Challenge

After experiencing filter problems in their wastewater effluent polishing, the Sanitary Board of Bluefield, West Virginia decided it was time to upgrade their existing two pump traveling bridge filters.  Unfortunately, financial constraints were limiting the possibility of any completely new equipment.

Solution

After evaluating all the potential suppliers, the Sanitary Board decided to replace all three of their two pump traveling bridge filters with a retrofitted system- incorporating the Gravisand technology from Siemens Water Technologies.  Each of their three filters had a capacity of 2 million gallons per day.

The Gravisand® Filtration System incorporates:

• A proprietary No-Wear™ backwash shoe that eliminates the need for a wear strip liner and associated maintenance.
• A patented tubular underdrain that is non-segmented, and is not subject to irreversible biological fouling.
• A unique indexing system that isolates each filter cell that eliminates costly media migration.

Results

According to Mr. Allan Haga, engineer for the contractor Hammond-Mitchell, “This system far exceeds others I have installed”.

Since the Gravisand filtration system has been installed at the Bluefield plant, operators have experienced:

• A much simpler system that is easier to operate.
• Flawless filter performance, consistently achieving the desired effluent quality.
• A decrease in maintenance costs, such as replacement parts and the time it takes to install them.