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Texas Department of Criminal Justice

Year Submitted: 2010

Process: Wastewater Treatment

Industry: Prison

Wastes Reduced: TSS, CBOD-5, Nitrogen Ammonia

Location: Huntsville TX

No. of employees: 593

Contact: Howard W. Gray

Phone: 936-437-7240


The goal of the project was to improve the performance of the wastewater treatment facility. To do this, the engineer designed a continuous backwash down-flow treachery filter. The facility's permitted total suspended solids (TSS) discharge limit decreased from 15 mg/L to 5 mg/L. After completion in November 2006 the filter did not achieve the required performance initially. The operator and Wastewater manager worked on operational problems and maintained the permit requirements by using chemical flocculation. After hundreds of flow data samples and completion of the hydraulic profile of the system during problem periods, waste line from the sand wash tube was found to be the problem. The water level was raised to within 2 above the waste line and not allowed to go over 12 above the waste line. This stabilized the operation allowing the discharge effluent to have a TSS concentration of less than 5 mg/L.

P2 Application:

The engineer designed a continuous backwash down-flow treachery filter to allow the treatment facility to avoid chemical flocculation. The filter was constructed by TDCJ in-house personal. The new technology was functional but not as designed. Two operators dedicated themselves to determine where the failures were occurring using scientific means. This was a combination of qualified wastewaters operators who understand the biological process, the scientific means to obtain the information and the mechanical knowledge to make the needed corrections.

  • Comments: The overall cost of the project was $984,000. The overall project improved the screening process allowing a clean facility and smooth operation. Pumps have not had any trash clogs since the project was completed. The environmental liability reduced (permit effluent exceedances) to zero. The filter and the components have an estimated life of twenty five years. The air compressor has a five year life span. The operational costs compared to other filters acquiring the same results are much lower. Media in other types of filters are replaced at regular intervals, but the media used in this filter should last the life of the filter itself. The water discharged from this facility will be cleaner than is required and will enhance the water quality in the Trinity River.

Details of Reductions

  • 6,957.0 - lbs of   Total suspended solids
  • 8,856.0 - lbs of   CBOD-5
    Comments: CBOD-5 = Carbonaceous Biological Oxygen Demand (Strength of the sewage)
  • 1,060.0 - lbs of   Nitrogen Ammonia

Additional Information :

The filter was built in-house, started on 2/1/2005, and completed on 11/1/2007. Cooperation was internal between another facility's laboratory, our facility operator, and the wastewater manager in headquarters. Samples, flow readings, mixed liquor levels were all documented at the same time. Several months of data were acquired and used to determine where the break-through was occurring. The functioning filter has allowed the TDCJ to operate the facility within the compliance parameters and allowed the facility to maintain compliance to date. Laboratory testing is done on the effluent by an EPA in-house laboratory. Annual average flow is 0.6 MGD. The annual average TSS in 2005 was 8.809 mg/L. Calculated out about 16,089 lbs were discharged during 2005.The last twelve months the facility has discharges less than 5 mg/L. Calculated out at 5 mg/L TSS, 9,132 lbs were discharged during 2007/2008 twelve month period.

Source: TCEQ
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