Challenge

Whole Effluent Toxicity (WET) testing of wastewater is a common method to characterize and measure the aggregate toxicity of wastewater that is discharged into streams, lakes and rivers.

In the Fall 2005, contractors for a northern Kentucky Municipal Water & Sewer Service contacted Siemens Water Technologies for assistance to comply with WET testing goals for the facility. The municipality receives a majority of its wastewater from a local automotive manufacturer that contains trace levels of heavy metals such as copper, nickel and many other organic contaminants.

Although no specific contaminant violated the discharge standard, the facility did not consistently achieve required results under WET testing necessary under permits from the Kentucky EPA.  The inability to pass these tests on a regular basis caused the municipality to seek a permanent treatment solution to provide reliable and consistent treatment results.

Solution

Siemens’ solution included the coupling of carbon adsorption with custom formulated ion exchange treatment technology to remove trace residual contaminants in the facility effluent. Bench scale pilot testing was performed in October 2005 and then a pilot treatment system installed to evaluate the technology.

The permanent system featured HP® Series carbon adsorbers in a lead/lag configuration followed by an HP® Series vessel containing ion exchange resin. The combination of carbon for the removal of trace organic contaminants with custom formulated ion exchange media was chosen to selectively remove trace inorganic metals from the wastewater.

Results

Siemens’ solution was selected after successful pilot testing and the system was installed in April, 2006.

Since implementing the new treatment technology, the customer has remained in compliance with WET testing goals as required by the Kentucky EPA.

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