Annelie Lourens Dr Jeremy Lucas South Australian Water Corporation

Annelie Lourens

Dr Jeremy Lucas

South Australian Water Corporation

Improving System Performance through the process of operational monitoring

Water Safety Conference 2010


Context of Experience:

Water Safety ConferenceNovember 2-4 2010, Kuching, Malaysia


Context of Experience:

• South Australia



1. Context of Experience:

• South Australia

• Australian Drinking Water Guidelines (ADWG)

• ADWG Framework

2. Types of monitoring

3. Risk based approach to monitoring Water Safety Conference

November 2-4 2010, Kuching, Malaysia

1. CONTEXT:

Water supplied by South Australian Water Corporation


Population 1.5 million people

• 1.1 million metro

• 0.4 million country

26,000 km of water mains

• 9,000 km Metro Adelaide

• 17,000 km Country SA

Country SA

• Populations range from 5 to 600,000

1. CONTEXT (Cont)

South Australian Water Monitoring Program


Metropolitan area– 1.1 million people– 6 water supply

systems

Country area– 0.4 million people– 74 Potable Drinking

Water Supply Systems and 17 Non-Potable Systems

The question of monitoring

Why bother?


1. CONTEXT (Cont)

ADWG

• The Australian Drinking Water Guidelines, (ADWG, 2004) provides guidance on the development of monitoring programs• Fact Sheets A-Z• Framework for Drinking Water Quality

Management• High level and generic guidance, based on typical

water types• Guidance designed for larger systems


2. TYPES OF MONITORING

Defined

1. Verification monitoring/ base program

2. Operational Monitoring

3. Event based monitoring


2. TYPES OF MONITORING (Cont)

Building the Monitoring Program – Factors to consider


1. Verification monitoring /base program: • generally at customer taps and with

consideration of population size• Include requirements from regulators or Dept of

Health • Include annual reporting requirements and

objectives• Consider utility’s key performance indicators

(KPIs)• Consider long-term monitoring (historical trends)

of parameters required for asset management, reviewing catchment management initiatives, monitoring drought, seasonal variation, research

2. Operational Monitoring

3. Event Based Monitoring




1. Verification monitoring /base program

2. Operational monitoring :• residual and water age management, • water treatment plant operation• Key Performance Indicators (KPIs)

3. Event Based Monitoring




1. Verification monitoring /base program 2. Operational monitoring

3. Event Based Monitoring• Targeted monitoring for a hazard when

barriers are under challenge -> protocols• Useful for parameters which are primarily rain

or event derived -> protocols• Targeted monitoring when “change” is noted

–> alarm bells should sound



3. Event Based Monitoring (cont) : 3 examples


• Cryptosporidium / Giardia – often washed in from catchment during rain events – little useful data is gathered by a set (routine) frequency

• Pesticides – often washed in from catchments during rain events – need to evaluate pesticides used in catchment

• Bore Integrity – use turbidity, nitrates and micro to determine whether bores subject to surface water intrusion during rain events




More on ....2. Operational monitoring (Continued):

1. Data quality is a major factor - can you trust the data and can you adequate manage the risk with the data?

• Data integrity (calibration, AQCs)• Timeliness – (time delays with operational

monitoring e.g. if chlorine analyser samples every 2, 5 or fifteen minutes and communication delays impacts how quickly you can respond to an incident and shut down system)

2. Combination of parameters may prove useful (e.g. if pH increases and free ammonia decreases then indicates nitrification)




2. Operational monitoring (Continued):

3. Level of alarms• if you set too high then may be too late to

react,• too low then “noise” may trigger alarm• ideally monitor trends of parameters (outlier

report)4. CCP's monitored to manage risk in a system 5. Operational monitoring should be managed with

caution:• Automation can lead to over reliance on

number s• Operational knowledge could deteriorate

(understand sampling times, error margins, alarms, reporting mechanisms)

3. RISK BASED APPROACH TO MONITORING


Caution should be taken in designing and relying on monitoring:

•Avoid over-reliance on numerical values•Adopt multiple barrier approach to ensure safe drinking water•Design monitoring program with the risk to be managed in mind

• Risk of pathogens in water (acute)- >chlorine residual->Online (continuous monitoring)

• Risk of low level chemicals in water (chronic)-> regular but less frequent monitoring

3. RISK BASED APPROACH TO MONITORING (Cont)


SA Water has adopted the following process:1. Establish a baseline monitoring program based

on barriers across each system. This involves categorising each barrier and incorporating research, infrastructure and operational monitoring requirements

