City of Lufkin, 300 E. Shepherd
Lufkin, Texas 75902 936-634-8881

Wastewater Treatment
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Wastewater Treatment

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Plant Description



Wastewater Treatment Plant
Phone Number: 936-633-0288
Emergency Number:

  • The staff of the WWTP is available for school tours of the facility. For any questions or information regarding the City's WWTP, please call (936) 633-0288
  • Free RV Dump Station Monday through Friday 8 am to 4 pm. Saturday use may be available if the owner has made arrangements during the previous week.
  • The Industrial Pretreatment Program is conducted from this department. Any questions or comments concerning the Program can be directed to the Environmental Manager by calling (936) 633-0288.

The Process of Wastewater Treatment


Sewage discharge from Lufkin's residential, commercial and industrial contributors is collected at the WWTP. The influent sewage is pumped into the Plant and introduced to forced air, which will increase the microbial activity and aid in the removal of grit and grease.

The influent enters a separation stage of solid settling. The untreated sludge is Primary Sludge. It is thickened and then pumped to a Holding Tank which also receives thickened Secondary Sludge. The Holding Tank Sludge is pumped to three Anaerobic Digesters and held for a minimum of 15 days at 100°F to 105°F. The Anaerobic Sludge is hauled to a state permitted application site for beneficial use and also to the county landfill.

The Primary water flows to the Aeration Basin. This is the heart of the treatment plant. The Primary water is introduced to forced air and Secondary Sludge being returned from the Final Clarifiers. The Primary water provides food, the Secondary Sludge provides microorganisms and the air provides respiration for the microorganisms. In the Aeration Basin, or Biological Reactor, the waste is broken down by the microorganisms into a stable inert form. The Secondary Sludge from the Basin is pumped to the Final Clarifiers where it is allowed to separate the solids from the water. Part of the solids are returned to the Aeration Basin as food and the rest is thickened by the Gravity Belt Thickener then pumped to the Holding Tank. The clear water, or Effluent, is sent to the Chlorine Contact Chamber where it is held in the presence of chlorine to kill the microorganisms. The Effluent is then introduced to sulfur dioxide which removes the chlorine before it is discharged into Hurricane Creek.


                        Plant Design Criteria:

                             Conventional Waste Activated Sludge Plant

                             Design Flow:            11.3 Million Gallons per Day

                             Peak Flow:              11,875 Gallons per Minute


                             Plant Performance:

                             Average Flow 2005:  6.4 Million Gallons per Day

                             Average CBOD 2005: 6 mg/L; 97 % Removal

                             Average TSS 2005:   8 mg/L; 95 % Removal

                             Annual Cost 2005:    $0.758 per 1,000 Gallons Treated

TCEQ Permit Effluent Parameters - 30 Day Avg.

Carbonaceous Biochemical Oxygen Demand (CBOD)

10 mg/L

Total Suspended Solids (TSS)

15 mg/L

Ammonia Nitrogen

3 mg/L

Total Chlorine Residual (Effluent)

1.0 mg/L

De-Chlorination (Creek)

<0.1 mg/L

Dissolved Oxygen

5.0 mg/L


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