Quality Control Approach to NPDES Compliance Determination
ABSTRACT: A test criterion is developed to estimate the frac
tion of noncompliance months. Typical permit effluent limits for
a pollutant are specified as a maximum monthly average and a
daily sample maximum. Values reported to the regulatory agency
by the permitee usually are limited to monthly minima, maxima,
averages, and numbers of observations. The regulator uses an
arbitrary multiple of the permit limit to judge whether the monthly
average for a pollutant is in compliance. Viewing the problem of
compliance from the perspective of statistical quality assurance,
noncompliance with a monthly average value occurs when the
fraction of defective (out of compliance) analyses in a month is
too high. J. Water Pollut. Control Fed., 60, 1436 (1988).
KEYWORDS: wastewater treatment, effluent standard, (quality
control), statistical analysis.