Discharge Permit of Tomorrow: Integrated Permitting of San Antonio’s Water Recycling Centers

摘要

In 2002 the San Antonio Water System (SAWS) completed start-up of the nation’s largest recycled water delivery system. To reduce dependence on the Edwards Aquifer, and in support of State Water Plan objectives for reuse and conservation, it delivers 35,000 acre-feet per year to industrial and commercial customers and streamflow augmentation discharges on the San Antonio River and Salado Creek. To create maximum reliability and water supply redundancy, interconnections within the recycled system and between the plants that supply recycled water are under construction. Effluents for stream discharges will originate at different facilities and be commingled. However, permitting rules did not contemplate that such a system could exist. SAWS is asking the State of Texas and EPA to consider a new permitting paradigm that authorizes multiple commingled discharges and emphasizes the managing of mass loadings. The ‘integrated municipal permit’ approach supports Texas’ objective of TMDL watershed management and EPA’s new policy of watershed-based NPDES permitting. It will provide operational flexibility and greater environmental protection and pave the way for development of effluent reuse systems that have concurrent goals of non-potable reuse and environmental restoration through streamflow augmentation. Once approved, this integrated permit will set a new national standard for municipal wastewater discharge permits.