Maximum available control technology

The USEPA is responsible for creating and enforcing the NESHAPs for all hazardous air pollutant sources. The CAA states that new or existing major sources must have emission standards based on the maximum available control technology (M ACT) to reduce hazardous air pollutant emissions. The MACT standards are based on the performance of the best 12% of the control devices in the same source category. These MACT emissions requirements were extended in 1997 to cover wastewater biosolid incinerators at publicly owned treatment works (POTWs) that have the potential to discharge cadmium, lead, and mercury (Richman, 1997). 

The CAA also mandated EPA to set the U.S. National Emission Standards for Hazardous Air Pollutants (NESHAP). These standards regulate air emissions of 189 listed hazardous air pollutants. The standards were set based on the best 12% of controlled facilities in each industry. A similarly high technical standard was set by EPA in the Maximum Available Control Technology rules (MACT) that have been applied to emissions of volatile organics (1995) and sulfur and other inorganic compounds (2002) from oil refineries. 

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U.S. EPA, NESHAPS—Maximum Achievable Control Technology (MACT) Standards, U.S. Environmental Protection Agency, October 2008. Available at http //www.epa.gov/combustion. 

It should be noted that the 1990 Clean Air Act Amendments (CAAA) have impacted on the control approach in a significant manner. In particular, the CAAA have placed an increased emphasis on control technology by requiring Best Available Control Technology (BACT) on new major sources and modifications, and by requiring Maximum Achievable Control Technology (MACT) on new and eodsting major sources of Hazardous Air Pollutants (HAPs). 

Particulate control is by means of either a wet scrubber or a wet electrostatic precipitator located after the condensing heat exchanger. The choice of particulate control equipment depends on the degree of control required. The particulate slurry collected by the scrubber or precipitator is circulated through a pug mill that de-waters and pelletizes the ash. The ash pellets are spread on the tree fields as a fertilizer. The ash content of the wood is less than 1% so that a maximum of 5 t/day are collected and pelletized. The particulate emission standard to be met for new wood fired power plants in the State of Wisconsin, for exan le, is based on best available control technology (BACT) and can be expected to be about 21 g/ 10 kj. 

Primary RCRA regulations call for a DRE of at least 99.99% of all POHCs. The regulations also require 99% removal of HCl from the incinerator flue gas or a maximum of 41b/h (1.8kg/h). Federal regulations require a maximum particulate emission of 0.08 gr/dscf corrected to 7% oxygen in the flue gas. In addition, many states require BACT (best available control technology). Metals emissions are dealt with in the next problem. 

In February 2012, the USEPA issued a final rule to update emissions limits for air toxics from PVC production, requiring reduced emissions of harmful toxic air emissions. This rule sets maximum achievable control technology standards for major sources and generally available control technology. 

Effluent reduction using best practicable control technology currently available (BPT) 1-day maximum (CN, A) 30-day average (CN, A) 0.00040 kg/kkg 0.00020 kg/kkg ... 

Infrequent measurements of water quality result in large statistical errors in estimation of performance versns WQS. When the available evidence indicates achieving WQS standards unlikely or impossible via application of source control technologies, the EPA imposes total maximum daily load (TDML) levels of individual pollutant discharge from point sources. 

As with the CAA, the CWA establishes performance standards (the maximum effluent concentrations allowable) and control technology guidelines applicable to various industries and sectors. These guidelines reflect data compiled from numerous industry sources, and define expected discharge levels as a function of best available technology economically achievable (BAT or BATEA). More information on effluent streams is at http //www.epa.gov/waterscience/guide/. 

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