AWWA WQTC65856

The Sweeney Water Treatment Plant (SWTP), which receives water from the Cape Fear River and has a rated permitted capacity of 27.5 mgd, serves approximately 35,000 customers in the city of Wilmington, North Carolina. The original portion of the plant, constructed in 1943, and expanded in 1958 and 1978, is a 15 mgd conventional surface water treatment plant. The most recent expansion to 25 mgd (later up-rated to 27.5 mgd), which took place in the mid-90s, included the addition of pre-ozonation, upflow clarification, intermediate ozonation, and biological filtration facilities. Black & Veatch is designing an expansion and upgrade of the SWTP to 35 mgd, which could be up-rated to 44 mgd. The improvements include replacement of the 15 mgd conventional plant with two upflow clarifier trains, ten new biological filters, and the addition of ultraviolet (UV) disinfection. The expansion also includes upgrading the ozonation facilities, which is the focus of this paper, and includes: evaluation of the hydraulic capacity of the existing contactors; modification of the ozone dissolution systems to improve ozone delivery and maintainability of the equipment; and, evaluation and optimization of the ozone dosages to be delivered by the preozonation and intermediate ozone systems to determine capacity of the ozone generation equipment. Includes reference, tables, figures.