Asphalt Concrete Plants

TNRCC Rule 116.111(3) in Regulation VI requires that Best
Available Control Technology (BACT) be applied to all
facilities that must obtain a permit.  BACT is defined as any
control method which is technically feasible and economically
reasonable.  BACT determinations are made on a case-by-case
basis.  The applicant is encourage to talk with a TNRCC NSR
Permit Engineer to determine BACT for the facility. 
Current control practices include:  

1.  Fabric filter baghouses or venturi scrubbers with at least
    ninety-eight percent efficiency to control particulate
    matter from the drum/dryer/mixer.  
2.  All aggregate materials washed prior to delivery.  
3.  At least seventy percent control of fugitive dust emission
    from the handling of aggregate materials.  
4.  At least ninety-five percent control of fugitive dust
    emissions from all roads and traffic areas.  
5.  Less than five percent opacity from all point sources.
6.  Maximum mix temperature of 325 F.
7.  At least ninety-nine percent control of all volatile
    organic compound (VOC) emissions resulting from cutback or
    emulsified liquid asphalt.  
8.  A mechanism to eliminate hot gas scorching when using
    recycled asphalt products.  
9.  Sweet natural gas as a fuel source for the operation of
    the dryer.  
10. A maximum of 0.3 percent total sulfur in any liquid fuel
    used.  
11. Additional controls may be required if significant VOC
    concentrations are detected from the use of crumb rubber
    or any other additive.  

The control requirements listed are guidelines to help the
applicant determine what the TNRCC is currently considering as
BACT; however these control levels are subject to change.