Using electrocoagulation (EC) to treat waste water isn’t a new process, but thanks to the patented technology available exclusively through United Rentals, it’s a lot easier for companies to take advantage of its benefits.

Electrocoagulation removes heavy metals and other contaminants from water using two charged metal plates (electrodes) that introduce metal oxide into the water. The metal oxide bonds with the contaminants in a chemical reaction, creating solid byproducts that can be removed from the water with settling and clarifying equipment.

EC offers many advantages over chemical coagulation treatments. It produces less solid waste, and unlike in chemical processes, that waste usually is not hazardous. EC doesn’t require the use of expensive chemicals; the only consumables are the two metal plates and power.

EC systems can be adjusted to remove many different types of contaminants. The primary adjustment is changing the voltage density (the amount of current flowing through the metal plates divided by the area it’s flowing through). The type of metals used for the plates — usually iron ore, aluminum or stainless steel — can be changed to remove different heavy metals. Even the speed and volume of the water moving through the system can affect the types of contaminants EC removes.

While EC generally works well, there have been some problems with traditional systems. Over time, scale builds up on the electrodes and makes them less effective. In addition, the systems have not been easy to adjust, so operators may find it difficult to handle a variety of contaminants with a single system.

Better solution, smaller footprint

After several years of research, BakerCorp, now part of United Rentals, developed a greatly improved EC system. “We have 10 patents on this technology, which prevents many of the problems traditionally found in electrocoagulation,” said Mehrzad Emanuel, who now serves as director of filtration–fluid solutions at United Rentals. “For example, we have a technology that continually prevents scaling and build-up,” he said.

The development team designed this EC system to be easy to adjust with electronics and automated controls. It’s capable of handling the tough demands of the oil and gas industry’s fracking activities — which involve hundreds of different contaminants and constantly changing conditions — as well as simpler scenarios in which is the environment is more stable and/or there are fewer contaminants to be removed.

With the EC-250 Mobile Treat Trailer, United Rentals has loaded state-of-the art electrocoagulation equipment into a compact package that can be transported to wherever it’s needed. The trailer includes three electrocoagulation modules that can be set to handle different contaminants as well as electronic controls that can run any additional pumps and clarifiers required for a wastewater treatment project.

United Rentals also offers a similar compact CL-250 Mobile Clarifier, which can remove the byproducts of the EC process from treated water before it is released back into the water supply. The CL-250 features a slant-plate design that enables it to provide the same treatment capacity as a 42-foot fixed installation clarifier.

Tackling the tough jobs

The EC-250 Mobile Treatment Trailer has been successfully used at many water treatment sites around the country, according to Emanuel. One of the most challenging projects was the cleanup of an EPA Superfund site on the Duwamish River in Seattle.

The project required the treatment of more than 63 million gallons of water. The EC-250 succeeded where other chemical cleanup systems failed. Although the Duwamish River contaminants and their volume varied during the project, the team of onsite personnel was able to adjust the process to the circumstances while maintaining a steady pace of processing.

In 2018, Frost & Sullivan, a consulting firm that annually recognizes breakthrough technologies, awarded the EC-250 and the CL-250 its new product innovation award. The company called the systems “cutting-edge, innovative treatment solutions that pair with quick and efficient service and expertise to treat water in industrial and municipal settings.” 

For select projects, United Rentals offers the EC-250 and CL-250 treatment systems at a fixed job price and provides a performance guarantee. For more information, contact United Rentals’ filtration–fluid solutions group.

Freelance writer Mary Lou Jay writes about business and technical developments in a variety of industries. She has been covering residential and commercial construction for more than 25 years.