Challenge

In March 2003, Siemens Water Technologies, formerly USFilter, was awarded a contract to provide design, installation, training, and off site recovery for a chromium contaminated groundwater supply in Texas. The site is the location for a number of chrome plating shops that have since gone out of business. The project is now part of an EPA superfund cleanup.

Solution

In order to treat up to 550 gallons per minute, a total of ten 48” diameter service vessels, each containing 60 cubic feet of resin, were installed in a lead / lag configuration. This allows the operator to monitor chromium break through for the primary tanks while maintaining an acceptable chromium discharge level for the second set of tanks.

When tests indicate the primary tanks are approaching exhaustion, our Dallas, TX branch dispatches service technicians to replace the spent resin. A resin sluicing diaphragm pump and resin storage / transfer totes are used for removal of the spent resin. Sluice water is obtained from the treated water holding tank, therefore, no additional water is required. Siemens Water Technologies brings fresh resin and reloads the service tanks. The tank manifolds are configured in such a way as to allow what was the lag bank to become
the lead without moving the vessels. This improves the efficiency of the resin exchange and insures that maximum resin life can be obtained. Siemens service technicians visually inspect the vessel internals, install the fresh resin, and return the system to service.

Spent resins are transported to Siemens' Roseville, Minnesota regeneration facility, a RCRA permitted site, for recovery.

Results

Original designs called for on-site regeneration of the ion exchange resin. The successful contractor was to be responsible for operating the system and disposing of all regenerant waste. Siemens' design eliminated all equipment needed for regeneration on site, saving
capital and space.

Siemens’ service contract provides this customer with a low capital investment, low operating cost option where no wastes are generated on site. Removal of the spent and contaminated resins from the site eliminates concerns of recontamination.