
                                       
                                       

                                  MEMORANDUM

Tetra Tech, Inc.
10306 Eaton Place, Suite 340
Fairfax, VA 22030
phone	703-385-6000
fax	703-385-6007

TO:			Paul Shriner and Jan Matuszko, EPA
	
FROM:		Kelly Meadows, Tetra Tech

DATE: 		September 10, 2008

SUBJECT:	Phase II Facilities with Thermal Discharge Limits 

Tetra Tech was tasked with determining the number of facilities who are subject to thermal discharge limits in their NPDES permits.  While summary-level data of this type is not readily available, a query of EPA's Permit Compliance System (PCS) provides some insight to the issue.

PCS was queried for all of the Phase II facilities (by NPDES permit number) and cooling water and temperature-related fields were examined.  Data was further screened by eliminating records that appear to refer to permit conditions that are no longer contained in the facility's current permit (e.g., optional monitoring and deleted monitoring conditions fields).  The tables below shows the results of the analysis: approximately 78 facilities (of 544 or 14%) appear to have thermal discharge limits of some type.

Note that this analysis has significant limitations and likely represents an approximate number of facilities; most likely it represents the minimum number of facilities with thermal discharge conditions.  These limitations include: 

   * Several states do not submit information to PCS
   * Some states may not input data to all fields
   * PCS may not adequately display narrative limits (thermal limits often narrative, such as a limit not to exceed 1°C within a radius of 1000 meters of the discharge)

In short, a detailed review of each individual permit and fact sheet would be required to most accurately assess the presence and scope of thermal discharge permit conditions at these facilities.

Thermal Limits by Type
                                       
                             Number of facilities
                               Percent of total
Water Temperature
                                      32
                                    41.03%
Temperature Difference between Sample and Upstream
                                       4
                                     5.13%
BTUs/Heat Rejected
                                      21
                                    26.92%
Combination of the Above
                                      21
                                    26.92%
Total
                                      78
                                       

Thermal Limits by Monitoring Frequency
                                       
                             Number of facilities
                               Percent of total
Continuous
                                      17
                                    21.79%
Monthly
                                       3
                                     3.85%
Daily/Weekly
                                      37
                                    47.44%
Hourly
                                       0
                                     0.00%
Combination
                                       7
                                     8.97%
Not Specified
                                      14
                                    17.95%
Total
                                      78
                                       

Thermal Limits by EPA Region
                                       
                             Number of facilities
                               Percent of total
Region 1
                                       5
                                     6.41%
Region 2
                                       9
                                    11.54%
Region 3
                                      10
                                    12.82%
Region 4
                                      17
                                    21.79%
Region 5
                                      32
                                    41.03%
Region 6
                                       1
                                     1.28%
Region 7
                                       3
                                     3.85%
Region 8
                                       1
                                     1.28%
Region 9
                                       0
                                     0.00%
Region 10
                                       0
                                     0.00%
Total
                                      78
                                       

