That experience has led to the company installing another four Sulzer HSTs during its most recent facility upgrade.
Maintenance savings were a primary decision driver for UK water utility Severn Trent when it installed four Sulzer HST units in its Rushmoor wastewater treatment plant in 2012. The Rushmoor facility in Shropshire serves more than 50,000 people in the nearby town of Telford, and the HST turbocompressors were installed as part of a new aeration system built to meet the needs of the fast-growing local population.
Andy Bradford, site manager for the Rushmoor facility, comments: “The four positive displacement compressors used in the plant’s previous aeration process had each incurred around £10,000 in annual maintenance costs. Worse, the units had been prone to failures in service requiring disruptive emergency repairs. In the eight years since the switch to Sulzer HSTs, our compressor maintenance costs have been almost entirely eliminated, and the units are still operating as effectively today as when they were first installed.”
Severn Trent embarked on a further expansion project at Rushmoor in 2018, and following an extensive tendering process, Sulzer HSTs were again selected due to the lowest overall TOTEX costs and trouble-free operation of other Sulzer turbocompressors on site.
Aeration systems play a crucial role in modern wastewater treatment processes. They are also a significant driver of overall operational costs. In a typical wastewater treatment facility, for example, aeration equipment accounts for between 45% and 70% of a site’s total energy consumption, and up to 15% of its overall operating costs.
As water utilities seek to reduce costs and improve the environmental sustainability of their operations, there is growing interest in alternatives to the bulky, complex and energy-hungry blower designs that are commonly used in aeration applications.
One option is the Sulzer HST high speed turbocompressor range. According to Sulzer, these units offer a radically simpler mechanical design, with compression provided by an efficient turbo air-end, which rotates at very high speed on friction-free magnetic-levitation bearings. Energy use analyses completed in real-world wastewater treatment facilities have shown that HST-powered aeration systems typically consume 30% less energy than conventional positive-displacement blower designs.
While some users make the case for a switch to high-speed turbocompressor technology on energy consumption alone, many find that other benefits of the HST design contribute quite significantly to the overall savings. The integrated design and small footprint, for example, simplifies design installation and commissioning. The low weight of the units and the almost complete absence of mechanical vibration means they do not require specially prepared foundations, or a crane for installation.
Sulzer has developed a way to mount the HST in a container that can be easily transported to site and quickly connected to the existing pipework, power and control systems.