Current through 2024-13, March 27, 2024
Using the procedures in this Section, the department shall
establish interim average and maximum effluent limits for the concentration of
mercury discharged by each licensee identified pursuant to Section
1(C). These limits
must be based upon and no less stringent statistically than past discharge
levels as determined through testing required by Section
3.
A.
Timing. The department shall
establish interim effluent limits after the minimum number of tests required in
Section 3 have been completed.
B.
Procedures.
(1) Average limits.
The department shall determine the interim average effluent limit for each
licensee, as an average concentration, as follows. Using all valid test results
for each licensee, a value equal to the standard error of the mean is added to
the mean effluent concentration. The standard error of the mean is determined
from the test results for each licensee by computing the standard deviation and
dividing that value by the square root of the number of tests done. This value
will be adjusted with a multiplier to reflect a 95% level of
probability.
(2) In the event that
the interim average effluent limit as calculated above is less that 4.5 ng/L
for an individual licensee, that licensee will be assigned an interim average
effluent limit of 4.5 ng/L.
(3)
Maximum limits. The department shall determine the interim maximum effluent
limit, as a maximum concentration in any sample, as follows. The interim
average effluent limit as determined in (1) or (2) above shall be multiplied by
a factor of 1.5 to establish the interim maximum effluent limit.
(4) Additional information. Individual
licensees may submit additional information for the department's consideration
in setting interim effluent limits. Such information may include reductions in
flow due to water conservation plans, seasonal variations and changes in levels
of production. The department may adjust interim effluent limits accordingly if
it determines that this information would significantly change the effluent
variability as determined pursuant to this section.
C.
Notification. Upon
determination of interim effluent limits, the commissioner shall notify the
licensee in writing.
