NC0026921_DMR DO_20011219

December 19, 2001
Memo: FRO File
Through: Paul Ra
From: Don Register
Subject: DMR D.O. Readings, Town of Parkton, NPDES NC0026921.
Roy Lowder, ORC for the Town of Parkton, called Monday, December 17, 2001 with a
concern regarding his D.O. meter. Kitty had called him because he had sent in DMR's
with effluent D.O.'s of less than 1 mg/1.. It was determined the electolyte was out of the
probe and he was not properly calibrating the meter. He was unaware that his permit had
a D.O. limit of 5 mg/1. I reviewed with him the permit limits and the proper way to
maintain and calibrate the probe, and to log it's calibration each time the meter is used. I
also recommended that he purchase a field probe to use, instead of the BOD bottle probe
that is currently used.
The DMR parameters that Roy determines is temperature, chlorine residual, pH, and
D.O.. He has been recording the calibration for each test except for D.O., and now it will
be recorded. He will list the facility as non -compliant for the month of November due to
the low D.O. readings. The D.O. has been lower than normal in the oxidation based on
the looks of the clarifier, (rising sludge and turbidity). Tuesday, the weir was raised in
the ditch approximately 2 inches to increase the oxygen transfer from the brush aerator.
The D.O. today was effluent 6.3mg/1 and ditch 1.0 — 1.8mg/1) and the clarifier clarity was
returning nicely.