The challenge

The wastewater treatment plant was designed around using two larger centrifugal blowers, with the HST 2500 as trim and back-up, to meet the capacity of 4.4 MGD (16.6 MLD), utilizing the activated sludge process with fine bubble diffused air. The plant typically treats 1.2-1.5 MGD (4.5-5.7 MLD) with a maximum of 3 MGD (11.3 MLD). With this reduced influent, the city considered that the two larger centrifugal blowers were too big for the process demands and decided to utilize the Sulzer HST 2500 for continuous use. The Sulzer HST 2500 typically operates in the 45% to 85% performance range for 24 hours a day and 7 days a week. A reliable and dependable solution was needed.

The solution

In September 2016, the Victoria WWTP went online and shortly afterward the Sulzer HST 2500 became the primary blower for the plant. However, on August 25th, 2017 the Sulzer HST was put to a test that nobody could predict. Hurricane Harvey hit the area as a category 4 storm and the Sulzer HST was exposed to the full force of the storm for 24-36 hours. During the hurricane, the plant operators stayed in a nearby building for five days, riding out the storm. They expected the worst outcome for the HST turbocompressor, but once a Sulzer service technician arrived at the site, he had excellent news. The only part that was damaged was the keypad and HMI on the front of the unit, which was quickly replaced and moved inside the enclosed building.