Scrubbing brick kiln emissions to meet regulations. (compliance methods of brick plants to EPA's Clean Air Act Amendments of 1990)

A hydrated lime scrubbing technology has performed successfully at several brick plants.

Early in 1998, the Environmental Protection Agency (EPA) sent out an extensive questionnaire to every structural clay plant in the U.S. Some plant operators may have already experienced first-hand state regulations that require the installation of scrubbing equipment to clean kiln exhaust gases. But for many plant operators, this questionnaire may have been the first indication of the EPA's interest in their kiln stack emissions.

The EPA is required by the Clean Air Act Amendments (CAAA) of 1990 to establish national regulations to control 188 "hazardous air pollutants," known as HAPs. Among the 188 HAPs is hydrogen fluoride (HF), an acid gas commonly emitted when clays and shales are fired. The CAAA require the installation of Maximum Achievable Control Technology (MACT) emission control equipment on processes that emit more than 10 tons per year of any one HAP or more than 25 tons per year of all combined HAPs.

The CAAA further stipulate strict guidelines for establishing MACT regulations. These regulations must be based on the best performing existing emission control systems in an industry. Therefore, the EPA is required to conduct a survey in each industry affected by the CAAA regulations, leading to the questionnaires sent out earlier this year. In the coming months, the EPA will tabulate the survey results …