How do lead acid batteries affect the environment?
Lead in the body is measured by the amount of lead in the blood and sometimes in the bone. According to the Centre for Disease Control and Prevention (DCD) the level of concern is for children whose blood leads measures 10 micrograms of lead per deciliter of whole blood. Parents should look at the child¡¯s environment to see if there are any sources of lead, such as old leaded paint. If a child has a level of 15 micrograms of lead per deciliter of blood, parents should look at the child¡¯s home, school and play environments and their own jobs, hobbies or other situations that could expose the child to lead.
The Occupational Safety and Health Administration (OSHA) threshold for adult workers in battery plants is 50 micrograms of lead per deciliter of whole blood. A worker who tests at a 50 will be moved to a different job in the facility until his or her blood lead level falls. The employee will be counselled and monitored to keep the blood level below the OSHA threshold.
Through a voluntary agreement made with OSHA in 1996, Battery Council members have been working to reduce the 50 microgram medical removal threshold to 40 micrograms within the next five years. Blood testing is an important tool for people who are regularly exposed to lead.
Battery manufacturers and recyclers have education programs and health maintenance programs for their employees, backed up by regular blood lead testing efforts. Regular monitoring of blood lead levels allows a physician to track the success of lead reduction programs. Test results are a critical tool in the employees¡¯ health management programs.
How is environmental pollution controlled at our battery plant?
AIR FILTERS AND SCRUBBERS
To keep microscopic particles of airborne lead emissions to a minimum, manufacturers and recyclers use high efficiency air filters and wet scrubbers to filter plant air before it is released to the atmosphere. The filters re inspected and replaced regularly. The filters also are equipped with alarms, and the process is shut down or re-routed should a filter tear or break.
VRLA battery Manufacturers and recyclers capture and treat process water to keep lead out of streams and rivers. The water is tested before it is released to be certain it meets clean water standards.
At recycling plants, air monitors are installed at the perimeter of each property to make sure any lead in the air is below the allowable limit. The limit is 1.5 micrograms of lead per cubic meter of air, averaged on a quarterly basis.
Children can be exposed to lead when a parent who works at a lead plant carries dust home on shoes or work clothes, or in the worker¡¯s hair. OSHA regulations require workers in high lead exposure areas of the plant to leave work clothes and shoes at the plant and to shower and wash their hair before going home. They also require workers in high lead areas of the plant to wear a respirator, a device filters lead particles out of the air a worker breathes. Education programs train workers to wash thoroughly before eating or smoking during lunch or breaks and to practice other habits that safeguard their health.
Plants have a regular program of exterior vacuuming or washing down paved areas and capturing and treating rainwater runoff. Vehicles that transport lead products typically are hosed down before leaving a facility so that any dust on tyres or the vehicle body is not carried to public roads.
When taken together, all of these practices add up to a very responsible effort on the part of lead acid battery manufacturers and recyclers to keep even small amounts of lead out of the environment. It¡¯s the industrial equivalent of a homeowner who wants to cut down on utility bills by adding extra insulation in the attic, caulking every window, weather stripping every door and putting an insulation blanket on the hot water heater. Together, the efforts make a measurable difference.
Lead acid batteries are the environmental success story of our time. Roughly 93 percent of all battery lead is recycled. Compared to 42% of newspapers, 55%of aluminium soft drink and beer cans, and 40% of plastic soft drink bottles, lead acid batteries top the list of the most highly recycled consumer products.
The lead grids, lead oxide and other lead parts are cleaned and then melted together in smelting furnaces.
The molten lead is poured into ingot moulds. Large ingots weighing about 2 000 pounds are called hogs. Smaller ingots weighing 65 pounds are called pigs. After a few minutes the impurities otherwise known as dross, float to the top of the still molten lead in the ingot moulds. The dross is scraped away and the ingots are left to cool.
When the ingots are cool, they are removed from the moulds and sent to battery manufacturers, where they are re melted and used in the production of new lead plates and other parts for new batteries.