AWWA MTC53842

The San Patricio Municipal Water District (District) supplies potable water tonine cities and several water supply corporations located within San Patricio andAransas Counties, Texas. The District also supplies potable, raw, and customerspecific industrial water to several companies. The District operates two adjacenttreatment facilities with a combined treatment capacity of 15 million gallons perday (mgd). Plant A is a conventional water treatment facility that has a capacityof 9.0 mgd. The process consists of coagulation, flocculation, sedimentation, andgranular media filtration. Plant B produces water for one of the Districts' largeindustrial users. The treatment facility has a capacity of 6.0 mgd and consistsof inclined plate settlers and a packaged plant (Microfloc) filtration unit. InMarch 1998, the District initiated the Plant C expansion. The purpose of thisproject was to provide additional water to a new industrial user and to providean additional source of water to serve the growing demand for potable water. Thesource water for both plants is the Nueces River. The primary treatmentobjectives are turbidity and color removal and primary disinfection. An algaecideis applied to the pre-sedimentation reservoir and chlorine dioxide is added justupstream of the rapid mix units to control algae within the sedimentation basins.Primary disinfection is achieved with free chlorine and a combined chlorineresidual is maintained throughout the distribution system. Includes table, figure.