Meeting new air standards with a volatile organic treatment train

摘要

The U.S. Environmental Protection Agency (EPA) issued the second phase of the organic air emission standards for hazardous waste treatment, storage, and disposal facilities (TSDFs) and hazardous waste generators in December 1994. These standards (referred to as the Subpart CC standards) are designed to further reduce organic air emissions from hazardous waste management activities. To comply with these new air standards, Lawrence Livermore National Laboratory (LLNL) is designing a volatile organic removal and destruction treatment train to modify its existing Waste Water Treatment Tank Farm (hereafter called Tank Farm). LLNL's Tank Farm consists of six, 7,000-L open-top tanks used to store and treat aqueous low-level radioactive, mixed, and hazardous waste before discharging it to the local publicly owned treatment works. The waste stored and treated in the tanks have elevated volatile organic constituent (VOC) concentrations. According to the Subpart CC standards, tanks handling waste with similar VOC concentrations must be retrofitted with a cover and an emission control device for cover openings that achieves at least a 95% reduction in the total organic content of the vented gas stream. However, LLNL concluded that the removal and destruction of VOCs from waste before they enter the Tank Farm would demonstrate compliance with the Subpart CC standards more effectively and be more cost effective than installation of air emission control devices on the Tank Farm. LLNL has designed this removal and destruction technique to consist of an air stripper, high-efficiency particulate air (HEPA) filter, catalytic oxidizer, scrubber, and mist eliminator.