated water released from the Persigo WWTP accounts for less than 5% of the Colorado River’s flow. The diffuser structure helps ensure rapid mixing of the treated water with river water.
This study is an important milestone in confirming the diffuser system’s effectiveness. It also reflects the City’s ongoing commitment to protecting water quality and serving as a responsible steward of the Colorado River.