News | October 25, 2011

Siemens Replaces Clarifiers In Denver's Metro Wastewater Reclamation District Plant

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District chooses Siemens for second time as clarifier retrofit equipment provider

Siemens Industry Automation Division is replacing secondary clarification treatment at the Metro Wastewater Reclamation District's Robert W. Hite Treatment Facility in Denver, Colorado, USA, with ten Tow-Bro high-performance clarifiers. Improvements to the main treatment facility are needed to replace aging clarification equipment and improve overall treatment performance. Part of a two-phase plant expansion project, the systems are valued at more than US$3.5M. The clarifiers are expected to be shipped in 2012, with five projected to come online in 2013 and the other five, in 2014.

The ten 140-ft diameter Tow-Bro high-performance clarifiers from Siemens Water Technologies, a business unit of Siemens Industry Automation Division, will be retrofit into existing concrete basins for rapid settled secondary sludge removal from the clarifier, with maximum solids concentration and minimum sludge agitation. The Tow-Bro clarifier will remove settled solids uniformly under a wider variety of flow, solids loading, and sludge settling conditions. The clarifier's simple Unitube header design allows for flexible operation and easy maintenance.

Siemens first worked with the Metro District in Denver in 2008, when the company provided the district with twelve 130-ft Tow-Bro clarifiers worth approximately US$5M for its North Secondary Improvements Project. The district selected the equipment provider for the latest plant upgrade because of Siemens' experience and performance, service facilities and availability of qualified service personnel. Parts inventoried and quality assurance and warranty were also important considerations.

The Tow-Bro clarifier design uses a center-feed configuration with peripheral effluent launders. Flow enters the clarifier through a specially designed maze-type energy dissipating inlet that ensures optimal velocity and circulation of flow throughout the whole clarifier. After initial energy dissipation, solids are flocculated and settle to the tank floor where they are removed uniformly by the Tow-Bro Unitube Header. Concentrated settled sludge is returned to the aeration basin from the clarifier. Clarified effluent flows into an inboard launder and exits the tank. Scum is removed via a ducking skimmer assembly. The treated water then flows to the Metro District's disinfection facilities for further treatment prior to discharge into the South Platte River.

The Metro District is the largest wastewater treatment facility in the Rocky Mountain West. The service area includes a population of nearly 1.7 million people and encompasses approximately 715 square miles, together with about 40 water and sanitation districts in the metropolitan Denver area. The Robert W. Hite Treatment Facility treats about 140 million gallons (530 mega liters) of wastewater each day which makes up 85 percent of the South Platte River once it is discharged.

To learn more about Tow-Bro high-performance clarifiers, please stop by WEFTEC.11 Booth # 1549 or visit

For more information, visit

About Siemens Industry Sector
The Siemens Industry Sector (Erlangen, Germany) is the world's leading supplier of innovative and environmentally friendly products and solutions for industrial customers. With end-to-end automation technology and industrial software, solid vertical-market expertise, and technology-based services, the Sector enhances its customers' productivity, efficiency, and flexibility. With a global workforce of more than 100,000 employees, the Industry Sector comprises the Divisions Industry Automation, Drive Technologies and Customer Services as well as the Business Unit Metals Technologies. For more information, visit

About Siemens Industry Automation Division
The Siemens Industry Automation Division (Nuremberg, Germany) supports the entire value chain of its industrial customers – from product design to production and services – with an unmatched combination of automation technology, industrial control technology, and industrial software. With its software solutions, the Division can shorten the time-to-market of new products by up to 50 percent. Industry Automation comprises five Business Units: Industrial Automation Systems, Control Components and Systems Engineering, Sensors and Communications, Siemens PLM Software, and Water Technologies. For more information, visit

SOURCE: Evoqua Water Technologies