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442 Industrial Wastewater Treatment, Recycling, and Reuse

Conductivity has poor correlation with sugar cane juice contamination
and performs poorly in providing reliable and early detection.
iii. TOC analyzers
TOC analyzers are usually based on grab sample analyses and are not
online in the “true” sense. The samples are automatically collected at
regular intervals and analyzed in a separate chamber within the instru-
ment. There are major shortcomings in such a method. For example,
even with a 5-minute response time, the TOC analyzer would miss
monitoring a lot of condensate. Additionally, the background TOC
from volatile organics could be significant and is highly variable. In
our studies, it was observed that most of the TOC in condensates is con-
tributed by ethanol, and TOC data showed large variations, even when
there were no sugars present in the condensate. This would make TOC
analyzers unreliable for monitoring sugarcane juice contamination in
condensate. These analyzers require significant amounts of reagents,
and hence, similarly to wet chemistry methods, TOC analyzers suffer
from environmental health and safety issues.

11.2.4 3D TRASAR Technology for Sugar
Non-sugar materials in the sugarcane juice naturally fluoresce (Carpenter
and Wall, 1972) and can be detected with the use of an online fluorometer
(McGillivray et al., 1997). The fluorescence phenomenon is shown using
the Jablonski diagram in Figure 11.3. In fluorescence, the fluorophore is first
excited (through absorption of a photon) from its ground electronic state to
one of the various vibrational states in the excited electronic state. A photon
is then emitted as the molecule falls to one of the various vibrational levels of
the ground electronic state (Lakowicz, 2006).
Taking advantage of the fact that sugarcane juice inherently contains
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fluorophores, 3D TRASAR Technology for Sugar has been developed
for detecting sugarcane juice carryover in condensate. The technology mon-
itors the fluorescence intensity of the condensate. A spike in the fluorescence
intensity is indicative of the presence of sugarcane juice in the condensate,
and the magnitude of the intensity is relative to the level of contamination.
3D TRASAR Technology for Sugar is fluorescence-based automation that
monitors “sugar shots” online, controls the condensate reuse, and helps
sugar mills maximize the condensate recovery to boilers (or cooling tower),
while maintaining the reliable and efficient operation of the boilers and

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3D stands for Detect, Determine, and Deliver.