- Several references are available that provide detail about rapid or on-line monitoring techniques for the water industry (e.g., Frey and Sullivan, 2004; Gullick et al., 2003; Gullick, 2003; Hargesheimer et al., 2002; Grayman et al., 2001; Dippenaar, et al., 2000; Pollack et al., 1999).
- Design of early warning systems is also discussed in various references (e.g., Grayman et al., 2004; Gullick et al., 2003; Gullick, 2003; Grayman et al., 2001; and references therein).
- A thorough review of the types of monitors used in numerous early warning monitoring systems and networks throughout the world is provided by Grayman et al. (2001).
- Information on water quality monitoring is also available from the intergovernmental National Water Quality Monitoring Council , the USEPA , and links referenced therein.
Rapid response to spills and other sudden changes in source water quality is necessary to protect water consumers from potentially harmful contaminants, determine appropriate changes in treatment strategy, and ensure compliance with environmental regulations. Early warning monitoring systems can provide a means to monitor short-term and long-term changes in water quality, and are an essential component of any rapid response program. A source water protection program can reduce the probability of spills occurring, while early warning notification of a contamination event allows utilities to respond appropriately to reduce potential adverse impacts, including possibly shutting intakes or adjusting their location, switching to an alternate source, adjusting or adding treatment processes, and increased monitoring. Rapid or continuous real-time early warning monitoring can be used to detect accidental releases of certain contaminants as well as contaminant sources that have not been identified or properly controlled.
The primary goals of early warning monitoring systems are to allow operators to prepare for, detect, and respond to water quality changes such that public health is continually protected. Early warning and real-time monitoring can be incorporated as part of a utility's strategy for dealing with AFO contaminant releases, as well as releases from other contaminant sources. Perhaps the greatest potential for significant sudden change in surface water quality caused by a CAFO is breach of a large liquid waste storage facility.
The scope of an early warning monitoring program will depend on site-specific characteristics. For more sophisticated systems, such as ones that link several water utilities in a large river basin, organizational, institutional and communication infrastructures also need to be developed for managing and disseminating the information. Certain components, however, are generic to all good early warning systems, and include:
- Detection (a mechanism to detect pollution events)
- Characterization (a means to characterize the event)
- Communication (of data to utility personnel and other decision makers, of response actions to the public, etc.)
- Response (actions that minimize the potential impact of the contamination event)
Contaminant event detection mechanisms may include physical, chemical, microbiological and radioactive analyses, biomonitoring (bioalarms), physical observations, and reporting by other parties. The analytical monitoring methods seek to identify and quantify either a specific water quality parameter, or a surrogate parameter selected to provide a conservative indication of the presence of a more harmful contaminant. They include simple physical analyses such as turbidity, conductivity, and odor tests, relatively simple analytical tests for chemicals (e.g., specific ion electrodes for pH, nitrate and other ions; fluorescence for oils; immunoassays for herbicides), more advanced monitoring for chemicals (e.g., chromatography and mass spectrometry methods), and microbiological methods. However, the identification and quantification methods for many microbial contaminants are not very rapid, and real-time monitoring devices are not currently available for many of these.
Bioalarm systems use living organisms (e.g., bacteria, algae, zooplankton, bivalves, fish) as sensors for extreme changes in water quality, but do not indicate the specific cause. Physical observations can detect visually-observable changes in water quality (e.g., oil sheens), and can include visual inspection or video surveillance of intake water or potential contaminant sources. Reporting by other parties can include notification of spill events by local, state or federal agencies, by the dischargers themselves, or by the observing public.