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Sydney Water Annual Report 2009
Performance review: Providing clean, safe drinking water
 
From this summer, water from the desalination plant will reach up to 1.5 million people as part or all of their water supply.
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In this section:

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Maintaining high water quality and preparing for the future

In 2008–09, Sydney Water supplied over 487 billion litres of water to 4.3 million people in 1.7 million homes and businesses. This was about one per cent more than the previous year and was mainly due to a return to drier weather conditions.

Sydney Water buys raw water from the Sydney Catchment Authority (SCA). The water is then treated and distributed to customers via a network of about 21,000 km of water mains, 263 reservoirs and 162 pumping stations.

A key objective under the Sydney Water Act 1994 is to protect public health by supplying clean, safe drinking water. Sydney Water’s Operating Licence requires Sydney Water to comply with the Australian Drinking Water Guidelines. During 2008–09, Sydney Water achieved 100% compliance with its Operating Licence conditions.

Throughout 2008–09, Sydney Water tested almost 7,800 samples from customer taps. Water is tested for a range of organic chemicals, metals and micro-organisms as well as disinfectant levels and water clarity. The water quality monitoring plan is agreed with NSW Health.

Water from the desalination plant

From this summer, water from the desalination plant will reach up to 1.5 million people as part or all of their water supply. Water from the plant will meet the Australian Drinking Water Guidelines and can provide up to 250 million litres of water a day – 15% of Sydney’s water needs.

Researching more accurate parasite tests

Sydney Water routinely tests for Cryptosporidium and Giardia. The water filtration plants filter and disinfect the drinking water to remove these and other parasites that can be found in water.

Five years ago, Sydney Water started research at its West Ryde laboratory on improved testing methods. One test quickly screens for the broad range of Cryptosporidium species. The second test detects the two main species of Cryptosporidium known to cause water borne disease outbreaks.

In February 2009, the laboratory was audited for National Association of Testing Authorities accreditation for a Cryptosporidium viability test, which can determine whether organisms are alive or dead. This involved an assessment to demonstrate that the test results are accurate when done on a routine basis. Accreditation was recommended and approval is expected in early 2009–10.

Progress on Blue Green Algae Action Plan

Sydney Water and Sydney Catchment Authority developed the Warragamba Dam Blue Green Algae Action Plan, following the algal bloom on the dam in late 2007. As the catchment manager, Sydney Catchment Authority is the lead agency on the plan.

During 2008–09, Sydney Water completed most of its actions, including plans to:

  • manage taste and odour compounds from blue green algae
  • remove algal toxins in the event of a severe algal bloom.

New water modelling leads to savings

Sydney Water started using new water modelling software in 2007 to decide the best pipe sizes for the amount of water and water pressure needed. This leads to savings in building new water, wastewater and recycled water services as smaller pipes can be used.

The water models are linked to Sydney Water’s billing and corporate information systems so water use patterns can be accurately calculated for each area. Sydney Water can check the capacity of pipes, pumps and reservoirs and can test for pipe failure and the stress of extreme events on the system.

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Feature:
Learning from the best at home and overseas

Michael Storey is a Project Manager in Sydney Water’s Science and Technology team. They are responsible for scientific, research and development projects.

‘In June and July 2008, I visited researchers and utilities in Europe and the US to investigate world’s best practice in online monitoring techniques. I spent some time in the Netherlands and with the US Environmental Protection Agency and Department of Homeland Security.

‘I saw first-hand how major utilities deal with water quality testing and was able to explore new tools and techniques. Sydney Water compares well internationally as we already have some online monitoring systems in place, including chlorine monitors on reservoirs and water filtration plants.

‘We are now trialling some of the tools that I saw used overseas. One is a tool that checks drinking water quality at customers’ meters. Another is a system that measures the light scattering properties of wastewater. This system will enable us to check changes in wastewater quality. This is important as it can reduce corrosion in pipes and protect the health of sewer workers.

‘With these new online monitoring tools, we can make sure that Sydney’s water and wastewater systems can continue to protect public health into the future.’

Michael Storey explains his online monitoring research

Michael Storey explaining his online monitoring research

High satisfaction with water quality

Customer satisfaction with water quality remained high. Sydney Water’s annual Customer Relationship Study showed an improved level of customer satisfaction with the overall quality of drinking water supplied. On a scale of 1–10 where 10 is excellent, the average rating in 2009 was 8.0 out of 10. This is an improvement on the 7.7 rating for the previous two years.

Managing critical water mains

During the year, Sydney Water maintained and renewed various water system assets. About 108 km of reticulation water mains were replaced along with six km of critical water mains. In the previous five years, over 550 km of water mains were renewed, which is equivalent to almost three per cent of the entire water main network.

Staff assess the need for repairs in high-risk and critical pipes. This takes into account the age of the asset, changes required to improve the reliability of the system and repairs needed for operational, health or safety reasons.

Sydney Water closely monitors assets that are critical to the ongoing running of the system and to maintaining levels of customer service.

Bellevue Hill incident

In some situations it is not possible to predict the failure of an underground critical water main. For example, in May 2009 a critical water main in Bellevue Hill ruptured and this led to the collapse of a 25 metre section of roadway into Cooper Park.

The main had not had any faults before and was in relatively good condition with only minor corrosion. However, a leak developed on this main that was too small to trigger the alarm on the reservoir control system. A member of the public reported the leak to Sydney Water. By mistake the Sydney Water crew was sent to the wrong location.

When the crew did arrive two days later, they listened for any possible leak with acoustic equipment. A small leak in a large main can be difficult to identify and the problem was missed. They concluded that the water on the ground was stormwater following heavy rain.

Later that day, the land slippage occurred. At that point the main ruptured completely and the alarm on the reservoir control system went off, indicating high leakage. Sydney Water worked quickly to restore the water supply from another reservoir to the community later that night.

Over the following two months, Sydney Water replaced the critical water main, scheduling work around Woollahra Council’s restoration of the damage caused by the land slippage.

Since the Bellevue Hill incident, Sydney Water has reviewed its job-allocation system to ensure that crews are sent to the correct location. New field leak detection and investigation procedures are being implemented, with priority given to mains located in potential land slip areas.

Water asset upgrades

Sydney Water is continuing its long-term project to reline all steel water storage reservoirs. The old bitumen coating in these reservoirs is being replaced with epoxy. This is longer lasting and reduces the potential for taste and odour causing compounds to occur. Five reservoirs were relined in 2008–09. While reservoirs are being relined, system connections are changed so that water supply can be maintained to customers.

In recent years, Sydney Water has identified the potential effect on assets in the unlikely event of an earthquake. Initially, elevated reservoirs, critical water mains and other high-risk assets have been identified.

In 2008–09, Sydney Water assessed the structure of 17 elevated reservoirs, three upgrades were carried out and a further 12 upgrades identified to address earthquake impacts. In 2009–10, a further 11 elevated reservoirs will be assessed.

Further information and test results are available at www.sydneywater.com.au/waterquality.

The Sydney Water website contains more information on this topic.