All sampling, measurements, tests, and analyses of the characteristics
of discharges to the POTW shall be performed in accordance with the
procedures approved by the U.S. EPA contained in 40 CFR Part 136.
If, as determined by the Director, the sampling and analytical techniques
contained in 40 CFR Part 136 are not available, do not apply to the
discharge or pollutants in question, are not appropriate under the
circumstances for application to the discharge or pollutants in question,
or where one or more alternate techniques are available under 40 CFR
Part 136, sampling and analysis shall be performed using validated
sampling and analytical methods and procedures approved or required
by the Director.
Users shall sample their discharges to the POTW at a frequency
necessary to assess and assure compliance with the requirements of
this chapter, any permit or order issued pursuant to this chapter,
all applicable pretreatment standards and requirements, other applicable
state and federal laws and regulations, or as otherwise determined
necessary by the Director consistent with the purposes and intent
of this chapter. At a minimum, all significant industrial users shall
sample their effluent two times per year (once every six months) or
as often as provided by their permits, whichever is more frequent,
and report the results to the POTW. Each discharge point to the POTW
shall be sampled and reported individually.
Where representative samples are required to be taken for facilities
for which historical sampling data does not exist (or if otherwise
requested by the Director), a user shall take a minimum of four grab
samples for pH, temperature, cyanide, phenols (T), residual chlorine,
oil and grease, sulfide, and volatile organics (and any other parameters
designated by the Director), unless a greater number of grab samples
is required in advance by the Director. For facilities for which historical
sampling data is available, or under other circumstances determined
appropriate by the Director, the Director may authorize a lower minimum
number of grab samples (except that historical data shall not be used
for periodic compliance reports as required by § 28-08.02).
In all cases, users shall take the minimum number of grab samples
determined necessary by the Director to assess and assure compliance
by users with applicable pretreatment standards and requirements.
Grab samples may be required to show compliance with instantaneous
minimum or instantaneous maximum discharge limits. For all other pollutants
and sampling, twenty-four-hour composite samples must be obtained
through flow-proportional composite sampling techniques, unless time-proportional
composite sampling or grab sampling is authorized by the Director.
Where time-proportional composite sampling or grab sampling is authorized
by the Director, the samples must be representative of the discharge
and the decision to allow the alternative sampling must be documented
in the Industrial User file for that facility or facilities. Using
protocols (including appropriate preservation) specified in 40 CFR
Part 136 and appropriate EPA guidance, multiple grab samples collected
during a twenty-four-hour period may be composited prior to the analysis
as follows: for cyanide, total phenols, and sulfides the samples may
be composited in the laboratory or in the field; for volatile organics
and oil and grease, the samples may be composited in the laboratory.
Composite samples for other parameters unaffected by the compositing
procedures as documented in approved EPA methodologies may be authorized
by the Director, as appropriate.
All required monitoring, taking of samples, and sample analyses,
whether performed by the Director or by a user, including, but not
limited to, the costs or fees associated with inspection or surveillance,
shall be at the sole cost of the user. For users with more than one
outfall, each outfall monitored shall be charged separately.
The Director may use any of the following methods to determine
the amount of wastewater flow discharged to the POTW from a user's
premises, as determined appropriate by the Director:
A. If the premises are metered, the amount of water supplied to the
premises as shown by the water meter;
B. If the premises are supplied with river water or water from private
wells, the Director may estimate the amount of water supplied from
such sources based on the water, gas or electric supply to the premises,
or may require that the water flow be measured using a certified meter
approved by the Director;
C. If the premises are used for an industrial or commercial purpose
of such a nature that the water supplied to the premises cannot be
(or is not) entirely discharged to the POTW, the Director may estimate
the amount of wastewater discharged to the POTW based on the water,
gas, or electric supply to the premises;
D. The Director may determine the amount of wastewater discharged to
the POTW based on measurements and samples taken by the Director from
a manhole installed by the owner of the premises, at the owner's
sole expense, as required by the Director under this chapter;
E. The Director may require a wastewater flow meter in a manhole installed
by the owner of the premises, at the owner's sole expense; or
F. The Director may determine the amount of wastewater discharged to
the POTW from a premises using a combination of any of the above methods,
or using any other method determined appropriate by the Director.