Denton Creek Regional Wastewater System

Winner of the following awards:

• AMSA 
  Gold 1997, 1998, 1999, 2001, 2005
  Silver 2000, 2002, 2003, 2004
  　

• Texas Safety Association
  Award of Merit 1997, 1998, 2001, 2003, 2004
  Award of Achievement 2002
  　

• Bowen, Miclette & Britt, Inc.
  Excellence In Safety 1999

This state-of-the-art wastewater treatment plant, located on a 48 acre tract of land north of Roanoke, first began treating wastewater flows in May 1990 using ultraviolet light disinfection units. High intensity light is used in this process to disinfect wastewater flows without the use of chemicals, making the Denton Creek plant one of the first wastewater treatment plants to use this process in Texas. The Denton Creek Regional Wastewater System (DCRWS) serves Fort Worth, Haslet, Roanoke, Southlake, The Circle T MUD No. 1 and 3, Keller, Northlake, Flower Mound, Westlake, and Marshall Creek. Within the City of Fort Worth is the intermodal industrial facility, serving the Alliance Airport facility, which is the first of its kind in the nation providing commercial air

service to many industries, distribution centers and commercial establishments located adjacent to the airport. Also located in Fort Worth is the Texas Motor Speedway, hosting 5-6 race events per year adding to the population of the treatment area 250,000 people per race event with ammonia loadings over 100 mg/l.

Treatment Process Overview / Interceptor System

The Denton Creek Regional Wastewater System includes 25 miles of interceptor  pipelines varying from 15-inch to 36-inch diameter.  There are three major interceptors

in the system.  They are:The Denton-Henrietta Creek  Interceptor, the Fort Worth Trunk, The Cade Branch Interceptor and the Denton Creek Pressure System. DCRWS operates two lift stations and 13 meter stations.

The facility is designed to achieve effluent limitations of 10 milligrams per liter (mg/l)

carbonaceous biochemical demand (CBOD) from December to May and 7 mg/l from June to November, 15 mg/l total suspended solids (TSS), 6 mg/l dissolved oxygen (DO), 2 mg/l ammonia nitrogen in the summer and 5 mg/l in winter.  Daily average flow design is 5 MGD. 

 Denton Creek is an activated sludge single-stage nitrification process followed by tertiary treatment and ultraviolet disinfection. Waste solids are pumped to an aerobic digester and are dewatered by a belt press.

Raw wastewater flows by gravity from the interceptor systems to two Influent Pump Stations. The Influent Pump Stations lift the incoming wastewater from the 
interceptors to the Preliminary Treatment Unit for the removal of large objects, plastic material, and rags. These items are removed by the use of two mechanically cleaned bar/filter screen and one manually cleaned overflow screen. Screenings are dewatered in a screw press located under the bar/filter screen and deposited in a waste container. Following the bar/filter screen,   the flow is directed to a Grit Removal Unit. Grit is pumped by a grit pump from one of the the two collection chambers to the grit cyclone and classifier which discharges the washed grit into the same waste container as the rags. 

The raw wastewater is then sent to one of the three possible treatment streams. Conventional Activated Sludge System, Sequential Batch Reactor or to the Detention Basin.

In the conventional system, the four Aeration Basins mix the activated sludge organisms and air with the incoming wastewater. The organisms consume the conventional organic pollutants in the wastewater. Mixing of the basins is accomplished using diffused aeration and a blower system. The contents of the aeration basins flow into the four final clarifiers. In the four final clarifiers, the activated sludge settles and clarified supernatant overflows to the tertiary system. Floating sludge collectors remove the sludge from the floor of the clarifier, which is deposited into a return sludge trough.     Air lift return pumps return the settled activated sludge to the aeration basins influent where it is mixed with incoming raw influent. Excess activated sludge is wasted with pumps to the Sludge Holding Tank.

The Sequential Batch Reactor is responsible for treating one half of the flow at the facility. The unit is a self contained activated sludge system with one side of the basin operating independently of the other. An equalization basin is designed to handle the effluent from this unit and distribute flows evenly to the tertiary treatment units.

The Detention Basin is designed to handle peak flows relating to race events. This system is a modification of a traditional SBR. Flows to this unit can be treated and released from the basin to the tertiary process or they can be returned and mixed with the raw wastewater for additional treatment.

Effluents from the three treatment process are sent to the tertiary system for final polishing. Two types of tertiary treatment are utilized by the facility. Gravity Sand Filters and Cloth Filter media.   Both units polish the effluent by removing fine suspended particles not removed by settling in the final clarifiers. The sand filters utilize four traveling bridge, low-head, automatic backwash filters. Two are single media and two are duel media filters. The fine solids are trapped in the media and the filtered water passes through the media.  The filter bed is continually cleaned by sections during operation. The cloth filter unit utilizes twelve rotating discs covered by a fine cloth that traps the suspended particles and allows the polished water to flow through the unit. The particles are systematically removed in a backwash process that effectively vacuums the solids from the cloth using submersible pumps. The effluent from the filters flows to the disinfection process.

Solids Handling

 Waste sludge from the Detention Basin and the Activated Sludge units is pumped to an aerobic Sludge Holding Tanks for storage, mixing, concentration, and decanting. 

Trinity River Authority of Texas
Denton Creek Regional Wastewater System
(817) 430-4657

Red Oak Creek Regional Wastewater System

This region wastewater treatment system serves all of Ovilla, Glenn Heights and Red Oak, and portions of DeSoto, Cedar Hill and Lancaster. Capable of serving a population of 35,000, the system consists of a 3.5 mgd treatment plant and 28 miles of pipleline.

TRA's Red Oak plant features a pastoral landscape design. The plant is sheltered from the road any trees  and gently rolling streams. Low intensity lighting, noise control features and an architecturally-designed administration building which resembles a country home helps preserve the plant site's rural character.   Since beginning operations in February 1991, the plant has provided a positive environmental impact on the Red Oak Creek ecosystem.

Trinity River Authority of Texas
Red Oak Creek Regional Wastewater System
(972) 299-6808

Mountain Creek Regional Wastewater System