INSTRUMENTATION: WATER AND WASTEWATER ANALYSIS 539
dissolved oxygen content is greatly reduced and anaero-
bic conditions develop. Another category of pollution are
the toxic substances entering water bodies, such as some
synthetic organic materials and toxic metals and non-metals:
they cause the death of aquatic plants and animals disrupting
the water ecosystem. Non-biodegradable substances may be
toxic, cause problems due to their physical nature, or detract
from the beauty of nature.
From a consideration of the foregoing descriptions of the
mechanisms of pollution effects, a number of parameters for
the determination and control of water pollution can be listed.
For example degradable organic matter, non-biodegradable
substances, dissolved oxygen, nitrates and phosphates, and
toxic metals, non-metals and organic matter are classes of
substances requiring methods of analysis.
However the previous and rather bare outline of the pol-
lution scenario does not expose the complex problems in
describing the ecological mechanisms affected by pollution
and their attendant solutions. The definition of a problem is
necessary if one is to prescribe a solution. The more com-
plete the definition, the more precise and comprehensive the
proposed interpretation can be. Unfortunately, we do not
have the luxury of unlimited time to adequately define the
various environmental problems; we must institute actions
using the knowledge at hand and update and improve our
interim solutions as we approach a more complete definition
of each of the problems. Indeed, the answers to the problems
of water pollution and abatement have been undertaken in
this vein.
The large question, what do we measure, brings us to the
complexity of the issue, since what we measure is connected
to why we measure a particular property or component. The
attempt to answer these questions cannot be undertaken in
this relatively short article, however, a very limited response
will be given to these questions.
This article will describe the operation and use of
chemical instrumentation both in the laboratory and in
monitoring instrumental systems, for data collection nec-
essary for refining the definition of the environmental
water problems, monitoring of processes to treat waste-
waters and drinking water, and the ecological monitoring
of natural waters.WATER AND WASTEWATER ANALYSISIn the last fifty years the advances in electronics have made
possible the development of the sophisticated instrumenta-
tion and computer systems which serve very well the pur-
poses described herein. Development of chemical sensors
and their combination with instrumentation has resulted in
the laboratory and monitoring chemical measurement instru-
ments so commonly found in laboratories, environmental
monitoring systems and manufacturing plants. In addition
the interfacing of these instruments and computer systems
results in effective and creative data handling, computation,
and prediction.A general consideration of the analysis of water and
wastewater samples brings forth several factors to consider.
What characteristics need to be monitored and for what
reasons? How do we obtain a representative sample of
the source to be analyzed and how do we preserve its
integrity until an analysis is completed? What constitutes
our present methodology and with what biological, chemi-
cal, physical and instrumental means do we carry out
these measurements? However, a primary consideration in
answering these questions relates to the nature of water
and wastewater samples.The Nature of Water-Related Samples and Sampling
ConsiderationsNature of Water-Related Samples The category of water
and wastewater samples can include water samples, sludges,
benthic muds, plant matter and so forth. Samples may be
taken from a number of systems: for example, natural water
bodies, process streams from wastewater treatment and
manufacturing plants, benthic environments, marshes, etc.
Different procedures for sampling can be required for each
variety of sample based on their unique chemical, physical,
and/or biological nature.
Water is alluded to as the universal solvent for good
reasons; it is the best solvent humans experience. In addi-
tion to dissolved substances water can also transport insol-
uble, suspended, and/or colloidal matter. Thus, a sample
can contain components in a number of physical states:
i.e.; dissolved, in ionic and molecular form; insoluble, as
are bubbles of gas, and suspended and colloidal chemical
substances; and biological organisms in a variety of sizes.
The determination of the identity and concentration of
unique chemical and biological components is important.
The presence of these components give to the water sample
biological, chemical, and physical characteristics—such as
physiological qualities, acidity, alkalinity, color, opacity and
so forth.
Sludges and mud samples are heterogeneous mixtures
containing water with dissolved matter and the sampling
procedure must not change the composition of the mix-
ture. Plant matter, having its own unique characteris-
tics, requires the proper procedures for sampling.^1 Many
samples display time-based changes once taken from the
source for a host of reasons. Changes are evident over
various time scales. For example suspended matter settles
during a time period as determined by particle size giving
a change in opacity and/or color, chemical reactions may
occur amongst components, gases and volatile substances
may diffuse to the surface of the sample and evaporate,
gases or volatile substances in the air space above the
sample may condense and dissolve at the sample interface,
etc. Substances in benthic samples can experience air oxi-
dation and plant matter can lose moisture and so forth. All
of these changes present a deviation of the sample’s com-
position and characteristics from the source. The serious-
ness of the changes depend on the purpose of the analysisC009_005_r03.indd 539C009_005_r03.indd 539 11/23/2005 11:12:19 AM11/23/2005 11:12:19