A new specialty media that removes regulated metals from industrial wastewater, groundwater and storm runoff water has been introduced by Siemens. The SCU™ Trace Metal Removal Media removes trace levels of metals such as copper, zinc, lead, mercury, cadmium, trivalent chromium, nickel and others from complex wastewater to levels not possible with ion exchange resins.
Historically, ion exchange resins have the ability to reduce heavy metals to 25 parts per billion (ppb) in typical industrial applications, depending on the contaminant and chemistry of the wastewater. With many industries facing more stringent discharge levels, Siemens developed the SCU™ specialty media to help industries and municipalities meet these new levels. Now available in North America, the media achieves levels below one ppb for most metals at flow rates up to 5,000 gallons per minute. For mercury, the media can achieve levels below 12 parts per trillion (ppt), which meet the current U.S. targets for discharge into the environment.
“Siemens SCU™ Trace Metal Removal Media is truly a unique product for demanding treatment applications and low discharge limits that typical ion exchange resin and chemical additives cannot achieve,” said Adam Szczesniak, product manager, Water Technologies Services, Siemens Industry Inc.
Depending on customers’ needs, the company offers both short-term emergency and long-term permanent SCU™ media systems. The media is replaceable and exhausted media is transferred by Siemens’ service technicians to the company’s RCRA-certified central treatment and processing facility. Both non-hazardous and hazardous wastes are then treated in compliance with all state and federal guidelines, and valuable metals are recycled into secondary raw materials when possible.
Other benefits of the specialty media include a small footprint and minimal space requirements, a service-based solution that reduces capital investment as well as a monthly rental option. Additionally, Siemens’ full-service applications lab can perform bench-scale testing to confirm the performance of systems before installation.
The company’s service exchange provides the flexibility to add or remove treatment capacity as the customer’s business grows or compliance limits change. In this case, systems are simply modified to adjust the size or media type to adapt to the process needs. This option also saves manufacturing space while minimizing maintenance and installation requirements.
In August 2010, an electroplating facility in California specializing in aircraft components was issued specialty permit levels for the reduction of cadmium in discharge wastewater. The current permit of 250 ppb was reduced to 70 ppb and the allowed cadmium levels are expected to move lower over the next few years.
Siemens was contacted to evaluate potential treatment alternatives and evaluated both ion exchange and specially developed adsorptive media that specifically targets regulated metals such as cadmium in complex wastewaters.
Column studies of water sampled from the site were tested at Siemens’ Roseville, MN, facility and the specialty media was selected as the best technology to achieve the treatment goal. The media’s performance reduced cadmium in the lab sample from over 400 ppb to less then 1 ppb.
A full scale pilot system was installed at the facility to achieve the treatment goals from the plating process. The specialty media effectively reduced the wastewater cadmium level to below the desired permit levels without the need for additional pH adjustment, thereby saving the customer the cost for additional chemical preparation and also, eliminated concerns associated with chlorine damage to the media.