Onion Creek WRP - Advanced Wastewater Treatment in Bastrop County, Texas

Onion Creek WRP is an advanced wastewater treatment facility located in Bastrop County, Texas, United States. It serves a population of approximately 2,300 residents, providing essential sanitation services to this rural community east of Austin. The plant employs advanced treatment processes, which go beyond secondary treatment to remove nutrients and other pollutants. With a designed capacity of 1,305.96 megaliters per year and an annual discharge volume of 757.08 megaliters, the facility operates well within its capacity. As a US plant, it operates under the Clean Water Act, with National Pollutant Discharge Elimination System (NPDES) permits issued by the Texas Commission on Environmental Quality (TCEQ). The treated effluent is discharged into the local watershed, which ultimately drains into the Colorado River of Texas and then to the Gulf of Mexico. The plant plays a key role in protecting water quality in the region, particularly in the context of the Edwards Aquifer recharge zone and the sensitive downstream ecosystems of the Colorado River basin.

The plant discharges into the Onion Creek watershed, a tributary of the Colorado River of Texas. The Colorado River flows southeast through the Texas Hill Country and eventually empties into the Gulf of Mexico at Matagorda Bay. This region supports diverse aquatic life and is an important corridor for migratory birds. The advanced treatment helps protect downstream water quality, particularly in the ecologically sensitive Edwards Aquifer recharge zone.