2. Based on systematic risk assessment, increase the monitoring and frequency of certain parameters to monitor that risk, including event-based monitoring

3. Continuously review historical information and refine monitoring program


Assessing Risk


Risk Level Risk ADWG

VERY HIGHSignificant hazard is present in significant levels in source – system may have none or only a single barrier to control

Hazard above health criteria

HIGHSignificant hazard is present and not well controlled by system

Hazard near or just above health criteria

MEDIUMHazard is present, but not at high levels and system can control with multiple barriers

Hazard below health criteria but above aesthetic criteria

LOW Hazard may be present but easily controlledHazard well below any aesthetic criteria


Classify sources and barriers


Identify:

• Minimum monitoring requirements for each source, considering the barriers and the parameters at risk

• Those parameters only required to be monitored on an event-basis for each sub-barrier


Classify sources and barriers


Example: Classify type of Bores

• One of twenty in a field accessing the same aquifer and mixing all water in a tank prior to chlorination

• Primary bore – sole source of supply for a system

• Secondary bore which supplies only during peak demand

• Emergency bore which only supplies water if all other primary sources (bore or surface water) fail

• Newly drilled bore in a confined aquifer


Considerations


• Locating sample points so they are representative – – customer taps should be located at a range of

different locations (dead ends, areas with loops and so on)

• Regular review of customer tap locations to ensure major population centres covered (expansions)

• Sufficient numbers of sample points to ensure capture hazards appropriately (population centres, number of locations across a lake or river and so on)

• Increase monitoring at areas where there are unknowns


Surrogates and staged monitoring


• THMs as a disinfection by-product (DBP) surrogate– If high levels then scan for other DBP’s

• Algae base program; escalation to other parameters

• Hot and cold odours to capture taste and odours issues – algal blooms, health of distribution

systems, growths in storages, hydrocarbon contamination of groundwater

• Turbidity or suspended solids to measure changes in source water quality– bore integrity, reverse flow in

distribution systems


Monitoring frequency of parameters based on risk - examples


•Cryptosporidium / Giardia•Amoeba (such as Naegleria fowleri)•Pesticides•Organic chemicals•Disinfection by-products


Historical Trending


Historical trending identifies:• Changes over time• Allows comparison of seasonal changes• Measure impacts of catchment management

practices, new infrastructure, changing operation

• Drought impacts

Allows you to identify trends of parameters and whether the risk is increasing or decreasing with time


Case Studies


• Case Study #1 –Two bores supplying a tank, treated by UV at the tank outlet and supplying two towns, one of 5,000 people and the other 2,000

• Case Study #2 - A river supplying a town of 20,000 people

• Case Study #3 – A small isolated bore system to a tank feeding a population of 100 people

Case Study # 1

Two bores supplying a tank, treated by UV at the tank outlet and supplying towns of 5,000 people.


• A full set of chemistry: bore 2 has high Cd above ADWG

• Monitoring bores: monthly baseline micro + TDS

• Tank outlet: Cd when bore 2 online (summer) • UV unit - UV transmissivity• Tank – regular micro prior and post• Customer taps: – depend on configuration of

the networks; need to capture major population centres and any high risk areas (industrial, hospital, many private bore schemes, bore pipework integrity, collections of dead-ends).

Case Study # 2

A river supplying a town of 20,000 people. The water off-take is downstream of stormwater outfall.


• Event-based sampling + pesticides• Survey of river – Al, Fe, Mn above aesthetic

levels – monitor distribution system• Algal blooms - several locations upstream• The town will need a number of customer taps

depending on the shape of the town to capture major population centres, and capture range of locations (dead-ends, loops).

Case Study # 3

A small isolated bore system feeding to a tank; historical ADWG compliance; a population of 100 people


• Base program for a primary bore put in place with most chemistry once a year, and

• Regular salinity and micro• If any levels of ADWG elevated then frequency is

increased accordingly. • Simple survey of catchment ; pesticide use and

some livestock - event-based program put in place to monitor for pesticides during peak month of use; after heavy rain community person calls local utility operator and samples are taken for turbidity, nitrates, micro

Summary


• Ensure adequate verification/ base program is in place to compliment online monitoring and increase confidence in how barriers perform under varying conditions

• Understand your system, explore the unknowns and monitor to address gaps

• Use event-based monitoring to assess and manage the risk of key parameters at the optimum time

• Cost effective monitoring programs should adequately monitor risks and must not substitute a multiple barrier approach

Acknowledgement

Dr Jeremy Lucas

South Australian Water Corporation


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Annelie Lourens Dr Jeremy Lucas South Australian Water Corporation