Wastewater Treatment Plant Permits and Toxicity Reduction Evaluation

Whole effluent toxicity (WET) tests being conducted.

The City of Houston is the fourth most populous city in the nation, with a population of almost two million in a 650-square-mile region. Annually, the City’s wastewater treatment system of 50 treatment plants and 380 lift stations treats over 90 billion gallons of wastewater generated by residential, commercial, and industrial customers (enough to fill the Astrodome over twice per day). PBS&J was contracted by the City to prepare, track, and coordinate Texas Pollutant Discharge Elimination System (TPDES) permits for the 50 wastewater treatment facilities, including renewals, minor and major amendments, and permit transfers. PBS&J has obtained permits for wet-weather facilities, rerated capacities of numerous plants based on influent data, and converted several permits to annual average basis. Biomonitoring efforts for the facilities that have whole effluent toxicity (WET) test requirements include 24- and 48-hour acute tests or seven-day chronic tests for either fresh or saltwater organisms. When confirmed toxicity is determined, PBS&J developed plans acceptable to the Texas Commission on Environmental Quality (TCEQ) for the identification (TIE) and reduction (TRE) of the causative toxicant. With an EPA and TCEQ discharge permit compliance rate of 99 percent, the City has received 28 Gold and Silver Awards from the Association of Metropolitan Sewerage Agencies. The criteria for these awards are no permit violations during the calendar year for a Gold Award and no more than five permit violations during the calendar year for a Silver Award.