521-OM0108.88
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2009 Nalco Company
6-32
Technical Help
(630) 305-CHEM
3D TRASAR
5500 - Installation & Operation Manual
25. Can you give me an example where 3D TRASAR Bio-Control varied the Oxidant
feed based on system demand?
In this tower oxidizing biocide is STA-BR-EX. Tower is under 3D TRASAR Bio-Control. On 8/23/04
the tower is slugged with 6 ppm of N73550 (biodetergent). Entire system (deadlegs, unused
towers, unused chillers) is opened up to detergent. 100 ppm of N7330 is added to the tower 1 hr
later. As untreated and sloughed up biofilm is exposed, the Nalco Bio-Index increases and the
duration and frequency of the oxidizing biocide feed (Ox pump On time) is increased. The Nalco
Bio-Index has a double-humped profile (second peak on 08/24/04) due to the detergent continuing
to slough off deposits while the N7330 concentration is reduced by consumption and blowdown.
System is finally brought back to normal levels of STA-BR-EX feed by 08/25/04 at which time it is
treated to 50 ppm of N90005 (quaternary amine algaecide). The algaecide is also a surfactant and
a slow acting bactericide. There is an initial increase in Nalco Bio-Index followed by a 21 hr period
during which no STA-BR-EX is fed into the tower. Compare this to normal operation period (08/20/
04-08/22/04). The consecutive application of two non-oxidizers led to low microbiological activity
and consequently a 21 hr period of no oxidant feed into the system. Planktonic counts taken on
08/26/04 show good microbial control.
0
50
100
150
200
250
300
8/20/04
8/22/04
8/24/04
8/26/04
8/28/04
Ox Pump on sec/600s
-15
-10
-5
0
5
10
15
20
25
30
3D Bio Index
Ox_pump_ on_time
BF_ratio_ index
N73550 &
N7330 slug
N90005 slug
No Ox feed
for 21 hrs
26. How do I determine how much Bio-Reporter to use?
The bio-reporter is applied by the controller to maintain 20 ppb of active product. There is some
consumption of the bio-reporter molecule during each blowdown cycle. The product usage per unit
blowdown can range between 30-120 ppb (active), while a typical usage concentration is 60 ppb
(actives) per unit blowdown. The concentration of the bio-reporter used in a tower per unit
blowdown is a function of several factors including: HTI, microbial activity, biocide, tower configu-
ration, etc. The chart below can be used to obtain an initial estimate of how much of the bio-
reporter product to order. The quantity of bio-reporter can also be obtained by looking at the 3D
TRASAR Optimizer report.
Bio-Reporter
lbs/Million gal of
blowdown
3DTBR06
83.4
3DTBR8
6.3
3DTBR20
2.5
3DTBR40
1.3
3DTBR10
5.0
