Updated equipment aids in the management of wastewater for lead-acid battery recycling.
By David C. Richardson
Ever wonder what happens to all those car batteries you trade in at the auto parts dealer? One of the most successful recycling programs in any industry is the program that encompasses automobile battery recycling. Lead-acid batteries are the ultimate reusables. During normal use they recharge innumerable times, and even after their useful life for energy storage is over, they can return to the seller for recycling. But then what happens?
According to a statement released by the company in commemoration of Earth Day 2001, Exide Technologies Inc. says it recycles approximately 50 million spent lead-acid batteries per year in its 11 battery recycling facilities. “We were recycling our products many years before other industries recognized the benefits of recycling,” says Robert A. Lutz, then chairman and chief executive officer of Exide Technologies. “It wouldn’t be an exaggeration to say that the lead from a battery we built in 1950 might still be used in a new Exide battery produced today. We recycle because it makes economic sense and environmental sense.”
A History of Industry
Among its recycling facilities, Exide Technologies operates a secondary smelting plant in Vernon, CA (a highly industrialized locality near Los Angeles, CA). The plant processes 11 million used automobile batteries each year that, according to Jose Kou, chief of the Southern California Permitting and Corrective Action Branch within the California Department of Toxic Substances Control (DTSC), is roughly equivalent to the number of automobile batteries that would need to be disposed of annually throughout California alone. In addition, he says, the plant aggregates and processes lead-acid batteries formerly used in other industries, such as telecommunications.
However, the constituents of car batteries and other lead-acid batteries present certain hazards for handling during and through the recycling process. Each battery contains about 0.75 of a gallon of 37% sulfuric-acid electrolyte. The other major constituent of lead-acid batteries is, of course, lead.
According to Kou, the State of California considers batteries to be hazardous waste. In California, the Resource Conservation and Recovery Act (RCRA) regulations for managing hazardous waste are administered by the DTSC, under the California EPA. In order for Exide Technologies to continue to operate its battery processing plant and secondary smelting operation in Vernon, Kou says a Hazardous Waste Facility Permit would be required from the DTSC.
The site of the Exide Technologies plant has a history in the metals business dating back to 1922. The site has been used for various metal fabrication and reclamation activities under a number of sequential owners. More recently it was owned by GNB Batteries, which itself was acquired by Exide Technologies. In 1983, a wastewater treatment plant, equalization lagoon, and septic lagoon were constructed to treat washdown water, effluent from showers, laundry, and restrooms at the facility. Separate National Pollutant Discharge Elimination System–permitted outfalls service all of the water treatment occurring at the facility, from wastewater treatment to stormwater to process wastewater and septic lagoons.
Complete Refabrication
Spent batteries from automobiles, communications devices, and other equipment are stored at a central location on the Exide site until such time as the feedstock for the reclamation process begins. During the reclamation process, the batteries are crushed and the metallic lead is removed mechanically. The polypropylene material from the battery casings is pulverized and directed to a different production process to be formed into pellets for reuse. The sulfuric acid is drained off, and the spent battery acid is processed to extract components that are converted to sodium sulfate, a product used in textiles, detergents, and other products. The lead is fed into smelters to produce lead ingots of high purity. Exide Technologies says 97% of the lead from the original batteries is captured and reused in the manufacture of new batteries. According to company literature, “A new Exide battery contains nearly 100 percent recycled lead and plastic, and the materials can be recycled indefinitely.”
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Photo: RMT Inc. |
| Exide Technologies recycles lead from batteries dating back to the ’50s. |
The secondary smelting operation proceeded normally at the Exide plant under an interim permit from the DTSC. Over the years, as the smelting operations grew, the wastewater treatment plant was also expanded. Chuck West, senior wastewater consultant at RMT Inc., who worked as a consultant on the Vernon site through his previous firm, Lake Engineering, says the wastewater treatment plant expansion was a matter of putting together whatever it took to make it work. “It was like a junkyard mechanics TV show. The system was made out of pieces and parts,” he says. “The goal, 10 years ago, was to get the place in compliance. Some of the equipment was oversize, and some of it was undersize, but we could make it function.” Using technology that West helped pioneer, he says, “We had revamped the plant to accommodate ferrohydride chemistry back in the early ’90s,” which, he says gave the plant the capability to meet discharge standards for antimony, a process that previously proved challenging for the secondary smelter to meet.
Kou says the plant operating under an interim permit was performing as specified—until the landscape suddenly changed.
“It was around 1998,” West says, when an earthquake hit. He describes how it sent several pieces of the wastewater treatment plant “dancing across the parking lot. It was pretty sobering,” he says. “Nobody would have thought these tanks would move, filled with 50,000 gallons of water.” Though it was a minor earthquake and the damage was minimal, it pointed out the need for major improvements “to get the plant seismically up to date.” Just as important, West says, the regulatory landscape had begun to change at the same time. Water-quality regulations were becoming more stringent, and West says a number of court decisions mandated other improvements to the plant. In order to maintain an operating permit at the site and move from the interim permit status to a permanent permit, Exide Technologies would need to upgrade the plant.
