9.4.1 Operational characteristics

The characteristics selected for operational monitoring should provide useful information concerning operational activities and performance and to confirm the effectiveness of preventive measures and barriers. It is common, particularly in monitoring the operation of treatment processes, to use surrogates or indicators for water quality characteristics when direct testing is difficult, time-consuming or expensive.

Table 9.1 provides examples of characteristics commonly used for operational monitoring, by location from catchment to consumer.

Table 9.1 Examples of operational monitoring characteristics

Operational monitoring characteristics#	Stages of Water Supply and Treatment Processes - Source water	Stages of Water Supply and Treatment Processes - Coagulation /Flocculation	Stages of Water Supply and Treatment Processes - Clarification (Sedimentation/Flotation)	Stages of Water Supply and Treatment Processes - Filtration (Media/ Membrane)	Stages of Water Supply and Treatment Processes - Disinfection (Chlorine/ UV) Post Chemical Dosing	Stages of Water Supply and Treatment Processes - Distribution system
pH	✓	✓			✓	✓
Turbidity (or particle count)	✓		✓	✓	✓	✓
Temperature#	✓		✓	✓		✓
Dissolved oxygen	✓
Stream or river flow#	✓
Rainfall#	✓	✓	✓		✓
Escherichia coli (E. coli)	✓				*	*
Alternative microbial faecal indicators	✓
Total coliforms					✓	✓
Heterotrophic plate count (HPC)					✓	✓
Colour	✓		✓		✓
Conductivity (total dissolved solids)	✓
Alkalinity#	✓	✓			✓
Organic carbon#	✓
Algae, algal toxins and metabolites	✓				✓
Chemical dosage#		✓			✓
Flow rate#		✓			✓
Net charge#		✓
Streaming current value#		✓
Headloss#				✓
C.t^					✓
UV calculated dose#					✓
UV intensity#					✓
UV transmissivity#					✓
UV lamp age#					✓
Disinfectant residual#					✓	✓
Flux#				✓	✓
Transmembrane pressure (TMP)#				✓
Membrane integrity test (pressure based test)#				✓
Hydraulic pressure#						✓
Tank integrity#						✓

# Many of the characteristics list in this Table do not have Fact Sheets, or guideline values, but relate directly to the operation of water treatment processes which are beyond the scope of the current Guidelines to describe. Many of these characteristics will be supply-system specific, and not amenable to the setting of guideline values. Further information on these characteristics should be sought from water treatment experts

^ C.t = a measure of free chlorine residual concentration (C) and contact time (t)

* Monitoring for E. coli is typically undertaken at these locations as part of a drinking water quality monitoring program, but may be used to inform operational decisions.

In addition to field measurements, grab sampling for laboratory analysis, and online instrumentation, observational monitoring can also provide information on system challenge and barrier performance. Routine observational monitoring should be in place from catchment to consumer to identify and confirm, for example:

• the general level of activity in the catchment and/or reservoir, any illegal activities and sources of contamination, and the effectiveness of preventive measures such as gates, fences and signs;

• the security of the water treatment plant and chlorination facilities;

• that the chemicals used in water treatment are appropriate (see Chapter 8);

• the integrity of dosing and ancillary equipment;

• the performance of treatment processes such as effective floc formation, bubbling in granular filters, membrane integrity;

• the integrity of service tanks or reservoirs and the pipe network; and

• that routine preventive maintenance is undertaken throughout the system.