Challenge

Environmental discharge limits for copper continue to decrease for industrial facilities across the United States. Although humans can tolerate higher levels, even low level copper exposure is toxic to algae and small marine life in the environment.

In August 2010, a hydrocarbon processing facility located in Texas was faced with a goal to reduce copper and zinc below 10ppb in the discharge from the facility. Siemens was contacted to evaluate newly developed adsorptive media that specifically remove trace levels of copper and zinc. Column studies of water sampled from the site were tested at Siemens' Roseville, MN facility and the comapany's new adsorptive media was selected as the best technology to achieve the treatment goal. 

Solution

A full scale pilot system was installed at the facility to achieve the treatment goals from the cooling loop blowdown.  The Siemens’ solution included wastewater ion exchange (WWIX) service to remove the contamination and comply with discharge standards. Wastewater ion exchange is a service-based option which utilizes the adsorptive media in temporary, rental vessels to remove the specific contaminant. DOT approved vessels containing the media treat the water until the capacity is reached. Once exhausted, the WWIX vessels are removed and replaced with fresh, DOT-compliant vessels and returned to service. Exhausted vessels are returned to our processing facility where the contaminants are removed from the media.

After installation the customer experienced inconsistent results and required additional assistance to eliminate cross contamination from the site.  It was determined that the certified laboratory sample containers used for testing purposes included an acid, or preservative, for the sample. Under these low level conditions only the most pure grades of acid can be used otherwise they contribute to the reportable metals in the effluent.  After improvements, data from the certified independent lab show consistent results below 2ppb in the discharge.

Results

After improvements, data from the certified independent lab show consistent results below 2ppb in the discharge.

Siemens' new adsorptive media removes trace levels of metals such as copper, zinc, mercury, cadmium and others from complex wastewater that is not possible with standard ion exchange resin technologies. This  new product is a potential application to all customers facing lower discharge limits to the environment.

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