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Photo: Centre City Studios |
| Exide reuses 97% of the lead recaptured from old batteries. |
Kou says, “The wastewater treatment plant had inadequate secondary containment.” In order to qualify for a new permit, Exide Technologies would be required to construct a berm as a secondary containment structure around the entire wastewater treatment plant. According to Kou, the secondary containment would need to have the volume that would hold the contents of the largest tank, or 10% of the total volume of the tanks, plus the volume of runoff generated by a 24-hour, 25-year storm.
West says constructing such a berm would be a challenge. The existing wastewater plant had sprawled over several acres, and intervening structures and equipment would pose a constraint to any attempt to define and encompass the facility’s perimeter. West says when consultants evaluated the options, it was determined that building a berm around the existing plant would not be feasible. Additionally, he says, the 24-hour nature of the smelting operation and its requirement for continuous water treatment made shuttering the existing plant for the needed renovations a nonstarter. “The decision was made to construct a new wastewater treatment plant at a new site on the property.” He said that decision would facilitate the construction of the required secondary containment structure. West says the new plant would provide essentially the same treatment as the previous plant but with operational benefits for the overall reclamation and smelting facility.
“Instead of having the plant spread out over a large area, we put in one consolidated system making operations easier to handle.” He says it was “a part of looking at wastewater treatment as part of industrial operations.”
Further, he says, to address the seismic issue, “We hired a subcontractor who was a certified seismic analyst who went through to see what had to be anchored.We needed to use more squat tanks and pump the water, rather than the ordinary engineering.”
According to Kou, a 60-millimeter (mm) high-density polyethylene geomembrane liner system was installed under the entire wastewater treatment plant. (The stormwater retention pond walls and floor areas are lined with 45-mm Hypalon overliner and 110-mm geotextile rubber and a 40-mm PVC underliner continuous over the slab.
With regard to pumps, West says, “You use a lot of plastic and fiberglass where it’s going to be exposed to low pHs. Most of the rest of it does not require extremely specialized equipment; it’s just big equipment.” According to West, there are a variety of suppliers that can provide appropriate equipment for this application. “I tend to lean toward suppliers the clients are comfortable with. If they are using a lot of Goulds pumps elsewhere in the plant, that’s what I use for the wastewater treatment.”
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Photo: RMT Inc. |
| The clarifiers are part of a 24-hour-a-day treatment cycle. |
West says, “Basically the same types of equipment were used to build the new one as were used in the old one; they were just optimized.”
The wastewater treatment plant system and secondary containment system and secondary containment projects were approved by the DTSC on June 30, 2000. The installation of the secondary containment system was completed in December 2000, and the new wastewater treatment plant system was completed in December 2001. The wastewater treatment plant system was fully operational in May 2002.
The plant has a capacity of 310,000 gallons and actually processes about 250,000 gallons of wastewater per day. Though West says the lead concentrations coming into the plant “are all over from 100 parts per million to 1,000 parts per million, the plant gets the lead down to sub-parts per billion,” before discharge to the publicly owned treatment works (POTW).
“There are probably 300 parts of solids for every million parts of water that go through the system and get captured,” West says. Being mostly lead, these solids “go back to the smelter for recovery.”
An Evolving Process
West says there is a lot of work to do in managing wastewater treatment for the secondary smelting industry. “We’re in a cycle where things may be wearing out. In addition, what’s happened mostly is regulation has changed as local POTWs have taken the responsibility for managing industrial users. They’ve pushed the limits downward.”
West says the recycling business is also undergoing constant change and development. Some companies, he says, are exploring zero emissions in secondary smelting recycling projects, and some companies are bringing the expertise in-house. “The technology can be very avant-garde, and some of the companies doing it have chosen to keep it very close.” At the same time, he says, in the new global way of doing business, a lot of the expertise has been dispersed.
Jeff Pierce, environmental engineer with RMT Inc., says the time factor is something to keep in mind when responding to regulations. “It takes awhile to go through the permit process—just like in any planning project, you have to budget the time for working with state and local government to make sure you can get your facility permitted. You have to take that aspect into account.”
A Necessary Business
From the regulatory perspective, Kou says the wastewater treatment upgrade at the Exide Technologies plant was a successful project. In the process itself, he says, very little was wasted. The old tanks and the metal parts from the old plant were drained and cleaned up before they were cut into pieces and fed into the furnaces for recycling. Kou says, “When you’re working with a big company like Exide, they have the resources to get the job done.”
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Photo: RMT Inc. |
| The plant has a capacity of 310,000 gallons. |
However, Kou says, the permit process is ongoing, and the final decision on Exide Technologies’ Hazardous Waste Facility Permit application for the site has not been announced. At this point, he explains, the application is going through the public comment process. “We have continuing involvement. We have a compliance program, and we will continue to do inspections at the facility after the permit decisions are made.”
The battery recycling operation covers a lot of ground, Kou adds. “The bulk of the site is devoted to receipt and storage, breaking and smelting of metal, and storage of the product before it gets sent to the battery manufacturers.
“It’s the type of business that’s needed in California,” he says. “They need someplace to deal with all the batteries. If the company were not there, these batteries would have ended up being dumped in landfills.”
The fate of used batteries? Now you know—another example of “whatever is old is new again.”
David C. Richardson is a writer based in Baltimore, MD.
OW - January/February 2008
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