outlined in AWWA EWW, or by use of a D.O. probe and an average
shall be obtained on the samples for each sampling time.
(7) A semi-log plot of the data of the D.O. deficit against time
shall be constructed. Only points between 10 and 90 percent
saturation shall be considered. A line of best fit shall be drawn
through the plotted points.
(8)
The slope of the line shall be calculated.
(9) Corrections shall be made for temperature, oxygen saturation
of the water, and the relative transfer coefficient of the water
and then the pounds of oxygen dissolved at standard conditions of
20 degrees C 68 degrees F tap water, and "O" ppm dissolved
concentration shall be computed.
(10) Should diffusers fail to produce the oxygenation capacity
required, the series of tests shall be repeated.
(11) If the required oxygenation capacity is not produced after
two test repetitions, the Contractor shall either correct the
defective unit(s) or replace them with new unit(s), and the test
procedure shall be repeated as set forth herein, until
satisfactory units are obtained.
b.
Mixing Tests:
Mixing test shall be performed as follows:
(1) Velocity measurements shall be made throughout the tank under
actual operating conditions to test for complete mixing of tank
contents.
(2) This test shall be conducted at the same time as the
oxygenation capacity test.
(3) Measurements shall be taken at the quarter points of each
tank wall, 600 mm 2 feet from the wall, and at the levels of the
sample pumps used in oxygenation capacity tests. Minimum velocity
shall be 0.18 meters per second 0.6 fps. Measurements shall be
taken with a current meter.
(4) Should any of the velocity measurements fall below the
specified minimum velocity, the test shall be repeated.
(5) If the specified minimum velocity is not produced after two
test repetitions, the Contractor shall either correct the
defective unit(s) or replace them with new unit(s), and the test
procedures shall be repeated as set forth herein, until
satisfactory units are obtained.
3.10.3.5
Hypochlorinator Tests
**************************************************************************
NOTE: Delete this paragraph when hypochlorinator is
not required. Hypochlorinator should be specified
for all plants 4.38 L/s 100,000 GPD capacity and
below. Chlorinator should be specified for all
plants 6.57 L/s 150,000 GPD capacity and above.
Between 4.38 and 6.57 L/s 100,000 and 150,000 GPD
capacity either is suitable. Selection should be
SECTION 11375N
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