Monitoring Organics in Water for Reuse




Water is used in many industrial processes for a wide
variety of applications including washing, diluting, cooling,
heating, transporting, sanitizing and processing. So much
water is required for these processes that the cost of
the water as a raw material for the plant is becoming an
increasing concern especially with growing water scarcity
around the world.
To combat the growing cost of water, industrial plants
are looking more and more to improve how they are
using this resource in their various industrial processes.
One important way for plants to reduce their water
consumption is to reuse as much water as they can.
Water reuse allows water that would have otherwise been
discarded to instead be used either again in its original
process or for another process in the plant.

CONCERN OF WATER QUALITY
One of the biggest problems with water reuse is water
quality. Water reuse requires the plant to use water
that is almost always of lesser quality than new water.
Contamination of the water with oils, chemicals, metals
and organic matter and even with the product being
produced or processed can lessen the water quality
substantially. The type of contamination as well as the
level and variation of contamination will dictate what type
of processes the water can be reused for, as well as what
type of treatment may be necessary before the water is of
high enough quality for reuse.

THE BENEFIT OF ORGANICS MONITORING
Although there are several potential types of
contamination that can be found in sources of water for
reuse, of particular interest in a number of applications
is contamination with organic matter. There are several
possible sources of organic contamination of water
reuse sources including environmental contact, leaking
heat exchangers and product loss, often leading to
varying levels of organics as well as unexpected organic
contamination events. Continuous monitoring of water
reuse sources for organic contamination can therefore be
invaluable for effective water reuse programs.

COMMON REUSE APPLICATIONS WITH
ORGANIC CONTAMINATION
There are often multiple potential sources of water for
reuse in an industrial plant. One of the most common
sources of reuse water is condensate. Depending on
the particular industrial process, condensate water can
be valuable is several ways. Condensate often comes
from boilers designed to supply steam to heat various
types of processes. The efficiency of this system relies
on the system’s ability to return the condensed steam
to the operation cycle. This allows the plant not only to
recover the used water, it also allows energy savings since
the condensate usually retains a significant amount of
heat which is recovered along with the water. Since the
condensate can become contaminated with organics
often via the heat exchanger, monitoring the water quality
for organic contamination can prevent corrosion from
occurring in the system.

REALTECH.CA
Another source of condensate for reuse is evaporators.
Evaporators are often used in the food and beverage
industry for product concentration. Essentially the
product is boiled to extract the water resulting in
concentrated product. Evaporation is a commonly used
method of product concentration in the production of
certain dairy products, juice products and even some
liquor products. The evaporated water is then condensed
and although it is often fairly clean it can contain varying
levels of organic contamination due to product loss from
the evaporation process. Monitoring these organics can
help determine the potential of evaporator condensate
for reuse purposes. In many cases, the condensate can
be reused in boiler systems with some treatment. By
monitoring the organics the operator is able to make
decisions about whether to send the condensate to
boilers as makeup water, or simply to divert to drain if
the contamination is deemed too high.
Yet another common source of water for reuse is RO
permeate from product separation processes. Organic
contamination is especially prevalent in this application
and therefore this source will require some further
treatment to be fit for most reuse applications. Unlike
the condensate water, RO permeate does not possess
any heat energy and therefore it is not as suited to boiler
reuse applications. Instead RO permeate is better reused
for applications such as wash water or cooling tower
makeup water. Monitoring organics is essential to validate
the quality of RO permeate water for reuse applications.

REAL-TIME ORGANIC MONITORING SOLUTIONS
Organics monitoring requirements can vary from
occasional grab samples to real-time continuous
monitoring. For some processes, the water quality is
so consistent that real-time monitoring is not deemed
necessary. However, if the process producing the water
results in a varying amount of contamination, or if
contamination tends to occur as sudden and sporadic
events then real-time monitoring becomes more valuable.
Due to the complexity and expense often associated with
traditional Total Organic Carbon (TOC) instrumentation,
real-time monitoring of organics is often overlooked.
However, organic contamination can easily be monitored
in real-time with the latest generation of photometric
and spectrophotometric instruments and with much less
expense and maintenance. Spectrophotometric analysis
also brings the advantage of being able to distinguish
multiple types of contamination with a single real-time
instrument. These new analyzers can rapidly detect the
most trace amount of contamination, even at ppb levels.
Using these latest spectrophotometric instruments, realtime
monitoring of organics for water reuse applications
is both convenient and cost-effective, allowing for proper
control of water reuse.

CONCLUSION
Water reuse allows cost savings due to reduced raw
water consumption, lowered treatment costs of raw water,
and reduction in energy consumption when reusing
condensate water. For proper implementation and
operation of water reuse in an industrial plant, it is often
essential to monitor the quality of the water, including
organics, since the sources of water for reuse so often
have significant levels of contamination. By monitoring
organic contamination levels in process effluents, effective
water reuse can be achieved thereby significantly
improvingthe efficiency and cost effectiveness
of industrial facilities.


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