2.1.2.3
Nominal Average Intensity
The nominal average intensity within the channel shall be not less than
[_____] microwatts per square cm at a transmittance of 70 percent after 100
hour burn-in of lamps and with no fouling on the lamp sleeves.
2.1.2.4
UV Density
The UV density of the channel shall be not less than [_____] watts/liter.
2.1.2.5
Retention Time
The actual retention time (t) of the effluent within the system determined
by hydraulic analysis shall be not less than 0.9 times the theoretical
retention time (T). The theoretical retention time (T) shall be not less
than [_____] seconds at the peak design flowrate.
2.1.2.6
Plug Flow
The flow characteristics through the system shall closely simulate ideal
plug flow conditions under the full operating flow range. The Morrill
Dispersion Index, defined as the time required for 90 percent of the salt
and dye traces to pass, divided by the time required for 10 percent to
pass, shall be less than 2.0. The ratio of the time required for 50
percent of tracer to pass to the mean residence time shall have a value
between 0.9 and 1.1. The ratio of the time of initial tracer appearance to
the theoretical residence time shall have a value greater than 0.5.
2.1.2.7
Dispersion
The dispersion coefficient, which accounts for the deviation of the
channel's hydraulic behavior from that of perfect plug flow, shall be less
than 100 square cm per second. The dispersion number (ratio of the
dispersion coefficient to the product of flow velocity and channel length)
shall be less than 0.l.
2.1.2.8
Turbulence
Flow through the system shall be turbulent with a Reynolds Number greater
than 4,000 at average flow.
2.1.2.9
Channel Volume
Full use shall be made of the channel volume throughout the flow range.
The ratio of the mean residence time (theta) to theoretical residence time
(T) shall be greater than 0.9.
2.1.2.10
Headloss
The headloss caused by each bank of horizontal lamp modules shall be such
that at the peak flow rate no lamp is exposed to the atmosphere and the
maximum depth over the uppermost lamp sleeves is 40 mm 1.5 inches. The
headloss through vertical lamp banks shall not exceed 150 mm 6 inches.
2.1.2.11
Cross Sectional Area
The cross-sectional area occupied by the lamp module frame at the entrance
and exit of each bank shall be no greater than 35 percent of the
cross-sectional area occupied by the effluent in the channel.
SECTION 11376
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