Process plants need to be exceptionally aware of environmental issues and norms due
to the nature of the products that these companies deal with. Quite often the chemicals
and liquids used in these processes are toxic and even a small spill into a river or a
natural water source can spell disaster. These companies produce a toxic effluent that
is completely different from that of a municipal plant. Hence, they often have their own
Total organic carbon (TOC) content is an important element that needs to be measured
and monitored so that bio mass can sustain. The use of TOC analysers, together with
flow meters, in different production areas helps in minimising product or process loss.
Each of the production areas also becomes independently accountable for the amount
of effluent discharged.
TOC monitoring at the inlet of the treatment plant is essential to ensure excessive levels
of chemical are prevented from entering the plant. Quite often this highly contaminated
effluent is diverted to a holding tank and disposed off by specialist companies. If the
final effluent from the treatment plant is being discharged to a river or sea, then TOC
monitoring is generally used to ensure compliance.
The food industry as a whole uses large quantities of water during the manufacturing
process. The very nature of these products means that it will be very high in organic
The milk industry suffers from very high product losses. Monitoring product loss with
the help of turbidity meters has been tried for years, but without much success. Many
plants have now shifted to TOC analysers to monitor different areas of production. They
have been successful in reducing product loss by detecting when mechanical failures
occur and bad housekeeping is taking place.
The beer industry is very similar to that of the milk; they have tremendously high peak
loads in their effluent discharge. It has been proven that by using a TOC analyser and
monitoring the effluent in real time it is possible to find the causes of the high organic
discharge and significantly reduce them.
The softdrink industry uses large amounts of sugar in the production process. . Like in
other industries, a lot of product is likely to be discharged into the effluent. It is important
therefore that this industry monitors the organic level to prevent high discharges to the effluent treatment plant. This would result in financial benefits, both in terms of reduced
product loss and treatment charges.
Product Loss Monitoring
The integration of continuous water quality monitoring in production areas can be used
to identify product loss in real time. Instrumentation to monitor drains within bottling
plants, after fermenters and post CIP has been used to identify when product loss has
occurred. Events can be alarmed in real time by instruments such as the FMTOC101
Total organic Carbon analyser, so corrective action can be immediately taken.
Distillers claim that the unique taste of their whisky is due to the water that it is made
from. This water is quite often obtained from bore holes, rivers, etc. and it would
therefore be logical to monitor the quality of this water firstly to ensure that no
contamination has managed to seep into it and secondly to ensure consistency for the
quality of the product.
Surface water is another major area where TOC analysers have been used in process
industry. Tank farms, storage areas and in oil marketing terminal type complexes where
rain water is diverted to pass through the treatment works
Due to the nature of the process, some chemical plants have chemical contamination
in large amounts of water. Not only does the water need to be cleaned, the chemical
also needs to be reclaimed at the same time. This is often done by distillation where
the water is heated and the chemical evaporates. The vapor is then cooled to collect
the chemical. The TOC monitor can therefore be used at two areas in this industry.
Firstly for the water that has had the chemical removed from it and secondly for
detecting leaks in the cooling water pipe work.
TOC monitoring using UV Persulfate Oxidisation Technology
UV persulfate oxidisation is one of the most widely accepted technologies for today’s
demanding need for online TOC monitoring. The sample is simultaneously exposed to
persulfate and UV radiation and the resulting CO2 is purged by a carrier gas and
detected by NDIR. The oxidation is significantly enhanced over UV radiations, by
simultaneous ionisation of dissolved organics and production of highly reactive sulfate
radicals and hydroxyl radicals. This process also ensures that all available organic
carbon is oxidised without worry about optimisation.
The Forbes Marshall Total Organic Carbon (TOC) range of online analysers offers a
highly reliable, quick and accurate means to determine, in real time, organic
contamination in waste-water and effluent. These robust systems are supported by a
diverse range of sample acquisition and pre-treatment systems that enable reliable
monitoring of even the most difficult of effluent streams, in chemical, refinery, fertiliser
and petrochemical industries.