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Tabbed activity describing the three tiers of BACT

Tab Title: Tier I

Tab Content:

· Tier I BACT requires emission reduction levels that have been approved for permits recently issued for the same process and/or industry.

· The permit review should only move on to Tier II if BACT cannot be determined in Tier I.

Tab Title: Tier II

Tab Content:

· Tier II BACT requires emission reduction levels that have been approved for recently issued permits for similar emission streams in a different process or industry.

· The permit review should only move on to Tier III if BACT cannot be determined in Tier II.

Tab Title: Tier III

Tab Content:

· A Tier III BACT review requires a detailed technical and quantitative economic analysis.

· A Tier III BACT review entails the following....

» All control technologies are identified.

» The technologies that are not technically feasible are eliminated and the remaining ones are ranked by emissions reduced.

» Case-by-case consideration is given to energy, environmental, and economic impacts to determine cost-effectiveness (i.e., dollars per ton of pollutant reduced).

» The most effective option selected, based on cost-effectiveness and performance, is BACT.

· A Tier III evaluation is rarely necessary because technical practicability and economic reasonableness have usually been firmly established by industry practice as identified in the first two tiers.

· Tiers I and II must be evaluated before moving to Tier III. Tier III cannot be the only component of a BACT evaluation.


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