The Rowlett Creek Center is a Trickling Filter/Activated Sludge (TF/AS) plant permitted to treat 24 million gallons per day (0.09 m3/d). The Texas Commission on Environmental Quality (TCEQ) limits discharge of treated wastewater that contains not greater than 10 milligrams per liter (mg/L) of carbonaceous biochemical oxygen demand, 15 milligrams per liter (mg/L) total suspended solids and seasonal ammonia nitrogen limits of 5 milligrams per liter (mg/l) (December - March) and 2 milligrams per liter (mg/l) (April - November).
Treated effluent is discharged into Duck Creek, then to the East Fork of the Trinity River, and ultimately to the Trinity River before being discharged into the Houston ship channel. During dry months, the river may be composed of up to 95 percent wastewater, and performance of the Rowlett Creek Plant is critical to the Trinity's health and usefulness as a drinking water source for those downstream.
All biosolids (sludge) precipitated at the Duck Creek and Rowlett Creek Plants are processed at the Rowlett Creek Plant with ultimate disposal in the City of Garlands' landfill.
For the year 2011, the Rowlett Creek Center treated an annual average of 17.64 million gallons per day (0.067 m3/d) of effluent wastewater. The Rowlett Creek Plant has performed well. The facility has received several Gold and Silver Awards from the National Association of Clean Water Agencies (NACWA) in recognition of its complete and consistent national pollutant discharge elimination system permit compliance. Tours are given often to local, national and international visitors.
In its quest to excel, several capital improvements projects of note include a flow transfer pumping station, gravity belt solids thickeners, and additional plant nitrification improvements.