![]() The modified PCCP met all project requirements, including cost, delivery, constructability, pressure- and ozone-resistance. The design uses a heavy wall embedded cylinder pipe (ECP), stainless steel end rings, and full-circumferential field welds to join adjacent lengths. During the design-build process, a leading manufacturer of PCCP proposed a special design with ozone resistant materials for all wetted surfaces. Standard PCCP has several deficiencies in terms of ozone resistance. Several pipe materials were evaluated, including 316L stainless steel (SS), polyvinylidene fluoride (PVDF)-lined fiberglass-reinforced plastic (FRP), and PCCP. Due to the pressures at the Cheney Ozone Facility, conventional tanks were not feasible pipe provided the most efficient structure. ![]() Conventional ozone contactors are typically baffled concrete or stainless steel tanks with a free water surface and maximum pressures of 4 to 13 psi (0.3 – 0.9) from the depth of the contained water. Ozone is a strong oxidant, and few materials can resist degradation or destruction over a twenty-year design life of the structure. ![]() Ozone treatment of drinking water consists of generating ozone gas on-site from oxygen, dissolving the gas into water, and providing a contact time for the chemical reactions to occur. The ozone facility, procured as a design-build project and completed in June 2005, is located on the discharge side of the raw water pump station, where pressures range from 56 to 95 psi (4.0 – 6.5 bar) depending on the pumping rate. Water from the Cheney Reservoir is pumped uphill for about 7 mi (11 km), then flows another 18 mi (29 km) by gravity to the City's water treatment plant through a 60-inch (1,500 mm) diameter PCCP pipeline constructed in the early 1960's. The ozone facility, part of the City's drinking water treatment process, treats up to 80 mgd (12,600 m 3/h) raw water from the Cheney Reservoir with a maximum dissolved ozone dose of 5 mg/L to eliminate taste and odor caused by algae. The ozone contactor for the high pressure Cheney Ozone Facility, owned and operated by the City of Wichita, Kansas (City), was constructed with prestressed concrete cylinder pipe (PCCP) modified for ozone resistance.
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