TREATMENT ALTERNATIVES FOR MON WASTEWATER COMPLIANCE: WHEN WILL BIOLOGICAL TREATMENT BE THE ANSWER?

The U.S. Environmental Protection Agency (EPA) promulgated the National Emissions Standards for the Miscellaneous Organic Chemical Manufacturing (MON) on November 10, 2003 (40 CFR 63, Subpart FFFF). This regulation requires that major sources in the MON category control emissions of hazardous air pollutants (HAP) to achieve the standards that EPA has prescribed for the emissions sources based on maximum available control technology (MACT).The MON regulation requires chemical plants that are major sources of HAP emissions to identify wastewater streams that require management to control HAP emissions. The MON directs a regulated plant to the Synthetic Organic Manufacturing Industry Hazardous Organic NESHAP rule (HON)(40 CFR 63, Subpart G) for the control requirements that are to be achieved for wastewater streams that are subject to regulation.The HON regulation identifies biological treatment as one of the control options for HAPs in wastewater. Other existing MACT rules, including the pharmaceutical manufacturing MACT and the pesticide manufacturing MACT, also allow the use of biological treatment to control HAPs in wastewater streams. Because these MACT regulations are already effective, there is a historical database on the methods used by major sources in these categories to comply with their wastewater standards. This historical database can be used to identify the wastewater and treatment unit characteristics that make biological treatment a cost-effective MACT compliance technology. This paper describes successful applications of biological treatment to comply with MACT wastewater provisions and summarizes the principal characteristics of the wastewaters and treatment units that are used for compliance.