Environmental Engineering Reference
In-Depth Information
the monitoring of water samples to detect toxicity or contamination. Many of
the major monitoring tools that can be used to identify anomalies in process
streams or finished water that may represent potential threats are discussed,
including
• Sensors to monitor chemical, biological, and radiological contamination
• Arsenic measurement systems
• Biochemical oxygen demand (BOD) analyzers
• Total organic carbon analyzers
• Chlorine measurement systems
• Portable cyanide analyzers
• Portable ield monitors to measure volatile organic compounds (VOCs)
• Radiation detection equipment
• Radiation detection equipment for monitoring water assets
• Toxicity monitoring and toxicity meters
Water quality sensors may be used to monitor key elements of water or
wastewater treatment processes (such as influent water quality, treatment
processes, or effluent water quality) to identify anomalies that may indicate
threats to the system. Some sensors, such as sensors for biological organ-
isms or radiological contaminants, measure potential contamination directly,
while others, particularly some chemical monitoring systems, measure surro-
gate parameters that may indicate problems in the system but do not identify
sources of the contamination directly. In addition, sensors can provide more
accurate control of critical components in water and wastewater systems and
may provide a means of early warning so the potential effects of certain types
of attacks can be mitigated. One advantage of using chemical and biological
sensors to monitor for potential threats to water and wastewater systems is
that many utilities already employ sensors to monitor potable water (raw or
finished) or influent/effluent for Safe Drinking Water Act (SDWA) or Clean
Water Act (CWA) water quality compliance or process control.
Chemical sensors that can be used to identify potential threats to water
and wastewater systems include inorganic monitors (e.g., chlorine analyzer),
organic monitors (e.g., total organic carbon analyzer), and toxicity meters.
Radiological meters can be used to measure concentrations of several differ-
ent radioactive species. Monitors that use biological species can be used as
sentinels for the presence of contaminants of concern, such as toxics. At the
present time, biological monitors are not in widespread use and very few
biomonitors are used by drinking water utilities in the United States.
Monitoring can be conducted using either portable or fixed-location sen-
sors. Fixed-location sensors are usually used as part of a continuous, online
monitoring system. Continuous monitoring has the advantage of enabling
immediate notification when there is an upset; however, the sampling points
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