In the world of air pollution control engineering, the requirement to perform a Best Available Control Technology Analysis (BACT Analysis) is nearly unavoidable. Regulatory requirements associated with the BACT analysis process vary from state to state but the following generally applies:

  • Identify all available control systems that have the PRACTICAL POTENTIAL for application to the unit
  • Eliminate TECHNICALLY INFEASIBLE systems
  • Consider Energy, Economic, and Environmental Impacts
  • Reject systems based on the above considerations

Those systems which are considered technically feasible are ranked from those providing the most control to those providing the least control. The emission rate utilizing the most efficient control system is considered the Lowest Achievable Emission Rate (LAER). For example, for the control of nitrogen oxides from a boiler a Selective Catalytic Reduction (SCR) system may provide the highest control efficiency while a Selective Non-Catalytic Reduction (SNCR) system may provide the least. In this case, the SCR would be ranked first and the emission rate associated with the use of the SCR would be the LAER.

In some cases, the control device providing LAER isn’t a feasible solution for pollution reduction from the emission unit. In general, energy, economic, and environmental impacts must be considered when determining a systems feasibility. Control scenarios are eliminated based on these impacts and the most efficient remaining system is the Best Available Control Technology or BACT.