Union Bridge plant manager Kent Martin said company officials have been in talks with the Maryland Department of the Environment for the past year, since an environmental group released a report citing the Union Bridge facility as one of the highest mercury releasers in the state.
The US Environmental Protection Agency and MDE did not have standards for mercury releases from cement plants, but the EPA has been in the process of developing a limit over the past few years. The EPA is expected to release the new limits in March.
Martin said Lehigh is going to experiment with injecting activated carbon into the ductwork leading up to the baghouse that filters particulate matter, to keep it from being released into the air. The carbon binds to the mercury, Martin said, allowing it to be trapped by the baghouse filters.
A similar process is used at power plants, Martin said, but he believes this will be the first time it has been tried at a cement plant, at least on the East Coast.
The equipment is being set up and monitored by an outside contractor, Martin said. During the test period, which will last several weeks, hundreds of samples will be taken at different stages, Martin said, and these will be analyzed over the next few months. The tests will help determine how to make the carbon injection system most effective, Martin said, as well as test what effect the process has on the cement product.
“Carbon itself is not good for cement,” Martin said.
Martin said the company plans to have the analysis report finished by early 2010. The goal is to then have the equipment permanently in place by March 2012 — a year before the EPA standards for mercury released at cement plants go into effect, he said.