AUTOMATIC METHODS IN WATER TESTING
THE ROLE OF LABORATORY AND ON-LINE AUTOMATED SYSTEMS
For the sake of the environment, world health and improvement
in living standards water quality is vital, and the role of automation
in today's water laboratories is becoming more significant. Because
of the range of pollutants that affect our rivers, lakes, fresh
and sea water sources an ever increasing volume of water samples
needs to be regularly examined. Soil, sewage and food products
must undergo a similar stringent control to meet the established
international standards. So it is not surprising that there is
continual world-wide demand for modern test equipment.
Many types of analysis instruments are offered for water quality
test procedures both in the laboratory and for remote on-site monitoring
stations. The choice is often one of Segmented Flow continuous
analysis, Flow Injection, Chromatography or Electrode techniques.
Most would agree that continuous analysis by segmented flow analysers
(SFA), Flow Injection (FIA) and Electrode techniques (ISE) have
shown this type of instrumentation to be perhaps the most reliable
and cost effective for routine sample analysis. The flexibility
of the systems enable both large and small sample batches to be
processed with equal convenience.
Based in the UK and providing a comprehensive range of instruments
for automatic analysis, Burkard Scientific's policy is to study
carefully the needs of the operator while maintaining the strict
requirements of present day water testing. For the technician,
this means that the equipment should be attractive to use and easy
to operate. The instruments should be designed for long life with
minimal servicing. For the water consumer, there is the assurance
of reaching the specified limits of detection. Impurity down to
parts per billion is the norm for many samples regularly examined.
The analytical capability is continually under review together
with the chemistry methodologies, to comply with the changing international
standards.
SERIES 2000 ANALYSERS
Burkard Scientific Series 2000 analysers are the well proven continuous
flow analysers. They have been installed world-wide for use in
Water, Forestry, Agriculture and Atmospheric Pollution laboratories
in heavy industrial areas. The degree of sophistication will depend
on a variety of factors including the type and concentration of
the analyte under test, as well as the size of the batches being
analysed.
As the systems are modular they have many attractive features.
Each unit of a system benefits from the latest technology and lends
itself to updating without major reconstruction. Again, individual
components make for the utmost flexibility where a combination
of Sample Changer capacity, number of analytical channels, pumping
capacity, and type of chemistry detection can be selected to suit
the user's needs. Daily testing not only involves the setting up
of the analysers, but in large laboratories where the work load
is considerable, data processing is an essential element to full
automation. The Burkard MicroStream is one such data base which
enhances the power and performance of any system.
MicroStream is a 4 to 16 Channel model in a range of PHA peak
height analysers designed for processing signals from analytical
equipment which are fed with material from automatic samplers.
The data system runs in real time, performing all peak analysis
and calculations 'on the fly'. It can be attached to practically
any equipment where samples are presented to the system at regular
intervals. It is particularly suitable for continuous-flow analysers.
MicroStream is capable of being used as a Systems Manager to start
up and close down an analyser at set periods during the day unattended.
It is the product of 15 years' experience with the water industry.
NEW ANALYTICAL METHODS
Burkard Scientific constantly addresses the new problems presented
by industrial processes in the form of effluents. Detergent levels
in rivers are regularly a cause for concern where the European
standard has been set at 250µg/litre.
In this situation a method was developed to overcome time-consuming
manual testing, which normally processes samples at rates of 10
to 15 per day. A new automated approach to the analysis involving
considerable method development was undertaken. The anionic detergent
complexes with methylene blue in alkaline solution to produce a
blue complex which is extracted into chloroform. The extract is
then washed with an acid solution of methylene blue before being
measured at 660nm using a colorimeter. Figure 1 shows the standards
and calibration graph for the range 20-250 µg/l. Analysis
times are now reduced to 20 samples per hour with a much reduced
technician time, making the test a routine undertaking.
For tests such as Phenols, Cyanide and Fluoride from water and
contaminated land samples an 'on-line' distillation facility is
offered with U.V. digestion.
HELPING THE BRAZILIAN RAIN FORESTS
The Amazonian Rain Forests are yet another example of use of the
use of the Series 2000 systems. A joint Anglo-Brazilian project
to assess the presence of soil nutrients in a forest management
scheme was set up in Manaus.
A 4-channel analyser is operated by local technicians to look
at nutrient parameters such as Boron, Phosphorous, Aluminium and
Ammonia. It is expected that the information gathered here will
make a valuable contribution to maintaining forests in this area.
OFF SHORE ACTIVITIES
Environmentalists and governmental departments concerned about
pollution of the oceans and waterways need to be kept updated on
the state of sea water. Series 2000 analysers provide data on nutrient
levels and are used by Oceanographic Scientists for survey work
in all parts of the world.
Year by year there is an increasing awareness of the urgent need
to keep our waters pure. Yet, year by year contamination increases
both in strength and complexity. Demands on laboratories are increasing
and higher standards of detection are demanded. For the foreseeable
future, continuous flow systems will play their part in the modern
laboratory where sometimes less sophistication is more successful
and cost-efficient.
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